overhaul tmpfile, tmpnam, and tempnam functions

these all now use the shared __randname function internally, rather
than duplicating logic for producing a random name. incorrect usage of
the access syscall (which works with real uid/gid, not effective) has
been removed, along with unnecessary heavy dependencies like snprintf.

diff --git a/src/stdio/tempnam.c b/src/stdio/tempnam.c
index f73ca9f..9bf8c72 100644 (file)
--- a/src/stdio/tempnam.c
+++ b/src/stdio/tempnam.c
@@ -1,42 +1,43 @@
 #include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <limits.h>
 #include <string.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <time.h>
-#include "libc.h"
-#include "atomic.h"
+#include "syscall.h"
 
 #define MAXTRIES 100
 
+char *__randname(char *);
+
 char *tempnam(const char *dir, const char *pfx)
 {
-       static int index;
-       char *s;
-       struct timespec ts;
-       int pid = getpid();
-       size_t l;
-       int n;
-       int try=0;
+       char s[PATH_MAX];
+       size_t l, dl, pl;
+       int try;
+       int r;
 
        if (!dir) dir = P_tmpdir;
        if (!pfx) pfx = "temp";
 
-       if (access(dir, R_OK|W_OK|X_OK) != 0)
-               return NULL;
-
-       l = strlen(dir) + 1 + strlen(pfx) + 3*(sizeof(int)*3+2) + 1;
-       s = malloc(l);
-       if (!s) return s;
+       dl = strlen(dir);
+       pl = strlen(pfx);
+       l = dl + 1 + pl + 1 + 6;
 
-       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);
+       if (l >= PATH_MAX) {
+               errno = ENAMETOOLONG;
                return 0;
        }
-       return s;
+
+       memcpy(s, dir, dl);
+       s[dl] = '/';
+       memcpy(s+dl+1, pfx, pl);
+       s[dl+1+pl] = '_';
+
+       for (try=0; try<MAXTRIES; try++) {
+               __randname(s+l-6);
+               r = __syscall(SYS_lstat, s, &(struct stat){0});
+               if (r == -ENOENT) return strdup(s);
+       }
+       return 0;
 }

diff --git a/src/stdio/tmpfile.c b/src/stdio/tmpfile.c
index b0d0ba0..c856994 100644 (file)
--- a/src/stdio/tmpfile.c
+++ b/src/stdio/tmpfile.c
@@ -1,19 +1,19 @@
 #include <stdio.h>
 #include <fcntl.h>
-#include <unistd.h>
 #include "stdio_impl.h"
 
 #define MAXTRIES 100
 
+char *__randname(char *);
+
 FILE *tmpfile(void)
 {
-       char buf[L_tmpnam], *s;
+       char s[] = "/tmp/tmpfile_XXXXXX";
        int fd;
        FILE *f;
        int try;
        for (try=0; try<MAXTRIES; try++) {
-               s = tmpnam(buf);
-               if (!s) return 0;
+               __randname(s+13);
                fd = sys_open(s, O_RDWR|O_CREAT|O_EXCL, 0600);
                if (fd >= 0) {
                        f = __fdopen(fd, "w+");

diff --git a/src/stdio/tmpnam.c b/src/stdio/tmpnam.c
index 2bd72b3..92f699c 100644 (file)
--- a/src/stdio/tmpnam.c
+++ b/src/stdio/tmpnam.c
@@ -1,31 +1,23 @@
 #include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <time.h>
-#include "libc.h"
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
 #include "syscall.h"
-#include "atomic.h"
 
 #define MAXTRIES 100
 
-char *tmpnam(char *s)
-{
-       static int index;
-       static char s2[L_tmpnam];
-       struct timespec ts;
-       int try = 0;
-       unsigned n;
-
-       if (!s) s = s2;
+char *__randname(char *);
 
-       if (__syscall(SYS_access, P_tmpdir, R_OK|W_OK|X_OK) != 0)
-               return NULL;
-
-       do {
-               __syscall(SYS_clock_gettime, CLOCK_REALTIME, &ts, 0);
-               n = ts.tv_nsec ^ (uintptr_t)&s ^ (uintptr_t)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;
+char *tmpnam(char *buf)
+{
+       static char internal[L_tmpnam];
+       char s[] = "/tmp/tmpnam_XXXXXX";
+       int try;
+       int r;
+       for (try=0; try<MAXTRIES; try++) {
+               __randname(s+12);
+               r = __syscall(SYS_lstat, s, &(struct stat){0});
+               if (r == -ENOENT) return strcpy(buf ? buf : internal, s);
+       }
+       return 0;
 }