[hackers] [sbase] ls: detect infinite loop with recursivity || Quentin Rameau

From: <git_AT_suckless.org>
Date: Mon, 31 Aug 2015 19:10:51 +0200 (CEST)

commit f1bbe6529ab0a092731e5fa8ec9bf7d82a806f69
Author: Quentin Rameau <quinq_AT_quinq.eu.org>
AuthorDate: Fri Jun 12 20:03:04 2015 +0200
Commit: sin <sin_AT_2f30.org>
CommitDate: Mon Aug 31 18:10:25 2015 +0100

    ls: detect infinite loop with recursivity
    
    populate an history of visited directories inodes and search it before
    recursing

diff --git a/ls.c b/ls.c
index e726a7e..bb44357 100644
--- a/ls.c
+++ b/ls.c
_AT_@ -21,9 +21,15 @@ struct entry {
         gid_t gid;
         off_t size;
         time_t t;
- ino_t ino;
+ dev_t dev;
+ ino_t ino, tino;
 };
 
+static struct {
+ dev_t dev;
+ ino_t ino;
+} tree[PATH_MAX] = { { 0, 0 } };
+
 static int Aflag = 0;
 static int aflag = 0;
 static int cflag = 0;
_AT_@ -69,9 +75,17 @@ mkent(struct entry *ent, char *path, int dostat, int follow)
                 ent->t = st.st_atime;
         else
                 ent->t = st.st_mtime;
+ ent->dev = st.st_dev;
         ent->ino = st.st_ino;
- if (S_ISLNK(ent->mode))
- ent->tmode = stat(path, &st) == 0 ? st.st_mode : 0;
+ if (S_ISLNK(ent->mode)) {
+ if (stat(path, &st) == 0) {
+ ent->tmode = st.st_mode;
+ ent->dev = st.st_dev;
+ ent->tino = st.st_ino;
+ } else {
+ ent->tmode = ent->tino = 0;
+ }
+ }
 }
 
 static char *
_AT_@ -270,15 +284,42 @@ lsdir(const char *path, const struct entry *dir)
         free(ents);
 }
 
+static int
+visit(const struct entry *ent)
+{
+ dev_t dev;
+ ino_t ino;
+ int i;
+
+ dev = ent->dev;
+ ino = S_ISLNK(ent->mode) ? ent->tino : ent->ino;
+
+ for (i = 0; tree[i].ino && i < PATH_MAX; ++i) {
+ if (ino == tree[i].ino && dev == tree[i].dev)
+ return -1;
+ }
+
+ tree[i].ino = ino;
+ tree[i].dev = dev;
+ return i;
+}
+
 static void
 ls(const char *path, const struct entry *ent, int listdir)
 {
+ int treeind;
         char cwd[PATH_MAX];
 
         if (!listdir) {
                 output(ent);
         } else if (S_ISDIR(ent->mode) ||
             (S_ISLNK(ent->mode) && S_ISDIR(ent->tmode))) {
+ if ((treeind = visit(ent)) < 0) {
+ fprintf(stderr, "%s%s: already visited\n",
+ path, ent->name);
+ return;
+ }
+
                 if (!getcwd(cwd, PATH_MAX))
                         eprintf("getcwd:");
 
_AT_@ -289,6 +330,7 @@ ls(const char *path, const struct entry *ent, int listdir)
 
                 printf("%s", path);
                 lsdir(path, ent);
+ tree[treeind].ino = 0;
 
                 if (chdir(cwd) < 0)
                         eprintf("chdir %s:", cwd);
Received on Mon Aug 31 2015 - 19:10:51 CEST