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

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

View File

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

View File

@ -26,5 +26,5 @@ char *tmpnam(char *s)
n = ts.tv_nsec ^ (unsigned)&s ^ (unsigned)s; n = ts.tv_nsec ^ (unsigned)&s ^ (unsigned)s;
snprintf(s, L_tmpnam, "/tmp/t%x-%x", a_fetch_add(&index, 1), n); snprintf(s, L_tmpnam, "/tmp/t%x-%x", a_fetch_add(&index, 1), n);
} while (!__syscall(SYS_access, s, F_OK) && try++<MAXTRIES); } while (!__syscall(SYS_access, s, F_OK) && try++<MAXTRIES);
return try==MAXTRIES ? 0 : s; return try>=MAXTRIES ? 0 : s;
} }