From 2fe6579125fe042f2255afbf00fc8e4b80d6a6be Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Tue, 27 May 2014 00:44:23 -0400
Subject: 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.
---
 src/stdio/tempnam.c | 55 +++++++++++++++++++++++++++--------------------------
 1 file changed, 28 insertions(+), 27 deletions(-)

(limited to 'src/stdio/tempnam.c')

diff --git a/src/stdio/tempnam.c b/src/stdio/tempnam.c
index f73ca9f9..9bf8c727 100644
--- 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;
 }
-- 
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