support for serial login using cttyhack. remove the needed mountoints from /etc/fstab. rc_delete should remove links even if target is missing

2 files changed, 84 insertions, 1 deletions

diff --git a/src/Makefile b/src/Makefile
index 23d1a84..006fd76 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2,7 +2,7 @@
 CC = gcc
 LD = gcc
 
-SBIN_TARGETS = runscript readahead
+SBIN_TARGETS = runscript readahead cttyhack
 TARGET = $(BIN_TARGETS) $(SBIN_TARGETS)
 
 .PHONY: all clean
diff --git a/src/cttyhack.c b/src/cttyhack.c
new file mode 100644
index 0000000..e54c1ec
--- /dev/null
+++ b/src/cttyhack.c
@@ -0,0 +1,83 @@
+/* This code is adapted from busybox project
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+/* From <linux/vt.h> */
+struct vt_stat {
+	unsigned short v_active;	/* active vt */
+	unsigned short v_signal;	/* signal to send */
+	unsigned short v_state;	/* vt bitmask */
+};
+enum { VT_GETSTATE = 0x5603 };	/* get global vt state info */
+
+/* From <linux/serial.h> */
+struct serial_struct {
+	int	type;
+	int	line;
+	unsigned int	port;
+	int	irq;
+	int	flags;
+	int	xmit_fifo_size;
+	int	custom_divisor;
+	int	baud_base;
+	unsigned short	close_delay;
+	char	io_type;
+	char	reserved_char[1];
+	int	hub6;
+	unsigned short	closing_wait; /* time to wait before closing */
+	unsigned short	closing_wait2; /* no longer used... */
+	unsigned char	*iomem_base;
+	unsigned short	iomem_reg_shift;
+	unsigned int	port_high;
+	unsigned long	iomap_base;	/* cookie passed into ioremap */
+	int	reserved[1];
+};
+
+int main(int ergc, char **argv)
+{
+	int fd;
+	char console[sizeof(int)*3 + 16];
+	union {
+		struct vt_stat vt;
+		struct serial_struct sr;
+		char paranoia[sizeof(struct serial_struct) * 3];
+	} u;
+
+	if (!argv[1]) {
+		fprintf(stderr, "Usage: cttyhack cmd [arg1] [arg2]...\n");
+		return -1;
+	}
+
+	strcpy(console, "/dev/tty");
+	if (ioctl(0, TIOCGSERIAL, &u.sr) == 0) {
+		/* this is a serial console */
+		sprintf(console + 8, "S%d", u.sr.line);
+	} else if (ioctl(0, VT_GETSTATE, &u.vt) == 0) {
+		/* this is linux virtual tty */
+		sprintf(console + 8, "%d", u.vt.v_active);
+	}
+
+	if (console[8]) {
+		fd = open(console, O_RDWR);
+		if (fd >= 0) {
+		//fprintf(stderr, "cttyhack: switching to '%s'\n", console);
+			dup2(fd, 0);
+			dup2(fd, 1);
+			dup2(fd, 2);
+			while (fd > 2) close(fd--);
+		}
+	}
+
+	execvp(argv[1], argv + 1);
+	fprintf(stderr, "cttyhack: failed to exec %s: %s\n",
+				argv[1], strerror(errno));
+	return -1;
+}