From aab9164df395a4b0878b0ad930a5ec8a806a58e9 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Sat, 9 May 2015 18:11:22 -0500
Subject: Add DIRTREE_SHUTUP to disable dirtree warnings if file vanishes out
 from under traversal. Pass through full flag set in dirtree_add_node(), add
 dirtree_start() wrapper to provide symlink-only behavior (avoiding a lot of
 DIRTREE_SYMFOLLOW*!!(logic) repeated in callers).

---
 lib/dirtree.c | 41 +++++++++++++++++++++++------------------
 lib/lib.h     |  5 ++++-
 2 files changed, 27 insertions(+), 19 deletions(-)

(limited to 'lib')

diff --git a/lib/dirtree.c b/lib/dirtree.c
index 60ce56b8..1e898161 100644
--- a/lib/dirtree.c
+++ b/lib/dirtree.c
@@ -24,22 +24,21 @@ int dirtree_notdotdot(struct dirtree *catch)
 // (This doesn't open directory filehandles yet so as not to exhaust the
 // filehandle space on large trees, dirtree_handle_callback() does that.)
 
-struct dirtree *dirtree_add_node(struct dirtree *parent, char *name,
-  int symfollow)
+struct dirtree *dirtree_add_node(struct dirtree *parent, char *name, int flags)
 {
   struct dirtree *dt = NULL;
   struct stat st;
-  char buf[4096];
   int len = 0, linklen = 0;
 
   if (name) {
     // open code this because haven't got node to call dirtree_parentfd() on yet
     int fd = parent ? parent->data : AT_FDCWD;
 
-    if (fstatat(fd, name, &st, symfollow ? 0 : AT_SYMLINK_NOFOLLOW)) goto error;
+    if (fstatat(fd, name, &st, AT_SYMLINK_NOFOLLOW*!(flags&DIRTREE_SYMFOLLOW)))
+      goto error;
     if (S_ISLNK(st.st_mode)) {
-      if (0>(linklen = readlinkat(fd, name, buf, 4095))) goto error;
-      buf[linklen++]=0;
+      if (0>(linklen = readlinkat(fd, name, libbuf, 4095))) goto error;
+      libbuf[linklen++]=0;
     }
     len = strlen(name);
   }
@@ -50,7 +49,7 @@ struct dirtree *dirtree_add_node(struct dirtree *parent, char *name,
     strcpy(dt->name, name);
 
     if (linklen) {
-      dt->symlink = memcpy(len+(char *)dt, buf, linklen);
+      dt->symlink = memcpy(len+(char *)dt, libbuf, linklen);
       dt->data = --linklen;
     }
   }
@@ -58,7 +57,7 @@ struct dirtree *dirtree_add_node(struct dirtree *parent, char *name,
   return dt;
 
 error:
-  if (notdotdot(name)) {
+  if (!(flags&DIRTREE_SHUTUP) && notdotdot(name)) {
     char *path = parent ? dirtree_path(parent, 0) : "";
 
     perror_msg("%s%s%s", path, parent ? "/" : "", name);
@@ -111,13 +110,13 @@ int dirtree_parentfd(struct dirtree *node)
 struct dirtree *dirtree_handle_callback(struct dirtree *new,
           int (*callback)(struct dirtree *node))
 {
-  int flags, dir = S_ISDIR(new->st.st_mode);
+  int flags;
 
+  if (!new) return 0;
   if (!callback) callback = dirtree_notdotdot;
-
   flags = callback(new);
 
-  if (dir) {
+  if (S_ISDIR(new->st.st_mode)) {
     if (flags & (DIRTREE_RECURSE|DIRTREE_COMEAGAIN)) {
       new->data = openat(dirtree_parentfd(new), new->name, O_CLOEXEC);
       flags = dirtree_recurse(new, callback, flags);
@@ -144,9 +143,11 @@ int dirtree_recurse(struct dirtree *node,
   DIR *dir;
 
   if (node->data == -1 || !(dir = fdopendir(node->data))) {
-    char *path = dirtree_path(node, 0);
-    perror_msg("No %s", path);
-    free(path);
+    if (!(flags & DIRTREE_SHUTUP)) {
+      char *path = dirtree_path(node, 0);
+      perror_msg("No %s", path);
+      free(path);
+    }
     close(node->data);
 
     return flags;
@@ -157,8 +158,7 @@ int dirtree_recurse(struct dirtree *node,
 
   // The extra parentheses are to shut the stupid compiler up.
   while ((entry = readdir(dir))) {
-    if (!(new = dirtree_add_node(node, entry->d_name, flags&DIRTREE_SYMFOLLOW)))
-      continue;
+    if (!(new = dirtree_add_node(node, entry->d_name, flags))) continue;
     new = dirtree_handle_callback(new, callback);
     if (new == DIRTREE_ABORTVAL) break;
     if (new) {
@@ -179,14 +179,19 @@ int dirtree_recurse(struct dirtree *node,
   return flags;
 }
 
+// Create dirtree root
+struct dirtree *dirtree_start(char *name, int symfollow)
+{
+  return dirtree_add_node(0, name, DIRTREE_SYMFOLLOW*!!symfollow);
+}
+
 // Create dirtree from path, using callback to filter nodes.
 // If callback == NULL allocate a tree of struct dirtree nodes and return
 // pointer to root node.
-// symfollow is just for the top of tree, callback return code controls children
 
 struct dirtree *dirtree_read(char *path, int (*callback)(struct dirtree *node))
 {
-  struct dirtree *root = dirtree_add_node(0, path, 0);
+  struct dirtree *root = dirtree_start(path, 0);
 
   return root ? dirtree_handle_callback(root, callback) : DIRTREE_ABORTVAL;
 }
diff --git a/lib/lib.h b/lib/lib.h
index be4051eb..03a05703 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -50,6 +50,8 @@ void get_optflags(void);
 #define DIRTREE_COMEAGAIN    4
 // Follow symlinks to directories
 #define DIRTREE_SYMFOLLOW    8
+// Don't warn about failure to stat
+#define DIRTREE_SHUTUP      16
 // Don't look at any more files in this directory.
 #define DIRTREE_ABORT      256
 
@@ -65,7 +67,8 @@ struct dirtree {
   char name[];
 };
 
-struct dirtree *dirtree_add_node(struct dirtree *p, char *name, int symfollow);
+struct dirtree *dirtree_start(char *name, int symfollow);
+struct dirtree *dirtree_add_node(struct dirtree *p, char *name, int flags);
 char *dirtree_path(struct dirtree *node, int *plen);
 int dirtree_notdotdot(struct dirtree *catch);
 int dirtree_parentfd(struct dirtree *node);
-- 
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