// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2010-2011 Calxeda, Inc.
 * Copyright (c) 2014, NVIDIA CORPORATION.  All rights reserved.
 */

#include <common.h>
#include <command.h>
#include <env.h>
#include <image.h>
#include <log.h>
#include <malloc.h>
#include <mapmem.h>
#include <lcd.h>
#include <net.h>
#include <fdt_support.h>
#include <linux/libfdt.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <errno.h>
#include <linux/list.h>

#include <splash.h>
#include <asm/io.h>

#include "menu.h"
#include "cli.h"

#include "pxe_utils.h"

#define MAX_TFTP_PATH_LEN 512

int pxe_get_file_size(ulong *sizep)
{
        const char *val;

        val = from_env("filesize");
        if (!val)
                return -ENOENT;

        if (strict_strtoul(val, 16, sizep) < 0)
                return -EINVAL;

        return 0;
}

/**
 * format_mac_pxe() - obtain a MAC address in the PXE format
 *
 * This produces a MAC-address string in the format for the current ethernet
 * device:
 *
 *   01-aa-bb-cc-dd-ee-ff
 *
 * where aa-ff is the MAC address in hex
 *
 * @outbuf: Buffer to write string to
 * @outbuf_len: length of buffer
 * @return 1 if OK, -ENOSPC if buffer is too small, -ENOENT is there is no
 *      current ethernet device
 */
int format_mac_pxe(char *outbuf, size_t outbuf_len)
{
        uchar ethaddr[6];

        if (outbuf_len < 21) {
                printf("outbuf is too small (%zd < 21)\n", outbuf_len);
                return -ENOSPC;
        }

        if (!eth_env_get_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;
}

/**
 * get_relfile() - read a file relative to the PXE file
 *
 * 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.
 *
 * @ctx: PXE context
 * @file_path: File path to read (relative to the PXE file)
 * @file_addr: Address to load file to
 * @filesizep: If not NULL, returns the file size in bytes
 * Returns 1 for success, or < 0 on error
 */
static int get_relfile(struct pxe_context *ctx, const char *file_path,
                       unsigned long file_addr, ulong *filesizep)
{
        size_t path_len;
        char relfile[MAX_TFTP_PATH_LEN + 1];
        char addr_buf[18];
        ulong size;
        int ret;

        if (file_path[0] == '/' && ctx->allow_abs_path)
                *relfile = '\0';
        else
                strncpy(relfile, ctx->bootdir, MAX_TFTP_PATH_LEN);

        path_len = strlen(file_path) + strlen(relfile);

        if (path_len > MAX_TFTP_PATH_LEN) {
                printf("Base path too long (%s%s)\n", relfile, file_path);

                return -ENAMETOOLONG;
        }

        strcat(relfile, file_path);

        printf("Retrieving file: %s\n", relfile);

        sprintf(addr_buf, "%lx", file_addr);

        ret = ctx->getfile(ctx, relfile, addr_buf, &size);
        if (ret < 0)
                return log_msg_ret("get", ret);
        if (filesizep)
                *filesizep = size;

        return 1;
}

/**
 * get_pxe_file() - read a file
 *
 * The file is read and nul-terminated
 *
 * @ctx: PXE context
 * @file_path: File path to read (relative to the PXE file)
 * @file_addr: Address to load file to
 * Returns 1 for success, or < 0 on error
 */
int get_pxe_file(struct pxe_context *ctx, const char *file_path,
                 ulong file_addr)
{
        ulong size;
        int err;
        char *buf;

        err = get_relfile(ctx, file_path, file_addr, &size);
        if (err < 0)
                return err;

        buf = map_sysmem(file_addr + size, 1);
        *buf = '\0';
        unmap_sysmem(buf);

        return 1;
}

#define PXELINUX_DIR "pxelinux.cfg/"

/**
 * get_pxelinux_path() - Get a file in the pxelinux.cfg/ directory
 *
 * @ctx: PXE context
 * @file: Filename to process (relative to pxelinux.cfg/)
 * Returns 1 for success, -ENAMETOOLONG if the resulting path is too long.
 *      or other value < 0 on other error
 */
int get_pxelinux_path(struct pxe_context *ctx, const char *file,
                      unsigned long 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\n",
                       PXELINUX_DIR, file);
                return -ENAMETOOLONG;
        }

        sprintf(path, PXELINUX_DIR "%s", file);

        return get_pxe_file(ctx, path, pxefile_addr_r);
}

/**
 * get_relfile_envaddr() - read a file to an address in an env var
 *
 * 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.
 *
 * @ctx: PXE context
 * @file_path: File path to read (relative to the PXE file)
 * @envaddr_name: Name of environment variable which contains the address to
 *      load to
 * @filesizep: Returns the file size in bytes
 * Returns 1 on success, -ENOENT if @envaddr_name does not exist as an
 *      environment variable, -EINVAL if its format is not valid hex, or other
 *      value < 0 on other error
 */
static int get_relfile_envaddr(struct pxe_context *ctx, const char *file_path,
                               const char *envaddr_name, ulong *filesizep)
{
        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(ctx, file_path, file_addr, filesizep);
}

/**
 * label_create() - crate a new PXE label
 *
 * Allocates memory for and initializes a pxe_label. This uses malloc, so the
 * result must be free()'d to reclaim the memory.
 *
 * Returns a pointer to the label, or NULL if out of memory
 */
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;
}

/**
 * label_destroy() - free the memory used by a pxe_label
 *
 * This frees @label itself as well as memory used by its name,
 * kernel, config, append, initrd, fdt, fdtdir and fdtoverlay 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.
 *
 * @label: Label to free
 */
static void label_destroy(struct pxe_label *label)
{
        free(label->name);
        free(label->kernel);
        free(label->config);
        free(label->append);
        free(label->initrd);
        free(label->fdt);
        free(label->fdtdir);
        free(label->fdtoverlays);
        free(label);
}

/**
 * label_print() - 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.
 *
 * @data: Label to print (is cast to struct pxe_label *)
 */
static void label_print(void *data)
{
        struct pxe_label *label = data;
        const char *c = label->menu ? label->menu : label->name;

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

/**
 * label_localboot() - Boot a label that specified 'localboot'
 *
 * This requires that the 'localcmd' environment variable is defined. Its
 * contents will be executed as U-Boot commands.  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'.
 *
 * @label: Label to process
 * 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) {
                char bootargs[CONFIG_SYS_CBSIZE];

                cli_simple_process_macros(label->append, bootargs,
                                          sizeof(bootargs));
                env_set("bootargs", bootargs);
        }

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

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

/**
 * label_boot_fdtoverlay() - Loads fdt overlays specified in 'fdtoverlays'
 *
 * @ctx: PXE context
 * @label: Label to process
 */
#ifdef CONFIG_OF_LIBFDT_OVERLAY
static void label_boot_fdtoverlay(struct pxe_context *ctx,
                                  struct pxe_label *label)
{
        char *fdtoverlay = label->fdtoverlays;
        struct fdt_header *working_fdt;
        char *fdtoverlay_addr_env;
        ulong fdtoverlay_addr;
        ulong fdt_addr;
        int err;

        /* Get the main fdt and map it */
        fdt_addr = hextoul(env_get("fdt_addr_r"), NULL);
        working_fdt = map_sysmem(fdt_addr, 0);
        err = fdt_check_header(working_fdt);
        if (err)
                return;

        /* Get the specific overlay loading address */
        fdtoverlay_addr_env = env_get("fdtoverlay_addr_r");
        if (!fdtoverlay_addr_env) {
                printf("Invalid fdtoverlay_addr_r for loading overlays\n");
                return;
        }

        fdtoverlay_addr = hextoul(fdtoverlay_addr_env, NULL);

        /* Cycle over the overlay files and apply them in order */
        do {
                struct fdt_header *blob;
                char *overlayfile;
                char *end;
                int len;

                /* Drop leading spaces */
                while (*fdtoverlay == ' ')
                        ++fdtoverlay;

                /* Copy a single filename if multiple provided */
                end = strstr(fdtoverlay, " ");
                if (end) {
                        len = (int)(end - fdtoverlay);
                        overlayfile = malloc(len + 1);
                        strncpy(overlayfile, fdtoverlay, len);
                        overlayfile[len] = '\0';
                } else
                        overlayfile = fdtoverlay;

                if (!strlen(overlayfile))
                        goto skip_overlay;

                /* Load overlay file */
                err = get_relfile_envaddr(ctx, overlayfile, "fdtoverlay_addr_r",
                                          NULL);
                if (err < 0) {
                        printf("Failed loading overlay %s\n", overlayfile);
                        goto skip_overlay;
                }

                /* Resize main fdt */
                fdt_shrink_to_minimum(working_fdt, 8192);

                blob = map_sysmem(fdtoverlay_addr, 0);
                err = fdt_check_header(blob);
                if (err) {
                        printf("Invalid overlay %s, skipping\n",
                               overlayfile);
                        goto skip_overlay;
                }

                err = fdt_overlay_apply_verbose(working_fdt, blob);
                if (err) {
                        printf("Failed to apply overlay %s, skipping\n",
                               overlayfile);
                        goto skip_overlay;
                }

skip_overlay:
                if (end)
                        free(overlayfile);
        } while ((fdtoverlay = strstr(fdtoverlay, " ")));
}
#endif

/**
 * label_boot() - 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.
 *
 * @ctx: PXE context
 * @label: Label to process
 * Returns does not return on success, otherwise returns 0 if a localboot
 *      label was processed, or 1 on error
 */
static int label_boot(struct pxe_context *ctx, struct pxe_label *label)
{
        char *bootm_argv[] = { "bootm", NULL, NULL, NULL, NULL };
        char *zboot_argv[] = { "zboot", NULL, "0", NULL, NULL };
        char *kernel_addr = NULL;
        char *initrd_addr_str = NULL;
        char initrd_filesize[10];
        char initrd_str[28];
        char mac_str[29] = "";
        char ip_str[68] = "";
        char *fit_addr = NULL;
        int bootm_argc = 2;
        int zboot_argc = 3;
        int len = 0;
        ulong kernel_addr_r;
        void *buf;

        label_print(label);

        label->attempted = 1;

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

        if (!label->kernel) {
                printf("No kernel given, skipping %s\n",
                       label->name);
                return 1;
        }

        if (label->initrd) {
                ulong size;

                if (get_relfile_envaddr(ctx, label->initrd, "ramdisk_addr_r",
                                        &size) < 0) {
                        printf("Skipping %s for failure retrieving initrd\n",
                               label->name);
                        return 1;
                }

                initrd_addr_str = env_get("ramdisk_addr_r");
                strcpy(initrd_filesize, simple_xtoa(size));

                strncpy(initrd_str, initrd_addr_str, 18);
                strcat(initrd_str, ":");
                strncat(initrd_str, initrd_filesize, 9);
        }

        if (get_relfile_envaddr(ctx, label->kernel, "kernel_addr_r",
                                NULL) < 0) {
                printf("Skipping %s for failure retrieving kernel\n",
                       label->name);
                return 1;
        }

        if (label->ipappend & 0x1) {
                sprintf(ip_str, " ip=%s:%s:%s:%s",
                        env_get("ipaddr"), env_get("serverip"),
                        env_get("gatewayip"), env_get("netmask"));
        }

        if (IS_ENABLED(CONFIG_CMD_NET)) {
                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';
                }
        }

        if ((label->ipappend & 0x3) || label->append) {
                char bootargs[CONFIG_SYS_CBSIZE] = "";
                char finalbootargs[CONFIG_SYS_CBSIZE];

                if (strlen(label->append ?: "") +
                    strlen(ip_str) + strlen(mac_str) + 1 > sizeof(bootargs)) {
                        printf("bootarg overflow %zd+%zd+%zd+1 > %zd\n",
                               strlen(label->append ?: ""),
                               strlen(ip_str), strlen(mac_str),
                               sizeof(bootargs));
                        return 1;
                }

                if (label->append)
                        strncpy(bootargs, label->append, sizeof(bootargs));

                strcat(bootargs, ip_str);
                strcat(bootargs, mac_str);

                cli_simple_process_macros(bootargs, finalbootargs,
                                          sizeof(finalbootargs));
                env_set("bootargs", finalbootargs);
                printf("append: %s\n", finalbootargs);
        }

        kernel_addr = env_get("kernel_addr_r");

        /* for FIT, append the configuration identifier */
        if (label->config) {
                int len = strlen(kernel_addr) + strlen(label->config) + 1;

                fit_addr = malloc(len);
                if (!fit_addr) {
                        printf("malloc fail (FIT address)\n");
                        return 1;
                }
                snprintf(fit_addr, len, "%s%s", kernel_addr, label->config);
                kernel_addr = fit_addr;
        }

        /*
         * fdt usage is optional:
         * It handles the following scenarios.
         *
         * Scenario 1: If fdt_addr_r specified and "fdt" or "fdtdir" label is
         * defined in pxe file, retrieve fdt blob from server. Pass fdt_addr_r to
         * bootm, and adjust argc appropriately.
         *
         * If retrieve fails and no exact fdt blob is specified in pxe file with
         * "fdt" label, try Scenario 2.
         *
         * 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] = env_get("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 = env_get("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 = env_get("soc");
                                f2 = "-";
                                f3 = env_get("board");
                                f4 = ".dtb";
                                if (!f1) {
                                        f1 = "";
                                        f2 = "";
                                }
                                if (!f3) {
                                        f2 = "";
                                        f3 = "";
                                }
                        }

                        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)\n");
                                goto cleanup;
                        }

                        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(ctx, fdtfile,
                                                      "fdt_addr_r", NULL);

                        free(fdtfilefree);
                        if (err < 0) {
                                bootm_argv[3] = NULL;

                                if (label->fdt) {
                                        printf("Skipping %s for failure retrieving FDT\n",
                                               label->name);
                                        goto cleanup;
                                }
                        }

#ifdef CONFIG_OF_LIBFDT_OVERLAY
                        if (label->fdtoverlays)
                                label_boot_fdtoverlay(ctx, label);
#endif
                } else {
                        bootm_argv[3] = NULL;
                }
        }

        bootm_argv[1] = kernel_addr;
        zboot_argv[1] = kernel_addr;

        if (initrd_addr_str) {
                bootm_argv[2] = initrd_str;
                bootm_argc = 3;

                zboot_argv[3] = initrd_addr_str;
                zboot_argv[4] = initrd_filesize;
                zboot_argc = 5;
        }

        if (!bootm_argv[3])
                bootm_argv[3] = env_get("fdt_addr");

        if (bootm_argv[3]) {
                if (!bootm_argv[2])
                        bootm_argv[2] = "-";
                bootm_argc = 4;
        }

        kernel_addr_r = genimg_get_kernel_addr(kernel_addr);
        buf = map_sysmem(kernel_addr_r, 0);
        /* Try bootm for legacy and FIT format image */
        if (genimg_get_format(buf) != IMAGE_FORMAT_INVALID)
                do_bootm(ctx->cmdtp, 0, bootm_argc, bootm_argv);
        /* Try booting an AArch64 Linux kernel image */
        else if (IS_ENABLED(CONFIG_CMD_BOOTI))
                do_booti(ctx->cmdtp, 0, bootm_argc, bootm_argv);
        /* Try booting a Image */
        else if (IS_ENABLED(CONFIG_CMD_BOOTZ))
                do_bootz(ctx->cmdtp, 0, bootm_argc, bootm_argv);
        /* Try booting an x86_64 Linux kernel image */
        else if (IS_ENABLED(CONFIG_CMD_ZBOOT))
                do_zboot_parent(ctx->cmdtp, 0, zboot_argc, zboot_argv, NULL);

        unmap_sysmem(buf);

cleanup:
        free(fit_addr);

        return 1;
}

/** enum token_type - 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_FDTOVERLAYS,
        T_ONTIMEOUT,
        T_IPAPPEND,
        T_BACKGROUND,
        T_INVALID
};

/** struct token - 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},
        {"fdtoverlays", T_FDTOVERLAYS},
        {"ontimeout", T_ONTIMEOUT,},
        {"ipappend", T_IPAPPEND,},
        {"background", T_BACKGROUND,},
        {NULL, T_INVALID}
};

/**
 * enum lex_state - lexer state
 *
 * 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.
 *
 * This is 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.
 *
 * Memory for t->val is allocated using malloc and must be free()'d to reclaim
 * it.
 *
 * @p: Points to a pointer to the current position in the input being processed.
 *      Updated to point at the first character after the current token
 * @t: Pointers to a token to fill in
 * @delim: Delimiter character to look for, either newline or space
 * @lower: true to convert the string to lower case when storing
 * Returns the new value of t->val, on success, NULL if out of memory
 */
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 = *p;
        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;
}

/**
 * get_keyword() - Populate a keyword token with a type and value
 *
 * Updates the ->type field based on the keyword string in @val
 * @t: Token to populate
 */
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_token() - 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: Points to a pointer to the current position in the input being processed.
 *      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 != '\n')
                        c++;
        }

        if (*c == '\n') {
                t->type = T_EOL;
                c++;
        } else if (*c == '\0') {
                t->type = T_EOF;
                c++;
        } else if (state == L_SLITERAL) {
                get_string(&c, t, '\n', 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;
}

/**
 * eol_or_eof() - Find end of line
 *
 * Increment *c until we get to the end of the current line, or EOF
 *
 * @c: Points to a pointer to the current position in the input being processed.
 *      Updated to point at the first character after the current token
 */
static void eol_or_eof(char **c)
{
        while (**c && **c != '\n')
                (*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\n", (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\n", (int)(*c - s), s);
                return -EINVAL;
        }

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

        free(t.val);

        return 1;
}

static int parse_pxefile_top(struct pxe_context *ctx, char *p, ulong base,
                             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(struct pxe_context *ctx, char **c, unsigned long base,
                          struct pxe_menu *cfg, int nest_level)
{
        char *include_path;
        char *s = *c;
        int err;
        char *buf;
        int ret;

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

        err = get_pxe_file(ctx, include_path, base);
        if (err < 0) {
                printf("Couldn't retrieve %s\n", include_path);
                return err;
        }

        buf = map_sysmem(base, 0);
        ret = parse_pxefile_top(ctx, buf, base, cfg, nest_level);
        unmap_sysmem(buf);

        return ret;
}

/*
 * Parse lines that begin with 'menu'.
 *
 * base and nest are provided to handle the 'menu include' case.
 *

 * base should point to a location where it's safe to store the included file.
 *
 * 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(struct pxe_context *ctx, char **c, struct pxe_menu *cfg,
                      unsigned long base, 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(ctx, c, base, cfg, nest_level + 1);
                break;

        case T_BACKGROUND:
                err = parse_sliteral(c, &cfg->bmp);
                break;

        default:
                printf("Ignoring malformed menu command: %.*s\n",
                       (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\n",
                       (int)(*c - s), s);
        }

        eol_or_eof(c);

        return 0;
}

/*
 * Handles parsing a 'kernel' label.
 * expecting "filename" or "<fit_filename>#cfg"
 */
static int parse_label_kernel(char **c, struct pxe_label *label)
{
        char *s;
        int err;

        err = parse_sliteral(c, &label->kernel);
        if (err < 0)
                return err;

        s = strstr(label->kernel, "#");
        if (!s)
                return 1;

        label->config = malloc(strlen(s) + 1);
        if (!label->config)
                return -ENOMEM;

        strcpy(label->config, s);
        *s = 0;

        return 1;
}

/*
 * 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\n", (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_label_kernel(c, label);
                        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_FDTOVERLAYS:
                        if (!label->fdtoverlays)
                                err = parse_sliteral(c, &label->fdtoverlays);
                        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(struct pxe_context *ctx, char *p, unsigned long base,
                             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\n", 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(ctx, &p, cfg,
                                         base + ALIGN(strlen(b) + 1, 4),
                                         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(ctx, &p,
                                             base + 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\n",
                               (int)(p - s), s);
                        eol_or_eof(&p);
                }

                if (err < 0)
                        return err;
        }
}

/*
 */
void destroy_pxe_menu(struct pxe_menu *cfg)
{
        struct list_head *pos, *n;
        struct pxe_label *label;

        free(cfg->title);
        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);
}

struct pxe_menu *parse_pxefile(struct pxe_context *ctx, unsigned long menucfg)
{
        struct pxe_menu *cfg;
        char *buf;
        int r;

        cfg = malloc(sizeof(struct pxe_menu));
        if (!cfg)
                return NULL;

        memset(cfg, 0, sizeof(struct pxe_menu));

        INIT_LIST_HEAD(&cfg->labels);

        buf = map_sysmem(menucfg, 0);
        r = parse_pxefile_top(ctx, buf, menucfg, cfg, 1);
        unmap_sysmem(buf);
        if (r < 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, DIV_ROUND_UP(cfg->timeout, 10),
                        cfg->prompt, NULL, 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\n", cfg->default_label);
                }
        }

        return m;
}

/*
 * Try to boot any labels we have yet to attempt to boot.
 */
static void boot_unattempted_labels(struct pxe_context *ctx,
                                    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(ctx, label);
        }
}

void handle_pxe_menu(struct pxe_context *ctx, struct pxe_menu *cfg)
{
        void *choice;
        struct menu *m;
        int err;

        if (IS_ENABLED(CONFIG_CMD_BMP)) {
                /* display BMP if available */
                if (cfg->bmp) {
                        if (get_relfile(ctx, cfg->bmp, image_load_addr, NULL)) {
                                if (CONFIG_IS_ENABLED(CMD_CLS))
                                        run_command("cls", 0);
                                bmp_display(image_load_addr,
                                            BMP_ALIGN_CENTER, BMP_ALIGN_CENTER);
                        } else {
                                printf("Skipping background bmp %s for failure\n",
                                       cfg->bmp);
                        }
                }
        }

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

        boot_unattempted_labels(ctx, cfg);
}

int pxe_setup_ctx(struct pxe_context *ctx, struct cmd_tbl *cmdtp,
                  pxe_getfile_func getfile, void *userdata,
                  bool allow_abs_path, const char *bootfile)
{
        const char *last_slash;
        size_t path_len = 0;

        memset(ctx, '\0', sizeof(*ctx));
        ctx->cmdtp = cmdtp;
        ctx->getfile = getfile;
        ctx->userdata = userdata;
        ctx->allow_abs_path = allow_abs_path;

        /* figure out the boot directory, if there is one */
        if (bootfile && strlen(bootfile) >= MAX_TFTP_PATH_LEN)
                return -ENOSPC;
        ctx->bootdir = strdup(bootfile ? bootfile : "");
        if (!ctx->bootdir)
                return -ENOMEM;

        if (bootfile) {
                last_slash = strrchr(bootfile, '/');
                if (last_slash)
                        path_len = (last_slash - bootfile) + 1;
        }
        ctx->bootdir[path_len] = '\0';

        return 0;
}

void pxe_destroy_ctx(struct pxe_context *ctx)
{
        free(ctx->bootdir);
}

int pxe_process(struct pxe_context *ctx, ulong pxefile_addr_r, bool prompt)
{
        struct pxe_menu *cfg;

        cfg = parse_pxefile(ctx, pxefile_addr_r);
        if (!cfg) {
                printf("Error parsing config file\n");
                return 1;
        }

        if (prompt)
                cfg->prompt = 1;

        handle_pxe_menu(ctx, cfg);

        destroy_pxe_menu(cfg);

        return 0;
}