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 <[email protected]>
 *
 * This code is released by the author with no restrictions on usage.
 *
 */

/*! \file
 *
 * \brief Resource limits
 *
 * \author Tilghman Lesher <[email protected]>
 */

/*** 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");