LXR busybox/archival/libarchive/get_header

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Copyright 2002 Laurence Anderson
   4 *
   5 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   6 */
   7#include "libbb.h"
   8#include "bb_archive.h"
   9
  10typedef struct hardlinks_t {
  11        struct hardlinks_t *next;
  12        int inode; /* TODO: must match maj/min too! */
  13        int mode ;
  14        int mtime; /* These three are useful only in corner case */
  15        int uid  ; /* of hardlinks with zero size body */
  16        int gid  ;
  17        char name[1];
  18} hardlinks_t;
  19
  20char FAST_FUNC get_header_cpio(archive_handle_t *archive_handle)
  21{
  22        file_header_t *file_header = archive_handle->file_header;
  23        char cpio_header[111];
  24        int namesize;
  25        int major, minor, nlink, mode, inode;
  26        unsigned size, uid, gid, mtime;
  27
  28        /* There can be padding before archive header */
  29        data_align(archive_handle, 4);
  30
  31        size = full_read(archive_handle->src_fd, cpio_header, 110);
  32        if (size == 0) {
  33                goto create_hardlinks;
  34        }
  35        if (size != 110) {
  36                bb_simple_error_msg_and_die("short read");
  37        }
  38        archive_handle->offset += 110;
  39
  40        if (!is_prefixed_with(&cpio_header[0], "07070")
  41         || (cpio_header[5] != '1' && cpio_header[5] != '2')
  42        ) {
  43                bb_simple_error_msg_and_die("unsupported cpio format, use newc or crc");
  44        }
  45
  46        cpio_header[110] = '\0'; /* sscanf may call strlen which may break without this */
  47        if (sscanf(cpio_header + 6,
  48                        "%8x" "%8x" "%8x" "%8x"
  49                        "%8x" "%8x" "%8x" /*maj,min:*/ "%*16c"
  50                        /*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum: "%*8c"*/,
  51                        &inode, &mode, &uid, &gid,
  52                        &nlink, &mtime, &size,
  53                        &major, &minor, &namesize) != 10)
  54                bb_simple_error_msg_and_die("damaged cpio file");
  55        file_header->mode = mode;
  56        /* "cpio -R USER:GRP" support: */
  57        if (archive_handle->cpio__owner.uid != (uid_t)-1L)
  58                uid = archive_handle->cpio__owner.uid;
  59        if (archive_handle->cpio__owner.gid != (gid_t)-1L)
  60                gid = archive_handle->cpio__owner.gid;
  61        file_header->uid = uid;
  62        file_header->gid = gid;
  63        file_header->mtime = mtime;
  64        file_header->size = size;
  65
  66        namesize &= 0x1fff; /* paranoia: limit names to 8k chars */
  67        file_header->name = xzalloc(namesize + 1);
  68        /* Read in filename */
  69        xread(archive_handle->src_fd, file_header->name, namesize);
  70        if (file_header->name[0] == '/') {
  71                /* Testcase: echo /etc/hosts | cpio -pvd /tmp
  72                 * Without this code, it tries to unpack /etc/hosts
  73                 * into "/etc/hosts", not "etc/hosts".
  74                 */
  75                char *p = file_header->name;
  76                do p++; while (*p == '/');
  77                overlapping_strcpy(file_header->name, p);
  78        }
  79        archive_handle->offset += namesize;
  80
  81        /* Update offset amount and skip padding before file contents */
  82        data_align(archive_handle, 4);
  83
  84        if (strcmp(file_header->name, cpio_TRAILER) == 0) {
  85                /* Always round up. ">> 9" divides by 512 */
  86                archive_handle->cpio__blocks = (uoff_t)(archive_handle->offset + 511) >> 9;
  87                goto create_hardlinks;
  88        }
  89
  90        file_header->link_target = NULL;
  91        if (S_ISLNK(file_header->mode)) {
  92                file_header->size &= 0x1fff; /* paranoia: limit names to 8k chars */
  93                file_header->link_target = xzalloc(file_header->size + 1);
  94                xread(archive_handle->src_fd, file_header->link_target, file_header->size);
  95                archive_handle->offset += file_header->size;
  96                file_header->size = 0; /* Stop possible seeks in future */
  97        }
  98
  99// TODO: data_extract_all can't deal with hardlinks to non-files...
 100// when fixed, change S_ISREG to !S_ISDIR here
 101
 102        if (nlink > 1 && S_ISREG(file_header->mode)) {
 103                hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
 104                new->inode = inode;
 105                new->mode  = mode ;
 106                new->mtime = mtime;
 107                new->uid   = uid  ;
 108                new->gid   = gid  ;
 109                strcpy(new->name, file_header->name);
 110                /* Put file on a linked list for later */
 111                if (size == 0) {
 112                        new->next = archive_handle->cpio__hardlinks_to_create;
 113                        archive_handle->cpio__hardlinks_to_create = new;
 114                        return EXIT_SUCCESS; /* Skip this one */
 115                        /* TODO: this breaks cpio -t (it does not show hardlinks) */
 116                }
 117                new->next = archive_handle->cpio__created_hardlinks;
 118                archive_handle->cpio__created_hardlinks = new;
 119        }
 120        file_header->device = makedev(major, minor);
 121
 122        if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 123                archive_handle->action_data(archive_handle);
 124//TODO: run "echo /etc/hosts | cpio -pv /tmp" twice. On 2nd run:
 125//cpio: etc/hosts not created: newer or same age file exists
 126//etc/hosts  <-- should NOT show it
 127//2 blocks <-- should say "0 blocks"
 128                archive_handle->action_header(file_header);
 129        } else {
 130                data_skip(archive_handle);
 131        }
 132
 133        archive_handle->offset += file_header->size;
 134
 135        free(file_header->link_target);
 136        free(file_header->name);
 137        file_header->link_target = NULL;
 138        file_header->name = NULL;
 139
 140        return EXIT_SUCCESS;
 141
 142 create_hardlinks:
 143        free(file_header->link_target);
 144        free(file_header->name);
 145
 146        while (archive_handle->cpio__hardlinks_to_create) {
 147                hardlinks_t *cur;
 148                hardlinks_t *make_me = archive_handle->cpio__hardlinks_to_create;
 149
 150                archive_handle->cpio__hardlinks_to_create = make_me->next;
 151
 152                memset(file_header, 0, sizeof(*file_header));
 153                file_header->mtime = make_me->mtime;
 154                file_header->name = make_me->name;
 155                file_header->mode = make_me->mode;
 156                file_header->uid = make_me->uid;
 157                file_header->gid = make_me->gid;
 158                /*file_header->size = 0;*/
 159                /*file_header->link_target = NULL;*/
 160
 161                /* Try to find a file we are hardlinked to */
 162                cur = archive_handle->cpio__created_hardlinks;
 163                while (cur) {
 164                        /* TODO: must match maj/min too! */
 165                        if (cur->inode == make_me->inode) {
 166                                file_header->link_target = cur->name;
 167                                 /* link_target != NULL, size = 0: "I am a hardlink" */
 168                                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 169                                        archive_handle->action_data(archive_handle);
 170                                free(make_me);
 171                                goto next_link;
 172                        }
 173                        cur = cur->next;
 174                }
 175                /* Oops... no file with such inode was created... do it now
 176                 * (happens when hardlinked files are empty (zero length)) */
 177                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 178                        archive_handle->action_data(archive_handle);
 179                /* Move to the list of created hardlinked files */
 180                make_me->next = archive_handle->cpio__created_hardlinks;
 181                archive_handle->cpio__created_hardlinks = make_me;
 182 next_link: ;
 183        }
 184
 185        while (archive_handle->cpio__created_hardlinks) {
 186                hardlinks_t *p = archive_handle->cpio__created_hardlinks;
 187                archive_handle->cpio__created_hardlinks = p->next;
 188                free(p);
 189        }
 190
 191        return EXIT_FAILURE; /* "No more files to process" */
 192}
 193