Rewrite init(8).

Makefile

@@ -88,12 +88,15 @@ endif
 	rm -rf "$(INSTALL_ROOTFS)/boot/sortix.initrd.d"
 	mkdir -p "$(INSTALL_ROOTFS)/boot/sortix.initrd.d"
 	mkdir -p "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/bin"
-	for PROGRAM in init mbrfs extfs; do \
-	  cp "$(INSTALL_ROOTFS)/bin/$$PROGRAM" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/bin/$$PROGRAM"; \
-	done
+	mkdir -p "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/sbin"
+	test ! -e "$(INSTALL_ROOTFS)/bin/fsck.ext2" || \
+	cp "$(INSTALL_ROOTFS)/bin/fsck.ext2" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/bin/fsck.ext2"
+	cp "$(INSTALL_ROOTFS)/sbin/extfs" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/sbin/extfs"
+	cp "$(INSTALL_ROOTFS)/sbin/init" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/sbin/init"
 	mkdir -p "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/etc"
 	mkdir -p "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/etc/init"
-	cp "$(INSTALL_ROOTFS)/etc/rootfs.uuid" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/etc/init/rootfs.uuid"
+	cp "$(INSTALL_ROOTFS)/etc/fstab" "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/etc/fstab"
+	echo chain > "$(INSTALL_ROOTFS)/boot/sortix.initrd.d/etc/init/target"
 	mkinitrd --format=sortix-initrd-2 "$(INSTALL_ROOTFS)/boot/sortix.initrd.d" -o "$(INSTALL_ROOTFS)/boot/sortix.initrd"
 	rm -rf "$(INSTALL_ROOTFS)/boot/sortix.initrd.d"
 

ext/Makefile

@@ -24,8 +24,8 @@ all: $(BINARIES)
 .PHONY: all install clean
 
 install: all
-	mkdir -p $(DESTDIR)$(BINDIR)
-	install $(BINARIES) $(DESTDIR)$(BINDIR)
+	mkdir -p $(DESTDIR)$(SBINDIR)
+	install $(BINARIES) $(DESTDIR)$(SBINDIR)
 
 extfs: *.cpp *.h
 	$(CXX) $(PTHREAD_OPTION) -std=gnu++11 $(CPPFLAGS) $(CXXFLAGS) *.cpp -o $@ $(LIBS)

ext/extfs.cpp

@@ -128,66 +128,6 @@ void StatInode(Inode* inode, struct stat* st)
 	st->st_blocks = inode->data->i_blocks;
 }
 
-static bool is_hex_digit(char c)
-{
-	return ('0' <= c && c <= '9') ||
-	       ('a' <= c && c <= 'f') ||
-	       ('A' <= c && c <= 'F');
-}
-
-static bool is_valid_uuid(const char* uuid)
-{
-	if ( strlen(uuid) != 36 )
-		return false;
-	// Format: 01234567-0123-0123-0123-0123456789AB
-	for ( size_t i = 0; i < 36; i++ )
-	{
-		if ( i == 8 || i == 13 || i == 18 || i == 23 )
-		{
-			if ( uuid[i] != '-' )
-				return false;
-		}
-		else
-		{
-			if ( !is_hex_digit(uuid[i]) )
-				return false;
-		}
-	}
-	return true;
-}
-
-static unsigned char debase(char c)
-{
-	if ( '0' <= c && c <= '9' )
-		return (unsigned char) (c - '0');
-	if ( 'a' <= c && c <= 'f' )
-		return (unsigned char) (c - 'a' + 10);
-	if ( 'A' <= c && c <= 'F' )
-		return (unsigned char) (c - 'A' + 10);
-	return 0;
-}
-
-static void uuid_from_string(uint8_t uuid[16], const char* string)
-{
-	assert(is_valid_uuid(string));
-	size_t output_index = 0;
-	size_t i = 0;
-	while ( i < 36 )
-	{
-		assert(string[i + 0] != '\0');
-		if ( i == 8 || i == 13 || i == 18 || i == 23 )
-		{
-			i++;
-			continue;
-		}
-		assert(string[i + 1] != '\0');
-		uuid[output_index++] = debase(string[i + 0]) << 4 |
-		                       debase(string[i + 1]) << 0;
-		i += 2;
-	}
-	assert(string[i] == '\0');
-}
-
 static void compact_arguments(int* argc, char*** argv)
 {
 	for ( int i = 0; i < *argc; i++ )
@@ -217,9 +157,8 @@ static void version(FILE* fp, const char* argv0)
 int main(int argc, char* argv[])
 {
 	const char* argv0 = argv[0];
-	const char* test_uuid = NULL;
+	const char* pretend_mount_path = NULL;
 	bool foreground = false;
-	bool probe = false;
 	bool read = false;
 	bool write = false;
 	for ( int i = 1; i < argc; i++ )
@@ -250,20 +189,21 @@ int main(int argc, char* argv[])
 			foreground = false;
 		else if ( !strcmp(arg, "--foreground") )
 			foreground = true;
-		else if ( !strcmp(arg, "--probe") )
-			probe = true;
 		else if ( !strcmp(arg, "--read") )
 			read = true;
 		else if ( !strcmp(arg, "--write") )
 			write = true;
-		else if ( !strcmp(arg, "--test-uuid") )
+		else if ( !strncmp(arg, "--pretend-mount-path=", strlen("--pretend-mount-path=")) )
+			pretend_mount_path = arg + strlen("--pretend-mount-path=");
+		else if ( !strcmp(arg, "--pretend-mount-path") )
 		{
 			if ( i+1 == argc )
 			{
-				fprintf(stderr, "%s:  --test-uuid: Missing operand\n", argv0);
+				fprintf(stderr, "%s: --pretend-mount-path: Missing operand\n", argv0);
 				exit(1);
 			}
-			test_uuid = argv[++i], argv[i] = NULL;
+			pretend_mount_path = argv[++i];
+			argv[i] = NULL;
 		}
 		else
 		{
@@ -296,6 +236,9 @@ int main(int argc, char* argv[])
 		exit(1);
 	}
 
+	if ( !pretend_mount_path )
+		pretend_mount_path = mount_path;
+
 	int fd = open(device_path, write ? O_RDWR : O_RDONLY);
 	if ( fd < 0 )
 		error(1, errno, "`%s'", device_path);
@@ -304,74 +247,35 @@ int main(int argc, char* argv[])
 	struct ext_superblock sb;
 	if ( preadall(fd, &sb, sizeof(sb), 1024) != sizeof(sb) )
 	{
-		if ( probe )
-			exit(1);
-		else if ( errno == EEOF )
+		if ( errno == EEOF )
 			error(1, 0, "`%s' isn't a valid extended filesystem", device_path);
 		else
 			error(1, errno, "read: `%s'", device_path);
 	}
 
 	// Verify the magic value to detect a compatible filesystem.
-	if ( !probe && sb.s_magic != EXT2_SUPER_MAGIC )
+	if ( sb.s_magic != EXT2_SUPER_MAGIC )
 		error(1, 0, "`%s' isn't a valid extended filesystem", device_path);
 
-	if ( probe && sb.s_magic != EXT2_SUPER_MAGIC )
-		exit(1);
-
-	// Test whether this was the filesystem the user was looking for.
-	if ( test_uuid )
-	{
-		if ( !is_valid_uuid(test_uuid) )
-		{
-			if ( !probe )
-				error(1, 0, "`%s' isn't a valid uuid", test_uuid);
-			exit(1);
-		}
-
-		uint8_t uuid[16];
-		uuid_from_string(uuid, test_uuid);
-
-		if ( memcmp(sb.s_uuid, uuid, 16) != 0 )
-		{
-			if ( !probe )
-				error(1, 0, "uuid `%s' did not match the ext2 filesystem at `%s'", test_uuid, device_path);
-			exit(1);
-		}
-	}
-
 	// Test whether this revision of the extended filesystem is supported.
 	if ( sb.s_rev_level == EXT2_GOOD_OLD_REV )
-	{
-		if ( probe )
-			exit(1);
 		error(1, 0, "`%s' is formatted with an obsolete filesystem revision",
 		            device_path);
-	}
 
 	// Verify that no incompatible features are in use.
 	if ( sb.s_feature_compat & ~EXT2_FEATURE_INCOMPAT_SUPPORTED )
-	{
-		if ( probe )
-			exit(1);
 		error(1, 0, "`%s' uses unsupported and incompatible features",
 		            device_path);
-	}
 
 	// Verify that no incompatible features are in use if opening for write.
 	if ( !default_access && write &&
 	     sb.s_feature_ro_compat & ~EXT2_FEATURE_RO_COMPAT_SUPPORTED )
-	{
-		if ( probe )
-			exit(1);
 		error(1, 0, "`%s' uses unsupported and incompatible features, "
 		            "read-only access is possible, but write-access was "
 		            "requested", device_path);
-	}
 
 	if ( write && sb.s_feature_ro_compat & ~EXT2_FEATURE_RO_COMPAT_SUPPORTED )
 	{
-		if ( !probe )
 		fprintf(stderr, "Warning: `%s' uses unsupported and incompatible "
 		                "features, falling back to read-only access\n",
 		                device_path);
@@ -380,22 +284,13 @@ int main(int argc, char* argv[])
 	}
 
 	// Check whether any features are in use that we can safely disregard.
-	if ( !probe && sb.s_feature_compat & ~EXT2_FEATURE_COMPAT_SUPPORTED )
+	if ( sb.s_feature_compat & ~EXT2_FEATURE_COMPAT_SUPPORTED )
 		fprintf(stderr, "Note: filesystem uses unsupported but compatible "
 		                "features\n");
 
 	// Check the block size is sane. 64 KiB may have issues, 32 KiB then.
 	if ( sb.s_log_block_size > (15-10) /* 32 KiB blocks */ )
-	{
-		if ( probe )
-			exit(1);
 		error(1, 0, "`%s': excess block size", device_path);
-	}
-
-	// We have found no critical problems, so let the caller know that this
-	// filesystem satisfies the probe request.
-	if ( probe )
-		exit(0);
 
 	// Check whether the filesystem was unmounted cleanly.
 	if ( sb.s_state != EXT2_VALID_FS )
@@ -407,7 +302,7 @@ int main(int argc, char* argv[])
 	Device* dev = new Device(fd, device_path, block_size, write);
 	if ( !dev ) // TODO: Use operator new nothrow!
 		error(1, errno, "malloc");
-	Filesystem* fs = new Filesystem(dev, mount_path);
+	Filesystem* fs = new Filesystem(dev, pretend_mount_path);
 	if ( !fs ) // TODO: Use operator new nothrow!
 		error(1, errno, "malloc");
 

init/Makefile

@@ -19,14 +19,16 @@ all: $(BINARY)
 .PHONY: all install clean
 
 $(BINARY): $(OBJS)
-	$(CXX) $(OBJS) -o $(BINARY) $(CXXFLAGS) $(LIBS)
+	$(CXX) $(OBJS) -o $(BINARY) $(CXXFLAGS) -lmount $(LIBS)
 
 %.o: %.c++
 	$(CXX) -std=gnu++11 $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
 
 install: all
-	mkdir -p $(DESTDIR)$(BINDIR)
-	install $(BINARY) $(DESTDIR)$(BINDIR)
+	mkdir -p $(DESTDIR)$(SBINDIR)
+	install $(BINARY) $(DESTDIR)$(SBINDIR)
+	mkdir -p $(DESTDIR)$(MANDIR)/man8
+	cp init.8 $(DESTDIR)$(MANDIR)/man8/init.8
 
 clean:
 	rm -f $(BINARY) $(OBJS) *.o

init/init.8

@@ -0,0 +1,182 @@
+.Dd $Mdocdate: October 5 2015 $
+.Dt INIT 8
+.Os
+.Sh NAME
+.Nm init
+.Nd system initialization
+.Sh SYNOPSIS
+.Nm init
+.Op Fl \-target Ns "=" Ns Ar init-target
+.Op Fl \-chain Ns "=" Ns Ar path-or-uuid
+.Sh DESCRIPTION
+.Nm
+is the first program run after system startup and is responsible for
+initializing the operating system and starting the specified
+.Ar init-target .
+This is normally a login screen, a root shell, or a dedicated special purpose
+program.
+.Pp
+The
+.Xr kernel 7
+starts the system in a temporary environment with a root filesystem
+backed by system memory and extracts the
+.Xr initrd 7
+into it.  The kernel runs the
+.Pa /sbin/init
+program of the system memory root filesystem as the first process.  If the
+system is bootable cdrom, then the initrd will be a fully functional system and
+.Nm
+will start a live environment or an operating system installer.  If the
+system is installed on a harddisk, then the initrd is a minimal system made with
+.Xr update-initrd 8
+that will search for the actual root filesystem and chain init it.  The next
+stage init will recognize it as the intended system and complete the system
+startup.
+.Ss Initialization Target
+.Nm
+first determines its target from the
+.Fl \-target
+option if specified or
+.Pa /etc/init/target
+otherwise. Supported targets are:
+.Pp
+.Bl -tag -width "single-user" -compact -offset indent
+.It chain
+mount real root filesystem and run its
+.Nm
+.It multi-user
+boot to
+.Xr login 8
+.It single-user
+boot to root shell without password (not secure)
+.It sysinstall
+boot to operating system installer (not secure)
+.It sysupgrade
+boot to operating system upgrader (not secure)
+.El
+.Pp
+It is a full system compromise if unauthenticated users are able to boot the
+wrong target.  The kernel command line can specify the path to
+.Nm
+and its arguments.  Unprivileged users can change the kernel command line from
+the bootloader command line if it hasn't been password protected.  Likewise
+unprivileged users can use their own replacement bootloader by booting a
+portable device under their control if the firmware configuration has not been
+password protected.
+.Ss Partition Creation
+.Nm
+will scan every block device for valid partition tables and create the
+corresponding partition devices in
+.Pa /dev .
+.Ss Chain Initialization
+The chain target triggers a search for the root filesystem.  The
+.Fl \-chain Ns "=" Ns Ar path-or-uuid
+option implies
+.Fl \-target Ns "=" Ns chain
+if it is not set and specifies the method to locate the root filesystem.  The
+.Ar path-or-uuid
+value is either a path to a directory, in which case it is used as the root
+filesystem, or a file that contains a uuid of the root filesystem, or it can be
+a valid uuid of the intended root filesystem.  If the
+.Fl \-chain
+option is not specified, the root filesystem of
+.Pa /etc/fstab
+is used as described in
+.Xr fstab 5 .
+.Pp
+Every block device and partition is scanned to determine if it is the filesystem
+by matching the desired uuid.  The root filesystem is checked for consistency
+and mounted at
+.Pa /tmp/fs.XXXXXX
+and the
+.Pa /dev
+filesystem directory is bound at
+.Pa /tmp/fs.XXXXXX/dev .
+.Pp
+Finally the
+.Pa /sbin/init
+program of the target root filesystem is run inside a chroot.
+.Ss Configuration
+Once the
+.Nm
+of the real root filesystem runs, it will process basic configuration files and
+apply them:
+.Pp
+.Bl -tag -width "/etc/videomode" -compact -offset indent
+.It Pa /etc/hostname
+set hostname (see
+.Xr hostname 5 )
+.It Pa /etc/kblayout
+set keyboard layout (see
+.Xr kblayout 5 )
+.It Pa /etc/videomode
+set graphics resolution (see
+.Xr videomode 5 )
+.El
+.Ss Session
+Finally
+.Nm
+will start the target program according to its initialization target.  This will
+be a login screen, a root shell, or something else.  If the process exits
+abnormally
+.Nm
+will automatically restart it.
+.Nm
+will exit with the same exit status as the process if it exits
+normally.  The kernel decides whether to power off, reboot or halt based on this
+exit status.
+.Sh ENVIRONMENT
+.Nm
+sets the following environment variables.
+.Bl -tag -width "INIT_PID"
+.It Ev HOME
+root's home directory
+.It Ev INIT_PID
+.Nm Ns 's
+process id
+.It Ev LOGNAME
+root
+.It Ev PATH
+.Pa /bin:/sbin
+.It Ev SHELL
+root's shell
+.It Ev TERM
+sortix
+.It Ev USER
+root
+.El
+.Sh FILES
+.Bl -tag -width "/etc/init/target" -compact
+.It Pa /etc/init/target
+default initialization target
+.It Pa /etc/fstab
+filesystem table (see
+.Xr fstab 5 )
+.It Pa /etc/hostname
+hostname (see
+.Xr hostname 5 )
+.It Pa /etc/kblayout
+keyboard layout (see
+.Xr kblayout 5 )
+.It Pa /etc/videomode
+graphics resolution (see
+.Xr videomode 5 )
+.El
+.Sh EXIT STATUS
+.Nm
+exits 0 if the kernel should power off, exits 1 if the kernel should reboot, or
+exits 2 if the boot failed and the kernel should halt.  Any other exit by the
+initial
+.Nm
+will trigger a kernel panic.
+.Nm
+exits with the same exit status as its target session if it terminates normally.
+.Sh SEE ALSO
+.Xr fstab 5 ,
+.Xr hostname 5 ,
+.Xr kblayout 5 ,
+.Xr videomode 5 ,
+.Xr initrd 7 ,
+.Xr kernel 7 ,
+.Xr login 8 ,
+.Xr update-initrd 8

kernel/kernel.cpp

@@ -586,8 +586,14 @@ static void BootThread(void* /*user*/)
 
 	switch ( status )
 	{
-	case 0: CPU::ShutDown();
-	case 1: CPU::Reboot();
+	case 0:
+		CPU::ShutDown();
+	case 1:
+		CPU::Reboot();
+	case 2:
+		Log::Print("kernel: fatal: Halting system due to init fatality\n");
+		Log::Sync();
+		HaltKernel();
 	default:
 		PanicF("Init returned with unexpected return code %i", status);
 	}
@@ -618,7 +624,7 @@ static void InitThread(void* /*user*/)
 
 	dtable.Reset();
 
-	static char default_init_cmdline[] = "/bin/init";
+	static char default_init_cmdline[] = "/sbin/init";
 	if ( !init_cmdline )
 		init_cmdline = default_init_cmdline;
 

share/man/man5/videomode.5

@@ -0,0 +1,46 @@
+.Dd $Mdocdate: October 5 2015 $
+.Dt VIDEOMODE 5
+.Os
+.Sh NAME
+.Nm videomode
+.Nd initial graphics resolution
+.Sh SYNOPSIS
+.Nm /etc/videomode
+.Sh DESCRIPTION
+The
+.Nm videomode
+file is read on boot by
+.Xr init 8
+and is used as the initial graphics resolution on the primary monitor.  The
+resolution provided by the bootloader remains in effect if the file is missing.
+The resolution is usable only if the graphics card has a driver and the
+resolution is supported.
+.Sh FORMAT
+.Ar width Ns x Ns Ar height Ns x Ns Ar bits-per-pixel
+.Pp
+The file specifies a graphics resolution as a single line with three numeric
+fields separated by x characters and no whitespace whatsoever.  The first field
+is used as the
+.Ar width
+in pixels, the second field is used as the
+.Ar height
+in pixels, and the third field is used as the
+.Ar bits-per-pixel .
+.Sh FILES
+.Bl -tag -width "/etc/videomode" -compact
+.It Pa /etc/videomode
+primary monitor graphics resolution.
+.El
+.Sh EXAMPLES
+.Bd -literal
+1920x1080x32
+.Ed
+.Sh SEE ALSO
+.Xr chvideomode 1 ,
+.Xr dispmsg_issue 2 ,
+.Xr init 8
+.Sh BUGS
+This scheme only supports a single monitor.  The kernel console doesn't handle
+resolution changes gracefully, the console will be cleared and the console
+cursor might be out of the screen upon resolution shrink.  Early boot messages
+will be unavailable.

share/man/man7/initrd.7

@@ -14,7 +14,7 @@ that extracts it into the initial kernel memory root filesystem.  The kernel
 invokes the
 .Xr init 8
 extracted from the initrd as
-.Pa /bin/init .
+.Pa /sbin/init .
 .Pp
 The initrd is in the custom format made by
 .Xr mkinitrd 8

share/man/man7/kernel.7

@@ -22,7 +22,7 @@ The kernel extracts the initrd into the initial kernel memory root filesystem
 and executes
 .Xr init 8
 as
-.Pa /bin/init .
+.Pa /sbin/init .
 The computer is powered off if this process exits 0, rebooted if it exits 1,
 halted if it exits 2, and paniced otherwise.
 .Pp