This file is ulimit.def, from which is created ulimit.c.
It implements the builtin "ulimit" in Bash.

Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 1, or (at your option) any later
version.

Bash is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with Bash; see the file COPYING.  If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

$PRODUCES ulimit.c

$BUILTIN ulimit
$FUNCTION ulimit_builtin
$DEPENDS_ON !MINIX
$SHORT_DOC ulimit [-SHacdflmnpstuv] [limit]
Ulimit provides control over the resources available to processes
started by the shell, on systems that allow such control.  If an
option is given, it is interpreted as follows:

    -S	use the `soft' resource limit
    -H	use the `hard' resource limit
    -a	all current limits are reported
    -c	the maximum size of core files created
    -d	the maximum size of a process's data segment
    -f	the maximum size of files created by the shell
    -l	the maximum size a process may lock into memory
    -m	the maximum resident set size
    -n	the maximum number of open file descriptors
    -p	the pipe buffer size
    -s	the maximum stack size
    -t	the maximum amount of cpu time in seconds
    -u	the maximum number of user processes
    -v	the size of virtual memory 

If LIMIT is given, it is the new value of the specified resource.
Otherwise, the current value of the specified resource is printed.
If no option is given, then -f is assumed.  Values are in 1024-byte
increments, except for -t, which is in seconds, -p, which is in
increments of 512 bytes, and -u, which is an unscaled number of
processes.
$END

#include <config.h>

#include "../bashtypes.h"
#include <sys/param.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <stdio.h>
#include <errno.h>

#include "../shell.h"
#include "common.h"
#include "bashgetopt.h"
#include "pipesize.h"

#if !defined (errno)
extern int errno;
#endif

/* For some reason, HPUX chose to make these definitions visible only if
   _KERNEL is defined, so we define _KERNEL before including <sys/resource.h>
   and #undef it afterward. */
#if defined (HAVE_RESOURCE)
#  include <sys/time.h>
#  if defined (HPUX) && defined (RLIMIT_NEEDS_KERNEL)
#    define _KERNEL
#  endif
#  include <sys/resource.h>
#  if defined (HPUX) && defined (RLIMIT_NEEDS_KERNEL)
#    undef _KERNEL
#  endif
#else
#  include <sys/times.h>
#endif

#if defined (HAVE_LIMITS_H)
#  include <limits.h>
#endif

/* Check for the most basic symbols.  If they aren't present, this
   system's <sys/resource.h> isn't very useful to us. */
#if !defined (RLIMIT_FSIZE) || !defined (HAVE_GETRLIMIT)
#  undef HAVE_RESOURCE
#endif

#if !defined (RLIMTYPE)
#  define RLIMTYPE long
#  define string_to_rlimtype string_to_long
#  define print_rlimtype(num, nl) printf ("%ld%s", num, nl ? "\n" : "")
#endif

#define DESCFMT	"%-28s"

/* Some systems use RLIMIT_NOFILE, others use RLIMIT_OFILE */
#if defined (HAVE_RESOURCE) && defined (RLIMIT_OFILE) && !defined (RLIMIT_NOFILE)
#  define RLIMIT_NOFILE RLIMIT_OFILE
#endif /* HAVE_RESOURCE && RLIMIT_OFILE && !RLIMIT_NOFILE */

/* Some systems have these, some do not. */
#ifdef RLIMIT_FSIZE
#  define RLIMIT_FILESIZE	RLIMIT_FSIZE
#else
#  define RLIMIT_FILESIZE	256
#endif

#define RLIMIT_PIPESIZE	257

#ifdef RLIMIT_NOFILE
#  define RLIMIT_OPENFILES	RLIMIT_NOFILE
#else
#  define RLIMIT_OPENFILES	258
#endif

#ifdef RLIMIT_VMEM
#  define RLIMIT_VIRTMEM	RLIMIT_VMEM
#  define RLIMIT_VMBLKSZ	1024
#else
#  ifdef RLIMIT_AS
#    define RLIMIT_VIRTMEM	RLIMIT_AS
#    define RLIMIT_VMBLKSZ	1024
#  else
#    define RLIMIT_VIRTMEM	259
#    define RLIMIT_VMBLKSZ	1
#  endif
#endif

#ifdef RLIMIT_NPROC
#  define RLIMIT_MAXUPROC	RLIMIT_NPROC
#else
#  define RLIMIT_MAXUPROC	260
#endif

#if !defined (RLIM_INFINITY)
#  define RLIM_INFINITY 0x7fffffff
#endif

#if !defined (RLIM_INVALID)
#  define RLIM_INVALID	(RLIMTYPE)-1
#endif

#define LIMIT_HARD 0x01
#define LIMIT_SOFT 0x02

static int ulimit_internal ();
static void printone ();
static void print_all_limits ();

static int get_limit ();
static int set_limit ();

static RLIMTYPE filesize ();
static RLIMTYPE pipesize ();
static RLIMTYPE getmaxuprc ();
static RLIMTYPE getmaxvm ();

typedef struct {
  int  option;			/* The ulimit option for this limit. */
  int  parameter;		/* Parameter to pass to get_limit (). */
  int  block_factor;		/* Blocking factor for specific limit. */
  char *description;		/* Descriptive string to output. */
} RESOURCE_LIMITS;

static RESOURCE_LIMITS limits[] = {
#ifdef RLIMIT_CORE
  { 'c',	RLIMIT_CORE,  1024, "core file size (blocks)" },
#endif
#ifdef RLIMIT_DATA
  { 'd',	RLIMIT_DATA,  1024, "data seg size (kbytes)" },
#endif
  { 'f',	RLIMIT_FILESIZE, 1024, "file size (blocks)" },
#ifdef RLIMIT_MEMLOCK
  { 'l',	RLIMIT_MEMLOCK, 1024, "max locked memory (kbytes)" },
#endif
#ifdef RLIMIT_RSS
  { 'm',	RLIMIT_RSS,   1024, "max memory size (kbytes)" },
#endif /* RLIMIT_RSS */
  { 'n',	RLIMIT_OPENFILES, 1, "open files" },
  { 'p',	RLIMIT_PIPESIZE, 512, "pipe size (512 bytes)" },
#ifdef RLIMIT_STACK
  { 's',	RLIMIT_STACK, 1024, "stack size (kbytes)" },
#endif
#ifdef RLIMIT_CPU
  { 't',	RLIMIT_CPU,      1, "cpu time (seconds)" },
#endif /* RLIMIT_CPU */
  { 'u',	RLIMIT_MAXUPROC, 1, "max user processes" },
#if defined (HAVE_RESOURCE)
  { 'v',	RLIMIT_VIRTMEM, RLIMIT_VMBLKSZ, "virtual memory (kbytes)" },
#endif
  { -1, -1, -1, (char *)NULL }
};
#define NCMDS	(sizeof(limits) / sizeof(limits[0]))

typedef struct _cmd {
  int cmd;
  char *arg;
} ULCMD;

static ULCMD *cmdlist;
static int ncmd;
static int cmdlistsz;

#if !defined (HAVE_RESOURCE) && !defined (HAVE_ULIMIT)
long
ulimit (cmd, newlim)
     int cmd;
     long newlim;
{
  errno = EINVAL;
  return -1;
}
#endif /* !HAVE_RESOURCE && !HAVE_ULIMIT */

static int
_findlim (opt)
     int opt;
{
  register int i;

  for (i = 0; limits[i].option > 0; i++)
    if (limits[i].option == opt)
      return i;
  return -1;
}

static char optstring[4 + 2 * NCMDS];

/* Report or set limits associated with certain per-process resources.
   See the help documentation in builtins.c for a full description. */
int
ulimit_builtin (list)
     register WORD_LIST *list;
{
  register char *s;
  int c, limind, mode, opt, all_limits;

  mode = 0;

  all_limits = 0;

  /* Idea stolen from pdksh -- build option string the first time called. */
  if (optstring[0] == 0)
    {
      s = optstring;
      *s++ = 'a'; *s++ = 'S'; *s++ = 'H';
      for (c = 0; limits[c].option > 0; c++)
	{
	  *s++ = limits[c].option;
	  *s++ = ';';
	}
      *s = '\0';
    }

  /* Initialize the command list. */
  if (cmdlistsz == 0)
    cmdlist = (ULCMD *)xmalloc ((cmdlistsz = 16) * sizeof (ULCMD));
  ncmd = 0;

  reset_internal_getopt ();
  while ((opt = internal_getopt (list, optstring)) != -1)
    {
      switch (opt)
	{
	case 'a':
	  all_limits++;
	  break;

	/* -S and -H are modifiers, not real options.  */
	case 'S':
	  mode |= LIMIT_SOFT;
	  break;

	case 'H':
	  mode |= LIMIT_HARD;
	  break;

	case '?':
	  builtin_usage ();
	  return (EX_USAGE);

	default:
	  if (ncmd >= cmdlistsz)
	    cmdlist = (ULCMD *)xrealloc (cmdlist, (cmdlistsz *= 2) * sizeof (ULCMD));
	  cmdlist[ncmd].cmd = opt;
	  cmdlist[ncmd++].arg = list_optarg;
	  break;
	}
    }
  list = loptend;

  if (all_limits)
    {
      print_all_limits (mode == 0 ? LIMIT_SOFT : mode);
      return (EXECUTION_SUCCESS);
    }

  /* default is `ulimit -f' */
  if (ncmd == 0)
    {
      cmdlist[ncmd].cmd = 'f';
      /* `ulimit something' is same as `ulimit -f something' */
      cmdlist[ncmd++].arg = list ? list->word->word : (char *)NULL;
      if (list)
	list = list->next;
    }

  /* verify each command in the list. */
  for (c = 0; c < ncmd; c++)
    {
      limind = _findlim (cmdlist[c].cmd);
      if (limind == -1)
	{
	  builtin_error ("bad command: `%c'", cmdlist[c].cmd);
	  return (EX_USAGE);
	}
    }

  for (c = 0; c < ncmd; c++)
    if (ulimit_internal (cmdlist[c].cmd, cmdlist[c].arg, mode, ncmd > 1) == EXECUTION_FAILURE)
      return (EXECUTION_FAILURE);

  return (EXECUTION_SUCCESS);
}

static int
ulimit_internal (cmd, cmdarg, mode, multiple)
     int cmd;
     char *cmdarg;
     int mode, multiple;
{
  int opt, limind, setting;
  long block_factor;
  RLIMTYPE current_limit, real_limit, limit;

  limit = RLIM_INVALID;
  setting = cmdarg != 0;
  limind = _findlim (cmd);
  if (mode == 0)
    mode = setting ? (LIMIT_HARD|LIMIT_SOFT) : LIMIT_SOFT;
  opt = get_limit (limind, mode, &current_limit);
  if (opt < 0)
    {
      builtin_error ("cannot get limit: %s", strerror (errno));
      return (EXECUTION_FAILURE);
    }

  if (setting == 0)	/* print the value of the specified limit */
    {
      printone (limind, current_limit, multiple);
      return (EXECUTION_SUCCESS);
    }
 
  /* Setting the limit. */
  if (STREQ (cmdarg, "unlimited"))
    limit = RLIM_INFINITY;
  else if (all_digits (cmdarg))
    limit = string_to_rlimtype (cmdarg);
  else
    {
      builtin_error ("bad non-numeric arg `%s'", cmdarg);
      return (EXECUTION_FAILURE);
    }

  block_factor = (limit == RLIM_INFINITY) ? 1 : limits[limind].block_factor;
  real_limit = limit * block_factor;

  if (real_limit < 0 || (real_limit == 0 && limit != 0))
    {
      builtin_error ("limit out of range: %d", limit);
      return (EXECUTION_FAILURE);
    }

  if (set_limit (limind, real_limit, mode) < 0)
    {
      builtin_error ("cannot modify limit: %s", strerror (errno));
      return (EXECUTION_FAILURE);
    }
  return (EXECUTION_SUCCESS);
}

static int
get_limit (ind, mode, limptr)
     int ind, mode;
     RLIMTYPE *limptr;
{
  RLIMTYPE value;
#if defined (HAVE_RESOURCE)
  struct rlimit limit;
#endif

  if (limits[ind].parameter >= 256)
    {
      switch (limits[ind].parameter)
	{
	case RLIMIT_FILESIZE:
	  value = filesize ();
	  break;
	case RLIMIT_PIPESIZE:
	  value = pipesize ();
	  break;
	case RLIMIT_OPENFILES:
	  value = (RLIMTYPE)getdtablesize ();
	  break;
	case RLIMIT_VIRTMEM:
	  value = getmaxvm (mode);
	  break;
	case RLIMIT_MAXUPROC:
	  value = getmaxuprc (mode);
	  break;
	default:
	  errno = EINVAL;
	  return -1;
	}
      *limptr = value;
      return ((value == RLIM_INVALID) ? -1 : 0);
    }
  else
    {
#if defined (HAVE_RESOURCE)
      if (getrlimit (limits[ind].parameter, &limit) < 0)
	return -1;
      value = (mode & LIMIT_SOFT) ? limit.rlim_cur : limit.rlim_max;
      *limptr = value;
      return 0;
#else
      errno = EINVAL;
      return -1;
#endif
    }
}

static int
set_limit (ind, newlim, mode)
     int ind;
     RLIMTYPE newlim;
     int mode;
{
#if defined (HAVE_RESOURCE)
   struct rlimit limit;
   RLIMTYPE val;
#endif

  if (limits[ind].parameter >= 256)
    switch (limits[ind].parameter)
      {
      case RLIMIT_FILESIZE:
#if !defined (HAVE_RESOURCE)
	return (ulimit (2, newlim / 512L));
#else
	errno = EINVAL;
	return -1;
#endif

      case RLIMIT_OPENFILES:
#if defined (HAVE_SETDTABLESIZE)
	return (setdtablesize (newlim));
#endif
      case RLIMIT_PIPESIZE:
      case RLIMIT_VIRTMEM:
      case RLIMIT_MAXUPROC:
      default:
	errno = EINVAL;
	return -1;
      }
  else
    {
#if defined (HAVE_RESOURCE)
      if (getrlimit (limits[ind].parameter, &limit) < 0)
	return -1;
      val = (current_user.euid != 0 && newlim == RLIM_INFINITY &&
	       (limit.rlim_cur <= limit.rlim_max))
		 ? limit.rlim_max : newlim;
      if (mode & LIMIT_SOFT)
	limit.rlim_cur = val;
      if (mode & LIMIT_HARD)
	limit.rlim_max = val;
	  
      return (setrlimit (limits[ind].parameter, &limit));
#else
      errno = EINVAL;
      return -1;
#endif
    }
}

static RLIMTYPE
getmaxvm (mode)
     int mode;
{
#if defined (HAVE_RESOURCE)
  struct rlimit rl;
  RLIMTYPE maxdata, maxstack;

  if (getrlimit (RLIMIT_DATA, &rl) < 0)
    return (RLIM_INVALID);
  else
    maxdata = (mode & LIMIT_SOFT) ? rl.rlim_cur : rl.rlim_max;

  if (getrlimit (RLIMIT_STACK, &rl) < 0)
    return (RLIM_INVALID);
  else
    maxstack = (mode & LIMIT_SOFT) ? rl.rlim_cur : rl.rlim_max;

  /* Protect against overflow. */
  return ((maxdata / 1024L) + (maxstack / 1024L));
#else
  errno = EINVAL;
  return RLIM_INVALID;
#endif /* HAVE_RESOURCE */
}

static RLIMTYPE
filesize()
{
#if !defined (HAVE_RESOURCE)
  return ((RLIMTYPE)ulimit (1, 0L));
#else
  errno = EINVAL;
  return RLIM_INVALID;
#endif
}

static RLIMTYPE
pipesize ()
{
#if defined (PIPE_BUF)
  /* This is defined on Posix systems. */
  return ((RLIMTYPE) PIPE_BUF);
#else
#  if defined (PIPESIZE)
  /* This is defined by running a program from the Makefile. */
  return ((RLIMTYPE) PIPESIZE);
#  else
  errno = EINVAL;
  return RLIM_INVALID;  
#  endif /* PIPESIZE */
#endif /* PIPE_BUF */
}

static RLIMTYPE
getmaxuprc (mode)
     int mode;
{
#  if defined (HAVE_SYSCONF) && defined (_SC_CHILD_MAX)
  return ((RLIMTYPE)sysconf (_SC_CHILD_MAX));
#  else /* !HAVE_SYSCONF || !_SC_CHILD_MAX */
#    if defined (MAXUPRC)
  return ((RLIMTYPE)MAXUPRC);
#    else /* MAXUPRC */
  errno = EINVAL;
  return RLIM_INVALID;
#    endif /* !MAXUPRC */
#  endif /* !HAVE_SYSCONF || !_SC_CHILD_MAX */
}

static void
print_all_limits (mode)
     int mode;
{
  register int i;
  RLIMTYPE value;

  if (mode == 0)
    mode |= LIMIT_SOFT;

  for (i = 0; limits[i].option > 0; i++)
    {
      if (get_limit (i, mode, &value) < 0)
	value = RLIM_INVALID;
      printone (i, value, 1);     
    }
}

static void
printone (limind, curlim, pdesc)
     int limind;
     RLIMTYPE curlim;
     int pdesc;
{
  if (pdesc)
    printf (DESCFMT, limits[limind].description);
  if (curlim == RLIM_INFINITY)
    puts ("unlimited");
  else if (curlim == RLIM_INVALID)
    printf ("cannot get limit: %s\n", strerror (errno));
  else
    print_rlimtype ((curlim / limits[limind].block_factor), 1);
}