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fix tempnam name generation, and a small bug in tmpnam on retry limit

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This commit is contained in:
Rich Felker 2011-03-29 09:00:22 -04:00
parent a88edbec15
commit 8250742b90
2 changed files with 20 additions and 21 deletions
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39
src/stdio/tempnam.c
View File

@ -1,19 +1,22 @@
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.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 +24,18 @@ 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 ^ (unsigned)&s ^ (unsigned)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;
}

2
src/stdio/tmpnam.c
View File

@ -26,5 +26,5 @@ char *tmpnam(char *s)
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;
return try>=MAXTRIES ? 0 : s;
}