perf buildid-cache: Add new command to manage build-id cache

For now it just has operations to examine a given file, find its
build-id and add or remove it to/from the cache.

Useful, for instance, when adding binaries sent together with a
perf.data file, so that we can add them to the cache and have
the tools find it when resolving symbols.

It'll also manage the size of the cache like 'ccache' does.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1264008525-29025-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 63 insertions, 9 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 1b65fed0dd2d..2bb2bdb1f456 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -231,32 +231,29 @@ static int dsos__write_buildid_table(int fd)
         return err;
 }
 
-static int dso__cache_build_id(struct dso *self, const char *debugdir)
+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),
-             *linkname = malloc(size), *targetname, *sbuild_id;
+             *linkname = malloc(size), *targetname;
         int len, err = -1;
-        bool is_kallsyms = self->kernel && self->long_name[0] != '/';
 
         if (filename == NULL || linkname == NULL)
                 goto out_free;
 
         len = snprintf(filename, size, "%s%s%s",
-                       debugdir, is_kallsyms ? "/" : "", self->long_name);
+                       debugdir, is_kallsyms ? "/" : "", name);
         if (mkdir_p(filename, 0755))
                 goto out_free;
 
-        len += snprintf(filename + len, sizeof(filename) - len, "/");
-        sbuild_id = filename + len;
-        build_id__sprintf(self->build_id, sizeof(self->build_id), sbuild_id);
+        snprintf(filename + len, sizeof(filename) - len, "/%s", sbuild_id);
 
         if (access(filename, F_OK)) {
                 if (is_kallsyms) {
                          if (copyfile("/proc/kallsyms", filename))
                                 goto out_free;
-                } else if (link(self->long_name, filename) &&
-                           copyfile(self->long_name, filename))
+                } else if (link(name, filename) && copyfile(name, filename))
                         goto out_free;
         }
 
@@ -278,6 +275,63 @@ out_free:
         return err;
 }
 
+static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
+                                 const char *name, const char *debugdir,
+                                 bool is_kallsyms)
+{
+        char sbuild_id[BUILD_ID_SIZE * 2 + 1];
+
+        build_id__sprintf(build_id, build_id_size, sbuild_id);
+
+        return build_id_cache__add_s(sbuild_id, debugdir, name, is_kallsyms);
+}
+
+int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir)
+{
+        const size_t size = PATH_MAX;
+        char *filename = malloc(size),
+             *linkname = malloc(size);
+        int err = -1;
+
+        if (filename == NULL || linkname == NULL)
+                goto out_free;
+
+        snprintf(linkname, size, "%s/.build-id/%.2s/%s",
+                 debugdir, sbuild_id, sbuild_id + 2);
+
+        if (access(linkname, F_OK))
+                goto out_free;
+
+        if (readlink(linkname, filename, size) < 0)
+                goto out_free;
+
+        if (unlink(linkname))
+                goto out_free;
+
+        /*
+         * Since the link is relative, we must make it absolute:
+         */
+        snprintf(linkname, size, "%s/.build-id/%.2s/%s",
+                 debugdir, sbuild_id, filename);
+
+        if (unlink(linkname))
+                goto out_free;
+
+        err = 0;
+out_free:
+        free(filename);
+        free(linkname);
+        return err;
+}
+
+static int dso__cache_build_id(struct dso *self, const char *debugdir)
+{
+        bool is_kallsyms = self->kernel && self->long_name[0] != '/';
+
+        return build_id_cache__add_b(self->build_id, sizeof(self->build_id),
+                                     self->long_name, debugdir, is_kallsyms);
+}
+
 static int __dsos__cache_build_ids(struct list_head *head, const char *debugdir)
 {
         struct dso *pos;