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.

1 files changed, 16 insertions, 24 deletions

diff --git a/src/stdio/tmpnam.c b/src/stdio/tmpnam.c
index 2bd72b3b..92f699c2 100644
--- 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;
 }