com32/lib/syslinux/initramfs_file.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2007-2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 /*
  29  * initramfs_file.c
  30  *
  31  * Utility functions to add arbitrary files including cpio header
  32  */
  33
  34 #include <stdlib.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37 #include <sys/stat.h>
  38 #include <syslinux/linux.h>
  39
  40 #define CPIO_MAGIC "070701"
  41 struct cpio_header {
  42     char c_magic[6];            /* 070701 */
  43     char c_ino[8];              /* Inode number */
  44     char c_mode[8];             /* File mode and permissions */
  45     char c_uid[8];              /* uid */
  46     char c_gid[8];              /* gid */
  47     char c_nlink[8];            /* Number of links */
  48     char c_mtime[8];            /* Modification time */
  49     char c_filesize[8];         /* Size of data field */
  50     char c_maj[8];              /* File device major number */
  51     char c_min[8];              /* File device minor number */
  52     char c_rmaj[8];             /* Device node reference major number */
  53     char c_rmin[8];             /* Device node reference minor number */
  54     char c_namesize[8];         /* Length of filename including final \0 */
  55     char c_chksum[8];           /* Checksum if c_magic ends in 2 */
  56 };
  57
  58 static uint32_t next_ino = 1;
  59
  60 /* Create cpio headers for the directory entries leading up to a file.
  61    Returns the number of bytes; doesn't touch the buffer if too small. */
  62 static size_t initramfs_mkdirs(const char *filename, void *buffer,
  63                                size_t buflen)
  64 {
  65     const char *p = filename;
  66     char *bp = buffer;
  67     int len;
  68     size_t bytes = 0, hdr_sz;
  69     int pad;
  70
  71     while ((p = strchr(p, '/'))) {
  72         if (p != filename && p[-1] != '/') {
  73             len = p - filename;
  74             bytes += ((sizeof(struct cpio_header) + len + 1) + 3) & ~3;
  75         }
  76         p++;
  77     }
  78
  79     if (buflen >= bytes) {
  80         p = filename;
  81         while ((p = strchr(p, '/'))) {
  82             if (p != filename && p[-1] != '/') {
  83                 len = p - filename;
  84                 hdr_sz = ((sizeof(struct cpio_header) + len + 1) + 3) & ~3;
  85                 bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x"
  86                               "%08x%08x%08x%08x", next_ino++, S_IFDIR | 0755,
  87                               0, 0, 1, 0, 0, 0, 1, 0, 1, len + 1, 0);
  88                 memcpy(bp, filename, len);
  89                 bp += len;
  90                 pad = hdr_sz - (sizeof(struct cpio_header) + len);
  91                 memset(bp, 0, pad);
  92                 bp += pad;
  93             }
  94             p++;
  95         }
  96     }
  97
  98     return bytes;
  99 }
 100
 101 /*
 102  * Create a file header (with optional parent directory entries)
 103  * and add it to an initramfs chain
 104  */
 105 int initramfs_mknod(struct initramfs *ihead, const char *filename,
 106                     int do_mkdir,
 107                     uint16_t mode, size_t len, uint32_t major, uint32_t minor)
 108 {
 109     size_t bytes, hdr_sz;
 110     int namelen = strlen(filename);
 111     int pad;
 112     char *buffer, *bp;
 113
 114     if (do_mkdir)
 115         bytes = initramfs_mkdirs(filename, NULL, 0);
 116     else
 117         bytes = 0;
 118
 119     hdr_sz = ((sizeof(struct cpio_header) + namelen + 1) + 3) & ~3;
 120     bytes += hdr_sz;
 121
 122     bp = buffer = malloc(bytes);
 123     if (!buffer)
 124         return -1;
 125
 126     if (do_mkdir)
 127         bp += initramfs_mkdirs(filename, bp, bytes);
 128
 129     bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08zx%08x%08x"
 130                   "%08x%08x%08x%08x", next_ino++, mode,
 131                   0, 0, 1, 0, len, 0, 1, major, minor, namelen + 1, 0);
 132     memcpy(bp, filename, namelen);
 133     bp += namelen;
 134     pad = hdr_sz - (sizeof(struct cpio_header) + namelen);
 135     memset(bp, 0, pad);
 136
 137     if (initramfs_add_data(ihead, buffer, bytes, bytes, 4)) {
 138         free(buffer);
 139         return -1;
 140     }
 141
 142     return 0;
 143 }
 144
 145 /*
 146  * Add a file given data in memory to an initramfs chain.  This
 147  * can be used to create nonfiles like symlinks by specifying an
 148  * appropriate mode.
 149  */
 150 int initramfs_add_file(struct initramfs *ihead, const void *data,
 151                        size_t data_len, size_t len,
 152                        const char *filename, int do_mkdir, uint32_t mode)
 153 {
 154     if (initramfs_mknod(ihead, filename, do_mkdir,
 155                         (mode & S_IFMT) ? mode : mode | S_IFREG, len, 0, 1))
 156         return -1;
 157
 158     return initramfs_add_data(ihead, data, data_len, len, 4);
 159 }
 160
 161 int initramfs_add_trailer(struct initramfs *ihead)
 162 {
 163     return initramfs_mknod(ihead, "TRAILER!!!", 0, 0, 0, 0, 0);
 164 }