res_limit.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Resource limits
 *
 * Copyright (c) 2006 Tilghman Lesher.  All rights reserved.
 *
 * Tilghman Lesher <res_limit_200607@the-tilghman.com>
 *
 * This code is released by the author with no restrictions on usage.
 *
 */
 
/*! \file
 *
 * \brief Resource limits
 *
 * \author Tilghman Lesher <res_limit_200607@the-tilghman.com>
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <ctype.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "asterisk/module.h"
#include "asterisk/cli.h"
 
/* Find proper rlimit for virtual memory */
#ifdef RLIMIT_AS
#define VMEM_DEF RLIMIT_AS
#else
#ifdef RLIMIT_VMEM
#define VMEM_DEF RLIMIT_VMEM
#endif
#endif
 
static const struct limits {
    int resource;
    char limit[3];
    char desc[40];
    char clicmd[15];
} limits[] = {
    { RLIMIT_CPU,     "-t", "cpu time", "time" },
    { RLIMIT_FSIZE,   "-f", "file size" , "file" },
    { RLIMIT_DATA,    "-d", "program data segment", "data" },
    { RLIMIT_STACK,   "-s", "program stack size", "stack" },
    { RLIMIT_CORE,    "-c", "core file size", "core" },
#ifdef RLIMIT_RSS
    { RLIMIT_RSS,     "-m", "resident memory", "memory" },
    { RLIMIT_MEMLOCK, "-l", "amount of memory locked into RAM", "locked" },
#endif
#ifdef RLIMIT_NPROC
    { RLIMIT_NPROC,   "-u", "number of processes", "processes" },
#endif
    { RLIMIT_NOFILE,  "-n", "number of file descriptors", "descriptors" },
#ifdef VMEM_DEF
    { VMEM_DEF,       "-v", "virtual memory", "virtual" },
#endif
};
 
static int str2limit(const char *string)
{
    size_t i;
    for (i = 0; i < ARRAY_LEN(limits); i++) {
        if (!strcasecmp(string, limits[i].clicmd))
            return limits[i].resource;
    }
    return -1;
}
 
static const char *str2desc(const char *string)
{
    size_t i;
    for (i = 0; i < ARRAY_LEN(limits); i++) {
        if (!strcmp(string, limits[i].clicmd))
            return limits[i].desc;
    }
    return "<unknown>";
}
 
static char *complete_ulimit(struct ast_cli_args *a)
{
    int which = 0, i;
    int wordlen = strlen(a->word);
 
    if (a->pos > 1)
        return NULL;
    for (i = 0; i < ARRAY_LEN(limits); i++) {
        if (!strncasecmp(limits[i].clicmd, a->word, wordlen)) {
            if (++which > a->n)
                return ast_strdup(limits[i].clicmd);
        }
    }
    return NULL;
}
 
static char *handle_cli_ulimit(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
    int resource;
    struct rlimit rlimit = { 0, 0 };
 
    switch (cmd) {
    case CLI_INIT:
        e->command = "ulimit";
        e->usage =
            "Usage: ulimit {data|"
#ifdef RLIMIT_RSS
            "limit|"
#endif
            "file|"
#ifdef RLIMIT_RSS
            "memory|"
#endif
            "stack|time|"
#ifdef RLIMIT_NPROC
            "processes|"
#endif
#ifdef VMEM_DEF
            "virtual|"
#endif
            "core|descriptors} [<num>]\n"
            "       Shows or sets the corresponding resource limit.\n"
            "         data          Process data segment [readonly]\n"
#ifdef RLIMIT_RSS
            "         lock          Memory lock size [readonly]\n"
#endif
            "         file          File size\n"
#ifdef RLIMIT_RSS
            "         memory        Process resident memory [readonly]\n"
#endif
            "         stack         Process stack size [readonly]\n"
            "         time          CPU usage [readonly]\n"
#ifdef RLIMIT_NPROC
            "         processes     Child processes\n"
#endif
#ifdef VMEM_DEF
            "         virtual       Process virtual memory [readonly]\n"
#endif
            "         core          Core dump file size\n"
            "         descriptors   Number of file descriptors\n";
        return NULL;
    case CLI_GENERATE:
        return complete_ulimit(a);
    }
 
    if (a->argc > 3)
        return CLI_SHOWUSAGE;
 
    if (a->argc == 1) {
        char arg2[15];
        const char * const newargv[2] = { "ulimit", arg2 };
        for (resource = 0; resource < ARRAY_LEN(limits); resource++) {
            struct ast_cli_args newArgs = { .argv = newargv, .argc = 2 };
            ast_copy_string(arg2, limits[resource].clicmd, sizeof(arg2));
            handle_cli_ulimit(e, CLI_HANDLER, &newArgs);
        }
        return CLI_SUCCESS;
    } else {
        resource = str2limit(a->argv[1]);
        if (resource == -1) {
            ast_cli(a->fd, "Unknown resource\n");
            return CLI_FAILURE;
        }
 
        if (a->argc == 3) {
            int x;
#ifdef RLIMIT_NPROC
            if (resource != RLIMIT_NOFILE && resource != RLIMIT_CORE && resource != RLIMIT_NPROC && resource != RLIMIT_FSIZE) {
#else
            if (resource != RLIMIT_NOFILE && resource != RLIMIT_CORE && resource != RLIMIT_FSIZE) {
#endif
                ast_cli(a->fd, "Resource not permitted to be set\n");
                return CLI_FAILURE;
            }
 
            sscanf(a->argv[2], "%30d", &x);
            rlimit.rlim_max = rlimit.rlim_cur = x;
            setrlimit(resource, &rlimit);
            return CLI_SUCCESS;
        } else {
            if (!getrlimit(resource, &rlimit)) {
                char printlimit[32];
                const char *desc;
                if (rlimit.rlim_max == RLIM_INFINITY)
                    ast_copy_string(printlimit, "effectively unlimited", sizeof(printlimit));
                else
                    snprintf(printlimit, sizeof(printlimit), "limited to %d", (int) rlimit.rlim_cur);
                desc = str2desc(a->argv[1]);
                ast_cli(a->fd, "%c%s (%s) is %s.\n", toupper(desc[0]), desc + 1, a->argv[1], printlimit);
            } else
                ast_cli(a->fd, "Could not retrieve resource limits for %s: %s\n", str2desc(a->argv[1]), strerror(errno));
            return CLI_SUCCESS;
        }
    }
}
 
static struct ast_cli_entry cli_ulimit =
    AST_CLI_DEFINE(handle_cli_ulimit, "Set or show process resource limits");
 
static int unload_module(void)
{
    return ast_cli_unregister(&cli_ulimit);
}
 
static int load_module(void)
{
    return ast_cli_register(&cli_ulimit) ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Resource limits");