/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2007 H. Peter Anvin - All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

/*
 * initramfs_file.c
 *
 * Utility functions to add arbitrary files including cpio header
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <syslinux/linux.h>

#define CPIO_MAGIC "070701"
struct cpio_header {
  char c_magic[6];		/* 070701 */
  char c_ino[8];		/* Inode number */
  char c_mode[8];		/* File mode and permissions */
  char c_uid[8];		/* uid */
  char c_gid[8];		/* gid */
  char c_nlink[8];		/* Number of links */
  char c_mtime[8];		/* Modification time */
  char c_filesize[8];		/* Size of data field */
  char c_maj[8];		/* File device major number */
  char c_min[8];		/* File device minor number */
  char c_rmaj[8];		/* Device node reference major number */
  char c_rmin[8];		/* Device node reference minor number */
  char c_namesize[8];		/* Length of filename including final \0 */
  char c_chksum[8];		/* Checksum if c_magic ends in 2 */
};

static uint32_t next_ino = 1;

/* Create cpio headers for the directory entries leading up to a file.
   Returns the number of bytes; doesn't touch the buffer if too small. */
static size_t initramfs_mkdirs(const char *filename, void *buffer,
			       size_t buflen)
{
  const char *p = filename;
  char *bp = buffer;
  int len;
  size_t bytes = 0;
  int pad;

  while ((p = strchr(p, '/'))) {
    if (p != filename && p[-1] != '/') {
      len = p-filename;
      bytes += ((sizeof(struct cpio_header)+len+1)+3) & ~3;
    }
    p++;
  }

  if (buflen >= bytes) {
    p = filename;
    while ((p = strchr(p, '/'))) {
      if (p != filename && p[-1] != '/') {
	len = p-filename;
	bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x"
		      "%08x%08x%08x%08x", next_ino++, S_IFDIR|0755,
		      0, 0, 1, 0, 0, 0, 1, 0, 1, len+1, 0);
	memcpy(bp, filename, len);
	bp += len;
	pad = (-(sizeof(struct cpio_header)+len) & 3) + 1;
	memset(bp, 0, pad);
	bp += pad;
      }
    }
  }

  return bytes;
}

/*
 * Create a file header (with optional parent directory entries)
 * and add it to an initramfs chain
 */
int initramfs_mknod(struct initramfs *ihead, const char *filename,
		    int do_mkdir,
		    uint16_t mode, size_t len,
		    uint32_t major, uint32_t minor)
{
  size_t bytes;
  int namelen = strlen(filename);
  int pad;
  char *buffer, *bp;

  if (do_mkdir)
    bytes = initramfs_mkdirs(filename, NULL, 0);
  else
    bytes = 0;

  bytes += ((sizeof(struct cpio_header)+namelen+1)+3) & ~3;

  bp = buffer = malloc(bytes);
  if (!buffer)
    return -1;

  if (do_mkdir)
    bp += initramfs_mkdirs(filename, bp, bytes);

  bp += sprintf(bp, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x"
		"%08x%08x%08x%08x", next_ino++, mode,
		0, 0, 1, 0, len, 0, 1, major, minor, namelen+1, 0);
  memcpy(bp, filename, namelen);
  bp += len;
  pad = (-(sizeof(struct cpio_header)+namelen) & 3) + 1;
  memset(bp, 0, pad);

  if (initramfs_add_data(ihead, buffer, bytes, bytes, 4)) {
    free(buffer);
    return -1;
  }

  return 0;
}

/*
 * Add a file given data in memory to an initramfs chain.  This
 * can be used to create nonfiles like symlinks by specifying an
 * appropriate mode.
 */
int initramfs_add_file(struct initramfs *ihead, const void *data,
		       size_t data_len, size_t len,
		       const char *filename, int do_mkdir, uint32_t mode)
{
  if (initramfs_mknod(ihead, filename, do_mkdir,
		      (mode & S_IFMT) ? mode : mode|S_IFREG,
		      len, 0, 1))
    return -1;

  return initramfs_add_data(ihead, data, data_len, len, 4);
}

int initramfs_add_trailer(struct initramfs *ihead)
{
  return initramfs_mknod(ihead, "TRAILER!!!", 0, 0, 0, 0, 0);
}
