/*
   * Copyright 2010-2011 Calxeda, Inc.
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */

  #include <common.h>
  #include <command.h>
  #include <malloc.h>
  #include <linux/string.h>
  #include <linux/ctype.h>
  #include <errno.h>
  #include <linux/list.h>

  #include <fs.h>

  
  #include "menu.h"
  
  #define MAX_TFTP_PATH_LEN 127

  const char *pxe_default_paths[] = {

  #ifdef CONFIG_SYS_SOC

  	"default-" CONFIG_SYS_ARCH "-" CONFIG_SYS_SOC,

  #endif

  	"default-" CONFIG_SYS_ARCH,
  	"default",
  	NULL
  };

  static bool is_pxe;

  /*
   * Like getenv, but prints an error if envvar isn't defined in the
   * environment.  It always returns what getenv does, so it can be used in
   * place of getenv without changing error handling otherwise.
   */

  static char *from_env(const char *envvar)

  {
  	char *ret;
  
  	ret = getenv(envvar);
  
  	if (!ret)
  		printf("missing environment variable: %s
  ", envvar);
  
  	return ret;
  }
  
  /*
   * Convert an ethaddr from the environment to the format used by pxelinux
   * filenames based on mac addresses. Convert's ':' to '-', and adds "01-" to
   * the beginning of the ethernet address to indicate a hardware type of
   * Ethernet. Also converts uppercase hex characters into lowercase, to match
   * pxelinux's behavior.
   *
   * Returns 1 for success, -ENOENT if 'ethaddr' is undefined in the
   * environment, or some other value < 0 on error.
   */
  static int format_mac_pxe(char *outbuf, size_t outbuf_len)
  {

  	uchar ethaddr[6];

  	if (outbuf_len < 21) {

  		printf("outbuf is too small (%zd < 21)
  ", outbuf_len);

  
  		return -EINVAL;
  	}

  	if (!eth_getenv_enetaddr_by_index("eth", eth_get_dev_index(),
  					  ethaddr))
  		return -ENOENT;

  	sprintf(outbuf, "01-%02x-%02x-%02x-%02x-%02x-%02x",
  		ethaddr[0], ethaddr[1], ethaddr[2],
  		ethaddr[3], ethaddr[4], ethaddr[5]);

  
  	return 1;
  }
  
  /*
   * Returns the directory the file specified in the bootfile env variable is
   * in. If bootfile isn't defined in the environment, return NULL, which should
   * be interpreted as "don't prepend anything to paths".
   */

  static int get_bootfile_path(const char *file_path, char *bootfile_path,
  			     size_t bootfile_path_size)

  {
  	char *bootfile, *last_slash;

  	size_t path_len = 0;

  	/* Only syslinux allows absolute paths */
  	if (file_path[0] == '/' && !is_pxe)

  		goto ret;

  
  	bootfile = from_env("bootfile");

  	if (!bootfile)
  		goto ret;

  
  	last_slash = strrchr(bootfile, '/');

  	if (last_slash == NULL)
  		goto ret;

  
  	path_len = (last_slash - bootfile) + 1;
  
  	if (bootfile_path_size < path_len) {

  		printf("bootfile_path too small. (%zd < %zd)
  ",

  				bootfile_path_size, path_len);
  
  		return -1;
  	}
  
  	strncpy(bootfile_path, bootfile, path_len);

   ret:

  	bootfile_path[path_len] = '\0';
  
  	return 1;
  }

  static int (*do_getfile)(cmd_tbl_t *cmdtp, const char *file_path, char *file_addr);

  static int do_get_tftp(cmd_tbl_t *cmdtp, const char *file_path, char *file_addr)

  {
  	char *tftp_argv[] = {"tftp", NULL, NULL, NULL};
  
  	tftp_argv[1] = file_addr;

  	tftp_argv[2] = (void *)file_path;

  	if (do_tftpb(cmdtp, 0, 3, tftp_argv))

  		return -ENOENT;
  
  	return 1;
  }
  
  static char *fs_argv[5];

  static int do_get_ext2(cmd_tbl_t *cmdtp, const char *file_path, char *file_addr)

  {
  #ifdef CONFIG_CMD_EXT2
  	fs_argv[0] = "ext2load";
  	fs_argv[3] = file_addr;

  	fs_argv[4] = (void *)file_path;

  	if (!do_ext2load(cmdtp, 0, 5, fs_argv))

  		return 1;
  #endif
  	return -ENOENT;
  }

  static int do_get_fat(cmd_tbl_t *cmdtp, const char *file_path, char *file_addr)

  {
  #ifdef CONFIG_CMD_FAT
  	fs_argv[0] = "fatload";
  	fs_argv[3] = file_addr;

  	fs_argv[4] = (void *)file_path;

  	if (!do_fat_fsload(cmdtp, 0, 5, fs_argv))

  		return 1;
  #endif
  	return -ENOENT;
  }

  static int do_get_any(cmd_tbl_t *cmdtp, const char *file_path, char *file_addr)
  {
  #ifdef CONFIG_CMD_FS_GENERIC
  	fs_argv[0] = "load";
  	fs_argv[3] = file_addr;
  	fs_argv[4] = (void *)file_path;
  
  	if (!do_load(cmdtp, 0, 5, fs_argv, FS_TYPE_ANY))
  		return 1;
  #endif
  	return -ENOENT;
  }

  /*
   * As in pxelinux, paths to files referenced from files we retrieve are
   * relative to the location of bootfile. get_relfile takes such a path and
   * joins it with the bootfile path to get the full path to the target file. If
   * the bootfile path is NULL, we use file_path as is.
   *
   * Returns 1 for success, or < 0 on error.
   */

  static int get_relfile(cmd_tbl_t *cmdtp, const char *file_path, void *file_addr)

  {
  	size_t path_len;
  	char relfile[MAX_TFTP_PATH_LEN+1];
  	char addr_buf[10];

  	int err;

  	err = get_bootfile_path(file_path, relfile, sizeof(relfile));

  
  	if (err < 0)
  		return err;
  
  	path_len = strlen(file_path);
  	path_len += strlen(relfile);
  
  	if (path_len > MAX_TFTP_PATH_LEN) {
  		printf("Base path too long (%s%s)
  ",
  					relfile,
  					file_path);
  
  		return -ENAMETOOLONG;
  	}
  
  	strcat(relfile, file_path);
  
  	printf("Retrieving file: %s
  ", relfile);
  
  	sprintf(addr_buf, "%p", file_addr);

  	return do_getfile(cmdtp, relfile, addr_buf);

  }
  
  /*
   * Retrieve the file at 'file_path' to the locate given by 'file_addr'. If
   * 'bootfile' was specified in the environment, the path to bootfile will be
   * prepended to 'file_path' and the resulting path will be used.
   *
   * Returns 1 on success, or < 0 for error.
   */

  static int get_pxe_file(cmd_tbl_t *cmdtp, const char *file_path, void *file_addr)

  {
  	unsigned long config_file_size;
  	char *tftp_filesize;
  	int err;

  	err = get_relfile(cmdtp, file_path, file_addr);

  
  	if (err < 0)
  		return err;
  
  	/*
  	 * the file comes without a NUL byte at the end, so find out its size
  	 * and add the NUL byte.
  	 */
  	tftp_filesize = from_env("filesize");
  
  	if (!tftp_filesize)
  		return -ENOENT;
  
  	if (strict_strtoul(tftp_filesize, 16, &config_file_size) < 0)
  		return -EINVAL;
  
  	*(char *)(file_addr + config_file_size) = '\0';
  
  	return 1;
  }
  
  #define PXELINUX_DIR "pxelinux.cfg/"
  
  /*
   * Retrieves a file in the 'pxelinux.cfg' folder. Since this uses get_pxe_file
   * to do the hard work, the location of the 'pxelinux.cfg' folder is generated
   * from the bootfile path, as described above.
   *
   * Returns 1 on success or < 0 on error.
   */

  static int get_pxelinux_path(cmd_tbl_t *cmdtp, const char *file, void *pxefile_addr_r)

  {
  	size_t base_len = strlen(PXELINUX_DIR);
  	char path[MAX_TFTP_PATH_LEN+1];
  
  	if (base_len + strlen(file) > MAX_TFTP_PATH_LEN) {
  		printf("path (%s%s) too long, skipping
  ",
  				PXELINUX_DIR, file);
  		return -ENAMETOOLONG;
  	}
  
  	sprintf(path, PXELINUX_DIR "%s", file);

  	return get_pxe_file(cmdtp, path, pxefile_addr_r);

  }
  
  /*
   * Looks for a pxe file with a name based on the pxeuuid environment variable.
   *
   * Returns 1 on success or < 0 on error.
   */

  static int pxe_uuid_path(cmd_tbl_t *cmdtp, void *pxefile_addr_r)

  {
  	char *uuid_str;
  
  	uuid_str = from_env("pxeuuid");
  
  	if (!uuid_str)
  		return -ENOENT;

  	return get_pxelinux_path(cmdtp, uuid_str, pxefile_addr_r);

  }
  
  /*
   * Looks for a pxe file with a name based on the 'ethaddr' environment
   * variable.
   *
   * Returns 1 on success or < 0 on error.
   */

  static int pxe_mac_path(cmd_tbl_t *cmdtp, void *pxefile_addr_r)

  {
  	char mac_str[21];
  	int err;
  
  	err = format_mac_pxe(mac_str, sizeof(mac_str));
  
  	if (err < 0)
  		return err;

  	return get_pxelinux_path(cmdtp, mac_str, pxefile_addr_r);

  }
  
  /*
   * Looks for pxe files with names based on our IP address. See pxelinux
   * documentation for details on what these file names look like.  We match
   * that exactly.
   *
   * Returns 1 on success or < 0 on error.
   */

  static int pxe_ipaddr_paths(cmd_tbl_t *cmdtp, void *pxefile_addr_r)

  {
  	char ip_addr[9];
  	int mask_pos, err;
  
  	sprintf(ip_addr, "%08X", ntohl(NetOurIP));
  
  	for (mask_pos = 7; mask_pos >= 0;  mask_pos--) {

  		err = get_pxelinux_path(cmdtp, ip_addr, pxefile_addr_r);

  
  		if (err > 0)
  			return err;
  
  		ip_addr[mask_pos] = '\0';
  	}
  
  	return -ENOENT;
  }
  
  /*
   * Entry point for the 'pxe get' command.
   * This Follows pxelinux's rules to download a config file from a tftp server.
   * The file is stored at the location given by the pxefile_addr_r environment
   * variable, which must be set.
   *
   * UUID comes from pxeuuid env variable, if defined
   * MAC addr comes from ethaddr env variable, if defined
   * IP
   *
   * see http://syslinux.zytor.com/wiki/index.php/PXELINUX
   *
   * Returns 0 on success or 1 on error.
   */
  static int
  do_pxe_get(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	char *pxefile_addr_str;

  	unsigned long pxefile_addr_r;

  	int err, i = 0;

  	do_getfile = do_get_tftp;

  	if (argc != 1)

  		return CMD_RET_USAGE;

  	pxefile_addr_str = from_env("pxefile_addr_r");
  
  	if (!pxefile_addr_str)
  		return 1;
  
  	err = strict_strtoul(pxefile_addr_str, 16,
  				(unsigned long *)&pxefile_addr_r);
  	if (err < 0)
  		return 1;
  
  	/*
  	 * Keep trying paths until we successfully get a file we're looking
  	 * for.
  	 */

  	if (pxe_uuid_path(cmdtp, (void *)pxefile_addr_r) > 0 ||
  	    pxe_mac_path(cmdtp, (void *)pxefile_addr_r) > 0 ||
  	    pxe_ipaddr_paths(cmdtp, (void *)pxefile_addr_r) > 0) {

  		printf("Config file found
  ");
  
  		return 0;
  	}

  	while (pxe_default_paths[i]) {

  		if (get_pxelinux_path(cmdtp, pxe_default_paths[i],

  				      (void *)pxefile_addr_r) > 0) {
  			printf("Config file found
  ");
  			return 0;
  		}
  		i++;
  	}

  	printf("Config file not found
  ");
  
  	return 1;
  }
  
  /*
   * Wrapper to make it easier to store the file at file_path in the location
   * specified by envaddr_name. file_path will be joined to the bootfile path,
   * if any is specified.
   *
   * Returns 1 on success or < 0 on error.
   */

  static int get_relfile_envaddr(cmd_tbl_t *cmdtp, const char *file_path, const char *envaddr_name)

  {

  	unsigned long file_addr;

  	char *envaddr;
  
  	envaddr = from_env(envaddr_name);
  
  	if (!envaddr)
  		return -ENOENT;

  	if (strict_strtoul(envaddr, 16, &file_addr) < 0)

  		return -EINVAL;

  	return get_relfile(cmdtp, file_path, (void *)file_addr);

  }
  
  /*
   * A note on the pxe file parser.
   *
   * We're parsing files that use syslinux grammar, which has a few quirks.
   * String literals must be recognized based on context - there is no
   * quoting or escaping support. There's also nothing to explicitly indicate
   * when a label section completes. We deal with that by ending a label
   * section whenever we see a line that doesn't include.
   *
   * As with the syslinux family, this same file format could be reused in the
   * future for non pxe purposes. The only action it takes during parsing that
   * would throw this off is handling of include files. It assumes we're using
   * pxe, and does a tftp download of a file listed as an include file in the
   * middle of the parsing operation. That could be handled by refactoring it to
   * take a 'include file getter' function.
   */
  
  /*
   * Describes a single label given in a pxe file.
   *
   * Create these with the 'label_create' function given below.
   *
   * name - the name of the menu as given on the 'menu label' line.
   * kernel - the path to the kernel file to use for this label.
   * append - kernel command line to use when booting this label
   * initrd - path to the initrd to use for this label.
   * attempted - 0 if we haven't tried to boot this label, 1 if we have.
   * localboot - 1 if this label specified 'localboot', 0 otherwise.
   * list - lets these form a list, which a pxe_menu struct will hold.
   */
  struct pxe_label {

  	char num[4];

  	char *name;

  	char *menu;

  	char *kernel;
  	char *append;
  	char *initrd;

  	char *fdt;

  	char *fdtdir;

  	int ipappend;

  	int attempted;
  	int localboot;

  	int localboot_val;

  	struct list_head list;
  };
  
  /*
   * Describes a pxe menu as given via pxe files.
   *
   * title - the name of the menu as given by a 'menu title' line.
   * default_label - the name of the default label, if any.
   * timeout - time in tenths of a second to wait for a user key-press before
   *           booting the default label.
   * prompt - if 0, don't prompt for a choice unless the timeout period is
   *          interrupted.  If 1, always prompt for a choice regardless of
   *          timeout.
   * labels - a list of labels defined for the menu.
   */
  struct pxe_menu {
  	char *title;
  	char *default_label;
  	int timeout;
  	int prompt;
  	struct list_head labels;
  };
  
  /*
   * Allocates memory for and initializes a pxe_label. This uses malloc, so the
   * result must be free()'d to reclaim the memory.
   *
   * Returns NULL if malloc fails.
   */
  static struct pxe_label *label_create(void)
  {
  	struct pxe_label *label;
  
  	label = malloc(sizeof(struct pxe_label));
  
  	if (!label)
  		return NULL;
  
  	memset(label, 0, sizeof(struct pxe_label));
  
  	return label;
  }
  
  /*
   * Free the memory used by a pxe_label, including that used by its name,
   * kernel, append and initrd members, if they're non NULL.
   *
   * So - be sure to only use dynamically allocated memory for the members of
   * the pxe_label struct, unless you want to clean it up first. These are
   * currently only created by the pxe file parsing code.
   */
  static void label_destroy(struct pxe_label *label)
  {
  	if (label->name)
  		free(label->name);
  
  	if (label->kernel)
  		free(label->kernel);
  
  	if (label->append)
  		free(label->append);
  
  	if (label->initrd)
  		free(label->initrd);

  	if (label->fdt)
  		free(label->fdt);

  	if (label->fdtdir)
  		free(label->fdtdir);

  	free(label);
  }
  
  /*
   * Print a label and its string members if they're defined.
   *
   * This is passed as a callback to the menu code for displaying each
   * menu entry.
   */
  static void label_print(void *data)
  {
  	struct pxe_label *label = data;

  	const char *c = label->menu ? label->menu : label->name;

  	printf("%s:\t%s
  ", label->num, c);

  }
  
  /*
   * Boot a label that specified 'localboot'. This requires that the 'localcmd'
   * environment variable is defined. Its contents will be executed as U-boot
   * command.  If the label specified an 'append' line, its contents will be
   * used to overwrite the contents of the 'bootargs' environment variable prior
   * to running 'localcmd'.
   *
   * Returns 1 on success or < 0 on error.
   */
  static int label_localboot(struct pxe_label *label)
  {

  	char *localcmd;

  
  	localcmd = from_env("localcmd");
  
  	if (!localcmd)
  		return -ENOENT;

  	if (label->append)
  		setenv("bootargs", label->append);

  	debug("running: %s
  ", localcmd);

  	return run_command_list(localcmd, strlen(localcmd), 0);

  }
  
  /*
   * Boot according to the contents of a pxe_label.
   *
   * If we can't boot for any reason, we return.  A successful boot never
   * returns.
   *
   * The kernel will be stored in the location given by the 'kernel_addr_r'
   * environment variable.
   *
   * If the label specifies an initrd file, it will be stored in the location
   * given by the 'ramdisk_addr_r' environment variable.
   *
   * If the label specifies an 'append' line, its contents will overwrite that
   * of the 'bootargs' environment variable.
   */

  static int label_boot(cmd_tbl_t *cmdtp, struct pxe_label *label)

  {
  	char *bootm_argv[] = { "bootm", NULL, NULL, NULL, NULL };

  	char initrd_str[22];

  	char mac_str[29] = "";
  	char ip_str[68] = "";
  	char *bootargs;

  	int bootm_argc = 3;

  	int len = 0;

  
  	label_print(label);
  
  	label->attempted = 1;
  
  	if (label->localboot) {

  		if (label->localboot_val >= 0)
  			label_localboot(label);
  		return 0;

  	}
  
  	if (label->kernel == NULL) {
  		printf("No kernel given, skipping %s
  ",
  				label->name);

  		return 1;

  	}
  
  	if (label->initrd) {

  		if (get_relfile_envaddr(cmdtp, label->initrd, "ramdisk_addr_r") < 0) {

  			printf("Skipping %s for failure retrieving initrd
  ",
  					label->name);

  			return 1;

  		}

  		bootm_argv[2] = initrd_str;
  		strcpy(bootm_argv[2], getenv("ramdisk_addr_r"));
  		strcat(bootm_argv[2], ":");
  		strcat(bootm_argv[2], getenv("filesize"));

  	} else {
  		bootm_argv[2] = "-";
  	}

  	if (get_relfile_envaddr(cmdtp, label->kernel, "kernel_addr_r") < 0) {

  		printf("Skipping %s for failure retrieving kernel
  ",
  				label->name);

  		return 1;

  	}

  	if (label->ipappend & 0x1) {
  		sprintf(ip_str, " ip=%s:%s:%s:%s",
  			getenv("ipaddr"), getenv("serverip"),
  			getenv("gatewayip"), getenv("netmask"));
  		len += strlen(ip_str);
  	}
  
  	if (label->ipappend & 0x2) {
  		int err;
  		strcpy(mac_str, " BOOTIF=");
  		err = format_mac_pxe(mac_str + 8, sizeof(mac_str) - 8);
  		if (err < 0)
  			mac_str[0] = '\0';
  		len += strlen(mac_str);
  	}
  
  	if (label->append)
  		len += strlen(label->append);
  
  	if (len) {
  		bootargs = malloc(len + 1);
  		if (!bootargs)
  			return 1;
  		bootargs[0] = '\0';
  		if (label->append)
  			strcpy(bootargs, label->append);
  		strcat(bootargs, ip_str);
  		strcat(bootargs, mac_str);
  
  		setenv("bootargs", bootargs);
  		printf("append: %s
  ", bootargs);
  
  		free(bootargs);

  	}

  
  	bootm_argv[1] = getenv("kernel_addr_r");
  
  	/*

  	 * fdt usage is optional:
  	 * It handles the following scenarios. All scenarios are exclusive
  	 *
  	 * Scenario 1: If fdt_addr_r specified and "fdt" label is defined in
  	 * pxe file, retrieve fdt blob from server. Pass fdt_addr_r to bootm,
  	 * and adjust argc appropriately.
  	 *
  	 * Scenario 2: If there is an fdt_addr specified, pass it along to
  	 * bootm, and adjust argc appropriately.
  	 *
  	 * Scenario 3: fdt blob is not available.

  	 */

  	bootm_argv[3] = getenv("fdt_addr_r");
  
  	/* if fdt label is defined then get fdt from server */

  	if (bootm_argv[3]) {
  		char *fdtfile = NULL;
  		char *fdtfilefree = NULL;
  
  		if (label->fdt) {
  			fdtfile = label->fdt;
  		} else if (label->fdtdir) {

  			char *f1, *f2, *f3, *f4, *slash;
  
  			f1 = getenv("fdtfile");
  			if (f1) {
  				f2 = "";
  				f3 = "";
  				f4 = "";
  			} else {
  				/*
  				 * For complex cases where this code doesn't
  				 * generate the correct filename, the board
  				 * code should set $fdtfile during early boot,
  				 * or the boot scripts should set $fdtfile
  				 * before invoking "pxe" or "sysboot".
  				 */
  				f1 = getenv("soc");
  				f2 = "-";
  				f3 = getenv("board");
  				f4 = ".dtb";

  			}

  
  			len = strlen(label->fdtdir);
  			if (!len)
  				slash = "./";
  			else if (label->fdtdir[len - 1] != '/')
  				slash = "/";
  			else
  				slash = "";
  
  			len = strlen(label->fdtdir) + strlen(slash) +
  				strlen(f1) + strlen(f2) + strlen(f3) +
  				strlen(f4) + 1;
  			fdtfilefree = malloc(len);
  			if (!fdtfilefree) {
  				printf("malloc fail (FDT filename)
  ");
  				return 1;
  			}
  
  			snprintf(fdtfilefree, len, "%s%s%s%s%s%s",
  				 label->fdtdir, slash, f1, f2, f3, f4);
  			fdtfile = fdtfilefree;

  		}

  
  		if (fdtfile) {
  			int err = get_relfile_envaddr(cmdtp, fdtfile, "fdt_addr_r");
  			free(fdtfilefree);
  			if (err < 0) {
  				printf("Skipping %s for failure retrieving fdt
  ",
  						label->name);
  				return 1;
  			}
  		} else {
  			bootm_argv[3] = NULL;
  		}
  	}
  
  	if (!bootm_argv[3])

  		bootm_argv[3] = getenv("fdt_addr");

  
  	if (bootm_argv[3])
  		bootm_argc = 4;

  	do_bootm(cmdtp, 0, bootm_argc, bootm_argv);

  
  #ifdef CONFIG_CMD_BOOTZ
  	/* Try booting a zImage if do_bootm returns */

  	do_bootz(cmdtp, 0, bootm_argc, bootm_argv);

  #endif

  	return 1;

  }
  
  /*
   * Tokens for the pxe file parser.
   */
  enum token_type {
  	T_EOL,
  	T_STRING,
  	T_EOF,
  	T_MENU,
  	T_TITLE,
  	T_TIMEOUT,
  	T_LABEL,
  	T_KERNEL,

  	T_LINUX,

  	T_APPEND,
  	T_INITRD,
  	T_LOCALBOOT,
  	T_DEFAULT,
  	T_PROMPT,
  	T_INCLUDE,

  	T_FDT,

  	T_FDTDIR,

  	T_ONTIMEOUT,

  	T_IPAPPEND,

  	T_INVALID
  };
  
  /*
   * A token - given by a value and a type.
   */
  struct token {
  	char *val;
  	enum token_type type;
  };
  
  /*
   * Keywords recognized.
   */
  static const struct token keywords[] = {
  	{"menu", T_MENU},
  	{"title", T_TITLE},
  	{"timeout", T_TIMEOUT},
  	{"default", T_DEFAULT},
  	{"prompt", T_PROMPT},
  	{"label", T_LABEL},
  	{"kernel", T_KERNEL},

  	{"linux", T_LINUX},

  	{"localboot", T_LOCALBOOT},
  	{"append", T_APPEND},
  	{"initrd", T_INITRD},
  	{"include", T_INCLUDE},

  	{"devicetree", T_FDT},

  	{"fdt", T_FDT},

  	{"devicetreedir", T_FDTDIR},
  	{"fdtdir", T_FDTDIR},

  	{"ontimeout", T_ONTIMEOUT,},

  	{"ipappend", T_IPAPPEND,},

  	{NULL, T_INVALID}
  };
  
  /*
   * Since pxe(linux) files don't have a token to identify the start of a
   * literal, we have to keep track of when we're in a state where a literal is
   * expected vs when we're in a state a keyword is expected.
   */
  enum lex_state {
  	L_NORMAL = 0,
  	L_KEYWORD,
  	L_SLITERAL
  };
  
  /*
   * get_string retrieves a string from *p and stores it as a token in
   * *t.
   *
   * get_string used for scanning both string literals and keywords.
   *
   * Characters from *p are copied into t-val until a character equal to
   * delim is found, or a NUL byte is reached. If delim has the special value of
   * ' ', any whitespace character will be used as a delimiter.
   *
   * If lower is unequal to 0, uppercase characters will be converted to
   * lowercase in the result. This is useful to make keywords case
   * insensitive.
   *
   * The location of *p is updated to point to the first character after the end
   * of the token - the ending delimiter.
   *
   * On success, the new value of t->val is returned. Memory for t->val is
   * allocated using malloc and must be free()'d to reclaim it.  If insufficient
   * memory is available, NULL is returned.
   */
  static char *get_string(char **p, struct token *t, char delim, int lower)
  {
  	char *b, *e;
  	size_t len, i;
  
  	/*
  	 * b and e both start at the beginning of the input stream.
  	 *
  	 * e is incremented until we find the ending delimiter, or a NUL byte
  	 * is reached. Then, we take e - b to find the length of the token.
  	 */
  	b = e = *p;
  
  	while (*e) {
  		if ((delim == ' ' && isspace(*e)) || delim == *e)
  			break;
  		e++;
  	}
  
  	len = e - b;
  
  	/*
  	 * Allocate memory to hold the string, and copy it in, converting
  	 * characters to lowercase if lower is != 0.
  	 */
  	t->val = malloc(len + 1);
  	if (!t->val)
  		return NULL;
  
  	for (i = 0; i < len; i++, b++) {
  		if (lower)
  			t->val[i] = tolower(*b);
  		else
  			t->val[i] = *b;
  	}
  
  	t->val[len] = '\0';
  
  	/*
  	 * Update *p so the caller knows where to continue scanning.
  	 */
  	*p = e;
  
  	t->type = T_STRING;
  
  	return t->val;
  }
  
  /*
   * Populate a keyword token with a type and value.
   */
  static void get_keyword(struct token *t)
  {
  	int i;
  
  	for (i = 0; keywords[i].val; i++) {
  		if (!strcmp(t->val, keywords[i].val)) {
  			t->type = keywords[i].type;
  			break;
  		}
  	}
  }
  
  /*
   * Get the next token.  We have to keep track of which state we're in to know
   * if we're looking to get a string literal or a keyword.
   *
   * *p is updated to point at the first character after the current token.
   */
  static void get_token(char **p, struct token *t, enum lex_state state)
  {
  	char *c = *p;
  
  	t->type = T_INVALID;
  
  	/* eat non EOL whitespace */
  	while (isblank(*c))
  		c++;
  
  	/*
  	 * eat comments. note that string literals can't begin with #, but
  	 * can contain a # after their first character.
  	 */
  	if (*c == '#') {
  		while (*c && *c != '
  ')
  			c++;
  	}
  
  	if (*c == '
  ') {
  		t->type = T_EOL;
  		c++;
  	} else if (*c == '\0') {
  		t->type = T_EOF;
  		c++;
  	} else if (state == L_SLITERAL) {
  		get_string(&c, t, '
  ', 0);
  	} else if (state == L_KEYWORD) {
  		/*
  		 * when we expect a keyword, we first get the next string
  		 * token delimited by whitespace, and then check if it
  		 * matches a keyword in our keyword list. if it does, it's
  		 * converted to a keyword token of the appropriate type, and
  		 * if not, it remains a string token.
  		 */
  		get_string(&c, t, ' ', 1);
  		get_keyword(t);
  	}
  
  	*p = c;
  }
  
  /*
   * Increment *c until we get to the end of the current line, or EOF.
   */
  static void eol_or_eof(char **c)
  {
  	while (**c && **c != '
  ')
  		(*c)++;
  }
  
  /*
   * All of these parse_* functions share some common behavior.
   *
   * They finish with *c pointing after the token they parse, and return 1 on
   * success, or < 0 on error.
   */
  
  /*
   * Parse a string literal and store a pointer it at *dst. String literals
   * terminate at the end of the line.
   */
  static int parse_sliteral(char **c, char **dst)
  {
  	struct token t;
  	char *s = *c;
  
  	get_token(c, &t, L_SLITERAL);
  
  	if (t.type != T_STRING) {
  		printf("Expected string literal: %.*s
  ", (int)(*c - s), s);
  		return -EINVAL;
  	}
  
  	*dst = t.val;
  
  	return 1;
  }
  
  /*
   * Parse a base 10 (unsigned) integer and store it at *dst.
   */
  static int parse_integer(char **c, int *dst)
  {
  	struct token t;
  	char *s = *c;

  
  	get_token(c, &t, L_SLITERAL);
  
  	if (t.type != T_STRING) {
  		printf("Expected string: %.*s
  ", (int)(*c - s), s);
  		return -EINVAL;
  	}

  	*dst = simple_strtol(t.val, NULL, 10);

  
  	free(t.val);
  
  	return 1;
  }

  static int parse_pxefile_top(cmd_tbl_t *cmdtp, char *p, struct pxe_menu *cfg, int nest_level);

  
  /*
   * Parse an include statement, and retrieve and parse the file it mentions.
   *
   * base should point to a location where it's safe to store the file, and
   * nest_level should indicate how many nested includes have occurred. For this
   * include, nest_level has already been incremented and doesn't need to be
   * incremented here.
   */

  static int handle_include(cmd_tbl_t *cmdtp, char **c, char *base,

  				struct pxe_menu *cfg, int nest_level)
  {
  	char *include_path;
  	char *s = *c;
  	int err;
  
  	err = parse_sliteral(c, &include_path);
  
  	if (err < 0) {
  		printf("Expected include path: %.*s
  ",
  				 (int)(*c - s), s);
  		return err;
  	}

  	err = get_pxe_file(cmdtp, include_path, base);

  
  	if (err < 0) {
  		printf("Couldn't retrieve %s
  ", include_path);
  		return err;
  	}

  	return parse_pxefile_top(cmdtp, base, cfg, nest_level);

  }
  
  /*
   * Parse lines that begin with 'menu'.
   *
   * b and nest are provided to handle the 'menu include' case.
   *
   * b should be the address where the file currently being parsed is stored.
   *
   * nest_level should be 1 when parsing the top level pxe file, 2 when parsing
   * a file it includes, 3 when parsing a file included by that file, and so on.
   */

  static int parse_menu(cmd_tbl_t *cmdtp, char **c, struct pxe_menu *cfg, char *b, int nest_level)

  {
  	struct token t;
  	char *s = *c;

  	int err = 0;

  
  	get_token(c, &t, L_KEYWORD);
  
  	switch (t.type) {
  	case T_TITLE:
  		err = parse_sliteral(c, &cfg->title);
  
  		break;
  
  	case T_INCLUDE:

  		err = handle_include(cmdtp, c, b + strlen(b) + 1, cfg,

  						nest_level + 1);
  		break;
  
  	default:
  		printf("Ignoring malformed menu command: %.*s
  ",
  				(int)(*c - s), s);
  	}
  
  	if (err < 0)
  		return err;
  
  	eol_or_eof(c);
  
  	return 1;
  }
  
  /*
   * Handles parsing a 'menu line' when we're parsing a label.
   */
  static int parse_label_menu(char **c, struct pxe_menu *cfg,
  				struct pxe_label *label)
  {
  	struct token t;
  	char *s;
  
  	s = *c;
  
  	get_token(c, &t, L_KEYWORD);
  
  	switch (t.type) {
  	case T_DEFAULT:

  		if (!cfg->default_label)
  			cfg->default_label = strdup(label->name);

  
  		if (!cfg->default_label)
  			return -ENOMEM;
  
  		break;

  	case T_LABEL:
  		parse_sliteral(c, &label->menu);
  		break;

  	default:
  		printf("Ignoring malformed menu command: %.*s
  ",
  				(int)(*c - s), s);
  	}
  
  	eol_or_eof(c);
  
  	return 0;
  }
  
  /*
   * Parses a label and adds it to the list of labels for a menu.
   *
   * A label ends when we either get to the end of a file, or
   * get some input we otherwise don't have a handler defined
   * for.
   *
   */
  static int parse_label(char **c, struct pxe_menu *cfg)
  {
  	struct token t;

  	int len;

  	char *s = *c;
  	struct pxe_label *label;
  	int err;
  
  	label = label_create();
  	if (!label)
  		return -ENOMEM;
  
  	err = parse_sliteral(c, &label->name);
  	if (err < 0) {
  		printf("Expected label name: %.*s
  ", (int)(*c - s), s);
  		label_destroy(label);
  		return -EINVAL;
  	}
  
  	list_add_tail(&label->list, &cfg->labels);
  
  	while (1) {
  		s = *c;
  		get_token(c, &t, L_KEYWORD);
  
  		err = 0;
  		switch (t.type) {
  		case T_MENU:
  			err = parse_label_menu(c, cfg, label);
  			break;
  
  		case T_KERNEL:

  		case T_LINUX:

  			err = parse_sliteral(c, &label->kernel);
  			break;
  
  		case T_APPEND:
  			err = parse_sliteral(c, &label->append);

  			if (label->initrd)
  				break;
  			s = strstr(label->append, "initrd=");
  			if (!s)
  				break;
  			s += 7;
  			len = (int)(strchr(s, ' ') - s);
  			label->initrd = malloc(len + 1);
  			strncpy(label->initrd, s, len);
  			label->initrd[len] = '\0';

  			break;
  
  		case T_INITRD:

  			if (!label->initrd)
  				err = parse_sliteral(c, &label->initrd);

  			break;

  		case T_FDT:
  			if (!label->fdt)
  				err = parse_sliteral(c, &label->fdt);
  			break;

  		case T_FDTDIR:
  			if (!label->fdtdir)
  				err = parse_sliteral(c, &label->fdtdir);
  			break;

  		case T_LOCALBOOT:

  			label->localboot = 1;
  			err = parse_integer(c, &label->localboot_val);

  			break;

  		case T_IPAPPEND:
  			err = parse_integer(c, &label->ipappend);
  			break;

  		case T_EOL:
  			break;
  
  		default:
  			/*
  			 * put the token back! we don't want it - it's the end
  			 * of a label and whatever token this is, it's
  			 * something for the menu level context to handle.
  			 */
  			*c = s;
  			return 1;
  		}
  
  		if (err < 0)
  			return err;
  	}
  }
  
  /*
   * This 16 comes from the limit pxelinux imposes on nested includes.
   *
   * There is no reason at all we couldn't do more, but some limit helps prevent
   * infinite (until crash occurs) recursion if a file tries to include itself.
   */
  #define MAX_NEST_LEVEL 16
  
  /*
   * Entry point for parsing a menu file. nest_level indicates how many times
   * we've nested in includes.  It will be 1 for the top level menu file.
   *
   * Returns 1 on success, < 0 on error.
   */

  static int parse_pxefile_top(cmd_tbl_t *cmdtp, char *p, struct pxe_menu *cfg, int nest_level)

  {
  	struct token t;
  	char *s, *b, *label_name;
  	int err;
  
  	b = p;
  
  	if (nest_level > MAX_NEST_LEVEL) {
  		printf("Maximum nesting (%d) exceeded
  ", MAX_NEST_LEVEL);
  		return -EMLINK;
  	}
  
  	while (1) {
  		s = p;
  
  		get_token(&p, &t, L_KEYWORD);
  
  		err = 0;
  		switch (t.type) {
  		case T_MENU:

  			cfg->prompt = 1;

  			err = parse_menu(cmdtp, &p, cfg, b, nest_level);

  			break;
  
  		case T_TIMEOUT:
  			err = parse_integer(&p, &cfg->timeout);
  			break;
  
  		case T_LABEL:
  			err = parse_label(&p, cfg);
  			break;
  
  		case T_DEFAULT:

  		case T_ONTIMEOUT:

  			err = parse_sliteral(&p, &label_name);
  
  			if (label_name) {
  				if (cfg->default_label)
  					free(cfg->default_label);
  
  				cfg->default_label = label_name;
  			}
  
  			break;

  		case T_INCLUDE:

  			err = handle_include(cmdtp, &p, b + ALIGN(strlen(b), 4), cfg,

  							nest_level + 1);
  			break;

  		case T_PROMPT:

  			eol_or_eof(&p);

  			break;
  
  		case T_EOL:
  			break;
  
  		case T_EOF:
  			return 1;
  
  		default:
  			printf("Ignoring unknown command: %.*s
  ",
  							(int)(p - s), s);
  			eol_or_eof(&p);
  		}
  
  		if (err < 0)
  			return err;
  	}
  }
  
  /*
   * Free the memory used by a pxe_menu and its labels.
   */
  static void destroy_pxe_menu(struct pxe_menu *cfg)
  {
  	struct list_head *pos, *n;
  	struct pxe_label *label;
  
  	if (cfg->title)
  		free(cfg->title);
  
  	if (cfg->default_label)
  		free(cfg->default_label);
  
  	list_for_each_safe(pos, n, &cfg->labels) {
  		label = list_entry(pos, struct pxe_label, list);
  
  		label_destroy(label);
  	}
  
  	free(cfg);
  }
  
  /*
   * Entry point for parsing a pxe file. This is only used for the top level
   * file.
   *
   * Returns NULL if there is an error, otherwise, returns a pointer to a
   * pxe_menu struct populated with the results of parsing the pxe file (and any
   * files it includes). The resulting pxe_menu struct can be free()'d by using
   * the destroy_pxe_menu() function.
   */

  static struct pxe_menu *parse_pxefile(cmd_tbl_t *cmdtp, char *menucfg)

  {
  	struct pxe_menu *cfg;
  
  	cfg = malloc(sizeof(struct pxe_menu));
  
  	if (!cfg)
  		return NULL;
  
  	memset(cfg, 0, sizeof(struct pxe_menu));
  
  	INIT_LIST_HEAD(&cfg->labels);

  	if (parse_pxefile_top(cmdtp, menucfg, cfg, 1) < 0) {

  		destroy_pxe_menu(cfg);
  		return NULL;
  	}
  
  	return cfg;
  }
  
  /*
   * Converts a pxe_menu struct into a menu struct for use with U-boot's generic
   * menu code.
   */
  static struct menu *pxe_menu_to_menu(struct pxe_menu *cfg)
  {
  	struct pxe_label *label;
  	struct list_head *pos;
  	struct menu *m;
  	int err;

  	int i = 1;
  	char *default_num = NULL;

  
  	/*
  	 * Create a menu and add items for all the labels.
  	 */

  	m = menu_create(cfg->title, cfg->timeout, cfg->prompt, label_print,
  			NULL, NULL);

  
  	if (!m)
  		return NULL;
  
  	list_for_each(pos, &cfg->labels) {
  		label = list_entry(pos, struct pxe_label, list);

  		sprintf(label->num, "%d", i++);
  		if (menu_item_add(m, label->num, label) != 1) {

  			menu_destroy(m);
  			return NULL;
  		}

  		if (cfg->default_label &&

  		    (strcmp(label->name, cfg->default_label) == 0))

  			default_num = label->num;

  	}
  
  	/*
  	 * After we've created items for each label in the menu, set the
  	 * menu's default label if one was specified.
  	 */

  	if (default_num) {
  		err = menu_default_set(m, default_num);

  		if (err != 1) {
  			if (err != -ENOENT) {
  				menu_destroy(m);
  				return NULL;
  			}
  
  			printf("Missing default: %s
  ", cfg->default_label);
  		}
  	}
  
  	return m;
  }
  
  /*
   * Try to boot any labels we have yet to attempt to boot.
   */

  static void boot_unattempted_labels(cmd_tbl_t *cmdtp, struct pxe_menu *cfg)

  {
  	struct list_head *pos;
  	struct pxe_label *label;
  
  	list_for_each(pos, &cfg->labels) {
  		label = list_entry(pos, struct pxe_label, list);
  
  		if (!label->attempted)

  			label_boot(cmdtp, label);

  	}
  }
  
  /*
   * Boot the system as prescribed by a pxe_menu.
   *
   * Use the menu system to either get the user's choice or the default, based
   * on config or user input.  If there is no default or user's choice,
   * attempted to boot labels in the order they were given in pxe files.
   * If the default or user's choice fails to boot, attempt to boot other
   * labels in the order they were given in pxe files.
   *
   * If this function returns, there weren't any labels that successfully
   * booted, or the user interrupted the menu selection via ctrl+c.
   */

  static void handle_pxe_menu(cmd_tbl_t *cmdtp, struct pxe_menu *cfg)

  {
  	void *choice;
  	struct menu *m;
  	int err;
  
  	m = pxe_menu_to_menu(cfg);
  	if (!m)
  		return;
  
  	err = menu_get_choice(m, &choice);
  
  	menu_destroy(m);

  	/*
  	 * err == 1 means we got a choice back from menu_get_choice.
  	 *
  	 * err == -ENOENT if the menu was setup to select the default but no
  	 * default was set. in that case, we should continue trying to boot
  	 * labels that haven't been attempted yet.
  	 *
  	 * otherwise, the user interrupted or there was some other error and
  	 * we give up.
  	 */

  	if (err == 1) {

  		err = label_boot(cmdtp, choice);

  		if (!err)
  			return;
  	} else if (err != -ENOENT) {

  		return;

  	}

  	boot_unattempted_labels(cmdtp, cfg);

  }
  
  /*
   * Boots a system using a pxe file
   *
   * Returns 0 on success, 1 on error.
   */
  static int
  do_pxe_boot(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	unsigned long pxefile_addr_r;
  	struct pxe_menu *cfg;
  	char *pxefile_addr_str;

  	do_getfile = do_get_tftp;

  	if (argc == 1) {
  		pxefile_addr_str = from_env("pxefile_addr_r");
  		if (!pxefile_addr_str)
  			return 1;
  
  	} else if (argc == 2) {
  		pxefile_addr_str = argv[1];
  	} else {

  		return CMD_RET_USAGE;

  	}
  
  	if (strict_strtoul(pxefile_addr_str, 16, &pxefile_addr_r) < 0) {
  		printf("Invalid pxefile address: %s
  ", pxefile_addr_str);
  		return 1;
  	}

  	cfg = parse_pxefile(cmdtp, (char *)(pxefile_addr_r));

  
  	if (cfg == NULL) {
  		printf("Error parsing config file
  ");
  		return 1;
  	}

  	handle_pxe_menu(cmdtp, cfg);

  
  	destroy_pxe_menu(cfg);
  
  	return 0;
  }
  
  static cmd_tbl_t cmd_pxe_sub[] = {
  	U_BOOT_CMD_MKENT(get, 1, 1, do_pxe_get, "", ""),
  	U_BOOT_CMD_MKENT(boot, 2, 1, do_pxe_boot, "", "")
  };
  
  int do_pxe(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	cmd_tbl_t *cp;
  
  	if (argc < 2)

  		return CMD_RET_USAGE;

  	is_pxe = true;

  	/* drop initial "pxe" arg */
  	argc--;
  	argv++;
  
  	cp = find_cmd_tbl(argv[0], cmd_pxe_sub, ARRAY_SIZE(cmd_pxe_sub));
  
  	if (cp)
  		return cp->cmd(cmdtp, flag, argc, argv);

  	return CMD_RET_USAGE;

  }
  
  U_BOOT_CMD(
  	pxe, 3, 1, do_pxe,
  	"commands to get and boot from pxe files",
  	"get - try to retrieve a pxe file using tftp
  pxe "
  	"boot [pxefile_addr_r] - boot from the pxe file at pxefile_addr_r
  "
  );

  
  /*
   * Boots a system using a local disk syslinux/extlinux file
   *
   * Returns 0 on success, 1 on error.
   */
  int do_sysboot(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  {
  	unsigned long pxefile_addr_r;
  	struct pxe_menu *cfg;
  	char *pxefile_addr_str;
  	char *filename;
  	int prompt = 0;

  	is_pxe = false;

  	if (strstr(argv[1], "-p")) {
  		prompt = 1;
  		argc--;
  		argv++;
  	}
  
  	if (argc < 4)
  		return cmd_usage(cmdtp);
  
  	if (argc < 5) {
  		pxefile_addr_str = from_env("pxefile_addr_r");
  		if (!pxefile_addr_str)
  			return 1;
  	} else {
  		pxefile_addr_str = argv[4];
  	}
  
  	if (argc < 6)
  		filename = getenv("bootfile");
  	else {
  		filename = argv[5];
  		setenv("bootfile", filename);
  	}
  
  	if (strstr(argv[3], "ext2"))
  		do_getfile = do_get_ext2;
  	else if (strstr(argv[3], "fat"))
  		do_getfile = do_get_fat;

  	else if (strstr(argv[3], "any"))
  		do_getfile = do_get_any;

  	else {
  		printf("Invalid filesystem: %s
  ", argv[3]);
  		return 1;
  	}
  	fs_argv[1] = argv[1];
  	fs_argv[2] = argv[2];
  
  	if (strict_strtoul(pxefile_addr_str, 16, &pxefile_addr_r) < 0) {
  		printf("Invalid pxefile address: %s
  ", pxefile_addr_str);
  		return 1;
  	}

  	if (get_pxe_file(cmdtp, filename, (void *)pxefile_addr_r) < 0) {

  		printf("Error reading config file
  ");
  		return 1;
  	}

  	cfg = parse_pxefile(cmdtp, (char *)(pxefile_addr_r));

  
  	if (cfg == NULL) {
  		printf("Error parsing config file
  ");
  		return 1;
  	}
  
  	if (prompt)
  		cfg->prompt = 1;

  	handle_pxe_menu(cmdtp, cfg);

  
  	destroy_pxe_menu(cfg);
  
  	return 0;
  }
  
  U_BOOT_CMD(
  	sysboot, 7, 1, do_sysboot,
  	"command to get and boot from syslinux files",

  	"[-p] <interface> <dev[:part]> <ext2|fat|any> [addr] [filename]
  "
  	"    - load and parse syslinux menu file 'filename' from ext2, fat
  "
  	"      or any filesystem on 'dev' on 'interface' to address 'addr'"

  );