I've rewritten virFileLinkPointsTo to be a lot simpler,
and more importantly, it has far fewer failure points.
If anyone wants to preserve the original behavior that
makes it fail when the first parameter does not specify
a symlink, I can add that. The only difference in behavior
would be when the two files are hard-linked.
In any case, I'll remove the FIXME comment.
The diff below is not very readable. Bottom line,
it replaces a pair of functions (the latter is a stub for mingw)
with this:
#define SAME_INODE(Stat_buf_1, Stat_buf_2) \
((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
&& (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
int virFileLinkPointsTo(const char *checkLink,
const char *checkDest)
{
struct stat src_sb;
struct stat dest_sb;
if (stat (checkLink, &src_sb) || stat (checkDest, &dest_sb))
return 0;
/* FIXME: if required, lstat checkLink to ensure it's a symlink */
if (! SAME_INODE (src_sb, dest_sb)) {
virLog("Link '%s' does not point to '%s', ignoring\n",
checkLink, checkDest);
return 0;
}
return 1;
}
>From 4e70c02e547b078b8f35afd0996b6887e1593afd Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@xxxxxxxxxx>
Date: Tue, 12 Aug 2008 19:07:46 +0200
Subject: [PATCH] rewrite virFileLinkPointsTo
* src/util.c (SAME_INODE): Define.
(virFileLinkPointsTo): Rewrite to be more portable and more efficient.
---
src/util.c | 97 ++++++-----------------------------------------------------
1 files changed, 10 insertions(+), 87 deletions(-)
diff --git a/src/util.c b/src/util.c
index 9f056e0..2905a0a 100644
--- a/src/util.c
+++ b/src/util.c
@@ -397,107 +397,30 @@ int virFileHasSuffix(const char *str,
return STREQ(str + len - suffixlen, suffix);
}
-#ifndef __MINGW32__
+#define SAME_INODE(Stat_buf_1, Stat_buf_2) \
+ ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
+ && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
int virFileLinkPointsTo(const char *checkLink,
const char *checkDest)
{
- char dest[PATH_MAX];
- char real[PATH_MAX];
- char checkReal[PATH_MAX];
- int n;
-
- /* read the link destination */
- if ((n = readlink(checkLink, dest, PATH_MAX)) < 0) {
- switch (errno) {
- case ENOENT:
- case ENOTDIR:
- return 0;
-
- case EINVAL:
- virLog("File '%s' is not a symlink\n",
- checkLink);
- return 0;
-
- }
- virLog("Failed to read symlink '%s': %s\n",
- checkLink, strerror(errno));
- return 0;
- } else if (n >= PATH_MAX) {
- virLog("Symlink '%s' contents too long to fit in buffer\n",
- checkLink);
- return 0;
- }
+ struct stat src_sb;
+ struct stat dest_sb;
- dest[n] = '\0';
+ if (stat (checkLink, &src_sb) || stat (checkDest, &dest_sb))
+ return 0;
- /* make absolute */
- if (dest[0] != '/') {
- char dir[PATH_MAX];
- char tmp[PATH_MAX];
- char *p;
+ /* FIXME: if required, lstat checkLink to ensure it's a symlink */
- strncpy(dir, checkLink, PATH_MAX);
- dir[PATH_MAX-1] = '\0';
-
- if (!(p = strrchr(dir, '/'))) {
- virLog("Symlink path '%s' is not absolute\n", checkLink);
- return 0;
- }
-
- if (p == dir) /* handle unlikely root dir case */
- p++;
-
- *p = '\0';
-
- if (virFileBuildPath(dir, dest, NULL, tmp, PATH_MAX) < 0) {
- virLog("Path '%s/%s' is too long\n", dir, dest);
- return 0;
- }
-
- strncpy(dest, tmp, PATH_MAX);
- dest[PATH_MAX-1] = '\0';
- }
-
- /* canonicalize both paths */
- if (!realpath(dest, real)) {
- virLog("Failed to expand path '%s' :%s\n", dest, strerror(errno));
- strncpy(real, dest, PATH_MAX);
- real[PATH_MAX-1] = '\0';
- }
-
- if (!realpath(checkDest, checkReal)) {
- virLog("Failed to expand path '%s' :%s\n", checkDest, strerror(errno));
- strncpy(checkReal, checkDest, PATH_MAX);
- checkReal[PATH_MAX-1] = '\0';
- }
-
- /* compare */
- if (STRNEQ(checkReal, real)) {
+ if (! SAME_INODE (src_sb, dest_sb)) {
virLog("Link '%s' does not point to '%s', ignoring\n",
- checkLink, checkReal);
+ checkLink, checkDest);
return 0;
}
return 1;
}
-#else /* !__MINGW32__ */
-
-/* Gnulib has an implementation of readlink which could be used
- * to implement this, but it requires LGPLv3.
- */
-
-int
-virFileLinkPointsTo (const char *checkLink ATTRIBUTE_UNUSED,
- const char *checkDest ATTRIBUTE_UNUSED)
-{
- virLog (_("%s: not implemented\n"), __FUNCTION__);
- return 0;
-}
-
-#endif /*! __MINGW32__ */
-
int virFileExists(const char *path)
{
struct stat st;
--
1.6.0.rc2.38.g413e06
--
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