Libc-1439.100.3.tar.gz

[apple/libc.git] / util / opendev.c

diff --git a/util/opendev.c b/util/opendev.c
index e16c707705f93bdd51ab8e9de137d1299198684a..ee5c85bce1275125b99c36ee60fa8c5375972c68 100644 (file)
--- a/util/opendev.c
+++ b/util/opendev.c
@@ -31,9 +31,22 @@
 #include <paths.h>
 #include <stdio.h>
 #include <string.h>
+#include <pthread.h>
 
 #include "util.h"
 
+/*
+ * opendev(3) is an inherently non-thread-safe API, since
+ * it returns a buffer to global storage. However we can
+ * at least make sure the storage allocation is thread safe
+ * and does not leak memory in case of simultaneous
+ * initialization
+ */
+static pthread_once_t opendev_namebuf_once = PTHREAD_ONCE_INIT;
+static char *namebuf = NULL;
+
+static void opendev_namebuf_init(void);
+
 int
 opendev(path, oflags, dflags, realpath)
        char *path;
@@ -43,7 +56,6 @@ opendev(path, oflags, dflags, realpath)
 {
        int fd;
        char *slash, *prefix;
-       static char namebuf[PATH_MAX];
 
        /* Initial state */
        if (realpath)
@@ -51,6 +63,13 @@ opendev(path, oflags, dflags, realpath)
        fd = -1;
        errno = ENOENT;
 
+       if (pthread_once(&opendev_namebuf_once,
+                                        opendev_namebuf_init)
+               || !namebuf) {
+               errno = ENOMEM;
+               return -1;
+       }
+
        if (dflags & OPENDEV_BLCK)
                prefix = "";                    /* block device */
        else
@@ -59,8 +78,8 @@ opendev(path, oflags, dflags, realpath)
        if ((slash = strchr(path, '/')))
                fd = open(path, oflags);
        else if (dflags & OPENDEV_PART) {
-               if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
-                   _PATH_DEV, prefix, path) < sizeof(namebuf)) {
+               if (snprintf(namebuf, PATH_MAX, "%s%s%s",
+                   _PATH_DEV, prefix, path) < PATH_MAX) {
                        char *slice;
                        while ((slice = strrchr(namebuf, 's')) &&
                            isdigit(*(slice-1))) *slice = '\0';
@@ -71,8 +90,8 @@ opendev(path, oflags, dflags, realpath)
                        errno = ENAMETOOLONG;
        }
        if (!slash && fd == -1 && errno == ENOENT) {
-               if (snprintf(namebuf, sizeof(namebuf), "%s%s%s",
-                   _PATH_DEV, prefix, path) < sizeof(namebuf)) {
+               if (snprintf(namebuf, PATH_MAX, "%s%s%s",
+                   _PATH_DEV, prefix, path) < PATH_MAX) {
                        fd = open(namebuf, oflags);
                        if (realpath)
                                *realpath = namebuf;
@@ -81,3 +100,8 @@ opendev(path, oflags, dflags, realpath)
        }
        return (fd);
 }
+
+static void opendev_namebuf_init(void)
+{
+       namebuf = malloc(PATH_MAX);
+}