io.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * 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 I/O Management (Derived from Cheops-NG)
 *
 * \author Mark Spencer <markster@digium.com>
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <termios.h>
#include <sys/ioctl.h>
 
#include "asterisk/io.h"
#include "asterisk/utils.h"
#ifdef HAVE_SYSTEMD
#include <systemd/sd-daemon.h>
 
#ifndef SD_LISTEN_FDS_START
#define SD_LISTEN_FDS_START 3
#endif
#endif
 
#ifdef DEBUG_IO
#define DEBUG DEBUG_M
#else
#define DEBUG(a)
#endif
 
/*! \brief
 * Kept for each file descriptor
 */
struct io_rec {
    ast_io_cb callback;     /*!< What is to be called */
    void *data;         /*!< Data to be passed */
    int *id;            /*!< ID number */
};
 
/* These two arrays are keyed with
   the same index.  it's too bad that
   pollfd doesn't have a callback field
   or something like that.  They grow as
   needed, by GROW_SHRINK_SIZE structures
   at once */
 
#define GROW_SHRINK_SIZE 512
 
/*! \brief Global IO variables are now in a struct in order to be
   made threadsafe */
struct io_context {
    struct pollfd *fds;           /*!< Poll structure */
    struct io_rec *ior;           /*!< Associated I/O records */
    unsigned int fdcnt;           /*!< First available fd */
    unsigned int maxfdcnt;        /*!< Maximum available fd */
    int current_ioc;              /*!< Currently used io callback */
    int needshrink;               /*!< Whether something has been deleted */
};
 
/*! \brief Create an I/O context */
struct io_context *io_context_create(void)
{
    struct io_context *tmp = NULL;
 
    if (!(tmp = ast_malloc(sizeof(*tmp))))
        return NULL;
 
    tmp->needshrink = 0;
    tmp->fdcnt = 0;
    tmp->maxfdcnt = GROW_SHRINK_SIZE/2;
    tmp->current_ioc = -1;
 
    if (!(tmp->fds = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->fds)))) {
        ast_free(tmp);
        tmp = NULL;
    } else {
        if (!(tmp->ior = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->ior)))) {
            ast_free(tmp->fds);
            ast_free(tmp);
            tmp = NULL;
        }
    }
 
    return tmp;
}
 
void io_context_destroy(struct io_context *ioc)
{
    /* Free associated memory with an I/O context */
    if (ioc->fds)
        ast_free(ioc->fds);
    if (ioc->ior)
        ast_free(ioc->ior);
 
    ast_free(ioc);
}
 
/*! \brief
 * Grow the size of our arrays.
 * \retval 0 on success
 * \retval -1 on failure
 */
static int io_grow(struct io_context *ioc)
{
    void *tmp;
 
    DEBUG(ast_debug(1, "io_grow()\n"));
 
    ioc->maxfdcnt += GROW_SHRINK_SIZE;
 
    if ((tmp = ast_realloc(ioc->ior, (ioc->maxfdcnt + 1) * sizeof(*ioc->ior)))) {
        ioc->ior = tmp;
        if ((tmp = ast_realloc(ioc->fds, (ioc->maxfdcnt + 1) * sizeof(*ioc->fds)))) {
            ioc->fds = tmp;
        } else {
            /*
             * Failed to allocate enough memory for the pollfd.  Not
             * really any need to shrink back the iorec's as we'll
             * probably want to grow them again soon when more memory
             * is available, and then they'll already be the right size
             */
            ioc->maxfdcnt -= GROW_SHRINK_SIZE;
            return -1;
        }
    } else {
        /*
         * Memory allocation failure.  We return to the old size, and
         * return a failure
         */
        ioc->maxfdcnt -= GROW_SHRINK_SIZE;
        return -1;
    }
 
    return 0;
}
 
/*! \brief
 * Add a new I/O entry for this file descriptor
 * with the given event mask, to call callback with
 * data as an argument.
 */
int *ast_io_add(struct io_context *ioc, int fd, ast_io_cb callback, short events, void *data)
{
    int *ret;
 
    DEBUG(ast_debug(1, "ast_io_add()\n"));
 
    if (ioc->fdcnt >= ioc->maxfdcnt) {
        /*
         * We don't have enough space for this entry.  We need to
         * reallocate maxfdcnt poll fd's and io_rec's, or back out now.
         */
        if (io_grow(ioc))
            return NULL;
    }
 
    /*
     * At this point, we've got sufficiently large arrays going
     * and we can make an entry for it in the pollfd and io_r
     * structures.
     */
    ioc->fds[ioc->fdcnt].fd = fd;
    ioc->fds[ioc->fdcnt].events = events;
    ioc->fds[ioc->fdcnt].revents = 0;
    ioc->ior[ioc->fdcnt].callback = callback;
    ioc->ior[ioc->fdcnt].data = data;
 
    if (!(ioc->ior[ioc->fdcnt].id = ast_malloc(sizeof(*ioc->ior[ioc->fdcnt].id)))) {
        /* Bonk if we couldn't allocate an int */
        return NULL;
    }
 
    *(ioc->ior[ioc->fdcnt].id) = ioc->fdcnt;
    ret = ioc->ior[ioc->fdcnt].id;
    ioc->fdcnt++;
 
    return ret;
}
 
int *ast_io_change(struct io_context *ioc, int *id, int fd, ast_io_cb callback, short events, void *data)
{
    /* If this id exceeds our file descriptor count it doesn't exist here */
    if (*id > ioc->fdcnt)
        return NULL;
 
    if (fd > -1)
        ioc->fds[*id].fd = fd;
    if (callback)
        ioc->ior[*id].callback = callback;
    if (events)
        ioc->fds[*id].events = events;
    if (data)
        ioc->ior[*id].data = data;
 
    return id;
}
 
static int io_shrink(struct io_context *ioc)
{
    int getfrom, putto = 0;
 
    /*
     * Bring the fields from the very last entry to cover over
     * the entry we are removing, then decrease the size of the
     * arrays by one.
     */
    for (getfrom = 0; getfrom < ioc->fdcnt; getfrom++) {
        if (ioc->ior[getfrom].id) {
            /* In use, save it */
            if (getfrom != putto) {
                ioc->fds[putto] = ioc->fds[getfrom];
                ioc->ior[putto] = ioc->ior[getfrom];
                *(ioc->ior[putto].id) = putto;
            }
            putto++;
        }
    }
    ioc->fdcnt = putto;
    ioc->needshrink = 0;
    /* FIXME: We should free some memory if we have lots of unused
       io structs */
    return 0;
}
 
int ast_io_remove(struct io_context *ioc, int *_id)
{
    int x;
 
    if (!_id) {
        ast_log(LOG_WARNING, "Asked to remove NULL?\n");
        return -1;
    }
 
    for (x = 0; x < ioc->fdcnt; x++) {
        if (ioc->ior[x].id == _id) {
            /* Free the int immediately and set to NULL so we know it's unused now */
            ast_free(ioc->ior[x].id);
            ioc->ior[x].id = NULL;
            ioc->fds[x].events = 0;
            ioc->fds[x].revents = 0;
            ioc->needshrink = 1;
            if (ioc->current_ioc == -1)
                io_shrink(ioc);
            return 0;
        }
    }
 
    ast_log(LOG_NOTICE, "Unable to remove unknown id %p\n", _id);
 
    return -1;
}
 
/*! \brief
 * Make the poll call, and call
 * the callbacks for anything that needs
 * to be handled
 */
int ast_io_wait(struct io_context *ioc, int howlong)
{
    int res, x, origcnt;
 
    DEBUG(ast_debug(1, "ast_io_wait()\n"));
 
    if ((res = ast_poll(ioc->fds, ioc->fdcnt, howlong)) <= 0) {
        return res;
    }
 
    /* At least one event tripped */
    origcnt = ioc->fdcnt;
    for (x = 0; x < origcnt; x++) {
        /* Yes, it is possible for an entry to be deleted and still have an
           event waiting if it occurs after the original calling id */
        if (ioc->fds[x].revents && ioc->ior[x].id) {
            /* There's an event waiting */
            ioc->current_ioc = *ioc->ior[x].id;
            if (ioc->ior[x].callback) {
                if (!ioc->ior[x].callback(ioc->ior[x].id, ioc->fds[x].fd, ioc->fds[x].revents, ioc->ior[x].data)) {
                    /* Time to delete them since they returned a 0 */
                    ast_io_remove(ioc, ioc->ior[x].id);
                }
            }
            ioc->current_ioc = -1;
        }
    }
 
    if (ioc->needshrink)
        io_shrink(ioc);
 
    return res;
}
 
void ast_io_dump(struct io_context *ioc)
{
    /*
     * Print some debugging information via
     * the logger interface
     */
    int x;
 
    ast_debug(1, "Asterisk IO Dump: %u entries, %u max entries\n", ioc->fdcnt, ioc->maxfdcnt);
    ast_debug(1, "================================================\n");
    ast_debug(1, "| ID    FD     Callback    Data        Events  |\n");
    ast_debug(1, "+------+------+-----------+-----------+--------+\n");
    for (x = 0; x < ioc->fdcnt; x++) {
        ast_debug(1, "| %.4d | %.4d | %p | %p | %.6x |\n",
                *ioc->ior[x].id,
                ioc->fds[x].fd,
                ioc->ior[x].callback,
                ioc->ior[x].data,
                (unsigned)ioc->fds[x].events);
    }
    ast_debug(1, "================================================\n");
}
 
/* Unrelated I/O functions */
 
int ast_hide_password(int fd)
{
    struct termios tios;
    int res;
    int old;
    if (!isatty(fd))
        return -1;
    res = tcgetattr(fd, &tios);
    if (res < 0)
        return -1;
    old = tios.c_lflag & (ECHO | ECHONL);
    tios.c_lflag &= ~ECHO;
    tios.c_lflag |= ECHONL;
    res = tcsetattr(fd, TCSAFLUSH, &tios);
    if (res < 0)
        return -1;
    return old;
}
 
int ast_restore_tty(int fd, int oldstate)
{
    int res;
    struct termios tios;
    if (oldstate < 0)
        return 0;
    res = tcgetattr(fd, &tios);
    if (res < 0)
        return -1;
    tios.c_lflag &= ~(ECHO | ECHONL);
    tios.c_lflag |= oldstate;
    res = tcsetattr(fd, TCSAFLUSH, &tios);
    if (res < 0)
        return -1;
    return 0;
}
 
int ast_get_termcols(int fd)
{
    struct winsize win;
    int cols = 0;
 
    if (!isatty(fd))
        return -1;
 
    if ( ioctl(fd, TIOCGWINSZ, &win) != -1 ) {
        if ( !cols && win.ws_col > 0 )
            cols = (int) win.ws_col;
    } else {
        /* assume 80 characters if the ioctl fails for some reason */
        cols = 80;
    }
 
    return cols;
}
 
int ast_sd_notify(const char *state) {
#ifdef HAVE_SYSTEMD
    return sd_notify(0, state);
#else
    return 0;
#endif
}
 
#ifdef HAVE_SYSTEMD
/*!
 * \internal \brief Check the type and sockaddr of a file descriptor.
 * \param fd File Descriptor to check.
 * \param type SOCK_STREAM or SOCK_DGRAM
 * \param addr The socket address to match.
 * \retval 0 if matching
 * \retval -1 if not matching
 */
static int ast_sd_is_socket_sockaddr(int fd, int type, const struct ast_sockaddr* addr)
{
    int canretry = 1;
    struct ast_sockaddr fd_addr;
    struct sockaddr ss;
    socklen_t ss_len;
 
    if (sd_is_socket(fd, AF_UNSPEC, type, 1) <= 0) {
        return -1;
    }
 
doretry:
    if (getsockname(fd, &ss, &ss_len) != 0) {
        return -1;
    }
 
    if (ss.sa_family == AF_UNSPEC && canretry) {
        /* An unknown bug can cause silent failure from
         * the first call to getsockname. */
        canretry = 0;
        goto doretry;
    }
 
    ast_sockaddr_copy_sockaddr(&fd_addr, &ss, ss_len);
 
    return ast_sockaddr_cmp(addr, &fd_addr);
}
#endif
 
int ast_sd_get_fd(int type, const struct ast_sockaddr *addr)
{
#ifdef HAVE_SYSTEMD
    int count = sd_listen_fds(0);
    int idx;
 
    for (idx = 0; idx < count; idx++) {
        if (!ast_sd_is_socket_sockaddr(idx + SD_LISTEN_FDS_START, type, addr)) {
            return idx + SD_LISTEN_FDS_START;
        }
    }
#endif
 
    return -1;
}
 
int ast_sd_get_fd_un(int type, const char *path)
{
#ifdef HAVE_SYSTEMD
    int count = sd_listen_fds(0);
    int idx;
 
    for (idx = 0; idx < count; idx++) {
        if (sd_is_socket_unix(idx + SD_LISTEN_FDS_START, type, 1, path, 0) > 0) {
            return idx + SD_LISTEN_FDS_START;
        }
    }
#endif
 
    return -1;
}