upstream commit

revision 1.14
date: 2011/07/24 21:03:00;  author: miod;  state: Exp;  lines: +35 -13;
Recent Single Unix will malloc memory if the second argument of realpath()
is NULL, and third-party software is starting to rely upon this.
Adapted from FreeBSD via Jona Joachim (jaj ; hcl-club , .lu), with minor
tweaks from nicm@ and yours truly.

diff --git a/openbsd-compat/realpath.c b/openbsd-compat/realpath.c
index ba4cea93894fa4e8ec973002dc54adc476804066..6646330cab97fb6bae62898c6ff68092e0335103 100644 (file)
--- a/openbsd-compat/realpath.c
+++ b/openbsd-compat/realpath.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $ */
+/*     $OpenBSD: realpath.c,v 1.14 2011/07/24 21:03:00 miod Exp $ */
 /*
  * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
  *
@@ -51,16 +51,30 @@
  * in which case the path which caused trouble is left in (resolved).
  */
 char *
-realpath(const char *path, char resolved[PATH_MAX])
+realpath(const char *path, char *resolved)
 {
        struct stat sb;
        char *p, *q, *s;
        size_t left_len, resolved_len;
        unsigned symlinks;
-       int serrno, slen;
+       int serrno, slen, mem_allocated;
        char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
 
+       if (path[0] == '\0') {
+               errno = ENOENT;
+               return (NULL);
+       }
+
        serrno = errno;
+
+       if (resolved == NULL) {
+               resolved = malloc(PATH_MAX);
+               if (resolved == NULL)
+                       return (NULL);
+               mem_allocated = 1;
+       } else
+               mem_allocated = 0;
+
        symlinks = 0;
        if (path[0] == '/') {
                resolved[0] = '/';
@@ -71,7 +85,10 @@ realpath(const char *path, char resolved[PATH_MAX])
                left_len = strlcpy(left, path + 1, sizeof(left));
        } else {
                if (getcwd(resolved, PATH_MAX) == NULL) {
-                       strlcpy(resolved, ".", PATH_MAX);
+                       if (mem_allocated)
+                               free(resolved);
+                       else
+                               strlcpy(resolved, ".", PATH_MAX);
                        return (NULL);
                }
                resolved_len = strlen(resolved);
@@ -79,7 +96,7 @@ realpath(const char *path, char resolved[PATH_MAX])
        }
        if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
                errno = ENAMETOOLONG;
-               return (NULL);
+               goto err;
        }
 
        /*
@@ -94,7 +111,7 @@ realpath(const char *path, char resolved[PATH_MAX])
                s = p ? p : left + left_len;
                if (s - left >= (ptrdiff_t)sizeof(next_token)) {
                        errno = ENAMETOOLONG;
-                       return (NULL);
+                       goto err;
                }
                memcpy(next_token, left, s - left);
                next_token[s - left] = '\0';
@@ -104,7 +121,7 @@ realpath(const char *path, char resolved[PATH_MAX])
                if (resolved[resolved_len - 1] != '/') {
                        if (resolved_len + 1 >= PATH_MAX) {
                                errno = ENAMETOOLONG;
-                               return (NULL);
+                               goto err;
                        }
                        resolved[resolved_len++] = '/';
                        resolved[resolved_len] = '\0';
@@ -135,23 +152,23 @@ realpath(const char *path, char resolved[PATH_MAX])
                resolved_len = strlcat(resolved, next_token, PATH_MAX);
                if (resolved_len >= PATH_MAX) {
                        errno = ENAMETOOLONG;
-                       return (NULL);
+                       goto err;
                }
                if (lstat(resolved, &sb) != 0) {
                        if (errno == ENOENT && p == NULL) {
                                errno = serrno;
                                return (resolved);
                        }
-                       return (NULL);
+                       goto err;
                }
                if (S_ISLNK(sb.st_mode)) {
                        if (symlinks++ > MAXSYMLINKS) {
                                errno = ELOOP;
-                               return (NULL);
+                               goto err;
                        }
                        slen = readlink(resolved, symlink, sizeof(symlink) - 1);
                        if (slen < 0)
-                               return (NULL);
+                               goto err;
                        symlink[slen] = '\0';
                        if (symlink[0] == '/') {
                                resolved[1] = 0;
@@ -174,7 +191,7 @@ realpath(const char *path, char resolved[PATH_MAX])
                                        if (slen + 1 >=
                                            (ptrdiff_t)sizeof(symlink)) {
                                                errno = ENAMETOOLONG;
-                                               return (NULL);
+                                               goto err;
                                        }
                                        symlink[slen] = '/';
                                        symlink[slen + 1] = 0;
@@ -182,7 +199,7 @@ realpath(const char *path, char resolved[PATH_MAX])
                                left_len = strlcat(symlink, left, sizeof(left));
                                if (left_len >= sizeof(left)) {
                                        errno = ENAMETOOLONG;
-                                       return (NULL);
+                                       goto err;
                                }
                        }
                        left_len = strlcpy(left, symlink, sizeof(left));
@@ -196,5 +213,10 @@ realpath(const char *path, char resolved[PATH_MAX])
        if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
                resolved[resolved_len - 1] = '\0';
        return (resolved);
+
+err:
+       if (mem_allocated)
+               free(resolved);
+       return (NULL);
 }
 #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */