libbpf-tools/memleak: Fix to handle failure for invalid arguments (iovisor#5147)

Argument parsing errors are not detected for -p, -o, and -T due to the use of
atoi.
So, fixed these to handle invalid arguments by using strtol instead.

Before:
  # ./memleak_new -p haha
    using default object: libc.so.6
    using page size: 4096
    tracing kernel: false
    Tracing outstanding memory allocs...  Hit Ctrl-C to end

  # ./memleak -o 99999999999999999999999999999999999999999999999
    using default object: libc.so.6
    using page size: 4096
    tracing kernel: true
    Tracing outstanding memory allocs...  Hit Ctrl-C to end

After:
  # ./memleak_new -p haha
    error arg:p haha
    Usage: memleak_new [OPTION...]
    Try `memleak_new --help' or `memleak_new --usage' for more information.

  # ./memleak_new -o 99999999999999999999999999999999999999999999999
    error arg:o 99999999999999999999999999999999999999999999999
    Usage: memleak_new [OPTION...]
    Try `memleak_new --help' or `memleak_new --usage' for more information.

  # ./memleak_new -o 9999999999999999
    invalid AGE_MS: 9999999999999999
    Usage: memleak_new [OPTION...]
    Try `memleak_new --help' or `memleak_new --usage' for more information.

Author: ekyooo

libbpf-tools/memleak.c

@@ -35,7 +35,7 @@ static struct env {
 	bool trace_all;
 	bool show_allocs;
 	bool combined_only;
-	int min_age_ns;
+	long min_age_ns;
 	uint64_t sample_rate;
 	int top_stacks;
 	size_t min_size;
@@ -508,10 +508,11 @@ long argp_parse_long(int key, const char *arg, struct argp_state *state)
 error_t argp_parse_arg(int key, char *arg, struct argp_state *state)
 {
 	static int pos_args = 0;
+	long age_ms;
 
 	switch (key) {
 	case 'p':
-		env.pid = atoi(arg);
+		env.pid = argp_parse_long(key, arg, state);
 		break;
 	case 't':
 		env.trace_all = true;
@@ -520,7 +521,12 @@ error_t argp_parse_arg(int key, char *arg, struct argp_state *state)
 		env.show_allocs = true;
 		break;
 	case 'o':
-		env.min_age_ns = 1e6 * atoi(arg);
+		age_ms = argp_parse_long(key, arg, state);
+		if (age_ms > (LONG_MAX / 1e6) || age_ms < (LONG_MIN / 1e6)) {
+			fprintf(stderr, "invalid AGE_MS: %s\n", arg);
+			argp_usage(state);
+		}
+		env.min_age_ns = age_ms * 1e6;
 		break;
 	case 'c':
 		strncpy(env.command, arg, sizeof(env.command) - 1);
@@ -538,7 +544,7 @@ error_t argp_parse_arg(int key, char *arg, struct argp_state *state)
 		strncpy(env.symbols_prefix, arg, sizeof(env.symbols_prefix) - 1);
 		break;
 	case 'T':
-		env.top_stacks = atoi(arg);
+		env.top_stacks = argp_parse_long(key, arg, state);
 		break;
 	case 'z':
 		env.min_size = argp_parse_long(key, arg, state);