26772: better error handling and fix runaway chdir on failed cd

4 files changed, 31 insertions, 12 deletions

diff --git a/Src/Modules/files.c b/Src/Modules/files.c
index 0b991c556..3fbccf576 100644
--- a/Src/Modules/files.c
+++ b/Src/Modules/files.c
@@ -382,9 +382,7 @@ recursivecmd(char *nam, int opt_noerr, int opt_recurse, int opt_safe,
     reccmd.dirpost_func = dirpost_func;
     reccmd.leaf_func = leaf_func;
     reccmd.magic = magic;
-    ds.ino = ds.dev = 0;
-    ds.dirname = NULL;
-    ds.dirfd = ds.level = -1;
+    init_dirsav(&ds);
     if (opt_recurse || opt_safe) {
 	if ((ds.dirfd = open(".", O_RDONLY|O_NOCTTY)) < 0 &&
 	    zgetdir(&ds) && *ds.dirname != '/')
@@ -476,9 +474,7 @@ recursivecmd_dorec(struct recursivecmd const *reccmd,
     }
     err = err1;
 
-    dsav.ino = dsav.dev = 0;
-    dsav.dirname = NULL;
-    dsav.dirfd = dsav.level = -1;
+    init_dirsav(&dsav);
     d = opendir(".");
     if(!d) {
 	if(!reccmd->opt_noerr)
diff --git a/Src/glob.c b/Src/glob.c
index 5000ff457..46a0ce9c0 100644
--- a/Src/glob.c
+++ b/Src/glob.c
@@ -492,9 +492,7 @@ scanner(Complist q)
     int errssofar = errsfound;
     struct dirsav ds;
 
-    ds.ino = ds.dev = 0;
-    ds.dirname = NULL;
-    ds.dirfd = ds.level = -1;
+    init_dirsav(&ds);
     if (!q)
 	return;
 
diff --git a/Src/utils.c b/Src/utils.c
index 969f2cf09..9bf7878e0 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -5356,6 +5356,21 @@ upchdir(int n)
     return 0;
 }
 
+/*
+ * Initialize a "struct dirsav".
+ * The structure will be set to the directory we want to save
+ * the first time we change to a different directory.
+ */
+
+/**/
+mod_export void
+init_dirsav(Dirsav d)
+{
+    d->ino = d->dev = 0;
+    d->dirname = NULL;
+    d->dirfd = d->level = -1;
+}
+
 /* Change directory, without following symlinks.  Returns 0 on success, -1 *
  * on failure.  Sets errno to ENOTDIR if any symlinks are encountered.  If *
  * fchdir() fails, or the current directory is unreadable, we might end up *
@@ -5379,9 +5394,7 @@ lchdir(char const *path, struct dirsav *d, int hard)
 #endif
 
     if (!d) {
-	ds.ino = ds.dev = 0;
-	ds.dirname = NULL;
-	ds.dirfd = -1;
+	init_dirsav(&ds);
 	d = &ds;
     }
 #ifdef HAVE_LSTAT
@@ -5479,6 +5492,17 @@ lchdir(char const *path, struct dirsav *d, int hard)
 	}
     }
     if (restoredir(d)) {
+	int restoreerr = errno;
+	/*
+	 * Failed to restore the directory.
+	 * Just be definite, cd to root and report the result.
+	 */
+	zsfree(pwd);
+	pwd = ztrdup("/");
+	if (chdir(pwd) < 0)
+	    zerr("lost current directory, failed to cd to /: %e", errno);
+	else
+	    zerr("lost current directory: %e: changed to /", restoreerr);
 	if (d == &ds)
 	    zsfree(ds.dirname);
 #ifdef HAVE_FCHDIR
diff --git a/Src/zsh.h b/Src/zsh.h
index 8d2deec6c..3c1623c1f 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -382,6 +382,7 @@ typedef struct builtin   *Builtin;
 typedef struct cmdnam    *Cmdnam;
 typedef struct complist  *Complist;
 typedef struct conddef   *Conddef;
+typedef struct dirsav    *Dirsav;
 typedef struct features  *Features;
 typedef struct feature_enables  *Feature_enables;
 typedef struct funcstack *Funcstack;