From cd3f81ebe5c82f1fd5f610b0f2e0fa07ac27903e Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sun, 8 Apr 2018 20:50:10 -0500
Subject: Add readlink -m to show where a missing path would be.

Note: ubuntu will show -m through a file, this treat that as error.
---
 lib/xwrap.c | 49 +++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

(limited to 'lib/xwrap.c')

diff --git a/lib/xwrap.c b/lib/xwrap.c
index 562cbaf4..54985db3 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -481,7 +481,7 @@ void xstat(char *path, struct stat *st)
 char *xabspath(char *path, int exact)
 {
   struct string_list *todo, *done = 0;
-  int try = 9999, dirfd = open("/", 0);;
+  int try = 9999, dirfd = open("/", 0), missing = 0;
   char *ret;
 
   // If this isn't an absolute path, start with cwd.
@@ -492,11 +492,12 @@ char *xabspath(char *path, int exact)
     free(temp);
   } else splitpath(path, &todo);
 
-  // Iterate through path components
+  // Iterate through path components in todo, prepend processed ones to done.
   while (todo) {
     struct string_list *new = llist_pop(&todo), **tail;
     ssize_t len;
 
+    // Eventually break out of endless loops
     if (!try--) {
       errno = ELOOP;
       goto error;
@@ -507,29 +508,37 @@ char *xabspath(char *path, int exact)
       int x = new->str[1];
 
       free(new);
-      if (x) {
-        if (done) free(llist_pop(&done));
-        len = 0;
-      } else continue;
+      if (!x) continue;
+      if (done) free(llist_pop(&done));
+      len = 0;
+
+      if (missing) missing--;
+      else {
+        if (-1 == (x = openat(dirfd, "..", 0))) goto error;
+        close(dirfd);
+        dirfd = x;
+      }
+      continue;
+    }
 
     // Is this a symlink?
-    } else len = readlinkat(dirfd, new->str, libbuf, sizeof(libbuf));
-
+    len = readlinkat(dirfd, new->str, libbuf, sizeof(libbuf));
     if (len>4095) goto error;
+
+    // Not a symlink: add to linked list, move dirfd, fail if error
     if (len<1) {
       int fd;
-      char *s = "..";
-
-      // For .. just move dirfd
-      if (len) {
-        // Not a symlink: add to linked list, move dirfd, fail if error
-        if ((exact || todo) && errno != EINVAL) goto error;
-        new->next = done;
-        done = new;
-        if (errno == EINVAL && !todo) break;
-        s = new->str;
+
+      new->next = done;
+      done = new;
+      if (errno == EINVAL && !todo) break;
+      if (errno == ENOENT && exact<0) {
+        missing++;
+        continue;
       }
-      fd = openat(dirfd, s, 0);
+      if (errno != EINVAL && (exact || todo)) goto error;
+
+      fd = openat(dirfd, new->str, 0);
       if (fd == -1 && (exact || todo || errno != ENOENT)) goto error;
       close(dirfd);
       dirfd = fd;
@@ -588,7 +597,7 @@ error:
   llist_traverse(todo, free);
   llist_traverse(done, free);
 
-  return NULL;
+  return 0;
 }
 
 void xchdir(char *path)
-- 
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