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Convert popen()'s `pidlist' to a SLIST, for consistency.

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I guess the original author of the popen() code didn't want to use our
<sys/queue.h> macro's, because the single linked list macro's didn't
offer O(1) deletion. Because I introduced SLIST_REMOVE_NEXT() some time
ago, we can now use the macro's here.

By converting the code to an SLIST, it is more consistent with other
parts of the C library and the operating system.

Reviewed by:	csjp
Approved by:	philip (mentor, implicit)
This commit is contained in:
Ed Schouten 2008-07-29 16:29:59 +00:00
parent b423c28f74
commit 7e7f7ca3c6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=180963
1 changed files with 13 additions and 11 deletions
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24
lib/libc/gen/popen.c
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@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/wait.h>
#include <signal.h>
@ -53,11 +54,12 @@ __FBSDID("$FreeBSD$");
extern char **environ;
static struct pid {
struct pid *next;
struct pid {
SLIST_ENTRY(pid) next;
FILE *fp;
pid_t pid;
} *pidlist;
};
static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
#define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
@ -133,9 +135,8 @@ popen(command, type)
}
(void)_close(pdes[1]);
}
for (p = pidlist; p; p = p->next) {
SLIST_FOREACH(p, &pidlist, next)
(void)_close(fileno(p->fp));
}
_execve(_PATH_BSHELL, argv, environ);
_exit(127);
/* NOTREACHED */
@ -155,8 +156,7 @@ popen(command, type)
cur->fp = iop;
cur->pid = pid;
THREAD_LOCK();
cur->next = pidlist;
pidlist = cur;
SLIST_INSERT_HEAD(&pidlist, cur, next);
THREAD_UNLOCK();
return (iop);
@ -171,7 +171,7 @@ int
pclose(iop)
FILE *iop;
{
struct pid *cur, *last;
struct pid *cur, *last = NULL;
int pstat;
pid_t pid;
@ -179,17 +179,19 @@ pclose(iop)
* Find the appropriate file pointer and remove it from the list.
*/
THREAD_LOCK();
for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
SLIST_FOREACH(cur, &pidlist, next) {
if (cur->fp == iop)
break;
last = cur;
}
if (cur == NULL) {
THREAD_UNLOCK();
return (-1);
}
if (last == NULL)
pidlist = cur->next;
SLIST_REMOVE_HEAD(&pidlist, next);
else
last->next = cur->next;
SLIST_REMOVE_NEXT(&pidlist, last, next);
THREAD_UNLOCK();
(void)fclose(iop);