archival/libarchive/open_transformer.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 init_transformer_aux_data(transformer_aux_data_t *aux)
  10 {
  11         memset(aux, 0, sizeof(*aux));
  12 }
  13
  14 int FAST_FUNC check_signature16(transformer_aux_data_t *aux, int src_fd, unsigned magic16)
  15 {
  16         if (aux && aux->check_signature) {
  17                 uint16_t magic2;
  18                 if (full_read(src_fd, &magic2, 2) != 2 || magic2 != magic16) {
  19                         bb_error_msg("invalid magic");
  20 #if 0 /* possible future extension */
  21                         if (aux->check_signature > 1)
  22                                 xfunc_die();
  23 #endif
  24                         return -1;
  25                 }
  26         }
  27         return 0;
  28 }
  29
  30 void check_errors_in_children(int signo)
  31 {
  32         int status;
  33
  34         if (!signo) {
  35                 /* block waiting for any child */
  36                 if (wait(&status) < 0)
  37 //FIXME: check EINTR?
  38                         return; /* probably there are no children */
  39                 goto check_status;
  40         }
  41
  42         /* Wait for any child without blocking */
  43         for (;;) {
  44                 if (wait_any_nohang(&status) < 0)
  45 //FIXME: check EINTR?
  46                         /* wait failed?! I'm confused... */
  47                         return;
  48  check_status:
  49                 /*if (WIFEXITED(status) && WEXITSTATUS(status) == 0)*/
  50                 /* On Linux, the above can be checked simply as: */
  51                 if (status == 0)
  52                         /* this child exited with 0 */
  53                         continue;
  54                 /* Cannot happen:
  55                 if (!WIFSIGNALED(status) && !WIFEXITED(status)) ???;
  56                  */
  57                 bb_got_signal = 1;
  58         }
  59 }
  60
  61 /* transformer(), more than meets the eye */
  62 #if BB_MMU
  63 void FAST_FUNC open_transformer(int fd,
  64         int check_signature,
  65         IF_DESKTOP(long long) int FAST_FUNC (*transformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd)
  66 )
  67 #else
  68 void FAST_FUNC open_transformer(int fd, const char *transform_prog)
  69 #endif
  70 {
  71         struct fd_pair fd_pipe;
  72         int pid;
  73
  74         xpiped_pair(fd_pipe);
  75         pid = BB_MMU ? xfork() : xvfork();
  76         if (pid == 0) {
  77                 /* Child */
  78                 close(fd_pipe.rd); /* we don't want to read from the parent */
  79                 // FIXME: error check?
  80 #if BB_MMU
  81                 {
  82                         IF_DESKTOP(long long) int r;
  83                         transformer_aux_data_t aux;
  84                         init_transformer_aux_data(&aux);
  85                         aux.check_signature = check_signature;
  86                         r = transformer(&aux, fd, fd_pipe.wr);
  87                         if (ENABLE_FEATURE_CLEAN_UP) {
  88                                 close(fd_pipe.wr); /* send EOF */
  89                                 close(fd);
  90                         }
  91                         /* must be _exit! bug was actually seen here */
  92                         _exit(/*error if:*/ r < 0);
  93                 }
  94 #else
  95                 {
  96                         char *argv[4];
  97                         xmove_fd(fd, 0);
  98                         xmove_fd(fd_pipe.wr, 1);
  99                         argv[0] = (char*)transform_prog;
 100                         argv[1] = (char*)"-cf";
 101                         argv[2] = (char*)"-";
 102                         argv[3] = NULL;
 103                         BB_EXECVP(transform_prog, argv);
 104                         bb_perror_msg_and_die("can't execute '%s'", transform_prog);
 105                 }
 106 #endif
 107                 /* notreached */
 108         }
 109
 110         /* parent process */
 111         close(fd_pipe.wr); /* don't want to write to the child */
 112         xmove_fd(fd_pipe.rd, fd);
 113 }
 114
 115
 116 #if SEAMLESS_COMPRESSION
 117
 118 /* Used by e.g. rpm which gives us a fd without filename,
 119  * thus we can't guess the format from filename's extension.
 120  */
 121 int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_detected)
 122 {
 123         union {
 124                 uint8_t b[4];
 125                 uint16_t b16[2];
 126                 uint32_t b32[1];
 127         } magic;
 128         int offset = -2;
 129         USE_FOR_MMU(IF_DESKTOP(long long) int FAST_FUNC (*xformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd);)
 130         USE_FOR_NOMMU(const char *xformer_prog;)
 131
 132         /* .gz and .bz2 both have 2-byte signature, and their
 133          * unpack_XXX_stream wants this header skipped. */
 134         xread(fd, magic.b16, sizeof(magic.b16[0]));
 135         if (ENABLE_FEATURE_SEAMLESS_GZ
 136          && magic.b16[0] == GZIP_MAGIC
 137         ) {
 138                 USE_FOR_MMU(xformer = unpack_gz_stream;)
 139                 USE_FOR_NOMMU(xformer_prog = "gunzip";)
 140                 goto found_magic;
 141         }
 142         if (ENABLE_FEATURE_SEAMLESS_BZ2
 143          && magic.b16[0] == BZIP2_MAGIC
 144         ) {
 145                 USE_FOR_MMU(xformer = unpack_bz2_stream;)
 146                 USE_FOR_NOMMU(xformer_prog = "bunzip2";)
 147                 goto found_magic;
 148         }
 149         if (ENABLE_FEATURE_SEAMLESS_XZ
 150          && magic.b16[0] == XZ_MAGIC1
 151         ) {
 152                 offset = -6;
 153                 xread(fd, magic.b32, sizeof(magic.b32[0]));
 154                 if (magic.b32[0] == XZ_MAGIC2) {
 155                         USE_FOR_MMU(xformer = unpack_xz_stream;)
 156                         USE_FOR_NOMMU(xformer_prog = "unxz";)
 157                         goto found_magic;
 158                 }
 159         }
 160
 161         /* No known magic seen */
 162         if (fail_if_not_detected)
 163                 bb_error_msg_and_die("no gzip"
 164                         IF_FEATURE_SEAMLESS_BZ2("/bzip2")
 165                         IF_FEATURE_SEAMLESS_XZ("/xz")
 166                         " magic");
 167         xlseek(fd, offset, SEEK_CUR);
 168         return 1;
 169
 170  found_magic:
 171 # if BB_MMU
 172         open_transformer_with_no_sig(fd, xformer);
 173 # else
 174         /* NOMMU version of open_transformer execs
 175          * an external unzipper that wants
 176          * file position at the start of the file */
 177         xlseek(fd, offset, SEEK_CUR);
 178         open_transformer_with_sig(fd, xformer, xformer_prog);
 179 # endif
 180         return 0;
 181 }
 182
 183 int FAST_FUNC open_zipped(const char *fname)
 184 {
 185         int fd;
 186
 187         fd = open(fname, O_RDONLY);
 188         if (fd < 0)
 189                 return fd;
 190
 191         if (ENABLE_FEATURE_SEAMLESS_LZMA) {
 192                 /* .lzma has no header/signature, can only detect it by extension */
 193                 char *sfx = strrchr(fname, '.');
 194                 if (sfx && strcmp(sfx+1, "lzma") == 0) {
 195                         open_transformer_with_sig(fd, unpack_lzma_stream, "unlzma");
 196                         return fd;
 197                 }
 198         }
 199         if ((ENABLE_FEATURE_SEAMLESS_GZ)
 200          || (ENABLE_FEATURE_SEAMLESS_BZ2)
 201          || (ENABLE_FEATURE_SEAMLESS_XZ)
 202         ) {
 203                 setup_unzip_on_fd(fd, /*fail_if_not_detected:*/ 1);
 204         }
 205
 206         return fd;
 207 }
 208
 209 #endif /* SEAMLESS_COMPRESSION */
 210
 211 void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
 212 {
 213         int fd;
 214         char *image;
 215
 216         fd = open_zipped(fname);
 217         if (fd < 0)
 218                 return NULL;
 219
 220         image = xmalloc_read(fd, maxsz_p);
 221         if (!image)
 222                 bb_perror_msg("read error from '%s'", fname);
 223         close(fd);
 224
 225         return image;
 226 }