Merge branch 'external-getty-support'

README.md

@@ -86,9 +86,14 @@ inetd ssh/tcp@*,!eth0  nowait [2345] /sbin/dropbear -i -R -F -- SSH service
 # Run start scripts from this directory
 # runparts /etc/start.d
 
-# Virtual consoles to start built-in getty on
+# Virtual consoles run BusyBox getty
-tty [12345] /dev/tty1    115200 linux
+tty [12345] /sbin/getty -L 115200 /dev/tty1 linux
+tty [12345] /sbin/getty -L 115200 /dev/tty2 linux
+tty [12345] /sbin/getty -L 115200 /dev/tty3 linux
+
+# Use built-in getty for serial port and USB serial
 tty [12345] /dev/ttyAMA0 115200 vt100
+tty [12345] /dev/ttyUSB0 115200 vt100
 ```
 
 The `service` stanza, as well as `task`, `run`, `inetd` and others are

doc/config.md

@@ -137,13 +137,24 @@ Syntax:
   Include another configuration file.  Absolute path required.
 
 * `tty [LVLS] <DEV> [BAUD] [TERM] [noclear]`  
-  Start the built-in getty on the given TTY device DEV, in the given
+  `tty [LVLS] <CMD> <ARGS>`  
-  runlevels.  Default baud rate is `38400`.
+  The first variant of this option uses the built-in getty on the given
+  TTY device DEV, in the given runlevels.  Default baud rate is `38400`.
 
+  **Example:**
 ```conf
         tty [12345] /dev/ttyAMA0 115200 noclear
 ```
 
+  The second variant is for using an external getty, like agetty or the
+  BusyBox getty.  There are no default settings for this variant, but a
+  word of caution: *you have give the absolute path to the TTY*.
+
+  **Example:**
+```conf
+        tty [12345] /sbin/getty -L 115200 /dev/ttyAMA0 vt100
+```
+
   On really bare bones systems Finit offers a fallback shell, but one
   can also use the `service` stanza to start a stand-alone shell:
 

src/exec.c

@@ -27,6 +27,7 @@
 #include <ctype.h>		/* isdigit() */
 #include <dirent.h>
 #include <stdarg.h>
+#include <sys/ioctl.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>
 #include <lite/lite.h>
@@ -212,30 +213,93 @@ int run_interactive(char *cmd, char *fmt, ...)
 	return status;
 }
 
+static void prepare_tty(char *tty, char *procname, int console)
+{
+	/* Reset signal handlers that were set by the parent process */
+	sig_unblock();
+	setsid();
+
+	/* Set INIT_PROCESS UTMP entry */
+	utmp_set_init(tty, 0);
+
+	if (console)
+		procname = "console";
+	prctl(PR_SET_NAME, procname, 0, 0, 0);
+}
+
 pid_t run_getty(char *tty, char *speed, char *term, int noclear, int console)
 {
 	pid_t pid;
 
 	pid = fork();
 	if (!pid) {
-		/* Reset signal handlers that were set by the parent process */
+		prepare_tty(tty, "finit-getty", console);
-		sig_unblock();
-		setsid();
-
-		/* Set INIT_PROCESS UTMP entry */
-		utmp_set_init(tty, 0);
-
-		if (console)
-			prctl(PR_SET_NAME, "console", 0, 0, 0);
-		else
-			prctl(PR_SET_NAME, "finit-getty", 0, 0, 0);
-
 		_exit(getty(tty, speed, term, noclear, NULL));
 	}
 
 	return pid;
 }
 
+pid_t run_getty2(char *tty, char *cmd, char *args[], int console)
+{
+	pid_t pid;
+
+	pid = fork();
+	if (!pid) {
+		int  i, fd;
+		struct sigaction sa;
+
+		/* Reset signal handlers that were set by the parent process */
+		for (i = 1; i < NSIG; i++)
+			DFLSIG(sa, i, 0);
+
+		/* Detach from initial controlling TTY */
+		vhangup();
+
+		close(STDERR_FILENO);
+		close(STDOUT_FILENO);
+		close(STDIN_FILENO);
+
+		/* Attach TTY to console */
+		fd = open(tty, O_RDWR);
+		if (fd != STDIN_FILENO)
+			exit(1);
+
+		dup2(fd, STDIN_FILENO);
+		dup2(fd, STDOUT_FILENO);
+		dup2(fd, STDERR_FILENO);
+
+		prepare_tty(tty, "getty", console);
+
+		if (ioctl(STDIN_FILENO, TIOCSCTTY, 1) < 0)
+			_pe("Failed TIOCSCTTY");
+
+		while (!fexist(SYNC_SHUTDOWN)) {
+			char c;
+			static const char msg[] = "\nPlease press Enter to activate this console.";
+
+			if (fexist(SYNC_STOPPED)) {
+				sleep(1);
+				continue;
+			}
+
+			(void)write(STDERR_FILENO, msg, sizeof(msg));
+			while (read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
+				continue;
+
+			if (fexist(SYNC_STOPPED))
+				continue;
+
+			_exit(execv(cmd, args));
+		}
+
+		close(fd);
+		vhangup();
+		exit(0);
+	}
+
+	return pid;
+}
 
 int run_parts(char *dir, char *cmd)
 {

src/helpers.h

@@ -64,6 +64,7 @@ int     complete        (char *cmd, int pid);
 int     run             (char *cmd);
 int     run_interactive (char *cmd, char *fmt, ...);
 pid_t   run_getty       (char *tty, char *speed, char *term, int noclear, int console);
+pid_t   run_getty2      (char *tty, char *cmd, char *args[], int console);
 int     run_parts       (char *dir, char *cmd);
 
 static inline void create(char *path, mode_t mode, uid_t uid, gid_t gid)

src/tty.c

@@ -83,12 +83,33 @@ void tty_sweep(void)
 	}
 }
 
-/* tty [!1-9,S] <DEV> [BAUD[,BAUD,...]] [TERM] [noclear] */
+/**
+ * tty_register - Register a getty on a device
+ * @line:  Configuration, text after initial "tty"
+ * @mtime: Modification time, to propagate to lower layers
+ *
+ * A Finit tty line can use the internal getty implementation or an
+ * external one, like the BusyBox getty for instance.  This function
+ * determines which one to use based on a leading '/dev' prefix.  If
+ * a leading '/dev' is encountered the remaining options must be in
+ * the following sequence:
+ *
+ *     tty [!1-9,S] <DEV> [BAUD[,BAUD,...]] [TERM] [noclear]
+ *
+ * Otherwise the leading prefix must be the full path to an existing
+ * getty implementation, with it's arguments following:
+ *
+ *     tty [!1-9,S] </path/to/getty> [ARGS]
+ *
+ * Different getty implementations prefer the TTY device argument in
+ * different order, so take care to investigate this first.
+ */
 int tty_register(char *line, struct timeval *mtime)
 {
 	tty_node_t *entry;
-	int         insert = 0, noclear = 0;
+	int         i, num = 1, insert = 0, noclear = 0;
-	char       *tok, *dev = NULL, *baud = NULL;
+	char       *tok, *cmd = NULL, *args[TTY_MAX_ARGS];
+	char             *dev = NULL, *baud = NULL;
 	char       *runlevels = NULL, *term = NULL;
 
 	if (!line) {
@@ -96,24 +117,58 @@ int tty_register(char *line, struct timeval *mtime)
 		return errno = EINVAL;
 	}
 
-	tok = strtok(line, " ");
+	tok = strchr(line, '/');
-	while (tok) {
+	if (tok && strncmp(tok, "/dev", 4)) {
-		if (tok[0] == '[')
+		/* External getty */
-			runlevels = &tok[0];
+		cmd = tok;
-		else if (tok[0] == '/')
-			dev = tok;
-		else if (isdigit(tok[0]))
-			baud = tok;
-		else if (!strcmp(tok, "noclear"))
-			noclear = 1;
-		else
-			term = tok;
 
-		tok = strtok(NULL, " ");
+		for (tok = strtok(line, " "); tok; tok = strtok(NULL, " ")) {
+			if (cmd == tok) {
+				cmd = strdup(tok);
+				continue;
+			}
+
+			if (tok[0] == '[') {
+				runlevels = &tok[0];
+				continue;
+			}
+
+			if (tok[0] == '/' && tok != cmd)
+				dev = strdup(tok);
+
+			args[num++] = strdup(tok);
+			if (num >= TTY_MAX_ARGS)
+				break;
+		}
+
+		cmd = strdup(cmd);
+		tok = strrchr(cmd, '/');
+		if (!tok)
+			tok = cmd;
+		else
+			tok++;
+		args[0] = strdup(tok);
+	} else {
+		/* Built-in getty */
+		tok = strtok(line, " ");
+		while (tok) {
+			if (tok[0] == '[')
+				runlevels = &tok[0];
+			else if (tok[0] == '/')
+				dev = strdup(tok);
+			else if (isdigit(tok[0]))
+				baud = tok;
+			else if (!strcmp(tok, "noclear"))
+				noclear = 1;
+			else
+				term = tok;
+
+			tok = strtok(NULL, " ");
+		}
 	}
 
 	if (!dev) {
-		_e("Incomplete tty, cannot register");
+		_e("Incomplete tty, no device given, cannot register.");
 		return errno = EINVAL;
 	}
 
@@ -121,15 +176,24 @@ int tty_register(char *line, struct timeval *mtime)
 	if (!entry) {
 		insert = 1;
 		entry = calloc(1, sizeof(*entry));
-		if (!entry)
+		if (!entry) {
+			free(dev);
 			return errno = ENOMEM;
+		}
 	}
 
-	entry->data.name = strdup(dev);
+	entry->data.name = dev;
 	entry->data.baud = baud ? strdup(baud) : NULL;
 	entry->data.term = term ? strdup(term) : NULL;
 	entry->data.noclear = noclear;
 	entry->data.runlevels = conf_parse_runlevels(runlevels);
+
+	/* External getty */
+	entry->data.cmd  = cmd;
+	for (i = 0; i < num && i < TTY_MAX_ARGS; i++)
+		entry->data.args[i] = args[i];
+	entry->data.args[++i] = NULL;
+
 	_d("Registering tty %s at %s baud with term=%s on runlevels %s",
 	   dev, baud ?: "NULL", term ?: "N/A", runlevels ?: "[2-5]");
 
@@ -155,6 +219,15 @@ int tty_unregister(tty_node_t *tty)
 		free(tty->data.baud);
 	if (tty->data.term)
 		free(tty->data.term);
+	if (tty->data.cmd) {
+		int i;
+
+		free(tty->data.cmd);
+		for (i = 0; tty->data.args[i] && i < TTY_MAX_ARGS; i++) {
+			free(tty->data.args[i]);
+			tty->data.args[i] = NULL;
+		}
+	}
 	free(tty);
 
 	return 0;
@@ -275,7 +348,10 @@ void tty_start(finit_tty_t *tty)
 		return;
 	}
 
-	tty->pid = run_getty(dev, tty->baud, tty->term, tty->noclear, is_console);
+	if (!tty->cmd)
+		tty->pid = run_getty(dev, tty->baud, tty->term, tty->noclear, is_console);
+	else
+		tty->pid = run_getty2(dev, tty->cmd, tty->args, is_console);
 }
 
 void tty_stop(finit_tty_t *tty)

src/tty.h

@@ -28,6 +28,7 @@
 #include <limits.h>
 #include <lite/queue.h>		/* BSD sys/queue.h API */
 
+#define TTY_MAX_ARGS 16
 #define EVENT_SIZE ((sizeof(struct inotify_event) + NAME_MAX + 1))
 
 typedef struct {
@@ -37,6 +38,9 @@ typedef struct {
 	int    noclear;
 	int    runlevels;
 
+	char  *cmd;		/* NULL when running built-in getty */
+	char  *args[TTY_MAX_ARGS];
+
 	int    pid;
 } finit_tty_t;