tools: Introduce str_error_r()

The tools so far have been using the strerror_r() GNU variant, that
returns a string, be it the buffer passed or something else.

But that, besides being tricky in cases where we expect that the
function using strerror_r() returns the error formatted in a provided
buffer (we have to check if it returned something else and copy that
instead), breaks the build on systems not using glibc, like Alpine
Linux, where musl libc is used.

So, introduce yet another wrapper, str_error_r(), that has the GNU
interface, but uses the portable XSI variant of strerror_r(), so that
users rest asured that the provided buffer is used and it is what is
returned.

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-d4t42fnf48ytlk8rjxs822tf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 07fc7921980c..bd108683fcb8 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -907,7 +907,7 @@ try_again:
 
         if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) {
                 ui__error("Failed to mmap with %d (%s)\n",
-                            errno, strerror_r(errno, msg, sizeof(msg)));
+                            errno, str_error_r(errno, msg, sizeof(msg)));
                 goto out_err;
         }
 
@@ -1028,7 +1028,7 @@ out_delete:
 
 out_err_cpu_topo: {
         char errbuf[BUFSIZ];
-        const char *err = strerror_r(-ret, errbuf, sizeof(errbuf));
+        const char *err = str_error_r(-ret, errbuf, sizeof(errbuf));
 
         ui__error("Could not read the CPU topology map: %s\n", err);
         goto out_delete;
@@ -1295,7 +1295,7 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
 
         if (perf_evlist__create_maps(top.evlist, target) < 0) {
                 ui__error("Couldn't create thread/CPU maps: %s\n",
-                          errno == ENOENT ? "No such process" : strerror_r(errno, errbuf, sizeof(errbuf)));
+                          errno == ENOENT ? "No such process" : str_error_r(errno, errbuf, sizeof(errbuf)));
                 goto out_delete_evlist;
         }