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make popen/pclose thread safe

This commit is contained in:
cl 2003-09-15 22:30:38 +00:00
parent d889e9a63d
commit 64408794ea
1 changed files with 35 additions and 8 deletions
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43
lib/libc/gen/popen.c
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@ -1,4 +1,4 @@
/* $NetBSD: popen.c,v 1.27 2003/08/07 16:42:55 agc Exp $ */
/* $NetBSD: popen.c,v 1.28 2003/09/15 22:30:38 cl Exp $ */
/*
* Copyright (c) 1988, 1993
@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95";
#else
__RCSID("$NetBSD: popen.c,v 1.27 2003/08/07 16:42:55 agc Exp $");
__RCSID("$NetBSD: popen.c,v 1.28 2003/09/15 22:30:38 cl Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@ -68,9 +68,16 @@ extern rwlock_t __environ_lock;
static struct pid {
struct pid *next;
FILE *fp;
#ifdef _REENTRANT
int fd;
#endif
pid_t pid;
} *pidlist;
#ifdef _REENTRANT
static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
#endif
FILE *
popen(command, type)
const char *command, *type;
@ -108,11 +115,13 @@ popen(command, type)
return (NULL);
}
rwlock_rdlock(&pidlist_lock);
rwlock_rdlock(&__environ_lock);
switch (pid = vfork()) {
case -1: /* Error. */
serrno = errno;
rwlock_unlock(&__environ_lock);
rwlock_unlock(&pidlist_lock);
free(cur);
(void)close(pdes[0]);
(void)close(pdes[1]);
@ -124,7 +133,11 @@ popen(command, type)
from previous popen() calls that remain open in the
parent process are closed in the new child process. */
for (old = pidlist; old; old = old->next)
#ifdef _REENTRANT
close(old->fd); /* don't allow a flush */
#else
close(fileno(old->fp)); /* don't allow a flush */
#endif
if (*type == 'r') {
(void)close(pdes[0]);
@ -151,9 +164,15 @@ popen(command, type)
/* Parent; assume fdopen can't fail. */
if (*type == 'r') {
iop = fdopen(pdes[0], type);
#ifdef _REENTRANT
cur->fd = pdes[0];
#endif
(void)close(pdes[1]);
} else {
iop = fdopen(pdes[1], type);
#ifdef _REENTRANT
cur->fd = pdes[1];
#endif
(void)close(pdes[0]);
}
@ -162,6 +181,7 @@ popen(command, type)
cur->pid = pid;
cur->next = pidlist;
pidlist = cur;
rwlock_unlock(&pidlist_lock);
return (iop);
}
@ -181,25 +201,32 @@ pclose(iop)
_DIAGASSERT(iop != NULL);
rwlock_wrlock(&pidlist_lock);
/* Find the appropriate file pointer. */
for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
if (cur->fp == iop)
break;
if (cur == NULL)
if (cur == NULL) {
rwlock_unlock(&pidlist_lock);
return (-1);
}
(void)fclose(iop);
do {
pid = waitpid(cur->pid, &pstat, 0);
} while (pid == -1 && errno == EINTR);
/* Remove the entry from the linked list. */
if (last == NULL)
pidlist = cur->next;
else
last->next = cur->next;
rwlock_unlock(&pidlist_lock);
do {
pid = waitpid(cur->pid, &pstat, 0);
} while (pid == -1 && errno == EINTR);
free(cur);
return (pid == -1 ? -1 : pstat);
}