perf buildid-cache: Fix symbolic link handling

This was broken since link(2) doesn't dereference symbolic
links. Instead 'filename' becomes a symbolic link to the same file
that 'name' refers to.

This had the bad effect to create dangling symlinks in the case that
even can't be removed with perf-buildid-cache(1).

LKML-Reference: <m38vzxxrql.fsf@gmail.com>
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 64a85bafde63..7cba0551a565 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -265,15 +265,16 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
                           const char *name, bool is_kallsyms)
 {
         const size_t size = PATH_MAX;
-        char *filename = malloc(size),
+        char *realname = realpath(name, NULL),
+             *filename = malloc(size),
              *linkname = malloc(size), *targetname;
         int len, err = -1;
 
-        if (filename == NULL || linkname == NULL)
+        if (realname == NULL || filename == NULL || linkname == NULL)
                 goto out_free;
 
         len = snprintf(filename, size, "%s%s%s",
-                       debugdir, is_kallsyms ? "/" : "", name);
+                       debugdir, is_kallsyms ? "/" : "", realname);
         if (mkdir_p(filename, 0755))
                 goto out_free;
 
@@ -283,7 +284,7 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
                 if (is_kallsyms) {
                          if (copyfile("/proc/kallsyms", filename))
                                 goto out_free;
-                } else if (link(name, filename) && copyfile(name, filename))
+                } else if (link(realname, filename) && copyfile(name, filename))
                         goto out_free;
         }
 
@@ -300,6 +301,7 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
         if (symlink(targetname, linkname) == 0)
                 err = 0;
 out_free:
+        free(realname);
         free(filename);
         free(linkname);
         return err;