archival/libarchive/data_extract_all.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   4  */
   5
   6 #include "libbb.h"
   7 #include "bb_archive.h"
   8
   9 void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
  10 {
  11
  12         file_header_t *file_header = archive_handle->file_header;
  13         int dst_fd;
  14         int res;
  15         char *hard_link;
  16 #if ENABLE_FEATURE_TAR_LONG_OPTIONS
  17         char *dst_name;
  18 #else
  19 # define dst_name (file_header->name)
  20 #endif
  21
  22 #if ENABLE_FEATURE_TAR_SELINUX
  23         char *sctx = archive_handle->tar__sctx[PAX_NEXT_FILE];
  24         if (!sctx)
  25                 sctx = archive_handle->tar__sctx[PAX_GLOBAL];
  26         if (sctx) { /* setfscreatecon is 4 syscalls, avoid if possible */
  27                 setfscreatecon(sctx);
  28                 free(archive_handle->tar__sctx[PAX_NEXT_FILE]);
  29                 archive_handle->tar__sctx[PAX_NEXT_FILE] = NULL;
  30         }
  31 #endif
  32
  33         /* Hard links are encoded as regular files of size 0
  34          * with a nonempty link field */
  35         hard_link = NULL;
  36         if (S_ISREG(file_header->mode) && file_header->size == 0)
  37                 hard_link = file_header->link_target;
  38
  39 #if ENABLE_FEATURE_TAR_LONG_OPTIONS
  40         dst_name = file_header->name;
  41         if (archive_handle->tar__strip_components) {
  42                 unsigned n = archive_handle->tar__strip_components;
  43                 do {
  44                         dst_name = strchr(dst_name, '/');
  45                         if (!dst_name || dst_name[1] == '\0') {
  46                                 data_skip(archive_handle);
  47                                 return;
  48                         }
  49                         dst_name++;
  50                         /*
  51                          * Link target is shortened only for hardlinks:
  52                          * softlinks restored unchanged.
  53                          */
  54                         if (hard_link) {
  55 // GNU tar 1.26 does not check that we reached end of link name:
  56 // if "dir/hardlink" is hardlinked to "file",
  57 // tar xvf a.tar --strip-components=1 says:
  58 //  tar: hardlink: Cannot hard link to '': No such file or directory
  59 // and continues processing. We silently skip such entries.
  60                                 hard_link = strchr(hard_link, '/');
  61                                 if (!hard_link || hard_link[1] == '\0') {
  62                                         data_skip(archive_handle);
  63                                         return;
  64                                 }
  65                                 hard_link++;
  66                         }
  67                 } while (--n != 0);
  68         }
  69 #endif
  70
  71         if (archive_handle->ah_flags & ARCHIVE_CREATE_LEADING_DIRS) {
  72                 char *slash = strrchr(dst_name, '/');
  73                 if (slash) {
  74                         *slash = '\0';
  75                         bb_make_directory(dst_name, -1, FILEUTILS_RECUR);
  76                         *slash = '/';
  77                 }
  78         }
  79
  80         if (archive_handle->ah_flags & ARCHIVE_UNLINK_OLD) {
  81                 /* Remove the entry if it exists */
  82                 if (!S_ISDIR(file_header->mode)) {
  83                         if (hard_link) {
  84                                 /* Ugly special case:
  85                                  * tar cf t.tar hardlink1 hardlink2 hardlink1
  86                                  * results in this tarball structure:
  87                                  * hardlink1
  88                                  * hardlink2 -> hardlink1
  89                                  * hardlink1 -> hardlink1 <== !!!
  90                                  */
  91                                 if (strcmp(hard_link, dst_name) == 0)
  92                                         goto ret;
  93                         }
  94                         /* Proceed with deleting */
  95                         if (unlink(dst_name) == -1
  96                          && errno != ENOENT
  97                         ) {
  98                                 bb_perror_msg_and_die("can't remove old file %s",
  99                                                 dst_name);
 100                         }
 101                 }
 102         }
 103         else if (archive_handle->ah_flags & ARCHIVE_EXTRACT_NEWER) {
 104                 /* Remove the existing entry if its older than the extracted entry */
 105                 struct stat existing_sb;
 106                 if (lstat(dst_name, &existing_sb) == -1) {
 107                         if (errno != ENOENT) {
 108                                 bb_perror_msg_and_die("can't stat old file");
 109                         }
 110                 }
 111                 else if (existing_sb.st_mtime >= file_header->mtime) {
 112                         if (!(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
 113                          && !S_ISDIR(file_header->mode)
 114                         ) {
 115                                 bb_error_msg("%s not created: newer or "
 116                                         "same age file exists", dst_name);
 117                         }
 118                         data_skip(archive_handle);
 119                         goto ret;
 120                 }
 121                 else if ((unlink(dst_name) == -1) && (errno != EISDIR)) {
 122                         bb_perror_msg_and_die("can't remove old file %s",
 123                                         dst_name);
 124                 }
 125         }
 126
 127         /* Handle hard links separately */
 128         if (hard_link) {
 129                 res = link(hard_link, dst_name);
 130                 if (res != 0 && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)) {
 131                         bb_perror_msg("can't create %slink "
 132                                         "from %s to %s", "hard",
 133                                         dst_name,
 134                                         hard_link);
 135                 }
 136                 /* Hardlinks have no separate mode/ownership, skip chown/chmod */
 137                 goto ret;
 138         }
 139
 140         /* Create the filesystem entry */
 141         switch (file_header->mode & S_IFMT) {
 142         case S_IFREG: {
 143                 /* Regular file */
 144                 char *dst_nameN;
 145                 int flags = O_WRONLY | O_CREAT | O_EXCL;
 146                 if (archive_handle->ah_flags & ARCHIVE_O_TRUNC)
 147                         flags = O_WRONLY | O_CREAT | O_TRUNC;
 148                 dst_nameN = dst_name;
 149 #ifdef ARCHIVE_REPLACE_VIA_RENAME
 150                 if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME)
 151                         /* rpm-style temp file name */
 152                         dst_nameN = xasprintf("%s;%x", dst_name, (int)getpid());
 153 #endif
 154                 dst_fd = xopen3(dst_nameN,
 155                         flags,
 156                         file_header->mode
 157                         );
 158                 bb_copyfd_exact_size(archive_handle->src_fd, dst_fd, file_header->size);
 159                 close(dst_fd);
 160 #ifdef ARCHIVE_REPLACE_VIA_RENAME
 161                 if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME) {
 162                         xrename(dst_nameN, dst_name);
 163                         free(dst_nameN);
 164                 }
 165 #endif
 166                 break;
 167         }
 168         case S_IFDIR:
 169                 res = mkdir(dst_name, file_header->mode);
 170                 if ((res == -1)
 171                  && (errno != EISDIR) /* btw, Linux doesn't return this */
 172                  && (errno != EEXIST)
 173                  && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
 174                 ) {
 175                         bb_perror_msg("can't make dir %s", dst_name);
 176                 }
 177                 break;
 178         case S_IFLNK:
 179                 /* Symlink */
 180 //TODO: what if file_header->link_target == NULL (say, corrupted tarball?)
 181                 res = symlink(file_header->link_target, dst_name);
 182                 if (res != 0
 183                  && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
 184                 ) {
 185                         bb_perror_msg("can't create %slink "
 186                                 "from %s to %s", "sym",
 187                                 dst_name,
 188                                 file_header->link_target);
 189                 }
 190                 break;
 191         case S_IFSOCK:
 192         case S_IFBLK:
 193         case S_IFCHR:
 194         case S_IFIFO:
 195                 res = mknod(dst_name, file_header->mode, file_header->device);
 196                 if ((res == -1)
 197                  && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
 198                 ) {
 199                         bb_perror_msg("can't create node %s", dst_name);
 200                 }
 201                 break;
 202         default:
 203                 bb_error_msg_and_die("unrecognized file type");
 204         }
 205
 206         if (!S_ISLNK(file_header->mode)) {
 207                 if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_OWNER)) {
 208                         uid_t uid = file_header->uid;
 209                         gid_t gid = file_header->gid;
 210 #if ENABLE_FEATURE_TAR_UNAME_GNAME
 211                         if (!(archive_handle->ah_flags & ARCHIVE_NUMERIC_OWNER)) {
 212                                 if (file_header->tar__uname) {
 213 //TODO: cache last name/id pair?
 214                                         struct passwd *pwd = getpwnam(file_header->tar__uname);
 215                                         if (pwd) uid = pwd->pw_uid;
 216                                 }
 217                                 if (file_header->tar__gname) {
 218                                         struct group *grp = getgrnam(file_header->tar__gname);
 219                                         if (grp) gid = grp->gr_gid;
 220                                 }
 221                         }
 222 #endif
 223                         /* GNU tar 1.15.1 uses chown, not lchown */
 224                         chown(dst_name, uid, gid);
 225                 }
 226                 /* uclibc has no lchmod, glibc is even stranger -
 227                  * it has lchmod which seems to do nothing!
 228                  * so we use chmod... */
 229                 if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_PERM)) {
 230                         chmod(dst_name, file_header->mode);
 231                 }
 232                 if (archive_handle->ah_flags & ARCHIVE_RESTORE_DATE) {
 233                         struct timeval t[2];
 234
 235                         t[1].tv_sec = t[0].tv_sec = file_header->mtime;
 236                         t[1].tv_usec = t[0].tv_usec = 0;
 237                         utimes(dst_name, t);
 238                 }
 239         }
 240
 241  ret: ;
 242 #if ENABLE_FEATURE_TAR_SELINUX
 243         if (sctx) {
 244                 /* reset the context after creating an entry */
 245                 setfscreatecon(NULL);
 246         }
 247 #endif
 248 }