libbpf-tools/trace_helpers: Add a utility to split and convert string

Add a utility API to split and convert strings for argument parsing.

Also, apply the API usage to offcputime and profile to remove duplicates.

libbpf-tools/offcputime.c

@@ -80,27 +80,6 @@ static const struct argp_option opts[] = {
 	{},
 };
 
-static int split_pidstr(char *s, char* delim, int max_split, pid_t *pids)
-{
-	char *pid;
-	int nr = 0;
-
-	errno = 0;
-	pid = strtok(s, delim);
-	while (pid) {
-		if (nr >= max_split)
-			return -ENOBUFS;
-
-		pids[nr++] = strtol(pid, NULL, 10);
-		if (errno)
-			return -errno;
-
-		pid = strtok(NULL, delim);
-	}
-
-	return 0;
-}
-
 static error_t parse_arg(int key, char *arg, struct argp_state *state)
 {
 	static int pos_args;
@@ -114,7 +93,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 		env.verbose = true;
 		break;
 	case 'p':
-		ret = split_pidstr(strdup(arg), ",", MAX_PID_NR, env.pids);
+		ret = split_convert(strdup(arg), ",", env.pids, sizeof(env.pids),
+				    sizeof(pid_t), str_to_int);
 		if (ret) {
 			if (ret == -ENOBUFS)
 				fprintf(stderr, "the number of pid is too big, please "
@@ -126,7 +106,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 		}
 		break;
 	case 't':
-		ret = split_pidstr(strdup(arg), ",", MAX_TID_NR, env.tids);
+		ret = split_convert(strdup(arg), ",", env.tids, sizeof(env.tids),
+				    sizeof(pid_t), str_to_int);
 		if (ret) {
 			if (ret == -ENOBUFS)
 				fprintf(stderr, "the number of tid is too big, please "

libbpf-tools/profile.c

@@ -132,27 +132,6 @@ struct syms_cache *syms_cache;
 struct syms *syms;
 static char syminfo[SYM_INFO_LEN];
 
-static int split_pidstr(char *s, char* sep, int max_split, pid_t *pids)
-{
-	char *pid;
-	int nr = 0;
-
-	errno = 0;
-	pid = strtok(s, sep);
-	while (pid) {
-		if (nr >= max_split)
-			return -ENOBUFS;
-
-		pids[nr++] = strtol(pid, NULL, 10);
-		if (errno)
-			return -errno;
-
-		pid = strtok(NULL, ",");
-	}
-
-	return 0;
-}
-
 static error_t parse_arg(int key, char *arg, struct argp_state *state)
 {
 	static int pos_args;
@@ -166,7 +145,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 		env.verbose = true;
 		break;
 	case 'p':
-		ret = split_pidstr(strdup(arg), ",", MAX_PID_NR, env.pids);
+		ret = split_convert(strdup(arg), ",", env.pids, sizeof(env.pids),
+				    sizeof(pid_t), str_to_int);
 		if (ret) {
 			if (ret == -ENOBUFS)
 				fprintf(stderr, "the number of pid is too big, please "
@@ -178,7 +158,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 		}
 		break;
 	case 'L':
-		ret = split_pidstr(strdup(arg), ",", MAX_TID_NR, env.tids);
+		ret = split_convert(strdup(arg), ",", env.tids, sizeof(env.tids),
+				    sizeof(pid_t), str_to_int);
 		if (ret) {
 			if (ret == -ENOBUFS)
 				fprintf(stderr, "the number of tid is too big, please "

libbpf-tools/trace_helpers.c

@@ -1247,3 +1247,42 @@ bool probe_ringbuf()
 	close(map_fd);
 	return true;
 }
+
+int split_convert(char *s, const char* delim, void *elems, size_t elems_size,
+		  size_t elem_size, convert_fn_t convert)
+{
+	char *token;
+	int ret;
+	char *pos = (char *)elems;
+
+	if (!s || !delim || !elems)
+		return -EINVAL;
+
+	errno = 0;
+	token = strtok(s, delim);
+	while (token) {
+		if (pos >= (char*)elems + elems_size)
+			return -ENOBUFS;
+
+		ret = convert(token, pos);
+		if (ret)
+			return -ret;
+
+		pos += elem_size;
+		token = strtok(NULL, delim);
+	}
+
+	return 0;
+}
+
+int str_to_int(const char *src, void *dest)
+{
+	*(int*)dest = strtol(src, NULL, 10);
+	return errno;
+}
+
+int str_to_long(const char *src, void *dest)
+{
+	*(long*)dest = strtol(src, NULL, 10);
+	return errno;
+}

libbpf-tools/trace_helpers.h

@@ -108,4 +108,16 @@ bool module_btf_exists(const char *mod);
 bool probe_tp_btf(const char *name);
 bool probe_ringbuf();
 
+typedef int (*convert_fn_t)(const char *src, void *dest);
+int split_convert(char *s, const char* delim, void *elems, size_t elems_size,
+		  size_t elem_size, convert_fn_t convert);
+/*
+ * Implementations of convert_fn_t.
+ * This can be replaced with a user-defined callback function.
+ */
+/* converts a string to an integer */
+int str_to_int(const char *src, void *dest);
+/* converts a string to a long integer */
+int str_to_long(const char *src, void *dest);
+
 #endif /* __TRACE_HELPERS_H */