1 files changed, 129 insertions, 0 deletions
diff --git a/cmd/service/help.c b/cmd/service/help.c
new file mode 100644
index 0000000..4fa9951
--- /dev/null
+++ b/cmd/service/help.c
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * Copyright (C) 2018 - David Oberhollenzer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include "servicecmd.h"
+
+extern char *__progname;
+
+static void pretty_print(const char *str, int padd, int len)
+{
+	int i, brk;
+next:
+	while (isspace(*str) && *str != '\n')
+		++str;
+
+	if (!(*str))
+		return;
+
+	if (*str == '\n') {
+		fputc('\n', stdout);
+		++str;
+		len = padd;
+		goto next;
+	}
+
+	for (i = 0, brk = 0; str[i]; ++i) {
+		if (str[i] == '<' || str[i] == '[')
+			++brk;
+		if (str[i] == '>' || str[i] == ']')
+			--brk;
+		if (!brk && isspace(str[i]))
+			break;
+	}
+
+	if ((len + i) < 80) {
+		fwrite(str, 1, i, stdout);
+		str += i;
+		len += i;
+
+		if ((len + 1) < 80) {
+			fputc(' ', stdout);
+			++len;
+			goto next;
+		}
+	}
+
+	printf("\n%*s", padd, "");
+	len = padd;
+	goto next;
+}
+
+static void print_cmd_usage(const char *cmd, const char *usage)
+{
+	int padd;
+
+	padd = printf("Usage: %s %s ", __progname, cmd);
+
+	if ((strlen(usage) + padd) < 80) {
+		fputs(usage, stdout);
+		return;
+	}
+
+	pretty_print(usage, padd, padd);
+}
+
+static int cmd_help(int argc, char **argv)
+{
+	const char *help;
+	command_t *cmd;
+
+	if (argc < 2)
+		usage(EXIT_SUCCESS);
+
+	if (argc > 2) {
+		fprintf(stderr, "Too many arguments\n\n"
+				"Usage: %s help <command>", __progname);
+		return EXIT_FAILURE;
+	}
+
+	for (cmd = commands; cmd != NULL; cmd = cmd->next) {
+		if (strcmp(cmd->cmd, argv[1]) != 0)
+			continue;
+
+		print_cmd_usage(cmd->cmd, cmd->usage);
+		fputs("\n\n", stdout);
+
+		help = cmd->l_desc ? cmd->l_desc : cmd->s_desc;
+
+		if (islower(*help)) {
+			fputc(toupper(*(help++)), stdout);
+			pretty_print(help, 0, 1);
+		} else {
+			pretty_print(help, 0, 0);
+		}
+
+		fputc('\n', stdout);
+		return EXIT_SUCCESS;
+	}
+
+	fprintf(stderr, "Unknown command '%s'\n\n"
+			"Try `%s help' for a list of available commands\n",
+			argv[1], __progname);
+	return EXIT_FAILURE;
+}
+
+static command_t help = {
+	.cmd = "help",
+	.usage = "<command>",
+	.s_desc = "print a help text for a command",
+	.l_desc = "Print a help text for a specified command. If no command "
+		"is specified, print a generic help text and a list of "
+		"available commands.",
+	.run_cmd = cmd_help,
+};
+
+REGISTER_COMMAND(help)