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authorRich Felker <dalias@aerifal.cx>2011-03-29 08:34:47 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-29 08:34:47 -0400
commit507a9fa6ff9948eb7d858467b7be2cb1dcf15d03 (patch)
tree90d5e4f8977942072e5a418dbc7ea5bbc8cd72be /src/stdio
parent9646e4d024c05332c9653419abd6c41fdd48a33b (diff)
downloadmusl-507a9fa6ff9948eb7d858467b7be2cb1dcf15d03.tar.gz
fix tmpnam to generate better names, not depend on non-ISO-C symbols
Diffstat (limited to 'src/stdio')
-rw-r--r--src/stdio/tmpnam.c42
1 files changed, 17 insertions, 25 deletions
diff --git a/src/stdio/tmpnam.c b/src/stdio/tmpnam.c
index 14d59220..6099b74b 100644
--- a/src/stdio/tmpnam.c
+++ b/src/stdio/tmpnam.c
@@ -1,38 +1,30 @@
#include <stdio.h>
#include <stdlib.h>
-#include <string.h>
-#include <limits.h>
#include <unistd.h>
+#include <time.h>
#include "libc.h"
+#include "syscall.h"
+#include "atomic.h"
+
+#define MAXTRIES 100
char *tmpnam(char *s)
{
- static int lock;
static int index;
- static char *s2;
- int pid = getpid();
- char *dir = getenv("TMPDIR");
-
- if (!s) {
- if (!s2) s2 = malloc(L_tmpnam);
- s = s2;
- }
+ static char s2[L_tmpnam];
+ struct timespec ts;
+ int try = 0;
+ unsigned n;
- /* this interface is insecure anyway but at least we can try.. */
- if (!dir || strlen(dir) > L_tmpnam-32)
- dir = P_tmpdir;
+ if (!s) s = s2;
- if (access(dir, R_OK|W_OK|X_OK) != 0)
+ if (__syscall(SYS_access, P_tmpdir, R_OK|W_OK|X_OK) != 0)
return NULL;
- LOCK(&lock);
- for (index++; index < TMP_MAX; index++) {
- snprintf(s, L_tmpnam, "%s/temp%d-%d", dir, pid, index);
- if (access(s, F_OK) != 0) {
- UNLOCK(&lock);
- return s;
- }
- }
- UNLOCK(&lock);
- return NULL;
+ do {
+ __syscall(SYS_clock_gettime, CLOCK_REALTIME, &ts, 0);
+ n = ts.tv_nsec ^ (unsigned)&s ^ (unsigned)s;
+ snprintf(s, L_tmpnam, "/tmp/t%x-%x", a_fetch_add(&index, 1), n);
+ } while (!__syscall(SYS_access, s, F_OK) && try++<MAXTRIES);
+ return try==MAXTRIES ? 0 : s;
}