[src/netbsd-8]: src/lib/libc/gen Pull up following revision(s) (requested by ...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b94f3fc9b92e
branches:  netbsd-8
changeset: 447903:b94f3fc9b92e
user:      martin <martin%NetBSD.org@localhost>
date:      Sun Jan 27 18:25:52 2019 +0000

description:
Pull up following revision(s) (requested by christos in ticket #1170):

        lib/libc/gen/popen.c: revision 1.36

PR/53904: Jintao Zhu: Use a mutex instead of an rwlock to assure thread safety

diffstat:

 lib/libc/gen/popen.c |  55 +++++++++++++++++++++++----------------------------
 1 files changed, 25 insertions(+), 30 deletions(-)

diffs (132 lines):

diff -r cb2fc3a1d775 -r b94f3fc9b92e lib/libc/gen/popen.c
--- a/lib/libc/gen/popen.c      Thu Jan 24 15:36:05 2019 +0000
+++ b/lib/libc/gen/popen.c      Sun Jan 27 18:25:52 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: popen.c,v 1.35 2015/02/02 22:07:05 christos Exp $      */
+/*     $NetBSD: popen.c,v 1.35.8.1 2019/01/27 18:25:52 martin 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 1.35 2015/02/02 22:07:05 christos Exp $");
+__RCSID("$NetBSD: popen.c,v 1.35.8.1 2019/01/27 18:25:52 martin Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -73,7 +73,20 @@
 } *pidlist; 
        
 #ifdef _REENTRANT
-static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
+static  mutex_t pidlist_mutex = MUTEX_INITIALIZER;
+# define MUTEX_LOCK() \
+    do { \
+           if (__isthreaded) \
+                   mutex_lock(&pidlist_mutex); \
+    } while (/*CONSTCOND*/0)
+# define MUTEX_UNLOCK() \
+    do { \
+           if (__isthreaded) \
+                   mutex_unlock(&pidlist_mutex); \
+    } while (/*CONSTCOND*/0)
+#else
+# define MUTEX_LOCK() __nothing
+# define MUTEX_UNLOCK() __nothing
 #endif
 
 static struct pid *
@@ -183,17 +196,13 @@
        if ((cur = pdes_get(pdes, &type)) == NULL)
                return NULL;
 
-#ifdef _REENTRANT
-       (void)rwlock_rdlock(&pidlist_lock);
-#endif
+       MUTEX_LOCK();
        (void)__readlockenv();
        switch (pid = vfork()) {
        case -1:                        /* Error. */
                serrno = errno;
                (void)__unlockenv();
-#ifdef _REENTRANT
-               (void)rwlock_unlock(&pidlist_lock);
-#endif
+               MUTEX_UNLOCK();
                pdes_error(pdes, cur);
                errno = serrno;
                return NULL;
@@ -208,9 +217,7 @@
 
        pdes_parent(pdes, cur, pid, type);
 
-#ifdef _REENTRANT
-       (void)rwlock_unlock(&pidlist_lock);
-#endif
+       MUTEX_UNLOCK();
 
        return cur->fp;
 }
@@ -228,15 +235,11 @@
        if ((cur = pdes_get(pdes, &type)) == NULL)
                return NULL;
 
-#ifdef _REENTRANT
-       (void)rwlock_rdlock(&pidlist_lock);
-#endif
+       MUTEX_LOCK();
        switch (pid = vfork()) {
        case -1:                        /* Error. */
                serrno = errno;
-#ifdef _REENTRANT
-               (void)rwlock_unlock(&pidlist_lock);
-#endif
+               MUTEX_UNLOCK();
                pdes_error(pdes, cur);
                errno = serrno;
                return NULL;
@@ -250,9 +253,7 @@
 
        pdes_parent(pdes, cur, pid, type);
 
-#ifdef _REENTRANT
-       (void)rwlock_unlock(&pidlist_lock);
-#endif
+       MUTEX_UNLOCK();
 
        return cur->fp;
 }
@@ -271,18 +272,14 @@
 
        _DIAGASSERT(iop != NULL);
 
-#ifdef _REENTRANT
-       rwlock_wrlock(&pidlist_lock);
-#endif
+       MUTEX_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) {
-#ifdef _REENTRANT
-               (void)rwlock_unlock(&pidlist_lock);
-#endif
+               MUTEX_UNLOCK();
                errno = ESRCH;
                return -1;
        }
@@ -295,9 +292,7 @@
        else
                last->next = cur->next;
 
-#ifdef _REENTRANT
-       (void)rwlock_unlock(&pidlist_lock);
-#endif
+       MUTEX_UNLOCK();
 
        do {
                pid = waitpid(cur->pid, &pstat, 0);