archival/libarchive/data_extract_to_command.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 enum {
  10         //TAR_FILETYPE,
  11         TAR_MODE,
  12         TAR_FILENAME,
  13         TAR_REALNAME,
  14 #if ENABLE_FEATURE_TAR_UNAME_GNAME
  15         TAR_UNAME,
  16         TAR_GNAME,
  17 #endif
  18         TAR_SIZE,
  19         TAR_UID,
  20         TAR_GID,
  21         TAR_MAX,
  22 };
  23
  24 static const char *const tar_var[] = {
  25         // "FILETYPE",
  26         "MODE",
  27         "FILENAME",
  28         "REALNAME",
  29 #if ENABLE_FEATURE_TAR_UNAME_GNAME
  30         "UNAME",
  31         "GNAME",
  32 #endif
  33         "SIZE",
  34         "UID",
  35         "GID",
  36 };
  37
  38 static void xputenv(char *str)
  39 {
  40         if (putenv(str))
  41                 bb_error_msg_and_die(bb_msg_memory_exhausted);
  42 }
  43
  44 static void str2env(char *env[], int idx, const char *str)
  45 {
  46         env[idx] = xasprintf("TAR_%s=%s", tar_var[idx], str);
  47         xputenv(env[idx]);
  48 }
  49
  50 static void dec2env(char *env[], int idx, unsigned long long val)
  51 {
  52         env[idx] = xasprintf("TAR_%s=%llu", tar_var[idx], val);
  53         xputenv(env[idx]);
  54 }
  55
  56 static void oct2env(char *env[], int idx, unsigned long val)
  57 {
  58         env[idx] = xasprintf("TAR_%s=%lo", tar_var[idx], val);
  59         xputenv(env[idx]);
  60 }
  61
  62 void FAST_FUNC data_extract_to_command(archive_handle_t *archive_handle)
  63 {
  64         file_header_t *file_header = archive_handle->file_header;
  65
  66 #if 0 /* do we need this? ENABLE_FEATURE_TAR_SELINUX */
  67         char *sctx = archive_handle->tar__sctx[PAX_NEXT_FILE];
  68         if (!sctx)
  69                 sctx = archive_handle->tar__sctx[PAX_GLOBAL];
  70         if (sctx) { /* setfscreatecon is 4 syscalls, avoid if possible */
  71                 setfscreatecon(sctx);
  72                 free(archive_handle->tar__sctx[PAX_NEXT_FILE]);
  73                 archive_handle->tar__sctx[PAX_NEXT_FILE] = NULL;
  74         }
  75 #endif
  76
  77         if ((file_header->mode & S_IFMT) == S_IFREG) {
  78                 pid_t pid;
  79                 int p[2], status;
  80                 char *tar_env[TAR_MAX];
  81
  82                 memset(tar_env, 0, sizeof(tar_env));
  83
  84                 xpipe(p);
  85                 pid = BB_MMU ? xfork() : xvfork();
  86                 if (pid == 0) {
  87                         /* Child */
  88                         /* str2env(tar_env, TAR_FILETYPE, "f"); - parent should do it once */
  89                         oct2env(tar_env, TAR_MODE, file_header->mode);
  90                         str2env(tar_env, TAR_FILENAME, file_header->name);
  91                         str2env(tar_env, TAR_REALNAME, file_header->name);
  92 #if ENABLE_FEATURE_TAR_UNAME_GNAME
  93                         str2env(tar_env, TAR_UNAME, file_header->tar__uname);
  94                         str2env(tar_env, TAR_GNAME, file_header->tar__gname);
  95 #endif
  96                         dec2env(tar_env, TAR_SIZE, file_header->size);
  97                         dec2env(tar_env, TAR_UID, file_header->uid);
  98                         dec2env(tar_env, TAR_GID, file_header->gid);
  99                         close(p[1]);
 100                         xdup2(p[0], STDIN_FILENO);
 101                         signal(SIGPIPE, SIG_DFL);
 102                         execl(archive_handle->tar__to_command_shell,
 103                                 archive_handle->tar__to_command_shell,
 104                                 "-c",
 105                                 archive_handle->tar__to_command,
 106                                 NULL);
 107                         bb_perror_msg_and_die("can't execute '%s'", archive_handle->tar__to_command_shell);
 108                 }
 109                 close(p[0]);
 110                 /* Our caller is expected to do signal(SIGPIPE, SIG_IGN)
 111                  * so that we don't die if child don't read all the input: */
 112                 bb_copyfd_exact_size(archive_handle->src_fd, p[1], -file_header->size);
 113                 close(p[1]);
 114
 115                 if (safe_waitpid(pid, &status, 0) == -1)
 116                         bb_perror_msg_and_die("waitpid");
 117                 if (WIFEXITED(status) && WEXITSTATUS(status))
 118                         bb_error_msg_and_die("'%s' returned status %d",
 119                                 archive_handle->tar__to_command, WEXITSTATUS(status));
 120                 if (WIFSIGNALED(status))
 121                         bb_error_msg_and_die("'%s' terminated on signal %d",
 122                                 archive_handle->tar__to_command, WTERMSIG(status));
 123
 124                 if (!BB_MMU) {
 125                         int i;
 126                         for (i = 0; i < TAR_MAX; i++) {
 127                                 if (tar_env[i])
 128                                         bb_unsetenv_and_free(tar_env[i]);
 129                         }
 130                 }
 131         }
 132
 133 #if 0 /* ENABLE_FEATURE_TAR_SELINUX */
 134         if (sctx)
 135                 /* reset the context after creating an entry */
 136                 setfscreatecon(NULL);
 137 #endif
 138 }