Adding upstream version 2.39.3.upstream/2.39.3

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 943 insertions, 0 deletions

diff --git a/disk-utils/mkfs.cramfs.c b/disk-utils/mkfs.cramfs.c
new file mode 100644
index 0000000..fcc1314
--- /dev/null
+++ b/disk-utils/mkfs.cramfs.c
@@ -0,0 +1,943 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * mkcramfs - make a cramfs file system
+ *
+ * Copyright (C) 1999-2002 Transmeta Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * Old version would die on largish filesystems. Change to mmap the
+ * files one by one instead of all simultaneously. - aeb, 2002-11-01
+ */
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <getopt.h>
+#include <zconf.h>
+
+/* We don't use our include/crc32.h, but crc32 from zlib!
+ *
+ * The zlib implementation performs pre/post-conditioning. The util-linux
+ * imlemenation requires post-conditioning (xor) in the applications.
+ */
+#include <zlib.h>
+
+#include "blkdev.h"
+#include "c.h"
+#include "cramfs.h"
+#include "md5.h"
+#include "nls.h"
+#include "exitcodes.h"
+#include "strutils.h"
+
+#define CLOSE_EXIT_CODE	 MKFS_EX_ERROR
+#include "closestream.h"
+
+#define XALLOC_EXIT_CODE MKFS_EX_ERROR
+#include "xalloc.h"
+
+/* The kernel only supports PAD_SIZE of 0 and 512. */
+#define PAD_SIZE 512
+
+static int verbose = 0;
+
+static unsigned int blksize = 0; /* settable via -b option, default page size */
+static long total_blocks = 0, total_nodes = 1; /* pre-count the root node */
+static int image_length = 0;
+static int cramfs_is_big_endian = 0; /* target is big endian */
+
+/*
+ * If opt_holes is set, then mkcramfs can create explicit holes in the
+ * data, which saves 26 bytes per hole (which is a lot smaller a
+ * saving than for most filesystems).
+ *
+ * Note that kernels up to at least 2.3.39 don't support cramfs holes,
+ * which is why this is turned off by default.
+ */
+static unsigned int opt_edition = 0;
+static int opt_errors = 0;
+static int opt_holes = 0;
+static int opt_pad = 0;
+static char *opt_image = NULL;
+static char *opt_name = NULL;
+
+static int warn_dev = 0;
+static int warn_gid = 0;
+static int warn_namelen = 0;
+static int warn_skip = 0;
+static int warn_size = 0;
+static int warn_uid = 0;
+
+/* entry.flags */
+#define CRAMFS_EFLAG_MD5	1
+#define CRAMFS_EFLAG_INVALID	2
+
+/* In-core version of inode / directory entry. */
+struct entry {
+	/* stats */
+	unsigned char *name;
+	unsigned int mode, size, uid, gid;
+	unsigned char md5sum[UL_MD5LENGTH];
+	unsigned char flags;	   /* CRAMFS_EFLAG_* */
+
+	/* FS data */
+	char *path;
+	int fd;			    /* temporarily open files while mmapped */
+	struct entry *same;	    /* points to other identical file */
+	unsigned int offset;        /* pointer to compressed data in archive */
+	unsigned int dir_offset;    /* offset of directory entry in archive */
+
+	/* organization */
+	struct entry *child;	    /* NULL for non-directory and empty dir */
+	struct entry *next;
+};
+
+/*
+ * Width of various bitfields in struct cramfs_inode.
+ * Used only to generate warnings.
+ */
+#define CRAMFS_SIZE_WIDTH 24
+#define CRAMFS_UID_WIDTH 16
+#define CRAMFS_GID_WIDTH 8
+#define CRAMFS_OFFSET_WIDTH 26
+
+static void __attribute__((__noreturn__)) usage(void)
+{
+	fputs(USAGE_HEADER, stdout);
+	printf(_(" %s [-h] [-v] [-b blksize] [-e edition] [-N endian] [-i file] [-n name] dirname outfile\n"),
+		program_invocation_short_name);
+	fputs(USAGE_SEPARATOR, stdout);
+	puts(_("Make compressed ROM file system."));
+	fputs(USAGE_OPTIONS, stdout);
+	puts(_(  " -v             be verbose"));
+	puts(_(  " -E             make all warnings errors (non-zero exit status)"));
+	puts(_(  " -b blksize     use this blocksize, must equal page size"));
+	puts(_(  " -e edition     set edition number (part of fsid)"));
+	printf(_(" -N endian      set cramfs endianness (%s|%s|%s), default %s\n"), "big", "little", "host", "host");
+	puts(_(  " -i file        insert a file image into the filesystem"));
+	puts(_(  " -n name        set name of cramfs filesystem"));
+	printf(_(" -p             pad by %d bytes for boot code\n"), PAD_SIZE);
+	puts(_(  " -s             sort directory entries (old option, ignored)"));
+	puts(_(  " -z             make explicit holes"));
+	puts(_(  " -l[=<mode>]    use exclusive device lock (yes, no or nonblock)"));
+	puts(_(  " dirname        root of the filesystem to be compressed"));
+	puts(_(  " outfile        output file"));
+	fputs(USAGE_SEPARATOR, stdout);
+	printf(USAGE_HELP_OPTIONS(16));
+	printf(USAGE_MAN_TAIL("mkfs.cramfs(8)"));
+	exit(MKFS_EX_OK);
+}
+
+static char *
+do_mmap(char *path, unsigned int size, unsigned int mode){
+	int fd;
+	char *start = NULL;
+
+	if (!size)
+		return NULL;
+
+	if (S_ISLNK(mode)) {
+		/* The link buffer is unnecessary to terminate by null as it's
+		 * always used as buffer rather than a string */
+		start = xmalloc(size);
+		if (readlink(path, start, size) < 0) {
+			warn(_("readlink failed: %s"), path);
+			warn_skip = 1;
+			goto err;
+		}
+		return start;
+	}
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		warn(_("cannot open %s"), path);
+		warn_skip = 1;
+		goto err;
+	}
+
+	start = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+	close(fd);
+	if (start == MAP_FAILED)
+		err(MKFS_EX_ERROR, "mmap");
+	return start;
+err:
+	free(start);
+	return NULL;
+}
+
+static void
+do_munmap(char *start, unsigned int size, unsigned int mode){
+	if (S_ISLNK(mode))
+		free(start);
+	else
+		munmap(start, size);
+}
+
+/* compute md5sums, so that we do not have to compare every pair of files */
+static void
+mdfile(struct entry *e) {
+	char *start;
+
+	start = do_mmap(e->path, e->size, e->mode);
+	if (start == NULL) {
+		e->flags |= CRAMFS_EFLAG_INVALID;
+	} else {
+		UL_MD5_CTX ctx;
+
+		ul_MD5Init(&ctx);
+		ul_MD5Update(&ctx, (unsigned char *) start, e->size);
+		ul_MD5Final(e->md5sum, &ctx);
+
+		do_munmap(start, e->size, e->mode);
+
+		e->flags |= CRAMFS_EFLAG_MD5;
+	}
+}
+
+/* md5 digests are equal; files are almost certainly the same,
+   but just to be sure, do the comparison */
+static int
+identical_file(struct entry *e1, struct entry *e2){
+	char *start1, *start2;
+	int equal;
+
+	start1 = do_mmap(e1->path, e1->size, e1->mode);
+	if (!start1)
+		return 0;
+	start2 = do_mmap(e2->path, e2->size, e2->mode);
+	if (!start2) {
+		do_munmap(start1, e1->size, e1->mode);
+		return 0;
+	}
+	equal = !memcmp(start1, start2, e1->size);
+	do_munmap(start1, e1->size, e1->mode);
+	do_munmap(start2, e2->size, e2->mode);
+	return equal;
+}
+
+/*
+ * The longest file name component to allow for in the input directory tree.
+ * Ext2fs (and many others) allow up to 255 bytes.  A couple of filesystems
+ * allow longer (e.g. smbfs 1024), but there isn't much use in supporting
+ * >255-byte names in the input directory tree given that such names get
+ * truncated to 255 bytes when written to cramfs.
+ */
+#define MAX_INPUT_NAMELEN 255
+
+static int find_identical_file(struct entry *orig, struct entry *new, loff_t *fslen_ub)
+{
+	if (orig == new)
+		return 1;
+	if (!orig)
+		return 0;
+	if (orig->size == new->size && orig->path) {
+		if (!orig->flags)
+			mdfile(orig);
+		if (!new->flags)
+			mdfile(new);
+
+		if ((orig->flags & CRAMFS_EFLAG_MD5) &&
+		    (new->flags & CRAMFS_EFLAG_MD5) &&
+		    !memcmp(orig->md5sum, new->md5sum, UL_MD5LENGTH) &&
+		    identical_file(orig, new)) {
+			new->same = orig;
+			*fslen_ub -= new->size;
+			return 1;
+		}
+	}
+	return find_identical_file(orig->child, new, fslen_ub) ||
+		   find_identical_file(orig->next, new, fslen_ub);
+}
+
+static void eliminate_doubles(struct entry *root, struct entry *orig, loff_t *fslen_ub) {
+	if (orig) {
+		if (orig->size && orig->path)
+			find_identical_file(root,orig, fslen_ub);
+		eliminate_doubles(root,orig->child, fslen_ub);
+		eliminate_doubles(root,orig->next, fslen_ub);
+	}
+}
+
+/*
+ * We define our own sorting function instead of using alphasort which
+ * uses strcoll and changes ordering based on locale information.
+ */
+static int cramsort (const struct dirent **a, const struct dirent **b)
+{
+	return strcmp((*a)->d_name, (*b)->d_name);
+}
+
+static unsigned int parse_directory(struct entry *root_entry, const char *name, struct entry **prev, loff_t *fslen_ub)
+{
+	struct dirent **dirlist;
+	int totalsize = 0, dircount, dirindex;
+	char *path, *endpath;
+	size_t len = strlen(name);
+
+	/* Set up the path. */
+	/* TODO: Reuse the parent's buffer to save memcpy'ing and duplication. */
+	path = xmalloc(len + 1 + MAX_INPUT_NAMELEN + 1);
+	memcpy(path, name, len);
+	endpath = path + len;
+	*endpath = '/';
+	endpath++;
+
+	/* read in the directory and sort */
+	dircount = scandir(name, &dirlist, NULL, cramsort);
+
+	if (dircount < 0)
+		err(MKFS_EX_ERROR, _("could not read directory %s"), name);
+
+	/* process directory */
+	for (dirindex = 0; dirindex < dircount; dirindex++) {
+		struct dirent *dirent;
+		struct entry *entry;
+		struct stat st;
+		int size;
+		size_t namelen;
+
+		dirent = dirlist[dirindex];
+
+		/* Ignore "." and ".." - we won't be adding them
+		   to the archive */
+		if (dirent->d_name[0] == '.') {
+			if (dirent->d_name[1] == '\0')
+				continue;
+			if (dirent->d_name[1] == '.' &&
+			    dirent->d_name[2] == '\0')
+				continue;
+		}
+		namelen = strlen(dirent->d_name);
+		if (namelen > MAX_INPUT_NAMELEN) {
+			namelen = MAX_INPUT_NAMELEN;
+			warn_namelen = 1;
+		}
+
+		memcpy(endpath, dirent->d_name, namelen + 1);
+
+		if (lstat(path, &st) < 0) {
+			warn(_("stat of %s failed"), endpath);
+			warn_skip = 1;
+			continue;
+		}
+		entry = xcalloc(1, sizeof(struct entry));
+		entry->name = (unsigned char *)xstrndup(dirent->d_name, namelen);
+		entry->mode = st.st_mode;
+		entry->size = st.st_size;
+		entry->uid = st.st_uid;
+		if (entry->uid >= 1 << CRAMFS_UID_WIDTH)
+			warn_uid = 1;
+		entry->gid = st.st_gid;
+		if (entry->gid >= 1 << CRAMFS_GID_WIDTH)
+			/* TODO: We ought to replace with a default
+			   gid instead of truncating; otherwise there
+			   are security problems.  Maybe mode should
+			   be &= ~070.  Same goes for uid once Linux
+			   supports >16-bit uids. */
+			warn_gid = 1;
+		size = sizeof(struct cramfs_inode) + ((namelen + 3) & ~3);
+		*fslen_ub += size;
+		if (S_ISDIR(st.st_mode)) {
+			entry->size = parse_directory(root_entry, path, &entry->child, fslen_ub);
+		} else if (S_ISREG(st.st_mode)) {
+			entry->path = xstrdup(path);
+			if (entry->size >= (1 << CRAMFS_SIZE_WIDTH)) {
+				warn_size = 1;
+				entry->size = (1 << CRAMFS_SIZE_WIDTH) - 1;
+			}
+		} else if (S_ISLNK(st.st_mode)) {
+			entry->path = xstrdup(path);
+		} else if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode)) {
+			/* maybe we should skip sockets */
+			entry->size = 0;
+		} else {
+			entry->size = st.st_rdev;
+			if (entry->size & -(1<<CRAMFS_SIZE_WIDTH))
+				warn_dev = 1;
+		}
+
+		if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
+			int blocks = ((entry->size - 1) / blksize + 1);
+
+			/* block pointers & data expansion allowance + data */
+			if (entry->size)
+				*fslen_ub += (4+26)*blocks + entry->size + 3;
+		}
+
+		/* Link it into the list */
+		*prev = entry;
+		prev = &entry->next;
+		totalsize += size;
+	}
+	free(path);
+	free(dirlist);		/* allocated by scandir() with malloc() */
+	return totalsize;
+}
+
+/* Returns sizeof(struct cramfs_super), which includes the root inode. */
+static unsigned int write_superblock(struct entry *root, char *base, int size)
+{
+	struct cramfs_super *super = (struct cramfs_super *) base;
+	unsigned int offset = sizeof(struct cramfs_super) + image_length;
+
+	if (opt_pad) {
+		offset += opt_pad;
+	}
+
+	super->magic = CRAMFS_MAGIC;
+	super->flags = CRAMFS_FLAG_FSID_VERSION_2 | CRAMFS_FLAG_SORTED_DIRS;
+	if (opt_holes)
+		super->flags |= CRAMFS_FLAG_HOLES;
+	if (image_length > 0)
+		super->flags |= CRAMFS_FLAG_SHIFTED_ROOT_OFFSET;
+	super->size = size;
+	memcpy(super->signature, CRAMFS_SIGNATURE, sizeof(super->signature));
+
+	super->fsid.crc = crc32(0L, NULL, 0);
+	super->fsid.edition = opt_edition;
+	super->fsid.blocks = total_blocks;
+	super->fsid.files = total_nodes;
+
+	memset(super->name, 0x00, sizeof(super->name));
+	if (opt_name)
+		str2memcpy((char *)super->name, opt_name, sizeof(super->name));
+	else
+		str2memcpy((char *)super->name, "Compressed", sizeof(super->name));
+
+	super->root.mode = root->mode;
+	super->root.uid = root->uid;
+	super->root.gid = root->gid;
+	super->root.size = root->size;
+	super->root.offset = offset >> 2;
+
+	super_toggle_endianness(cramfs_is_big_endian, super);
+	inode_from_host(cramfs_is_big_endian, &super->root, &super->root);
+
+	return offset;
+}
+
+static void set_data_offset(struct entry *entry, char *base, unsigned long offset)
+{
+	struct cramfs_inode *inode = (struct cramfs_inode *) (base + entry->dir_offset);
+	inode_to_host(cramfs_is_big_endian, inode, inode);
+	if (offset >= (1 << (2 + CRAMFS_OFFSET_WIDTH)))
+		errx(MKFS_EX_ERROR, _("filesystem too big.  Exiting."));
+	inode->offset = (offset >> 2);
+	inode_from_host(cramfs_is_big_endian, inode, inode);
+}
+
+
+/*
+ * We do a width-first printout of the directory
+ * entries, using a stack to remember the directories
+ * we've seen.
+ */
+static unsigned int write_directory_structure(struct entry *entry, char *base, unsigned int offset)
+{
+	int stack_entries = 0;
+	int stack_size = 64;
+	struct entry **entry_stack;
+
+	entry_stack = xmalloc(stack_size * sizeof(struct entry *));
+
+	for (;;) {
+		int dir_start = stack_entries;
+		while (entry) {
+			struct cramfs_inode *inode =
+				(struct cramfs_inode *) (base + offset);
+			size_t len = strlen((const char *)entry->name);
+
+			entry->dir_offset = offset;
+
+			inode->mode = entry->mode;
+			inode->uid = entry->uid;
+			inode->gid = entry->gid;
+			inode->size = entry->size;
+			inode->offset = 0;
+			/* Non-empty directories, regfiles and symlinks will
+			   write over inode->offset later. */
+
+			offset += sizeof(struct cramfs_inode);
+			total_nodes++;	/* another node */
+			memcpy(base + offset, entry->name, len);
+			/* Pad up the name to a 4-byte boundary */
+			while (len & 3) {
+				*(base + offset + len) = '\0';
+				len++;
+			}
+			inode->namelen = len >> 2;
+			offset += len;
+
+			if (verbose)
+				printf("  %s\n", entry->name);
+			if (entry->child) {
+				if (stack_entries >= stack_size) {
+					stack_size *= 2;
+					entry_stack = xrealloc(entry_stack, stack_size * sizeof(struct entry *));
+				}
+				entry_stack[stack_entries] = entry;
+				stack_entries++;
+			}
+			inode_from_host(cramfs_is_big_endian, inode, inode);
+			entry = entry->next;
+		}
+
+		/*
+		 * Reverse the order the stack entries pushed during
+		 * this directory, for a small optimization of disk
+		 * access in the created fs.  This change makes things
+		 * `ls -UR' order.
+		 */
+		{
+			struct entry **lo = entry_stack + dir_start;
+			struct entry **hi = entry_stack + stack_entries;
+			struct entry *tmp;
+
+			while (lo < --hi) {
+				tmp = *lo;
+				*lo++ = *hi;
+				*hi = tmp;
+			}
+		}
+
+		/* Pop a subdirectory entry from the stack, and recurse. */
+		if (!stack_entries)
+			break;
+		stack_entries--;
+		entry = entry_stack[stack_entries];
+
+		set_data_offset(entry, base, offset);
+		if (verbose)
+			printf("'%s':\n", entry->name);
+		entry = entry->child;
+	}
+	free(entry_stack);
+	return offset;
+}
+
+static int is_zero(unsigned char const *begin, unsigned len)
+{
+	if (opt_holes)
+		/* Returns non-zero iff the first LEN bytes from BEGIN are
+		   all NULs. */
+		return (len-- == 0 ||
+			(begin[0] == '\0' &&
+			 (len-- == 0 ||
+			  (begin[1] == '\0' &&
+			   (len-- == 0 ||
+			    (begin[2] == '\0' &&
+			     (len-- == 0 ||
+			      (begin[3] == '\0' &&
+			       memcmp(begin, begin + 4, len) == 0))))))));
+
+	/* Never create holes. */
+	return 0;
+}
+
+/*
+ * One 4-byte pointer per block and then the actual blocked
+ * output. The first block does not need an offset pointer,
+ * as it will start immediately after the pointer block;
+ * so the i'th pointer points to the end of the i'th block
+ * (i.e. the start of the (i+1)'th block or past EOF).
+ *
+ * Note that size > 0, as a zero-sized file wouldn't ever
+ * have gotten here in the first place.
+ */
+static unsigned int
+do_compress(char *base, unsigned int offset, unsigned char const *name,
+	    char *path, unsigned int size, unsigned int mode)
+{
+	unsigned long original_size, original_offset, new_size, blocks, curr;
+	long change;
+	char *start;
+	Bytef *p;
+
+	/* get uncompressed data */
+	start = do_mmap(path, size, mode);
+	if (start == NULL)
+		return offset;
+	p = (Bytef *) start;
+
+	original_size = size;
+	original_offset = offset;
+	blocks = (size - 1) / blksize + 1;
+	curr = offset + 4 * blocks;
+
+	total_blocks += blocks;
+
+	do {
+		uLongf len = 2 * blksize;
+		uLongf input = size;
+		if (input > blksize)
+			input = blksize;
+		size -= input;
+		if (!is_zero (p, input)) {
+			compress((Bytef *)(base + curr), &len, p, input);
+			curr += len;
+		}
+		p += input;
+
+		if (len > blksize*2) {
+			/* (I don't think this can happen with zlib.) */
+			printf(_("AIEEE: block \"compressed\" to > "
+				 "2*blocklength (%ld)\n"),
+			       len);
+			exit(MKFS_EX_ERROR);
+		}
+
+		*(uint32_t *) (base + offset) = u32_toggle_endianness(cramfs_is_big_endian, curr);
+		offset += 4;
+	} while (size);
+
+	do_munmap(start, original_size, mode);
+
+	curr = (curr + 3) & ~3;
+	new_size = curr - original_offset;
+	/* TODO: Arguably, original_size in these 2 lines should be
+	   st_blocks * 512.  But if you say that, then perhaps
+	   administrative data should also be included in both. */
+	change = new_size - original_size;
+	if (verbose)
+		printf(_("%6.2f%% (%+ld bytes)\t%s\n"),
+		       (change * 100) / (double) original_size, change, name);
+
+	return curr;
+}
+
+
+/*
+ * Traverse the entry tree, writing data for every item that has
+ * non-null entry->path (i.e. every symlink and non-empty
+ * regfile).
+ */
+static unsigned int
+write_data(struct entry *entry, char *base, unsigned int offset) {
+	struct entry *e;
+
+	for (e = entry; e; e = e->next) {
+		if (e->path) {
+			if (e->same) {
+				set_data_offset(e, base, e->same->offset);
+				e->offset = e->same->offset;
+			} else if (e->size) {
+				set_data_offset(e, base, offset);
+				e->offset = offset;
+				offset = do_compress(base, offset, e->name,
+						     e->path, e->size,e->mode);
+			}
+		} else if (e->child)
+			offset = write_data(e->child, base, offset);
+	}
+	return offset;
+}
+
+static unsigned int write_file(char *file, char *base, unsigned int offset)
+{
+	int fd;
+	char *buf;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0)
+		err(MKFS_EX_ERROR, _("cannot open %s"), file);
+	buf = mmap(NULL, image_length, PROT_READ, MAP_PRIVATE, fd, 0);
+	memcpy(base + offset, buf, image_length);
+	munmap(buf, image_length);
+	if (close (fd) < 0)
+		err(MKFS_EX_ERROR, _("cannot close file %s"), file);
+	/* Pad up the image_length to a 4-byte boundary */
+	while (image_length & 3) {
+		*(base + offset + image_length) = '\0';
+		image_length++;
+	}
+	return (offset + image_length);
+}
+
+/*
+ * Maximum size fs you can create is roughly 256MB.  (The last file's
+ * data must begin within 256MB boundary but can extend beyond that.)
+ *
+ * Note that if you want it to fit in a ROM then you're limited to what the
+ * hardware and kernel can support (64MB?).
+ */
+static unsigned int
+maxfslen(void) {
+	return (((1 << CRAMFS_OFFSET_WIDTH) - 1) << 2)    /* offset */
+		+ (1 << CRAMFS_SIZE_WIDTH) - 1            /* filesize */
+		+ (1 << CRAMFS_SIZE_WIDTH) * 4 / blksize; /* block pointers */
+}
+
+/*
+ * Usage:
+ *
+ *      mkcramfs directory-name outfile
+ *
+ * where "directory-name" is simply the root of the directory
+ * tree that we want to generate a compressed filesystem out
+ * of.
+ */
+int main(int argc, char **argv)
+{
+	struct stat st;		/* used twice... */
+	struct entry *root_entry;
+	char *rom_image;
+	ssize_t offset, written;
+	int fd;
+	/* initial guess (upper-bound) of required filesystem size */
+	loff_t fslen_ub = sizeof(struct cramfs_super);
+	unsigned int fslen_max;
+	char const *dirname, *outfile;
+	char *lockmode = 0;
+	uint32_t crc = crc32(0L, NULL, 0);
+	int c;
+	cramfs_is_big_endian = HOST_IS_BIG_ENDIAN; /* default is to use host order */
+
+	total_blocks = 0;
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+	close_stdout_atexit();
+
+	if (argc > 1) {
+		/* first arg may be one of our standard longopts */
+		if (!strcmp(argv[1], "--help"))
+			usage();
+		if (!strcmp(argv[1], "--version")) {
+			print_version(EXIT_SUCCESS);
+			exit(MKFS_EX_OK);
+		}
+	}
+	strutils_set_exitcode(MKFS_EX_USAGE);
+
+	/* command line options */
+	while ((c = getopt(argc, argv, "hb:Ee:i:n:N:l::psVvz")) != EOF) {
+		switch (c) {
+		case 'h':
+			usage();
+		case 'b':
+			blksize = strtou32_or_err(optarg, _("invalid blocksize argument"));
+			break;
+		case 'E':
+			opt_errors = 1;
+			break;
+		case 'e':
+			opt_edition = strtou32_or_err(optarg, _("invalid edition number argument"));
+			break;
+		case 'N':
+			if (strcmp(optarg, "big") == 0)
+				cramfs_is_big_endian = 1;
+			else if (strcmp(optarg, "little") == 0)
+				cramfs_is_big_endian = 0;
+			else if (strcmp(optarg, "host") == 0)
+				/* default */ ;
+			else
+				errx(MKFS_EX_USAGE, _("invalid endianness given;"
+						   " must be 'big', 'little', or 'host'"));
+			break;
+		case 'i':
+			opt_image = optarg;
+			if (lstat(opt_image, &st) < 0)
+				err(MKFS_EX_USAGE, _("stat of %s failed"), opt_image);
+			image_length = st.st_size; /* may be padded later */
+			fslen_ub += (image_length + 3); /* 3 is for padding */
+			break;
+		case 'l':
+                        lockmode = "1";
+			if (optarg) {
+                                if (*optarg == '=')
+					optarg++;
+				lockmode = optarg;
+			}
+			break;
+		case 'n':
+			opt_name = optarg;
+			break;
+		case 'p':
+			opt_pad = PAD_SIZE;
+			fslen_ub += PAD_SIZE;
+			break;
+		case 's':
+			/* old option, ignored */
+			break;
+		case 'V':
+			print_version(MKFS_EX_OK);
+		case 'v':
+			verbose = 1;
+			break;
+		case 'z':
+			opt_holes = 1;
+			break;
+		default:
+			errtryhelp(MKFS_EX_USAGE);
+		}
+	}
+
+	if ((argc - optind) != 2) {
+		warnx(_("bad usage"));
+		errtryhelp(MKFS_EX_USAGE);
+	}
+	dirname = argv[optind];
+	outfile = argv[optind + 1];
+
+	if (blksize == 0)
+		blksize = getpagesize();
+
+	if (stat(dirname, &st) < 0)
+		err(MKFS_EX_USAGE, _("stat of %s failed"), dirname);
+	fd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0)
+		err(MKFS_EX_USAGE, _("cannot open %s"), outfile);
+
+        if (blkdev_lock(fd, outfile, lockmode) != 0)
+		exit(MKFS_EX_ERROR);
+
+	root_entry = xcalloc(1, sizeof(struct entry));
+	root_entry->mode = st.st_mode;
+	root_entry->uid = st.st_uid;
+	root_entry->gid = st.st_gid;
+
+	root_entry->size = parse_directory(root_entry, dirname, &root_entry->child, &fslen_ub);
+
+	/* find duplicate files */
+	eliminate_doubles(root_entry,root_entry, &fslen_ub);
+
+	/* always allocate a multiple of blksize bytes because that's
+	   what we're going to write later on */
+	fslen_ub = ((fslen_ub - 1) | (blksize - 1)) + 1;
+	fslen_max = maxfslen();
+
+	if (fslen_ub > fslen_max) {
+		warnx(	_("warning: guestimate of required size (upper bound) "
+			  "is %lldMB, but maximum image size is %uMB.  "
+			  "We might die prematurely."),
+			(long long)fslen_ub >> 20,
+			fslen_max >> 20);
+		fslen_ub = fslen_max;
+	}
+
+	/* TODO: Why do we use a private/anonymous mapping here
+	   followed by a write below, instead of just a shared mapping
+	   and a couple of ftruncate calls?  Is it just to save us
+	   having to deal with removing the file afterwards?  If we
+	   really need this huge anonymous mapping, we ought to mmap
+	   in smaller chunks, so that the user doesn't need nn MB of
+	   RAM free.  If the reason is to be able to write to
+	   un-mmappable block devices, then we could try shared mmap
+	   and revert to anonymous mmap if the shared mmap fails. */
+	rom_image = mmap(NULL,
+			 fslen_ub?fslen_ub:1,
+			 PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS,
+			 -1, 0);
+
+	if (-1 == (int) (long) rom_image)
+		err(MKFS_EX_ERROR, _("ROM image map"));
+
+	/* Skip the first opt_pad bytes for boot loader code */
+	offset = opt_pad;
+	memset(rom_image, 0x00, opt_pad);
+
+	/* Skip the superblock and come back to write it later. */
+	offset += sizeof(struct cramfs_super);
+
+	/* Insert a file image. */
+	if (opt_image) {
+		if (verbose)
+			printf(_("Including: %s\n"), opt_image);
+		offset = write_file(opt_image, rom_image, offset);
+	}
+
+	offset = write_directory_structure(root_entry->child, rom_image, offset);
+	if (verbose)
+		printf(_("Directory data: %zd bytes\n"), offset);
+
+	offset = write_data(root_entry, rom_image, offset);
+
+	/* We always write a multiple of blksize bytes, so that
+	   losetup works. */
+	offset = ((offset - 1) | (blksize - 1)) + 1;
+	if (verbose)
+		printf(_("Everything: %zd kilobytes\n"), offset >> 10);
+
+	/* Write the superblock now that we can fill in all of the fields. */
+	write_superblock(root_entry, rom_image+opt_pad, offset);
+	if (verbose)
+		printf(_("Super block: %zd bytes\n"),
+		       sizeof(struct cramfs_super));
+
+	/* Put the checksum in. */
+	crc = crc32(crc, (unsigned char *) (rom_image+opt_pad), (offset-opt_pad));
+	((struct cramfs_super *) (rom_image+opt_pad))->fsid.crc = u32_toggle_endianness(cramfs_is_big_endian, crc);
+	if (verbose)
+		printf(_("CRC: %x\n"), crc);
+
+	/* Check to make sure we allocated enough space. */
+	if (fslen_ub < offset)
+		errx(MKFS_EX_ERROR,
+			_("not enough space allocated for ROM image "
+			  "(%lld allocated, %zu used)"),
+			(long long) fslen_ub, offset);
+
+	written = write(fd, rom_image, offset);
+	if (offset != written)
+		errx(MKFS_EX_ERROR, _("ROM image write failed (%zd %zd)"),
+			written, offset);
+	if (close_fd(fd) != 0)
+		err(MKFS_EX_ERROR, _("ROM image"));
+
+	/*
+	 * (These warnings used to come at the start, but they scroll off
+	 * the screen too quickly.)
+	 */
+	if (warn_namelen)
+		/* Can't happen when reading from ext2fs. */
+		/* Bytes, not chars: think UTF8. */
+		warnx(_("warning: filenames truncated to %u bytes."), MAX_INPUT_NAMELEN);
+	if (warn_skip)
+		warnx(_("warning: files were skipped due to errors."));
+	if (warn_size)
+		warnx(_("warning: file sizes truncated to %luMB "
+			"(minus 1 byte)."), 1L << (CRAMFS_SIZE_WIDTH - 20));
+	if (warn_uid)
+		/* (not possible with current Linux versions) */
+		warnx(_("warning: uids truncated to %u bits.  "
+			"(This may be a security concern.)"), CRAMFS_UID_WIDTH);
+	if (warn_gid)
+		warnx(_("warning: gids truncated to %u bits.  "
+			"(This may be a security concern.)"), CRAMFS_GID_WIDTH);
+	if (warn_dev)
+		warnx(_("WARNING: device numbers truncated to %u bits.  "
+			"This almost certainly means\n"
+			"that some device files will be wrong."),
+		      CRAMFS_OFFSET_WIDTH);
+	if (opt_errors &&
+	    (warn_namelen|warn_skip|warn_size|warn_uid|warn_gid|warn_dev))
+		exit(MKFS_EX_ERROR);
+
+	return MKFS_EX_OK;
+}