passwd: rework:
[oweals/busybox.git] / libbb / copy_file.c
index eb9cb1a16b6bec90458465340ead4b39a80d97dd..0135831fe0a35536ddfc090f74e18f36dd0c9cf1 100644 (file)
 /* vi: set sw=4 ts=4: */
 /*
- * Utility routines.
+ * Mini copy_file implementation for busybox
  *
- * Copyright (C) tons of folks.  Tracking down who wrote what
- * isn't something I'm going to worry about...  If you wrote something
- * here, please feel free to acknowledge your work.
+ * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- * Based in part on code from sash, Copyright (c) 1999 by David I. Bell 
- * Permission has been granted to redistribute this code under the GPL.
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  *
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <utime.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/stat.h>
 #include "libbb.h"
 
+static int retry_overwrite(const char *dest, int flags)
+{
+       if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
+               fprintf(stderr, "'%s' exists\n", dest);
+               return -1;
+       }
+       if (flags & FILEUTILS_INTERACTIVE) {
+               fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
+               if (!bb_ask_confirmation())
+                       return 0; // not allowed to overwrite
+       }
+       if (unlink(dest) < 0) {
+               bb_perror_msg("cannot remove '%s'", dest);
+               return -1; // error
+       }
+       return 1; // ok (to try again)
+}
 
-/*
- * Copy one file to another, while possibly preserving its modes, times, and
- * modes.  Returns TRUE if successful, or FALSE on a failure with an error
- * message output.  (Failure is not indicated if attributes cannot be set.)
- * -Erik Andersen
- */
-int
-copy_file(const char *src_name, const char *dst_name,
-                int set_modes, int follow_links, int force_flag, int quiet_flag)
+int copy_file(const char *source, const char *dest, int flags)
 {
-       FILE *src_file = NULL;
-       FILE *dst_file = NULL;
-       struct stat srcStatBuf;
-       struct stat dstStatBuf;
-       struct utimbuf times;
-       int src_status;
-       int dst_status;
-
-       if (follow_links == TRUE) {
-               src_status = stat(src_name, &srcStatBuf);
-               dst_status = stat(dst_name, &dstStatBuf);
-       } else {
-               src_status = lstat(src_name, &srcStatBuf);
-               dst_status = lstat(dst_name, &dstStatBuf);
+       struct stat source_stat;
+       struct stat dest_stat;
+       int status = 0;
+       signed char dest_exists = 0;
+       signed char ovr;
+
+#define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
+
+       if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
+               // This may be a dangling symlink.
+               // Making [sym]links to dangling symlinks works, so...
+               if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
+                       goto make_links;
+               bb_perror_msg("cannot stat '%s'", source);
+               return -1;
        }
 
-       if (src_status < 0) {
-               if (!quiet_flag) {
-                       perror_msg("%s", src_name);
+       if (lstat(dest, &dest_stat) < 0) {
+               if (errno != ENOENT) {
+                       bb_perror_msg("cannot stat '%s'", dest);
+                       return -1;
                }
-               return FALSE;
+       } else {
+               if (source_stat.st_dev == dest_stat.st_dev
+                && source_stat.st_ino == dest_stat.st_ino
+               ) {
+                       bb_error_msg("'%s' and '%s' are the same file", source, dest);
+                       return -1;
+               }
+               dest_exists = 1;
        }
 
-       if ((dst_status < 0) || force_flag) {
-               unlink(dst_name);
-               dstStatBuf.st_ino = -1;
-               dstStatBuf.st_dev = -1;
-       }
+       if (S_ISDIR(source_stat.st_mode)) {
+               DIR *dp;
+               struct dirent *d;
+               mode_t saved_umask = 0;
 
-       if ((srcStatBuf.st_dev == dstStatBuf.st_dev) &&
-               (srcStatBuf.st_ino == dstStatBuf.st_ino)) {
-               if (!quiet_flag) {
-                       error_msg("Copying file \"%s\" to itself", src_name);
+               if (!(flags & FILEUTILS_RECUR)) {
+                       bb_error_msg("omitting directory '%s'", source);
+                       return -1;
                }
-               return FALSE;
-       }
 
-       if (S_ISDIR(srcStatBuf.st_mode)) {
-               //fprintf(stderr, "copying directory %s to %s\n", srcName, destName);
-               /* Make sure the directory is writable */
-               dst_status = create_path(dst_name, 0777777 ^ umask(0));
-               if ((dst_status < 0) && (errno != EEXIST)) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", dst_name);
+               /* Create DEST.  */
+               if (dest_exists) {
+                       if (!S_ISDIR(dest_stat.st_mode)) {
+                               bb_error_msg("target '%s' is not a directory", dest);
+                               return -1;
                        }
-                       return FALSE;
-               }
-       } else if (S_ISLNK(srcStatBuf.st_mode)) {
-               char link_val[BUFSIZ + 1];
-               int link_size;
-
-               //fprintf(stderr, "copying link %s to %s\n", srcName, destName);
-               /* Warning: This could possibly truncate silently, to BUFSIZ chars */
-               link_size = readlink(src_name, &link_val[0], BUFSIZ);
-               if (link_size < 0) {
-                       if (quiet_flag) {
-                               perror_msg("%s", src_name);
+               } else {
+                       mode_t mode;
+                       saved_umask = umask(0);
+
+                       mode = source_stat.st_mode;
+                       if (!(flags & FILEUTILS_PRESERVE_STATUS))
+                               mode = source_stat.st_mode & ~saved_umask;
+                       mode |= S_IRWXU;
+
+                       if (mkdir(dest, mode) < 0) {
+                               umask(saved_umask);
+                               bb_perror_msg("cannot create directory '%s'", dest);
+                               return -1;
                        }
-                       return FALSE;
+
+                       umask(saved_umask);
+               }
+
+               /* Recursively copy files in SOURCE.  */
+               dp = opendir(source);
+               if (dp == NULL) {
+                       status = -1;
+                       goto preserve_status;
+               }
+
+               while ((d = readdir(dp)) != NULL) {
+                       char *new_source, *new_dest;
+
+                       new_source = concat_subpath_file(source, d->d_name);
+                       if (new_source == NULL)
+                               continue;
+                       new_dest = concat_path_file(dest, d->d_name);
+                       if (copy_file(new_source, new_dest, flags) < 0)
+                               status = -1;
+                       free(new_source);
+                       free(new_dest);
                }
-               link_val[link_size] = '\0';
-               src_status = symlink(link_val, dst_name);
-               if (src_status < 0) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", dst_name);
+               closedir(dp);
+
+               if (!dest_exists
+                && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
+               ) {
+                       bb_perror_msg("cannot change permissions of '%s'", dest);
+                       status = -1;
+               }
+
+       } else if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
+               int (*lf)(const char *oldpath, const char *newpath);
+ make_links:
+               // Hmm... maybe
+               // if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
+               // (but realpath returns NULL on dangling symlinks...)
+               lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
+               if (lf(source, dest) < 0) {
+                       ovr = retry_overwrite(dest, flags);
+                       if (ovr <= 0)
+                               return ovr;
+                       if (lf(source, dest) < 0) {
+                               bb_perror_msg("cannot create link '%s'", dest);
+                               return -1;
                        }
-                       return FALSE;
-               }
-#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
-               if (set_modes == TRUE) {
-                       /* Try to set owner, but fail silently like GNU cp */
-                       lchown(dst_name, srcStatBuf.st_uid, srcStatBuf.st_gid);
-               }
-#endif
-               return TRUE;
-       } else if (S_ISFIFO(srcStatBuf.st_mode)) {
-               //fprintf(stderr, "copying fifo %s to %s\n", srcName, destName);
-               if (mkfifo(dst_name, 0644) < 0) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", dst_name);
+               }
+               return 0;
+
+       } else if (S_ISREG(source_stat.st_mode)
+       // Huh? DEREF uses stat, which never returns links IIRC...
+        || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) 
+       ) {
+               int src_fd;
+               int dst_fd;
+               if (ENABLE_FEATURE_PRESERVE_HARDLINKS) {
+                       char *link_name;
+
+                       if (!FLAGS_DEREF
+                        && is_in_ino_dev_hashtable(&source_stat, &link_name)
+                       ) {
+                               if (link(link_name, dest) < 0) {
+                                       ovr = retry_overwrite(dest, flags);
+                                       if (ovr <= 0)
+                                               return ovr;
+                                       if (link(link_name, dest) < 0) {
+                                               bb_perror_msg("cannot create link '%s'", dest);
+                                               return -1;
+                                       }
+                               }
+                               return 0;
                        }
-                       return FALSE;
-               }
-       } else if (S_ISBLK(srcStatBuf.st_mode) || S_ISCHR(srcStatBuf.st_mode)
-                          || S_ISSOCK(srcStatBuf.st_mode)) {
-               //fprintf(stderr, "copying soc, blk, or chr %s to %s\n", srcName, destName);
-               if (mknod(dst_name, srcStatBuf.st_mode, srcStatBuf.st_rdev) < 0) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", dst_name);
+                       // TODO: probably is_in_.. and add_to_...
+                       // can be combined: find_or_add_...
+                       add_to_ino_dev_hashtable(&source_stat, dest);
+               }
+
+               src_fd = open(source, O_RDONLY);
+               if (src_fd == -1) {
+                       bb_perror_msg("cannot open '%s'", source);
+                       return -1;
+               }
+
+               // POSIX: if exists and -i, ask (w/o -i assume yes).
+               // Then open w/o EXCL.
+               // If open still fails and -f, try unlink, then try open again.
+               // Result: a mess:
+               // If dest is a softlink, we overwrite softlink's destination!
+               // (or fail, if it points to dir/nonexistent location/etc).
+               // This is strange, but POSIX-correct.
+               // coreutils cp has --remove-destination to override this...
+               dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE)
+                               ? O_WRONLY|O_CREAT|O_TRUNC|O_EXCL
+                               : O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
+               if (dst_fd == -1) {
+                       // We would not do POSIX insanity. -i asks,
+                       // then _unlinks_ the offender. Presto.
+                       // Or else we will end up having 3 open()s!
+                       ovr = retry_overwrite(dest, flags);
+                       if (ovr <= 0) {
+                               close(src_fd);
+                               return ovr;
                        }
-                       return FALSE;
-               }
-       } else if (S_ISREG(srcStatBuf.st_mode)) {
-               //fprintf(stderr, "copying regular file %s to %s\n", srcName, destName);
-               src_file = fopen(src_name, "r");
-               if (src_file == NULL) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", src_name);
+                       dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
+                       if (dst_fd == -1) {
+                               bb_perror_msg("cannot open '%s'", dest);
+                               close(src_fd);
+                               return -1;
                        }
-                       return FALSE;
                }
 
-               dst_file = fopen(dst_name, "w");
-               if (dst_file == NULL) {
-                       if (!quiet_flag) {
-                               perror_msg("%s", dst_name);
-                       }
-                       fclose(src_file);
-                       return FALSE;
+               if (bb_copyfd_eof(src_fd, dst_fd) == -1)
+                       status = -1;
+               if (close(dst_fd) < 0) {
+                       bb_perror_msg("cannot close '%s'", dest);
+                       status = -1;
+               }
+               if (close(src_fd) < 0) {
+                       bb_perror_msg("cannot close '%s'", source);
+                       status = -1;
                }
 
-               if (copy_file_chunk(src_file, dst_file, srcStatBuf.st_size)==FALSE) {
-                       goto error_exit;
+       } else if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
+        || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
+        || S_ISLNK(source_stat.st_mode)
+       ) {
+               // We are lazy here, a bit lax with races...
+               if (dest_exists) {
+                       ovr = retry_overwrite(dest, flags);
+                       if (ovr <= 0)
+                               return ovr;
                }
+               if (S_ISFIFO(source_stat.st_mode)) {
+                       if (mkfifo(dest, source_stat.st_mode) < 0) {
+                               bb_perror_msg("cannot create fifo '%s'", dest);
+                               return -1;
+                       }
+               } else if (S_ISLNK(source_stat.st_mode)) {
+                       char *lpath;
+
+                       lpath = xreadlink(source);
+                       if (symlink(lpath, dest) < 0) {
+                               bb_perror_msg("cannot create symlink '%s'", dest);
+                               free(lpath);
+                               return -1;
+                       }
+                       free(lpath);
 
-               fclose(src_file);
-               if (fclose(dst_file) < 0) {
-                       return FALSE;
+                       if (flags & FILEUTILS_PRESERVE_STATUS)
+                               if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
+                                       bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
+
+                       return 0;
+
+               } else {
+                       if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
+                               bb_perror_msg("cannot create '%s'", dest);
+                               return -1;
+                       }
                }
+       } else {
+               bb_error_msg("internal error: unrecognized file type");
+               return -1;
        }
 
-       if (set_modes == TRUE) {
-               /* This is fine, since symlinks never get here */
-               if (chown(dst_name, srcStatBuf.st_uid, srcStatBuf.st_gid) < 0)
-                       perror_msg("%s", dst_name);
-               if (chmod(dst_name, srcStatBuf.st_mode) < 0)
-                       perror_msg("%s", dst_name);
-               times.actime = srcStatBuf.st_atime;
-               times.modtime = srcStatBuf.st_mtime;
-               if (utime(dst_name, &times) < 0)
-                       perror_msg("%s", dst_name);
-       }
+ preserve_status:
 
-       return TRUE;
+       if (flags & FILEUTILS_PRESERVE_STATUS
+       /* Cannot happen: */
+       /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
+       ) {
+               struct utimbuf times;
 
-error_exit:
-       perror_msg("%s", dst_name);
-       fclose(src_file);
-       fclose(dst_file);
+               times.actime = source_stat.st_atime;
+               times.modtime = source_stat.st_mtime;
+               if (utime(dest, &times) < 0)
+                       bb_perror_msg("cannot preserve %s of '%s'", "times", dest);
+               if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
+                       source_stat.st_mode &= ~(S_ISUID | S_ISGID);
+                       bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
+               }
+               if (chmod(dest, source_stat.st_mode) < 0)
+                       bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
+       }
 
-       return FALSE;
+       return status;
 }
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/