add inittab support

1 files changed, 284 insertions, 0 deletions

diff --git a/inittab.c b/inittab.c
new file mode 100644
index 0000000..32be11f
--- /dev/null
+++ b/inittab.c
@@ -0,0 +1,284 @@
+/*
+ * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <regex.h>
+
+#include <libubox/utils.h>
+#include <libubox/list.h>
+
+#include "procd.h"
+
+#define TAG_ID		0
+#define TAG_RUNLVL	1
+#define TAG_ACTION	2
+#define TAG_PROCESS	3
+
+#define MAX_ARGS	8
+
+struct init_action;
+const char *console;
+
+struct init_handler {
+	const char *name;
+	void (*cb) (struct init_action *a);
+	int atomic;
+};
+
+struct init_action {
+	struct list_head list;
+
+	char *id;
+	char *argv[MAX_ARGS];
+	char *line;
+
+	struct init_handler *handler;
+	struct uloop_process proc;
+
+	int pending;
+	int respawn;
+	struct uloop_timeout tout;
+};
+
+static const char *tab = "/etc/inittab";
+static char *ask = "/sbin/askfirst";
+
+static struct init_action *pending;
+
+static LIST_HEAD(actions);
+
+static void fork_script(struct init_action *a)
+{
+	a->proc.pid = fork();
+	if (!a->proc.pid) {
+		execvp(a->argv[0], a->argv);
+		ERROR("Failed to execute %s\n", a->argv[0]);
+		exit(-1);
+	}
+
+	if (a->proc.pid > 0) {
+		DEBUG(2, "Launched new %s action, pid=%d\n",
+					a->handler->name,
+					(int) a->proc.pid);
+		uloop_process_add(&a->proc);
+	}
+}
+
+static void child_exit(struct uloop_process *proc, int ret)
+{
+	struct init_action *a = container_of(proc, struct init_action, proc);
+
+	DEBUG(2, "pid:%d\n", proc->pid);
+	if (a->tout.cb) {
+	        uloop_timeout_set(&a->tout, a->respawn);
+	} else {
+		a->pending = 0;
+		pending = NULL;
+		procd_state_next();
+	}
+}
+
+static void respawn(struct uloop_timeout *tout)
+{
+	struct init_action *a = container_of(tout, struct init_action, tout);
+	fork_script(a);
+}
+
+static void runscript(struct init_action *a)
+{
+	a->proc.cb = child_exit;
+	fork_script(a);
+}
+
+static void askfirst(struct init_action *a)
+{
+	struct stat s;
+	int i;
+
+	chdir("/dev");
+	i = stat(a->id, &s);
+	chdir("/");
+	if (i || (console && !strcmp(console, a->id))) {
+		DEBUG(2, "Skipping %s\n", a->id);
+		return;
+	}
+
+	a->tout.cb = respawn;
+	for (i = MAX_ARGS - 2; i >= 2; i--)
+		a->argv[i] = a->argv[i - 2];
+	a->argv[0] = ask;
+	a->argv[1] = a->id;
+	a->respawn = 500;
+
+	a->proc.cb = child_exit;
+	fork_script(a);
+}
+
+static void askconsole(struct init_action *a)
+{
+	struct stat s;
+	char line[256], *tty;
+	int i, r, fd = open("/proc/cmdline", O_RDONLY);
+	regex_t pat_cmdline;
+	regmatch_t matches[2];
+
+	if (!fd)
+		return;
+
+	r = read(fd, line, sizeof(line) - 1);
+	line[r] = '\0';
+	close(fd);
+
+	regcomp(&pat_cmdline, "console=([a-zA-Z0-9]*)", REG_EXTENDED);
+	if (regexec(&pat_cmdline, line, 2, matches, 0))
+		goto err_out;
+	line[matches[1].rm_eo] = '\0';
+	tty = &line[matches[1].rm_so];
+
+	chdir("/dev");
+	i = stat(tty, &s);
+	chdir("/");
+	if (i) {
+		DEBUG(2, "skipping %s\n", tty);
+		goto err_out;
+	}
+	console = strdup(tty);
+
+	a->tout.cb = respawn;
+	for (i = MAX_ARGS - 2; i >= 2; i--)
+		a->argv[i] = a->argv[i - 2];
+	a->argv[0] = ask;
+	a->argv[1] = strdup(tty);
+	a->respawn = 500;
+
+	a->proc.cb = child_exit;
+	fork_script(a);
+err_out:
+	regfree(&pat_cmdline);
+}
+
+static struct init_handler handlers[] = {
+	{
+		.name = "sysinit",
+		.cb = runscript,
+	}, {
+		.name = "shutdown",
+		.cb = runscript,
+	}, {
+		.name = "askfirst",
+		.cb = askfirst,
+		.atomic = 1,
+	}, {
+		.name = "askconsole",
+		.cb = askconsole,
+		.atomic = 1,
+	}
+};
+
+static int add_action(struct init_action *a, const char *name)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(handlers); i++)
+		if (!strcmp(handlers[i].name, name)) {
+			a->handler = &handlers[i];
+			list_add_tail(&a->list, &actions);
+			return 0;
+		}
+	ERROR("Unknown init handler %s\n", name);
+	return -1;
+}
+
+void procd_inittab_run(const char *handler)
+{
+	struct init_action *a;
+
+	list_for_each_entry(a, &actions, list)
+		if (!strcmp(a->handler->name, handler)) {
+			if (a->handler->atomic) {
+				a->handler->cb(a);
+				continue;
+			}
+			if (pending || a->pending)
+				break;
+			a->pending = 1;
+			pending = a;
+			a->handler->cb(a);
+		}
+}
+
+void procd_inittab(void)
+{
+#define LINE_LEN	128
+	FILE *fp = fopen(tab, "r");
+	struct init_action *a;
+	regex_t pat_inittab;
+	regmatch_t matches[5];
+	char *line;
+
+	if (!fp) {
+		ERROR("Failed to open %s\n", tab);
+		return;
+	}
+
+	regcomp(&pat_inittab, "([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9]*):([a-zA-Z0-9/[.-.]. ]*)", REG_EXTENDED);
+	line = malloc(LINE_LEN);
+	a = malloc(sizeof(struct init_action));
+	memset(a, 0, sizeof(struct init_action));
+
+	while (fgets(line, LINE_LEN, fp)) {
+		char *tags[TAG_PROCESS + 1];
+		char *tok;
+		int i;
+
+		if (*line == '#')
+			continue;
+
+		if (regexec(&pat_inittab, line, 5, matches, 0))
+			continue;
+
+		DEBUG(2, "Parsing inittab - %s", line);
+
+		for (i = TAG_ID; i <= TAG_PROCESS; i++) {
+			line[matches[i].rm_eo] = '\0';
+			tags[i] = &line[matches[i + 1].rm_so];
+		};
+
+		tok = strtok(tags[TAG_PROCESS], " ");
+		for (i = 0; i < (MAX_ARGS - i - 1) && tok; i++) {
+			a->argv[i] = tok;
+			tok = strtok(NULL, " ");
+		}
+		a->argv[i] = NULL;
+		a->id = tags[TAG_ID];
+		a->line = line;
+
+		if (add_action(a, tags[TAG_ACTION]))
+			continue;
+		line = malloc(LINE_LEN);
+		a = malloc(sizeof(struct init_action));
+		memset(a, 0, sizeof(struct init_action));
+	}
+
+	fclose(fp);
+	free(line);
+	free(a);
+	regfree(&pat_inittab);
+}