[perf/core PATCH v4 2/2] perf buildid-cache: Add --purge FILE to remove all caches of FILE

[Masami Hiramatsu]

Add --purge FILE to remove all caches of FILE.
Since the current --remove FILE removes a cache which has
same build-id of given FILE. Since the command takes a
FILE path, it can confuse user who tries to remove cache
about FILE path.

  -----
  # ./perf buildid-cache -v --add ./perf
  Adding 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  # (update the ./perf binary)
  # ./perf buildid-cache -v --remove ./perf
  Removing 305bbd1be68f66eca7e2d78db294653031edfa79 ./perf: FAIL
  ./perf wasn't in the cache
  -----
Actually, the --remove's FAIL is not shown, it just silently fails.

So, this patch adds --purge FILE action for such usecase.
perf buildid-cache --purge FILE removes all caches which
has same FILE path.
In other words, it removes all caches including old binaries.

  -----
  # ./perf buildid-cache -v --add ./perf
  Adding 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  # (update the ./perf binary)
  # ./perf buildid-cache -v --purge ./perf
  Removing 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  -----

BTW, if you want to purge all the caches, remove ~/.debug/* .

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
---
 tools/perf/Documentation/perf-buildid-cache.txt |   13 ++-
 tools/perf/builtin-buildid-cache.c              |   44 ++++++++++++
 tools/perf/util/build-id.c                      |   86 ++++++++++++++++++-----
 tools/perf/util/build-id.h                      |    1 
 4 files changed, 123 insertions(+), 21 deletions(-)

diff --git a/tools/perf/Documentation/perf-buildid-cache.txt b/tools/perf/Documentation/perf-buildid-cache.txt
index cec6b57..dd07b55 100644
--- a/tools/perf/Documentation/perf-buildid-cache.txt
+++ b/tools/perf/Documentation/perf-buildid-cache.txt
@@ -12,9 +12,9 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-This command manages the build-id cache. It can add and remove files to/from
-the cache. In the future it should as well purge older entries, set upper
-limits for the space used by the cache, etc.
+This command manages the build-id cache. It can add, remove, update and purge
+files to/from the cache. In the future it should as well set upper limits for
+the space used by the cache, etc.
 
 OPTIONS
 -------
@@ -36,7 +36,12 @@ OPTIONS
         actually made.
 -r::
 --remove=::
-        Remove specified file from the cache.
+        Remove a cached binary which has same build-id of specified file
+        from the cache.
+-p::
+--purge=::
+        Purge all cached binaries including older caches which have specified
+	path from the cache.
 -M::
 --missing=::
 	List missing build ids in the cache for the specified file.
diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index e7568f5..37182bb 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -223,6 +223,29 @@ static int build_id_cache__remove_file(const char *filename)
 	return err;
 }
 
+static int build_id_cache__purge_path(const char *pathname)
+{
+	struct strlist *list;
+	struct str_node *pos;
+	int err;
+
+	list = build_id_cache__list_build_ids(pathname);
+	if (!list)
+		return 0;
+
+	strlist__for_each(pos, list) {
+		err = build_id_cache__remove_s(pos->s);
+		if (verbose)
+			pr_info("Removing %s %s: %s\n", pos->s, pathname,
+				err ? "FAIL" : "Ok");
+		if (err)
+			break;
+	}
+	strlist__delete(list);
+
+	return err;
+}
+
 static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
 {
 	char filename[PATH_MAX];
@@ -285,6 +308,7 @@ int cmd_buildid_cache(int argc, const char **argv,
 	bool force = false;
 	char const *add_name_list_str = NULL,
 		   *remove_name_list_str = NULL,
+		   *purge_name_list_str = NULL,
 		   *missing_filename = NULL,
 		   *update_name_list_str = NULL,
 		   *kcore_filename = NULL;
@@ -302,6 +326,8 @@ int cmd_buildid_cache(int argc, const char **argv,
 		   "file", "kcore file to add"),
 	OPT_STRING('r', "remove", &remove_name_list_str, "file list",
 		    "file(s) to remove"),
+	OPT_STRING('p', "purge", &purge_name_list_str, "path list",
+		    "path(s) to remove (remove old caches too)"),
 	OPT_STRING('M', "missing", &missing_filename, "file",
 		   "to find missing build ids in the cache"),
 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
@@ -368,6 +394,24 @@ int cmd_buildid_cache(int argc, const char **argv,
 		}
 	}
 
+	if (purge_name_list_str) {
+		list = strlist__new(true, purge_name_list_str);
+		if (list) {
+			strlist__for_each(pos, list)
+				if (build_id_cache__purge_path(pos->s)) {
+					if (errno == ENOENT) {
+						pr_debug("%s wasn't in the cache\n",
+							 pos->s);
+						continue;
+					}
+					pr_warning("Couldn't remove %s: %s\n",
+						   pos->s, strerror_r(errno, sbuf, sizeof(sbuf)));
+				}
+
+			strlist__delete(list);
+		}
+	}
+
 	if (missing_filename)
 		ret = build_id_cache__fprintf_missing(session, stdout);
 
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 0bc33be..5a9a216 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -281,35 +281,86 @@ void disable_buildid_cache(void)
 	no_buildid_cache = true;
 }
 
+static char *build_id_cache__dirname_from_path(const char *name,
+					       bool is_kallsyms, bool is_vdso)
+{
+	char *realname = (char *)name, *filename;
+	bool slash = is_kallsyms || is_vdso;
+
+	if (!slash) {
+		realname = realpath(name, NULL);
+		if (!realname)
+			return NULL;
+	}
+
+	if (asprintf(&filename, "%s%s%s", buildid_dir, slash ? "/" : "",
+		     is_vdso ? DSO__NAME_VDSO : realname) < 0)
+		filename = NULL;
+
+	if (!slash)
+		free(realname);
+
+	return filename;
+}
+
+struct strlist *build_id_cache__list_build_ids(const char *pathname)
+{
+	struct strlist *list;
+	char *dirname;
+	DIR *dir;
+	struct dirent *d;
+
+	list = strlist__new(true, NULL);
+	dirname = build_id_cache__dirname_from_path(pathname, false, false);
+	if (!list || !dirname)
+		goto error_free;
+
+	/* List up all dirents */
+	dir = opendir(dirname);
+	if (!dir)
+		goto error_free;
+	while ((d = readdir(dir)) != NULL) {
+		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+			continue;
+		strlist__add(list, d->d_name);
+	}
+	closedir(dir);
+
+	free(dirname);
+	return list;
+
+error_free:
+	free(dirname);
+	if (list)
+		strlist__delete(list);
+	return NULL;
+}
+
 int build_id_cache__add_s(const char *sbuild_id, const char *name,
 			  bool is_kallsyms, bool is_vdso)
 {
 	const size_t size = PATH_MAX;
-	char *realname, *filename = zalloc(size),
+	char *realname = NULL, *filename = NULL, *dirname = NULL,
 	     *linkname = zalloc(size), *targetname, *tmp;
-	int len, err = -1;
-	bool slash = is_kallsyms || is_vdso;
+	int err = -1;
 
-	if (is_kallsyms) {
-		if (symbol_conf.kptr_restrict) {
-			pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n");
-			err = 0;
-			goto out_free;
-		}
-		realname = (char *) name;
-	} else
+	if (!is_kallsyms) {
 		realname = realpath(name, NULL);
+		if (!realname)
+			goto out_free;
+	}
 
-	if (realname == NULL || filename == NULL || linkname == NULL)
+	dirname = build_id_cache__dirname_from_path(name, is_kallsyms, is_vdso);
+	if (!dirname)
 		goto out_free;
 
-	len = scnprintf(filename, size, "%s%s%s",
-		       buildid_dir, slash ? "/" : "",
-		       is_vdso ? DSO__NAME_VDSO : realname);
-	if (mkdir_p(filename, 0755))
+	if (mkdir_p(dirname, 0755))
 		goto out_free;
 
-	snprintf(filename + len, size - len, "/%s", sbuild_id);
+	if (asprintf(&filename, "%s/%s", dirname, sbuild_id) < 0) {
+		filename = NULL;
+		goto out_free;
+	}
 
 	if (access(filename, F_OK)) {
 		if (is_kallsyms) {
@@ -337,6 +388,7 @@ out_free:
 	if (!is_kallsyms)
 		free(realname);
 	free(filename);
+	free(dirname);
 	free(linkname);
 	return err;
 }
diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 2a09498..cbcadea 100644
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -22,6 +22,7 @@ bool perf_session__read_build_ids(struct perf_session *session, bool with_hits);
 int perf_session__write_buildid_table(struct perf_session *session, int fd);
 int perf_session__cache_build_ids(struct perf_session *session);
 
+struct strlist *build_id_cache__list_build_ids(const char *pathname);
 bool build_id_cache__cached(const char *sbuild_id);
 int build_id_cache__add_s(const char *sbuild_id,
 			  const char *name, bool is_kallsyms, bool is_vdso);

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