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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/kern/kern_descrip.c | |
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/kern/kern_descrip.c')
-rw-r--r-- | sys/kern/kern_descrip.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index b6eaee2..abaac90 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -224,10 +224,10 @@ getdtablesize(td, uap) { struct proc *p = td->td_proc; - mtx_lock(&Giant); + PROC_LOCK(p); td->td_retval[0] = - min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); - mtx_unlock(&Giant); + min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); + PROC_UNLOCK(p); return (0); } @@ -353,11 +353,14 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) case F_DUPFD: FILEDESC_UNLOCK(fdp); newmin = arg; - if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur || + PROC_LOCK(p); + if (newmin >= lim_cur(p, RLIMIT_NOFILE) || newmin >= maxfilesperproc) { + PROC_UNLOCK(p); error = EINVAL; break; } + PROC_UNLOCK(p); error = do_dup(td, DUP_VARIABLE, fd, newmin, td->td_retval); break; @@ -572,7 +575,9 @@ do_dup(td, type, old, new, retval) */ if (old < 0 || new < 0) return (EBADF); - maxfd = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); + PROC_LOCK(p); + maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); + PROC_UNLOCK(p); if (new >= maxfd) return (EMFILE); @@ -1213,7 +1218,9 @@ fdalloc(struct thread *td, int minfd, int *result) FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); - maxfd = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); + PROC_LOCK(p); + maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); + PROC_UNLOCK(p); /* * Search the bitmap for a free descriptor. If none is found, try @@ -1261,7 +1268,9 @@ fdavail(td, n) FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); - lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc); + PROC_LOCK(p); + lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc); + PROC_UNLOCK(p); if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0) return (1); last = min(fdp->fd_nfiles, lim); |