perf probe: Fix error message if get_real_path() failed
Perf probe -L shows incorrect error message (Dwarf error) if it fails to find
source file. This can confuse users.
# ./perf probe -s /nowhere -L vfs_read
Debuginfo analysis failed. (-2)
Error: Failed to show lines. (-2)
With this patch, it shows correct message.
# ./perf probe -s /nowhere -L vfs_read
Failed to find source file. (-2)
Error: Failed to show lines. (-2)
LKML-Reference: <4C36EBDB.4020308@hitachi.com>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 09cf546..8d08e75 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -195,6 +195,55 @@
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, char **new_path)
+{
+ if (!symbol_conf.source_prefix) {
+ if (access(raw_path, R_OK) == 0) {
+ *new_path = strdup(raw_path);
+ return 0;
+ } else
+ return -errno;
+ }
+
+ *new_path = malloc((strlen(symbol_conf.source_prefix) +
+ strlen(raw_path) + 2));
+ if (!*new_path)
+ return -ENOMEM;
+
+ for (;;) {
+ sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,
+ raw_path);
+
+ if (access(*new_path, R_OK) == 0)
+ return 0;
+
+ switch (errno) {
+ case ENAMETOOLONG:
+ case ENOENT:
+ case EROFS:
+ case EFAULT:
+ raw_path = strchr(++raw_path, '/');
+ if (!raw_path) {
+ free(*new_path);
+ *new_path = NULL;
+ return -ENOENT;
+ }
+ continue;
+
+ default:
+ free(*new_path);
+ *new_path = NULL;
+ return -errno;
+ }
+ }
+}
+
#define LINEBUF_SIZE 256
#define NR_ADDITIONAL_LINES 2
@@ -244,6 +293,7 @@
struct line_node *ln;
FILE *fp;
int fd, ret;
+ char *tmp;
/* Search a line range */
ret = init_vmlinux();
@@ -266,6 +316,15 @@
return ret;
}
+ /* Convert source file path */
+ tmp = lr->path;
+ ret = get_real_path(tmp, &lr->path);
+ free(tmp); /* Free old path */
+ if (ret < 0) {
+ pr_warning("Failed to find source file. (%d)\n", ret);
+ return ret;
+ }
+
setup_pager();
if (lr->function)