fix usage of locks with vfork

[musl] / src / stdio / tempnam.c

diff --git a/src/stdio/tempnam.c b/src/stdio/tempnam.c
index 2cbcb86..f73ca9f 100644 (file)
--- a/src/stdio/tempnam.c
+++ b/src/stdio/tempnam.c
@@ -1,19 +1,23 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <fcntl.h>
+#include <stdint.h>
 #include <unistd.h>
-#include <limits.h>
-#include <errno.h>
+#include <time.h>
 #include "libc.h"
+#include "atomic.h"
+
+#define MAXTRIES 100
 
 char *tempnam(const char *dir, const char *pfx)
 {
-       static int lock;
        static int index;
        char *s;
+       struct timespec ts;
        int pid = getpid();
-       int l;
+       size_t l;
+       int n;
+       int try=0;
 
        if (!dir) dir = P_tmpdir;
        if (!pfx) pfx = "temp";
@@ -21,22 +25,18 @@ char *tempnam(const char *dir, const char *pfx)
        if (access(dir, R_OK|W_OK|X_OK) != 0)
                return NULL;
 
-       l = strlen(dir) + 1 + strlen(pfx) + 2 + sizeof(int)*3*2 + 1;
+       l = strlen(dir) + 1 + strlen(pfx) + 3*(sizeof(int)*3+2) + 1;
        s = malloc(l);
-       if (!s) {
-               errno = ENOMEM;
-               return NULL;
-       }
+       if (!s) return s;
 
-       LOCK(&lock);
-       for (; index < TMP_MAX; index++) {
-               snprintf(s, l, "%s/%s-%d-%d", dir, pfx, pid, index);
-               if (access(s, F_OK) != 0) {
-                       UNLOCK(&lock);
-                       return s;
-               }
+       do {
+               clock_gettime(CLOCK_REALTIME, &ts);
+               n = ts.tv_nsec ^ (uintptr_t)&s ^ (uintptr_t)s;
+               snprintf(s, l, "%s/%s-%d-%d-%x", dir, pfx, pid, a_fetch_add(&index, 1), n);
+       } while (!access(s, F_OK) && try++<MAXTRIES);
+       if (try>=MAXTRIES) {
+               free(s);
+               return 0;
        }
-       UNLOCK(&lock);
-       free(s);
-       return NULL;    
+       return s;
 }