libbb/copy_file.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini copy_file implementation for busybox
   4  *
   5  * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
   6  * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  *
  10  */
  11
  12 #include "libbb.h"
  13
  14 static int retry_overwrite(const char *dest, int flags)
  15 {
  16         if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
  17                 fprintf(stderr, "'%s' exists\n", dest);
  18                 return -1;
  19         }
  20         if (flags & FILEUTILS_INTERACTIVE) {
  21                 fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
  22                 if (!bb_ask_confirmation())
  23                         return 0; // not allowed to overwrite
  24         }
  25         if (unlink(dest) < 0) {
  26                 bb_perror_msg("cannot remove '%s'", dest);
  27                 return -1; // error
  28         }
  29         return 1; // ok (to try again)
  30 }
  31
  32 int copy_file(const char *source, const char *dest, int flags)
  33 {
  34         struct stat source_stat;
  35         struct stat dest_stat;
  36         int status = 0;
  37         signed char dest_exists = 0;
  38         signed char ovr;
  39
  40 #define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
  41
  42         if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
  43                 // This may be a dangling symlink.
  44                 // Making [sym]links to dangling symlinks works, so...
  45                 if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
  46                         goto make_links;
  47                 bb_perror_msg("cannot stat '%s'", source);
  48                 return -1;
  49         }
  50
  51         if (lstat(dest, &dest_stat) < 0) {
  52                 if (errno != ENOENT) {
  53                         bb_perror_msg("cannot stat '%s'", dest);
  54                         return -1;
  55                 }
  56         } else {
  57                 if (source_stat.st_dev == dest_stat.st_dev
  58                  && source_stat.st_ino == dest_stat.st_ino
  59                 ) {
  60                         bb_error_msg("'%s' and '%s' are the same file", source, dest);
  61                         return -1;
  62                 }
  63                 dest_exists = 1;
  64         }
  65
  66 #if ENABLE_SELINUX
  67         if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) {
  68                 security_context_t con;
  69                 if (lgetfilecon(source, &con) >= 0) {
  70                         if (setfscreatecon(con) < 0) {
  71                                 bb_perror_msg("cannot set setfscreatecon %s", con);
  72                                 freecon(con);
  73                                 return -1;
  74                         }
  75                 } else {
  76                         if (errno == ENOTSUP || errno == ENODATA) {
  77                                 setfscreatecon(NULL);
  78                         } else {
  79                                 bb_perror_msg("cannot lgetfilecon %s", source);
  80                                 return -1;
  81                         }
  82                 }
  83         }
  84 #endif
  85
  86         if (S_ISDIR(source_stat.st_mode)) {
  87                 DIR *dp;
  88                 struct dirent *d;
  89                 mode_t saved_umask = 0;
  90
  91                 if (!(flags & FILEUTILS_RECUR)) {
  92                         bb_error_msg("omitting directory '%s'", source);
  93                         return -1;
  94                 }
  95
  96                 /* Create DEST.  */
  97                 if (dest_exists) {
  98                         if (!S_ISDIR(dest_stat.st_mode)) {
  99                                 bb_error_msg("target '%s' is not a directory", dest);
 100                                 return -1;
 101                         }
 102                 } else {
 103                         mode_t mode;
 104                         saved_umask = umask(0);
 105
 106                         mode = source_stat.st_mode;
 107                         if (!(flags & FILEUTILS_PRESERVE_STATUS))
 108                                 mode = source_stat.st_mode & ~saved_umask;
 109                         mode |= S_IRWXU;
 110
 111                         if (mkdir(dest, mode) < 0) {
 112                                 umask(saved_umask);
 113                                 bb_perror_msg("cannot create directory '%s'", dest);
 114                                 return -1;
 115                         }
 116
 117                         umask(saved_umask);
 118                 }
 119
 120                 /* Recursively copy files in SOURCE.  */
 121                 dp = opendir(source);
 122                 if (dp == NULL) {
 123                         status = -1;
 124                         goto preserve_status;
 125                 }
 126
 127                 while ((d = readdir(dp)) != NULL) {
 128                         char *new_source, *new_dest;
 129
 130                         new_source = concat_subpath_file(source, d->d_name);
 131                         if (new_source == NULL)
 132                                 continue;
 133                         new_dest = concat_path_file(dest, d->d_name);
 134                         if (copy_file(new_source, new_dest, flags) < 0)
 135                                 status = -1;
 136                         free(new_source);
 137                         free(new_dest);
 138                 }
 139                 closedir(dp);
 140
 141                 if (!dest_exists
 142                  && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
 143                 ) {
 144                         bb_perror_msg("cannot change permissions of '%s'", dest);
 145                         status = -1;
 146                 }
 147
 148         } else if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
 149                 int (*lf)(const char *oldpath, const char *newpath);
 150  make_links:
 151                 // Hmm... maybe
 152                 // if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
 153                 // (but realpath returns NULL on dangling symlinks...)
 154                 lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
 155                 if (lf(source, dest) < 0) {
 156                         ovr = retry_overwrite(dest, flags);
 157                         if (ovr <= 0)
 158                                 return ovr;
 159                         if (lf(source, dest) < 0) {
 160                                 bb_perror_msg("cannot create link '%s'", dest);
 161                                 return -1;
 162                         }
 163                 }
 164                 return 0;
 165
 166         } else if (S_ISREG(source_stat.st_mode)
 167         // Huh? DEREF uses stat, which never returns links IIRC...
 168          || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode))
 169         ) {
 170                 int src_fd;
 171                 int dst_fd;
 172                 if (ENABLE_FEATURE_PRESERVE_HARDLINKS) {
 173                         char *link_name;
 174
 175                         if (!FLAGS_DEREF
 176                          && is_in_ino_dev_hashtable(&source_stat, &link_name)
 177                         ) {
 178                                 if (link(link_name, dest) < 0) {
 179                                         ovr = retry_overwrite(dest, flags);
 180                                         if (ovr <= 0)
 181                                                 return ovr;
 182                                         if (link(link_name, dest) < 0) {
 183                                                 bb_perror_msg("cannot create link '%s'", dest);
 184                                                 return -1;
 185                                         }
 186                                 }
 187                                 return 0;
 188                         }
 189                         // TODO: probably is_in_.. and add_to_...
 190                         // can be combined: find_or_add_...
 191                         add_to_ino_dev_hashtable(&source_stat, dest);
 192                 }
 193
 194                 src_fd = open(source, O_RDONLY);
 195                 if (src_fd == -1) {
 196                         bb_perror_msg("cannot open '%s'", source);
 197                         return -1;
 198                 }
 199
 200                 // POSIX: if exists and -i, ask (w/o -i assume yes).
 201                 // Then open w/o EXCL.
 202                 // If open still fails and -f, try unlink, then try open again.
 203                 // Result: a mess:
 204                 // If dest is a softlink, we overwrite softlink's destination!
 205                 // (or fail, if it points to dir/nonexistent location/etc).
 206                 // This is strange, but POSIX-correct.
 207                 // coreutils cp has --remove-destination to override this...
 208                 dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE)
 209                                 ? O_WRONLY|O_CREAT|O_TRUNC|O_EXCL
 210                                 : O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
 211                 if (dst_fd == -1) {
 212                         // We would not do POSIX insanity. -i asks,
 213                         // then _unlinks_ the offender. Presto.
 214                         // Or else we will end up having 3 open()s!
 215                         ovr = retry_overwrite(dest, flags);
 216                         if (ovr <= 0) {
 217                                 close(src_fd);
 218                                 return ovr;
 219                         }
 220                         dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
 221                         if (dst_fd == -1) {
 222                                 bb_perror_msg("cannot open '%s'", dest);
 223                                 close(src_fd);
 224                                 return -1;
 225                         }
 226                 }
 227
 228 #if ENABLE_SELINUX
 229                 if (((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT)
 230                     || (flags & FILEUTILS_SET_SECURITY_CONTEXT))
 231                  && is_selinux_enabled() > 0) {
 232                         security_context_t con;
 233                         if (getfscreatecon(&con) == -1) {
 234                                 bb_perror_msg("getfscreatecon");
 235                                 return -1;
 236                         }
 237                         if (con) {
 238                                 if(setfilecon(dest, con) == -1) {
 239                                         bb_perror_msg("setfilecon:%s,%s", dest, con);
 240                                         freecon(con);
 241                                         return -1;
 242                                 }
 243                                 freecon(con);
 244                         }
 245                 }
 246 #endif
 247                 if (bb_copyfd_eof(src_fd, dst_fd) == -1)
 248                         status = -1;
 249                 if (close(dst_fd) < 0) {
 250                         bb_perror_msg("cannot close '%s'", dest);
 251                         status = -1;
 252                 }
 253                 if (close(src_fd) < 0) {
 254                         bb_perror_msg("cannot close '%s'", source);
 255                         status = -1;
 256                 }
 257
 258         } else if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
 259          || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
 260          || S_ISLNK(source_stat.st_mode)
 261         ) {
 262                 // We are lazy here, a bit lax with races...
 263                 if (dest_exists) {
 264                         ovr = retry_overwrite(dest, flags);
 265                         if (ovr <= 0)
 266                                 return ovr;
 267                 }
 268                 if (S_ISFIFO(source_stat.st_mode)) {
 269                         if (mkfifo(dest, source_stat.st_mode) < 0) {
 270                                 bb_perror_msg("cannot create fifo '%s'", dest);
 271                                 return -1;
 272                         }
 273                 } else if (S_ISLNK(source_stat.st_mode)) {
 274                         char *lpath;
 275
 276                         lpath = xmalloc_readlink_or_warn(source);
 277                         if (symlink(lpath, dest) < 0) {
 278                                 bb_perror_msg("cannot create symlink '%s'", dest);
 279                                 free(lpath);
 280                                 return -1;
 281                         }
 282                         free(lpath);
 283
 284                         if (flags & FILEUTILS_PRESERVE_STATUS)
 285                                 if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
 286                                         bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
 287
 288                         return 0;
 289
 290                 } else {
 291                         if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
 292                                 bb_perror_msg("cannot create '%s'", dest);
 293                                 return -1;
 294                         }
 295                 }
 296         } else {
 297                 bb_error_msg("internal error: unrecognized file type");
 298                 return -1;
 299         }
 300
 301  preserve_status:
 302
 303         if (flags & FILEUTILS_PRESERVE_STATUS
 304         /* Cannot happen: */
 305         /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
 306         ) {
 307                 struct utimbuf times;
 308
 309                 times.actime = source_stat.st_atime;
 310                 times.modtime = source_stat.st_mtime;
 311                 if (utime(dest, &times) < 0)
 312                         bb_perror_msg("cannot preserve %s of '%s'", "times", dest);
 313                 if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
 314                         source_stat.st_mode &= ~(S_ISUID | S_ISGID);
 315                         bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
 316                 }
 317                 if (chmod(dest, source_stat.st_mode) < 0)
 318                         bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
 319         }
 320
 321         return status;
 322 }