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Subject[PATCH perf/core v8 03/16] perf-buildid-cache: Use path/to/bin/buildid/elf instead of path/to/bin/buildid
Date
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Use path/to/bin/buildid/elf instead of path/to/bin/buildid
to store corresponding elf binary.
This also stores vdso in buildid/vdso, kallsyms in buildid/kallsyms.

Note that the existing caches are not updated until user adds
or updates the cache. Anyway, if there is the old style build-id
cache it falls back to use it. (IOW, it is backward compatible)

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v7:
- Move kallsyms buildid related code into build-id.c
(as build_id_cache__kallsyms_path).
Changes in v6:
- Replace local __is_regular_file with is_regular_file in util.c.
(Thank you Namhyung!)
- Fix dso__build_id_is_kmod() to check symlink in buildid cache correctly.
Changes in v5:
- Support old style buildid caches.
---
tools/perf/util/build-id.c | 115 ++++++++++++++++++++++++++++++++++----------
tools/perf/util/build-id.h | 2 +
tools/perf/util/dso.h | 5 ++
tools/perf/util/symbol.c | 5 --
4 files changed, 96 insertions(+), 31 deletions(-)

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 67e5966..67f986c 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -144,7 +144,32 @@ static int asnprintf(char **strp, size_t size, const char *fmt, ...)
return ret;
}

-static char *build_id__filename(const char *sbuild_id, char *bf, size_t size)
+char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
+ size_t size)
+{
+ bool is_alloc = !!bf;
+ bool retry_old = true;
+
+ asnprintf(&bf, size, "%s/%s/%s/kallsyms",
+ buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
+retry:
+ if (!access(bf, F_OK))
+ return bf;
+ if (is_alloc)
+ free(bf);
+ if (retry_old) {
+ /* Try old style kallsyms cache */
+ asnprintf(&bf, size, "%s/%s/%s",
+ buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
+ retry_old = false;
+ goto retry;
+ }
+
+ return NULL;
+}
+
+static char *build_id_cache__linkname(const char *sbuild_id, char *bf,
+ size_t size)
{
char *tmp = bf;
int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
@@ -154,23 +179,52 @@ static char *build_id__filename(const char *sbuild_id, char *bf, size_t size)
return bf;
}

+static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
+{
+ return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
+}
+
char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
{
- char build_id_hex[SBUILD_ID_SIZE];
+ bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
+ bool is_vdso = dso__is_vdso((struct dso *)dso);
+ char sbuild_id[SBUILD_ID_SIZE];
+ char *linkname;
+ bool alloc = (bf == NULL);
+ int ret;

if (!dso->has_build_id)
return NULL;

- build_id__sprintf(dso->build_id, sizeof(dso->build_id), build_id_hex);
- return build_id__filename(build_id_hex, bf, size);
+ build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
+ linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
+ if (!linkname)
+ return NULL;
+
+ /* Check if old style build_id cache */
+ if (is_regular_file(linkname))
+ ret = asnprintf(&bf, size, "%s", linkname);
+ else
+ ret = asnprintf(&bf, size, "%s/%s", linkname,
+ build_id_cache__basename(is_kallsyms, is_vdso));
+ if (ret < 0 || (!alloc && size < (unsigned int)ret))
+ bf = NULL;
+ free(linkname);
+
+ return bf;
}

bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size)
{
- char *id_name, *ch;
+ char *id_name = NULL, *ch;
struct stat sb;
+ char sbuild_id[SBUILD_ID_SIZE];
+
+ if (!dso->has_build_id)
+ goto err;

- id_name = dso__build_id_filename(dso, bf, size);
+ build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
+ id_name = build_id_cache__linkname(sbuild_id, NULL, 0);
if (!id_name)
goto err;
if (access(id_name, F_OK))
@@ -194,18 +248,14 @@ bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size)
if (ch - 3 < bf)
goto err;

+ free(id_name);
return strncmp(".ko", ch - 3, 3) == 0;
err:
- /*
- * If dso__build_id_filename work, get id_name again,
- * because id_name points to bf and is broken.
- */
- if (id_name)
- id_name = dso__build_id_filename(dso, bf, size);
pr_err("Invalid build id: %s\n", id_name ? :
dso->long_name ? :
dso->short_name ? :
"[unknown]");
+ free(id_name);
return false;
}

@@ -341,7 +391,8 @@ void disable_buildid_cache(void)
}

static char *build_id_cache__dirname_from_path(const char *name,
- bool is_kallsyms, bool is_vdso)
+ bool is_kallsyms, bool is_vdso,
+ const char *sbuild_id)
{
char *realname = (char *)name, *filename;
bool slash = is_kallsyms || is_vdso;
@@ -352,8 +403,9 @@ static char *build_id_cache__dirname_from_path(const char *name,
return NULL;
}

- if (asprintf(&filename, "%s%s%s", buildid_dir, slash ? "/" : "",
- is_vdso ? DSO__NAME_VDSO : realname) < 0)
+ if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
+ is_vdso ? DSO__NAME_VDSO : realname,
+ sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
filename = NULL;

if (!slash)
@@ -368,7 +420,8 @@ int build_id_cache__list_build_ids(const char *pathname,
char *dir_name;
int ret = 0;

- dir_name = build_id_cache__dirname_from_path(pathname, false, false);
+ dir_name = build_id_cache__dirname_from_path(pathname, false, false,
+ NULL);
if (!dir_name)
return -ENOMEM;

@@ -385,7 +438,7 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
{
const size_t size = PATH_MAX;
char *realname = NULL, *filename = NULL, *dir_name = NULL,
- *linkname = zalloc(size), *targetname, *tmp;
+ *linkname = zalloc(size), *tmp;
int err = -1;

if (!is_kallsyms) {
@@ -394,14 +447,22 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
goto out_free;
}

- dir_name = build_id_cache__dirname_from_path(name, is_kallsyms, is_vdso);
+ dir_name = build_id_cache__dirname_from_path(name, is_kallsyms,
+ is_vdso, sbuild_id);
if (!dir_name)
goto out_free;

+ /* Remove old style build-id cache */
+ if (is_regular_file(dir_name))
+ if (unlink(dir_name))
+ goto out_free;
+
if (mkdir_p(dir_name, 0755))
goto out_free;

- if (asprintf(&filename, "%s/%s", dir_name, sbuild_id) < 0) {
+ /* Save the allocated buildid dirname */
+ if (asprintf(&filename, "%s/%s", dir_name,
+ build_id_cache__basename(is_kallsyms, is_vdso)) < 0) {
filename = NULL;
goto out_free;
}
@@ -415,7 +476,7 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
goto out_free;
}

- if (!build_id__filename(sbuild_id, linkname, size))
+ if (!build_id_cache__linkname(sbuild_id, linkname, size))
goto out_free;
tmp = strrchr(linkname, '/');
*tmp = '\0';
@@ -424,10 +485,10 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
goto out_free;

*tmp = '/';
- targetname = filename + strlen(buildid_dir) - 5;
- memcpy(targetname, "../..", 5);
+ tmp = dir_name + strlen(buildid_dir) - 5;
+ memcpy(tmp, "../..", 5);

- if (symlink(targetname, linkname) == 0)
+ if (symlink(tmp, linkname) == 0)
err = 0;
out_free:
if (!is_kallsyms)
@@ -452,7 +513,7 @@ static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
bool build_id_cache__cached(const char *sbuild_id)
{
bool ret = false;
- char *filename = build_id__filename(sbuild_id, NULL, 0);
+ char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);

if (filename && !access(filename, F_OK))
ret = true;
@@ -471,7 +532,7 @@ int build_id_cache__remove_s(const char *sbuild_id)
if (filename == NULL || linkname == NULL)
goto out_free;

- if (!build_id__filename(sbuild_id, linkname, size))
+ if (!build_id_cache__linkname(sbuild_id, linkname, size))
goto out_free;

if (access(linkname, F_OK))
@@ -489,7 +550,7 @@ int build_id_cache__remove_s(const char *sbuild_id)
tmp = strrchr(linkname, '/') + 1;
snprintf(tmp, size - (tmp - linkname), "%s", filename);

- if (unlink(linkname))
+ if (rm_rf(linkname))
goto out_free;

err = 0;
@@ -501,7 +562,7 @@ out_free:

static int dso__cache_build_id(struct dso *dso, struct machine *machine)
{
- bool is_kallsyms = dso->kernel && dso->long_name[0] != '/';
+ bool is_kallsyms = dso__is_kallsyms(dso);
bool is_vdso = dso__is_vdso(dso);
const char *name = dso->long_name;
char nm[PATH_MAX];
diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 64af3e2..e5435f4 100644
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -14,6 +14,8 @@ struct dso;
int build_id__sprintf(const u8 *build_id, int len, char *bf);
int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id);
int filename__sprintf_build_id(const char *pathname, char *sbuild_id);
+char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
+ size_t size);

char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size);
bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size);
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 0953280..76d79d0 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -349,6 +349,11 @@ static inline bool dso__is_kcore(struct dso *dso)
dso->binary_type == DSO_BINARY_TYPE__GUEST_KCORE;
}

+static inline bool dso__is_kallsyms(struct dso *dso)
+{
+ return dso->kernel && dso->long_name[0] != '/';
+}
+
void dso__free_a2l(struct dso *dso);

enum dso_type dso__type(struct dso *dso, struct machine *machine);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index abda8ba..9aa73de 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1704,10 +1704,7 @@ proc_kallsyms:
}

/* Finally, find a cache of kallsyms */
- scnprintf(path, sizeof(path), "%s/%s/%s",
- buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
-
- if (access(path, F_OK)) {
+ if (!build_id_cache__kallsyms_path(sbuild_id, path, sizeof(path))) {
pr_err("No kallsyms or vmlinux with build-id %s was found\n",
sbuild_id);
return NULL;
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