LXR busybox/archival/libunarchive/get_header

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