openvt,getty,vfork_daemon_rexec,mount: tighten up fd cleanup code

(will close all fd's > 2 on daemonization now)
getty: fix "getty -" support, and also do not try to chown/chmod "-"
telnetd: fix "lost ctty" bug
Yet another attempt on saner function names:
bb_sanitize_server_stdio(0/1) -> bb_sanitize_stdio() + bb_daemonize();

15 files changed, 57 insertions, 54 deletions

diff --git a/console-tools/openvt.c b/console-tools/openvt.c
index f1cf564..c7b3e4f 100644
--- a/console-tools/openvt.c
+++ b/console-tools/openvt.c
@@ -17,7 +17,6 @@ int openvt_main(int argc, char **argv)
 	int fd;
 	char vtname[sizeof(VC_FORMAT) + 2];
 
-
 	if (argc < 3) {
 		bb_show_usage();
 	}
@@ -25,18 +24,16 @@ int openvt_main(int argc, char **argv)
 	sprintf(vtname, VC_FORMAT, (int)xatoul_range(argv[1], 1, 63));
 
 	if (fork() == 0) {
-		/* leave current vt */
-		if (setsid() < 0) {
-			bb_perror_msg_and_die("setsid");
-		}
-		close(0);			/* so that new vt becomes stdin */
-
+		/* child */
+		/* leave current vt (controlling tty) */
+		setsid();
 		/* and grab new one */
 		fd = xopen(vtname, O_RDWR);
-
-		/* Reassign stdout and sterr */
+		/* Reassign stdin, stdout and sterr */
+		dup2(fd, STDIN_FILENO);
 		dup2(fd, STDOUT_FILENO);
 		dup2(fd, STDERR_FILENO);
+		while (fd > 2) close(fd--);
 
 		execvp(argv[2], &argv[2]);
 		_exit(1);
diff --git a/debianutils/start_stop_daemon.c b/debianutils/start_stop_daemon.c
index 521b43d..9a865f6 100644
--- a/debianutils/start_stop_daemon.c
+++ b/debianutils/start_stop_daemon.c
@@ -291,8 +291,8 @@ int start_stop_daemon_main(int argc, char **argv)
 	}
 	*--argv = startas;
 	if (opt & OPT_BACKGROUND) {
-		xdaemon(0, 0);
 		setsid();
+		bb_daemonize();
 	}
 	if (opt & OPT_MAKEPID) {
 		/* user wants _us_ to make the pidfile */
diff --git a/include/libbb.h b/include/libbb.h
index 2089d23..7721cbf 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -268,7 +268,9 @@ extern void xsetgid(gid_t gid);
 extern void xsetuid(uid_t uid);
 extern void xdaemon(int nochdir, int noclose);
 /* More clever/thorough xdaemon */
-extern void bb_sanitize_server_stdio(int daemonize);
+extern void bb_sanitize_stdio_maybe_daemonize(int daemonize);
+extern void bb_sanitize_stdio(void);
+extern void bb_daemonize(void);
 extern void xchdir(const char *path);
 extern void xsetenv(const char *key, const char *value);
 extern int xopen(const char *pathname, int flags);
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 81ae126..26d1826 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -35,8 +35,8 @@ void vfork_daemon_rexec(int nochdir, int noclose,
 		dup2(fd, STDIN_FILENO);
 		dup2(fd, STDOUT_FILENO);
 		dup2(fd, STDERR_FILENO);
-		if (fd > 2)
-			close(fd);
+		while (fd > 2)
+			close(fd--);
 	}
 
 	vfork_args = xzalloc(sizeof(char *) * (argc + 3));
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index 84d4741..dc160bf 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -509,7 +509,7 @@ void xdaemon(int nochdir, int noclose)
 }
 #endif
 
-void bb_sanitize_server_stdio(int daemonize)
+void bb_sanitize_stdio_maybe_daemonize(int daemonize)
 {
 	int fd;
 	/* Mega-paranoid */
@@ -523,8 +523,8 @@ void bb_sanitize_server_stdio(int daemonize)
 		if (pid) /* parent */
 			exit(0);
     		/* child */
-		setsid();
 		/* if daemonizing, make sure we detach from stdio */
+		setsid();
 		dup2(fd, 0);
 		dup2(fd, 1);
 		dup2(fd, 2);
@@ -532,6 +532,14 @@ void bb_sanitize_server_stdio(int daemonize)
 	while (fd > 2)
 		close(fd--); /* close everything after fd#2 */
 }
+void bb_sanitize_stdio(void)
+{
+	bb_sanitize_stdio_maybe_daemonize(0);
+}
+void bb_daemonize(void)
+{
+	bb_sanitize_stdio_maybe_daemonize(1);
+}
 
 // Die with an error message if we can't open a new socket.
 int xsocket(int domain, int type, int protocol)
diff --git a/loginutils/getty.c b/loginutils/getty.c
index 5ceaefc..be49389 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -211,7 +211,7 @@ static void parse_args(int argc, char **argv, struct options *op)
 		bb_show_usage();
 
 	/* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
-	if ('0' <= argv[0][0] && argv[0][0] <= '9') {
+	if (isdigit(argv[0][0])) {
 		/* a number first, assume it's a speed (BSD style) */
 		parse_speeds(op, argv[0]);       /* baud rate(s) */
 		op->tty = argv[1]; /* tty name */
@@ -255,10 +255,8 @@ static void open_tty(char *tty, struct termios *tp, int local)
 
 		debug("open(2)\n");
 		fd = xopen(tty, O_RDWR | O_NONBLOCK);
-		if (fd) {
-			xdup2(fd, 0, tty);
-			close(fd);
-		}
+		xdup2(fd, 0, tty);
+		while (fd > 2) close(fd--);
 	} else {
 		/*
 		 * Standard input should already be connected to an open port. Make
@@ -327,8 +325,10 @@ static void open_tty(char *tty, struct termios *tp, int local)
 		}
 	}
 #else
-	chown(tty, 0, 0);        /* root, sys */
-	chmod(tty, 0622);        /* crw--w--w- */
+	if (NOT_LONE_DASH(tty)) {
+		chown(tty, 0, 0);        /* 0:0 */
+		chmod(tty, 0622);        /* crw--w--w- */
+	}
 #endif
 	if (chdir_to_root)
 		xchdir("/");
@@ -736,22 +736,14 @@ int getty_main(int argc, char **argv)
 	/* Already too late because of theoretical
 	 * possibility of getty --help somehow triggered
 	 * inadvertently before we reach this. Oh well. */
-	close(0);
-	close(1);
-	close(2);
 	logmode = LOGMODE_NONE;
-#ifdef __linux__
 	setsid();
-#endif
-	/* Was "/dev/console". Why should we spam *system console*
-	 * if there is a problem with getty on /dev/ttyS15?... */
 	nullfd = xopen(bb_dev_null, O_RDWR);
-	if (nullfd) {
-		dup2(nullfd, 0);
-		close(nullfd);
-	}
-	dup2(0, 1);
-	dup2(0, 2);
+	/* dup2(nullfd, 0); - no, because of possible "getty - 9600" */
+	/* open_tty() will take care of fd# 0 anyway */
+	dup2(nullfd, 1);
+	dup2(nullfd, 2);
+	while (nullfd > 2) close(nullfd--);
 	/* We want special flavor of error_msg_and_die */
 	die_sleep = 10;
 	msg_eol = "\r\n";
diff --git a/miscutils/setsid.c b/miscutils/setsid.c
index 347b2ba..47c44d2 100644
--- a/miscutils/setsid.c
+++ b/miscutils/setsid.c
@@ -15,9 +15,6 @@
  */
 
 #include "busybox.h"
-#include <stdio.h>
-#include <unistd.h>
-#include <stdlib.h>
 
 int setsid_main(int argc, char *argv[])
 {
@@ -25,7 +22,7 @@ int setsid_main(int argc, char *argv[])
 		bb_show_usage();
 
 	if (getpgrp() == getpid()) {
-		switch (fork()){
+		switch (fork()) {
 		case -1:
 			bb_perror_msg_and_die("fork");
 		case 0:
@@ -33,8 +30,8 @@ int setsid_main(int argc, char *argv[])
 		default:	/* parent */
 			exit(0);
 		}
-		/* child falls through */
 	}
+	/* child */
 
 	setsid();  /* no error possible */
 
diff --git a/networking/fakeidentd.c b/networking/fakeidentd.c
index 8c07082..6f766a8 100644
--- a/networking/fakeidentd.c
+++ b/networking/fakeidentd.c
@@ -1,3 +1,5 @@
+/* NB: this file is to be removed soon. See isrv_identd.c */
+
 /* vi: set sw=4 ts=4: */
 /*
  * A fake identd server
diff --git a/networking/inetd.c b/networking/inetd.c
index 370dcbb..218f85e 100644
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -1292,9 +1292,9 @@ inetd_main(int argc, char *argv[])
 		/* reexec for vfork() do continue parent */
 		vfork_daemon_rexec(0, 0, argc, argv, "-f");
 	}
-	bb_sanitize_server_stdio(0);
+	bb_sanitize_stdio();
 #else
-	bb_sanitize_server_stdio(!(opt & 2));
+	bb_sanitize_stdio_maybe_daemonize(!(opt & 2));
 #endif
 	openlog(applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
 	logmode = LOGMODE_SYSLOG;
diff --git a/networking/isrv_identd.c b/networking/isrv_identd.c
index e757d7c..2d4399c 100644
--- a/networking/isrv_identd.c
+++ b/networking/isrv_identd.c
@@ -111,7 +111,7 @@ int fakeidentd_main(int argc, char **argv)
 		bogouser = argv[optind];
 
 	/* Daemonize if no -f and no -i and no -w */
-	bb_sanitize_server_stdio(!(opt & OPT_fiw));
+	bb_sanitize_stdio_maybe_daemonize(!(opt & OPT_fiw));
 	/* Where to log in inetd modes? "Classic" inetd
 	 * probably has its stderr /dev/null'ed (we need log to syslog?),
 	 * but daemontools-like utilities usually expect that children
diff --git a/networking/telnetd.c b/networking/telnetd.c
index 51bd0c0..25cba3e 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -283,15 +283,19 @@ make_new_session(
 
 	/* child */
 
+	/* make new process group */
+	setsid();
+	tcsetpgrp(0, getpid());
+	/* ^^^ strace says: "ioctl(0, TIOCSPGRP, [pid]) = -1 ENOTTY" -- ??! */
+
 	/* open the child's side of the tty. */
-	fd = xopen(tty_name, O_RDWR /*| O_NOCTTY*/);
+	/* NB: setsid() disconnects from any previous ctty's. Therefore
+	 * we must open child's side of the tty AFTER setsid! */
+	fd = xopen(tty_name, O_RDWR); /* becomes our ctty */
 	dup2(fd, 0);
 	dup2(fd, 1);
 	dup2(fd, 2);
 	while (fd > 2) close(fd--);
-	/* make new process group */
-	setsid();
-	tcsetpgrp(0, getpid());
 
 	/* The pseudo-terminal allocated to the client is configured to operate in
 	 * cooked mode, and with XTABS CRMOD enabled (see tty(4)). */
diff --git a/networking/zcip.c b/networking/zcip.c
index 27e281c..5d57c42 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -221,7 +221,8 @@ int zcip_main(int argc, char *argv[])
 	}
 	if (opts & 4) { // -r n.n.n.n
 		if (inet_aton(r_opt, &ip) == 0
-		|| (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
+		 || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR
+		) {
 			bb_error_msg_and_die("invalid link address");
 		}
 	}
@@ -270,7 +271,7 @@ int zcip_main(int argc, char *argv[])
 	// daemonize now; don't delay system startup
 	if (!FOREGROUND) {
 		setsid();
-		xdaemon(0, 0);
+		bb_daemonize();
 		bb_info_msg("start, interface %s", intf);
 	}
 
diff --git a/shell/hush.c b/shell/hush.c
index 9bc0013..8f2dc80 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2634,8 +2634,8 @@ static void setup_job_control(void)
 
 	/* Put ourselves in our own process group.  */
 	setsid();
-	shell_pgrp = getpid ();
-	setpgid (shell_pgrp, shell_pgrp);
+	shell_pgrp = getpid();
+	setpgid(shell_pgrp, shell_pgrp);
 
 	/* Grab control of the terminal.  */
 	tcsetpgrp(shell_terminal, shell_pgrp);
@@ -2665,7 +2665,7 @@ int hush_main(int argc, char **argv)
 
 	/* Initialize some more globals to non-zero values */
 	set_cwd();
-    if (ENABLE_FEATURE_COMMAND_EDITING) cmdedit_set_initial_prompt();
+	if (ENABLE_FEATURE_COMMAND_EDITING) cmdedit_set_initial_prompt();
 	else PS1 = NULL;
 	PS2 = "> ";
 
diff --git a/shell/lash.c b/shell/lash.c
index 52b1174..b2ccaf0 100644
--- a/shell/lash.c
+++ b/shell/lash.c
@@ -1486,7 +1486,7 @@ static void setup_job_control(void)
 
 	/* Put ourselves in our own process group.  */
 	setsid();
-	shell_pgrp = getpid ();
+	shell_pgrp = getpid();
 	setpgid(shell_pgrp, shell_pgrp);
 
 	/* Grab control of the terminal.  */
diff --git a/util-linux/mount.c b/util-linux/mount.c
index b3e8c47..77382ff 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -737,7 +737,7 @@ static int daemonize(void)
 	dup2(fd, 0);
 	dup2(fd, 1);
 	dup2(fd, 2);
-	if (fd > 2) close(fd);
+	while (fd > 2) close(fd--);
 	setsid();
 	openlog(applet_name, LOG_PID, LOG_DAEMON);
 	logmode = LOGMODE_SYSLOG;