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[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 (!is_prefixed_with(&cpio_header[0], "07070")
  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        /* "cpio -R USER:GRP" support: */
  56        if (archive_handle->cpio__owner.uid != (uid_t)-1L)
  57                uid = archive_handle->cpio__owner.uid;
  58        if (archive_handle->cpio__owner.gid != (gid_t)-1L)
  59                gid = archive_handle->cpio__owner.gid;
  60        file_header->uid = uid;
  61        file_header->gid = gid;
  62        file_header->mtime = mtime;
  63        file_header->size = size;
  64
  65        namesize &= 0x1fff; /* paranoia: limit names to 8k chars */
  66        file_header->name = xzalloc(namesize + 1);
  67        /* Read in filename */
  68        xread(archive_handle->src_fd, file_header->name, namesize);
  69        if (file_header->name[0] == '/') {
  70                /* Testcase: echo /etc/hosts | cpio -pvd /tmp
  71                 * Without this code, it tries to unpack /etc/hosts
  72                 * into "/etc/hosts", not "etc/hosts".
  73                 */
  74                char *p = file_header->name;
  75                do p++; while (*p == '/');
  76                overlapping_strcpy(file_header->name, p);
  77        }
  78        archive_handle->offset += namesize;
  79
  80        /* Update offset amount and skip padding before file contents */
  81        data_align(archive_handle, 4);
  82
  83        if (strcmp(file_header->name, cpio_TRAILER) == 0) {
  84                /* Always round up. ">> 9" divides by 512 */
  85                archive_handle->cpio__blocks = (uoff_t)(archive_handle->offset + 511) >> 9;
  86                goto create_hardlinks;
  87        }
  88
  89        file_header->link_target = NULL;
  90        if (S_ISLNK(file_header->mode)) {
  91                file_header->size &= 0x1fff; /* paranoia: limit names to 8k chars */
  92                file_header->link_target = xzalloc(file_header->size + 1);
  93                xread(archive_handle->src_fd, file_header->link_target, file_header->size);
  94                archive_handle->offset += file_header->size;
  95                file_header->size = 0; /* Stop possible seeks in future */
  96        }
  97
  98// TODO: data_extract_all can't deal with hardlinks to non-files...
  99// when fixed, change S_ISREG to !S_ISDIR here
 100
 101        if (nlink > 1 && S_ISREG(file_header->mode)) {
 102                hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
 103                new->inode = inode;
 104                new->mode  = mode ;
 105                new->mtime = mtime;
 106                new->uid   = uid  ;
 107                new->gid   = gid  ;
 108                strcpy(new->name, file_header->name);
 109                /* Put file on a linked list for later */
 110                if (size == 0) {
 111                        new->next = archive_handle->cpio__hardlinks_to_create;
 112                        archive_handle->cpio__hardlinks_to_create = new;
 113                        return EXIT_SUCCESS; /* Skip this one */
 114                        /* TODO: this breaks cpio -t (it does not show hardlinks) */
 115                }
 116                new->next = archive_handle->cpio__created_hardlinks;
 117                archive_handle->cpio__created_hardlinks = new;
 118        }
 119        file_header->device = makedev(major, minor);
 120
 121        if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
 122                archive_handle->action_data(archive_handle);
 123//TODO: run "echo /etc/hosts | cpio -pv /tmp" twice. On 2nd run:
 124//cpio: etc/hosts not created: newer or same age file exists
 125//etc/hosts  <-- should NOT show it
 126//2 blocks <-- should say "0 blocks"
 127                archive_handle->action_header(file_header);
 128        } else {
 129                data_skip(archive_handle);
 130        }
 131
 132        archive_handle->offset += file_header->size;
 133
 134        free(file_header->link_target);
 135        free(file_header->name);
 136        file_header->link_target = NULL;
 137        file_header->name = NULL;
 138
 139        return EXIT_SUCCESS;
 140
 141 create_hardlinks:
 142        free(file_header->link_target);
 143        free(file_header->name);
 144
 145        while (archive_handle->cpio__hardlinks_to_create) {
 146                hardlinks_t *cur;
 147                hardlinks_t *make_me = archive_handle->cpio__hardlinks_to_create;
 148
 149                archive_handle->cpio__hardlinks_to_create = make_me->next;
 150
 151                memset(file_header, 0, sizeof(*file_header));
 152                file_header->mtime = make_me->mtime;
 153                file_header->name = make_me->name;
 154                file_header->mode = make_me->mode;
 155                file_header->uid = make_me->uid;
 156                file_header->gid = make_me->gid;
 157                /*file_header->size = 0;*/
 158                /*file_header->link_target = NULL;*/
 159
 160                /* Try to find a file we are hardlinked to */
 161                cur = archive_handle->cpio__created_hardlinks;
 162                while (cur) {
 163                        /* TODO: must match maj/min too! */
 164                        if (cur->inode == make_me->inode) {
 165                                file_header->link_target = cur->name;
 166                                 /* link_target != NULL, size = 0: "I am a hardlink" */
 167                                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 168                                        archive_handle->action_data(archive_handle);
 169                                free(make_me);
 170                                goto next_link;
 171                        }
 172                        cur = cur->next;
 173                }
 174                /* Oops... no file with such inode was created... do it now
 175                 * (happens when hardlinked files are empty (zero length)) */
 176                if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
 177                        archive_handle->action_data(archive_handle);
 178                /* Move to the list of created hardlinked files */
 179                make_me->next = archive_handle->cpio__created_hardlinks;
 180                archive_handle->cpio__created_hardlinks = make_me;
 181 next_link: ;
 182        }
 183
 184        while (archive_handle->cpio__created_hardlinks) {
 185                hardlinks_t *p = archive_handle->cpio__created_hardlinks;
 186                archive_handle->cpio__created_hardlinks = p->next;
 187                free(p);
 188        }
 189
 190        return EXIT_FAILURE; /* "No more files to process" */
 191}
 192