fix (deprecated) mktemp logic and update it to match other temp functions

the access function cannot be used to check for existence, because it
operates using real uid/gid rather than effective to determine
accessibility; this matters for the non-final path components.
instead, use stat. failure of stat is success if only the final
component is missing (ENOENT) and otherwise is failure.

diff --git a/src/temp/mktemp.c b/src/temp/mktemp.c
index a1c89a6..67130e1 100644 (file)
--- a/src/temp/mktemp.c
+++ b/src/temp/mktemp.c
@@ -2,23 +2,30 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
+#include <sys/stat.h>
 
 char *__randname(char *);
 
 char *mktemp(char *template)
 {
        size_t l = strlen(template);
-       int retries = 10000;
+       int retries = 100;
+       struct stat st;
 
        if (l < 6 || memcmp(template+l-6, "XXXXXX", 6)) {
                errno = EINVAL;
                *template = 0;
                return template;
        }
-       while (retries--) {
+
+       do {
                __randname(template+l-6);
-               if (access(template, F_OK) < 0) return template;
-       }
+               if (stat(template, &st)) {
+                       if (errno != ENOENT) *template = 0;
+                       return template;
+               }
+       } while (--retries);
+
        *template = 0;
        errno = EEXIST;
        return template;