[pulseaudio-discuss] [PATCH] udev-detect: don't use readdir_r(), it's deprecated

[Tanu Kaskinen]

readdir_r() was supposed to be a thread-safe version of readdir(), but
the interface turned out to be problematic. Due to the problems and the
fact that readdir() is safe enough on modern libc implementations, glibc
deprecated readdir_r() in version 2.24.

The man page contains more information about what's wrong with
readdir_r(): http://man7.org/linux/man-pages/man3/readdir_r.3.html
---
 src/modules/module-udev-detect.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/modules/module-udev-detect.c b/src/modules/module-udev-detect.c
index bb41a96..3d7064f 100644
--- a/src/modules/module-udev-detect.c
+++ b/src/modules/module-udev-detect.c
@@ -177,10 +177,8 @@ static bool is_card_busy(const char *id) {
     char *card_path = NULL, *pcm_path = NULL, *sub_status = NULL;
     DIR *card_dir = NULL, *pcm_dir = NULL;
     FILE *status_file = NULL;
-    size_t len;
-    struct dirent *space = NULL, *de;
+    struct dirent *de;
     bool busy = false;
-    int r;
 
     pa_assert(id);
 
@@ -194,14 +192,11 @@ static bool is_card_busy(const char *id) {
         goto fail;
     }
 
-    len = offsetof(struct dirent, d_name) + fpathconf(dirfd(card_dir), _PC_NAME_MAX) + 1;
-    space = pa_xmalloc(len);
-
     for (;;) {
-        de = NULL;
-
-        if ((r = readdir_r(card_dir, space, &de)) != 0) {
-            pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
+        errno = 0;
+        de = readdir(card_dir);
+        if (!de && errno) {
+            pa_log_warn("readdir() failed: %s", pa_cstrerror(errno));
             goto fail;
         }
 
@@ -228,8 +223,10 @@ static bool is_card_busy(const char *id) {
         for (;;) {
             char line[32];
 
-            if ((r = readdir_r(pcm_dir, space, &de)) != 0) {
-                pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
+            errno = 0;
+            de = readdir(pcm_dir);
+            if (!de && errno) {
+                pa_log_warn("readdir() failed: %s", pa_cstrerror(errno));
                 goto fail;
             }
 
@@ -267,7 +264,6 @@ fail:
     pa_xfree(card_path);
     pa_xfree(pcm_path);
     pa_xfree(sub_status);
-    pa_xfree(space);
 
     if (card_dir)
         closedir(card_dir);
-- 
2.9.3