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

[Arun Raghavan]

On Thu, 13 Oct 2016, at 07:52 PM, Tanu Kaskinen wrote:
> 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);
> -- 

LGTM.

-- Arun