Modify inode attributes in the ext2 File System

#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <ctype.h>#include <string.h>#include <time.h>#include <getopt.h>#include <errno.h>#include <fcntl.h>#include <sys/types.h>#include <sys/stat.h>#include <ext2fs/ext2fs.h>/* * Flags used by the common argument processing functions */#define CHECK_FS_RW0x0001#define CHECK_FS_BITMAPS0x0002#define CHECK_FS_NOTOPEN0x0004#ifdef DLL_EXPORT#define DLLEXPORT __declspec(dllexport)#else#define DLLEXPORT#endifext2_filsyscurrent_fs = NULL;ext2_ino_troot, cwd;DLLEXPORTint open_filesystem(char *device, int open_flags, blk_t superblock,    blk_t blocksize, int catastrophic){intretval;if (superblock != 0 && blocksize == 0) {com_err(device, 0, "if you specify the superblock, you must also specify the block size");current_fs = NULL;return;}if (catastrophic && (open_flags & EXT2_FLAG_RW)) {com_err(device, 0,"opening read-only because of catastrophic mode");open_flags &= ~EXT2_FLAG_RW;}retval = ext2fs_open(device, open_flags, superblock, blocksize,     nt_io_manager(), ¤t_fs);if (retval) {com_err(device, retval, "while opening filesystem");current_fs = NULL;return;}if (catastrophic)com_err(device, 0, "catastrophic mode - not reading inode or group bitmaps");else {retval = ext2fs_read_inode_bitmap(current_fs);if (retval) {com_err(device, retval, "while reading inode bitmap");goto errout;}retval = ext2fs_read_block_bitmap(current_fs);if (retval) {com_err(device, retval, "while reading block bitmap");goto errout;}}root = cwd = EXT2_ROOT_INO;return 0;errout:retval = ext2fs_close(current_fs);if (retval)com_err(device, retval, "while trying to close filesystem");current_fs = NULL;return -1;}DLLEXPORTvoid close_filesystem(void){intretval;if (current_fs->flags & EXT2_FLAG_IB_DIRTY) {retval = ext2fs_write_inode_bitmap(current_fs);if (retval)com_err("ext2fs_write_inode_bitmap", retval, "");}if (current_fs->flags & EXT2_FLAG_BB_DIRTY) {retval = ext2fs_write_block_bitmap(current_fs);if (retval)com_err("ext2fs_write_block_bitmap", retval, "");}retval = ext2fs_close(current_fs);if (retval)com_err("ext2fs_close", retval, "");current_fs = NULL;return;}/* * This routine is used whenever a command needs to turn a string into * an inode. */ext2_ino_t string_to_inode(char *str){ext2_ino_tino;intlen = strlen(str);char*end;intretval;/* * If the string is of the form <ino>, then treat it as an * inode number. */if ((len > 2) && (str[0] == '<') && (str[len-1] == '>')) {ino = strtoul(str+1, &end, 0);if (*end=='>')return ino;}retval = ext2fs_namei(current_fs, root, cwd, str, &ino);if (retval) {com_err(str, retval, "");return 0;}return ino;}/* * This routine returns 1 if the filesystem is not open, and prints an * error message to that effect. */int check_fs_open(char *name){if (!current_fs) {com_err(name, 0, "Filesystem not open");return 1;}return 0;}/* * This routine returns 1 if a filesystem is open, and prints an * error message to that effect. */int check_fs_not_open(char *name){if (current_fs) {com_err(name, 0,"Filesystem %s is still open.  Close it first.\n",current_fs->device_name);return 1;}return 0;}/* * This routine returns 1 if a filesystem is not opened read/write, * and prints an error message to that effect. */int check_fs_read_write(char *name){if (!(current_fs->flags & EXT2_FLAG_RW)) {com_err(name, 0, "Filesystem opened read/only");return 1;}return 0;}/* * This routine returns 1 if a filesystem is doesn't have its inode * and block bitmaps loaded, and prints an error message to that * effect. */int check_fs_bitmaps(char *name){if (!current_fs->block_map || !current_fs->inode_map) {com_err(name, 0, "Filesystem bitmaps not loaded");return 1;}return 0;}/* * This function takes a __u32 time value and converts it to a string, * using ctime */char *time_to_string(__u32 cl){time_tt = (time_t) cl;return ctime(&t);}int debugfs_read_inode(ext2_ino_t ino, struct ext2_inode * inode,const char *cmd){int retval;retval = ext2fs_read_inode(current_fs, ino, inode);if (retval) {com_err(cmd, retval, "while reading inode %u", ino);return 1;}return 0;}int debugfs_write_inode(ext2_ino_t ino, struct ext2_inode * inode,const char *cmd){int retval;retval = ext2fs_write_inode(current_fs, ino, inode);if (retval) {com_err(cmd, retval, "while writing inode %u", ino);return 1;}return 0;}/* * This is a common helper function used by the command processing * routines */int common_args_process(int argc, char *argv[], int min_argc, int max_argc,const char *cmd, const char *usage, int flags){if (argc < min_argc || argc > max_argc) {com_err(argv[0], 0, "Usage: %s %s", cmd, usage);return 1;}if (flags & CHECK_FS_NOTOPEN) {if (check_fs_not_open(argv[0]))return 1;} else {if (check_fs_open(argv[0]))return 1;}if ((flags & CHECK_FS_RW) && check_fs_read_write(argv[0]))return 1;if ((flags & CHECK_FS_BITMAPS) && check_fs_bitmaps(argv[0]))return 1;return 0;}/* * This is a helper function used by do_stat, do_freei, do_seti, and * do_testi, etc.  Basically, any command which takes a single * argument which is a file/inode number specifier. */int common_inode_args_process(int argc, char *argv[],      ext2_ino_t *inode, int flags){if (common_args_process(argc, argv, 2, 2, argv[0], "<file>", flags))return 1;*inode = string_to_inode(argv[1]);if (!*inode) return 1;return 0;}static void modify_u16(char *com, const char *prompt,       const char *format, __u16 *val){char buf[200];unsigned long v;char *tmp;sprintf(buf, format, *val);printf("%30s    [%s] ", prompt, buf);fgets(buf, sizeof(buf), stdin);if (buf[strlen (buf) - 1] == '\n')buf[strlen (buf) - 1] = '\0';if (!buf[0])return;v = strtoul(buf, &tmp, 0);if (*tmp)com_err(com, 0, "Bad value - %s", buf);else*val = v;}static void modify_u32(char *com, const char *prompt,       const char *format, __u32 *val){char buf[200];unsigned long v;char *tmp;sprintf(buf, format, *val);printf("%30s    [%s] ", prompt, buf);fgets(buf, sizeof(buf), stdin);if (buf[strlen (buf) - 1] == '\n')buf[strlen (buf) - 1] = '\0';if (!buf[0])return;v = strtoul(buf, &tmp, 0);if (*tmp)com_err(com, 0, "Bad value - %s", buf);else*val = v;}#define COMMAND_MI "mi"DLLEXPORTvoid do_modify_inode(int readonly, char *filename, unsigned long mode){struct ext2_inode inode;ext2_ino_tinode_num;int i;unsigned char*frag, *fsize;charbuf[80];int os;const char*hex_format = "0x%x";const char*octal_format = "0%o";const char*decimal_format = "%d";inode_num = string_to_inode(filename);if (!inode_num) return ;/*if (common_inode_args_process(argc, argv, &inode_num, CHECK_FS_RW))return;*/os = current_fs->super->s_creator_os;if (debugfs_read_inode(inode_num, &inode, filename))return;printf("Current Mode   [0%o] \n", inode.i_mode);inode.i_mode = mode;#if 0modify_u16(COMMAND_MI, "Mode", octal_format, &inode.i_mode);modify_u16(COMMAND_MI, "User ID", decimal_format, &inode.i_uid);modify_u16(COMMAND_MI, "Group ID", decimal_format, &inode.i_gid);modify_u32(COMMAND_MI, "Size", decimal_format, &inode.i_size);modify_u32(COMMAND_MI, "Creation time", decimal_format, &inode.i_ctime);modify_u32(COMMAND_MI, "Modification time", decimal_format, &inode.i_mtime);modify_u32(COMMAND_MI, "Access time", decimal_format, &inode.i_atime);modify_u32(COMMAND_MI, "Deletion time", decimal_format, &inode.i_dtime);modify_u16(COMMAND_MI, "Link count", decimal_format, &inode.i_links_count);modify_u32(COMMAND_MI, "Block count", decimal_format, &inode.i_blocks);modify_u32(COMMAND_MI, "File flags", hex_format, &inode.i_flags);modify_u32(COMMAND_MI, "Generation", hex_format, &inode.i_generation);#if 0          modify_u32(COMMAND_MI, "Reserved1", decimal_format, &inode.i_reserved1);#endifmodify_u32(COMMAND_MI, "File acl", decimal_format, &inode.i_file_acl);if (LINUX_S_ISDIR(inode.i_mode))modify_u32(argv[0], "Directory acl", decimal_format, &inode.i_dir_acl);elsemodify_u32(argv[0], "High 32bits of size", decimal_format, &inode.i_size_high);if (current_fs->super->s_creator_os == EXT2_OS_HURD)modify_u32(argv[0], "Translator Block",    decimal_format, &inode.osd1.hurd1.h_i_translator);modify_u32(argv[0], "Fragment address", decimal_format, &inode.i_faddr);switch (os) {    case EXT2_OS_LINUX:frag = &inode.osd2.linux2.l_i_frag;fsize = &inode.osd2.linux2.l_i_fsize;break;    case EXT2_OS_HURD:frag = &inode.osd2.hurd2.h_i_frag;fsize = &inode.osd2.hurd2.h_i_fsize;break;    case EXT2_OS_MASIX:frag = &inode.osd2.masix2.m_i_frag;fsize = &inode.osd2.masix2.m_i_fsize;break;    default:frag = fsize = 0;}if (frag)modify_u8(argv[0], "Fragment number", decimal_format, frag);if (fsize)modify_u8(argv[0], "Fragment size", decimal_format, fsize);for (i=0;  i < EXT2_NDIR_BLOCKS; i++) {sprintf(buf, "Direct Block #%d", i);modify_u32(argv[0], buf, decimal_format, &inode.i_block[i]);}modify_u32(argv[0], "Indirect Block", decimal_format,    &inode.i_block[EXT2_IND_BLOCK]);    modify_u32(argv[0], "Double Indirect Block", decimal_format,    &inode.i_block[EXT2_DIND_BLOCK]);modify_u32(argv[0], "Triple Indirect Block", decimal_format,    &inode.i_block[EXT2_TIND_BLOCK]);#endifif (readonly)return;if (debugfs_write_inode(inode_num, &inode, filename))return;}/* * This function will convert a string to an unsigned long, printing * an error message if it fails, and returning success or failure in err. */unsigned long parse_ulong(const char *str, const char *cmd,  const char *descr, int *err){char*tmp;unsigned longret;ret = strtoul(str, &tmp, 0);if (*tmp == 0) {if (err)*err = 0;return ret;}com_err(cmd, 0, "Bad %s - %s", descr, str);if (err)*err = 1;elseexit(1);return 0;}/* * This function will convert a string to a block number.  It returns * 0 on success, 1 on failure. */int strtoblk(const char *cmd, const char *str, blk_t *ret){blk_tblk;interr;blk = parse_ulong(str, cmd, "block number", &err);*ret = blk;if (err == 0 && blk == 0) {com_err(cmd, 0, "Invalid block number 0");err = 1;}return err;}#ifdef MOD_EXEint main(int argc, char **argv){intcatastrophic = 0;blk_tsuperblock = 0;blk_tblocksize = 0;int open_flags = 0;char *file_path = NULL;char *dev_path = NULL;int c = 0;const char*usage = "Usage: chmod [-b blocksize] [-s superblock] [-f file] [-F] [-V] [-c] [-i] [-r] [-o device]";unsigned long mode;char *tmp = NULL;int readonly = 0;open_flags |= EXT2_FLAG_RW;while ((c = getopt (argc, argv, "icRF:f:b:s:o:Vr")) != EOF) {switch (c) {case 'F':open_flags |= EXT2_FLAG_FORCE;break;case 'f':file_path = optarg;break;case 'i':open_flags |= EXT2_FLAG_IMAGE_FILE;break;case 'o':dev_path = optarg;break;case 'b':blocksize = parse_ulong(optarg, argv[0], "block size", 0);break;case 's':superblock = parse_ulong(optarg, argv[0],  "superblock number", 0);break;case 'c':catastrophic = 1;break;case 'r':readonly = 1;break;case 'V':/* Print version number and exit */fprintf(stderr, "\tUsing %s\n",error_message(EXT2_ET_BASE));exit(0);default:com_err(argv[0], 0, usage);return 1;}}if (!file_path || !dev_path || (!readonly && !argv[optind])){com_err(argv[0], 0, usage);return 1;}if (!readonly) {printf("Change Mode   [%s] \n", argv[optind]);mode = strtoul(argv[optind], &tmp, 0);if (*tmp){com_err(argv[0], 0, "Bad Mode value - %s", argv[optind]);return 1;}}open_filesystem(dev_path, open_flags,superblock, blocksize, catastrophic);if (!current_fs){return 1;}do_modify_inode(readonly, file_path, mode);close_filesystem();return 0;}#endif

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