perf probe: Handle gracefully some stupid and buggy line syntaxes

Currently perf probe doesn't handle those incorrect syntaxes:

   $ perf probe -L sched.c:++13
   $ perf probe -L sched.c:-+13
   $ perf probe -L sched.c:10000000000000000000000000000+13

This patches rewrites parse_line_range_desc() to handle them.

As a bonus, it reports more useful error messages instead of: "Tailing
with invalid character...".

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1292854685-8230-7-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, 60 insertions, 32 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 80cc0bc284fd..099336ed34b4 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -529,6 +529,19 @@ int show_available_vars(struct perf_probe_event *pevs __unused,
 }
 #endif
 
+static int parse_line_num(char **ptr, int *val, const char *what)
+{
+        const char *start = *ptr;
+
+        errno = 0;
+        *val = strtol(*ptr, ptr, 0);
+        if (errno || *ptr == start) {
+                semantic_error("'%s' is not a valid number.\n", what);
+                return -EINVAL;
+        }
+        return 0;
+}
+
 /*
  * Stuff 'lr' according to the line range described by 'arg'.
  * The line range syntax is described by:
@@ -538,50 +551,65 @@ int show_available_vars(struct perf_probe_event *pevs __unused,
  */
 int parse_line_range_desc(const char *arg, struct line_range *lr)
 {
-        const char *ptr;
-        char *tmp;
+        char *range, *name = strdup(arg);
+        int err;
+
+        if (!name)
+                return -ENOMEM;
+
+        lr->start = 0;
+        lr->end = INT_MAX;
+
+        range = strchr(name, ':');
+        if (range) {
+                *range++ = '\0';
+
+                err = parse_line_num(&range, &lr->start, "start line");
+                if (err)
+                        goto err;
+
+                if (*range == '+' || *range == '-') {
+                        const char c = *range++;
+
+                        err = parse_line_num(&range, &lr->end, "end line");
+                        if (err)
+                                goto err;
+
+                        if (c == '+') {
+                                lr->end += lr->start;
+                                /*
+                                 * Adjust the number of lines here.
+                                 * If the number of lines == 1, the
+                                 * the end of line should be equal to
+                                 * the start of line.
+                                 */
+                                lr->end--;
+                        }
+                }
 
-        ptr = strchr(arg, ':');
-        if (ptr) {
-                lr->start = (int)strtoul(ptr + 1, &tmp, 0);
-                if (*tmp == '+') {
-                        lr->end = lr->start + (int)strtoul(tmp + 1, &tmp, 0);
-                        lr->end--;      /*
-                                         * Adjust the number of lines here.
-                                         * If the number of lines == 1, the
-                                         * the end of line should be equal to
-                                         * the start of line.
-                                         */
-                } else if (*tmp == '-')
-                        lr->end = (int)strtoul(tmp + 1, &tmp, 0);
-                else
-                        lr->end = INT_MAX;
                 pr_debug("Line range is %d to %d\n", lr->start, lr->end);
+
+                err = -EINVAL;
                 if (lr->start > lr->end) {
                         semantic_error("Start line must be smaller"
                                        " than end line.\n");
-                        return -EINVAL;
+                        goto err;
                 }
-                if (*tmp != '\0') {
-                        semantic_error("Tailing with invalid character '%d'.\n",
-                                       *tmp);
-                        return -EINVAL;
+                if (*range != '\0') {
+                        semantic_error("Tailing with invalid str '%s'.\n", range);
+                        goto err;
                 }
-                tmp = strndup(arg, (ptr - arg));
-        } else {
-                tmp = strdup(arg);
-                lr->end = INT_MAX;
         }
 
-        if (tmp == NULL)
-                return -ENOMEM;
-
-        if (strchr(tmp, '.'))
-                lr->file = tmp;
+        if (strchr(name, '.'))
+                lr->file = name;
         else
-                lr->function = tmp;
+                lr->function = name;
 
         return 0;
+err:
+        free(name);
+        return err;
 }
 
 /* Check the name is good for event/group */