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[Qemu-devel] [PATCH] linux-user: break recursion loop on symlink to . or
From: |
Riku Voipio |
Subject: |
[Qemu-devel] [PATCH] linux-user: break recursion loop on symlink to . or .. |
Date: |
Mon, 19 Jan 2009 17:30:33 +0200 |
User-agent: |
Mutt/1.5.11+cvs20060126 |
From: Mika Westerberg
This patch corrects bug in qemu where it contructs its
internal paths and ends up in recursion loop when filesystem
contains symlink that points to dot '.'.
(Riku: some whitespace fudging to minize diff - the whole
file needs reindenting...)
Signed-off-by: Riku Voipio <address@hidden>
---
linux-user/path.c | 37 ++++++++++++++++++++++++++++++++++++-
1 files changed, 36 insertions(+), 1 deletions(-)
diff --git a/linux-user/path.c b/linux-user/path.c
index 06b1f5f..b991af0 100644
--- a/linux-user/path.c
+++ b/linux-user/path.c
@@ -4,6 +4,7 @@
The assumption is that this area does not change.
*/
#include <sys/types.h>
+#include <assert.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
@@ -52,6 +53,38 @@ static struct pathelem *new_entry(const char *root,
#define streq(a,b) (strcmp((a), (b)) == 0)
+/*
+ * Checks whether directory entry (dent) is valid. This
+ * means that symlinks pointing to '.' and '..' should
+ * be skipped by main recursion code. Returns 1 when
+ * entry is valid.
+ */
+static int
+is_dentry_valid(const char *path, const struct dirent *dent)
+{
+ char fullpath[PATH_MAX];
+ char linkbuf[PATH_MAX];
+ ssize_t len;
+
+ assert(path != NULL);
+ assert(dent != NULL);
+
+ if (dent->d_type != DT_LNK)
+ return (1);
+
+ (void) snprintf(fullpath, sizeof (fullpath), "%s/%s",
+ path, dent->d_name);
+
+ if ((len = readlink(fullpath, linkbuf, sizeof (linkbuf) - 1)) != -1) {
+ linkbuf[len] = '\0';
+ if (streq(linkbuf, ".") || streq(linkbuf, ".."))
+ return (0);
+ }
+
+ return (1);
+}
+
+/* TODO: add recursion count check */
static struct pathelem *add_dir_maybe(struct pathelem *path)
{
DIR *dir;
@@ -61,7 +94,9 @@ static struct pathelem *add_dir_maybe(struct pathelem *path)
while ((dirent = readdir(dir)) != NULL) {
if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
- path = add_entry(path, dirent->d_name);
+ if (is_dentry_valid(path->pathname, dirent)) {
+ path = add_entry(path, dirent->d_name);
+ }
}
}
closedir(dir);
--
1.5.6.5
--
"rm -rf" only sounds scary if you don't have backups
- [Qemu-devel] [PATCH] linux-user: break recursion loop on symlink to . or ..,
Riku Voipio <=