perf help: Make check_emacsclient_version to check strbuf APIs

Make check_emacsclient_version() to check the return value of strbuf
APIs so that it can handle errors in strbuf.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160510054716.6158.11755.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index bc1de9b8fd67..f9830c902b78 100644
--- a/tools/perf/builtin-help.c
+++ b/tools/perf/builtin-help.c
@@ -61,6 +61,7 @@ static int check_emacsclient_version(void)
         struct child_process ec_process;
         const char *argv_ec[] = { "emacsclient", "--version", NULL };
         int version;
+        int ret = -1;
 
         /* emacsclient prints its version number on stderr */
         memset(&ec_process, 0, sizeof(ec_process));
@@ -71,7 +72,10 @@ static int check_emacsclient_version(void)
                 fprintf(stderr, "Failed to start emacsclient.\n");
                 return -1;
         }
-        strbuf_read(&buffer, ec_process.err, 20);
+        if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
+                fprintf(stderr, "Failed to read emacsclient version\n");
+                goto out;
+        }
         close(ec_process.err);
 
         /*
@@ -82,8 +86,7 @@ static int check_emacsclient_version(void)
 
         if (prefixcmp(buffer.buf, "emacsclient")) {
                 fprintf(stderr, "Failed to parse emacsclient version.\n");
-                strbuf_release(&buffer);
-                return -1;
+                goto out;
         }
 
         version = atoi(buffer.buf + strlen("emacsclient"));
@@ -92,12 +95,11 @@ static int check_emacsclient_version(void)
                 fprintf(stderr,
                         "emacsclient version '%d' too old (< 22).\n",
                         version);
-                strbuf_release(&buffer);
-                return -1;
-        }
-
+        } else
+                ret = 0;
+out:
         strbuf_release(&buffer);
-        return 0;
+        return ret;
 }
 
 static void exec_woman_emacs(const char *path, const char *page)