Don't call lstat() before readlink() just to see if it's a symlink,

as readlink() will tell you that more cheaply.

ok millert@

1 files changed, 17 insertions, 14 deletions

diff --git a/src/lib/libc/stdlib/realpath.c b/src/lib/libc/stdlib/realpath.c
index 27f1a29061..c691252ccf 100644
--- a/src/lib/libc/stdlib/realpath.c
+++ b/src/lib/libc/stdlib/realpath.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: realpath.c,v 1.20 2015/10/13 20:55:37 millert Exp $ */
+/*      $OpenBSD: realpath.c,v 1.21 2016/08/28 04:08:59 guenther Exp $ */
 /*
  * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
  *
@@ -27,8 +27,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/stat.h>
-
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
@@ -47,7 +45,6 @@
 char *
 realpath(const char *path, char *resolved)
 {
-        struct stat sb;
         char *p, *q, *s;
         size_t left_len, resolved_len;
         unsigned symlinks;
@@ -148,21 +145,27 @@ realpath(const char *path, char *resolved)
                         errno = ENAMETOOLONG;
                         goto err;
                 }
-                if (lstat(resolved, &sb) != 0) {
-                        if (errno == ENOENT && p == NULL) {
-                                errno = serrno;
-                                return (resolved);
+                slen = readlink(resolved, symlink, sizeof(symlink) - 1);
+                if (slen < 0) {
+                        switch (errno) {
+                        case EINVAL:
+                                /* not a symlink, continue to next component */
+                                continue;
+                        case ENOENT:
+                                if (p == NULL) {
+                                        errno = serrno;
+                                        return (resolved);
+                                }
+                                /* FALLTHROUGH */
+                        default:
+                                goto err;
                         }
-                        goto err;
-                }
-                if (S_ISLNK(sb.st_mode)) {
+                } else {
                         if (symlinks++ > SYMLOOP_MAX) {
                                 errno = ELOOP;
                                 goto err;
                         }
-                        slen = readlink(resolved, symlink, sizeof(symlink) - 1);
-                        if (slen < 0)
-                                goto err;
+
                         symlink[slen] = '\0';
                         if (symlink[0] == '/') {
                                 resolved[1] = 0;