[perf/core PATCH v2 2/4] perf buildid-cache: Consolidate .build-id cache path generators

Masami Hiramatsu
2015-02-10T09:19:43Z

Consolidate .build-id cache path generating routines to
build_id__filename() function. Other functions must use
it to get the buildid cache path (link path) from build-id.
This can reduce the risk of partial-update.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
tools/perf/util/build-id.c | 58 +++++++++++++++++++++++++++++++-------------
1 file changed, 41 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 9f764f6..adbc360 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -93,6 +93,35 @@ int build_id__sprintf(const u8 *build_id, int len, char *bf)
return raw - build_id;
}

+/* asnprintf consolidates asprintf and snprintf */
+static int asnprintf(char **strp, size_t size, const char *fmt, ...)
+{
+ va_list ap;
+ int ret;
+
+ if (!strp)
+ return -EINVAL;
+
+ va_start(ap, fmt);
+ if (*strp)
+ ret = vsnprintf(*strp, size, fmt, ap);
+ else
+ ret = vasprintf(strp, fmt, ap);
+ va_end(ap);
+
+ return ret;
+}
+
+static char *build_id__filename(const char *sbuild_id, char *bf, size_t size)
+{
+ char *tmp = bf;
+ int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
+ sbuild_id, sbuild_id + 2);
+ if (ret < 0 || (tmp && size < (unsigned int)ret))
+ return NULL;
+ return bf;
+}
+
char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
{
char build_id_hex[BUILD_ID_SIZE * 2 + 1];
@@ -101,14 +130,7 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
return NULL;

build_id__sprintf(dso->build_id, sizeof(dso->build_id), build_id_hex);
- if (bf == NULL) {
- if (asprintf(&bf, "%s/.build-id/%.2s/%s", buildid_dir,
- build_id_hex, build_id_hex + 2) < 0)
- return NULL;
- } else
- snprintf(bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
- build_id_hex, build_id_hex + 2);
- return bf;
+ return build_id__filename(build_id_hex, bf, size);
}

#define dsos__for_each_with_build_id(pos, head) \
@@ -264,7 +286,7 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
{
const size_t size = PATH_MAX;
char *realname, *filename = zalloc(size),
- *linkname = zalloc(size), *targetname;
+ *linkname = zalloc(size), *targetname, *tmp;
int len, err = -1;
bool slash = is_kallsyms || is_vdso;

@@ -297,13 +319,15 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
goto out_free;
}

- len = scnprintf(linkname, size, "%s/.build-id/%.2s",
- buildid_dir, sbuild_id);
+ if (!build_id__filename(sbuild_id, linkname, size))
+ goto out_free;
+ tmp = strrchr(linkname, '/');
+ *tmp = '\0';

if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
goto out_free;

- snprintf(linkname + len, size - len, "/%s", sbuild_id + 2);
+ *tmp = '/';
targetname = filename + strlen(buildid_dir) - 5;
memcpy(targetname, "../..", 5);

@@ -332,14 +356,14 @@ int build_id_cache__remove_s(const char *sbuild_id)
{
const size_t size = PATH_MAX;
char *filename = zalloc(size),
- *linkname = zalloc(size);
+ *linkname = zalloc(size), *tmp;
int err = -1;

if (filename == NULL || linkname == NULL)
goto out_free;

- snprintf(linkname, size, "%s/.build-id/%.2s/%s",
- buildid_dir, sbuild_id, sbuild_id + 2);
+ if (!build_id__filename(sbuild_id, linkname, size))
+ goto out_free;

if (access(linkname, F_OK))
goto out_free;
@@ -353,8 +377,8 @@ int build_id_cache__remove_s(const char *sbuild_id)
/*
* Since the link is relative, we must make it absolute:
*/
- snprintf(linkname, size, "%s/.build-id/%.2s/%s",
- buildid_dir, sbuild_id, filename);
+ tmp = strrchr(linkname, '/') + 1;
+ snprintf(tmp, size - (tmp - linkname), "%s", filename);

if (unlink(linkname))
goto out_free;