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-rw-r--r--abspath.c105
1 files changed, 84 insertions, 21 deletions
diff --git a/abspath.c b/abspath.c
index 05f2d79348..40cdc46219 100644
--- a/abspath.c
+++ b/abspath.c
@@ -15,16 +15,34 @@ int is_directory(const char *path)
#define MAXDEPTH 5
/*
- * Use this to get the real path, i.e. resolve links. If you want an
- * absolute path but don't mind links, use absolute_path.
+ * Return the real path (i.e., absolute path, with symlinks resolved
+ * and extra slashes removed) equivalent to the specified path. (If
+ * you want an absolute path but don't mind links, use
+ * absolute_path().) The return value is a pointer to a static
+ * buffer.
+ *
+ * The input and all intermediate paths must be shorter than MAX_PATH.
+ * The directory part of path (i.e., everything up to the last
+ * dir_sep) must denote a valid, existing directory, but the last
+ * component need not exist. If die_on_error is set, then die with an
+ * informative error message if there is a problem. Otherwise, return
+ * NULL on errors (without generating any output).
*
* If path is our buffer, then return path, as it's already what the
* user wants.
*/
-const char *real_path(const char *path)
+static const char *real_path_internal(const char *path, int die_on_error)
{
static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
+ char *retval = NULL;
+
+ /*
+ * If we have to temporarily chdir(), store the original CWD
+ * here so that we can chdir() back to it at the end of the
+ * function:
+ */
char cwd[1024] = "";
+
int buf_index = 1;
int depth = MAXDEPTH;
@@ -35,11 +53,19 @@ const char *real_path(const char *path)
if (path == buf || path == next_buf)
return path;
- if (!*path)
- die("The empty string is not a valid path");
+ if (!*path) {
+ if (die_on_error)
+ die("The empty string is not a valid path");
+ else
+ goto error_out;
+ }
- if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
- die ("Too long path: %.*s", 60, path);
+ if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) {
+ if (die_on_error)
+ die("Too long path: %.*s", 60, path);
+ else
+ goto error_out;
+ }
while (depth--) {
if (!is_directory(buf)) {
@@ -54,20 +80,36 @@ const char *real_path(const char *path)
}
if (*buf) {
- if (!*cwd && !getcwd(cwd, sizeof(cwd)))
- die_errno ("Could not get current working directory");
+ if (!*cwd && !getcwd(cwd, sizeof(cwd))) {
+ if (die_on_error)
+ die_errno("Could not get current working directory");
+ else
+ goto error_out;
+ }
- if (chdir(buf))
- die_errno ("Could not switch to '%s'", buf);
+ if (chdir(buf)) {
+ if (die_on_error)
+ die_errno("Could not switch to '%s'", buf);
+ else
+ goto error_out;
+ }
+ }
+ if (!getcwd(buf, PATH_MAX)) {
+ if (die_on_error)
+ die_errno("Could not get current working directory");
+ else
+ goto error_out;
}
- if (!getcwd(buf, PATH_MAX))
- die_errno ("Could not get current working directory");
if (last_elem) {
size_t len = strlen(buf);
- if (len + strlen(last_elem) + 2 > PATH_MAX)
- die ("Too long path name: '%s/%s'",
- buf, last_elem);
+ if (len + strlen(last_elem) + 2 > PATH_MAX) {
+ if (die_on_error)
+ die("Too long path name: '%s/%s'",
+ buf, last_elem);
+ else
+ goto error_out;
+ }
if (len && !is_dir_sep(buf[len-1]))
buf[len++] = '/';
strcpy(buf + len, last_elem);
@@ -77,10 +119,18 @@ const char *real_path(const char *path)
if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
ssize_t len = readlink(buf, next_buf, PATH_MAX);
- if (len < 0)
- die_errno ("Invalid symlink '%s'", buf);
- if (PATH_MAX <= len)
- die("symbolic link too long: %s", buf);
+ if (len < 0) {
+ if (die_on_error)
+ die_errno("Invalid symlink '%s'", buf);
+ else
+ goto error_out;
+ }
+ if (PATH_MAX <= len) {
+ if (die_on_error)
+ die("symbolic link too long: %s", buf);
+ else
+ goto error_out;
+ }
next_buf[len] = '\0';
buf = next_buf;
buf_index = 1 - buf_index;
@@ -89,10 +139,23 @@ const char *real_path(const char *path)
break;
}
+ retval = buf;
+error_out:
+ free(last_elem);
if (*cwd && chdir(cwd))
die_errno ("Could not change back to '%s'", cwd);
- return buf;
+ return retval;
+}
+
+const char *real_path(const char *path)
+{
+ return real_path_internal(path, 1);
+}
+
+const char *real_path_if_valid(const char *path)
+{
+ return real_path_internal(path, 0);
}
static const char *get_pwd_cwd(void)