/* copy.c -- core functions for copying files and directories Copyright (C) 89, 90, 91, 1995-2007 Free Software Foundation. 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 3, 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. */ /* Extracted from cp.c and librarified by Jim Meyering. */ #include #include #include #include #include #if HAVE_HURD_H # include #endif #if HAVE_PRIV_H # include #endif #include "system.h" #include "acl.h" #include "backupfile.h" #include "buffer-lcm.h" #include "canonicalize.h" #include "copy.h" #include "cp-hash.h" #include "euidaccess.h" #include "error.h" #include "fcntl--.h" #include "filemode.h" #include "filenamecat.h" #include "full-write.h" #include "getpagesize.h" #include "hash.h" #include "hash-pjw.h" #include "lchmod.h" #include "quote.h" #include "same.h" #include "savedir.h" #include "stat-time.h" #include "utimecmp.h" #include "utimens.h" #include "write-any-file.h" #include "mreadlink.h" #include "yesno.h" #ifndef HAVE_FCHOWN # define HAVE_FCHOWN false # define fchown(fd, uid, gid) (-1) #endif #ifndef HAVE_LCHOWN # define HAVE_LCHOWN false # define lchown(name, uid, gid) chown (name, uid, gid) #endif #define SAME_OWNER(A, B) ((A).st_uid == (B).st_uid) #define SAME_GROUP(A, B) ((A).st_gid == (B).st_gid) #define SAME_OWNER_AND_GROUP(A, B) (SAME_OWNER (A, B) && SAME_GROUP (A, B)) struct dir_list { struct dir_list *parent; ino_t ino; dev_t dev; }; /* Describe a just-created or just-renamed destination file. */ struct F_triple { char *name; ino_t st_ino; dev_t st_dev; }; /* Initial size of the above hash table. */ #define DEST_INFO_INITIAL_CAPACITY 61 static bool copy_internal (char const *src_name, char const *dst_name, bool new_dst, dev_t device, struct dir_list *ancestors, const struct cp_options *x, bool command_line_arg, bool *copy_into_self, bool *rename_succeeded); /* Pointers to the file names: they're used in the diagnostic that is issued when we detect the user is trying to copy a directory into itself. */ static char const *top_level_src_name; static char const *top_level_dst_name; /* The invocation name of this program. */ extern char *program_name; /* FIXME: describe */ /* FIXME: rewrite this to use a hash table so we avoid the quadratic performance hit that's probably noticeable only on trees deeper than a few hundred levels. See use of active_dir_map in remove.c */ static bool is_ancestor (const struct stat *sb, const struct dir_list *ancestors) { while (ancestors != 0) { if (ancestors->ino == sb->st_ino && ancestors->dev == sb->st_dev) return true; ancestors = ancestors->parent; } return false; } /* Read the contents of the directory SRC_NAME_IN, and recursively copy the contents to DST_NAME_IN. NEW_DST is true if DST_NAME_IN is a directory that was created previously in the recursion. SRC_SB and ANCESTORS describe SRC_NAME_IN. Set *COPY_INTO_SELF if SRC_NAME_IN is a parent of (or the same as) DST_NAME_IN; otherwise, clear it. Return true if successful. */ static bool copy_dir (char const *src_name_in, char const *dst_name_in, bool new_dst, const struct stat *src_sb, struct dir_list *ancestors, const struct cp_options *x, bool *copy_into_self) { char *name_space; char *namep; struct cp_options non_command_line_options = *x; bool ok = true; name_space = savedir (src_name_in); if (name_space == NULL) { /* This diagnostic is a bit vague because savedir can fail in several different ways. */ error (0, errno, _("cannot access %s"), quote (src_name_in)); return false; } /* For cp's -H option, dereference command line arguments, but do not dereference symlinks that are found via recursive traversal. */ if (x->dereference == DEREF_COMMAND_LINE_ARGUMENTS) non_command_line_options.dereference = DEREF_NEVER; namep = name_space; while (*namep != '\0') { bool local_copy_into_self; char *src_name = file_name_concat (src_name_in, namep, NULL); char *dst_name = file_name_concat (dst_name_in, namep, NULL); ok &= copy_internal (src_name, dst_name, new_dst, src_sb->st_dev, ancestors, &non_command_line_options, false, &local_copy_into_self, NULL); *copy_into_self |= local_copy_into_self; free (dst_name); free (src_name); namep += strlen (namep) + 1; } free (name_space); return ok; } /* Set the owner and owning group of DEST_DESC to the st_uid and st_gid fields of SRC_SB. If DEST_DESC is undefined (-1), set the owner and owning group of DST_NAME instead; for safety prefer lchown if the system supports it since no symbolic links should be involved. DEST_DESC must refer to the same file as DEST_NAME if defined. Return 1 if the syscall succeeds, 0 if it fails but it's OK not to preserve ownership, -1 otherwise. */ static int set_owner (const struct cp_options *x, char const *dst_name, int dest_desc, uid_t uid, gid_t gid) { if (HAVE_FCHOWN && dest_desc != -1) { if (fchown (dest_desc, uid, gid) == 0) return 1; } else { if (lchown (dst_name, uid, gid) == 0) return 1; } if (! chown_failure_ok (x)) { error (0, errno, _("failed to preserve ownership for %s"), quote (dst_name)); if (x->require_preserve) return -1; } return 0; } /* Set the st_author field of DEST_DESC to the st_author field of SRC_SB. If DEST_DESC is undefined (-1), set the st_author field of DST_NAME instead. DEST_DESC must refer to the same file as DEST_NAME if defined. */ static void set_author (const char *dst_name, int dest_desc, const struct stat *src_sb) { #if HAVE_STRUCT_STAT_ST_AUTHOR /* FIXME: Modify the following code so that it does not follow symbolic links. */ /* Preserve the st_author field. */ file_t file = (dest_desc < 0 ? file_name_lookup (dst_name, 0, 0) : getdport (dest_desc)); if (file == MACH_PORT_NULL) error (0, errno, _("failed to lookup file %s"), quote (dst_name)); else { error_t err = file_chauthor (file, src_sb->st_author); if (err) error (0, err, _("failed to preserve authorship for %s"), quote (dst_name)); mach_port_deallocate (mach_task_self (), file); } #endif } /* Change the file mode bits of the file identified by DESC or NAME to MODE. Use DESC if DESC is valid and fchmod is available, NAME otherwise. */ static int fchmod_or_lchmod (int desc, char const *name, mode_t mode) { #if HAVE_FCHMOD if (0 <= desc) return fchmod (desc, mode); #endif return lchmod (name, mode); } /* Copy a regular file from SRC_NAME to DST_NAME. If the source file contains holes, copies holes and blocks of zeros in the source file as holes in the destination file. (Holes are read as zeroes by the `read' system call.) When creating the destination, use DST_MODE & ~OMITTED_PERMISSIONS as the third argument in the call to open, adding OMITTED_PERMISSIONS after copying as needed. X provides many option settings. Return true if successful. *NEW_DST is as in copy_internal. SRC_SB is the result of calling XSTAT (aka stat) on SRC_NAME. */ static bool copy_reg (char const *src_name, char const *dst_name, const struct cp_options *x, mode_t dst_mode, mode_t omitted_permissions, bool *new_dst, struct stat const *src_sb) { char *buf; char *buf_alloc = NULL; char *name_alloc = NULL; char const *followed_dest_name = dst_name; int dest_desc; int dest_errno; int source_desc; mode_t src_mode = src_sb->st_mode; struct stat sb; struct stat src_open_sb; bool return_val = true; source_desc = open (src_name, (O_RDONLY | O_BINARY | (x->dereference == DEREF_NEVER ? O_NOFOLLOW : 0))); if (source_desc < 0) { error (0, errno, _("cannot open %s for reading"), quote (src_name)); return false; } if (fstat (source_desc, &src_open_sb) != 0) { error (0, errno, _("cannot fstat %s"), quote (src_name)); return_val = false; goto close_src_desc; } /* Compare the source dev/ino from the open file to the incoming, saved ones obtained via a previous call to stat. */ if (! SAME_INODE (*src_sb, src_open_sb)) { error (0, 0, _("skipping file %s, as it was replaced while being copied"), quote (src_name)); return_val = false; goto close_src_desc; } /* The semantics of the following open calls are mandated by the specs for both cp and mv. */ if (! *new_dst) { dest_desc = open (dst_name, O_WRONLY | O_TRUNC | O_BINARY); dest_errno = errno; /* When using cp --preserve=context to copy to an existing destination, use the default context rather than that of the source. Why? 1) the src context may prohibit writing, and 2) because it's more consistent to use the same context that is used when the destination file doesn't already exist. */ if (x->preserve_security_context && 0 <= dest_desc) { security_context_t con = NULL; if (getfscreatecon (&con) < 0) { error (0, errno, _("failed to get file system create context")); if (x->require_preserve_context) { return_val = false; goto close_src_desc; } } if (con) { if (fsetfilecon (dest_desc, con) < 0) { error (0, errno, _("failed to set the security context of %s to %s"), quote_n (0, dst_name), quote_n (1, con)); if (x->require_preserve_context) { return_val = false; freecon (con); goto close_src_desc; } } freecon(con); } } if (dest_desc < 0 && x->unlink_dest_after_failed_open) { if (unlink (dst_name) != 0) { error (0, errno, _("cannot remove %s"), quote (dst_name)); return_val = false; goto close_src_desc; } if (x->verbose) printf (_("removed %s\n"), quote (dst_name)); /* Tell caller that the destination file was unlinked. */ *new_dst = true; } } if (*new_dst) { int open_flags = O_WRONLY | O_CREAT | O_EXCL | O_BINARY; dest_desc = open (dst_name, open_flags, dst_mode & ~omitted_permissions); dest_errno = errno; /* When trying to copy through a dangling destination symlink, the above open fails with EEXIST. If that happens, and lstat'ing the DST_NAME shows that it is a symlink, repeat the open call, but this time with the name of the final, missing directory entry. */ if (dest_desc < 0 && dest_errno == EEXIST) { struct stat dangling_link_sb; if (lstat (dst_name, &dangling_link_sb) == 0 && S_ISLNK (dangling_link_sb.st_mode)) { /* FIXME: This is way overkill, since all that's needed is to follow the symlink that is the last file name component. */ name_alloc = canonicalize_filename_mode (dst_name, CAN_MISSING); if (name_alloc) { followed_dest_name = name_alloc; dest_desc = open (followed_dest_name, open_flags, dst_mode & ~omitted_permissions); dest_errno = errno; } } } } else omitted_permissions = 0; if (dest_desc < 0) { error (0, dest_errno, _("cannot create regular file %s"), quote (dst_name)); return_val = false; goto close_src_desc; } if (fstat (dest_desc, &sb) != 0) { error (0, errno, _("cannot fstat %s"), quote (dst_name)); return_val = false; goto close_src_and_dst_desc; } if (! (S_ISREG (src_open_sb.st_mode) && src_open_sb.st_size == 0)) { typedef uintptr_t word; off_t n_read_total = 0; /* Choose a suitable buffer size; it may be adjusted later. */ size_t buf_alignment = lcm (getpagesize (), sizeof (word)); size_t buf_alignment_slop = sizeof (word) + buf_alignment - 1; size_t buf_size = ST_BLKSIZE (sb); /* Deal with sparse files. */ bool last_write_made_hole = false; bool make_holes = false; if (S_ISREG (sb.st_mode)) { /* Even with --sparse=always, try to create holes only if the destination is a regular file. */ if (x->sparse_mode == SPARSE_ALWAYS) make_holes = true; #if HAVE_STRUCT_STAT_ST_BLOCKS /* Use a heuristic to determine whether SRC_NAME contains any sparse blocks. If the file has fewer blocks than would normally be needed for a file of its size, then at least one of the blocks in the file is a hole. */ if (x->sparse_mode == SPARSE_AUTO && S_ISREG (src_open_sb.st_mode) && ST_NBLOCKS (src_open_sb) < src_open_sb.st_size / ST_NBLOCKSIZE) make_holes = true; #endif } /* If not making a sparse file, try to use a more-efficient buffer size. */ if (! make_holes) { /* These days there's no point ever messing with buffers smaller than 8 KiB. It would be nice to configure SMALL_BUF_SIZE dynamically for this host and pair of files, but there doesn't seem to be a good way to get readahead info portably. */ enum { SMALL_BUF_SIZE = 8 * 1024 }; /* Compute the least common multiple of the input and output buffer sizes, adjusting for outlandish values. */ size_t blcm_max = MIN (SIZE_MAX, SSIZE_MAX) - buf_alignment_slop; size_t blcm = buffer_lcm (ST_BLKSIZE (src_open_sb), buf_size, blcm_max); /* Do not use a block size that is too small. */ buf_size = MAX (SMALL_BUF_SIZE, blcm); /* Do not bother with a buffer larger than the input file, plus one byte to make sure the file has not grown while reading it. */ if (S_ISREG (src_open_sb.st_mode) && src_open_sb.st_size < buf_size) buf_size = src_open_sb.st_size + 1; /* However, stick with a block size that is a positive multiple of blcm, overriding the above adjustments. Watch out for overflow. */ buf_size += blcm - 1; buf_size -= buf_size % blcm; if (buf_size == 0 || blcm_max < buf_size) buf_size = blcm; } /* Make a buffer with space for a sentinel at the end. */ buf_alloc = xmalloc (buf_size + buf_alignment_slop); buf = ptr_align (buf_alloc, buf_alignment); for (;;) { word *wp = NULL; ssize_t n_read = read (source_desc, buf, buf_size); if (n_read < 0) { #ifdef EINTR if (errno == EINTR) continue; #endif error (0, errno, _("reading %s"), quote (src_name)); return_val = false; goto close_src_and_dst_desc; } if (n_read == 0) break; n_read_total += n_read; if (make_holes) { char *cp; /* Sentinel to stop loop. */ buf[n_read] = '\1'; #ifdef lint /* Usually, buf[n_read] is not the byte just before a "word" (aka uintptr_t) boundary. In that case, the word-oriented test below (*wp++ == 0) would read some uninitialized bytes after the sentinel. To avoid false-positive reports about this condition (e.g., from a tool like valgrind), set the remaining bytes -- to any value. */ memset (buf + n_read + 1, 0, sizeof (word) - 1); #endif /* Find first nonzero *word*, or the word with the sentinel. */ wp = (word *) buf; while (*wp++ == 0) continue; /* Find the first nonzero *byte*, or the sentinel. */ cp = (char *) (wp - 1); while (*cp++ == 0) continue; if (cp <= buf + n_read) /* Clear to indicate that a normal write is needed. */ wp = NULL; else { /* We found the sentinel, so the whole input block was zero. Make a hole. */ if (lseek (dest_desc, n_read, SEEK_CUR) < 0) { error (0, errno, _("cannot lseek %s"), quote (dst_name)); return_val = false; goto close_src_and_dst_desc; } last_write_made_hole = true; } } if (!wp) { size_t n = n_read; if (full_write (dest_desc, buf, n) != n) { error (0, errno, _("writing %s"), quote (dst_name)); return_val = false; goto close_src_and_dst_desc; } last_write_made_hole = false; /* A short read on a regular file means EOF. */ if (n_read != buf_size && S_ISREG (src_open_sb.st_mode)) break; } } /* If the file ends with a `hole', we need to do something to record the length of the file. On modern systems, calling ftruncate does the job. On systems without native ftruncate support, we have to write a byte at the ending position. Otherwise the kernel would truncate the file at the end of the last write operation. */ if (last_write_made_hole) { if (HAVE_FTRUNCATE ? /* ftruncate sets the file size, so there is no need for a write. */ ftruncate (dest_desc, n_read_total) < 0 : /* Seek backwards one character and write a null. */ (lseek (dest_desc, (off_t) -1, SEEK_CUR) < 0L || full_write (dest_desc, "", 1) != 1)) { error (0, errno, _("writing %s"), quote (dst_name)); return_val = false; goto close_src_and_dst_desc; } } } if (x->preserve_timestamps) { struct timespec timespec[2]; timespec[0] = get_stat_atime (src_sb); timespec[1] = get_stat_mtime (src_sb); if (gl_futimens (dest_desc, followed_dest_name, timespec) != 0) { error (0, errno, _("preserving times for %s"), quote (dst_name)); if (x->require_preserve) { return_val = false; goto close_src_and_dst_desc; } } } if (x->preserve_ownership && ! SAME_OWNER_AND_GROUP (*src_sb, sb)) { switch (set_owner (x, followed_dest_name, dest_desc, src_sb->st_uid, src_sb->st_gid)) { case -1: return_val = false; goto close_src_and_dst_desc; case 0: src_mode &= ~ (S_ISUID | S_ISGID | S_ISVTX); break; } } set_author (followed_dest_name, dest_desc, src_sb); if (x->preserve_mode || x->move_mode) { if (copy_acl (src_name, source_desc, followed_dest_name, dest_desc, src_mode) != 0 && x->require_preserve) return_val = false; } else if (x->set_mode) { if (set_acl (followed_dest_name, dest_desc, x->mode) != 0) return_val = false; } else if (omitted_permissions) { omitted_permissions &= ~ cached_umask (); if (omitted_permissions && fchmod_or_lchmod (dest_desc, followed_dest_name, dst_mode) != 0) { error (0, errno, _("preserving permissions for %s"), quote (dst_name)); if (x->require_preserve) return_val = false; } } close_src_and_dst_desc: if (close (dest_desc) < 0) { error (0, errno, _("closing %s"), quote (dst_name)); return_val = false; } close_src_desc: if (close (source_desc) < 0) { error (0, errno, _("closing %s"), quote (src_name)); return_val = false; } free (buf_alloc); free (name_alloc); return return_val; } /* Return true if it's ok that the source and destination files are the `same' by some measure. The goal is to avoid making the `copy' operation remove both copies of the file in that case, while still allowing the user to e.g., move or copy a regular file onto a symlink that points to it. Try to minimize the cost of this function in the common case. Set *RETURN_NOW if we've determined that the caller has no more work to do and should return successfully, right away. Set *UNLINK_SRC if we've determined that the caller wants to do `rename (a, b)' where `a' and `b' are distinct hard links to the same file. In that case, the caller should try to unlink `a' and then return successfully. Ideally, we wouldn't have to do that, and we'd be able to rely on rename to remove the source file. However, POSIX mistakenly requires that such a rename call do *nothing* and return successfully. */ static bool same_file_ok (char const *src_name, struct stat const *src_sb, char const *dst_name, struct stat const *dst_sb, const struct cp_options *x, bool *return_now, bool *unlink_src) { const struct stat *src_sb_link; const struct stat *dst_sb_link; struct stat tmp_dst_sb; struct stat tmp_src_sb; bool same_link; bool same = SAME_INODE (*src_sb, *dst_sb); *return_now = false; *unlink_src = false; /* FIXME: this should (at the very least) be moved into the following if-block. More likely, it should be removed, because it inhibits making backups. But removing it will result in a change in behavior that will probably have to be documented -- and tests will have to be updated. */ if (same && x->hard_link) { *return_now = true; return true; } if (x->dereference == DEREF_NEVER) { same_link = same; /* If both the source and destination files are symlinks (and we'll know this here IFF preserving symlinks), then it's ok -- as long as they are distinct. */ if (S_ISLNK (src_sb->st_mode) && S_ISLNK (dst_sb->st_mode)) return ! same_name (src_name, dst_name); src_sb_link = src_sb; dst_sb_link = dst_sb; } else { if (!same) return true; if (lstat (dst_name, &tmp_dst_sb) != 0 || lstat (src_name, &tmp_src_sb) != 0) return true; src_sb_link = &tmp_src_sb; dst_sb_link = &tmp_dst_sb; same_link = SAME_INODE (*src_sb_link, *dst_sb_link); /* If both are symlinks, then it's ok, but only if the destination will be unlinked before being opened. This is like the test above, but with the addition of the unlink_dest_before_opening conjunct because otherwise, with two symlinks to the same target, we'd end up truncating the source file. */ if (S_ISLNK (src_sb_link->st_mode) && S_ISLNK (dst_sb_link->st_mode) && x->unlink_dest_before_opening) return true; } /* The backup code ensures there's a copy, so it's usually ok to remove any destination file. One exception is when both source and destination are the same directory entry. In that case, moving the destination file aside (in making the backup) would also rename the source file and result in an error. */ if (x->backup_type != no_backups) { if (!same_link) { /* In copy mode when dereferencing symlinks, if the source is a symlink and the dest is not, then backing up the destination (moving it aside) would make it a dangling symlink, and the subsequent attempt to open it in copy_reg would fail with a misleading diagnostic. Avoid that by returning zero in that case so the caller can make cp (or mv when it has to resort to reading the source file) fail now. */ /* FIXME-note: even with the following kludge, we can still provoke the offending diagnostic. It's just a little harder to do :-) $ rm -f a b c; touch c; ln -s c b; ln -s b a; cp -b a b cp: cannot open `a' for reading: No such file or directory That's misleading, since a subsequent `ls' shows that `a' is still there. One solution would be to open the source file *before* moving aside the destination, but that'd involve a big rewrite. */ if ( ! x->move_mode && x->dereference != DEREF_NEVER && S_ISLNK (src_sb_link->st_mode) && ! S_ISLNK (dst_sb_link->st_mode)) return false; return true; } return ! same_name (src_name, dst_name); } #if 0 /* FIXME: use or remove */ /* If we're making a backup, we'll detect the problem case in copy_reg because SRC_NAME will no longer exist. Allowing the test to be deferred lets cp do some useful things. But when creating hardlinks and SRC_NAME is a symlink but DST_NAME is not we must test anyway. */ if (x->hard_link || !S_ISLNK (src_sb_link->st_mode) || S_ISLNK (dst_sb_link->st_mode)) return true; if (x->dereference != DEREF_NEVER) return true; #endif /* They may refer to the same file if we're in move mode and the target is a symlink. That is ok, since we remove any existing destination file before opening it -- via `rename' if they're on the same file system, via `unlink (DST_NAME)' otherwise. It's also ok if they're distinct hard links to the same file. */ if (x->move_mode || x->unlink_dest_before_opening) { if (S_ISLNK (dst_sb_link->st_mode)) return true; if (same_link && 1 < dst_sb_link->st_nlink && ! same_name (src_name, dst_name)) { if (x->move_mode) { *unlink_src = true; *return_now = true; } return true; } } /* If neither is a symlink, then it's ok as long as they aren't hard links to the same file. */ if (!S_ISLNK (src_sb_link->st_mode) && !S_ISLNK (dst_sb_link->st_mode)) { if (!SAME_INODE (*src_sb_link, *dst_sb_link)) return true; /* If they are the same file, it's ok if we're making hard links. */ if (x->hard_link) { *return_now = true; return true; } } /* It's ok to remove a destination symlink. But that works only when we unlink before opening the destination and when the source and destination files are on the same partition. */ if (x->unlink_dest_before_opening && S_ISLNK (dst_sb_link->st_mode)) return dst_sb_link->st_dev == src_sb_link->st_dev; if (x->dereference == DEREF_NEVER) { if ( ! S_ISLNK (src_sb_link->st_mode)) tmp_src_sb = *src_sb_link; else if (stat (src_name, &tmp_src_sb) != 0) return true; if ( ! S_ISLNK (dst_sb_link->st_mode)) tmp_dst_sb = *dst_sb_link; else if (stat (dst_name, &tmp_dst_sb) != 0) return true; if ( ! SAME_INODE (tmp_src_sb, tmp_dst_sb)) return true; /* FIXME: shouldn't this be testing whether we're making symlinks? */ if (x->hard_link) { *return_now = true; return true; } } return false; } /* Return true if FILE, with mode MODE, is writable in the sense of 'mv'. Always consider a symbolic link to be writable. */ static bool writable_destination (char const *file, mode_t mode) { return (S_ISLNK (mode) || can_write_any_file () || euidaccess (file, W_OK) == 0); } static void overwrite_prompt (char const *dst_name, struct stat const *dst_sb) { if (! writable_destination (dst_name, dst_sb->st_mode)) { char perms[12]; /* "-rwxrwxrwx " ls-style modes. */ strmode (dst_sb->st_mode, perms); perms[10] = '\0'; fprintf (stderr, _("%s: try to overwrite %s, overriding mode %04lo (%s)? "), program_name, quote (dst_name), (unsigned long int) (dst_sb->st_mode & CHMOD_MODE_BITS), &perms[1]); } else { fprintf (stderr, _("%s: overwrite %s? "), program_name, quote (dst_name)); } } /* Hash an F_triple. */ static size_t triple_hash (void const *x, size_t table_size) { struct F_triple const *p = x; /* Also take the name into account, so that when moving N hard links to the same file (all listed on the command line) all into the same directory, we don't experience any N^2 behavior. */ /* FIXME-maybe: is it worth the overhead of doing this just to avoid N^2 in such an unusual case? N would have to be very large to make the N^2 factor noticable, and one would probably encounter a limit on the length of a command line before it became a problem. */ size_t tmp = hash_pjw (p->name, table_size); /* Ignoring the device number here should be fine. */ return (tmp | p->st_ino) % table_size; } /* Hash an F_triple. */ static size_t triple_hash_no_name (void const *x, size_t table_size) { struct F_triple const *p = x; /* Ignoring the device number here should be fine. */ return p->st_ino % table_size; } /* Compare two F_triple structs. */ static bool triple_compare (void const *x, void const *y) { struct F_triple const *a = x; struct F_triple const *b = y; return (SAME_INODE (*a, *b) && same_name (a->name, b->name)) ? true : false; } /* Free an F_triple. */ static void triple_free (void *x) { struct F_triple *a = x; free (a->name); free (a); } /* Initialize the hash table implementing a set of F_triple entries corresponding to destination files. */ extern void dest_info_init (struct cp_options *x) { x->dest_info = hash_initialize (DEST_INFO_INITIAL_CAPACITY, NULL, triple_hash, triple_compare, triple_free); } /* Initialize the hash table implementing a set of F_triple entries corresponding to source files listed on the command line. */ extern void src_info_init (struct cp_options *x) { /* Note that we use triple_hash_no_name here. Contrast with the use of triple_hash above. That is necessary because a source file may be specified in many different ways. We want to warn about this cp a a d/ as well as this: cp a ./a d/ */ x->src_info = hash_initialize (DEST_INFO_INITIAL_CAPACITY, NULL, triple_hash_no_name, triple_compare, triple_free); } /* Return true if there is an entry in hash table, HT, for the file described by FILE and STATS. */ static bool seen_file (Hash_table const *ht, char const *file, struct stat const *stats) { struct F_triple new_ent; if (ht == NULL) return false; new_ent.name = (char *) file; new_ent.st_ino = stats->st_ino; new_ent.st_dev = stats->st_dev; return !!hash_lookup (ht, &new_ent); } /* Record destination file, FILE, and dev/ino from *STATS, in the hash table, HT. If HT is NULL, return immediately. If STATS is NULL, call lstat on FILE to get the device and inode numbers. If that lstat fails, simply return. If memory allocation fails, exit immediately. */ static void record_file (Hash_table *ht, char const *file, struct stat const *stats) { struct F_triple *ent; if (ht == NULL) return; ent = xmalloc (sizeof *ent); ent->name = xstrdup (file); if (stats) { ent->st_ino = stats->st_ino; ent->st_dev = stats->st_dev; } else { struct stat sb; if (lstat (file, &sb) != 0) return; ent->st_ino = sb.st_ino; ent->st_dev = sb.st_dev; } { struct F_triple *ent_from_table = hash_insert (ht, ent); if (ent_from_table == NULL) { /* Insertion failed due to lack of memory. */ xalloc_die (); } if (ent_from_table != ent) { /* There was alread a matching entry in the table, so ENT was not inserted. Free it. */ triple_free (ent); } } } /* When effecting a move (e.g., for mv(1)), and given the name DST_NAME of the destination and a corresponding stat buffer, DST_SB, return true if the logical `move' operation should _not_ proceed. Otherwise, return false. Depending on options specified in X, this code may issue an interactive prompt asking whether it's ok to overwrite DST_NAME. */ static bool abandon_move (const struct cp_options *x, char const *dst_name, struct stat const *dst_sb) { assert (x->move_mode); return (x->interactive == I_ALWAYS_NO || ((x->interactive == I_ASK_USER || (x->interactive == I_UNSPECIFIED && x->stdin_tty && ! writable_destination (dst_name, dst_sb->st_mode))) && (overwrite_prompt (dst_name, dst_sb), 1) && ! yesno ())); } /* Print --verbose output on standard output, e.g. `new' -> `old'. If BACKUP_DST_NAME is non-NULL, then also indicate that it is the name of a backup file. */ static void emit_verbose (char const *src, char const *dst, char const *backup_dst_name) { printf ("%s -> %s", quote_n (0, src), quote_n (1, dst)); if (backup_dst_name) printf (_(" (backup: %s)"), quote (backup_dst_name)); putchar ('\n'); } /* A wrapper around "setfscreatecon (NULL)" that exits upon failure. */ static void restore_default_fscreatecon_or_die (void) { if (setfscreatecon (NULL) != 0) error (EXIT_FAILURE, errno, _("failed to restore the default file creation context")); } /* Copy the file SRC_NAME to the file DST_NAME. The files may be of any type. NEW_DST should be true if the file DST_NAME cannot exist because its parent directory was just created; NEW_DST should be false if DST_NAME might already exist. DEVICE is the device number of the parent directory, or 0 if the parent of this file is not known. ANCESTORS points to a linked, null terminated list of devices and inodes of parent directories of SRC_NAME. COMMAND_LINE_ARG is true iff SRC_NAME was specified on the command line. Set *COPY_INTO_SELF if SRC_NAME is a parent of (or the same as) DST_NAME; otherwise, clear it. Return true if successful. */ static bool copy_internal (char const *src_name, char const *dst_name, bool new_dst, dev_t device, struct dir_list *ancestors, const struct cp_options *x, bool command_line_arg, bool *copy_into_self, bool *rename_succeeded) { struct stat src_sb; struct stat dst_sb; mode_t src_mode; mode_t dst_mode IF_LINT (= 0); mode_t dst_mode_bits; mode_t omitted_permissions; bool restore_dst_mode = false; char *earlier_file = NULL; char *dst_backup = NULL; bool backup_succeeded = false; bool delayed_ok; bool copied_as_regular = false; bool preserve_metadata; if (x->move_mode && rename_succeeded) *rename_succeeded = false; *copy_into_self = false; if (XSTAT (x, src_name, &src_sb) != 0) { error (0, errno, _("cannot stat %s"), quote (src_name)); return false; } src_mode = src_sb.st_mode; if (S_ISDIR (src_mode) && !x->recursive) { error (0, 0, _("omitting directory %s"), quote (src_name)); return false; } /* Detect the case in which the same source file appears more than once on the command line and no backup option has been selected. If so, simply warn and don't copy it the second time. This check is enabled only if x->src_info is non-NULL. */ if (command_line_arg) { if ( ! S_ISDIR (src_sb.st_mode) && x->backup_type == no_backups && seen_file (x->src_info, src_name, &src_sb)) { error (0, 0, _("warning: source file %s specified more than once"), quote (src_name)); return true; } record_file (x->src_info, src_name, &src_sb); } if (!new_dst) { /* Regular files can be created by writing through symbolic links, but other files cannot. So use stat on the destination when copying a regular file, and lstat otherwise. However, if we intend to unlink or remove the destination first, use lstat, since a copy won't actually be made to the destination in that case. */ if ((((S_ISREG (src_mode) || (x->copy_as_regular && ! (S_ISDIR (src_mode) || S_ISLNK (src_mode)))) && ! (x->move_mode || x->symbolic_link || x->hard_link || x->backup_type != no_backups || x->unlink_dest_before_opening)) ? stat (dst_name, &dst_sb) : lstat (dst_name, &dst_sb)) != 0) { if (errno != ENOENT) { error (0, errno, _("cannot stat %s"), quote (dst_name)); return false; } else { new_dst = true; } } else { /* Here, we know that dst_name exists, at least to the point that it is stat'able or lstat'table. */ bool return_now; bool unlink_src; if (! same_file_ok (src_name, &src_sb, dst_name, &dst_sb, x, &return_now, &unlink_src)) { error (0, 0, _("%s and %s are the same file"), quote_n (0, src_name), quote_n (1, dst_name)); return false; } if (!S_ISDIR (src_mode) && x->update) { /* When preserving time stamps (but not moving within a file system), don't worry if the destination time stamp is less than the source merely because of time stamp truncation. */ int options = ((x->preserve_timestamps && ! (x->move_mode && dst_sb.st_dev == src_sb.st_dev)) ? UTIMECMP_TRUNCATE_SOURCE : 0); if (0 <= utimecmp (dst_name, &dst_sb, &src_sb, options)) { /* We're using --update and the destination is not older than the source, so do not copy or move. Pretend the rename succeeded, so the caller (if it's mv) doesn't end up removing the source file. */ if (rename_succeeded) *rename_succeeded = true; return true; } } /* When there is an existing destination file, we may end up returning early, and hence not copying/moving the file. This may be due to an interactive `negative' reply to the prompt about the existing file. It may also be due to the use of the --reply=no option. cp and mv treat -i and -f differently. */ if (x->move_mode) { if (abandon_move (x, dst_name, &dst_sb) || (unlink_src && unlink (src_name) == 0)) { /* Pretend the rename succeeded, so the caller (mv) doesn't end up removing the source file. */ if (rename_succeeded) *rename_succeeded = true; if (unlink_src && x->verbose) printf (_("removed %s\n"), quote (src_name)); return true; } if (unlink_src) { error (0, errno, _("cannot remove %s"), quote (src_name)); return false; } } else { if (! S_ISDIR (src_mode) && (x->interactive == I_ALWAYS_NO || (x->interactive == I_ASK_USER && (overwrite_prompt (dst_name, &dst_sb), 1) && ! yesno ()))) return true; } if (return_now) return true; if (!S_ISDIR (dst_sb.st_mode)) { if (S_ISDIR (src_mode)) { if (x->move_mode && x->backup_type != no_backups) { /* Moving a directory onto an existing non-directory is ok only with --backup. */ } else { error (0, 0, _("cannot overwrite non-directory %s with directory %s"), quote_n (0, dst_name), quote_n (1, src_name)); return false; } } /* Don't let the user destroy their data, even if they try hard: This mv command must fail (likewise for cp): rm -rf a b c; mkdir a b c; touch a/f b/f; mv a/f b/f c Otherwise, the contents of b/f would be lost. In the case of `cp', b/f would be lost if the user simulated a move using cp and rm. Note that it works fine if you use --backup=numbered. */ if (command_line_arg && x->backup_type != numbered_backups && seen_file (x->dest_info, dst_name, &dst_sb)) { error (0, 0, _("will not overwrite just-created %s with %s"), quote_n (0, dst_name), quote_n (1, src_name)); return false; } } if (!S_ISDIR (src_mode)) { if (S_ISDIR (dst_sb.st_mode)) { if (x->move_mode && x->backup_type != no_backups) { /* Moving a non-directory onto an existing directory is ok only with --backup. */ } else { error (0, 0, _("cannot overwrite directory %s with non-directory"), quote (dst_name)); return false; } } } if (x->move_mode) { /* Don't allow user to move a directory onto a non-directory. */ if (S_ISDIR (src_sb.st_mode) && !S_ISDIR (dst_sb.st_mode) && x->backup_type == no_backups) { error (0, 0, _("cannot move directory onto non-directory: %s -> %s"), quote_n (0, src_name), quote_n (0, dst_name)); return false; } } if (x->backup_type != no_backups /* Don't try to back up a destination if the last component of src_name is "." or "..". */ && ! dot_or_dotdot (last_component (src_name)) /* Create a backup of each destination directory in move mode, but not in copy mode. FIXME: it might make sense to add an option to suppress backup creation also for move mode. That would let one use mv to merge new content into an existing hierarchy. */ && (x->move_mode || ! S_ISDIR (dst_sb.st_mode))) { char *tmp_backup = find_backup_file_name (dst_name, x->backup_type); /* Detect (and fail) when creating the backup file would destroy the source file. Before, running the commands cd /tmp; rm -f a a~; : > a; echo A > a~; cp --b=simple a~ a would leave two zero-length files: a and a~. */ /* FIXME: but simply change e.g., the final a~ to `./a~' and the source will still be destroyed. */ if (STREQ (tmp_backup, src_name)) { const char *fmt; fmt = (x->move_mode ? _("backing up %s would destroy source; %s not moved") : _("backing up %s would destroy source; %s not copied")); error (0, 0, fmt, quote_n (0, dst_name), quote_n (1, src_name)); free (tmp_backup); return false; } /* FIXME: use fts: Using alloca for a file name that may be arbitrarily long is not recommended. In fact, even forming such a name should be discouraged. Eventually, this code will be rewritten to use fts, so using alloca here will be less of a problem. */ ASSIGN_STRDUPA (dst_backup, tmp_backup); free (tmp_backup); if (rename (dst_name, dst_backup) != 0) { if (errno != ENOENT) { error (0, errno, _("cannot backup %s"), quote (dst_name)); return false; } else { dst_backup = NULL; } } else { backup_succeeded = true; } new_dst = true; } else if (! S_ISDIR (dst_sb.st_mode) && (x->unlink_dest_before_opening || (x->preserve_links && 1 < dst_sb.st_nlink) || (!x->move_mode && x->dereference == DEREF_NEVER && S_ISLNK (src_sb.st_mode)) )) { if (unlink (dst_name) != 0 && errno != ENOENT) { error (0, errno, _("cannot remove %s"), quote (dst_name)); return false; } new_dst = true; if (x->verbose) printf (_("removed %s\n"), quote (dst_name)); } } } /* If the source is a directory, we don't always create the destination directory. So --verbose should not announce anything until we're sure we'll create a directory. */ if (x->verbose && !S_ISDIR (src_mode)) emit_verbose (src_name, dst_name, backup_succeeded ? dst_backup : NULL); /* Associate the destination file name with the source device and inode so that if we encounter a matching dev/ino pair in the source tree we can arrange to create a hard link between the corresponding names in the destination tree. Sometimes, when preserving links, we have to record dev/ino even though st_nlink == 1: - when in move_mode, since we may be moving a group of N hard-linked files (via two or more command line arguments) to a different partition; the links may be distributed among the command line arguments (possibly hierarchies) so that the link count of the final, once-linked source file is reduced to 1 when it is considered below. But in this case (for mv) we don't need to incur the expense of recording the dev/ino => name mapping; all we really need is a lookup, to see if the dev/ino pair has already been copied. - when using -H and processing a command line argument; that command line argument could be a symlink pointing to another command line argument. With `cp -H --preserve=link', we hard-link those two destination files. - likewise for -L except that it applies to all files, not just command line arguments. Also record directory dev/ino when using --recursive. We'll use that info to detect this problem: cp -R dir dir. FIXME-maybe: ideally, directory info would be recorded in a separate hash table, since such entries are useful only while a single command line hierarchy is being copied -- so that separate table could be cleared between command line args. Using the same hash table to preserve hard links means that it may not be cleared. */ if (x->move_mode && src_sb.st_nlink == 1) { earlier_file = src_to_dest_lookup (src_sb.st_ino, src_sb.st_dev); } else if ((x->preserve_links && (1 < src_sb.st_nlink || (command_line_arg && x->dereference == DEREF_COMMAND_LINE_ARGUMENTS) || x->dereference == DEREF_ALWAYS)) || (x->recursive && S_ISDIR (src_mode))) { earlier_file = remember_copied (dst_name, src_sb.st_ino, src_sb.st_dev); } /* Did we copy this inode somewhere else (in this command line argument) and therefore this is a second hard link to the inode? */ if (earlier_file) { /* Avoid damaging the destination file system by refusing to preserve hard-linked directories (which are found at least in Netapp snapshot directories). */ if (S_ISDIR (src_mode)) { /* If src_name and earlier_file refer to the same directory entry, then warn about copying a directory into itself. */ if (same_name (src_name, earlier_file)) { error (0, 0, _("cannot copy a directory, %s, into itself, %s"), quote_n (0, top_level_src_name), quote_n (1, top_level_dst_name)); *copy_into_self = true; goto un_backup; } else if (x->dereference == DEREF_ALWAYS) { /* This happens when e.g., encountering a directory for the second or subsequent time via symlinks when cp is invoked with -R and -L. E.g., rm -rf a b c d; mkdir a b c d; ln -s ../c a; ln -s ../c b; cp -RL a b d */ } else { error (0, 0, _("will not create hard link %s to directory %s"), quote_n (0, dst_name), quote_n (1, earlier_file)); goto un_backup; } } else { bool link_failed = (link (earlier_file, dst_name) != 0); /* If the link failed because of an existing destination, remove that file and then call link again. */ if (link_failed && errno == EEXIST) { if (unlink (dst_name) != 0) { error (0, errno, _("cannot remove %s"), quote (dst_name)); goto un_backup; } if (x->verbose) printf (_("removed %s\n"), quote (dst_name)); link_failed = (link (earlier_file, dst_name) != 0); } if (link_failed) { error (0, errno, _("cannot create hard link %s to %s"), quote_n (0, dst_name), quote_n (1, earlier_file)); goto un_backup; } return true; } } if (x->move_mode) { if (rename (src_name, dst_name) == 0) { if (x->verbose && S_ISDIR (src_mode)) emit_verbose (src_name, dst_name, backup_succeeded ? dst_backup : NULL); if (rename_succeeded) *rename_succeeded = true; if (command_line_arg) { /* Record destination dev/ino/name, so that if we are asked to overwrite that file again, we can detect it and fail. */ /* It's fine to use the _source_ stat buffer (src_sb) to get the _destination_ dev/ino, since the rename above can't have changed those, and `mv' always uses lstat. We could limit it further by operating only on non-directories. */ record_file (x->dest_info, dst_name, &src_sb); } return true; } /* FIXME: someday, consider what to do when moving a directory into itself but when source and destination are on different devices. */ /* This happens when attempting to rename a directory to a subdirectory of itself. */ if (errno == EINVAL) { /* FIXME: this is a little fragile in that it relies on rename(2) failing with a specific errno value. Expect problems on non-POSIX systems. */ error (0, 0, _("cannot move %s to a subdirectory of itself, %s"), quote_n (0, top_level_src_name), quote_n (1, top_level_dst_name)); /* Note that there is no need to call forget_created here, (compare with the other calls in this file) since the destination directory didn't exist before. */ *copy_into_self = true; /* FIXME-cleanup: Don't return true here; adjust mv.c accordingly. The only caller that uses this code (mv.c) ends up setting its exit status to nonzero when copy_into_self is nonzero. */ return true; } /* WARNING: there probably exist systems for which an inter-device rename fails with a value of errno not handled here. If/as those are reported, add them to the condition below. If this happens to you, please do the following and send the output to the bug-reporting address (e.g., in the output of cp --help): touch k; perl -e 'rename "k","/tmp/k" or print "$!(",$!+0,")\n"' where your current directory is on one partion and /tmp is the other. Also, please try to find the E* errno macro name corresponding to the diagnostic and parenthesized integer, and include that in your e-mail. One way to do that is to run a command like this find /usr/include/. -type f \ | xargs grep 'define.*\.*\<18\>' /dev/null where you'd replace `18' with the integer in parentheses that was output from the perl one-liner above. If necessary, of course, change `/tmp' to some other directory. */ if (errno != EXDEV) { /* There are many ways this can happen due to a race condition. When something happens between the initial XSTAT and the subsequent rename, we can get many different types of errors. For example, if the destination is initially a non-directory or non-existent, but it is created as a directory, the rename fails. If two `mv' commands try to rename the same file at about the same time, one will succeed and the other will fail. If the permissions on the directory containing the source or destination file are made too restrictive, the rename will fail. Etc. */ error (0, errno, _("cannot move %s to %s"), quote_n (0, src_name), quote_n (1, dst_name)); forget_created (src_sb.st_ino, src_sb.st_dev); return false; } /* The rename attempt has failed. Remove any existing destination file so that a cross-device `mv' acts as if it were really using the rename syscall. */ if (unlink (dst_name) != 0 && errno != ENOENT) { error (0, errno, _("inter-device move failed: %s to %s; unable to remove target"), quote_n (0, src_name), quote_n (1, dst_name)); forget_created (src_sb.st_ino, src_sb.st_dev); return false; } new_dst = true; } /* If the ownership might change, or if it is a directory (whose special mode bits may change after the directory is created), omit some permissions at first, so unauthorized users cannot nip in before the file is ready. */ dst_mode_bits = (x->set_mode ? x->mode : src_mode) & CHMOD_MODE_BITS; omitted_permissions = (dst_mode_bits & (x->preserve_ownership ? S_IRWXG | S_IRWXO : S_ISDIR (src_mode) ? S_IWGRP | S_IWOTH : 0)); delayed_ok = true; if (x->preserve_security_context) { security_context_t con; if (0 <= lgetfilecon (src_name, &con)) { if (setfscreatecon (con) < 0) { error (0, errno, _("failed to set default file creation context to %s"), quote (con)); if (x->require_preserve_context) { freecon (con); return false; } } freecon (con); } else { if (errno != ENOTSUP && errno != ENODATA) { error (0, errno, _("failed to get security context of %s"), quote (src_name)); if (x->require_preserve_context) return false; } } } /* In certain modes (cp's --symbolic-link), and for certain file types (symlinks and hard links) it doesn't make sense to preserve metadata, or it's possible to preserve only some of it. In such cases, set this variable to zero. */ preserve_metadata = true; if (S_ISDIR (src_mode)) { struct dir_list *dir; /* If this directory has been copied before during the recursion, there is a symbolic link to an ancestor directory of the symbolic link. It is impossible to continue to copy this, unless we've got an infinite disk. */ if (is_ancestor (&src_sb, ancestors)) { error (0, 0, _("cannot copy cyclic symbolic link %s"), quote (src_name)); goto un_backup; } /* Insert the current directory in the list of parents. */ dir = alloca (sizeof *dir); dir->parent = ancestors; dir->ino = src_sb.st_ino; dir->dev = src_sb.st_dev; if (new_dst || !S_ISDIR (dst_sb.st_mode)) { /* POSIX says mkdir's behavior is implementation-defined when (src_mode & ~S_IRWXUGO) != 0. However, common practice is to ask mkdir to copy all the CHMOD_MODE_BITS, letting mkdir decide what to do with S_ISUID | S_ISGID | S_ISVTX. */ if (mkdir (dst_name, dst_mode_bits & ~omitted_permissions) != 0) { error (0, errno, _("cannot create directory %s"), quote (dst_name)); goto un_backup; } /* We need search and write permissions to the new directory for writing the directory's contents. Check if these permissions are there. */ if (lstat (dst_name, &dst_sb) != 0) { error (0, errno, _("cannot stat %s"), quote (dst_name)); goto un_backup; } else if ((dst_sb.st_mode & S_IRWXU) != S_IRWXU) { /* Make the new directory searchable and writable. */ dst_mode = dst_sb.st_mode; restore_dst_mode = true; if (lchmod (dst_name, dst_mode | S_IRWXU) != 0) { error (0, errno, _("setting permissions for %s"), quote (dst_name)); goto un_backup; } } /* Insert the created directory's inode and device numbers into the search structure, so that we can avoid copying it again. */ remember_copied (dst_name, dst_sb.st_ino, dst_sb.st_dev); if (x->verbose) emit_verbose (src_name, dst_name, NULL); } /* Decide whether to copy the contents of the directory. */ if (x->one_file_system && device != 0 && device != src_sb.st_dev) { /* Here, we are crossing a file system boundary and cp's -x option is in effect: so don't copy the contents of this directory. */ } else { /* Copy the contents of the directory. Don't just return if this fails -- otherwise, the failure to read a single file in a source directory would cause the containing destination directory not to have owner/perms set properly. */ delayed_ok = copy_dir (src_name, dst_name, new_dst, &src_sb, dir, x, copy_into_self); } } else if (x->symbolic_link) { preserve_metadata = false; if (*src_name != '/') { /* Check that DST_NAME denotes a file in the current directory. */ struct stat dot_sb; struct stat dst_parent_sb; char *dst_parent; bool in_current_dir; dst_parent = dir_name (dst_name); in_current_dir = (STREQ (".", dst_parent) /* If either stat call fails, it's ok not to report the failure and say dst_name is in the current directory. Other things will fail later. */ || stat (".", &dot_sb) != 0 || stat (dst_parent, &dst_parent_sb) != 0 || SAME_INODE (dot_sb, dst_parent_sb)); free (dst_parent); if (! in_current_dir) { error (0, 0, _("%s: can make relative symbolic links only in current directory"), quote (dst_name)); goto un_backup; } } if (symlink (src_name, dst_name) != 0) { error (0, errno, _("cannot create symbolic link %s to %s"), quote_n (0, dst_name), quote_n (1, src_name)); goto un_backup; } } else if (x->hard_link #ifdef LINK_FOLLOWS_SYMLINKS /* A POSIX-conforming link syscall dereferences a symlink, yet cp, invoked with `--link --no-dereference', should not. Thus, with a POSIX-conforming link system call, we can't use link() here, since that would create a hard link to the referent (effectively dereferencing the symlink), rather than to the symlink itself. We can approximate the desired behavior by skipping this hard-link creating block and instead copying the symlink, via the `S_ISLNK'- copying code below. When link operates on the symlinks themselves, we use this block and just call link(). */ && !(S_ISLNK (src_mode) && x->dereference == DEREF_NEVER) #endif ) { preserve_metadata = false; if (link (src_name, dst_name)) { error (0, errno, _("cannot create link %s"), quote (dst_name)); goto un_backup; } } else if (S_ISREG (src_mode) || (x->copy_as_regular && !S_ISLNK (src_mode))) { copied_as_regular = true; /* POSIX says the permission bits of the source file must be used as the 3rd argument in the open call. Historical practice passed all the source mode bits to 'open', but the extra bits were ignored, so it should be the same either way. */ if (! copy_reg (src_name, dst_name, x, src_mode & S_IRWXUGO, omitted_permissions, &new_dst, &src_sb)) goto un_backup; } else if (S_ISFIFO (src_mode)) { /* Use mknod, rather than mkfifo, because the former preserves the special mode bits of a fifo on Solaris 10, while mkfifo does not. But fall back on mkfifo, because on some BSD systems, mknod always fails when asked to create a FIFO. */ if (mknod (dst_name, src_mode & ~omitted_permissions, 0) != 0) #if HAVE_MKFIFO if (mkfifo (dst_name, src_mode & ~S_IFIFO & ~omitted_permissions) != 0) #endif { error (0, errno, _("cannot create fifo %s"), quote (dst_name)); goto un_backup; } } else if (S_ISBLK (src_mode) || S_ISCHR (src_mode) || S_ISSOCK (src_mode)) { if (mknod (dst_name, src_mode & ~omitted_permissions, src_sb.st_rdev) != 0) { error (0, errno, _("cannot create special file %s"), quote (dst_name)); goto un_backup; } } else if (S_ISLNK (src_mode)) { char *src_link_val = mreadlink_with_size (src_name, src_sb.st_size); if (src_link_val == NULL) { error (0, errno, _("cannot read symbolic link %s"), quote (src_name)); goto un_backup; } if (symlink (src_link_val, dst_name) == 0) free (src_link_val); else { int saved_errno = errno; bool same_link = false; if (x->update && !new_dst && S_ISLNK (dst_sb.st_mode) && dst_sb.st_size == strlen (src_link_val)) { /* See if the destination is already the desired symlink. FIXME: This behavior isn't documented, and seems wrong in some cases, e.g., if the destination symlink has the wrong ownership, permissions, or time stamps. */ char *dest_link_val = mreadlink_with_size (dst_name, dst_sb.st_size); if (dest_link_val && STREQ (dest_link_val, src_link_val)) same_link = true; free (dest_link_val); } free (src_link_val); if (! same_link) { error (0, saved_errno, _("cannot create symbolic link %s"), quote (dst_name)); goto un_backup; } } if (x->preserve_security_context) restore_default_fscreatecon_or_die (); /* There's no need to preserve timestamps or permissions. */ preserve_metadata = false; if (x->preserve_ownership) { /* Preserve the owner and group of the just-`copied' symbolic link, if possible. */ if (HAVE_LCHOWN && lchown (dst_name, src_sb.st_uid, src_sb.st_gid) != 0 && ! chown_failure_ok (x)) { error (0, errno, _("failed to preserve ownership for %s"), dst_name); goto un_backup; } else { /* Can't preserve ownership of symlinks. FIXME: maybe give a warning or even error for symlinks in directories with the sticky bit set -- there, not preserving owner/group is a potential security problem. */ } } } else { error (0, 0, _("%s has unknown file type"), quote (src_name)); goto un_backup; } if (command_line_arg) record_file (x->dest_info, dst_name, NULL); if ( ! preserve_metadata) return true; if (copied_as_regular) return delayed_ok; /* POSIX says that `cp -p' must restore the following: - permission bits - setuid, setgid bits - owner and group If it fails to restore any of those, we may give a warning but the destination must not be removed. FIXME: implement the above. */ /* Adjust the times (and if possible, ownership) for the copy. chown turns off set[ug]id bits for non-root, so do the chmod last. */ if (x->preserve_timestamps) { struct timespec timespec[2]; timespec[0] = get_stat_atime (&src_sb); timespec[1] = get_stat_mtime (&src_sb); if (utimens (dst_name, timespec) != 0) { error (0, errno, _("preserving times for %s"), quote (dst_name)); if (x->require_preserve) return false; } } /* Avoid calling chown if we know it's not necessary. */ if (x->preserve_ownership && (new_dst || !SAME_OWNER_AND_GROUP (src_sb, dst_sb))) { switch (set_owner (x, dst_name, -1, src_sb.st_uid, src_sb.st_gid)) { case -1: return false; case 0: src_mode &= ~ (S_ISUID | S_ISGID | S_ISVTX); break; } } set_author (dst_name, -1, &src_sb); if (x->preserve_mode || x->move_mode) { if (copy_acl (src_name, -1, dst_name, -1, src_mode) != 0 && x->require_preserve) return false; } else if (x->set_mode) { if (set_acl (dst_name, -1, x->mode) != 0) return false; } else { if (omitted_permissions) { omitted_permissions &= ~ cached_umask (); if (omitted_permissions && !restore_dst_mode) { /* Permissions were deliberately omitted when the file was created due to security concerns. See whether they need to be re-added now. It'd be faster to omit the lstat, but deducing the current destination mode is tricky in the presence of implementation-defined rules for special mode bits. */ if (new_dst && lstat (dst_name, &dst_sb) != 0) { error (0, errno, _("cannot stat %s"), quote (dst_name)); return false; } dst_mode = dst_sb.st_mode; if (omitted_permissions & ~dst_mode) restore_dst_mode = true; } } if (restore_dst_mode) { if (lchmod (dst_name, dst_mode | omitted_permissions) != 0) { error (0, errno, _("preserving permissions for %s"), quote (dst_name)); if (x->require_preserve) return false; } } } return delayed_ok; un_backup: if (x->preserve_security_context) restore_default_fscreatecon_or_die (); /* We have failed to create the destination file. If we've just added a dev/ino entry via the remember_copied call above (i.e., unless we've just failed to create a hard link), remove the entry associating the source dev/ino with the destination file name, so we don't try to `preserve' a link to a file we didn't create. */ if (earlier_file == NULL) forget_created (src_sb.st_ino, src_sb.st_dev); if (dst_backup) { if (rename (dst_backup, dst_name) != 0) error (0, errno, _("cannot un-backup %s"), quote (dst_name)); else { if (x->verbose) printf (_("%s -> %s (unbackup)\n"), quote_n (0, dst_backup), quote_n (1, dst_name)); } } return false; } static bool valid_options (const struct cp_options *co) { assert (co != NULL); assert (VALID_BACKUP_TYPE (co->backup_type)); assert (VALID_SPARSE_MODE (co->sparse_mode)); assert (!(co->hard_link && co->symbolic_link)); return true; } /* Copy the file SRC_NAME to the file DST_NAME. The files may be of any type. NONEXISTENT_DST should be true if the file DST_NAME is known not to exist (e.g., because its parent directory was just created); NONEXISTENT_DST should be false if DST_NAME might already exist. OPTIONS is ... FIXME-describe Set *COPY_INTO_SELF if SRC_NAME is a parent of (or the same as) DST_NAME; otherwise, set clear it. Return true if successful. */ extern bool copy (char const *src_name, char const *dst_name, bool nonexistent_dst, const struct cp_options *options, bool *copy_into_self, bool *rename_succeeded) { assert (valid_options (options)); /* Record the file names: they're used in case of error, when copying a directory into itself. I don't like to make these tools do *any* extra work in the common case when that work is solely to handle exceptional cases, but in this case, I don't see a way to derive the top level source and destination directory names where they're used. An alternative is to use COPY_INTO_SELF and print the diagnostic from every caller -- but I don't want to do that. */ top_level_src_name = src_name; top_level_dst_name = dst_name; return copy_internal (src_name, dst_name, nonexistent_dst, 0, NULL, options, true, copy_into_self, rename_succeeded); } /* Return true if this process has appropriate privileges to chown a file whose owner is not the effective user ID. */ extern bool chown_privileges (void) { #ifdef PRIV_FILE_CHOWN bool result; priv_set_t *pset = priv_allocset (); if (!pset) xalloc_die (); result = (getppriv (PRIV_EFFECTIVE, pset) == 0 && priv_ismember (pset, PRIV_FILE_CHOWN)); priv_freeset (pset); return result; #else return (geteuid () == 0); #endif } /* Return true if it's OK for chown to fail, where errno is the error number that chown failed with and X is the copying option set. */ extern bool chown_failure_ok (struct cp_options const *x) { /* If non-root uses -p, it's ok if we can't preserve ownership. But root probably wants to know, e.g. if NFS disallows it, or if the target system doesn't support file ownership. */ return ((errno == EPERM || errno == EINVAL) && !x->chown_privileges); } /* Return the user's umask, caching the result. */ extern mode_t cached_umask (void) { static mode_t mask = (mode_t) -1; if (mask == (mode_t) -1) { mask = umask (0); umask (mask); } return mask; }