Add basic support to specify login TTYs in configuration

This also adds support for monitor /dev for TTYs appering after boot, USB-to-serial converters for example. Some limitations: Baudrate (and other settings) is hardcoded for now, should be read from config file.
2026-10-01 13:33:09 +07:00 · 2013-01-22 21:17:20 +01:00
parent a18c5f3441
commit 5961748b2a
7 changed files with 200 additions and 57 deletions
@@ -38,7 +38,7 @@ EXEC        = finit reboot
 HEADERS     = plugin.h svc.h helpers.h queue.h
 DISTFILES   = LICENSE README ChangeLog finit.conf services
 OBJS        = finit.o conf.o helpers.o sig.o svc.o plugin.o
-OBJS       += strlcpy.o
+OBJS       += strlcpy.o tty.o
 SRCS        = $(OBJS:.o=.c)
 DEPS        = $(addprefix .,$(SRCS:.c=.d))

@@ -31,7 +31,6 @@
 #define MATCH_CMD(l, c, x)					\
 	(!strncmp(l, c, strlen(c)) && (x = (l) + strlen(c)))

-
 static char *build_cmd(char *cmd, char *line, int len)
 {
 	int l;
@@ -135,6 +134,20 @@ void parse_finit_conf(char *file)
 				svc_register(x, NULL);
 				continue;
 			}
+
+			if (MATCH_CMD(line, "console ", x)) {
+				if (console) free(console);
+				console = build_cmd(NULL, x, CMD_SIZE);
+				continue;
+			}
+
+			if (MATCH_CMD(line, "tty ", x)) {
+				char *tty = build_cmd(NULL, x, CMD_SIZE);
+				int baud = 115200; /* TODO: Read from config file. */
+
+				tty_add(tty, baud);
+				continue;
+			}
 		}
 		fclose(fp);
 	}
@@ -35,14 +35,14 @@
 #include "sig.h"
 #include "lite.h"

-int   debug    = 0;
-int   verbose  = 1;
-char *sdown    = NULL;
-char *network  = NULL;
-char *username = NULL;
-char *hostname = NULL;
-char *rcsd     = NULL;
-
+int   debug      = 0;
+int   verbose    = 1;
+char *sdown      = NULL;
+char *network    = NULL;
+char *username   = NULL;
+char *hostname   = NULL;
+char *rcsd       = NULL;
+char *console    = NULL;

 static void parse_kernel_cmdline(void)
 {
@@ -73,7 +73,7 @@ static int run_loop(void)
 	return 0;
 }

-int main(int UNUSED(args), char *argv[])
+int main(int UNUSED(args), char* UNUSED(argv[]))
 {
 	/*
 	 * Initial setup of signals, ignore all until we're up.
@@ -135,6 +135,7 @@ int main(int UNUSED(args), char *argv[])
 #ifdef SYSROOT
 	run(SYSROOT, "/", NULL, MS_MOVE, NULL);
 #endif
+
 	_d("Root FS up, calling hooks ...");
 	plugin_run_hooks(HOOK_ROOTFS_UP);

@@ -193,9 +194,8 @@ int main(int UNUSED(args), char *argv[])
 	 */
 	plugin_run_hooks(HOOK_SYSTEM_UP);

-	/* Start GETTY on console */
-	_d("Starting getty on console ...");
-	run_getty(GETTY, argv);
+	/* Start GETTY on console(s) */
+	tty_start();

 	/*
 	 * Enter main loop to monior /dev/initctl and services
@@ -38,11 +38,11 @@
 #if defined EMBEDDED_SYSTEM
 # define CONSOLE        "/dev/console"
 # define MDEV           "/sbin/mdev"
-# define GETTY          "/sbin/getty -L 115200 ttyS0 vt100"
+# define GETTY          "/sbin/getty -L 115200 %s vt100"
 #else /* Debian/Ubuntu based distributions */
 # define RANDOMSEED	"/var/lib/urandom/random-seed"
 # define CONSOLE        "/dev/tty1"
-# define GETTY		"/sbin/getty -8 38400 tty1"
+# define GETTY		"/sbin/getty -8 38400 %s"
 # define REMOUNT_ROOTFS_RW
 # define RUNLEVEL	2
 # define USE_UDEV
@@ -62,15 +62,20 @@
 #define USERNAME_SIZE 16
 #define HOSTNAME_SIZE 32

-extern char *sdown;
-extern char *network;
-extern char *hostname;
-extern char *username;
-extern char *rcsd;
+extern char  *sdown;
+extern char  *network;
+extern char  *hostname;
+extern char  *username;
+extern char  *rcsd;
+extern char  *console;

 /* conf.c */
 void parse_finit_conf(char *file);

+/* tty.c */
+void tty_start(void);
+int  tty_add(char *tty, int baud);
+
 #endif /* FINIT_H_ */

 /**
@@ -250,21 +250,6 @@ char *pid_get_name(pid_t pid, char *name, size_t len)
 	return name;
 }

-
-/**
- * procname_set - Change process name, as seen in process listnings
- * @name: New name of process
- * @args: The process' argv[] vector.
- */
-void procname_set(char *name, char *args[])
-{
-	size_t len = strlen(args[0]) + 1; /* Include terminating '\0' */
-
-	prctl(PR_SET_NAME, name, 0, 0, 0);
-	memset(args[0], 0, len);
-	strlcpy(args[0], name, len);
-}
-
 /**
 * procname_kill - Send a signal to a process group by name.
 * @name: Name of process to send signal to.
@@ -507,7 +492,7 @@ int run_interactive(char *cmd, char *fmt, ...)
 	return status;
 }

-pid_t run_getty(char *cmd, char *argv[])
+pid_t run_getty(char *cmd, int console)
 {
 	pid_t pid = fork();

@@ -517,31 +502,32 @@ pid_t run_getty(char *cmd, char *argv[])
 		sigset_t nmask;
 		struct sigaction sa;

-		/* Detach from initial controlling TTY */
-		vhangup();
+		if (console) {
+			/* Detach from initial controlling TTY */
+			vhangup();

-		close(2);
-		close(1);
-		close(0);
+			close(2);
+			close(1);
+			close(0);

-		/* Attach TTY to console */
-		if (open(CONSOLE, O_RDWR) != 0)
-			exit(1);
+			/* Attach TTY to console */
+			if (open(CONSOLE, O_RDWR) != 0)
+				exit(1);

+			dup2(0, STDIN_FILENO);
+			dup2(0, STDOUT_FILENO);
+			dup2(0, STDERR_FILENO);
+
+			prctl(PR_SET_NAME, "console", 0, 0, 0);
+		}
 		sigemptyset(&nmask);
 		sigaddset(&nmask, SIGCHLD);
 		sigprocmask(SIG_UNBLOCK, &nmask, NULL);

 		/* Reset signal handlers that were set by the parent process */
-                for (i = 1; i < NSIG; i++)
+		for (i = 1; i < NSIG; i++)
 			DFLSIG(sa, i, 0);

-		dup2(0, STDIN_FILENO);
-		dup2(0, STDOUT_FILENO);
-		dup2(0, STDERR_FILENO);
-
-		procname_set("console", argv);
-
 		while (!fexist(SYNC_SHUTDOWN)) {
 			static const char msg[] = "\nPlease press Enter to activate this console. ";

@@ -550,10 +536,11 @@ pid_t run_getty(char *cmd, char *argv[])
 				continue;
 			}

-			i = write(STDERR_FILENO, msg, sizeof(msg) - 1);
-			while (read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
-				continue;
-
+			if (console) {
+				i = write(STDERR_FILENO, msg, sizeof(msg) - 1);
+				while (read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
+					continue;
+			}
 			if (fexist(SYNC_STOPPED))
 				continue;

@@ -88,7 +88,7 @@ void    set_hostname    (char *hostname);

 int     run             (char *cmd);
 int     run_interactive (char *cmd, char *fmt, ...);
-pid_t   run_getty       (char *cmd, char *argv[]);
+pid_t   run_getty       (char *cmd, int console);
 int	run_parts	(char *dir, char *cmd);

 /* strlcpy.c */
@@ -0,0 +1,138 @@
+/* TTY handling in finit
+ *
+ * Copyright (c) 2013 Mattias Walström <lazzer@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+#include <sys/inotify.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+
+#include "queue.h"
+#include "finit.h"
+#include "helpers.h"
+#include "lite.h"
+
+typedef struct finit_tty_t {
+	char *name;
+	int baud;
+
+	int pid; /* Runtime information*/
+} finit_tty_t;
+
+typedef struct node {
+	LIST_ENTRY(node) link;
+	finit_tty_t data;
+} node_t;
+
+
+/* We need to make room for the filename also, which is sent after inotify_event. */
+#define EVENT_SIZE ((sizeof(struct inotify_event) + FILENAME_MAX))
+
+LIST_HEAD(, node) node_list = LIST_HEAD_INITIALIZER();
+int tty_add(char *tty, int baud)
+{
+	node_t *entry = malloc(sizeof(*entry));
+
+	if (!entry)
+		return errno = ENOMEM;
+
+	entry->data.name = tty;
+	entry->data.baud = baud;
+
+	LIST_INSERT_HEAD(&node_list, entry, link);
+
+	return 0;
+}
+
+static void tty_startstop_one(finit_tty_t *tty, uint32_t mask)
+{
+	char cmd[strlen(GETTY)+FILENAME_MAX];
+
+	if (mask & IN_CREATE) {
+		_d("Starting %s as %s", tty->name, (strcmp(tty->name, console) == 0) ? "console" : "TTY");
+		snprintf(cmd, sizeof(cmd), GETTY, tty->name);
+		tty->pid = run_getty(cmd, strcmp(tty->name, console) == 0);
+	}
+
+	/* Kill the spawned child, and recollect it. */
+	if ((mask & IN_DELETE) && tty->pid) {
+		int status = 0;
+		_d("Stopping %s", tty->name);
+		kill(tty->pid, SIGKILL);
+		waitpid(tty->pid, &status, 0);
+		tty->pid = 0;
+	}
+}
+
+void tty_start(void)
+{
+	int   fd = -1;
+	node_t *entry;
+
+	/* Start all TTYs that already exist in the system. */
+	LIST_FOREACH(entry, &node_list, link) {
+		chdir("/dev");
+		if (fexist (entry->data.name))
+			tty_startstop_one(&entry->data, IN_CREATE);
+	}
+
+	/* Start a inotify watcher to catch new TTYs that is discovered (USB for example) */
+	if (!fork()) {
+		fd = inotify_init();
+
+		prctl(PR_SET_NAME, "tty_watcher", 0, 0, 0);
+		if (inotify_add_watch(fd, "/dev", IN_CREATE | IN_DELETE) < 0) {
+			fprintf(stderr, "Failed to add watcher, errno %s\n", strerror(errno));
+			return;
+		}
+
+		while (1) {
+			int len = 0;;
+			char buf[EVENT_SIZE];
+			struct inotify_event *notified;
+
+			while ((len = read(fd, buf, EVENT_SIZE))) {
+				if (len == -1) {
+					if (errno == EAGAIN || errno == EINTR)
+						continue;
+				}
+				notified = (struct inotify_event *) &buf[0];
+				LIST_FOREACH(entry, &node_list, link) {
+					if (strcmp(notified->name, entry->data.name) == 0) {
+						tty_startstop_one(&entry->data, notified->mask);
+					}
+				}
+			}
+		}
+		exit(0);
+	}
+
+}
+
+/**
+ * Local Variables:
+ *  version-control: t
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */