| From: Arnaldo Carvalho de Melo <acme@redhat.com> |
| Date: Fri, 8 Apr 2016 11:31:24 -0300 |
| Subject: perf thread_map: Use readdir() instead of deprecated readdir_r() |
| |
| commit 3354cf71104de49326d19d2f9bdb1f66eea52ef4 upstream. |
| |
| The readdir() function is thread safe as long as just one thread uses a |
| DIR, which is the case in thread_map, so, to avoid breaking the build |
| with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r(). |
| |
| See: http://man7.org/linux/man-pages/man3/readdir.3.html |
| |
| "However, in modern implementations (including the glibc implementation), |
| concurrent calls to readdir() that specify different directory streams |
| are thread-safe. In cases where multiple threads must read from the |
| same directory stream, using readdir() with external synchronization is |
| still preferable to the use of the deprecated readdir_r(3) function." |
| |
| Noticed while building on a Fedora Rawhide docker container. |
| |
| Cc: Adrian Hunter <adrian.hunter@intel.com> |
| Cc: David Ahern <dsahern@gmail.com> |
| Cc: Jiri Olsa <jolsa@kernel.org> |
| Cc: Namhyung Kim <namhyung@kernel.org> |
| Cc: Wang Nan <wangnan0@huawei.com> |
| Link: http://lkml.kernel.org/n/tip-del8h2a0f40z75j4r42l96l0@git.kernel.org |
| Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
| [bwh: Backported to 3.16: adjust context] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| tools/perf/util/thread_map.c | 8 ++++---- |
| 1 file changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/tools/perf/util/thread_map.c |
| +++ b/tools/perf/util/thread_map.c |
| @@ -64,7 +64,7 @@ struct thread_map *thread_map__new_by_ui |
| DIR *proc; |
| int max_threads = 32, items, i; |
| char path[256]; |
| - struct dirent dirent, *next, **namelist = NULL; |
| + struct dirent *dirent, **namelist = NULL; |
| struct thread_map *threads = malloc(sizeof(*threads) + |
| max_threads * sizeof(pid_t)); |
| if (threads == NULL) |
| @@ -76,16 +76,16 @@ struct thread_map *thread_map__new_by_ui |
| |
| threads->nr = 0; |
| |
| - while (!readdir_r(proc, &dirent, &next) && next) { |
| + while ((dirent = readdir(proc)) != NULL) { |
| char *end; |
| bool grow = false; |
| struct stat st; |
| - pid_t pid = strtol(dirent.d_name, &end, 10); |
| + pid_t pid = strtol(dirent->d_name, &end, 10); |
| |
| if (*end) /* only interested in proper numerical dirents */ |
| continue; |
| |
| - snprintf(path, sizeof(path), "/proc/%s", dirent.d_name); |
| + snprintf(path, sizeof(path), "/proc/%s", dirent->d_name); |
| |
| if (stat(path, &st) != 0) |
| continue; |