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author | jhb <jhb@FreeBSD.org> | 2004-02-04 21:52:57 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2004-02-04 21:52:57 +0000 |
commit | 279b2b827810d149b5b8453900cdea57874ae234 (patch) | |
tree | d9c0a05d62914174d6f00ab22300e935c3e6d983 /sys/fs/procfs | |
parent | f7b1079809c2529c50447de59fdce77a7f5a08f5 (diff) | |
download | FreeBSD-src-279b2b827810d149b5b8453900cdea57874ae234.zip FreeBSD-src-279b2b827810d149b5b8453900cdea57874ae234.tar.gz |
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
Diffstat (limited to 'sys/fs/procfs')
-rw-r--r-- | sys/fs/procfs/procfs_rlimit.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/sys/fs/procfs/procfs_rlimit.c b/sys/fs/procfs/procfs_rlimit.c index 396c079..a9bb64d 100644 --- a/sys/fs/procfs/procfs_rlimit.c +++ b/sys/fs/procfs/procfs_rlimit.c @@ -46,11 +46,15 @@ #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> @@ -59,8 +63,17 @@ 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++) { /* @@ -77,24 +90,25 @@ procfs_doprocrlimit(PFS_FILL_ARGS) * current limit */ - if (p->p_rlimit[i].rlim_cur == RLIM_INFINITY) { + if (limp->pl_rlimit[i].rlim_cur == RLIM_INFINITY) { sbuf_printf(sb, "-1 "); } else { sbuf_printf(sb, "%llu ", - (unsigned long long)p->p_rlimit[i].rlim_cur); + (unsigned long long)limp->pl_rlimit[i].rlim_cur); } /* * maximum limit */ - if (p->p_rlimit[i].rlim_max == RLIM_INFINITY) { + if (limp->pl_rlimit[i].rlim_max == RLIM_INFINITY) { sbuf_printf(sb, "-1\n"); } else { sbuf_printf(sb, "%llu\n", - (unsigned long long)p->p_rlimit[i].rlim_max); + (unsigned long long)limp->pl_rlimit[i].rlim_max); } } + lim_free(limp); return (0); } |