[hackers] [quark] Fix normabspath() to handle consecutive '..'s properly || Laslo Hunhold

From: <git_AT_suckless.org>
Date: Wed, 21 Jun 2017 11:03:27 +0200 (CEST)

commit bd2e9e66ffda25e583b2978d1f84163b15f301db
Author: Laslo Hunhold <dev_AT_frign.de>
AuthorDate: Wed Jun 21 11:02:35 2017 +0200
Commit: Laslo Hunhold <dev_AT_frign.de>
CommitDate: Wed Jun 21 11:02:35 2017 +0200

    Fix normabspath() to handle consecutive '..'s properly
    
    The approach with lastp only works if we only go back one dir at a time.
    Of course, this cannot be assumed, so we traverse the path backwards
    looking for the previous /.

diff --git a/quark.c b/quark.c
index 4d056d3..de41214 100644
--- a/quark.c
+++ b/quark.c
_AT_@ -460,8 +460,8 @@ static int
 normabspath(char *path)
 {
         size_t len;
- int done = 0;
- char *p, *q, *lastp;
+ int last = 0;
+ char *p, *q;
 
         /* require and skip first slash */
         if (path[0] != '/') {
_AT_@ -472,25 +472,37 @@ normabspath(char *path)
         /* get length of path */
         len = strlen(p);
 
- for (lastp = p; !done; ) {
+ for (; !last; ) {
                 /* bound path component within (p,q) */
                 if (!(q = strchr(p, '/'))) {
                         q = strchr(p, '\0');
- done = 1;
+ last = 1;
                 }
 
                 if (p == q || (q - p == 1 && p[0] == '.')) {
                         /* "/" or "./" */
- memcpy(p, q + 1, len - ((q + 1) - path) + 2);
- len -= (q + 1) - p;
+ goto squash;
                 } else if (q - p == 2 && p[0] == '.' && p[1] == '.') {
                         /* "../" */
- memcpy(lastp, q + 1, len - ((q + 1) - path) + 2);
- len -= (q + 1) - lastp;
- p = lastp;
+ if (p != path + 1) {
+ /* place p right after the previous / */
+ for (p -= 2; p > path && *p != '/'; p--);
+ p++;
+ }
+ goto squash;
                 } else {
- lastp = p;
+ /* move on */
                         p = q + 1;
+ continue;
+ }
+squash:
+ /* squash (p,q) into void */
+ if (last) {
+ *p = '\0';
+ len = p - path;
+ } else {
+ memcpy(p, q + 1, len - ((q + 1) - path) + 2);
+ len -= (q + 1) - p;
                 }
         }
 
Received on Wed Jun 21 2017 - 11:03:27 CEST