[PATCH v3] perf probe: Find compilation directory path for lazy matching

From: Naohiro Aota
Date: Fri Mar 13 2015 - 01:20:32 EST


If we use lazy matching, it failed to open a souce file if perf command
is invoked outside of compilation directory:

$ perf probe -a '__schedule;clear_*'
Failed to open kernel/sched/core.c: No such file or directory
Error: Failed to add events. (-2)

OTOH, other commands like "probe -L" can solve the souce directory by
themselves. Let's make it possible for lazy matching too!

Signed-off-by: Naohiro Aota <naota@xxxxxxxxx>
---
tools/perf/util/probe-event.c | 59 -----------------------------------
tools/perf/util/probe-finder.c | 71 +++++++++++++++++++++++++++++++++++++++++-
tools/perf/util/probe-finder.h | 4 +++
3 files changed, 74 insertions(+), 60 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index f272a71..32a429b 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -648,65 +648,6 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
return ntevs;
}

-/*
- * Find a src file from a DWARF tag path. Prepend optional source path prefix
- * and chop off leading directories that do not exist. Result is passed back as
- * a newly allocated path on success.
- * Return 0 if file was found and readable, -errno otherwise.
- */
-static int get_real_path(const char *raw_path, const char *comp_dir,
- char **new_path)
-{
- const char *prefix = symbol_conf.source_prefix;
-
- if (!prefix) {
- if (raw_path[0] != '/' && comp_dir)
- /* If not an absolute path, try to use comp_dir */
- prefix = comp_dir;
- else {
- if (access(raw_path, R_OK) == 0) {
- *new_path = strdup(raw_path);
- return *new_path ? 0 : -ENOMEM;
- } else
- return -errno;
- }
- }
-
- *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
- if (!*new_path)
- return -ENOMEM;
-
- for (;;) {
- sprintf(*new_path, "%s/%s", prefix, raw_path);
-
- if (access(*new_path, R_OK) == 0)
- return 0;
-
- if (!symbol_conf.source_prefix) {
- /* In case of searching comp_dir, don't retry */
- zfree(new_path);
- return -errno;
- }
-
- switch (errno) {
- case ENAMETOOLONG:
- case ENOENT:
- case EROFS:
- case EFAULT:
- raw_path = strchr(++raw_path, '/');
- if (!raw_path) {
- zfree(new_path);
- return -ENOENT;
- }
- continue;
-
- default:
- zfree(new_path);
- return -errno;
- }
- }
-}
-
#define LINEBUF_SIZE 256
#define NR_ADDITIONAL_LINES 2

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 46f009a..0fd2df4 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -849,11 +849,22 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
int ret = 0;
+ char *fpath;

if (intlist__empty(pf->lcache)) {
+ const char *comp_dir;
+
+ comp_dir = cu_get_comp_dir(&pf->cu_die);
+ ret = get_real_path(pf->fname, comp_dir, &fpath);
+ if (ret < 0) {
+ pr_warning("Failed to find source file path.\n");
+ return ret;
+ }
+
/* Matching lazy line pattern */
- ret = find_lazy_match_lines(pf->lcache, pf->fname,
+ ret = find_lazy_match_lines(pf->lcache, fpath,
pf->pev->point.lazy_line);
+ free(fpath);
if (ret <= 0)
return ret;
}
@@ -1616,3 +1627,61 @@ found:
return (ret < 0) ? ret : lf.found;
}

+/*
+ * Find a src file from a DWARF tag path. Prepend optional source path prefix
+ * and chop off leading directories that do not exist. Result is passed back as
+ * a newly allocated path on success.
+ * Return 0 if file was found and readable, -errno otherwise.
+ */
+int get_real_path(const char *raw_path, const char *comp_dir,
+ char **new_path)
+{
+ const char *prefix = symbol_conf.source_prefix;
+
+ if (!prefix) {
+ if (raw_path[0] != '/' && comp_dir)
+ /* If not an absolute path, try to use comp_dir */
+ prefix = comp_dir;
+ else {
+ if (access(raw_path, R_OK) == 0) {
+ *new_path = strdup(raw_path);
+ return *new_path ? 0 : -ENOMEM;
+ } else
+ return -errno;
+ }
+ }
+
+ *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
+ if (!*new_path)
+ return -ENOMEM;
+
+ for (;;) {
+ sprintf(*new_path, "%s/%s", prefix, raw_path);
+
+ if (access(*new_path, R_OK) == 0)
+ return 0;
+
+ if (!symbol_conf.source_prefix) {
+ /* In case of searching comp_dir, don't retry */
+ zfree(new_path);
+ return -errno;
+ }
+
+ switch (errno) {
+ case ENAMETOOLONG:
+ case ENOENT:
+ case EROFS:
+ case EFAULT:
+ raw_path = strchr(++raw_path, '/');
+ if (!raw_path) {
+ zfree(new_path);
+ return -ENOENT;
+ }
+ continue;
+
+ default:
+ zfree(new_path);
+ return -errno;
+ }
+ }
+}
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 92590b2..ebf8c8c 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -55,6 +55,10 @@ extern int debuginfo__find_available_vars_at(struct debuginfo *dbg,
struct variable_list **vls,
int max_points, bool externs);

+/* Find a src file from a DWARF tag path */
+int get_real_path(const char *raw_path, const char *comp_dir,
+ char **new_path);
+
struct probe_finder {
struct perf_probe_event *pev; /* Target probe event */

--
2.3.1

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