From a7e08e893eb796637ca2c53cd32a529f453ace12 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Mon, 14 Nov 2016 22:40:40 -0500
Subject: Check for readdir() errors everywhere.

---
 bftw.c | 16 ++--------------
 eval.c | 20 ++++++++++++++++----
 util.c | 10 ++++++++++
 util.h |  6 ++++++
 4 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/bftw.c b/bftw.c
index 630c643..e2bfcc6 100644
--- a/bftw.c
+++ b/bftw.c
@@ -22,6 +22,7 @@
 
 #include "bftw.h"
 #include "dstring.h"
+#include "util.h"
 #include <assert.h>
 #include <dirent.h>
 #include <errno.h>
@@ -867,19 +868,6 @@ static struct dircache_entry *bftw_add(struct bftw_state *state, const char *nam
 	return entry;
 }
 
-/**
- * readdir() wrapper that makes error handling cleaner.
- */
-static int bftw_readdir(DIR *dir, struct dirent **de) {
-	errno = 0;
-	*de = readdir(dir);
-	if (!*de && errno != 0) {
-		return -1;
-	} else {
-		return 0;
-	}
-}
-
 /**
  * Push a new entry onto the queue.
  */
@@ -1016,7 +1004,7 @@ int bftw(const char *path, bftw_fn *fn, int nopenfd, enum bftw_flags flags, void
 
 		while (true) {
 			struct dirent *de;
-			if (bftw_readdir(dir, &de) != 0) {
+			if (xreaddir(dir, &de) != 0) {
 				goto dir_error;
 			}
 			if (!de) {
diff --git a/eval.c b/eval.c
index 1e88a93..80df040 100644
--- a/eval.c
+++ b/eval.c
@@ -498,14 +498,23 @@ bool eval_empty(const struct expr *expr, struct eval_state *state) {
 
 		ret = true;
 
-		struct dirent *de;
-		while ((de = readdir(dir)) != NULL) {
+		while (true) {
+			struct dirent *de;
+			if (xreaddir(dir, &de) != 0) {
+				eval_error(state);
+				goto done_dir;
+			}
+			if (!de) {
+				break;
+			}
+
 			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
 				ret = false;
 				break;
 			}
 		}
 
+	done_dir:
 		closedir(dir);
 	} else {
 		const struct stat *statbuf = fill_statbuf(state);
@@ -1038,8 +1047,11 @@ static int infer_fdlimit(const struct cmdline *cmdline) {
 		// Account for 'dir' itself
 		nopen = -1;
 
-		struct dirent *de;
-		while ((de = readdir(dir)) != NULL) {
+		while (true) {
+			struct dirent *de;
+			if (xreaddir(dir, &de) != 0 || !de) {
+				break;
+			}
 			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
 				++nopen;
 			}
diff --git a/util.c b/util.c
index e0f6177..aef5fbb 100644
--- a/util.c
+++ b/util.c
@@ -17,6 +17,16 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+int xreaddir(DIR *dir, struct dirent **de) {
+	errno = 0;
+	*de = readdir(dir);
+	if (!*de && errno != 0) {
+		return -1;
+	} else {
+		return 0;
+	}
+}
+
 bool isopen(int fd) {
 	return fcntl(fd, F_GETFD) >= 0 || errno != EBADF;
 }
diff --git a/util.h b/util.h
index c3b3dbe..fbcadbd 100644
--- a/util.h
+++ b/util.h
@@ -12,8 +12,14 @@
 #ifndef BFS_UTIL_H
 #define BFS_UTIL_H
 
+#include <dirent.h>
 #include <stdbool.h>
 
+/**
+ * readdir() wrapper that makes error handling cleaner.
+ */
+int xreaddir(DIR *dir, struct dirent **de);
+
 /**
  * Check if a file descriptor is open.
  */
-- 
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