Introduce new static function real_path_internal()
It accepts a new parameter, die_on_error. If die_on_error is false, it simply cleans up after itself and returns NULL rather than dying. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Jeff King <peff@peff.net>
Michael Haggerty committed
Oct 28, 2012 at 17:16 UTC
038e55fec2153a8195236d57dced4bbb001ccf3c
1 file changed
+72
-21
abspath.c
+72
-21
@@ -15,15 +15,26 @@ int is_directory(const char *path)
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#define MAXDEPTH 5
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/*
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- * Use this to get the real path, i.e. resolve links. If you want an
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- * absolute path but don't mind links, use absolute_path.
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+ * Return the real path (i.e., absolute path, with symlinks resolved
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+ * and extra slashes removed) equivalent to the specified path. (If
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+ * you want an absolute path but don't mind links, use
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+ * absolute_path().) The return value is a pointer to a static
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+ * buffer.
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+ *
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+ * The input and all intermediate paths must be shorter than MAX_PATH.
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+ * The directory part of path (i.e., everything up to the last
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+ * dir_sep) must denote a valid, existing directory, but the last
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+ * component need not exist. If die_on_error is set, then die with an
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+ * informative error message if there is a problem. Otherwise, return
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+ * NULL on errors (without generating any output).
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*
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* If path is our buffer, then return path, as it's already what the
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* user wants.
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*/
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-const char *real_path(const char *path)
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+static const char *real_path_internal(const char *path, int die_on_error)
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{
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static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
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+ char *retval = NULL;
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char cwd[1024] = "";
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int buf_index = 1;
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@@ -35,11 +46,19 @@ const char *real_path(const char *path)
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if (path == buf || path == next_buf)
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return path;
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- if (!*path)
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- die("The empty string is not a valid path");
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+ if (!*path) {
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+ if (die_on_error)
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+ die("The empty string is not a valid path");
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+ else
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+ goto error_out;
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+ }
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- if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
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- die ("Too long path: %.*s", 60, path);
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+ if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) {
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+ if (die_on_error)
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+ die("Too long path: %.*s", 60, path);
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+ else
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+ goto error_out;
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+ }
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while (depth--) {
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if (!is_directory(buf)) {
@@ -54,20 +73,36 @@ const char *real_path(const char *path)
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}
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if (*buf) {
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- if (!*cwd && !getcwd(cwd, sizeof(cwd)))
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- die_errno ("Could not get current working directory");
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+ if (!*cwd && !getcwd(cwd, sizeof(cwd))) {
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+ if (die_on_error)
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+ die_errno("Could not get current working directory");
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+ else
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+ goto error_out;
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+ }
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- if (chdir(buf))
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- die_errno ("Could not switch to '%s'", buf);
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+ if (chdir(buf)) {
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+ if (die_on_error)
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+ die_errno("Could not switch to '%s'", buf);
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+ else
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+ goto error_out;
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+ }
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+ }
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+ if (!getcwd(buf, PATH_MAX)) {
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+ if (die_on_error)
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+ die_errno("Could not get current working directory");
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+ else
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+ goto error_out;
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}
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- if (!getcwd(buf, PATH_MAX))
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- die_errno ("Could not get current working directory");
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if (last_elem) {
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size_t len = strlen(buf);
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- if (len + strlen(last_elem) + 2 > PATH_MAX)
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- die ("Too long path name: '%s/%s'",
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- buf, last_elem);
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+ if (len + strlen(last_elem) + 2 > PATH_MAX) {
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+ if (die_on_error)
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+ die("Too long path name: '%s/%s'",
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+ buf, last_elem);
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+ else
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+ goto error_out;
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+ }
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if (len && !is_dir_sep(buf[len-1]))
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buf[len++] = '/';
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strcpy(buf + len, last_elem);
@@ -77,10 +112,18 @@ const char *real_path(const char *path)
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if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
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ssize_t len = readlink(buf, next_buf, PATH_MAX);
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- if (len < 0)
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- die_errno ("Invalid symlink '%s'", buf);
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- if (PATH_MAX <= len)
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- die("symbolic link too long: %s", buf);
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+ if (len < 0) {
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+ if (die_on_error)
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+ die_errno("Invalid symlink '%s'", buf);
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+ else
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+ goto error_out;
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+ }
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+ if (PATH_MAX <= len) {
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+ if (die_on_error)
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+ die("symbolic link too long: %s", buf);
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+ else
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+ goto error_out;
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+ }
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next_buf[len] = '\0';
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buf = next_buf;
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buf_index = 1 - buf_index;
@@ -89,10 +132,18 @@ const char *real_path(const char *path)
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break;
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}
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+ retval = buf;
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+error_out:
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+ free(last_elem);
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if (*cwd && chdir(cwd))
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die_errno ("Could not change back to '%s'", cwd);
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- return buf;
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+ return retval;
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+}
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+
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+const char *real_path(const char *path)
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+{
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+ return real_path_internal(path, 1);
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}
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static const char *get_pwd_cwd(void)