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 (file)
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -195,6 +195,55 @@ static int try_to_find_kprobe_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, 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 @@ int show_line_range(struct line_range *lr)
        struct line_node *ln;
        FILE *fp;
        int fd, ret;
+       char *tmp;
 
        /* Search a line range */
        ret = init_vmlinux();
@@ -266,6 +316,15 @@ int show_line_range(struct line_range *lr)
                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)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 3e64e1f..a934a36 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -58,55 +58,6 @@ static int strtailcmp(const char *s1, const char *s2)
        return 0;
 }
 
-/*
- * 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;
-               }
-       }
-}
-
 /* Line number list operations */
 
 /* Add a line to line number list */
@@ -1256,13 +1207,11 @@ end:
 static int line_range_add_line(const char *src, unsigned int lineno,
                               struct line_range *lr)
 {
-       int ret;
-
-       /* Copy real path */
+       /* Copy source path */
        if (!lr->path) {
-               ret = get_real_path(src, &lr->path);
-               if (ret != 0)
-                       return ret;
+               lr->path = strdup(src);
+               if (lr->path == NULL)
+                       return -ENOMEM;
        }
        return line_list__add_line(&lr->line_list, lineno);
 }
@@ -1460,7 +1409,7 @@ int find_line_range(int fd, struct line_range *lr)
                }
                off = noff;
        }
-       pr_debug("path: %lx\n", (unsigned long)lr->path);
+       pr_debug("path: %s\n", lr->path);
        dwarf_end(dbg);
 
        return (ret < 0) ? ret : lf.found;