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