perf probe: Don't always consider EOF as an error when listing source code

When listing a whole file or a function which is located at the end,
perf-probe -L output wrongly: "Source file is shorter than expected.".

This is because show_one_line() always consider EOF as an error.

This patch fixes this by not considering EOF as an error when dumping
the trailing lines. Otherwise it's still an error and perf-probe still
outputs its warning.

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1292854685-8230-6-git-send-email-fbuihuu@gmail.com>
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 26 insertions, 12 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 3ba9c5393775..80cc0bc284fd 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -287,7 +287,7 @@ static int get_real_path(const char *raw_path, const char *comp_dir,
 #define LINEBUF_SIZE 256
 #define NR_ADDITIONAL_LINES 2
 
-static int show_one_line(FILE *fp, int l, bool skip, bool show_num)
+static int __show_one_line(FILE *fp, int l, bool skip, bool show_num)
 {
         char buf[LINEBUF_SIZE];
         const char *color = show_num ? "" : PERF_COLOR_BLUE;
@@ -306,16 +306,30 @@ static int show_one_line(FILE *fp, int l, bool skip, bool show_num)
 
         } while (strchr(buf, '\n') == NULL);
 
-        return 0;
+        return 1;
 error:
-        if (feof(fp))
+        if (ferror(fp)) {
                 pr_warning("Source file is shorter than expected.\n");
-        else
-                pr_warning("File read error: %s\n", strerror(errno));
+                return -1;
+        }
+        return 0;
+}
 
-        return -1;
+static int _show_one_line(FILE *fp, int l, bool skip, bool show_num)
+{
+        int rv = __show_one_line(fp, l, skip, show_num);
+        if (rv == 0) {
+                pr_warning("Source file is shorter than expected.\n");
+                rv = -1;
+        }
+        return rv;
 }
 
+#define show_one_line_with_num(f,l)     _show_one_line(f,l,false,true)
+#define show_one_line(f,l)              _show_one_line(f,l,false,false)
+#define skip_one_line(f,l)              _show_one_line(f,l,true,false)
+#define show_one_line_or_eof(f,l)       __show_one_line(f,l,false,false)
+
 /*
  * Show line-range always requires debuginfo to find source file and
  * line number.
@@ -374,27 +388,27 @@ int show_line_range(struct line_range *lr, const char *module)
         }
         /* Skip to starting line number */
         while (l < lr->start) {
-                ret = show_one_line(fp, l++, true, false);
+                ret = skip_one_line(fp, l++);
                 if (ret < 0)
                         goto end;
         }
 
         list_for_each_entry(ln, &lr->line_list, list) {
                 for (; ln->line > l; l++) {
-                        ret = show_one_line(fp, l - lr->offset, false, false);
+                        ret = show_one_line(fp, l - lr->offset);
                         if (ret < 0)
                                 goto end;
                 }
-                ret = show_one_line(fp, l++ - lr->offset, false, true);
+                ret = show_one_line_with_num(fp, l++ - lr->offset);
                 if (ret < 0)
                         goto end;
         }
 
         if (lr->end == INT_MAX)
                 lr->end = l + NR_ADDITIONAL_LINES;
-        while (l <= lr->end && !feof(fp)) {
-                ret = show_one_line(fp, l++ - lr->offset, false, false);
-                if (ret < 0)
+        while (l <= lr->end) {
+                ret = show_one_line_or_eof(fp, l++ - lr->offset);
+                if (ret <= 0)
                         break;
         }
 end: