freebsd-skq/sys/fs/procfs/procfs_rlimit.c
John Baldwin 91d5354a2c Locking for the per-process resource limits structure.
- struct plimit includes a mutex to protect a reference count.  The plimit
  structure is treated similarly to struct ucred in that is is always copy
  on write, so having a reference to a structure is sufficient to read from
  it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
  limits from a process to keep the limit structure from changing out from
  under you while reading from it.
- Various global limits that are ints are not protected by a lock since
  int writes are atomic on all the archs we support and thus a lock
  wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
  behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
  either an rlimit, or the current or max individual limit of the specified
  resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
  other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
  (it didn't used the stackgap when it should have) but uses lim_rlimit()
  and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
  but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits.  It
  also no longer uses the stackgap for accessing sysctl's for the
  ibcs2_sysconf() syscall but uses kernel_sysctl() instead.  As a result,
  ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.

Submitted by:	mtm (mostly, I only did a few cleanups and catchups)
Tested on:	i386
Compiled on:	alpha, amd64
2004-02-04 21:52:57 +00:00

115 lines
3.2 KiB
C

/*
* Copyright (c) 1999 Adrian Chadd
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)procfs_status.c 8.4 (Berkeley) 6/15/94
*
* $FreeBSD$
*/
/*
* To get resource.h to include our rlimit_ident[] array of rlimit identifiers
*/
#define _RLIMIT_IDENT
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/resource.h>
#include <sys/sbuf.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <fs/pseudofs/pseudofs.h>
#include <fs/procfs/procfs.h>
int
procfs_doprocrlimit(PFS_FILL_ARGS)
{
struct plimit *limp;
int i;
/*
* Obtain a private reference to resource limits
*/
PROC_LOCK(p);
limp = lim_hold(p->p_limit);
PROC_UNLOCK(p);
for (i = 0; i < RLIM_NLIMITS; i++) {
/*
* Add the rlimit ident
*/
sbuf_printf(sb, "%s ", rlimit_ident[i]);
/*
* Replace RLIM_INFINITY with -1 in the string
*/
/*
* current limit
*/
if (limp->pl_rlimit[i].rlim_cur == RLIM_INFINITY) {
sbuf_printf(sb, "-1 ");
} else {
sbuf_printf(sb, "%llu ",
(unsigned long long)limp->pl_rlimit[i].rlim_cur);
}
/*
* maximum limit
*/
if (limp->pl_rlimit[i].rlim_max == RLIM_INFINITY) {
sbuf_printf(sb, "-1\n");
} else {
sbuf_printf(sb, "%llu\n",
(unsigned long long)limp->pl_rlimit[i].rlim_max);
}
}
lim_free(limp);
return (0);
}