main/utils.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Utility functions
 *
 * \note These are important for portability and security,
 * so please use them in favour of other routines.
 * Please consult the CODING GUIDELINES for more information.
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <ctype.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>
#if defined(__APPLE__)
#include <mach/mach.h>
#elif defined(HAVE_SYS_THR_H)
#include <sys/thr.h>
#endif

#include "asterisk/network.h"
#include "asterisk/ast_version.h"

#define AST_API_MODULE     /* ensure that inlinable API functions will be built in lock.h if required */
#include "asterisk/lock.h"
#include "asterisk/io.h"
#include "asterisk/md5.h"
#include "asterisk/sha1.h"
#include "asterisk/cli.h"
#include "asterisk/linkedlists.h"
#include "asterisk/astobj2.h"

#define AST_API_MODULE     /* ensure that inlinable API functions will be built in this module if required */
#include "asterisk/strings.h"

#define AST_API_MODULE     /* ensure that inlinable API functions will be built in this module if required */
#include "asterisk/time.h"

#define AST_API_MODULE     /* ensure that inlinable API functions will be built in this module if required */
#include "asterisk/utils.h"

#define AST_API_MODULE
#include "asterisk/threadstorage.h"

#define AST_API_MODULE
#include "asterisk/config.h"

#define AST_API_MODULE
#include "asterisk/alertpipe.h"

static char base64[64];
static char b2a[256];

AST_THREADSTORAGE(inet_ntoa_buf);

#if !defined(HAVE_GETHOSTBYNAME_R_5) && !defined(HAVE_GETHOSTBYNAME_R_6)

#define ERANGE 34 /*!< duh? ERANGE value copied from web... */
#undef gethostbyname

AST_MUTEX_DEFINE_STATIC(__mutex);

/*! \brief Reentrant replacement for gethostbyname for BSD-based systems.
\note This
routine is derived from code originally written and placed in the public
domain by Enzo Michelangeli <em@em.no-ip.com> */

static int gethostbyname_r (const char *name, struct hostent *ret, char *buf,
            size_t buflen, struct hostent **result,
            int *h_errnop)
{
   int hsave;
   struct hostent *ph;
   ast_mutex_lock(&__mutex); /* begin critical area */
   hsave = h_errno;

   ph = gethostbyname(name);
   *h_errnop = h_errno; /* copy h_errno to *h_herrnop */
   if (ph == NULL) {
      *result = NULL;
   } else {
      char **p, **q;
      char *pbuf;
      int nbytes = 0;
      int naddr = 0, naliases = 0;
      /* determine if we have enough space in buf */

      /* count how many addresses */
      for (p = ph->h_addr_list; *p != 0; p++) {
         nbytes += ph->h_length; /* addresses */
         nbytes += sizeof(*p); /* pointers */
         naddr++;
      }
      nbytes += sizeof(*p); /* one more for the terminating NULL */

      /* count how many aliases, and total length of strings */
      for (p = ph->h_aliases; *p != 0; p++) {
         nbytes += (strlen(*p)+1); /* aliases */
         nbytes += sizeof(*p);  /* pointers */
         naliases++;
      }
      nbytes += sizeof(*p); /* one more for the terminating NULL */

      /* here nbytes is the number of bytes required in buffer */
      /* as a terminator must be there, the minimum value is ph->h_length */
      if (nbytes > buflen) {
         *result = NULL;
         ast_mutex_unlock(&__mutex); /* end critical area */
         return ERANGE; /* not enough space in buf!! */
      }

      /* There is enough space. Now we need to do a deep copy! */
      /* Allocation in buffer:
         from [0] to [(naddr-1) * sizeof(*p)]:
         pointers to addresses
         at [naddr * sizeof(*p)]:
         NULL
         from [(naddr+1) * sizeof(*p)] to [(naddr+naliases) * sizeof(*p)] :
         pointers to aliases
         at [(naddr+naliases+1) * sizeof(*p)]:
         NULL
         then naddr addresses (fixed length), and naliases aliases (asciiz).
      */

      *ret = *ph;   /* copy whole structure (not its address!) */

      /* copy addresses */
      q = (char **)buf; /* pointer to pointers area (type: char **) */
      ret->h_addr_list = q; /* update pointer to address list */
      pbuf = buf + ((naddr + naliases + 2) * sizeof(*p)); /* skip that area */
      for (p = ph->h_addr_list; *p != 0; p++) {
         memcpy(pbuf, *p, ph->h_length); /* copy address bytes */
         *q++ = pbuf; /* the pointer is the one inside buf... */
         pbuf += ph->h_length; /* advance pbuf */
      }
      *q++ = NULL; /* address list terminator */

      /* copy aliases */
      ret->h_aliases = q; /* update pointer to aliases list */
      for (p = ph->h_aliases; *p != 0; p++) {
         strcpy(pbuf, *p); /* copy alias strings */
         *q++ = pbuf; /* the pointer is the one inside buf... */
         pbuf += strlen(*p); /* advance pbuf */
         *pbuf++ = 0; /* string terminator */
      }
      *q++ = NULL; /* terminator */

      strcpy(pbuf, ph->h_name); /* copy alias strings */
      ret->h_name = pbuf;
      pbuf += strlen(ph->h_name); /* advance pbuf */
      *pbuf++ = 0; /* string terminator */

      *result = ret;  /* and let *result point to structure */

   }
   h_errno = hsave;  /* restore h_errno */
   ast_mutex_unlock(&__mutex); /* end critical area */

   return (*result == NULL); /* return 0 on success, non-zero on error */
}


#endif

/*! \brief Re-entrant (thread safe) version of gethostbyname that replaces the
   standard gethostbyname (which is not thread safe)
*/
struct hostent *ast_gethostbyname(const char *host, struct ast_hostent *hp)
{
#ifndef HAVE_GETHOSTBYNAME_R_5
   int res;
#endif
   int herrno;
   int dots = 0;
   const char *s;
   struct hostent *result = NULL;
   /* Although it is perfectly legitimate to lookup a pure integer, for
      the sake of the sanity of people who like to name their peers as
      integers, we break with tradition and refuse to look up a
      pure integer */
   s = host;
   while (s && *s) {
      if (*s == '.')
         dots++;
      else if (!isdigit(*s))
         break;
      s++;
   }
   if (!s || !*s) {
      /* Forge a reply for IP's to avoid octal IP's being interpreted as octal */
      if (dots != 3)
         return NULL;
      memset(hp, 0, sizeof(struct ast_hostent));
      hp->hp.h_addrtype = AF_INET;
      hp->hp.h_addr_list = (void *) hp->buf;
      hp->hp.h_addr = hp->buf + sizeof(void *);
      /* For AF_INET, this will always be 4 */
      hp->hp.h_length = 4;
      if (inet_pton(AF_INET, host, hp->hp.h_addr) > 0)
         return &hp->hp;
      return NULL;

   }
#ifdef HAVE_GETHOSTBYNAME_R_5
   result = gethostbyname_r(host, &hp->hp, hp->buf, sizeof(hp->buf), &herrno);

   if (!result || !hp->hp.h_addr_list || !hp->hp.h_addr_list[0])
      return NULL;
#else
   res = gethostbyname_r(host, &hp->hp, hp->buf, sizeof(hp->buf), &result, &herrno);

   if (res || !result || !hp->hp.h_addr_list || !hp->hp.h_addr_list[0])
      return NULL;
#endif
   return &hp->hp;
}

/*! \brief Produce 32 char MD5 hash of value. */
void ast_md5_hash(char *output, const char *input)
{
   struct MD5Context md5;
   unsigned char digest[16];
   char *ptr;
   int x;

   MD5Init(&md5);
   MD5Update(&md5, (const unsigned char *) input, strlen(input));
   MD5Final(digest, &md5);
   ptr = output;
   for (x = 0; x < 16; x++)
      ptr += sprintf(ptr, "%02hhx", digest[x]);
}

/*! \brief Produce 40 char SHA1 hash of value. */
void ast_sha1_hash(char *output, const char *input)
{
   struct SHA1Context sha;
   char *ptr;
   int x;
   uint8_t Message_Digest[20];

   SHA1Reset(&sha);

   SHA1Input(&sha, (const unsigned char *) input, strlen(input));

   SHA1Result(&sha, Message_Digest);
   ptr = output;
   for (x = 0; x < 20; x++)
      ptr += sprintf(ptr, "%02hhx", Message_Digest[x]);
}

/*! \brief Produce a 20 byte SHA1 hash of value. */
void ast_sha1_hash_uint(uint8_t *digest, const char *input)
{
        struct SHA1Context sha;

        SHA1Reset(&sha);

        SHA1Input(&sha, (const unsigned char *) input, strlen(input));

        SHA1Result(&sha, digest);
}

/*! \brief decode BASE64 encoded text */
int ast_base64decode(unsigned char *dst, const char *src, int max)
{
   int cnt = 0;
   unsigned int byte = 0;
   unsigned int bits = 0;
   int incnt = 0;
   while(*src && *src != '=' && (cnt < max)) {
      /* Shift in 6 bits of input */
      byte <<= 6;
      byte |= (b2a[(int)(*src)]) & 0x3f;
      bits += 6;
      src++;
      incnt++;
      /* If we have at least 8 bits left over, take that character
         off the top */
      if (bits >= 8)  {
         bits -= 8;
         *dst = (byte >> bits) & 0xff;
         dst++;
         cnt++;
      }
   }
   /* Don't worry about left over bits, they're extra anyway */
   return cnt;
}

/*! \brief Decode BASE64 encoded text and return the string */
char *ast_base64decode_string(const char *src)
{
   size_t encoded_len;
   size_t decoded_len;
   int padding = 0;
   unsigned char *decoded_string;

   if (ast_strlen_zero(src)) {
      return NULL;
   }

   encoded_len = strlen(src);
   if (encoded_len > 2 && src[encoded_len - 1] == '=') {
      padding++;
      if (src[encoded_len - 2] == '=') {
         padding++;
      }
   }

   decoded_len = (encoded_len / 4 * 3) - padding;
   decoded_string = ast_malloc(decoded_len + 1);
   if (!decoded_string) {
      return NULL;
   }

   ast_base64decode(decoded_string, src, decoded_len);
   decoded_string[decoded_len] = '\0';

   return (char *)decoded_string;
}

/*! \brief encode text to BASE64 coding */
int ast_base64encode_full(char *dst, const unsigned char *src, int srclen, int max, int linebreaks)
{
   int cnt = 0;
   int col = 0;
   unsigned int byte = 0;
   int bits = 0;
   int cntin = 0;
   /* Reserve space for null byte at end of string */
   max--;
   while ((cntin < srclen) && (cnt < max)) {
      byte <<= 8;
      byte |= *(src++);
      bits += 8;
      cntin++;
      if ((bits == 24) && (cnt + 4 <= max)) {
         *dst++ = base64[(byte >> 18) & 0x3f];
         *dst++ = base64[(byte >> 12) & 0x3f];
         *dst++ = base64[(byte >> 6) & 0x3f];
         *dst++ = base64[byte & 0x3f];
         cnt += 4;
         col += 4;
         bits = 0;
         byte = 0;
      }
      if (linebreaks && (cnt < max) && (col == 64)) {
         *dst++ = '\n';
         cnt++;
         col = 0;
      }
   }
   if (bits && (cnt + 4 <= max)) {
      /* Add one last character for the remaining bits,
         padding the rest with 0 */
      byte <<= 24 - bits;
      *dst++ = base64[(byte >> 18) & 0x3f];
      *dst++ = base64[(byte >> 12) & 0x3f];
      if (bits == 16)
         *dst++ = base64[(byte >> 6) & 0x3f];
      else
         *dst++ = '=';
      *dst++ = '=';
      cnt += 4;
   }
   if (linebreaks && (cnt < max)) {
      *dst++ = '\n';
      cnt++;
   }
   *dst = '\0';
   return cnt;
}

int ast_base64encode(char *dst, const unsigned char *src, int srclen, int max)
{
   return ast_base64encode_full(dst, src, srclen, max, 0);
}

/*! \brief Encode to BASE64 and return encoded string */
char *ast_base64encode_string(const char *src)
{
   size_t encoded_len;
   char *encoded_string;

   if (ast_strlen_zero(src)) {
      return NULL;
   }

   encoded_len = ((strlen(src) * 4 / 3 + 3) & ~3) + 1;
   encoded_string = ast_calloc(1, encoded_len);

   ast_base64encode(encoded_string, (const unsigned char *)src, strlen(src), encoded_len);

   return encoded_string;
}

static void base64_init(void)
{
   int x;
   memset(b2a, -1, sizeof(b2a));
   /* Initialize base-64 Conversion table */
   for (x = 0; x < 26; x++) {
      /* A-Z */
      base64[x] = 'A' + x;
      b2a['A' + x] = x;
      /* a-z */
      base64[x + 26] = 'a' + x;
      b2a['a' + x] = x + 26;
      /* 0-9 */
      if (x < 10) {
         base64[x + 52] = '0' + x;
         b2a['0' + x] = x + 52;
      }
   }
   base64[62] = '+';
   base64[63] = '/';
   b2a[(int)'+'] = 62;
   b2a[(int)'/'] = 63;
}

const struct ast_flags ast_uri_http = {AST_URI_UNRESERVED};
const struct ast_flags ast_uri_http_legacy = {AST_URI_LEGACY_SPACE | AST_URI_UNRESERVED};
const struct ast_flags ast_uri_sip_user = {AST_URI_UNRESERVED | AST_URI_SIP_USER_UNRESERVED};

char *ast_uri_encode(const char *string, char *outbuf, int buflen, struct ast_flags spec)
{
   const char *ptr  = string; /* Start with the string */
   char *out = outbuf;
   const char *mark = "-_.!~*'()"; /* no encode set, RFC 2396 section 2.3, RFC 3261 sec 25 */
   const char *user_unreserved = "&=+$,;?/"; /* user-unreserved set, RFC 3261 sec 25 */

   while (*ptr && out - outbuf < buflen - 1) {
      if (ast_test_flag(&spec, AST_URI_LEGACY_SPACE) && *ptr == ' ') {
         /* for legacy encoding, encode spaces as '+' */
         *out = '+';
         out++;
      } else if (!(ast_test_flag(&spec, AST_URI_MARK)
            && strchr(mark, *ptr))
         && !(ast_test_flag(&spec, AST_URI_ALPHANUM)
            && ((*ptr >= '0' && *ptr <= '9')
            || (*ptr >= 'A' && *ptr <= 'Z')
            || (*ptr >= 'a' && *ptr <= 'z')))
         && !(ast_test_flag(&spec, AST_URI_SIP_USER_UNRESERVED)
            && strchr(user_unreserved, *ptr))) {

         if (out - outbuf >= buflen - 3) {
            break;
         }
         out += sprintf(out, "%%%02hhX", (unsigned char) *ptr);
      } else {
         *out = *ptr;   /* Continue copying the string */
         out++;
      }
      ptr++;
   }

   if (buflen) {
      *out = '\0';
   }

   return outbuf;
}

void ast_uri_decode(char *s, struct ast_flags spec)
{
   char *o;
   unsigned int tmp;

   for (o = s; *s; s++, o++) {
      if (ast_test_flag(&spec, AST_URI_LEGACY_SPACE) && *s == '+') {
         /* legacy mode, decode '+' as space */
         *o = ' ';
      } else if (*s == '%' && s[1] != '\0' && s[2] != '\0' && sscanf(s + 1, "%2x", &tmp) == 1) {
         /* have '%', two chars and correct parsing */
         *o = tmp;
         s += 2;  /* Will be incremented once more when we break out */
      } else /* all other cases, just copy */
         *o = *s;
   }
   *o = '\0';
}

char *ast_escape_quoted(const char *string, char *outbuf, int buflen)
{
   const char *ptr  = string;
   char *out = outbuf;
   char *allow = "\t\v !"; /* allow LWS (minus \r and \n) and "!" */

   while (*ptr && out - outbuf < buflen - 1) {
      if (!(strchr(allow, *ptr))
         && !(*ptr >= '#' && *ptr <= '[') /* %x23 - %x5b */
         && !(*ptr >= ']' && *ptr <= '~') /* %x5d - %x7e */
         && !((unsigned char) *ptr > 0x7f)) {             /* UTF8-nonascii */

         if (out - outbuf >= buflen - 2) {
            break;
         }
         out += sprintf(out, "\\%c", (unsigned char) *ptr);
      } else {
         *out = *ptr;
         out++;
      }
      ptr++;
   }

   if (buflen) {
      *out = '\0';
   }

   return outbuf;
}

char *ast_escape_semicolons(const char *string, char *outbuf, int buflen)
{
   const char *ptr = string;
   char *out = outbuf;

   if (string == NULL || outbuf == NULL) {
      ast_assert(string != NULL && outbuf != NULL);
      return NULL;
   }

   while (*ptr && out - outbuf < buflen - 1) {
      if (*ptr == ';') {
         if (out - outbuf >= buflen - 2) {
            break;
         }
         strcpy(out, "\\;");
         out += 2;
      } else {
         *out = *ptr;
         out++;
      }
      ptr++;
   }

   if (buflen) {
      *out = '\0';
   }

   return outbuf;
}

void ast_unescape_quoted(char *quote_str)
{
   int esc_pos;
   int unesc_pos;
   int quote_str_len = strlen(quote_str);

   for (esc_pos = 0, unesc_pos = 0;
      esc_pos < quote_str_len;
      esc_pos++, unesc_pos++) {
      if (quote_str[esc_pos] == '\\') {
         /* at least one more char and current is \\ */
         esc_pos++;
         if (esc_pos >= quote_str_len) {
            break;
         }
      }

      quote_str[unesc_pos] = quote_str[esc_pos];
   }
   quote_str[unesc_pos] = '\0';
}

int ast_xml_escape(const char *string, char * const outbuf, const size_t buflen)
{
   char *dst = outbuf;
   char *end = outbuf + buflen - 1; /* save one for the null terminator */

   /* Handle the case for the empty output buffer */
   if (buflen == 0) {
      return -1;
   }

   /* Escaping rules from http://www.w3.org/TR/REC-xml/#syntax */
   /* This also prevents partial entities at the end of a string */
   while (*string && dst < end) {
      const char *entity = NULL;
      int len = 0;

      switch (*string) {
      case '<':
         entity = "&lt;";
         len = 4;
         break;
      case '&':
         entity = "&amp;";
         len = 5;
         break;
      case '>':
         /* necessary if ]]> is in the string; easier to escape them all */
         entity = "&gt;";
         len = 4;
         break;
      case '\'':
         /* necessary in single-quoted strings; easier to escape them all */
         entity = "&apos;";
         len = 6;
         break;
      case '"':
         /* necessary in double-quoted strings; easier to escape them all */
         entity = "&quot;";
         len = 6;
         break;
      default:
         *dst++ = *string++;
         break;
      }

      if (entity) {
         ast_assert(len == strlen(entity));
         if (end - dst < len) {
            /* no room for the entity; stop */
            break;
         }
         /* just checked for length; strcpy is fine */
         strcpy(dst, entity);
         dst += len;
         ++string;
      }
   }
   /* Write null terminator */
   *dst = '\0';
   /* If any chars are left in string, return failure */
   return *string == '\0' ? 0 : -1;
}

/*! \brief  ast_inet_ntoa: Recursive thread safe replacement of inet_ntoa */
const char *ast_inet_ntoa(struct in_addr ia)
{
   char *buf;

   if (!(buf = ast_threadstorage_get(&inet_ntoa_buf, INET_ADDRSTRLEN)))
      return "";

   return inet_ntop(AF_INET, &ia, buf, INET_ADDRSTRLEN);
}

static int dev_urandom_fd = -1;

#ifndef __linux__
#undef pthread_create /* For ast_pthread_create function only */
#endif /* !__linux__ */

#ifdef DEBUG_THREADS

#if !defined(LOW_MEMORY)
/*! \brief A reasonable maximum number of locks a thread would be holding ... */
#define AST_MAX_LOCKS 64

/* Allow direct use of pthread_mutex_t and friends */
#undef pthread_mutex_t
#undef pthread_mutex_lock
#undef pthread_mutex_unlock
#undef pthread_mutex_init
#undef pthread_mutex_destroy

/*!
 * \brief Keep track of which locks a thread holds
 *
 * There is an instance of this struct for every active thread
 */
struct thr_lock_info {
   /*! The thread's ID */
   pthread_t thread_id;
   /*! The thread name which includes where the thread was started */
   const char *thread_name;
   /*! This is the actual container of info for what locks this thread holds */
   struct {
      const char *file;
      const char *func;
      const char *lock_name;
      void *lock_addr;
      int times_locked;
      int line_num;
      enum ast_lock_type type;
      /*! This thread is waiting on this lock */
      int pending:2;
      /*! A condition has suspended this lock */
      int suspended:1;
#ifdef HAVE_BKTR
      struct ast_bt *backtrace;
#endif
   } locks[AST_MAX_LOCKS];
   /*! This is the number of locks currently held by this thread.
    *  The index (num_locks - 1) has the info on the last one in the
    *  locks member */
   unsigned int num_locks;
   /*! The LWP id (which GDB prints) */
   int lwp;
   /*! Protects the contents of the locks member
    * Intentionally not ast_mutex_t */
   pthread_mutex_t lock;
   AST_LIST_ENTRY(thr_lock_info) entry;
};

/*!
 * \brief Locked when accessing the lock_infos list
 */
AST_MUTEX_DEFINE_STATIC(lock_infos_lock);
/*!
 * \brief A list of each thread's lock info
 */
static AST_LIST_HEAD_NOLOCK_STATIC(lock_infos, thr_lock_info);

/*!
 * \brief Destroy a thread's lock info
 *
 * This gets called automatically when the thread stops
 */
static void lock_info_destroy(void *data)
{
   struct thr_lock_info *lock_info = data;
   int i;

   pthread_mutex_lock(&lock_infos_lock.mutex);
   AST_LIST_REMOVE(&lock_infos, lock_info, entry);
   pthread_mutex_unlock(&lock_infos_lock.mutex);


   for (i = 0; i < lock_info->num_locks; i++) {
      if (lock_info->locks[i].pending == -1) {
         /* This just means that the last lock this thread went for was by
          * using trylock, and it failed.  This is fine. */
         break;
      }

      ast_log(LOG_ERROR,
         "Thread '%s' still has a lock! - '%s' (%p) from '%s' in %s:%d!\n",
         lock_info->thread_name,
         lock_info->locks[i].lock_name,
         lock_info->locks[i].lock_addr,
         lock_info->locks[i].func,
         lock_info->locks[i].file,
         lock_info->locks[i].line_num
      );
   }

   pthread_mutex_destroy(&lock_info->lock);
   if (lock_info->thread_name) {
      ast_free((void *) lock_info->thread_name);
   }
   ast_free(lock_info);
}

/*!
 * \brief The thread storage key for per-thread lock info
 */
AST_THREADSTORAGE_CUSTOM(thread_lock_info, NULL, lock_info_destroy);
#endif /* ! LOW_MEMORY */

void ast_store_lock_info(enum ast_lock_type type, const char *filename,
   int line_num, const char *func, const char *lock_name, void *lock_addr, struct ast_bt *bt)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   int i;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return;

   pthread_mutex_lock(&lock_info->lock);

   for (i = 0; i < lock_info->num_locks; i++) {
      if (lock_info->locks[i].lock_addr == lock_addr) {
         lock_info->locks[i].times_locked++;
#ifdef HAVE_BKTR
         lock_info->locks[i].backtrace = bt;
#endif
         pthread_mutex_unlock(&lock_info->lock);
         return;
      }
   }

   if (lock_info->num_locks == AST_MAX_LOCKS) {
      /* Can't use ast_log here, because it will cause infinite recursion */
      fprintf(stderr, "XXX ERROR XXX A thread holds more locks than '%d'."
         "  Increase AST_MAX_LOCKS!\n", AST_MAX_LOCKS);
      pthread_mutex_unlock(&lock_info->lock);
      return;
   }

   if (i && lock_info->locks[i - 1].pending == -1) {
      /* The last lock on the list was one that this thread tried to lock but
       * failed at doing so.  It has now moved on to something else, so remove
       * the old lock from the list. */
      i--;
      lock_info->num_locks--;
      memset(&lock_info->locks[i], 0, sizeof(lock_info->locks[0]));
   }

   lock_info->locks[i].file = filename;
   lock_info->locks[i].line_num = line_num;
   lock_info->locks[i].func = func;
   lock_info->locks[i].lock_name = lock_name;
   lock_info->locks[i].lock_addr = lock_addr;
   lock_info->locks[i].times_locked = 1;
   lock_info->locks[i].type = type;
   lock_info->locks[i].pending = 1;
#ifdef HAVE_BKTR
   lock_info->locks[i].backtrace = bt;
#endif
   lock_info->num_locks++;

   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}

void ast_mark_lock_acquired(void *lock_addr)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return;

   pthread_mutex_lock(&lock_info->lock);
   if (lock_info->locks[lock_info->num_locks - 1].lock_addr == lock_addr) {
      lock_info->locks[lock_info->num_locks - 1].pending = 0;
   }
   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}

void ast_mark_lock_failed(void *lock_addr)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return;

   pthread_mutex_lock(&lock_info->lock);
   if (lock_info->locks[lock_info->num_locks - 1].lock_addr == lock_addr) {
      lock_info->locks[lock_info->num_locks - 1].pending = -1;
      lock_info->locks[lock_info->num_locks - 1].times_locked--;
   }
   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}

int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, int *lineno, char *func, size_t func_size, char *mutex_name, size_t mutex_name_size)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   int i = 0;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return -1;

   pthread_mutex_lock(&lock_info->lock);

   for (i = lock_info->num_locks - 1; i >= 0; i--) {
      if (lock_info->locks[i].lock_addr == lock_addr)
         break;
   }

   if (i == -1) {
      /* Lock not found :( */
      pthread_mutex_unlock(&lock_info->lock);
      return -1;
   }

   ast_copy_string(filename, lock_info->locks[i].file, filename_size);
   *lineno = lock_info->locks[i].line_num;
   ast_copy_string(func, lock_info->locks[i].func, func_size);
   ast_copy_string(mutex_name, lock_info->locks[i].lock_name, mutex_name_size);

   pthread_mutex_unlock(&lock_info->lock);

   return 0;
#else /* if defined(LOW_MEMORY) */
   return -1;
#endif
}

void ast_suspend_lock_info(void *lock_addr)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   int i = 0;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info)))) {
      return;
   }

   pthread_mutex_lock(&lock_info->lock);

   for (i = lock_info->num_locks - 1; i >= 0; i--) {
      if (lock_info->locks[i].lock_addr == lock_addr)
         break;
   }

   if (i == -1) {
      /* Lock not found :( */
      pthread_mutex_unlock(&lock_info->lock);
      return;
   }

   lock_info->locks[i].suspended = 1;

   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}

void ast_restore_lock_info(void *lock_addr)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   int i = 0;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return;

   pthread_mutex_lock(&lock_info->lock);

   for (i = lock_info->num_locks - 1; i >= 0; i--) {
      if (lock_info->locks[i].lock_addr == lock_addr)
         break;
   }

   if (i == -1) {
      /* Lock not found :( */
      pthread_mutex_unlock(&lock_info->lock);
      return;
   }

   lock_info->locks[i].suspended = 0;

   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}


void ast_remove_lock_info(void *lock_addr, struct ast_bt *bt)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   int i = 0;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return;

   pthread_mutex_lock(&lock_info->lock);

   for (i = lock_info->num_locks - 1; i >= 0; i--) {
      if (lock_info->locks[i].lock_addr == lock_addr)
         break;
   }

   if (i == -1) {
      /* Lock not found :( */
      pthread_mutex_unlock(&lock_info->lock);
      return;
   }

   if (lock_info->locks[i].times_locked > 1) {
      lock_info->locks[i].times_locked--;
#ifdef HAVE_BKTR
      lock_info->locks[i].backtrace = bt;
#endif
      pthread_mutex_unlock(&lock_info->lock);
      return;
   }

   if (i < lock_info->num_locks - 1) {
      /* Not the last one ... *should* be rare! */
      memmove(&lock_info->locks[i], &lock_info->locks[i + 1],
         (lock_info->num_locks - (i + 1)) * sizeof(lock_info->locks[0]));
   }

   lock_info->num_locks--;

   pthread_mutex_unlock(&lock_info->lock);
#endif /* ! LOW_MEMORY */
}

#if !defined(LOW_MEMORY)
static const char *locktype2str(enum ast_lock_type type)
{
   switch (type) {
   case AST_MUTEX:
      return "MUTEX";
   case AST_RDLOCK:
      return "RDLOCK";
   case AST_WRLOCK:
      return "WRLOCK";
   }

   return "UNKNOWN";
}

#ifdef HAVE_BKTR
static void append_backtrace_information(struct ast_str **str, struct ast_bt *bt)
{
   struct ast_vector_string *symbols;
   int num_frames;

   if (!bt) {
      ast_str_append(str, 0, "\tNo backtrace to print\n");
      return;
   }

   /* store frame count locally to avoid the memory corruption that
    * sometimes happens on virtualized CentOS 6.x systems */
   num_frames = bt->num_frames;
   if ((symbols = ast_bt_get_symbols(bt->addresses, num_frames))) {
      int frame_iterator;

      for (frame_iterator = 1; frame_iterator < AST_VECTOR_SIZE(symbols); ++frame_iterator) {
         ast_str_append(str, 0, "\t%s\n", AST_VECTOR_GET(symbols, frame_iterator));
      }

      ast_bt_free_symbols(symbols);
   } else {
      ast_str_append(str, 0, "\tCouldn't retrieve backtrace symbols\n");
   }
}
#endif

static void append_lock_information(struct ast_str **str, struct thr_lock_info *lock_info, int i)
{
   int j;
   ast_mutex_t *lock;
   struct ast_lock_track *lt;

   ast_str_append(str, 0, "=== ---> %sLock #%d (%s): %s %d %s %s %p (%d%s)\n",
               lock_info->locks[i].pending > 0 ? "Waiting for " :
               lock_info->locks[i].pending < 0 ? "Tried and failed to get " : "", i,
               lock_info->locks[i].file,
               locktype2str(lock_info->locks[i].type),
               lock_info->locks[i].line_num,
               lock_info->locks[i].func, lock_info->locks[i].lock_name,
               lock_info->locks[i].lock_addr,
               lock_info->locks[i].times_locked,
               lock_info->locks[i].suspended ? " - suspended" : "");
#ifdef HAVE_BKTR
   append_backtrace_information(str, lock_info->locks[i].backtrace);
#endif

   if (!lock_info->locks[i].pending || lock_info->locks[i].pending == -1)
      return;

   /* We only have further details for mutexes right now */
   if (lock_info->locks[i].type != AST_MUTEX)
      return;

   lock = lock_info->locks[i].lock_addr;
   lt = lock->track;
   ast_reentrancy_lock(lt);
   for (j = 0; *str && j < lt->reentrancy; j++) {
      ast_str_append(str, 0, "=== --- ---> Locked Here: %s line %d (%s)\n",
                  lt->file[j], lt->lineno[j], lt->func[j]);
   }
   ast_reentrancy_unlock(lt);
}
#endif /* ! LOW_MEMORY */

/*! This function can help you find highly temporal locks; locks that happen for a
    short time, but at unexpected times, usually at times that create a deadlock,
   Why is this thing locked right then? Who is locking it? Who am I fighting
    with for this lock?

   To answer such questions, just call this routine before you would normally try
   to aquire a lock. It doesn't do anything if the lock is not acquired. If the
   lock is taken, it will publish a line or two to the console via ast_log().

   Sometimes, the lock message is pretty uninformative. For instance, you might
   find that the lock is being aquired deep within the astobj2 code; this tells
   you little about higher level routines that call the astobj2 routines.
   But, using gdb, you can set a break at the ast_log below, and for that
   breakpoint, you can set the commands:
     where
     cont
   which will give a stack trace and continue. -- that aught to do the job!

*/
void ast_log_show_lock(void *this_lock_addr)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   struct ast_str *str;

   if (!(str = ast_str_create(4096))) {
      ast_log(LOG_NOTICE,"Could not create str\n");
      return;
   }


   pthread_mutex_lock(&lock_infos_lock.mutex);
   AST_LIST_TRAVERSE(&lock_infos, lock_info, entry) {
      int i;
      pthread_mutex_lock(&lock_info->lock);
      for (i = 0; str && i < lock_info->num_locks; i++) {
         /* ONLY show info about this particular lock, if
            it's acquired... */
         if (lock_info->locks[i].lock_addr == this_lock_addr) {
            append_lock_information(&str, lock_info, i);
            ast_log(LOG_NOTICE, "%s", ast_str_buffer(str));
            break;
         }
      }
      pthread_mutex_unlock(&lock_info->lock);
   }
   pthread_mutex_unlock(&lock_infos_lock.mutex);
   ast_free(str);
#endif /* ! LOW_MEMORY */
}


struct ast_str *ast_dump_locks(void)
{
#if !defined(LOW_MEMORY)
   struct thr_lock_info *lock_info;
   struct ast_str *str;

   if (!(str = ast_str_create(4096))) {
      return NULL;
   }

   ast_str_append(&str, 0, "\n"
                  "=======================================================================\n"
                  "=== %s\n"
                  "=== Currently Held Locks\n"
                  "=======================================================================\n"
                  "===\n"
                  "=== <pending> <lock#> (<file>): <lock type> <line num> <function> <lock name> <lock addr> (times locked)\n"
                  "===\n", ast_get_version());

   if (!str) {
      return NULL;
   }

   pthread_mutex_lock(&lock_infos_lock.mutex);
   AST_LIST_TRAVERSE(&lock_infos, lock_info, entry) {
      int i;
      int header_printed = 0;
      pthread_mutex_lock(&lock_info->lock);
      for (i = 0; str && i < lock_info->num_locks; i++) {
         /* Don't show suspended locks */
         if (lock_info->locks[i].suspended) {
            continue;
         }

         if (!header_printed) {
            if (lock_info->lwp != -1) {
               ast_str_append(&str, 0, "=== Thread ID: 0x%lx LWP:%d (%s)\n",
                  (long unsigned) lock_info->thread_id, lock_info->lwp, lock_info->thread_name);
            } else {
               ast_str_append(&str, 0, "=== Thread ID: 0x%lx (%s)\n",
                  (long unsigned) lock_info->thread_id, lock_info->thread_name);
            }
            header_printed = 1;
         }

         append_lock_information(&str, lock_info, i);
      }
      pthread_mutex_unlock(&lock_info->lock);
      if (!str) {
         break;
      }
      if (header_printed) {
         ast_str_append(&str, 0, "=== -------------------------------------------------------------------\n"
            "===\n");
      }
      if (!str) {
         break;
      }
   }
   pthread_mutex_unlock(&lock_infos_lock.mutex);

   if (!str) {
      return NULL;
   }

   ast_str_append(&str, 0, "=======================================================================\n"
                  "\n");

   return str;
#else /* if defined(LOW_MEMORY) */
   return NULL;
#endif
}

#if !defined(LOW_MEMORY)
static char *handle_show_locks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_str *str;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show locks";
      e->usage =
         "Usage: core show locks\n"
         "       This command is for lock debugging.  It prints out which locks\n"
         "are owned by each active thread.\n";
      ast_cli_allow_at_shutdown(e);
      return NULL;

   case CLI_GENERATE:
      return NULL;
   }

   str = ast_dump_locks();
   if (!str) {
      return CLI_FAILURE;
   }

   ast_cli(a->fd, "%s", ast_str_buffer(str));

   ast_free(str);

   return CLI_SUCCESS;
}

static struct ast_cli_entry utils_cli[] = {
   AST_CLI_DEFINE(handle_show_locks, "Show which locks are held by which thread"),
};
#endif /* ! LOW_MEMORY */
#endif /* DEBUG_THREADS */

#if !defined(LOW_MEMORY)
/*
 * support for 'show threads'. The start routine is wrapped by
 * dummy_start(), so that ast_register_thread() and
 * ast_unregister_thread() know the thread identifier.
 */
struct thr_arg {
   void *(*start_routine)(void *);
   void *data;
   char *name;
};

/*
 * on OS/X, pthread_cleanup_push() and pthread_cleanup_pop()
 * are odd macros which start and end a block, so they _must_ be
 * used in pairs (the latter with a '1' argument to call the
 * handler on exit.
 * On BSD we don't need this, but we keep it for compatibility.
 */
static void *dummy_start(void *data)
{
   void *ret;
   struct thr_arg a = *((struct thr_arg *) data);  /* make a local copy */
#ifdef DEBUG_THREADS
   struct thr_lock_info *lock_info;
   pthread_mutexattr_t mutex_attr;

   if (!(lock_info = ast_threadstorage_get(&thread_lock_info, sizeof(*lock_info))))
      return NULL;

   lock_info->thread_id = pthread_self();
   lock_info->lwp = ast_get_tid();
   lock_info->thread_name = ast_strdup(a.name);

   pthread_mutexattr_init(&mutex_attr);
   pthread_mutexattr_settype(&mutex_attr, AST_MUTEX_KIND);
   pthread_mutex_init(&lock_info->lock, &mutex_attr);
   pthread_mutexattr_destroy(&mutex_attr);

   pthread_mutex_lock(&lock_infos_lock.mutex); /* Intentionally not the wrapper */
   AST_LIST_INSERT_TAIL(&lock_infos, lock_info, entry);
   pthread_mutex_unlock(&lock_infos_lock.mutex); /* Intentionally not the wrapper */
#endif /* DEBUG_THREADS */

   /* note that even though data->name is a pointer to allocated memory,
      we are not freeing it here because ast_register_thread is going to
      keep a copy of the pointer and then ast_unregister_thread will
      free the memory
   */
   ast_free(data);
   ast_register_thread(a.name);
   pthread_cleanup_push(ast_unregister_thread, (void *) pthread_self());

   ret = a.start_routine(a.data);

   pthread_cleanup_pop(1);

   return ret;
}

#endif /* !LOW_MEMORY */

int ast_background_stacksize(void)
{
#if !defined(LOW_MEMORY)
   return AST_STACKSIZE;
#else
   return AST_STACKSIZE_LOW;
#endif
}

int ast_pthread_create_stack(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine)(void *),
              void *data, size_t stacksize, const char *file, const char *caller,
              int line, const char *start_fn)
{
#if !defined(LOW_MEMORY)
   struct thr_arg *a;
#endif

   if (!attr) {
      attr = ast_alloca(sizeof(*attr));
      pthread_attr_init(attr);
   }

#if defined(__linux__) || defined(__FreeBSD__)
   /* On Linux and FreeBSD , pthread_attr_init() defaults to PTHREAD_EXPLICIT_SCHED,
      which is kind of useless. Change this here to
      PTHREAD_INHERIT_SCHED; that way the -p option to set realtime
      priority will propagate down to new threads by default.
      This does mean that callers cannot set a different priority using
      PTHREAD_EXPLICIT_SCHED in the attr argument; instead they must set
      the priority afterwards with pthread_setschedparam(). */
   if ((errno = pthread_attr_setinheritsched(attr, PTHREAD_INHERIT_SCHED)))
      ast_log(LOG_WARNING, "pthread_attr_setinheritsched: %s\n", strerror(errno));
#endif

   if (!stacksize)
      stacksize = AST_STACKSIZE;

   if ((errno = pthread_attr_setstacksize(attr, stacksize ? stacksize : AST_STACKSIZE)))
      ast_log(LOG_WARNING, "pthread_attr_setstacksize: %s\n", strerror(errno));

#if !defined(LOW_MEMORY)
   if ((a = ast_malloc(sizeof(*a)))) {
      a->start_routine = start_routine;
      a->data = data;
      start_routine = dummy_start;
      if (ast_asprintf(&a->name, "%-20s started at [%5d] %s %s()",
              start_fn, line, file, caller) < 0) {
         a->name = NULL;
      }
      data = a;
   }
#endif /* !LOW_MEMORY */

   return pthread_create(thread, attr, start_routine, data); /* We're in ast_pthread_create, so it's okay */
}


int ast_pthread_create_detached_stack(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine)(void *),
              void *data, size_t stacksize, const char *file, const char *caller,
              int line, const char *start_fn)
{
   unsigned char attr_destroy = 0;
   int res;

   if (!attr) {
      attr = ast_alloca(sizeof(*attr));
      pthread_attr_init(attr);
      attr_destroy = 1;
   }

   if ((errno = pthread_attr_setdetachstate(attr, PTHREAD_CREATE_DETACHED)))
      ast_log(LOG_WARNING, "pthread_attr_setdetachstate: %s\n", strerror(errno));

   res = ast_pthread_create_stack(thread, attr, start_routine, data,
                                  stacksize, file, caller, line, start_fn);

   if (attr_destroy)
      pthread_attr_destroy(attr);

   return res;
}

int ast_wait_for_input(int fd, int ms)
{
   struct pollfd pfd[1];

   memset(pfd, 0, sizeof(pfd));
   pfd[0].fd = fd;
   pfd[0].events = POLLIN | POLLPRI;
   return ast_poll(pfd, 1, ms);
}

int ast_wait_for_output(int fd, int ms)
{
   struct pollfd pfd[1];

   memset(pfd, 0, sizeof(pfd));
   pfd[0].fd = fd;
   pfd[0].events = POLLOUT;
   return ast_poll(pfd, 1, ms);
}

static int wait_for_output(int fd, int timeoutms)
{
   struct pollfd pfd = {
      .fd = fd,
      .events = POLLOUT,
   };
   int res;
   struct timeval start = ast_tvnow();
   int elapsed = 0;

   /* poll() until the fd is writable without blocking */
   while ((res = ast_poll(&pfd, 1, timeoutms - elapsed)) <= 0) {
      if (res == 0) {
         /* timed out. */
#ifndef STANDALONE
         ast_debug(1, "Timed out trying to write\n");
#endif
         return -1;
      } else if (res == -1) {
         /* poll() returned an error, check to see if it was fatal */

         if (errno == EINTR || errno == EAGAIN) {
            elapsed = ast_tvdiff_ms(ast_tvnow(), start);
            if (elapsed >= timeoutms) {
               return -1;
            }
            /* This was an acceptable error, go back into poll() */
            continue;
         }

         /* Fatal error, bail. */
         ast_log(LOG_ERROR, "poll returned error: %s\n", strerror(errno));

         return -1;
      }
      elapsed = ast_tvdiff_ms(ast_tvnow(), start);
      if (elapsed >= timeoutms) {
         return -1;
      }
   }

   return 0;
}

/*!
 * Try to write string, but wait no more than ms milliseconds before timing out.
 *
 * \note The code assumes that the file descriptor has NONBLOCK set,
 * so there is only one system call made to do a write, unless we actually
 * have a need to wait.  This way, we get better performance.
 * If the descriptor is blocking, all assumptions on the guaranteed
 * detail do not apply anymore.
 */
int ast_carefulwrite(int fd, char *s, int len, int timeoutms)
{
   struct timeval start = ast_tvnow();
   int res = 0;
   int elapsed = 0;

   while (len) {
      if (wait_for_output(fd, timeoutms - elapsed)) {
         return -1;
      }

      res = write(fd, s, len);

      if (res < 0 && errno != EAGAIN && errno != EINTR) {
         /* fatal error from write() */
         if (errno == EPIPE) {
#ifndef STANDALONE
            ast_debug(1, "write() failed due to reading end being closed: %s\n", strerror(errno));
#endif
         } else {
            ast_log(LOG_ERROR, "write() returned error: %s\n", strerror(errno));
         }
         return -1;
      }

      if (res < 0) {
         /* It was an acceptable error */
         res = 0;
      }

      /* Update how much data we have left to write */
      len -= res;
      s += res;
      res = 0;

      elapsed = ast_tvdiff_ms(ast_tvnow(), start);
      if (elapsed >= timeoutms) {
         /* We've taken too long to write
          * This is only an error condition if we haven't finished writing. */
         res = len ? -1 : 0;
         break;
      }
   }

   return res;
}

char *ast_strip_quoted(char *s, const char *beg_quotes, const char *end_quotes)
{
   char *e;
   char *q;

   s = ast_strip(s);
   if ((q = strchr(beg_quotes, *s)) && *q != '\0') {
      e = s + strlen(s) - 1;
      if (*e == *(end_quotes + (q - beg_quotes))) {
         s++;
         *e = '\0';
      }
   }

   return s;
}

char *ast_strsep(char **iss, const char sep, uint32_t flags)
{
   char *st = *iss;
   char *is;
   int inquote = 0;
   int found = 0;
   char stack[8];

   if (ast_strlen_zero(st)) {
      return NULL;
   }

   memset(stack, 0, sizeof(stack));

   for(is = st; *is; is++) {
      if (*is == '\\') {
         if (*++is != '\0') {
            is++;
         } else {
            break;
         }
      }

      if (*is == '\'' || *is == '"') {
         if (*is == stack[inquote]) {
            stack[inquote--] = '\0';
         } else {
            if (++inquote >= sizeof(stack)) {
               return NULL;
            }
            stack[inquote] = *is;
         }
      }

      if (*is == sep && !inquote) {
         *is = '\0';
         found = 1;
         *iss = is + 1;
         break;
      }
   }
   if (!found) {
      *iss = NULL;
   }

   if (flags & AST_STRSEP_STRIP) {
      st = ast_strip_quoted(st, "'\"", "'\"");
   }

   if (flags & AST_STRSEP_TRIM) {
      st = ast_strip(st);
   }

   if (flags & AST_STRSEP_UNESCAPE) {
      ast_unescape_quoted(st);
   }

   return st;
}

char *ast_unescape_semicolon(char *s)
{
   char *e;
   char *work = s;

   while ((e = strchr(work, ';'))) {
      if ((e > work) && (*(e-1) == '\\')) {
         memmove(e - 1, e, strlen(e) + 1);
         work = e;
      } else {
         work = e + 1;
      }
   }

   return s;
}

/* !\brief unescape some C sequences in place, return pointer to the original string.
 */
char *ast_unescape_c(char *src)
{
   char c, *ret, *dst;

   if (src == NULL)
      return NULL;
   for (ret = dst = src; (c = *src++); *dst++ = c ) {
      if (c != '\\')
         continue;   /* copy char at the end of the loop */
      switch ((c = *src++)) {
      case '\0':  /* special, trailing '\' */
         c = '\\';
         break;
      case 'b':   /* backspace */
         c = '\b';
         break;
      case 'f':   /* form feed */
         c = '\f';
         break;
      case 'n':
         c = '\n';
         break;
      case 'r':
         c = '\r';
         break;
      case 't':
         c = '\t';
         break;
      }
      /* default, use the char literally */
   }
   *dst = '\0';
   return ret;
}

/*
 * Standard escape sequences - Note, '\0' is not included as a valid character
 * to escape, but instead is used here as a NULL terminator for the string.
 */
char escape_sequences[] = {
   '\a', '\b', '\f', '\n', '\r', '\t', '\v', '\\', '\'', '\"', '\?', '\0'
};

/*
 * Standard escape sequences output map (has to maintain matching order with
 * escape_sequences). '\0' is included here as a NULL terminator for the string.
 */
static char escape_sequences_map[] = {
   'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', '\'', '"', '?', '\0'
};

char *ast_escape(char *dest, const char *s, size_t size, const char *to_escape)
{
   char *p;
   char *c;

   if (!dest || !size) {
      return dest;
   }
   if (ast_strlen_zero(s)) {
      *dest = '\0';
      return dest;
   }

   if (ast_strlen_zero(to_escape)) {
      ast_copy_string(dest, s, size);
      return dest;
   }

   for (p = dest; *s && --size; ++s, ++p) {
      /* If in the list of characters to escape then escape it */
      if (strchr(to_escape, *s)) {
         if (!--size) {
            /* Not enough room left for the escape sequence. */
            break;
         }

         /*
          * See if the character to escape is part of the standard escape
          * sequences. If so we'll have to use its mapped counterpart
          * otherwise just use the current character.
          */
         c = strchr(escape_sequences, *s);
         *p++ = '\\';
         *p = c ? escape_sequences_map[c - escape_sequences] : *s;
      } else {
         *p = *s;
      }
   }
   *p = '\0';

   return dest;
}

char *ast_escape_c(char *dest, const char *s, size_t size)
{
   /*
    * Note - This is an optimized version of ast_escape. When looking only
    * for escape_sequences a couple of checks used in the generic case can
    * be left out thus making it slightly more efficient.
    */
   char *p;
   char *c;

   if (!dest || !size) {
      return dest;
   }
   if (ast_strlen_zero(s)) {
      *dest = '\0';
      return dest;
   }

   for (p = dest; *s && --size; ++s, ++p) {
      /*
       * See if the character to escape is part of the standard escape
       * sequences. If so use its mapped counterpart.
       */
      c = strchr(escape_sequences, *s);
      if (c) {
         if (!--size) {
            /* Not enough room left for the escape sequence. */
            break;
         }

         *p++ = '\\';
         *p = escape_sequences_map[c - escape_sequences];
      } else {
         *p = *s;
      }
   }
   *p = '\0';

   return dest;
}

static char *escape_alloc(const char *s, size_t *size)
{
   if (!s) {
      return NULL;
   }

   /*
    * The result string needs to be twice the size of the given
    * string just in case every character in it needs to be escaped.
    */
   *size = strlen(s) * 2 + 1;
   return ast_malloc(*size);
}

char *ast_escape_alloc(const char *s, const char *to_escape)
{
   size_t size = 0;
   char *dest = escape_alloc(s, &size);

   return ast_escape(dest, s, size, to_escape);
}

char *ast_escape_c_alloc(const char *s)
{
   size_t size = 0;
   char *dest = escape_alloc(s, &size);

   return ast_escape_c(dest, s, size);
}

int ast_build_string_va(char **buffer, size_t *space, const char *fmt, va_list ap)
{
   int result;

   if (!buffer || !*buffer || !space || !*space)
      return -1;

   result = vsnprintf(*buffer, *space, fmt, ap);

   if (result < 0)
      return -1;
   else if (result > *space)
      result = *space;

   *buffer += result;
   *space -= result;
   return 0;
}

int ast_build_string(char **buffer, size_t *space, const char *fmt, ...)
{
   va_list ap;
   int result;

   va_start(ap, fmt);
   result = ast_build_string_va(buffer, space, fmt, ap);
   va_end(ap);

   return result;
}

int ast_regex_string_to_regex_pattern(const char *regex_string, struct ast_str **regex_pattern)
{
   int regex_len = strlen(regex_string);
   int ret = 3;

   /* Chop off the leading / if there is one */
   if ((regex_len >= 1) && (regex_string[0] == '/')) {
      ast_str_set(regex_pattern, 0, "%s", regex_string + 1);
      ret -= 2;
   }

   /* Chop off the ending / if there is one */
   if ((regex_len > 1) && (regex_string[regex_len - 1] == '/')) {
      ast_str_truncate(*regex_pattern, -1);
      ret -= 1;
   }

   return ret;
}

int ast_true(const char *s)
{
   if (ast_strlen_zero(s))
      return 0;

   /* Determine if this is a true value */
   if (!strcasecmp(s, "yes") ||
       !strcasecmp(s, "true") ||
       !strcasecmp(s, "y") ||
       !strcasecmp(s, "t") ||
       !strcasecmp(s, "1") ||
       !strcasecmp(s, "on"))
      return -1;

   return 0;
}

int ast_false(const char *s)
{
   if (ast_strlen_zero(s))
      return 0;

   /* Determine if this is a false value */
   if (!strcasecmp(s, "no") ||
       !strcasecmp(s, "false") ||
       !strcasecmp(s, "n") ||
       !strcasecmp(s, "f") ||
       !strcasecmp(s, "0") ||
       !strcasecmp(s, "off"))
      return -1;

   return 0;
}

#define ONE_MILLION  1000000
/*
 * put timeval in a valid range. usec is 0..999999
 * negative values are not allowed and truncated.
 */
static struct timeval tvfix(struct timeval a)
{
   if (a.tv_usec >= ONE_MILLION) {
      ast_log(LOG_WARNING, "warning too large timestamp %ld.%ld\n",
         (long)a.tv_sec, (long int) a.tv_usec);
      a.tv_sec += a.tv_usec / ONE_MILLION;
      a.tv_usec %= ONE_MILLION;
   } else if (a.tv_usec < 0) {
      ast_log(LOG_WARNING, "warning negative timestamp %ld.%ld\n",
         (long)a.tv_sec, (long int) a.tv_usec);
      a.tv_usec = 0;
   }
   return a;
}

struct timeval ast_tvadd(struct timeval a, struct timeval b)
{
   /* consistency checks to guarantee usec in 0..999999 */
   a = tvfix(a);
   b = tvfix(b);
   a.tv_sec += b.tv_sec;
   a.tv_usec += b.tv_usec;
   if (a.tv_usec >= ONE_MILLION) {
      a.tv_sec++;
      a.tv_usec -= ONE_MILLION;
   }
   return a;
}

struct timeval ast_tvsub(struct timeval a, struct timeval b)
{
   /* consistency checks to guarantee usec in 0..999999 */
   a = tvfix(a);
   b = tvfix(b);
   a.tv_sec -= b.tv_sec;
   a.tv_usec -= b.tv_usec;
   if (a.tv_usec < 0) {
      a.tv_sec-- ;
      a.tv_usec += ONE_MILLION;
   }
   return a;
}

int ast_remaining_ms(struct timeval start, int max_ms)
{
   int ms;

   if (max_ms < 0) {
      ms = max_ms;
   } else {
      ms = max_ms - ast_tvdiff_ms(ast_tvnow(), start);
      if (ms < 0) {
         ms = 0;
      }
   }

   return ms;
}

void ast_format_duration_hh_mm_ss(int duration, char *buf, size_t length)
{
   int durh, durm, durs;
   durh = duration / 3600;
   durm = (duration % 3600) / 60;
   durs = duration % 60;
   snprintf(buf, length, "%02d:%02d:%02d", durh, durm, durs);
}

#undef ONE_MILLION

#ifndef linux
AST_MUTEX_DEFINE_STATIC(randomlock);
#endif

long int ast_random(void)
{
   long int res;

   if (dev_urandom_fd >= 0) {
      int read_res = read(dev_urandom_fd, &res, sizeof(res));
      if (read_res > 0) {
         long int rm = RAND_MAX;
         res = res < 0 ? ~res : res;
         rm++;
         return res % rm;
      }
   }

   /* XXX - Thread safety really depends on the libc, not the OS.
    *
    * But... popular Linux libc's (uClibc, glibc, eglibc), all have a
    * somewhat thread safe random(3) (results are random, but not
    * reproducible). The libc's for other systems (BSD, et al.), not so
    * much.
    */
#ifdef linux
   res = random();
#else
   ast_mutex_lock(&randomlock);
   res = random();
   ast_mutex_unlock(&randomlock);
#endif
   return res;
}

void ast_replace_subargument_delimiter(char *s)
{
   for (; *s; s++) {
      if (*s == '^') {
         *s = ',';
      }
   }
}

char *ast_process_quotes_and_slashes(char *start, char find, char replace_with)
{
   char *dataPut = start;
   int inEscape = 0;
   int inQuotes = 0;

   for (; *start; start++) {
      if (inEscape) {
         *dataPut++ = *start;       /* Always goes verbatim */
         inEscape = 0;
      } else {
         if (*start == '\\') {
            inEscape = 1;      /* Do not copy \ into the data */
         } else if (*start == '\'') {
            inQuotes = 1 - inQuotes;   /* Do not copy ' into the data */
         } else {
            /* Replace , with |, unless in quotes */
            *dataPut++ = inQuotes ? *start : ((*start == find) ? replace_with : *start);
         }
      }
   }
   if (start != dataPut)
      *dataPut = 0;
   return dataPut;
}

void ast_join_delim(char *s, size_t len, const char * const w[], unsigned int size, char delim)
{
   int x, ofs = 0;
   const char *src;

   /* Join words into a string */
   if (!s)
      return;
   for (x = 0; ofs < len && x < size && w[x] ; x++) {
      if (x > 0)
         s[ofs++] = delim;
      for (src = w[x]; *src && ofs < len; src++)
         s[ofs++] = *src;
   }
   if (ofs == len)
      ofs--;
   s[ofs] = '\0';
}

char *ast_to_camel_case_delim(const char *s, const char *delim)
{
   char *res = ast_strdup(s);
   char *front, *back, *buf = res;
   int size;

   front = strtok_r(buf, delim, &back);

   while (front) {
      size = strlen(front);
      *front = toupper(*front);
      ast_copy_string(buf, front, size + 1);
      buf += size;
      front = strtok_r(NULL, delim, &back);
   }

   return res;
}

/*! \brief
 * get values from config variables.
 */
int ast_get_timeval(const char *src, struct timeval *dst, struct timeval _default, int *consumed)
{
   long double dtv = 0.0;
   int scanned;

   if (dst == NULL)
      return -1;

   *dst = _default;

   if (ast_strlen_zero(src))
      return -1;

   /* only integer at the moment, but one day we could accept more formats */
   if (sscanf(src, "%30Lf%n", &dtv, &scanned) > 0) {
      dst->tv_sec = dtv;
      dst->tv_usec = (dtv - dst->tv_sec) * 1000000.0;
      if (consumed)
         *consumed = scanned;
      return 0;
   } else
      return -1;
}

/*! \brief
 * get values from config variables.
 */
int ast_get_time_t(const char *src, time_t *dst, time_t _default, int *consumed)
{
   long t;
   int scanned;

   if (dst == NULL)
      return -1;

   *dst = _default;

   if (ast_strlen_zero(src))
      return -1;

   /* only integer at the moment, but one day we could accept more formats */
   if (sscanf(src, "%30ld%n", &t, &scanned) == 1) {
      *dst = t;
      if (consumed)
         *consumed = scanned;
      return 0;
   } else
      return -1;
}

void ast_enable_packet_fragmentation(int sock)
{
#if defined(HAVE_IP_MTU_DISCOVER)
   int val = IP_PMTUDISC_DONT;

   if (setsockopt(sock, IPPROTO_IP, IP_MTU_DISCOVER, &val, sizeof(val)))
      ast_log(LOG_WARNING, "Unable to disable PMTU discovery. Large UDP packets may fail to be delivered when sent from this socket.\n");
#endif /* HAVE_IP_MTU_DISCOVER */
}

int ast_mkdir(const char *path, int mode)
{
   char *ptr;
   int len = strlen(path), count = 0, x, piececount = 0;
   char *tmp = ast_strdupa(path);
   char **pieces;
   char *fullpath = ast_alloca(len + 1);
   int res = 0;

   for (ptr = tmp; *ptr; ptr++) {
      if (*ptr == '/')
         count++;
   }

   /* Count the components to the directory path */
   pieces = ast_alloca(count * sizeof(*pieces));
   for (ptr = tmp; *ptr; ptr++) {
      if (*ptr == '/') {
         *ptr = '\0';
         pieces[piececount++] = ptr + 1;
      }
   }

   *fullpath = '\0';
   for (x = 0; x < piececount; x++) {
      /* This looks funky, but the buffer is always ideally-sized, so it's fine. */
      strcat(fullpath, "/");
      strcat(fullpath, pieces[x]);
      res = mkdir(fullpath, mode);
      if (res && errno != EEXIST)
         return errno;
   }
   return 0;
}

static int safe_mkdir(const char *base_path, char *path, int mode)
{
   RAII_VAR(char *, absolute_path, NULL, ast_std_free);

   absolute_path = realpath(path, NULL);

   if (absolute_path) {
      /* Path exists, but is it in the right place? */
      if (!ast_begins_with(absolute_path, base_path)) {
         return EPERM;
      }

      /* It is in the right place! */
      return 0;
   } else {
      /* Path doesn't exist. */

      /* The slash terminating the subpath we're checking */
      char *path_term = strchr(path, '/');
      /* True indicates the parent path is within base_path */
      int parent_is_safe = 0;
      int res;

      while (path_term) {
         RAII_VAR(char *, absolute_subpath, NULL, ast_std_free);

         /* Truncate the path one past the slash */
         char c = *(path_term + 1);
         *(path_term + 1) = '\0';
         absolute_subpath = realpath(path, NULL);

         if (absolute_subpath) {
            /* Subpath exists, but is it safe? */
            parent_is_safe = ast_begins_with(
               absolute_subpath, base_path);
         } else if (parent_is_safe) {
            /* Subpath does not exist, but parent is safe
             * Create it */
            res = mkdir(path, mode);
            if (res != 0) {
               ast_assert(errno != EEXIST);
               return errno;
            }
         } else {
            /* Subpath did not exist, parent was not safe
             * Fail! */
            errno = EPERM;
            return errno;
         }
         /* Restore the path */
         *(path_term + 1) = c;
         /* Move on to the next slash */
         path_term = strchr(path_term + 1, '/');
      }

      /* Now to build the final path, but only if it's safe */
      if (!parent_is_safe) {
         errno = EPERM;
         return errno;
      }

      res = mkdir(path, mode);
      if (res != 0 && errno != EEXIST) {
         return errno;
      }

      return 0;
   }
}

int ast_safe_mkdir(const char *base_path, const char *path, int mode)
{
   RAII_VAR(char *, absolute_base_path, NULL, ast_std_free);
   RAII_VAR(char *, p, NULL, ast_free);

   if (base_path == NULL || path == NULL) {
      errno = EFAULT;
      return errno;
   }

   p = ast_strdup(path);
   if (p == NULL) {
      errno = ENOMEM;
      return errno;
   }

   absolute_base_path = realpath(base_path, NULL);
   if (absolute_base_path == NULL) {
      return errno;
   }

   return safe_mkdir(absolute_base_path, p, mode);
}

static void utils_shutdown(void)
{
   close(dev_urandom_fd);
   dev_urandom_fd = -1;
#if defined(DEBUG_THREADS) && !defined(LOW_MEMORY)
   ast_cli_unregister_multiple(utils_cli, ARRAY_LEN(utils_cli));
#endif
}

int ast_utils_init(void)
{
   dev_urandom_fd = open("/dev/urandom", O_RDONLY);
   base64_init();
#ifdef DEBUG_THREADS
#if !defined(LOW_MEMORY)
   ast_cli_register_multiple(utils_cli, ARRAY_LEN(utils_cli));
#endif
#endif
   ast_register_cleanup(utils_shutdown);
   return 0;
}


/*!
 *\brief Parse digest authorization header.
 *\return Returns -1 if we have no auth or something wrong with digest.
 *\note  This function may be used for Digest request and responce header.
 * request arg is set to nonzero, if we parse Digest Request.
 * pedantic arg can be set to nonzero if we need to do addition Digest check.
 */
int ast_parse_digest(const char *digest, struct ast_http_digest *d, int request, int pedantic) {
   char *c;
   struct ast_str *str = ast_str_create(16);

   /* table of recognised keywords, and places where they should be copied */
   const struct x {
      const char *key;
      const ast_string_field *field;
   } *i, keys[] = {
      { "username=", &d->username },
      { "realm=", &d->realm },
      { "nonce=", &d->nonce },
      { "uri=", &d->uri },
      { "domain=", &d->domain },
      { "response=", &d->response },
      { "cnonce=", &d->cnonce },
      { "opaque=", &d->opaque },
      /* Special cases that cannot be directly copied */
      { "algorithm=", NULL },
      { "qop=", NULL },
      { "nc=", NULL },
      { NULL, 0 },
   };

   if (ast_strlen_zero(digest) || !d || !str) {
      ast_free(str);
      return -1;
   }

   ast_str_set(&str, 0, "%s", digest);

   c = ast_skip_blanks(ast_str_buffer(str));

   if (strncasecmp(c, "Digest ", strlen("Digest "))) {
      ast_log(LOG_WARNING, "Missing Digest.\n");
      ast_free(str);
      return -1;
   }
   c += strlen("Digest ");

   /* lookup for keys/value pair */
   while (c && *c && *(c = ast_skip_blanks(c))) {
      /* find key */
      for (i = keys; i->key != NULL; i++) {
         char *src, *separator;
         int unescape = 0;
         if (strncasecmp(c, i->key, strlen(i->key)) != 0) {
            continue;
         }

         /* Found. Skip keyword, take text in quotes or up to the separator. */
         c += strlen(i->key);
         if (*c == '"') {
            src = ++c;
            separator = "\"";
            unescape = 1;
         } else {
            src = c;
            separator = ",";
         }
         strsep(&c, separator); /* clear separator and move ptr */
         if (unescape) {
            ast_unescape_c(src);
         }
         if (i->field) {
            ast_string_field_ptr_set(d, i->field, src);
         } else {
            /* Special cases that require additional procesing */
            if (!strcasecmp(i->key, "algorithm=")) {
               if (strcasecmp(src, "MD5")) {
                  ast_log(LOG_WARNING, "Digest algorithm: \"%s\" not supported.\n", src);
                  ast_free(str);
                  return -1;
               }
            } else if (!strcasecmp(i->key, "qop=") && !strcasecmp(src, "auth")) {
               d->qop = 1;
            } else if (!strcasecmp(i->key, "nc=")) {
               unsigned long u;
               if (sscanf(src, "%30lx", &u) != 1) {
                  ast_log(LOG_WARNING, "Incorrect Digest nc value: \"%s\".\n", src);
                  ast_free(str);
                  return -1;
               }
               ast_string_field_set(d, nc, src);
            }
         }
         break;
      }
      if (i->key == NULL) { /* not found, try ',' */
         strsep(&c, ",");
      }
   }
   ast_free(str);

   /* Digest checkout */
   if (ast_strlen_zero(d->realm) || ast_strlen_zero(d->nonce)) {
      /* "realm" and "nonce" MUST be always exist */
      return -1;
   }

   if (!request) {
      /* Additional check for Digest response */
      if (ast_strlen_zero(d->username) || ast_strlen_zero(d->uri) || ast_strlen_zero(d->response)) {
         return -1;
      }

      if (pedantic && d->qop && (ast_strlen_zero(d->cnonce) || ast_strlen_zero(d->nc))) {
         return -1;
      }
   }

   return 0;
}

int ast_get_tid(void)
{
   int ret = -1;
#if defined (__linux) && defined(SYS_gettid)
   ret = syscall(SYS_gettid); /* available since Linux 1.4.11 */
#elif defined(__sun)
   ret = pthread_self();
#elif defined(__APPLE__)
   ret = mach_thread_self();
   mach_port_deallocate(mach_task_self(), ret);
#elif defined(__FreeBSD__) && defined(HAVE_SYS_THR_H)
   long lwpid;
   thr_self(&lwpid); /* available since sys/thr.h creation 2003 */
   ret = lwpid;
#endif
   return ret;
}

char *ast_utils_which(const char *binary, char *fullpath, size_t fullpath_size)
{
   const char *envPATH = getenv("PATH");
   char *tpath, *path;
   struct stat unused;
   if (!envPATH) {
      return NULL;
   }
   tpath = ast_strdupa(envPATH);
   while ((path = strsep(&tpath, ":"))) {
      snprintf(fullpath, fullpath_size, "%s/%s", path, binary);
      if (!stat(fullpath, &unused)) {
         return fullpath;
      }
   }
   return NULL;
}

int ast_check_ipv6(void)
{
   int udp6_socket = socket(AF_INET6, SOCK_DGRAM, 0);

   if (udp6_socket < 0) {
      return 0;
   }

   close(udp6_socket);
   return 1;
}

void DO_CRASH_NORETURN ast_do_crash(void)
{
#if defined(DO_CRASH)
   abort();
   /*
    * Just in case abort() doesn't work or something else super
    * silly, and for Qwell's amusement.
    */
   *((int *) 0) = 0;
#endif   /* defined(DO_CRASH) */
}

void DO_CRASH_NORETURN __ast_assert_failed(int condition, const char *condition_str, const char *file, int line, const char *function)
{
   /*
    * Attempt to put it into the logger, but hope that at least
    * someone saw the message on stderr ...
    */
   fprintf(stderr, "FRACK!, Failed assertion %s (%d) at line %d in %s of %s\n",
      condition_str, condition, line, function, file);
   ast_log(__LOG_ERROR, file, line, function, "FRACK!, Failed assertion %s (%d)\n",
      condition_str, condition);

   /* Generate a backtrace for the assert */
   ast_log_backtrace();

   /*
    * Give the logger a chance to get the message out, just in case
    * we abort(), or Asterisk crashes due to whatever problem just
    * happened after we exit ast_assert().
    */
   usleep(1);
   ast_do_crash();
}

char *ast_eid_to_str(char *s, int maxlen, struct ast_eid *eid)
{
   int x;
   char *os = s;
   if (maxlen < 18) {
      if (s && (maxlen > 0)) {
         *s = '\0';
      }
   } else {
      for (x = 0; x < 5; x++) {
         sprintf(s, "%02hhx:", eid->eid[x]);
         s += 3;
      }
      sprintf(s, "%02hhx", eid->eid[5]);
   }
   return os;
}

#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__) || defined(__Darwin__)
#include <ifaddrs.h>
#include <net/if_dl.h>

void ast_set_default_eid(struct ast_eid *eid)
{
   struct ifaddrs *ifap, *ifaphead;
   int rtnerr;
   const struct sockaddr_dl *sdl;
   int alen;
   caddr_t ap;
   char eid_str[20];
   unsigned char empty_mac[6] = {0, 0, 0, 0, 0, 0};
   unsigned char full_mac[6]  = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

   rtnerr = getifaddrs(&ifaphead);
   if (rtnerr) {
      ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
         "You will have to set it manually.\n");
      return;
   }

   if (!ifaphead) {
      ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
         "You will have to set it manually.\n");
      return;
   }

   for (ifap = ifaphead; ifap; ifap = ifap->ifa_next) {
      if (ifap->ifa_addr->sa_family != AF_LINK) {
         continue;
      }

      sdl = (const struct sockaddr_dl *) ifap->ifa_addr;
      ap = ((caddr_t) ((sdl)->sdl_data + (sdl)->sdl_nlen));
      alen = sdl->sdl_alen;
      if (alen != 6 || !(memcmp(ap, &empty_mac, 6) && memcmp(ap, &full_mac, 6))) {
         continue;
      }

      memcpy(eid, ap, sizeof(*eid));
      ast_debug(1, "Seeding global EID '%s'\n",
            ast_eid_to_str(eid_str, sizeof(eid_str), eid));
      freeifaddrs(ifaphead);
      return;
   }

   ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
      "You will have to set it manually.\n");
   freeifaddrs(ifaphead);

   return;
}

#elif defined(SOLARIS)
#include <sys/sockio.h>
#include <net/if_arp.h>

void ast_set_default_eid(struct ast_eid *eid)
{
   int s;
   int x;
   struct lifreq *ifr = NULL;
   struct lifnum ifn;
   struct lifconf ifc;
   struct arpreq ar;
   struct sockaddr_in *sa, *sa2;
   char *buf = NULL;
   char eid_str[20];
   int bufsz;
   unsigned char empty_mac[6] = {0, 0, 0, 0, 0, 0};
   unsigned char full_mac[6]  = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

   s = socket(AF_INET, SOCK_STREAM, 0);
   if (s <= 0) {
      ast_log(LOG_WARNING, "Unable to open a socket for seeding global EID. "
         " You will have to set it manually.\n");
      return;
   }

   /* Get a count of interfaces on the machine */
   ifn.lifn_family = AF_UNSPEC;
   ifn.lifn_flags = 0;
   ifn.lifn_count = 0;
   if (ioctl(s, SIOCGLIFNUM, &ifn) < 0) {
      ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
         " You will have to set it manually.\n");
      close(s);
      return;
   }

   bufsz = ifn.lifn_count * sizeof(struct lifreq);
   if (!(buf = ast_malloc(bufsz))) {
      ast_log(LOG_WARNING, "Unable to allocate memory for seeding global EID. "
         "You will have to set it manually.\n");
      close(s);
      return;
   }
   memset(buf, 0, bufsz);

   /* Get a list of interfaces on the machine */
   ifc.lifc_len = bufsz;
   ifc.lifc_buf = buf;
   ifc.lifc_family = AF_UNSPEC;
   ifc.lifc_flags = 0;
   if (ioctl(s, SIOCGLIFCONF, &ifc) < 0) {
      ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
         "You will have to set it manually.\n");
      ast_free(buf);
      close(s);
      return;
   }

   for (ifr = (struct lifreq *)buf, x = 0; x < ifn.lifn_count; ifr++, x++) {
      unsigned char *p;

      sa = (struct sockaddr_in *)&(ifr->lifr_addr);
      sa2 = (struct sockaddr_in *)&(ar.arp_pa);
      *sa2 = *sa;

      if(ioctl(s, SIOCGARP, &ar) >= 0) {
         p = (unsigned char *)&(ar.arp_ha.sa_data);
         if (!(memcmp(p, &empty_mac, 6) && memcmp(p, &full_mac, 6))) {
            continue;
         }

         memcpy(eid, p, sizeof(*eid));
         ast_debug(1, "Seeding global EID '%s'\n",
            ast_eid_to_str(eid_str, sizeof(eid_str), eid));
         ast_free(buf);
         close(s);
         return;
      }
   }

   ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
      "You will have to set it manually.\n");
   ast_free(buf);
   close(s);

   return;
}

#else
void ast_set_default_eid(struct ast_eid *eid)
{
   int s;
   int i;
   struct ifreq *ifr;
   struct ifreq *ifrp;
   struct ifconf ifc;
   char *buf = NULL;
   char eid_str[20];
   int bufsz, num_interfaces;
   unsigned char empty_mac[6] = {0, 0, 0, 0, 0, 0};
   unsigned char full_mac[6]  = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

   s = socket(AF_INET, SOCK_STREAM, 0);
   if (s < 0) {
      ast_log(LOG_WARNING, "Unable to open socket for seeding global EID. "
         "You will have to set it manually.\n");
      return;
   }

   ifc.ifc_len = 0;
   ifc.ifc_buf = NULL;
   if (ioctl(s, SIOCGIFCONF, &ifc) || ifc.ifc_len <= 0) {
      ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
         "You will have to set it manually.\n");
      close(s);
      return;
   }
   bufsz = ifc.ifc_len;

   if (!(buf = ast_malloc(bufsz))) {
      ast_log(LOG_WARNING, "Unable to allocate memory for seeding global EID. "
         "You will have to set it manually.\n");
      close(s);
      return;
   }

   ifc.ifc_buf = buf;
   if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
      ast_log(LOG_WARNING, "Unable to retrieve ethernet interfaces for seeding global EID. "
         "You will have to set it manually.\n");
      ast_free(buf);
      close(s);
      return;
   }

   ifrp = ifc.ifc_req;
   num_interfaces = ifc.ifc_len / sizeof(*ifr);

   for (i = 0; i < num_interfaces; i++) {
      ifr = &ifrp[i];
      if (!ioctl(s, SIOCGIFHWADDR, ifr)) {
         unsigned char *hwaddr = (unsigned char *) ifr->ifr_hwaddr.sa_data;

         if (!(memcmp(hwaddr, &empty_mac, 6) && memcmp(hwaddr, &full_mac, 6))) {
            continue;
         }

         memcpy(eid, hwaddr, sizeof(*eid));
         ast_debug(1, "Seeding global EID '%s' from '%s' using 'siocgifhwaddr'\n",
            ast_eid_to_str(eid_str, sizeof(eid_str), eid), ifr->ifr_name);
         ast_free(buf);
         close(s);
         return;
      }
   }

   ast_log(LOG_WARNING, "No ethernet interface found for seeding global EID. "
      "You will have to set it manually.\n");
   ast_free(buf);
   close(s);

   return;
}
#endif /* LINUX */

int ast_str_to_eid(struct ast_eid *eid, const char *s)
{
   unsigned int eid_int[6];
   int x;

   if (sscanf(s, "%2x:%2x:%2x:%2x:%2x:%2x", &eid_int[0], &eid_int[1], &eid_int[2],
       &eid_int[3], &eid_int[4], &eid_int[5]) != 6) {
         return -1;
   }

   for (x = 0; x < 6; x++) {
      eid->eid[x] = eid_int[x];
   }

   return 0;
}

int ast_eid_cmp(const struct ast_eid *eid1, const struct ast_eid *eid2)
{
   return memcmp(eid1, eid2, sizeof(*eid1));
}

int ast_eid_is_empty(const struct ast_eid *eid)
{
   struct ast_eid empty_eid;

   memset(&empty_eid, 0, sizeof(empty_eid));
   return memcmp(eid, &empty_eid, sizeof(empty_eid)) ? 0 : 1;
}

int ast_file_is_readable(const char *filename)
{
#if defined(HAVE_EACCESS) || defined(HAVE_EUIDACCESS)
#if defined(HAVE_EUIDACCESS) && !defined(HAVE_EACCESS)
#define eaccess euidaccess
#endif
   return eaccess(filename, R_OK) == 0;
#else
   int fd = open(filename, O_RDONLY |  O_NONBLOCK);
   if (fd < 0) {
      return 0;
   }
   close(fd);
   return 1;
#endif
}

int ast_compare_versions(const char *version1, const char *version2)
{
   unsigned int major[2] = { 0 };
   unsigned int minor[2] = { 0 };
   unsigned int patch[2] = { 0 };
   unsigned int extra[2] = { 0 };
   int res;

   sscanf(version1, "%u.%u.%u.%u", &major[0], &minor[0], &patch[0], &extra[0]);
   sscanf(version2, "%u.%u.%u.%u", &major[1], &minor[1], &patch[1], &extra[1]);

   res = major[0] - major[1];
   if (res) {
      return res;
   }
   res = minor[0] - minor[1];
   if (res) {
      return res;
   }
   res = patch[0] - patch[1];
   if (res) {
      return res;
   }
   return extra[0] - extra[1];
}

int __ast_fd_set_flags(int fd, int flags, enum ast_fd_flag_operation op,
   const char *file, int lineno, const char *function)
{
   int f;

   f = fcntl(fd, F_GETFL);
   if (f == -1) {
      ast_log(__LOG_ERROR, file, lineno, function,
         "Failed to get fcntl() flags for file descriptor: %s\n", strerror(errno));
      return -1;
   }

   switch (op) {
   case AST_FD_FLAG_SET:
      if ((f & flags) == flags) {
         /* There is nothing to set */
         return 0;
      }
      f |= flags;
      break;
   case AST_FD_FLAG_CLEAR:
      if (!(f & flags)) {
         /* There is nothing to clear */
         return 0;
      }
      f &= ~flags;
      break;
   default:
      ast_assert(0);
      break;
   }

   f = fcntl(fd, F_SETFL, f);
   if (f == -1) {
      ast_log(__LOG_ERROR, file, lineno, function,
         "Failed to set fcntl() flags for file descriptor: %s\n", strerror(errno));
      return -1;
   }

   return 0;
}

#ifndef HAVE_SOCK_NONBLOCK
int ast_socket_nonblock(int domain, int type, int protocol)
{
   int s = socket(domain, type, protocol);
   if (s < 0) {
      return -1;
   }

   if (ast_fd_set_flags(s, O_NONBLOCK)) {
      close(s);
      return -1;
   }

   return s;
}
#endif

#ifndef HAVE_PIPE2
int ast_pipe_nonblock(int filedes[2])
{
   int p = pipe(filedes);
   if (p < 0) {
      return -1;
   }

   if (ast_fd_set_flags(filedes[0], O_NONBLOCK)
      || ast_fd_set_flags(filedes[1], O_NONBLOCK)) {
      close(filedes[0]);
      close(filedes[1]);
      return -1;
   }

   return 0;
}
#endif

/*!
 * \brief A thread local indicating whether the current thread is a user interface.
 */
AST_THREADSTORAGE(thread_user_interface_tl);

int ast_thread_user_interface_set(int is_user_interface)
{
   int *thread_user_interface;

   thread_user_interface = ast_threadstorage_get(
      &thread_user_interface_tl, sizeof(*thread_user_interface));
   if (thread_user_interface == NULL) {
      ast_log(LOG_ERROR, "Error setting user interface status for current thread\n");
      return -1;
   }

   *thread_user_interface = !!is_user_interface;
   return 0;
}

int ast_thread_is_user_interface(void)
{
   int *thread_user_interface;

   thread_user_interface = ast_threadstorage_get(
      &thread_user_interface_tl, sizeof(*thread_user_interface));
   if (thread_user_interface == NULL) {
      ast_log(LOG_ERROR, "Error checking thread's user interface status\n");
      /* On error, assume that we are not a user interface thread */
      return 0;
   }

   return *thread_user_interface;
}