#include <stdio.h>
  #include <stdlib.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <string.h>
  #include <unistd.h>
  #include <time.h>
  #include <fcntl.h>
  #include <errno.h>
  #include <ctype.h>
  #include <limits.h>
  
  /*
   * Original work by Jeff Garzik
   *
   * External file lists, symlink, pipe and fifo support by Thayne Harbaugh

   * Hard link support by Luciano Rocha

   */
  
  #define xstr(s) #s
  #define str(s) xstr(s)
  
  static unsigned int offset;
  static unsigned int ino = 721;
  
  struct file_handler {
  	const char *type;
  	int (*handler)(const char *line);
  };
  
  static void push_string(const char *name)
  {
  	unsigned int name_len = strlen(name) + 1;
  
  	fputs(name, stdout);
  	putchar(0);
  	offset += name_len;
  }
  
  static void push_pad (void)
  {
  	while (offset & 3) {
  		putchar(0);
  		offset++;
  	}
  }
  
  static void push_rest(const char *name)
  {
  	unsigned int name_len = strlen(name) + 1;
  	unsigned int tmp_ofs;
  
  	fputs(name, stdout);
  	putchar(0);
  	offset += name_len;
  
  	tmp_ofs = name_len + 110;
  	while (tmp_ofs & 3) {
  		putchar(0);
  		offset++;
  		tmp_ofs++;
  	}
  }
  
  static void push_hdr(const char *s)
  {
  	fputs(s, stdout);
  	offset += 110;
  }
  
  static void cpio_trailer(void)
  {
  	char s[256];
  	const char name[] = "TRAILER!!!";
  
  	sprintf(s, "%s%08X%08X%08lX%08lX%08X%08lX"
  	       "%08X%08X%08X%08X%08X%08X%08X",
  		"070701",		/* magic */
  		0,			/* ino */
  		0,			/* mode */
  		(long) 0,		/* uid */
  		(long) 0,		/* gid */
  		1,			/* nlink */
  		(long) 0,		/* mtime */
  		0,			/* filesize */
  		0,			/* major */
  		0,			/* minor */
  		0,			/* rmajor */
  		0,			/* rminor */
  		(unsigned)strlen(name)+1, /* namesize */
  		0);			/* chksum */
  	push_hdr(s);
  	push_rest(name);
  
  	while (offset % 512) {
  		putchar(0);
  		offset++;
  	}
  }
  
  static int cpio_mkslink(const char *name, const char *target,
  			 unsigned int mode, uid_t uid, gid_t gid)
  {
  	char s[256];
  	time_t mtime = time(NULL);
  
  	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  	       "%08X%08X%08X%08X%08X%08X%08X",
  		"070701",		/* magic */
  		ino++,			/* ino */
  		S_IFLNK | mode,		/* mode */
  		(long) uid,		/* uid */
  		(long) gid,		/* gid */
  		1,			/* nlink */
  		(long) mtime,		/* mtime */
  		(unsigned)strlen(target)+1, /* filesize */
  		3,			/* major */
  		1,			/* minor */
  		0,			/* rmajor */
  		0,			/* rminor */
  		(unsigned)strlen(name) + 1,/* namesize */
  		0);			/* chksum */
  	push_hdr(s);
  	push_string(name);
  	push_pad();
  	push_string(target);
  	push_pad();
  	return 0;
  }
  
  static int cpio_mkslink_line(const char *line)
  {
  	char name[PATH_MAX + 1];
  	char target[PATH_MAX + 1];
  	unsigned int mode;
  	int uid;
  	int gid;
  	int rc = -1;
  
  	if (5 != sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX) "s %o %d %d", name, target, &mode, &uid, &gid)) {
  		fprintf(stderr, "Unrecognized dir format '%s'", line);
  		goto fail;
  	}
  	rc = cpio_mkslink(name, target, mode, uid, gid);
   fail:
  	return rc;
  }
  
  static int cpio_mkgeneric(const char *name, unsigned int mode,
  		       uid_t uid, gid_t gid)
  {
  	char s[256];
  	time_t mtime = time(NULL);
  
  	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  	       "%08X%08X%08X%08X%08X%08X%08X",
  		"070701",		/* magic */
  		ino++,			/* ino */
  		mode,			/* mode */
  		(long) uid,		/* uid */
  		(long) gid,		/* gid */
  		2,			/* nlink */
  		(long) mtime,		/* mtime */
  		0,			/* filesize */
  		3,			/* major */
  		1,			/* minor */
  		0,			/* rmajor */
  		0,			/* rminor */
  		(unsigned)strlen(name) + 1,/* namesize */
  		0);			/* chksum */
  	push_hdr(s);
  	push_rest(name);
  	return 0;
  }
  
  enum generic_types {
  	GT_DIR,
  	GT_PIPE,
  	GT_SOCK
  };
  
  struct generic_type {
  	const char *type;
  	mode_t mode;
  };
  
  static struct generic_type generic_type_table[] = {
  	[GT_DIR] = {
  		.type = "dir",
  		.mode = S_IFDIR
  	},
  	[GT_PIPE] = {
  		.type = "pipe",
  		.mode = S_IFIFO
  	},
  	[GT_SOCK] = {
  		.type = "sock",
  		.mode = S_IFSOCK
  	}
  };
  
  static int cpio_mkgeneric_line(const char *line, enum generic_types gt)
  {
  	char name[PATH_MAX + 1];
  	unsigned int mode;
  	int uid;
  	int gid;
  	int rc = -1;
  
  	if (4 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d", name, &mode, &uid, &gid)) {
  		fprintf(stderr, "Unrecognized %s format '%s'",
  			line, generic_type_table[gt].type);
  		goto fail;
  	}
  	mode |= generic_type_table[gt].mode;
  	rc = cpio_mkgeneric(name, mode, uid, gid);
   fail:
  	return rc;
  }
  
  static int cpio_mkdir_line(const char *line)
  {
  	return cpio_mkgeneric_line(line, GT_DIR);
  }
  
  static int cpio_mkpipe_line(const char *line)
  {
  	return cpio_mkgeneric_line(line, GT_PIPE);
  }
  
  static int cpio_mksock_line(const char *line)
  {
  	return cpio_mkgeneric_line(line, GT_SOCK);
  }
  
  static int cpio_mknod(const char *name, unsigned int mode,
  		       uid_t uid, gid_t gid, char dev_type,
  		       unsigned int maj, unsigned int min)
  {
  	char s[256];
  	time_t mtime = time(NULL);
  
  	if (dev_type == 'b')
  		mode |= S_IFBLK;
  	else
  		mode |= S_IFCHR;
  
  	sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  	       "%08X%08X%08X%08X%08X%08X%08X",
  		"070701",		/* magic */
  		ino++,			/* ino */
  		mode,			/* mode */
  		(long) uid,		/* uid */
  		(long) gid,		/* gid */
  		1,			/* nlink */
  		(long) mtime,		/* mtime */
  		0,			/* filesize */
  		3,			/* major */
  		1,			/* minor */
  		maj,			/* rmajor */
  		min,			/* rminor */
  		(unsigned)strlen(name) + 1,/* namesize */
  		0);			/* chksum */
  	push_hdr(s);
  	push_rest(name);
  	return 0;
  }
  
  static int cpio_mknod_line(const char *line)
  {
  	char name[PATH_MAX + 1];
  	unsigned int mode;
  	int uid;
  	int gid;
  	char dev_type;
  	unsigned int maj;
  	unsigned int min;
  	int rc = -1;
  
  	if (7 != sscanf(line, "%" str(PATH_MAX) "s %o %d %d %c %u %u",
  			 name, &mode, &uid, &gid, &dev_type, &maj, &min)) {
  		fprintf(stderr, "Unrecognized nod format '%s'", line);
  		goto fail;
  	}
  	rc = cpio_mknod(name, mode, uid, gid, dev_type, maj, min);
   fail:
  	return rc;
  }

  static int cpio_mkfile(const char *name, const char *location,

  			unsigned int mode, uid_t uid, gid_t gid,
  			unsigned int nlinks)

  {
  	char s[256];
  	char *filebuf = NULL;
  	struct stat buf;

  	long size;

  	int file = -1;
  	int retval;
  	int rc = -1;

  	int namesize;
  	int i;

  
  	mode |= S_IFREG;
  
  	retval = stat (location, &buf);
  	if (retval) {
  		fprintf (stderr, "File %s could not be located
  ", location);
  		goto error;
  	}
  
  	file = open (location, O_RDONLY);
  	if (file < 0) {
  		fprintf (stderr, "File %s could not be opened for reading
  ", location);
  		goto error;
  	}
  
  	filebuf = malloc(buf.st_size);
  	if (!filebuf) {
  		fprintf (stderr, "out of memory
  ");
  		goto error;
  	}
  
  	retval = read (file, filebuf, buf.st_size);
  	if (retval < 0) {
  		fprintf (stderr, "Can not read %s file
  ", location);
  		goto error;
  	}

  	size = 0;
  	for (i = 1; i <= nlinks; i++) {
  		/* data goes on last link */
  		if (i == nlinks) size = buf.st_size;
  
  		namesize = strlen(name) + 1;
  		sprintf(s,"%s%08X%08X%08lX%08lX%08X%08lX"
  		       "%08lX%08X%08X%08X%08X%08X%08X",
  			"070701",		/* magic */
  			ino,			/* ino */
  			mode,			/* mode */
  			(long) uid,		/* uid */
  			(long) gid,		/* gid */
  			nlinks,			/* nlink */
  			(long) buf.st_mtime,	/* mtime */
  			size,			/* filesize */
  			3,			/* major */
  			1,			/* minor */
  			0,			/* rmajor */
  			0,			/* rminor */
  			namesize,		/* namesize */
  			0);			/* chksum */
  		push_hdr(s);
  		push_string(name);
  		push_pad();
  
  		if (size) {

  			if (fwrite(filebuf, size, 1, stdout) != 1) {
  				fprintf(stderr, "writing filebuf failed
  ");
  				goto error;
  			}

  			offset += size;
  			push_pad();
  		}
  
  		name += namesize;
  	}
  	ino++;

  	rc = 0;
  	
  error:
  	if (filebuf) free(filebuf);
  	if (file >= 0) close(file);
  	return rc;
  }

  static char *cpio_replace_env(char *new_location)
  {
         char expanded[PATH_MAX + 1];
         char env_var[PATH_MAX + 1];
         char *start;
         char *end;
  
         for (start = NULL; (start = strstr(new_location, "${")); ) {
                 end = strchr(start, '}');
                 if (start < end) {
                         *env_var = *expanded = '\0';
                         strncat(env_var, start + 2, end - start - 2);
                         strncat(expanded, new_location, start - new_location);
                         strncat(expanded, getenv(env_var), PATH_MAX);
                         strncat(expanded, end + 1, PATH_MAX);
                         strncpy(new_location, expanded, PATH_MAX);
                 } else
                         break;
         }
  
         return new_location;
  }

  static int cpio_mkfile_line(const char *line)
  {
  	char name[PATH_MAX + 1];

  	char *dname = NULL; /* malloc'ed buffer for hard links */

  	char location[PATH_MAX + 1];
  	unsigned int mode;
  	int uid;
  	int gid;

  	int nlinks = 1;
  	int end = 0, dname_len = 0;

  	int rc = -1;

  	if (5 > sscanf(line, "%" str(PATH_MAX) "s %" str(PATH_MAX)
  				"s %o %d %d %n",
  				name, location, &mode, &uid, &gid, &end)) {

  		fprintf(stderr, "Unrecognized file format '%s'", line);
  		goto fail;
  	}

  	if (end && isgraph(line[end])) {
  		int len;
  		int nend;
  
  		dname = malloc(strlen(line));
  		if (!dname) {
  			fprintf (stderr, "out of memory (%d)
  ", dname_len);
  			goto fail;
  		}
  
  		dname_len = strlen(name) + 1;
  		memcpy(dname, name, dname_len);
  
  		do {
  			nend = 0;
  			if (sscanf(line + end, "%" str(PATH_MAX) "s %n",
  					name, &nend) < 1)
  				break;
  			len = strlen(name) + 1;
  			memcpy(dname + dname_len, name, len);
  			dname_len += len;
  			nlinks++;
  			end += nend;
  		} while (isgraph(line[end]));
  	} else {
  		dname = name;
  	}

  	rc = cpio_mkfile(dname, cpio_replace_env(location),
  	                 mode, uid, gid, nlinks);

   fail:

  	if (dname_len) free(dname);

  	return rc;
  }

  static void usage(const char *prog)

  {
  	fprintf(stderr, "Usage:
  "
  		"\t%s <cpio_list>
  "
  		"
  "
  		"<cpio_list> is a file containing newline separated entries that
  "
  		"describe the files to be included in the initramfs archive:
  "
  		"
  "
  		"# a comment
  "

  		"file <name> <location> <mode> <uid> <gid> [<hard links>]
  "

  		"dir <name> <mode> <uid> <gid>
  "
  		"nod <name> <mode> <uid> <gid> <dev_type> <maj> <min>
  "
  		"slink <name> <target> <mode> <uid> <gid>
  "
  		"pipe <name> <mode> <uid> <gid>
  "
  		"sock <name> <mode> <uid> <gid>
  "
  		"
  "

  		"<name>       name of the file/dir/nod/etc in the archive
  "
  		"<location>   location of the file in the current filesystem
  "

  		"             expands shell variables quoted with ${}
  "

  		"<target>     link target
  "
  		"<mode>       mode/permissions of the file
  "
  		"<uid>        user id (0=root)
  "
  		"<gid>        group id (0=root)
  "
  		"<dev_type>   device type (b=block, c=character)
  "
  		"<maj>        major number of nod
  "
  		"<min>        minor number of nod
  "
  		"<hard links> space separated list of other links to file
  "

  		"
  "
  		"example:
  "
  		"# A simple initramfs
  "
  		"dir /dev 0755 0 0
  "
  		"nod /dev/console 0600 0 0 c 5 1
  "
  		"dir /root 0700 0 0
  "
  		"dir /sbin 0755 0 0
  "
  		"file /sbin/kinit /usr/src/klibc/kinit/kinit 0755 0 0
  ",
  		prog);
  }
  
  struct file_handler file_handler_table[] = {
  	{
  		.type    = "file",
  		.handler = cpio_mkfile_line,
  	}, {
  		.type    = "nod",
  		.handler = cpio_mknod_line,
  	}, {
  		.type    = "dir",
  		.handler = cpio_mkdir_line,
  	}, {
  		.type    = "slink",
  		.handler = cpio_mkslink_line,
  	}, {
  		.type    = "pipe",
  		.handler = cpio_mkpipe_line,
  	}, {
  		.type    = "sock",
  		.handler = cpio_mksock_line,
  	}, {
  		.type    = NULL,
  		.handler = NULL,
  	}
  };
  
  #define LINE_SIZE (2 * PATH_MAX + 50)
  
  int main (int argc, char *argv[])
  {
  	FILE *cpio_list;
  	char line[LINE_SIZE];
  	char *args, *type;
  	int ec = 0;
  	int line_nr = 0;
  
  	if (2 != argc) {
  		usage(argv[0]);
  		exit(1);
  	}

  	if (!strcmp(argv[1], "-"))
  		cpio_list = stdin;
  	else if (! (cpio_list = fopen(argv[1], "r"))) {

  		fprintf(stderr, "ERROR: unable to open '%s': %s
  
  ",
  			argv[1], strerror(errno));
  		usage(argv[0]);
  		exit(1);
  	}
  
  	while (fgets(line, LINE_SIZE, cpio_list)) {
  		int type_idx;
  		size_t slen = strlen(line);
  
  		line_nr++;
  
  		if ('#' == *line) {
  			/* comment - skip to next line */
  			continue;
  		}
  
  		if (! (type = strtok(line, " \t"))) {
  			fprintf(stderr,
  				"ERROR: incorrect format, could not locate file type line %d: '%s'
  ",
  				line_nr, line);
  			ec = -1;

  			break;

  		}
  
  		if ('
  ' == *type) {
  			/* a blank line */
  			continue;
  		}
  
  		if (slen == strlen(type)) {
  			/* must be an empty line */
  			continue;
  		}
  
  		if (! (args = strtok(NULL, "
  "))) {
  			fprintf(stderr,
  				"ERROR: incorrect format, newline required line %d: '%s'
  ",
  				line_nr, line);
  			ec = -1;
  		}
  
  		for (type_idx = 0; file_handler_table[type_idx].type; type_idx++) {
  			int rc;
  			if (! strcmp(line, file_handler_table[type_idx].type)) {
  				if ((rc = file_handler_table[type_idx].handler(args))) {
  					ec = rc;
  					fprintf(stderr, " line %d
  ", line_nr);
  				}
  				break;
  			}
  		}
  
  		if (NULL == file_handler_table[type_idx].type) {
  			fprintf(stderr, "unknown file type line %d: '%s'
  ",
  				line_nr, line);
  		}
  	}

  	if (ec == 0)
  		cpio_trailer();

  
  	exit(ec);
  }