Initial commit: Linux kernel 4.19 for Unplugged OS

usr/Kconfig

@@ -0,0 +1,235 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Configuration for initramfs
+#
+
+config INITRAMFS_SOURCE
+	string "Initramfs source file(s)"
+	default ""
+	help
+	  This can be either a single cpio archive with a .cpio suffix or a
+	  space-separated list of directories and files for building the
+	  initramfs image.  A cpio archive should contain a filesystem archive
+	  to be used as an initramfs image.  Directories should contain a
+	  filesystem layout to be included in the initramfs image.  Files
+	  should contain entries according to the format described by the
+	  "usr/gen_init_cpio" program in the kernel tree.
+
+	  When multiple directories and files are specified then the
+	  initramfs image will be the aggregate of all of them.
+
+	  See <file:Documentation/early-userspace/README> for more details.
+
+	  If you are not sure, leave it blank.
+
+config INITRAMFS_FORCE
+	bool "Ignore the initramfs passed by the bootloader"
+	depends on CMDLINE_EXTEND || CMDLINE_FORCE
+	help
+	  This option causes the kernel to ignore the initramfs image
+	  (or initrd image) passed to it by the bootloader. This is
+	  analogous to CMDLINE_FORCE, which is found on some architectures,
+	  and is useful if you cannot or don't want to change the image
+	  your bootloader passes to the kernel.
+
+config INITRAMFS_ROOT_UID
+	int "User ID to map to 0 (user root)"
+	depends on INITRAMFS_SOURCE!=""
+	default "0"
+	help
+	  If INITRAMFS_SOURCE points to a directory, files owned by this UID
+	  (-1 = current user) will be owned by root in the resulting image.
+
+	  If you are not sure, leave it set to "0".
+
+config INITRAMFS_ROOT_GID
+	int "Group ID to map to 0 (group root)"
+	depends on INITRAMFS_SOURCE!=""
+	default "0"
+	help
+	  If INITRAMFS_SOURCE points to a directory, files owned by this GID
+	  (-1 = current group) will be owned by root in the resulting image.
+
+	  If you are not sure, leave it set to "0".
+
+config RD_GZIP
+	bool "Support initial ramdisk/ramfs compressed using gzip"
+	depends on BLK_DEV_INITRD
+	default y
+	select DECOMPRESS_GZIP
+	help
+	  Support loading of a gzip encoded initial ramdisk or cpio buffer.
+	  If unsure, say Y.
+
+config RD_BZIP2
+	bool "Support initial ramdisk/ramfs compressed using bzip2"
+	default y
+	depends on BLK_DEV_INITRD
+	select DECOMPRESS_BZIP2
+	help
+	  Support loading of a bzip2 encoded initial ramdisk or cpio buffer
+	  If unsure, say N.
+
+config RD_LZMA
+	bool "Support initial ramdisk/ramfs compressed using LZMA"
+	default y
+	depends on BLK_DEV_INITRD
+	select DECOMPRESS_LZMA
+	help
+	  Support loading of a LZMA encoded initial ramdisk or cpio buffer
+	  If unsure, say N.
+
+config RD_XZ
+	bool "Support initial ramdisk/ramfs compressed using XZ"
+	depends on BLK_DEV_INITRD
+	default y
+	select DECOMPRESS_XZ
+	help
+	  Support loading of a XZ encoded initial ramdisk or cpio buffer.
+	  If unsure, say N.
+
+config RD_LZO
+	bool "Support initial ramdisk/ramfs compressed using LZO"
+	default y
+	depends on BLK_DEV_INITRD
+	select DECOMPRESS_LZO
+	help
+	  Support loading of a LZO encoded initial ramdisk or cpio buffer
+	  If unsure, say N.
+
+config RD_LZ4
+	bool "Support initial ramdisk/ramfs compressed using LZ4"
+	default y
+	depends on BLK_DEV_INITRD
+	select DECOMPRESS_LZ4
+	help
+	  Support loading of a LZ4 encoded initial ramdisk or cpio buffer
+	  If unsure, say N.
+
+choice
+	prompt "Built-in initramfs compression mode"
+	depends on INITRAMFS_SOURCE!=""
+	optional
+	help
+	  This option allows you to decide by which algorithm the builtin
+	  initramfs will be compressed.  Several compression algorithms are
+	  available, which differ in efficiency, compression and
+	  decompression speed.  Compression speed is only relevant
+	  when building a kernel.  Decompression speed is relevant at
+	  each boot. Also the memory usage during decompression may become
+	  relevant on memory constrained systems. This is usually based on the
+	  dictionary size of the algorithm with algorithms like XZ and LZMA
+	  featuring large dictionary sizes.
+
+	  High compression options are mostly useful for users who are
+	  low on RAM, since it reduces the memory consumption during
+	  boot.
+
+	  Keep in mind that your build system needs to provide the appropriate
+	  compression tool to compress the generated initram cpio file for
+	  embedding.
+
+	  If in doubt, select 'None'
+
+config INITRAMFS_COMPRESSION_GZIP
+	bool "Gzip"
+	depends on RD_GZIP
+	help
+	  Use the old and well tested gzip compression algorithm. Gzip provides
+	  a good balance between compression ratio and decompression speed and
+	  has a reasonable compression speed. It is also more likely to be
+	  supported by your build system as the gzip tool is present by default
+	  on most distros.
+
+config INITRAMFS_COMPRESSION_BZIP2
+	bool "Bzip2"
+	depends on RD_BZIP2
+	help
+	  It's compression ratio and speed is intermediate. Decompression speed
+	  is slowest among the choices. The initramfs size is about 10% smaller
+	  with bzip2, in comparison to gzip. Bzip2 uses a large amount of
+	  memory. For modern kernels you will need at least 8MB RAM or more for
+	  booting.
+
+	  If you choose this, keep in mind that you need to have the bzip2 tool
+	  available to be able to compress the initram.
+
+config INITRAMFS_COMPRESSION_LZMA
+	bool "LZMA"
+	depends on RD_LZMA
+	help
+	  This algorithm's compression ratio is best but has a large dictionary
+	  size which might cause issues in memory constrained systems.
+	  Decompression speed is between the other choices. Compression is
+	  slowest. The initramfs size is about 33% smaller with LZMA in
+	  comparison to gzip.
+
+	  If you choose this, keep in mind that you may need to install the xz
+	  or lzma tools to be able to compress the initram.
+
+config INITRAMFS_COMPRESSION_XZ
+	bool "XZ"
+	depends on RD_XZ
+	help
+	  XZ uses the LZMA2 algorithm and has a large dictionary which may cause
+	  problems on memory constrained systems. The initramfs size is about
+	  30% smaller with XZ in comparison to gzip. Decompression speed is
+	  better than that of bzip2 but worse than gzip and LZO. Compression is
+	  slow.
+
+	  If you choose this, keep in mind that you may need to install the xz
+	  tool to be able to compress the initram.
+
+config INITRAMFS_COMPRESSION_LZO
+	bool "LZO"
+	depends on RD_LZO
+	help
+	  It's compression ratio is the second poorest amongst the choices. The
+	  kernel size is about 10% bigger than gzip. Despite that, it's
+	  decompression speed is the second fastest and it's compression speed
+	  is quite fast too.
+
+	  If you choose this, keep in mind that you may need to install the lzop
+	  tool to be able to compress the initram.
+
+config INITRAMFS_COMPRESSION_LZ4
+	bool "LZ4"
+	depends on RD_LZ4
+	help
+	  It's compression ratio is the poorest amongst the choices. The kernel
+	  size is about 15% bigger than gzip; however its decompression speed
+	  is the fastest.
+
+	  If you choose this, keep in mind that most distros don't provide lz4
+	  by default which could cause a build failure.
+
+config INITRAMFS_COMPRESSION_NONE
+	bool "None"
+	help
+	  Do not compress the built-in initramfs at all. This may sound wasteful
+	  in space, but, you should be aware that the built-in initramfs will be
+	  compressed at a later stage anyways along with the rest of the kernel,
+	  on those architectures that support this. However, not compressing the
+	  initramfs may lead to slightly higher memory consumption during a
+	  short time at boot, while both the cpio image and the unpacked
+	  filesystem image will be present in memory simultaneously
+
+endchoice
+
+config INITRAMFS_COMPRESSION
+	depends on INITRAMFS_SOURCE!=""
+	string
+	default ""      if INITRAMFS_COMPRESSION_NONE
+	default ".gz"   if INITRAMFS_COMPRESSION_GZIP
+	default ".bz2"  if INITRAMFS_COMPRESSION_BZIP2
+	default ".lzma" if INITRAMFS_COMPRESSION_LZMA
+	default ".xz"   if INITRAMFS_COMPRESSION_XZ
+	default ".lzo"  if INITRAMFS_COMPRESSION_LZO
+	default ".lz4"  if INITRAMFS_COMPRESSION_LZ4
+	default ".gz"   if RD_GZIP
+	default ".lz4"  if RD_LZ4
+	default ".lzo"  if RD_LZO
+	default ".xz"   if RD_XZ
+	default ".lzma" if RD_LZMA
+	default ".bz2"  if RD_BZIP2
+	default ""

usr/Makefile

@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# kbuild file for usr/ - including initramfs image
+#
+
+klibcdirs:;
+PHONY += klibcdirs
+
+suffix_y = $(subst $\",,$(CONFIG_INITRAMFS_COMPRESSION))
+datafile_y = initramfs_data.cpio$(suffix_y)
+datafile_d_y = .$(datafile_y).d
+AFLAGS_initramfs_data.o += -DINITRAMFS_IMAGE="usr/$(datafile_y)"
+
+# clean rules do not have CONFIG_INITRAMFS_COMPRESSION.  So clean up after all
+# possible compression formats.
+clean-files += initramfs_data.cpio*
+
+# Generate builtin.o based on initramfs_data.o
+obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o
+
+# initramfs_data.o contains the compressed initramfs_data.cpio image.
+# The image is included using .incbin, a dependency which is not
+# tracked automatically.
+$(obj)/initramfs_data.o: $(obj)/$(datafile_y) FORCE
+
+#####
+# Generate the initramfs cpio archive
+
+hostprogs-y := gen_init_cpio
+initramfs   := $(CONFIG_SHELL) $(srctree)/$(src)/gen_initramfs_list.sh
+ramfs-input := $(if $(filter-out "",$(CONFIG_INITRAMFS_SOURCE)), \
+			$(shell echo $(CONFIG_INITRAMFS_SOURCE)),-d)
+ramfs-args  := \
+        $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
+        $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))
+
+# $(datafile_d_y) is used to identify all files included
+# in initramfs and to detect if any files are added/removed.
+# Removed files are identified by directory timestamp being updated
+# The dependency list is generated by gen_initramfs.sh -l
+ifneq ($(wildcard $(obj)/$(datafile_d_y)),)
+	include $(obj)/$(datafile_d_y)
+endif
+
+quiet_cmd_initfs = GEN     $@
+      cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)
+
+targets := $(datafile_y)
+
+# do not try to update files included in initramfs
+$(deps_initramfs): ;
+
+$(deps_initramfs): klibcdirs
+# We rebuild initramfs_data.cpio if:
+# 1) Any included file is newer then initramfs_data.cpio
+# 2) There are changes in which files are included (added or deleted)
+# 3) If gen_init_cpio are newer than initramfs_data.cpio
+# 4) arguments to gen_initramfs.sh changes
+$(obj)/$(datafile_y): $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs
+	$(Q)$(initramfs) -l $(ramfs-input) > $(obj)/$(datafile_d_y)
+	$(call if_changed,initfs)

usr/gen_init_cpio.c

@@ -0,0 +1,624 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <unistd.h>
+#include <time.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+
+/*
+ * Original work by Jeff Garzik
+ *
+ * External file lists, symlink, pipe and fifo support by Thayne Harbaugh
+ * Hard link support by Luciano Rocha
+ */
+
+#define xstr(s) #s
+#define str(s) xstr(s)
+
+static unsigned int offset;
+static unsigned int ino = 721;
+static time_t default_mtime;
+
+struct file_handler {
+	const char *type;
+	int (*handler)(const char *line);
+};
+
+static void push_string(const char *name)
+{
+	unsigned int name_len = strlen(name) + 1;
+
+	fputs(name, stdout);
+	putchar(0);
+	offset += name_len;
+}
+
+static void push_pad (void)
+{
+	while (offset & 3) {
+		putchar(0);
+		offset++;
+	}
+}
+
+static void push_rest(const char *name)
+{
+	unsigned int name_len = strlen(name) + 1;
+	unsigned int tmp_ofs;
+
+	fputs(name, stdout);
+	putchar(0);
+	offset += name_len;
+
+	tmp_ofs = name_len + 110;
+	while (tmp_ofs & 3) {
+		putchar(0);
+		offset++;
+		tmp_ofs++;
+	}
+}
+
+static void push_hdr(const char *s)
+{
+	fputs(s, stdout);
+	offset += 110;
+}
+
+static void cpio_trailer(void)
+{
+	char s[256];
+	const char name[] = "TRAILER!!!";
+
+	sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
+	       "%08X%08X%08X%08X%08X%08X%08X",
+		"070701",		/* magic */
+		0,			/* ino */
+		0,			/* mode */
+		(long) 0,		/* uid */
+		(long) 0,		/* gid */
+		1,			/* nlink */
+		(long) 0,		/* mtime */
+		0,			/* filesize */
+		0,			/* major */
+		0,			/* minor */
+		0,			/* rmajor */
+		0,			/* rminor */
+		(unsigned)strlen(name)+1, /* namesize */
+		0);			/* chksum */
+	push_hdr(s);
+	push_rest(name);
+
+	while (offset % 512) {
+		putchar(0);
+		offset++;
+	}
+}
+
+static int cpio_mkslink(const char *name, const char *target,
+			 unsigned int mode, uid_t uid, gid_t gid)
+{
+	char s[256];
+
+	if (name[0] == '/')
+		name++;
+	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
+	       "%08X%08X%08X%08X%08X%08X%08X",
+		"070701",		/* magic */
+		ino++,			/* ino */
+		S_IFLNK | mode,		/* mode */
+		(long) uid,		/* uid */
+		(long) gid,		/* gid */
+		1,			/* nlink */
+		(long) default_mtime,	/* mtime */
+		(unsigned)strlen(target)+1, /* filesize */
+		3,			/* major */
+		1,			/* minor */
+		0,			/* rmajor */
+		0,			/* rminor */
+		(unsigned)strlen(name) + 1,/* namesize */
+		0);			/* chksum */
+	push_hdr(s);
+	push_string(name);
+	push_pad();
+	push_string(target);
+	push_pad();
+	return 0;
+}
+
+static int cpio_mkslink_line(const char *line)
+{
+	char name[PATH_MAX + 1];
+	char target[PATH_MAX + 1];
+	unsigned int mode;
+	int uid;
+	int gid;
+	int rc = -1;
+
+	if (5 != sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX) "s %o %d %d", name, target, &mode, &uid, &gid)) {
+		fprintf(stderr, "Unrecognized dir format '%s'", line);
+		goto fail;
+	}
+	rc = cpio_mkslink(name, target, mode, uid, gid);
+ fail:
+	return rc;
+}
+
+static int cpio_mkgeneric(const char *name, unsigned int mode,
+		       uid_t uid, gid_t gid)
+{
+	char s[256];
+
+	if (name[0] == '/')
+		name++;
+	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
+	       "%08X%08X%08X%08X%08X%08X%08X",
+		"070701",		/* magic */
+		ino++,			/* ino */
+		mode,			/* mode */
+		(long) uid,		/* uid */
+		(long) gid,		/* gid */
+		2,			/* nlink */
+		(long) default_mtime,	/* mtime */
+		0,			/* filesize */
+		3,			/* major */
+		1,			/* minor */
+		0,			/* rmajor */
+		0,			/* rminor */
+		(unsigned)strlen(name) + 1,/* namesize */
+		0);			/* chksum */
+	push_hdr(s);
+	push_rest(name);
+	return 0;
+}
+
+enum generic_types {
+	GT_DIR,
+	GT_PIPE,
+	GT_SOCK
+};
+
+struct generic_type {
+	const char *type;
+	mode_t mode;
+};
+
+static struct generic_type generic_type_table[] = {
+	[GT_DIR] = {
+		.type = "dir",
+		.mode = S_IFDIR
+	},
+	[GT_PIPE] = {
+		.type = "pipe",
+		.mode = S_IFIFO
+	},
+	[GT_SOCK] = {
+		.type = "sock",
+		.mode = S_IFSOCK
+	}
+};
+
+static int cpio_mkgeneric_line(const char *line, enum generic_types gt)
+{
+	char name[PATH_MAX + 1];
+	unsigned int mode;
+	int uid;
+	int gid;
+	int rc = -1;
+
+	if (4 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d", name, &mode, &uid, &gid)) {
+		fprintf(stderr, "Unrecognized %s format '%s'",
+			line, generic_type_table[gt].type);
+		goto fail;
+	}
+	mode |= generic_type_table[gt].mode;
+	rc = cpio_mkgeneric(name, mode, uid, gid);
+ fail:
+	return rc;
+}
+
+static int cpio_mkdir_line(const char *line)
+{
+	return cpio_mkgeneric_line(line, GT_DIR);
+}
+
+static int cpio_mkpipe_line(const char *line)
+{
+	return cpio_mkgeneric_line(line, GT_PIPE);
+}
+
+static int cpio_mksock_line(const char *line)
+{
+	return cpio_mkgeneric_line(line, GT_SOCK);
+}
+
+static int cpio_mknod(const char *name, unsigned int mode,
+		       uid_t uid, gid_t gid, char dev_type,
+		       unsigned int maj, unsigned int min)
+{
+	char s[256];
+
+	if (dev_type == 'b')
+		mode |= S_IFBLK;
+	else
+		mode |= S_IFCHR;
+
+	if (name[0] == '/')
+		name++;
+	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
+	       "%08X%08X%08X%08X%08X%08X%08X",
+		"070701",		/* magic */
+		ino++,			/* ino */
+		mode,			/* mode */
+		(long) uid,		/* uid */
+		(long) gid,		/* gid */
+		1,			/* nlink */
+		(long) default_mtime,	/* mtime */
+		0,			/* filesize */
+		3,			/* major */
+		1,			/* minor */
+		maj,			/* rmajor */
+		min,			/* rminor */
+		(unsigned)strlen(name) + 1,/* namesize */
+		0);			/* chksum */
+	push_hdr(s);
+	push_rest(name);
+	return 0;
+}
+
+static int cpio_mknod_line(const char *line)
+{
+	char name[PATH_MAX + 1];
+	unsigned int mode;
+	int uid;
+	int gid;
+	char dev_type;
+	unsigned int maj;
+	unsigned int min;
+	int rc = -1;
+
+	if (7 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d %c %u %u",
+			 name, &mode, &uid, &gid, &dev_type, &maj, &min)) {
+		fprintf(stderr, "Unrecognized nod format '%s'", line);
+		goto fail;
+	}
+	rc = cpio_mknod(name, mode, uid, gid, dev_type, maj, min);
+ fail:
+	return rc;
+}
+
+static int cpio_mkfile(const char *name, const char *location,
+			unsigned int mode, uid_t uid, gid_t gid,
+			unsigned int nlinks)
+{
+	char s[256];
+	char *filebuf = NULL;
+	struct stat buf;
+	long size;
+	int file = -1;
+	int retval;
+	int rc = -1;
+	int namesize;
+	unsigned int i;
+
+	mode |= S_IFREG;
+
+	file = open (location, O_RDONLY);
+	if (file < 0) {
+		fprintf (stderr, "File %s could not be opened for reading\n", location);
+		goto error;
+	}
+
+	retval = fstat(file, &buf);
+	if (retval) {
+		fprintf(stderr, "File %s could not be stat()'ed\n", location);
+		goto error;
+	}
+
+	filebuf = malloc(buf.st_size);
+	if (!filebuf) {
+		fprintf (stderr, "out of memory\n");
+		goto error;
+	}
+
+	retval = read (file, filebuf, buf.st_size);
+	if (retval < 0) {
+		fprintf (stderr, "Can not read %s file\n", location);
+		goto error;
+	}
+
+	size = 0;
+	for (i = 1; i <= nlinks; i++) {
+		/* data goes on last link */
+		if (i == nlinks) size = buf.st_size;
+
+		if (name[0] == '/')
+			name++;
+		namesize = strlen(name) + 1;
+		sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
+		       "%08lX%08X%08X%08X%08X%08X%08X",
+			"070701",		/* magic */
+			ino,			/* ino */
+			mode,			/* mode */
+			(long) uid,		/* uid */
+			(long) gid,		/* gid */
+			nlinks,			/* nlink */
+			(long) buf.st_mtime,	/* mtime */
+			size,			/* filesize */
+			3,			/* major */
+			1,			/* minor */
+			0,			/* rmajor */
+			0,			/* rminor */
+			namesize,		/* namesize */
+			0);			/* chksum */
+		push_hdr(s);
+		push_string(name);
+		push_pad();
+
+		if (size) {
+			if (fwrite(filebuf, size, 1, stdout) != 1) {
+				fprintf(stderr, "writing filebuf failed\n");
+				goto error;
+			}
+			offset += size;
+			push_pad();
+		}
+
+		name += namesize;
+	}
+	ino++;
+	rc = 0;
+	
+error:
+	if (filebuf) free(filebuf);
+	if (file >= 0) close(file);
+	return rc;
+}
+
+static char *cpio_replace_env(char *new_location)
+{
+	char expanded[PATH_MAX + 1];
+	char *start, *end, *var;
+
+	while ((start = strstr(new_location, "${")) &&
+	       (end = strchr(start + 2, '}'))) {
+		*start = *end = 0;
+		var = getenv(start + 2);
+		snprintf(expanded, sizeof expanded, "%s%s%s",
+			 new_location, var ? var : "", end + 1);
+		strcpy(new_location, expanded);
+	}
+
+	return new_location;
+}
+
+static int cpio_mkfile_line(const char *line)
+{
+	char name[PATH_MAX + 1];
+	char *dname = NULL; /* malloc'ed buffer for hard links */
+	char location[PATH_MAX + 1];
+	unsigned int mode;
+	int uid;
+	int gid;
+	int nlinks = 1;
+	int end = 0, dname_len = 0;
+	int rc = -1;
+
+	if (5 > sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX)
+				"s %o %d %d %n",
+				name, location, &mode, &uid, &gid, &end)) {
+		fprintf(stderr, "Unrecognized file format '%s'", line);
+		goto fail;
+	}
+	if (end && isgraph(line[end])) {
+		int len;
+		int nend;
+
+		dname = malloc(strlen(line));
+		if (!dname) {
+			fprintf (stderr, "out of memory (%d)\n", dname_len);
+			goto fail;
+		}
+
+		dname_len = strlen(name) + 1;
+		memcpy(dname, name, dname_len);
+
+		do {
+			nend = 0;
+			if (sscanf(line + end, "%" str(PATH_MAX) "s %n",
+					name, &nend) < 1)
+				break;
+			len = strlen(name) + 1;
+			memcpy(dname + dname_len, name, len);
+			dname_len += len;
+			nlinks++;
+			end += nend;
+		} while (isgraph(line[end]));
+	} else {
+		dname = name;
+	}
+	rc = cpio_mkfile(dname, cpio_replace_env(location),
+	                 mode, uid, gid, nlinks);
+ fail:
+	if (dname_len) free(dname);
+	return rc;
+}
+
+static void usage(const char *prog)
+{
+	fprintf(stderr, "Usage:\n"
+		"\t%s [-t <timestamp>] <cpio_list>\n"
+		"\n"
+		"<cpio_list> is a file containing newline separated entries that\n"
+		"describe the files to be included in the initramfs archive:\n"
+		"\n"
+		"# a comment\n"
+		"file <name> <location> <mode> <uid> <gid> [<hard links>]\n"
+		"dir <name> <mode> <uid> <gid>\n"
+		"nod <name> <mode> <uid> <gid> <dev_type> <maj> <min>\n"
+		"slink <name> <target> <mode> <uid> <gid>\n"
+		"pipe <name> <mode> <uid> <gid>\n"
+		"sock <name> <mode> <uid> <gid>\n"
+		"\n"
+		"<name>       name of the file/dir/nod/etc in the archive\n"
+		"<location>   location of the file in the current filesystem\n"
+		"             expands shell variables quoted with ${}\n"
+		"<target>     link target\n"
+		"<mode>       mode/permissions of the file\n"
+		"<uid>        user id (0=root)\n"
+		"<gid>        group id (0=root)\n"
+		"<dev_type>   device type (b=block, c=character)\n"
+		"<maj>        major number of nod\n"
+		"<min>        minor number of nod\n"
+		"<hard links> space separated list of other links to file\n"
+		"\n"
+		"example:\n"
+		"# A simple initramfs\n"
+		"dir /dev 0755 0 0\n"
+		"nod /dev/console 0600 0 0 c 5 1\n"
+		"dir /root 0700 0 0\n"
+		"dir /sbin 0755 0 0\n"
+		"file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0\n"
+		"\n"
+		"<timestamp> is time in seconds since Epoch that will be used\n"
+		"as mtime for symlinks, special files and directories. The default\n"
+		"is to use the current time for these entries.\n",
+		prog);
+}
+
+struct file_handler file_handler_table[] = {
+	{
+		.type    = "file",
+		.handler = cpio_mkfile_line,
+	}, {
+		.type    = "nod",
+		.handler = cpio_mknod_line,
+	}, {
+		.type    = "dir",
+		.handler = cpio_mkdir_line,
+	}, {
+		.type    = "slink",
+		.handler = cpio_mkslink_line,
+	}, {
+		.type    = "pipe",
+		.handler = cpio_mkpipe_line,
+	}, {
+		.type    = "sock",
+		.handler = cpio_mksock_line,
+	}, {
+		.type    = NULL,
+		.handler = NULL,
+	}
+};
+
+#define LINE_SIZE (2 * PATH_MAX + 50)
+
+int main (int argc, char *argv[])
+{
+	FILE *cpio_list;
+	char line[LINE_SIZE];
+	char *args, *type;
+	int ec = 0;
+	int line_nr = 0;
+	const char *filename;
+
+	default_mtime = time(NULL);
+	while (1) {
+		int opt = getopt(argc, argv, "t:h");
+		char *invalid;
+
+		if (opt == -1)
+			break;
+		switch (opt) {
+		case 't':
+			default_mtime = strtol(optarg, &invalid, 10);
+			if (!*optarg || *invalid) {
+				fprintf(stderr, "Invalid timestamp: %s\n",
+						optarg);
+				usage(argv[0]);
+				exit(1);
+			}
+			break;
+		case 'h':
+		case '?':
+			usage(argv[0]);
+			exit(opt == 'h' ? 0 : 1);
+		}
+	}
+
+	if (argc - optind != 1) {
+		usage(argv[0]);
+		exit(1);
+	}
+	filename = argv[optind];
+	if (!strcmp(filename, "-"))
+		cpio_list = stdin;
+	else if (!(cpio_list = fopen(filename, "r"))) {
+		fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
+			filename, strerror(errno));
+		usage(argv[0]);
+		exit(1);
+	}
+
+	while (fgets(line, LINE_SIZE, cpio_list)) {
+		int type_idx;
+		size_t slen = strlen(line);
+
+		line_nr++;
+
+		if ('#' == *line) {
+			/* comment - skip to next line */
+			continue;
+		}
+
+		if (! (type = strtok(line, " \t"))) {
+			fprintf(stderr,
+				"ERROR: incorrect format, could not locate file type line %d: '%s'\n",
+				line_nr, line);
+			ec = -1;
+			break;
+		}
+
+		if ('\n' == *type) {
+			/* a blank line */
+			continue;
+		}
+
+		if (slen == strlen(type)) {
+			/* must be an empty line */
+			continue;
+		}
+
+		if (! (args = strtok(NULL, "\n"))) {
+			fprintf(stderr,
+				"ERROR: incorrect format, newline required line %d: '%s'\n",
+				line_nr, line);
+			ec = -1;
+		}
+
+		for (type_idx = 0; file_handler_table[type_idx].type; type_idx++) {
+			int rc;
+			if (! strcmp(line, file_handler_table[type_idx].type)) {
+				if ((rc = file_handler_table[type_idx].handler(args))) {
+					ec = rc;
+					fprintf(stderr, " line %d\n", line_nr);
+				}
+				break;
+			}
+		}
+
+		if (NULL == file_handler_table[type_idx].type) {
+			fprintf(stderr, "unknown file type line %d: '%s'\n",
+				line_nr, line);
+		}
+	}
+	if (ec == 0)
+		cpio_trailer();
+
+	exit(ec);
+}

usr/gen_initramfs_list.sh

@@ -0,0 +1,328 @@
+#!/bin/sh
+# Copyright (C) Martin Schlemmer <azarah@nosferatu.za.org>
+# Copyright (C) 2006 Sam Ravnborg <sam@ravnborg.org>
+#
+# Released under the terms of the GNU GPL
+#
+# Generate a cpio packed initramfs. It uses gen_init_cpio to generate
+# the cpio archive, and then compresses it.
+# The script may also be used to generate the inputfile used for gen_init_cpio
+# This script assumes that gen_init_cpio is located in usr/ directory
+
+# error out on errors
+set -e
+
+usage() {
+cat << EOF
+Usage:
+$0 [-o <file>] [-u <uid>] [-g <gid>] {-d | <cpio_source>} ...
+	-o <file>      Create compressed initramfs file named <file> using
+		       gen_init_cpio and compressor depending on the extension
+	-u <uid>       User ID to map to user ID 0 (root).
+		       <uid> is only meaningful if <cpio_source> is a
+		       directory.  "squash" forces all files to uid 0.
+	-g <gid>       Group ID to map to group ID 0 (root).
+		       <gid> is only meaningful if <cpio_source> is a
+		       directory.  "squash" forces all files to gid 0.
+	<cpio_source>  File list or directory for cpio archive.
+		       If <cpio_source> is a .cpio file it will be used
+		       as direct input to initramfs.
+	-d             Output the default cpio list.
+
+All options except -o and -l may be repeated and are interpreted
+sequentially and immediately.  -u and -g states are preserved across
+<cpio_source> options so an explicit "-u 0 -g 0" is required
+to reset the root/group mapping.
+EOF
+}
+
+# awk style field access
+# $1 - field number; rest is argument string
+field() {
+	shift $1 ; echo $1
+}
+
+list_default_initramfs() {
+	# echo usr/kinit/kinit
+	:
+}
+
+default_initramfs() {
+	cat <<-EOF >> ${output}
+		# This is a very simple, default initramfs
+
+		dir /dev 0755 0 0
+		nod /dev/console 0600 0 0 c 5 1
+		dir /root 0700 0 0
+		# file /kinit usr/kinit/kinit 0755 0 0
+		# slink /init kinit 0755 0 0
+	EOF
+}
+
+filetype() {
+	local argv1="$1"
+
+	# symlink test must come before file test
+	if [ -L "${argv1}" ]; then
+		echo "slink"
+	elif [ -f "${argv1}" ]; then
+		echo "file"
+	elif [ -d "${argv1}" ]; then
+		echo "dir"
+	elif [ -b "${argv1}" -o -c "${argv1}" ]; then
+		echo "nod"
+	elif [ -p "${argv1}" ]; then
+		echo "pipe"
+	elif [ -S "${argv1}" ]; then
+		echo "sock"
+	else
+		echo "invalid"
+	fi
+	return 0
+}
+
+list_print_mtime() {
+	:
+}
+
+print_mtime() {
+	local my_mtime="0"
+
+	if [ -e "$1" ]; then
+		my_mtime=$(find "$1" -printf "%T@\n" | sort -r | head -n 1)
+	fi
+
+	echo "# Last modified: ${my_mtime}" >> ${output}
+	echo "" >> ${output}
+}
+
+list_parse() {
+	if [ -L "$1" ]; then
+		return
+	fi
+	echo "$1" | sed 's/:/\\:/g; s/$/ \\/'
+}
+
+# for each file print a line in following format
+# <filetype> <name> <path to file> <octal mode> <uid> <gid>
+# for links, devices etc the format differs. See gen_init_cpio for details
+parse() {
+	local location="$1"
+	local name="/${location#${srcdir}}"
+	# change '//' into '/'
+	name=$(echo "$name" | sed -e 's://*:/:g')
+	local mode="$2"
+	local uid="$3"
+	local gid="$4"
+	local ftype=$(filetype "${location}")
+	# remap uid/gid to 0 if necessary
+	[ "$root_uid" = "squash" ] && uid=0 || [ "$uid" -eq "$root_uid" ] && uid=0
+	[ "$root_gid" = "squash" ] && gid=0 || [ "$gid" -eq "$root_gid" ] && gid=0
+	local str="${mode} ${uid} ${gid}"
+
+	[ "${ftype}" = "invalid" ] && return 0
+	[ "${location}" = "${srcdir}" ] && return 0
+
+	case "${ftype}" in
+		"file")
+			str="${ftype} ${name} ${location} ${str}"
+			;;
+		"nod")
+			local dev=`LC_ALL=C ls -l "${location}"`
+			local maj=`field 5 ${dev}`
+			local min=`field 6 ${dev}`
+			maj=${maj%,}
+
+			[ -b "${location}" ] && dev="b" || dev="c"
+
+			str="${ftype} ${name} ${str} ${dev} ${maj} ${min}"
+			;;
+		"slink")
+			local target=`readlink "${location}"`
+			str="${ftype} ${name} ${target} ${str}"
+			;;
+		*)
+			str="${ftype} ${name} ${str}"
+			;;
+	esac
+
+	echo "${str}" >> ${output}
+
+	return 0
+}
+
+unknown_option() {
+	printf "ERROR: unknown option \"$arg\"\n" >&2
+	printf "If the filename validly begins with '-', " >&2
+	printf "then it must be prefixed\n" >&2
+	printf "by './' so that it won't be interpreted as an option." >&2
+	printf "\n" >&2
+	usage >&2
+	exit 1
+}
+
+list_header() {
+	:
+}
+
+header() {
+	printf "\n#####################\n# $1\n" >> ${output}
+}
+
+# process one directory (incl sub-directories)
+dir_filelist() {
+	${dep_list}header "$1"
+
+	srcdir=$(echo "$1" | sed -e 's://*:/:g')
+	dirlist=$(find "${srcdir}" -printf "%p %m %U %G\n" | LANG=C sort)
+
+	# If $dirlist is only one line, then the directory is empty
+	if [  "$(echo "${dirlist}" | wc -l)" -gt 1 ]; then
+		${dep_list}print_mtime "$1"
+
+		echo "${dirlist}" | \
+		while read x; do
+			${dep_list}parse ${x}
+		done
+	fi
+}
+
+# if only one file is specified and it is .cpio file then use it direct as fs
+# if a directory is specified then add all files in given direcotry to fs
+# if a regular file is specified assume it is in gen_initramfs format
+input_file() {
+	source="$1"
+	if [ -f "$1" ]; then
+		${dep_list}header "$1"
+		is_cpio="$(echo "$1" | sed 's/^.*\.cpio\(\..*\)\{0,1\}/cpio/')"
+		if [ $2 -eq 0 -a ${is_cpio} = "cpio" ]; then
+			cpio_file=$1
+			echo "$1" | grep -q '^.*\.cpio\..*' && is_cpio_compressed="compressed"
+			[ ! -z ${dep_list} ] && echo "$1"
+			return 0
+		fi
+		if [ -z ${dep_list} ]; then
+			print_mtime "$1" >> ${output}
+			cat "$1"         >> ${output}
+		else
+		        echo "$1 \\"
+			cat "$1" | while read type dir file perm ; do
+				if [ "$type" = "file" ]; then
+					echo "$file \\";
+				fi
+			done
+		fi
+	elif [ -d "$1" ]; then
+		dir_filelist "$1"
+	else
+		echo "  ${prog}: Cannot open '$1'" >&2
+		exit 1
+	fi
+}
+
+prog=$0
+root_uid=0
+root_gid=0
+dep_list=
+cpio_file=
+cpio_list=
+output="/dev/stdout"
+output_file=""
+is_cpio_compressed=
+compr="gzip -n -9 -f"
+
+arg="$1"
+case "$arg" in
+	"-l")	# files included in initramfs - used by kbuild
+		dep_list="list_"
+		echo "deps_initramfs := $0 \\"
+		shift
+		;;
+	"-o")	# generate compressed cpio image named $1
+		shift
+		output_file="$1"
+		cpio_list="$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX)"
+		output=${cpio_list}
+		echo "$output_file" | grep -q "\.gz$" \
+                && [ -x "`which gzip 2> /dev/null`" ] \
+                && compr="gzip -n -9 -f"
+		echo "$output_file" | grep -q "\.bz2$" \
+                && [ -x "`which bzip2 2> /dev/null`" ] \
+                && compr="bzip2 -9 -f"
+		echo "$output_file" | grep -q "\.lzma$" \
+                && [ -x "`which lzma 2> /dev/null`" ] \
+                && compr="lzma -9 -f"
+		echo "$output_file" | grep -q "\.xz$" \
+                && [ -x "`which xz 2> /dev/null`" ] \
+                && compr="xz --check=crc32 --lzma2=dict=1MiB"
+		echo "$output_file" | grep -q "\.lzo$" \
+                && [ -x "`which lzop 2> /dev/null`" ] \
+                && compr="lzop -9 -f"
+		echo "$output_file" | grep -q "\.lz4$" \
+                && [ -x "`which lz4 2> /dev/null`" ] \
+                && compr="lz4 -l -9 -f"
+		echo "$output_file" | grep -q "\.cpio$" && compr="cat"
+		shift
+		;;
+esac
+while [ $# -gt 0 ]; do
+	arg="$1"
+	shift
+	case "$arg" in
+		"-u")	# map $1 to uid=0 (root)
+			root_uid="$1"
+			[ "$root_uid" = "-1" ] && root_uid=$(id -u || echo 0)
+			shift
+			;;
+		"-g")	# map $1 to gid=0 (root)
+			root_gid="$1"
+			[ "$root_gid" = "-1" ] && root_gid=$(id -g || echo 0)
+			shift
+			;;
+		"-d")	# display default initramfs list
+			default_list="$arg"
+			${dep_list}default_initramfs
+			;;
+		"-h")
+			usage
+			exit 0
+			;;
+		*)
+			case "$arg" in
+				"-"*)
+					unknown_option
+					;;
+				*)	# input file/dir - process it
+					input_file "$arg" "$#"
+					;;
+			esac
+			;;
+	esac
+done
+
+# If output_file is set we will generate cpio archive and compress it
+# we are careful to delete tmp files
+if [ ! -z ${output_file} ]; then
+	if [ -z ${cpio_file} ]; then
+		timestamp=
+		if test -n "$KBUILD_BUILD_TIMESTAMP"; then
+			timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)"
+			if test -n "$timestamp"; then
+				timestamp="-t $timestamp"
+			fi
+		fi
+		cpio_tfile="$(mktemp ${TMPDIR:-/tmp}/cpiofile.XXXXXX)"
+		usr/gen_init_cpio $timestamp ${cpio_list} > ${cpio_tfile}
+	else
+		cpio_tfile=${cpio_file}
+	fi
+	rm ${cpio_list}
+	if [ "${is_cpio_compressed}" = "compressed" ]; then
+		cat ${cpio_tfile} > ${output_file}
+	else
+		(cat ${cpio_tfile} | ${compr}  - > ${output_file}) \
+		|| (rm -f ${output_file} ; false)
+	fi
+	[ -z ${cpio_file} ] && rm ${cpio_tfile}
+fi
+exit 0

usr/initramfs_data.S

@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+  initramfs_data includes the compressed binary that is the
+  filesystem used for early user space.
+  Note: Older versions of "as" (prior to binutils 2.11.90.0.23
+  released on 2001-07-14) dit not support .incbin.
+  If you are forced to use older binutils than that then the
+  following trick can be applied to create the resulting binary:
+
+
+  ld -m elf_i386  --format binary --oformat elf32-i386 -r \
+  -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o
+   ld -m elf_i386  -r -o built-in.a initramfs_data.o
+
+  For including the .init.ramfs sections, see include/asm-generic/vmlinux.lds.
+
+  The above example is for i386 - the parameters vary from architectures.
+  Eventually look up LDFLAGS_BLOB in an older version of the
+  arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced.
+
+  Using .incbin has the advantage over ld that the correct flags are set
+  in the ELF header, as required by certain architectures.
+*/
+
+#include <linux/stringify.h>
+#include <asm-generic/vmlinux.lds.h>
+
+.section .init.ramfs,"a"
+__irf_start:
+.incbin __stringify(INITRAMFS_IMAGE)
+__irf_end:
+.section .init.ramfs.info,"a"
+.globl __initramfs_size
+__initramfs_size:
+#ifdef CONFIG_64BIT
+	.quad __irf_end - __irf_start
+#else
+	.long __irf_end - __irf_start
+#endif