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src/extract.c
2 193 строки
60 KB
Paul Eggert
tar: reuse FD when extracting hard links
30 июл 2026, 09:12
30 июл 2026, 09:12
9371d36
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/* Extract files from a tar archive. Copyright 1988-2026 Free Software Foundation, Inc. This file is part of GNU tar. GNU tar 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 3 of the License, or (at your option) any later version. GNU tar 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, see <http://www.gnu.org/licenses/>. Written by John Gilmore, on 1985-11-19. */ #include <system.h> #include <quotearg.h> #include <errno.h> #include <flexmember.h> #include <hash.h> #include <issymlinkat.h> #include <priv-set.h> #include <root-uid.h> #include <same-inode.h> #include <utimens.h> #include "common.h" dev_t root_device; static bool we_are_root; /* true if our effective uid == 0 */ static mode_t newdir_umask; /* umask when creating new directories */ static mode_t current_umask; /* current umask (which is set to 0 if -p) */ static mode_t const all_mode_bits = ~ (mode_t) 0; #if ! HAVE_FCHMOD && ! defined fchmod # define fchmod(fd, mode) (errno = ENOSYS, -1) #endif #if ! HAVE_FCHOWN && ! defined fchown # define fchown(fd, uid, gid) (errno = ENOSYS, -1) #endif #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \ || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC \ || defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC \ || (defined _WIN32 && ! defined __CYGWIN__)) # define HAVE_BIRTHTIME 1 #else # define HAVE_BIRTHTIME 0 #endif #if HAVE_BIRTHTIME # define BIRTHTIME_EQ(a, b) (timespec_cmp (a, b) == 0) #else # define BIRTHTIME_EQ(a, b) true #endif /* Return true if an error number ERR means the system call is supported in this case. */ static bool implemented (int err) { return ! (err == ENOSYS || err == ENOTSUP || (EOPNOTSUPP != ENOTSUP && err == EOPNOTSUPP)); } /* Return true if NAME contains ".." as a file name component. */ static bool contains_dot_dot (char const *name) { char const *p = name + FILE_SYSTEM_PREFIX_LEN (name); for (;; p++) { if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2])) return true; for (; ! ISSLASH (*p); p++) if (!*p) return false; } } /* List of directories whose statuses we need to extract after we've finished extracting their subsidiary files. Ordinarily the head of the list has the longest name, and each non-head element is an ancestor (in the directory hierarchy) of the preceding element. However, if --absolute-names (-P) or --directory (-h) is used, things get more complicated: if you consider each contiguous subsequence of elements of the form [D]?[^D]*, where [D] represents an element where METADATA_SET and [^D] represents an element where !METADATA_SET, then the head of the subsequence has the longest name, and each non-head element in the subsequence is an ancestor (in the directory hierarchy) of the preceding element. */ struct delayed_set_stat { /* Next directory in list. */ struct delayed_set_stat *next; /* Metadata for this directory. */ dev_t st_dev; ino_t st_ino; mode_t mode; /* The desired mode is MODE & ~ current_umask. */ uid_t uid; gid_t gid; struct timespec atime; struct timespec mtime; /* Whether the metadata are set. If true, do not set the status of this directory until after any delayed links are created. */ bool metadata_set; /* An estimate of the directory's current mode, along with a mask specifying which bits of this estimate are known to be correct. If CURRENT_MODE_MASK is zero, CURRENT_MODE's value doesn't matter. */ mode_t current_mode; mode_t current_mode_mask; /* This directory is an intermediate directory that was created as an ancestor of some other directory; it was not mentioned in the archive, so do not set its uid, gid, atime, or mtime, and don't alter its mode outside of MODE_RWX. */ bool interdir; /* Whether symbolic links should be followed when accessing the directory. */ int atflag; /* Directory that the name is relative to. */ idx_t change_dir; /* extended attributes*/ char *cntx_name; char *acls_a_ptr; idx_t acls_a_len; char *acls_d_ptr; idx_t acls_d_len; struct xattr_map xattr_map; /* Length and contents of name. */ idx_t file_name_len; char *file_name; }; static struct delayed_set_stat *delayed_set_stat_head; /* Table of delayed stat updates hashed by path; null if none. */ static Hash_table *delayed_set_stat_table; /* A link whose creation we have delayed. */ struct delayed_link { /* The next in a list of delayed links that should be made after this delayed link. */ struct delayed_link *next; /* The device, inode number and birthtime of the placeholder. birthtime.tv_nsec is negative if the birthtime is not available. Don't use mtime as this would allow for false matches if some other process removes the placeholder. Don't use ctime as this would cause race conditions and other screwups, e.g., when restoring hard-linked symlinks. */ dev_t st_dev; ino_t st_ino; #if HAVE_BIRTHTIME struct timespec birthtime; #endif /* True if the link is symbolic. */ bool is_symlink; /* The desired metadata, valid only the link is symbolic. */ mode_t mode; uid_t uid; gid_t gid; struct timespec atime; struct timespec mtime; /* The directory that the sources and target are relative to. */ idx_t change_dir; /* A list of sources for this link. The sources are all to be hard-linked together. */ struct string_list *sources; /* SELinux context */ char *cntx_name; /* ACLs */ char *acls_a_ptr; idx_t acls_a_len; char *acls_d_ptr; idx_t acls_d_len; struct xattr_map xattr_map; /* The desired target of the desired link. */ char target[FLEXIBLE_ARRAY_MEMBER]; }; /* Table of delayed links hashed by device and inode; null if none. */ static Hash_table *delayed_link_table; /* A list of the delayed links in tar file order, and the tail of that list. */ static struct delayed_link *delayed_link_head; static struct delayed_link **delayed_link_tail = &delayed_link_head; struct string_list { struct string_list *next; char string[FLEXIBLE_ARRAY_MEMBER]; }; static size_t dl_hash (void const *entry, size_t table_size) { struct delayed_link const *dl = entry; uintmax_t n = dl->st_dev; int nshift = TYPE_WIDTH (n) - TYPE_WIDTH (dl->st_dev); if (0 < nshift) n <<= nshift; n ^= dl->st_ino; return n % table_size; } static bool dl_compare (void const *a, void const *b) { struct delayed_link const *da = a, *db = b; return PSAME_INODE (da, db); } static size_t ds_hash (void const *entry, size_t table_size) { struct delayed_set_stat const *ds = entry; return hash_string (ds->file_name, table_size); } static bool ds_compare (void const *a, void const *b) { struct delayed_set_stat const *dsa = a, *dsb = b; return streq (dsa->file_name, dsb->file_name); } /* Set up to extract files. */ void extr_init (void) { we_are_root = geteuid () == ROOT_UID; same_permissions_option += we_are_root; same_owner_option += we_are_root; /* Option -p clears the kernel umask, so it does not affect proper restoration of file permissions. New intermediate directories will comply with umask at start of program. */ newdir_umask = umask (0); if (0 < same_permissions_option) current_umask = 0; else { umask (newdir_umask); /* restore the kernel umask */ current_umask = newdir_umask; } } /* Use fchmod if possible, fchmodat otherwise. */ static int fd_i_chmod (int fd, char const *file, mode_t mode, int atflag) { if (0 <= fd) { int result = fchmod (fd, mode); if (result == 0 || implemented (errno)) return result; } struct fdbase f = fdbase (file); return f.fd == BADFD ? -1 : fchmodat (f.fd, f.base, mode, atflag); } /* A version of fd_i_chmod which gracefully handles several common error conditions. Additional argument TYPEFLAG is the type of file in tar notation. */ static int fd_chmod (int fd, char const *file_name, int mode, int atflag, char typeflag) { int chmod_errno = fd_i_chmod (fd, file_name, mode, atflag) < 0 ? errno : 0; /* On Solaris, chmod may fail if we don't have PRIV_ALL, because setuid-root files would otherwise be a backdoor. See http://opensolaris.org/jive/thread.jspa?threadID=95826 (2009-09-03). */ if (chmod_errno == EPERM && (mode & S_ISUID) && priv_set_restore_linkdir () == 0) { chmod_errno = fd_i_chmod (fd, file_name, mode, atflag) < 0 ? errno : 0; priv_set_remove_linkdir (); } /* Linux fchmodat does not support AT_SYMLINK_NOFOLLOW, and returns ENOTSUP even when operating on non-symlinks, try again with the flag disabled if it does not appear to be supported and if the file is not a symlink. This introduces a race, alas. */ if (atflag && typeflag != SYMTYPE && ! implemented (chmod_errno)) chmod_errno = fd_i_chmod (fd, file_name, mode, 0) < 0 ? errno : 0; if (chmod_errno && (typeflag != SYMTYPE || implemented (chmod_errno))) { errno = chmod_errno; return -1; } return 0; } /* Use fchown if possible, fchownat otherwise. */ static int fd_chown (int fd, char const *file, uid_t uid, gid_t gid, int atflag) { if (0 <= fd) { int result = fchown (fd, uid, gid); if (result == 0 || implemented (errno)) return result; } struct fdbase f = fdbase (file); return f.fd == BADFD ? -1 : fchownat (f.fd, f.base, uid, gid, atflag); } /* Use fstat if possible, fstatat otherwise. */ static int fd_stat (int fd, char const *file, struct stat *st, int atflag) { if (0 <= fd) return fstat (fd, st); struct fdbase f = fdbase (file); return f.fd == BADFD ? -1 : fstatat (f.fd, f.base, st, atflag); } /* Set the mode for FILE_NAME to MODE. MODE_MASK specifies the bits of MODE that we care about; thus if MODE_MASK is zero, do nothing. If FD is nonnegative, it is a file descriptor for the file. CURRENT_MODE and CURRENT_MODE_MASK specify information known about the file's current mode, using the style of struct delayed_set_stat. TYPEFLAG specifies the type of the file. ATFLAG specifies the flag to use when statting the file. */ static void set_mode (char const *file_name, mode_t mode, mode_t mode_mask, int fd, mode_t current_mode, mode_t current_mode_mask, char typeflag, int atflag) { if (((current_mode ^ mode) | ~ current_mode_mask) & mode_mask) { if (MODE_ALL & ~ (mode_mask & current_mode_mask)) { struct stat st; if (fd_stat (fd, file_name, &st, atflag) < 0) { stat_error (file_name); return; } current_mode = st.st_mode; } current_mode &= MODE_ALL; mode = (current_mode & ~ mode_mask) | (mode & mode_mask); if (current_mode != mode) { if (fd_chmod (fd, file_name, mode, atflag, typeflag) < 0) chmod_error_details (file_name, mode); } } } /* Check time after successfully setting FILE_NAME's time stamp to T. */ static void check_time (char const *file_name, struct timespec t) { if (t.tv_sec < 0) warnopt (WARN_TIMESTAMP, 0, _("%s: implausibly old time stamp %s"), quotearg_colon (file_name), tartime (t, true)); else if (timespec_cmp (volume_start_time, t) < 0) { struct timespec now; gettime (&now); if (timespec_cmp (now, t) < 0) { char buf[TIMESPEC_STRSIZE_BOUND]; struct timespec diff; diff.tv_sec = t.tv_sec - now.tv_sec; diff.tv_nsec = t.tv_nsec - now.tv_nsec; if (diff.tv_nsec < 0) { diff.tv_nsec += BILLION; diff.tv_sec--; } warnopt (WARN_TIMESTAMP, 0, _("%s: time stamp %s is %s s in the future"), quotearg_colon (file_name), tartime (t, true), code_timespec (diff, buf)); } } } /* Restore stat attributes (owner, group, mode and times) for FILE_NAME, using information given in *ST. If FD is nonnegative, it is a file descriptor for the file. CURRENT_MODE and CURRENT_MODE_MASK specify information known about the file's current mode, using the style of struct delayed_set_stat. TYPEFLAG specifies the type of the file. If INTERDIR, this is an intermediate directory. ATFLAG specifies the flag to use when statting the file. */ static void set_stat (char const *file_name, struct tar_stat_info const *st, int fd, mode_t current_mode, mode_t current_mode_mask, char typeflag, bool interdir, int atflag) { /* Do the utime before the chmod because some versions of utime are broken and trash the modes of the file. */ if (! touch_option && ! interdir) { struct timespec ts[2]; if (incremental_option) ts[0] = st->atime; else ts[0].tv_nsec = UTIME_OMIT; ts[1] = st->mtime; int r; if (0 <= fd) r = futimens (fd, ts); if (fd < 0 || (r < 0 && errno == ENOSYS)) { struct fdbase f = fdbase (file_name); r = f.fd == BADFD ? -1 : utimensat (f.fd, f.base, ts, atflag); } if (r == 0) { if (ts[0].tv_nsec != UTIME_OMIT) check_time (file_name, ts[0]); check_time (file_name, ts[1]); } else if (typeflag != SYMTYPE || implemented (errno)) utime_error (file_name); } if (0 < same_owner_option && ! interdir) { /* Some systems allow non-root users to give files away. Once this done, it is not possible anymore to change file permissions. However, setting file permissions now would be incorrect, since they would apply to the wrong user, and there would be a race condition. So, don't use systems that allow non-root users to give files away. */ uid_t uid = st->stat.st_uid; gid_t gid = st->stat.st_gid; if (fd_chown (fd, file_name, uid, gid, atflag) == 0) { /* Changing the owner can clear st_mode bits in some cases. */ if ((current_mode | ~ current_mode_mask) & S_IXUGO) current_mode_mask &= ~ (current_mode & (S_ISUID | S_ISGID)); } else if (typeflag != SYMTYPE || implemented (errno)) chown_error_details (file_name, uid, gid); } set_mode (file_name, st->stat.st_mode & ~ current_umask, 0 < same_permissions_option && ! interdir ? MODE_ALL : MODE_RWX, fd, current_mode, current_mode_mask, typeflag, atflag); /* these three calls must be done *after* fd_chown() call because fd_chown causes that linux capabilities becomes cleared. */ xattrs_xattrs_set (st, file_name, typeflag, true); xattrs_acls_set (st, file_name, typeflag); xattrs_selinux_set (st, file_name, typeflag); } /* Find the direct ancestor of FILE_NAME in the delayed_set_stat list. */ static struct delayed_set_stat * find_direct_ancestor (char const *file_name) { struct delayed_set_stat *h = delayed_set_stat_head; while (h) { if (! h->metadata_set && strncmp (file_name, h->file_name, h->file_name_len) == 0 && ISSLASH (file_name[h->file_name_len]) && (last_component (file_name + h->file_name_len + 1) == file_name + h->file_name_len + 1)) break; h = h->next; } return h; } /* For each entry H in the leading prefix of entries in HEAD that do not have metadata_set marked, mark H and fill in its dev and ino members. Assume HEAD && ! HEAD->metadata_set. */ static void mark_metadata_set (struct delayed_set_stat *head) { struct delayed_set_stat *h = head; do { struct stat st; h->metadata_set = true; if (deref_stat (h->file_name, &st) < 0) stat_error (h->file_name); else { h->st_dev = st.st_dev; h->st_ino = st.st_ino; } } while ((h = h->next) && ! h->metadata_set); } /* Remember to restore stat attributes (owner, group, mode and times) for the directory FILE_NAME, using information given in *ST, once we stop extracting files into that directory. If ST is null, merely create a placeholder node for an intermediate directory that was created by make_directories. NOTICE: this works only if the archive has usual member order, i.e. directory, then the files in that directory. Incremental archive have somewhat reversed order: first go subdirectories, then all other members. To help cope with this case the variable delay_directory_restore_option is set by prepare_to_extract. If an archive was explicitly created so that its member order is reversed, some directory timestamps can be restored incorrectly, e.g.: tar --no-recursion -cf archive dir dir/file1 foo dir/file2 */ static void delay_set_stat (char const *file_name, struct tar_stat_info const *st, mode_t current_mode, mode_t current_mode_mask, mode_t mode, int atflag) { idx_t file_name_len = strlen (file_name); struct delayed_set_stat *data; if (! (delayed_set_stat_table || (delayed_set_stat_table = hash_initialize (0, NULL, ds_hash, ds_compare, NULL)))) xalloc_die (); struct delayed_set_stat key; key.file_name = (char *) file_name; data = hash_lookup (delayed_set_stat_table, &key); if (data) { if (data->interdir) { struct stat real_st; struct fdbase f = fdbase (data->file_name); if (f.fd == BADFD || fstatat (f.fd, f.base, &real_st, data->atflag) < 0) { stat_error (data->file_name); } else { data->st_dev = real_st.st_dev; data->st_ino = real_st.st_ino; } } } else { data = xmalloc (sizeof (*data)); data->next = delayed_set_stat_head; delayed_set_stat_head = data; data->file_name_len = file_name_len; data->file_name = xstrdup (file_name); if (! hash_insert (delayed_set_stat_table, data)) xalloc_die (); data->metadata_set = false; if (st) { data->st_dev = st->stat.st_dev; data->st_ino = st->stat.st_ino; } xattr_map_init (&data->xattr_map); } data->mode = mode; if (st) { data->uid = st->stat.st_uid; data->gid = st->stat.st_gid; data->atime = st->atime; data->mtime = st->mtime; } data->current_mode = current_mode; data->current_mode_mask = current_mode_mask; data->interdir = ! st; data->atflag = atflag; data->change_dir = chdir_current; data->cntx_name = NULL; if (st) assign_string_or_null (&data->cntx_name, st->cntx_name); if (st && st->acls_a_ptr) { data->acls_a_ptr = xmemdup (st->acls_a_ptr, st->acls_a_len + 1); data->acls_a_len = st->acls_a_len; } else { data->acls_a_ptr = NULL; data->acls_a_len = 0; } if (st && st->acls_d_ptr) { data->acls_d_ptr = xmemdup (st->acls_d_ptr, st->acls_d_len + 1); data->acls_d_len = st->acls_d_len; } else { data->acls_d_ptr = NULL; data->acls_d_len = 0; } if (st) xattr_map_copy (&data->xattr_map, &st->xattr_map); if (must_be_dot_or_slash (file_name)) mark_metadata_set (data); } /* If DIR is an intermediate directory created earlier, update its metadata from the current_stat_info and clear, its intermediate status and return true. Return false otherwise. */ static bool update_interdir_set_stat (char const *dir) { if (delayed_set_stat_table) { struct delayed_set_stat key, *data; key.file_name = (char *) dir; data = hash_lookup (delayed_set_stat_table, &key); if (data && data->interdir) { data->st_dev = current_stat_info.stat.st_dev; data->st_ino = current_stat_info.stat.st_ino; data->mode = current_stat_info.stat.st_mode; data->uid = current_stat_info.stat.st_uid; data->gid = current_stat_info.stat.st_gid; data->atime = current_stat_info.atime; data->mtime = current_stat_info.mtime; data->interdir = false; return true; } } return false; } /* Update the delayed_set_stat info for an intermediate directory created within the file name of DIR. The intermediate directory turned out to be the same as this directory, e.g., due to ".." or symbolic links. *DIR_STAT_INFO is the status of the directory. */ static void repair_delayed_set_stat (char const *dir, struct stat const *dir_stat_info) { struct delayed_set_stat *data; for (data = delayed_set_stat_head; data; data = data->next) { struct stat st; struct fdbase f = fdbase (data->file_name); if (f.fd == BADFD || fstatat (f.fd, f.base, &st, data->atflag) < 0) { stat_error (data->file_name); return; } if (psame_inode (&st, dir_stat_info)) { data->st_dev = current_stat_info.stat.st_dev; data->st_ino = current_stat_info.stat.st_ino; data->mode = current_stat_info.stat.st_mode; data->uid = current_stat_info.stat.st_uid; data->gid = current_stat_info.stat.st_gid; data->atime = current_stat_info.atime; data->mtime = current_stat_info.mtime; data->current_mode = st.st_mode; data->current_mode_mask = all_mode_bits; data->interdir = false; return; } } paxerror (0, _("%s: Unexpected inconsistency when making directory"), quotearg_colon (dir)); } static void free_delayed_set_stat (struct delayed_set_stat *data) { free (data->file_name); xattr_map_free (&data->xattr_map); free (data->cntx_name); free (data->acls_a_ptr); free (data->acls_d_ptr); free (data); } void remove_delayed_set_stat (const char *fname) { struct delayed_set_stat *data, *next, *prev = NULL; for (data = delayed_set_stat_head; data; data = next) { next = data->next; if (chdir_current == data->change_dir && streq (data->file_name, fname)) { hash_remove (delayed_set_stat_table, data); free_delayed_set_stat (data); if (prev) prev->next = next; else delayed_set_stat_head = next; return; } else prev = data; } } static void fixup_delayed_set_stat (char const *src, char const *dst) { struct delayed_set_stat *data; for (data = delayed_set_stat_head; data; data = data->next) { if (chdir_current == data->change_dir && streq (data->file_name, src)) { free (data->file_name); data->file_name = xstrdup (dst); data->file_name_len = strlen (dst); return; } } } /* Ensure that a directory exists by creating it and ancestors as needed. If MAKEDIR == MAKEDIR_FULL the directory is FILE_NAME; otherwise it is FILE_NAME's parent directory. Follow symlinks. Do not overwrite existing files. Allow races with other processes that are also trying to create the requested directory. Possibly temporarily modify FILE_NAME if it contains slashes, but restore it before returning. Return: 1 if this function creates the requested directory, 0 if the requested directory likely exists (and if MAKEDIR == MAKEDIR_PARENT_CHECK, check that it does exist), -1 (issuing a diagnostic) otherwise. */ enum makedir { MAKEDIR_PARENT_CHECK = -1, MAKEDIR_PARENT, MAKEDIR_FULL }; static int make_directories (char *file_name, enum makedir makedir) { char *cursor0 = file_name + FILE_SYSTEM_PREFIX_LEN (file_name); /* This function checks directories by trying to mkdir them left to right. If PARENT_ERRNO is negative, no directories have been checked; if zero, the last mkdir succeeded; otherwise, the last mkdir failed with this errno value, and PARENT_END addresses the byte just after the name of the last directory checked. */ char *parent_end; #ifdef lint parent_end = NULL; #endif int parent_errno = -1; for (char *cursor = cursor0; ; cursor++) { mode_t mode; mode_t desired_mode; char c = *cursor; if (! ISSLASH (c)) { if (c) continue; if (makedir <= MAKEDIR_PARENT) break; } /* Avoid mkdir of empty string (if leading or double slash), or where last part of file name is "." or "..". */ bool dotdot = false; if (cursor == cursor0 || ISSLASH (cursor[-1]) || (cursor[-1] == '.' && (cursor == cursor0 + 1 || ISSLASH (cursor[-2]) || (dotdot = (cursor[-2] == '.' && (cursor == cursor0 + 2 || ISSLASH (cursor[-3]))))))) { if (dotdot) { /* Perhaps we created the parent earlier, perhaps not. Play it safe and assume we did not. */ parent_end = cursor; parent_errno = EEXIST; } if (c) continue; break; } *cursor = '\0'; /* truncate the name there */ desired_mode = MODE_RWX & ~ newdir_umask; mode = desired_mode | (we_are_root ? 0 : MODE_WXUSR); struct fdbase f = fdbase (file_name); if (f.fd != BADFD && mkdirat (f.fd, f.base, mode) == 0) { /* Create a struct delayed_set_stat even if mode == desired_mode, because repair_delayed_set_stat may need to update the struct. */ delay_set_stat (file_name, NULL, mode & ~ current_umask, MODE_RWX, desired_mode, AT_SYMLINK_NOFOLLOW); print_for_mkdir (file_name, desired_mode); parent_errno = 0; } else switch (errno) { case ELOOP: case ENAMETOOLONG: case ENOENT: case ENOTDIR: /* FILE_NAME doesn't exist and can't plausibly have been created nearly-simultaneously by some other process; fail now. */ mkdir_error (file_name); *cursor = c; return -1; default: /* FILE_NAME may be an existing directory so do not fail now. Instead, remember this failure and keep going. */ parent_end = cursor; parent_errno = errno; assume (0 < parent_errno); break; } if (!c) break; *cursor = c; } if (parent_errno == 0) return 1; if (parent_errno < 0 || MAKEDIR_PARENT <= makedir) return 0; /* Although the caller wants us to check that the parent is a directory, we did not create it and it is neither the root nor the current directory; so check now. faccessat of "NAME/" is a bit better than fstatat of "NAME" here, as the latter might fail with EOVERFLOW. PARENT_END must point to a nonempty string so it is safe to access PARENT_END[1]. */ char endch1 = parent_end[1]; parent_end[1] = '\0'; struct fdbase f = fdbase (file_name); int result = f.fd == BADFD ? -1 : faccessat (f.fd, f.base, F_OK, AT_EACCESS); parent_end[1] = endch1; if (result < 0) { errno = parent_errno; char endch0 = parent_end[0]; parent_end[0] = '\0'; mkdir_error (file_name); parent_end[0] = endch0; result = -1; } return result; } /* Ensure that the directory DIR exists by creating it and ancestors as needed. Follow symlinks. Do not overwrite existing files. Allow races with other processes that are also trying to create the requested directory. Possibly temporarily modify DIR if it contains slashes, but restore it before returning. Return true if this function creates the requested directory or if it likely exists, -1 (issuing a diagnostic) otherwise. */ bool create_dir (char *dir) { return 0 <= make_directories (dir, MAKEDIR_FULL); } /* Return true if FILE_NAME (with status *STP, if STP) is not a directory, and has a time stamp newer than (or equal to) that of TAR_STAT. */ static bool file_newer_p (const char *file_name, struct stat const *stp, struct tar_stat_info *tar_stat) { struct stat st; if (!stp) { if (deref_stat (file_name, &st) < 0) { if (errno != ENOENT) { stat_warn (file_name); /* Be safer: if the file exists, assume it is newer. */ return true; } return false; } stp = &st; } return (! S_ISDIR (stp->st_mode) && tar_timespec_cmp (tar_stat->mtime, get_stat_mtime (stp)) <= 0); } enum recover { RECOVER_NO, RECOVER_OK, RECOVER_SKIP }; /* Attempt repairing what went wrong with the extraction. Delete an already existing file or create missing intermediate directories. Return RECOVER_OK if we somewhat increased our chances at a successful extraction, RECOVER_NO if there are no chances, and RECOVER_SKIP if the caller should skip extraction of that member. The value of errno is properly restored on returning RECOVER_NO. If REGULAR, the caller was trying to extract onto a regular file. Set *INTERDIR_MADE if an intermediate directory is made as part of the recovery process. */ static enum recover maybe_recoverable (char *file_name, bool regular, bool *interdir_made) { int e = errno; struct stat st; struct stat const *stp = NULL; if (*interdir_made) return RECOVER_NO; switch (e) { case ELOOP: /* With open ("symlink", O_NOFOLLOW|...), POSIX says errno == ELOOP, but some operating systems do not conform to the standard. */ #ifdef EFTYPE /* NetBSD uses errno == EFTYPE; see <http://gnats.netbsd.org/43154>. */ case EFTYPE: #endif /* FreeBSD 8.1 uses errno == EMLINK. */ case EMLINK: /* Tru64 5.1B uses errno == ENOTSUP. */ case ENOTSUP: if (! regular || old_files_option != OVERWRITE_OLD_FILES || dereference_option) break; if (strchr (file_name, '/')) { if (deref_stat (file_name, &st) < 0) break; stp = &st; } /* The caller tried to open a symbolic link with O_NOFOLLOW. Fall through, treating it as an already-existing file. */ FALLTHROUGH; case EEXIST: /* Remove an old file, if the options allow this. */ switch (old_files_option) { case SKIP_OLD_FILES: warnopt (WARN_EXISTING_FILE, 0, _("%s: skipping existing file"), quotearg_colon (file_name)); return RECOVER_SKIP; case KEEP_OLD_FILES: return RECOVER_NO; case KEEP_NEWER_FILES: if (file_newer_p (file_name, stp, ¤t_stat_info)) break; FALLTHROUGH; case DEFAULT_OLD_FILES: case NO_OVERWRITE_DIR_OLD_FILES: case OVERWRITE_OLD_FILES: if (0 < remove_any_file (file_name, ORDINARY_REMOVE_OPTION)) return RECOVER_OK; break; case UNLINK_FIRST_OLD_FILES: break; } FALLTHROUGH; case ENOENT: /* Attempt creating missing intermediate directories. */ if (0 < make_directories (file_name, MAKEDIR_PARENT_CHECK)) { *interdir_made = true; return RECOVER_OK; } break; default: /* Just say we can't do anything about it... */ break; } errno = e; return RECOVER_NO; } /* Restore stat extended attributes (xattr) for FILE_NAME, using information given in *ST. Restore before extraction because they may affect file layout (e.g. on Lustre distributed parallel filesystem - setting info about how many servers is this file striped over, stripe size, mirror copies, etc. in advance dramatically improves the following performance of reading and writing a file). TYPEFLAG specifies the type of the file. Return a negative number (setting errno) on failure, zero if successful but FILE_NAME was not created (e.g., xattrs not available), and a positive number if FILE_NAME was created. */ static int set_xattr (MAYBE_UNUSED char const *file_name, MAYBE_UNUSED struct tar_stat_info const *st, MAYBE_UNUSED mode_t mode, MAYBE_UNUSED char typeflag) { #ifdef HAVE_XATTRS if (xattrs_option && st->xattr_map.xm_size) { struct fdbase f = fdbase (file_name); int r = f.fd == BADFD ? -1 : mknodat (f.fd, f.base, mode | S_IFREG, 0); if (r < 0) return r; xattrs_xattrs_set (st, file_name, typeflag, false); return 1; } #endif return 0; } /* Fix the statuses of all directories whose statuses need fixing, and which are not ancestors of FILE_NAME. If METADATA_SET, do this for all such directories; otherwise, stop at the first directory that is marked to be fixed up only after delayed links are applied. */ static void apply_nonancestor_delayed_set_stat (char const *file_name, bool metadata_set) { idx_t file_name_len = strlen (file_name); bool check_for_renamed_directories = 0; while (delayed_set_stat_head) { struct delayed_set_stat *data = delayed_set_stat_head; bool skip_this_one = 0; struct stat st; mode_t current_mode = data->current_mode; mode_t current_mode_mask = data->current_mode_mask; check_for_renamed_directories |= data->metadata_set; if (metadata_set < data->metadata_set || (data->file_name_len < file_name_len && file_name[data->file_name_len] && (ISSLASH (file_name[data->file_name_len]) || ISSLASH (file_name[data->file_name_len - 1])) && memeq (file_name, data->file_name, data->file_name_len))) break; chdir_do (data->change_dir, false); if (check_for_renamed_directories) { struct fdbase f = fdbase (data->file_name); if (f.fd == BADFD || fstatat (f.fd, f.base, &st, data->atflag) < 0) { stat_error (data->file_name); skip_this_one = 1; } else { current_mode = st.st_mode; current_mode_mask = all_mode_bits; if (!SAME_INODE (st, *data)) { paxerror (0, _("%s: Directory renamed before its status" " could be extracted"), quotearg_colon (data->file_name)); skip_this_one = 1; } } } if (! skip_this_one) { struct tar_stat_info sb; sb.stat.st_mode = data->mode; sb.stat.st_uid = data->uid; sb.stat.st_gid = data->gid; sb.atime = data->atime; sb.mtime = data->mtime; sb.cntx_name = data->cntx_name; sb.acls_a_ptr = data->acls_a_ptr; sb.acls_a_len = data->acls_a_len; sb.acls_d_ptr = data->acls_d_ptr; sb.acls_d_len = data->acls_d_len; sb.xattr_map = data->xattr_map; set_stat (data->file_name, &sb, -1, current_mode, current_mode_mask, DIRTYPE, data->interdir, data->atflag); } delayed_set_stat_head = data->next; hash_remove (delayed_set_stat_table, data); free_delayed_set_stat (data); } } /* Given struct stat of a directory (or directory member) whose ownership or permissions of will be restored later, return the temporary permissions for that directory, sufficiently restrictive so that in the meantime processes owned by other users do not inadvertently create files under this directory that inherit the wrong owner, group, or permissions from the directory. If not root, though, make the directory writeable and searchable at first, so that files can be created under it. */ static int safe_dir_mode (struct stat const *st) { return ((st->st_mode & (0 < same_owner_option || 0 < same_permissions_option ? S_IRWXU : MODE_RWX)) | (we_are_root ? 0 : MODE_WXUSR)); } /* Return true if the base name BASE returned by fdbase corresponds to a file that trivially exists. This is true if BASE is the empty string (which means the original name is a file system root); or if BASE is "." or "..", possibly followed by slashes. */ static bool trivial_base_name (char const *base) { bool dotted = base[0] == '.'; char const *p = base + dotted + (dotted & (base[dotted] == '.')); return !*p | ISSLASH (*p); } /* Extractor functions for various member types */ static bool extract_dir (char *file_name, char UNNAMED (typeflag)) { int status; mode_t mode; mode_t current_mode = 0; mode_t current_mode_mask = 0; int atflag = 0; bool interdir_made = false; /* Save 'root device' to avoid purging mount points. */ if (one_file_system_option && root_device == 0) { struct chdir_id id = chdir_id (); if (id.err) { errno = id.err; stat_diag ("."); } else root_device = id.st_dev; } if (incremental_option) /* Read the entry and delete files that aren't listed in the archive. */ purge_directory (file_name); mode = safe_dir_mode (¤t_stat_info.stat); for (;;) { struct fdbase f = fdbase (file_name); if (f.fd == BADFD) status = -1; else if (trivial_base_name (f.base)) { /* Save a syscall. */ errno = EEXIST; status = -1; } else status = mkdirat (f.fd, f.base, mode); if (status == 0) { current_mode = mode & ~ current_umask; current_mode_mask = MODE_RWX; atflag = AT_SYMLINK_NOFOLLOW; break; } if (errno == EEXIST) { if (interdir_made || keep_directory_symlink_option || old_files_option == NO_OVERWRITE_DIR_OLD_FILES || old_files_option == DEFAULT_OLD_FILES || old_files_option == OVERWRITE_OLD_FILES) { struct stat st; if (fstatat (f.fd, f.base, &st, fstatat_flags) == 0) { current_mode = st.st_mode; current_mode_mask = all_mode_bits; if (S_ISDIR (current_mode)) { if (keep_directory_symlink_option && !fstatat_flags && issymlinkat (f.fd, f.base)) return true; if (interdir_made) { repair_delayed_set_stat (file_name, &st); return true; } break; } struct stat dirst; if (S_ISLNK (st.st_mode) && keep_directory_symlink_option && fstatat (f.fd, f.base, &dirst, 0) == 0 && S_ISDIR (dirst.st_mode)) return true; } } else if (update_interdir_set_stat (file_name)) return true; else if (old_files_option == UNLINK_FIRST_OLD_FILES) { status = 0; break; } errno = EEXIST; } switch (maybe_recoverable (file_name, false, &interdir_made)) { case RECOVER_OK: continue; case RECOVER_SKIP: break; case RECOVER_NO: if (errno != EEXIST) { mkdir_error (file_name); return false; } break; } break; } if (status == 0 || old_files_option == DEFAULT_OLD_FILES || old_files_option == OVERWRITE_OLD_FILES) delay_set_stat (file_name, ¤t_stat_info, current_mode, current_mode_mask, current_stat_info.stat.st_mode, atflag); return status == 0; } static int open_output_file (char const *file_name, char typeflag, mode_t mode, int file_created, mode_t *current_mode, mode_t *current_mode_mask) { int fd; bool overwriting_old_files = old_files_option == OVERWRITE_OLD_FILES; int openflag = (O_WRONLY | O_BINARY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK | (file_created ? O_NOFOLLOW : (O_CREAT | (overwriting_old_files ? O_TRUNC | (dereference_option ? 0 : O_NOFOLLOW) : O_EXCL)))); if (typeflag == CONTTYPE) { static bool conttype_diagnosed; if (!conttype_diagnosed) { conttype_diagnosed = true; warnopt (WARN_CONTIGUOUS_CAST, 0, _("Extracting contiguous files as regular files")); } } struct fdbase f = fdbase (file_name); /* If O_NOFOLLOW is needed but does not work, check for a symlink separately. There's a race condition, but that cannot be avoided on hosts lacking O_NOFOLLOW. */ if (! HAVE_WORKING_O_NOFOLLOW && overwriting_old_files && ! dereference_option && f.fd != BADFD && issymlinkat (f.fd, f.base)) { errno = ELOOP; return -1; } fd = f.fd == BADFD ? -1 : openat (f.fd, f.base, openflag, mode); if (0 <= fd) { if (openflag & O_EXCL) { *current_mode = mode & ~ current_umask; *current_mode_mask = MODE_RWX; } else { struct stat st; if (fstat (fd, &st) < 0) { int e = errno; close (fd); errno = e; return -1; } if (! S_ISREG (st.st_mode)) { close (fd); errno = EEXIST; return -1; } *current_mode = st.st_mode; *current_mode_mask = all_mode_bits; } } return fd; } static bool extract_file (char *file_name, char typeflag) { int fd; off_t size; union block *data_block; int status; bool interdir_made = false; mode_t mode = (current_stat_info.stat.st_mode & MODE_RWX & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0)); mode_t current_mode = 0; mode_t current_mode_mask = 0; if (to_stdout_option) fd = STDOUT_FILENO; else if (to_command_option) { fd = sys_exec_command (file_name, 'f', ¤t_stat_info); if (fd < 0) return true; } else { int file_created; /* Either we pre-create the file in set_xattr(), or we just directly open the file in open_output_file() with O_CREAT. If pre-creating, we need to use S_IWUSR so we can open the file O_WRONLY in open_output_file(). The additional mode bit is cleared later by set_stat()->set_mode(). */ while (((file_created = set_xattr (file_name, ¤t_stat_info, mode | S_IWUSR, typeflag)) < 0) || ((fd = open_output_file (file_name, typeflag, mode, file_created, ¤t_mode, ¤t_mode_mask)) < 0)) { enum recover recover = maybe_recoverable (file_name, true, &interdir_made); if (recover != RECOVER_OK) { if (recover == RECOVER_SKIP) return true; open_error (file_name); return false; } } } mv_begin_read (¤t_stat_info); if (current_stat_info.is_sparse) sparse_extract_file (fd, ¤t_stat_info, &size); else for (size = current_stat_info.stat.st_size; size > 0; ) { mv_size_left (size); /* Locate data, determine max length writeable, write it, block that we have used the data, then check if the write worked. */ data_block = find_next_block (); if (! data_block) { paxerror (0, _("Unexpected EOF in archive")); break; /* FIXME: What happens, then? */ } idx_t written = available_space_after (data_block); if (written > size) written = size; errno = 0; idx_t count = blocking_write (fd, charptr (data_block), written); size -= written; set_next_block_after (charptr (data_block) + written - 1); if (count != written) { if (!to_command_option) write_error_details (file_name, count, written); /* FIXME: shouldn't we restore from backup? */ break; } } skim_file (size, false); current_stat_info.skipped = true; mv_end (); /* If writing to stdout, don't try to do anything to the filename; it doesn't exist, or we don't want to touch it anyway. */ if (to_stdout_option) return true; if (! to_command_option) set_stat (file_name, ¤t_stat_info, fd, current_mode, current_mode_mask, typeflag, false, (old_files_option == OVERWRITE_OLD_FILES ? 0 : AT_SYMLINK_NOFOLLOW)); status = close (fd); if (status < 0) close_error (file_name); if (to_command_option) sys_wait_command (); return status == 0; } /* Return true if NAME is a delayed link. This can happen only if the link placeholder file has been created. Therefore, try to stat the NAME first. If it doesn't exist, there is no matching entry in the table. Otherwise, look for the entry in the table that has the matching dev and ino numbers. Return false if not found. Do not rely on comparing file names, which may differ for various reasons (e.g., relative vs. absolute file names). */ static bool find_delayed_link_source (char const *name) { struct stat st; if (!delayed_link_table) return false; struct fdbase f = fdbase (name); if (f.fd == BADFD || fstatat (f.fd, f.base, &st, AT_SYMLINK_NOFOLLOW) < 0) { if (errno != ENOENT) stat_error (name); return false; } struct delayed_link dl; dl.st_dev = st.st_dev; dl.st_ino = st.st_ino; return hash_lookup (delayed_link_table, &dl) != NULL; } /* Create a placeholder file with name FILE_NAME, which will be replaced after other extraction is done by a symbolic link if IS_SYMLINK is true, and by a hard link otherwise. Set *INTERDIR_MADE if an intermediate directory is made in the process. */ static bool create_placeholder_file (char *file_name, bool is_symlink, bool *interdir_made) { int fd; struct stat st; for (;;) { struct fdbase f = fdbase (file_name); if (f.fd != BADFD) { fd = openat (f.fd, f.base, O_WRONLY | O_CREAT | O_EXCL, 0); if (0 <= fd) break; } if (errno == EEXIST && find_delayed_link_source (file_name)) { /* The placeholder file has already been created. This means that the link being extracted is a duplicate of an already processed one. Skip it. */ return true; } switch (maybe_recoverable (file_name, false, interdir_made)) { case RECOVER_OK: continue; case RECOVER_SKIP: return true; case RECOVER_NO: open_error (file_name); return false; } } if (fstat (fd, &st) < 0) { stat_error (file_name); close (fd); } else if (close (fd) < 0) close_error (file_name); else { struct delayed_set_stat *h; struct delayed_link *p = xmalloc (FLEXNSIZEOF (struct delayed_link, target, strlen (current_stat_info.link_name) + 1)); p->next = NULL; p->st_dev = st.st_dev; p->st_ino = st.st_ino; #if HAVE_BIRTHTIME p->birthtime = get_stat_birthtime (&st); #endif p->is_symlink = is_symlink; if (is_symlink) { p->mode = current_stat_info.stat.st_mode; p->uid = current_stat_info.stat.st_uid; p->gid = current_stat_info.stat.st_gid; p->atime = current_stat_info.atime; p->mtime = current_stat_info.mtime; } p->change_dir = chdir_current; p->sources = xmalloc (FLEXNSIZEOF (struct string_list, string, strlen (file_name) + 1)); p->sources->next = NULL; strcpy (p->sources->string, file_name); p->cntx_name = NULL; assign_string_or_null (&p->cntx_name, current_stat_info.cntx_name); p->acls_a_ptr = NULL; p->acls_a_len = 0; p->acls_d_ptr = NULL; p->acls_d_len = 0; xattr_map_init (&p->xattr_map); xattr_map_copy (&p->xattr_map, ¤t_stat_info.xattr_map); strcpy (p->target, current_stat_info.link_name); *delayed_link_tail = p; delayed_link_tail = &p->next; if (! ((delayed_link_table || (delayed_link_table = hash_initialize (0, NULL, dl_hash, dl_compare, free))) && hash_insert (delayed_link_table, p))) xalloc_die (); if ((h = find_direct_ancestor (file_name)) != NULL) mark_metadata_set (h); return true; } return false; } static bool extract_link (char *file_name, char UNNAMED (typeflag)) { bool interdir_made = false; char const *link_name; enum recover rc; link_name = current_stat_info.link_name; if (absolute_names_option | dereference_option && ((! absolute_names_option && contains_dot_dot (link_name)) || find_delayed_link_source (link_name))) return create_placeholder_file (file_name, false, &interdir_made); do { struct stat st, st1; int status; struct fdbase f = fdbase (file_name), f1; if (f.fd == BADFD) status = -1; else { f1 = fdbase1 (link_name); status = (f1.fd == BADFD ? -1 : linkat (f1.fd, f1.base, f.fd, f.base, 0)); } if (status == 0) { if (delayed_link_table && fstatat (f1.fd, f1.base, &st1, AT_SYMLINK_NOFOLLOW) == 0) { struct delayed_link dl1; dl1.st_ino = st1.st_ino; dl1.st_dev = st1.st_dev; struct delayed_link *ds = hash_lookup (delayed_link_table, &dl1); if (ds && ds->change_dir == chdir_current && BIRTHTIME_EQ (ds->birthtime, get_stat_birthtime (&st1))) { struct string_list *p = xmalloc (FLEXNSIZEOF (struct string_list, string, strlen (file_name) + 1)); strcpy (p->string, file_name); p->next = ds->sources; ds->sources = p; } } return true; } int e = errno; if ((e == EEXIST && streq (link_name, file_name)) || (f.fd != BADFD && f1.fd != BADFD && fstatat (f1.fd, f1.base, &st1, AT_SYMLINK_NOFOLLOW) == 0 && fstatat (f.fd, f.base, &st, AT_SYMLINK_NOFOLLOW) == 0 && psame_inode (&st1, &st))) return true; errno = e; } while ((rc = maybe_recoverable (file_name, false, &interdir_made)) == RECOVER_OK); if (rc == RECOVER_SKIP) return true; if (!(incremental_option && errno == EEXIST)) { link_error (link_name, file_name); return false; } return true; } static bool extract_symlink (char *file_name, char typeflag) { bool interdir_made = false; if (!absolute_names_option & dereference_option && (IS_ABSOLUTE_FILE_NAME (current_stat_info.link_name) || contains_dot_dot (current_stat_info.link_name))) return create_placeholder_file (file_name, true, &interdir_made); for (struct fdbase f; ((f = fdbase (file_name)).fd == BADFD || symlinkat (current_stat_info.link_name, f.fd, f.base) < 0); ) switch (maybe_recoverable (file_name, false, &interdir_made)) { case RECOVER_OK: continue; case RECOVER_SKIP: return true; case RECOVER_NO: if (!implemented (errno)) { static bool warned; if (!warned) { warned = true; warnopt (WARN_SYMLINK_CAST, 0, _("Attempting extraction of symbolic links" " as hard links")); } return extract_link (file_name, typeflag); } symlink_error (current_stat_info.link_name, file_name); return false; } set_stat (file_name, ¤t_stat_info, -1, 0, 0, SYMTYPE, false, AT_SYMLINK_NOFOLLOW); return true; } #if S_IFCHR || S_IFBLK static bool extract_node (char *file_name, char typeflag) { bool interdir_made = false; mode_t mode = (current_stat_info.stat.st_mode & (MODE_RWX | S_IFBLK | S_IFCHR) & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0)); for (struct fdbase f; ((f = fdbase (file_name)).fd == BADFD || mknodat (f.fd, f.base, mode, current_stat_info.stat.st_rdev) < 0); ) switch (maybe_recoverable (file_name, false, &interdir_made)) { case RECOVER_OK: continue; case RECOVER_SKIP: return true; case RECOVER_NO: mknod_error (file_name); return false; } set_stat (file_name, ¤t_stat_info, -1, mode & ~ current_umask, MODE_RWX, typeflag, false, AT_SYMLINK_NOFOLLOW); return true; } #endif #if HAVE_MKFIFO || defined mkfifo static bool extract_fifo (char *file_name, char typeflag) { bool interdir_made = false; mode_t mode = (current_stat_info.stat.st_mode & MODE_RWX & ~ (0 < same_owner_option ? S_IRWXG | S_IRWXO : 0)); for (struct fdbase f; ((f = fdbase (file_name)).fd == BADFD || mkfifoat (f.fd, f.base, mode) < 0); ) switch (maybe_recoverable (file_name, false, &interdir_made)) { case RECOVER_OK: continue; case RECOVER_SKIP: return true; case RECOVER_NO: mkfifo_error (file_name); return false; } set_stat (file_name, ¤t_stat_info, -1, mode & ~ current_umask, MODE_RWX, typeflag, false, AT_SYMLINK_NOFOLLOW); return true; } #endif typedef bool (*tar_extractor_t) (char *file_name, char typeflag); /* Prepare to extract a file. Find extractor function. Return an extractor to proceed with the extraction, a null pointer to skip the current member. */ static tar_extractor_t prepare_to_extract (char const *file_name, char typeflag) { tar_extractor_t extractor; /* Select the extractor */ switch (typeflag) { case GNUTYPE_SPARSE: extractor = extract_file; break; case AREGTYPE: case REGTYPE: case CONTTYPE: /* Appears to be a file. But BSD tar uses the convention that a slash suffix means a directory. */ extractor = (current_stat_info.had_trailing_slash ? extract_dir : extract_file); break; case SYMTYPE: extractor = extract_symlink; break; case LNKTYPE: extractor = extract_link; break; #if S_IFCHR case CHRTYPE: current_stat_info.stat.st_mode |= S_IFCHR; extractor = extract_node; break; #endif #if S_IFBLK case BLKTYPE: current_stat_info.stat.st_mode |= S_IFBLK; extractor = extract_node; break; #endif #if HAVE_MKFIFO || defined mkfifo case FIFOTYPE: extractor = extract_fifo; break; #endif case DIRTYPE: case GNUTYPE_DUMPDIR: extractor = extract_dir; if (current_stat_info.is_dumpdir) delay_directory_restore_option = true; break; case GNUTYPE_VOLHDR: return NULL; case GNUTYPE_MULTIVOL: paxerror (0, _("%s: Cannot extract -- file is continued from another volume"), quotearg_colon (current_stat_info.file_name)); return NULL; case GNUTYPE_LONGNAME: case GNUTYPE_LONGLINK: paxerror (0, _("Unexpected long name header")); return NULL; default: warnopt (WARN_UNKNOWN_CAST, 0, _("%s: Unknown file type '%c', extracted as normal file"), quotearg_colon (file_name), typeflag); extractor = extract_file; } if (to_stdout_option || to_command_option) { if (extractor != extract_file) return NULL; } else { switch (old_files_option) { case UNLINK_FIRST_OLD_FILES: if (!remove_any_file (file_name, recursive_unlink_option ? RECURSIVE_REMOVE_OPTION : ORDINARY_REMOVE_OPTION) && errno && errno != ENOENT) { unlink_error (file_name); return NULL; } break; case KEEP_NEWER_FILES: if (file_newer_p (file_name, NULL, ¤t_stat_info)) { warnopt (WARN_IGNORE_NEWER, 0, _("Current %s is newer or same age"), quote (file_name)); return NULL; } break; default: break; } } return extractor; } /* Extract a file from the archive. */ void extract_archive (void) { char typeflag; fatal_exit_hook = extract_finish; set_next_block_after (current_header); if (!current_stat_info.file_name[0] || (interactive_option && !confirm ("extract", current_stat_info.file_name))) { skip_member (); return; } /* Print the block from current_header and current_stat. */ if (verbose_option) print_header (¤t_stat_info, current_header, -1); /* Restore stats for all non-ancestor directories, unless it is an incremental archive. (see NOTICE in the comment to delay_set_stat above) */ if (!delay_directory_restore_option) { idx_t dir = chdir_current; apply_nonancestor_delayed_set_stat (current_stat_info.file_name, false); chdir_do (dir, false); } /* Take a safety backup of a previously existing file. */ if (backup_option) if (!maybe_backup_file (current_stat_info.file_name, 0)) { paxerror (errno, _("%s: Was unable to backup this file"), quotearg_colon (current_stat_info.file_name)); skip_member (); return; } /* Extract the archive entry according to its type. */ /* KLUDGE */ typeflag = (sparse_member_p (¤t_stat_info) ? GNUTYPE_SPARSE : current_header->header.typeflag); tar_extractor_t fun = prepare_to_extract (current_stat_info.file_name, typeflag); bool ok = false; if (fun) { if (one_top_level_dir) { /* Create one_top_level dir if it does not exist. */ chdir_do (chdir_current, true); /* Flush delayed stat to mirror the code above that does it before extracting a new entry. Creating the one_top_level dir may have created new delayed_set_stat interdir entries, so repeat the operation. Ideally this should not be needed, but the newly-created interdir entries have st_dev/st_ino uninitialized, which would be a problem if there is a "." entry afterwards: apply_nonancestor_delayed_set_stat would use the uninitialized values. Ideally, st_dev/st_ino would be initialized by mark_metadata_set, but this one does not take chdir into account, so it stats a wrong file. */ if (!delay_directory_restore_option) { idx_t dir = chdir_current; apply_nonancestor_delayed_set_stat (current_stat_info.file_name, false); chdir_do (dir, false); } } if (fun (current_stat_info.file_name, typeflag)) ok = true; } skip_member (); if (!ok && backup_option) undo_last_backup (); } /* Extract the link DS whose final extraction was delayed. */ static void apply_delayed_link (struct delayed_link *ds) { char const *valid_source = NULL; chdir_do (ds->change_dir, false); for (struct string_list *sources = ds->sources; sources; sources = sources->next) { char const *source = sources->string; struct stat st; /* Make sure the placeholder file is still there. If not, don't create a link, as the placeholder was probably removed by a later extraction. */ struct fdbase f = fdbase (source); if (f.fd != BADFD && fstatat (f.fd, f.base, &st, AT_SYMLINK_NOFOLLOW) == 0 && SAME_INODE (st, *ds) && BIRTHTIME_EQ (get_stat_birthtime (&st), ds->birthtime)) { /* Unlink the placeholder, then create a hard link if possible, a symbolic link otherwise. */ struct fdbase f1; if (unlinkat (f.fd, f.base, 0) < 0) unlink_error (source); else if (valid_source && ((f1 = f.fd == BADFD ? f : fdbase1 (valid_source)).fd != BADFD) && linkat (f1.fd, f1.base, f.fd, f.base, 0) == 0) ; else if (!ds->is_symlink) { f1 = f.fd == BADFD ? f : fdbase1 (ds->target); if (f1.fd == BADFD || linkat (f1.fd, f1.base, f.fd, f.base, 0) < 0) link_error (ds->target, source); } else if (symlinkat (ds->target, f.fd, f.base) < 0) symlink_error (ds->target, source); else { struct tar_stat_info st1; st1.stat.st_mode = ds->mode; st1.stat.st_uid = ds->uid; st1.stat.st_gid = ds->gid; st1.atime = ds->atime; st1.mtime = ds->mtime; st1.cntx_name = ds->cntx_name; st1.acls_a_ptr = ds->acls_a_ptr; st1.acls_a_len = ds->acls_a_len; st1.acls_d_ptr = ds->acls_d_ptr; st1.acls_d_len = ds->acls_d_len; st1.xattr_map = ds->xattr_map; set_stat (source, &st1, -1, 0, 0, SYMTYPE, false, AT_SYMLINK_NOFOLLOW); valid_source = source; } } } /* There is little point to freeing, as we are about to exit, and freeing is more likely to cause than cure trouble. */ if (false) { for (struct string_list *sources = ds->sources; sources; ) { struct string_list *next = sources->next; free (sources); sources = next; } xattr_map_free (&ds->xattr_map); free (ds->cntx_name); } } /* Extract the links whose final extraction were delayed. */ static void apply_delayed_links (void) { for (struct delayed_link *ds = delayed_link_head; ds; ds = ds->next) apply_delayed_link (ds); if (false && delayed_link_table) { /* There is little point to freeing, as we are about to exit, and freeing is more likely to cause than cure trouble. Also, the above code has not bothered to free the list in delayed_link_head. */ hash_free (delayed_link_table); delayed_link_table = NULL; } } /* Finish the extraction of an archive. */ void extract_finish (void) { /* First, fix the status of ordinary directories that need fixing. */ apply_nonancestor_delayed_set_stat ("", false); /* Then, apply delayed links, so that they don't affect delayed directory status-setting for ordinary directories. */ apply_delayed_links (); /* Finally, fix the status of directories that are ancestors of delayed links. */ apply_nonancestor_delayed_set_stat ("", true); /* This table should be empty after apply_nonancestor_delayed_set_stat. */ if (false && delayed_set_stat_table) { /* There is little point to freeing, as we are about to exit, and freeing is more likely to cause than cure trouble. */ hash_free (delayed_set_stat_table); delayed_set_stat_table = NULL; } } bool rename_directory (char *src, char *dst) { struct fdbase f = fdbase (src); struct fdbase f1 = f.fd == BADFD ? f : fdbase1 (dst); if (f1.fd != BADFD && renameat (f.fd, f.base, f1.fd, f1.base) == 0) { fdbase_clear (); fixup_delayed_set_stat (src, dst); } else if (f.fd != BADFD) { int e = errno; switch (e) { case ENOENT: if (0 <= make_directories (dst, MAKEDIR_PARENT)) { /* make_directories likely cached DST and evicted SRC, so try to reuse the cached DST and then reget SRC. */ f = fdbase (dst); f1 = f.fd == BADFD ? f : fdbase1 (src); if (f1.fd != BADFD && renameat (f1.fd, f1.base, f.fd, f.base) == 0) { fdbase_clear (); return true; } e = errno; } break; case EXDEV: /* FIXME: Fall back to recursive copying */ default: break; } paxerror (e, _("Cannot rename %s to %s"), quote_n (0, src), quote_n (1, dst)); return false; } return true; }