[PATCH v4 3/6] trace-cmd library: Fix possible memory leak in read_event_files()

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

Some error paths in read_event_files() may lead to a memory leak.
Improved the error handling of this internal function to avoid it.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-input.c | 39 ++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index aaafe3a4..0a42ca4e 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -644,7 +644,7 @@ static int read_ftrace_files(struct tracecmd_input *handle, const char *regex)
 static int read_event_files(struct tracecmd_input *handle, const char *regex)
 {
 	unsigned long long size;
-	char *system;
+	char *system = NULL;
 	regex_t spreg;
 	regex_t epreg;
 	regex_t *sreg = NULL;
@@ -669,13 +669,16 @@ static int read_event_files(struct tracecmd_input *handle, const char *regex)
 			return -1;
 	}
 
-	if (read4(handle, &systems) < 0)
-		return -1;
+	ret = read4(handle, &systems);
+	if (ret < 0)
+		goto out;
 
 	for (i = 0; i < systems; i++) {
 		system = read_string(handle);
-		if (!system)
-			return -1;
+		if (!system) {
+			ret = -1;
+			goto out;
+		}
 
 		sys_printed = 0;
 		print_all = 0;
@@ -702,39 +705,35 @@ static int read_event_files(struct tracecmd_input *handle, const char *regex)
 			}
 		}
 
-		if (read4(handle, &count) < 0)
-			goto failed;
+		ret = read4(handle, &count);
+		if (ret < 0)
+			goto out;
 
 		for (x=0; x < count; x++) {
-			if (read8(handle, &size) < 0)
-				goto failed;
+			ret = read8(handle, &size);
+			if (ret < 0)
+				goto out;
 
 			ret = read_event_file(handle, system, size,
 					      print_all, &sys_printed,
 					      reg);
 			if (ret < 0)
-				goto failed;
+				goto out;
 		}
 		free(system);
 	}
-
-	if (sreg) {
-		regfree(sreg);
-		regfree(ereg);
-	}
+	system = NULL;
 
 	handle->file_state = TRACECMD_FILE_ALL_EVENTS;
-
-	return 0;
-
- failed:
+	ret = 0;
+ out:
 	if (sreg) {
 		regfree(sreg);
 		regfree(ereg);
 	}
 
 	free(system);
-	return -1;
+	return ret;
 }
 
 static int read_proc_kallsyms(struct tracecmd_input *handle)
-- 
2.31.1