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Diffstat (limited to '')
| -rw-r--r-- | disk-utils/mkfs.cramfs.c | 926 |
1 files changed, 926 insertions, 0 deletions
diff --git a/disk-utils/mkfs.cramfs.c b/disk-utils/mkfs.cramfs.c new file mode 100644 index 0000000..bf07f8c --- /dev/null +++ b/disk-utils/mkfs.cramfs.c @@ -0,0 +1,926 @@ +/* + * 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 "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) +{ + printf( + _("usage: %s [-h] [-v] [-b blksize] [-e edition] [-N endian] [-i file] " + "[-n name] dirname outfile\n" + " -v be verbose\n" + " -E make all warnings errors " + "(non-zero exit status)\n" + " -b blksize use this blocksize, must equal page size\n" + " -e edition set edition number (part of fsid)\n" + " -N endian set cramfs endianness (big|little|host), default host\n" + " -i file insert a file image into the filesystem\n" + " -n name set name of cramfs filesystem\n" + " -p pad by %d bytes for boot code\n" + " -s sort directory entries (old option, ignored)\n" + " -z make explicit holes\n" + " dirname root of the filesystem to be compressed\n" + " outfile output file\n"), + program_invocation_short_name, PAD_SIZE); + + 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)) { + 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)))))))); + else + /* 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; + 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); + atexit(close_stdout); + + if (argc > 1) { + /* first arg may be one of our standard longopts */ + if (!strcmp(argv[1], "--help")) + usage(); + if (!strcmp(argv[1], "--version")) { + printf(UTIL_LINUX_VERSION); + exit(MKFS_EX_OK); + } + } + strutils_set_exitcode(MKFS_EX_USAGE); + + /* command line options */ + while ((c = getopt(argc, argv, "hb:Ee:i:n:N: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 'n': + opt_name = optarg; + break; + case 'p': + opt_pad = PAD_SIZE; + fslen_ub += PAD_SIZE; + break; + case 's': + /* old option, ignored */ + break; + case 'V': + printf(UTIL_LINUX_VERSION); + exit(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); + + 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; +} |