/*
 * Copyright (c) 2014 Roger Pau Monné <royger@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This multiboot implementation only implements a subset of the full
 * multiboot specification in order to be able to boot Xen and a
 * FreeBSD Dom0. Trying to use it to boot other multiboot compliant
 * kernels will most surely fail.
 *
 * The full multiboot specification can be found here:
 * http://www.gnu.org/software/grub/manual/multiboot/multiboot.html
 */

#include <sys/cdefs.h>

#include <sys/param.h>
#include <sys/exec.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/stdint.h>
#define _MACHINE_ELF_WANT_32BIT
#include <machine/elf.h>
#include <machine/metadata.h>
#include <machine/pc/bios.h>
#include <string.h>
#include <stand.h>

#include "bootstrap.h"
#include <sys/multiboot.h>
#include "vbe.h"
#include "libzfs.h"
#include "libi386.h"
#include "../btx/lib/btxv86.h"

#define	SUPPORT_DHCP
#include <bootp.h>

#define MULTIBOOT_SUPPORTED_FLAGS \
	(MULTIBOOT_AOUT_KLUDGE|MULTIBOOT_PAGE_ALIGN|MULTIBOOT_MEMORY_INFO)
#define METADATA_FIXED_SIZE	(PAGE_SIZE*4)
#define METADATA_MODULE_SIZE	PAGE_SIZE

#define METADATA_RESV_SIZE(mod_num) \
	roundup(METADATA_FIXED_SIZE + METADATA_MODULE_SIZE * mod_num, PAGE_SIZE)

/* MB data heap pointer */
static vm_offset_t last_addr;

static int multiboot_loadfile(char *, u_int64_t, struct preloaded_file **);
static int multiboot_exec(struct preloaded_file *);

static int multiboot_obj_loadfile(char *, u_int64_t, struct preloaded_file **);
static int multiboot_obj_exec(struct preloaded_file *fp);

struct file_format multiboot = { multiboot_loadfile, multiboot_exec };
struct file_format multiboot_obj =
    { multiboot_obj_loadfile, multiboot_obj_exec };

static int
num_modules(struct preloaded_file *kfp)
{
	struct kernel_module	*kmp;
	int			 mod_num = 0;

	for (kmp = kfp->f_modules; kmp != NULL; kmp = kmp->m_next)
		mod_num++;

	return (mod_num);
}

static int
multiboot_loadfile(char *filename, u_int64_t dest,
    struct preloaded_file **result)
{
	uint32_t		*magic;
	int			 i, error;
	caddr_t			 header_search;
	ssize_t			 search_size;
	int			 fd;
	struct multiboot_header	*header;
	struct preloaded_file	*fp;

	if (filename == NULL)
		return (EFTYPE);

	/* is kernel already loaded? */
	fp = file_findfile(NULL, NULL);
	if (fp != NULL) {
		return (EFTYPE);
	}

	if ((fd = open(filename, O_RDONLY)) == -1)
		return (errno);

	/*
	 * Read MULTIBOOT_SEARCH size in order to search for the
	 * multiboot magic header.
	 */
	header_search = malloc(MULTIBOOT_SEARCH);
	if (header_search == NULL) {
		close(fd);
		return (ENOMEM);
	}

	search_size = read(fd, header_search, MULTIBOOT_SEARCH);
	magic = (uint32_t *)header_search;

	header = NULL;
	for (i = 0; i < (search_size / sizeof(uint32_t)); i++) {
		if (magic[i] == MULTIBOOT_HEADER_MAGIC) {
			header = (struct multiboot_header *)&magic[i];
			break;
		}
	}

	if (header == NULL) {
		error = EFTYPE;
		goto out;
	}

	/* Valid multiboot header has been found, validate checksum */
	if (header->magic + header->flags + header->checksum != 0) {
		printf(
	"Multiboot checksum failed, magic: 0x%x flags: 0x%x checksum: 0x%x\n",
	header->magic, header->flags, header->checksum);
		error = EFTYPE;
		goto out;
	}

	if ((header->flags & ~MULTIBOOT_SUPPORTED_FLAGS) != 0) {
		printf("Unsupported multiboot flags found: 0x%x\n",
		    header->flags);
		error = EFTYPE;
		goto out;
	}
	/* AOUT KLUDGE means we just load entire flat file as blob */
	if (header->flags & MULTIBOOT_AOUT_KLUDGE) {
		vm_offset_t laddr;
		int got;

		dest = header->load_addr;
		if (lseek(fd, 0, SEEK_SET) == -1) {
			printf("lseek failed\n");
			error = EIO;
			goto out;
		}
		laddr = dest;
		for (;;) {
			got = archsw.arch_readin(fd, laddr, 4096);
			if (got == 0)
				break;
			if (got < 0) {
				printf("error reading: %s", strerror(errno));
				error = EIO;
				goto out;
			}
			laddr += got;
		}

		fp = file_alloc();
		if (fp == NULL) {
			error = ENOMEM;
			goto out;
		}
		fp->f_name = strdup(filename);
		fp->f_type = strdup("aout multiboot kernel");
		fp->f_addr = header->entry_addr;
		fp->f_size = laddr - dest;
		if (fp->f_size == 0) {
			file_discard(fp);
			error = EIO;
			goto out;
		}
		fp->f_metadata = NULL;
		error = 0;
	} else {
		error = elf32_loadfile_raw(filename, dest, &fp, 1);
		if (error != 0) {
			printf("elf32_loadfile_raw failed: %d unable to "
			    "load multiboot kernel\n", error);
			goto out;
		}
	}

	setenv("kernelname", fp->f_name, 1);
	bios_addsmapdata(fp);
	*result = fp;
out:
	free(header_search);
	close(fd);
	return (error);
}

/*
 * returns allocated virtual address from MB info area
 */
static vm_offset_t
mb_malloc(size_t n)
{
	vm_offset_t ptr = last_addr;
	if (ptr + n >= high_heap_base)
		return (0);
	last_addr = roundup(last_addr + n, MULTIBOOT_INFO_ALIGN);
	return (ptr);
}

static int
multiboot_exec(struct preloaded_file *fp)
{
	struct preloaded_file		*mfp;
	vm_offset_t			 entry;
	struct file_metadata		*md;
	struct multiboot_info		*mb_info = NULL;
	struct multiboot_mod_list	*mb_mod = NULL;
	multiboot_memory_map_t		*mmap;
	struct bios_smap		*smap;
	struct devdesc			*rootdev;
	char				*cmdline = NULL;
	size_t				 len;
	int				 error, num, i;
	int				 rootfs = 0;	/* flag for rootfs */
	int				 xen = 0;	/* flag for xen */
	int				 kernel = 0;	/* flag for kernel */

	/* Set up base for mb_malloc. */
	for (mfp = fp; mfp->f_next != NULL; mfp = mfp->f_next);

	/* Start info block from new page. */
	last_addr = roundup(mfp->f_addr + mfp->f_size, MULTIBOOT_MOD_ALIGN);

	/* Allocate the multiboot struct and fill the basic details. */
	mb_info = (struct multiboot_info *)PTOV(mb_malloc(sizeof (*mb_info)));

	bzero(mb_info, sizeof(struct multiboot_info));
	mb_info->flags = MULTIBOOT_INFO_MEMORY|MULTIBOOT_INFO_BOOT_LOADER_NAME;
	mb_info->mem_lower = bios_basemem / 1024;
	mb_info->mem_upper = bios_extmem / 1024;
	mb_info->boot_loader_name = mb_malloc(strlen(bootprog_info) + 1);

	i386_copyin(bootprog_info, mb_info->boot_loader_name,
	    strlen(bootprog_info) + 1);

	i386_getdev((void **)(&rootdev), NULL, NULL);
	if (rootdev == NULL) {
		printf("can't determine root device\n");
		error = EINVAL;
		goto error;
	}

	/*
	 * Boot image command line. If args were not provided, we need to set
	 * args here, and that depends on image type...
	 * Fortunately we only have following options:
	 * 64 or 32 bit unix or xen. So we just check if f_name has unix.
	 */
	/* Do we boot xen? */
	if (strstr(fp->f_name, "unix") == NULL)
		xen = 1;

	entry = fp->f_addr;

	num = 0;
	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		num++;
		if (mfp->f_type != NULL && strcmp(mfp->f_type, "rootfs") == 0)
			rootfs++;
		if (mfp->f_type != NULL && strcmp(mfp->f_type, "kernel") == 0)
			kernel++;
	}

	if (num == 0 || rootfs == 0) {
		/* We need at least one module - rootfs. */
		printf("No rootfs module provided, aborting\n");
		error = EINVAL;
		goto error;
	}
	if (xen == 1 && kernel == 0) {
		printf("No kernel module provided for xen, aborting\n");
		error = EINVAL;
		goto error;
	}
	mb_mod = (struct multiboot_mod_list *) PTOV(last_addr);
	last_addr += roundup(sizeof(*mb_mod) * num, MULTIBOOT_INFO_ALIGN);

	bzero(mb_mod, sizeof(*mb_mod) * num);

	num = 0;
	for (mfp = fp->f_next; mfp != NULL; mfp = mfp->f_next) {
		mb_mod[num].mod_start = mfp->f_addr;
		mb_mod[num].mod_end = mfp->f_addr + mfp->f_size;

		if (strcmp(mfp->f_type, "kernel") == 0) {
			cmdline = NULL;
			error = mb_kernel_cmdline(mfp, rootdev, &cmdline);
			if (error != 0)
				goto error;
		} else {
			len = strlen(mfp->f_name) + 1;
			len += strlen(mfp->f_type) + 5 + 1;
			if (mfp->f_args != NULL) {
				len += strlen(mfp->f_args) + 1;
			}
			cmdline = malloc(len);
			if (cmdline == NULL) {
				error = ENOMEM;
				goto error;
			}

			if (mfp->f_args != NULL)
				snprintf(cmdline, len, "%s type=%s %s",
				    mfp->f_name, mfp->f_type, mfp->f_args);
			else
				snprintf(cmdline, len, "%s type=%s",
				    mfp->f_name, mfp->f_type);
		}

		mb_mod[num].cmdline = mb_malloc(strlen(cmdline)+1);
		i386_copyin(cmdline, mb_mod[num].cmdline, strlen(cmdline)+1);
		free(cmdline);
		num++;
	}

	mb_info->mods_count = num;
	mb_info->mods_addr = VTOP(mb_mod);
	mb_info->flags |= MULTIBOOT_INFO_MODS;

	md = file_findmetadata(fp, MODINFOMD_SMAP);
	if (md == NULL) {
		printf("no memory smap\n");
		error = EINVAL;
		goto error;
	}

	num = md->md_size / sizeof(struct bios_smap); /* number of entries */
	mmap = (multiboot_memory_map_t *)PTOV(mb_malloc(sizeof(*mmap) * num));

	mb_info->mmap_length = num * sizeof(*mmap);
	smap = (struct bios_smap *)md->md_data;

	for (i = 0; i < num; i++) {
		mmap[i].size = sizeof(*smap);
		mmap[i].addr = smap[i].base;
		mmap[i].len = smap[i].length;
		mmap[i].type = smap[i].type;
	}
	mb_info->mmap_addr = VTOP(mmap);
	mb_info->flags |= MULTIBOOT_INFO_MEM_MAP;

	if (strstr(getenv("loaddev"), "net") != NULL &&
	    bootp_response != NULL) {
		mb_info->drives_length = bootp_response_size;
		mb_info->drives_addr = mb_malloc(bootp_response_size);
		i386_copyin(bootp_response, mb_info->drives_addr,
		    bootp_response_size);
		mb_info->flags &= ~MULTIBOOT_INFO_DRIVE_INFO;
	}
	/*
	 * Set the image command line. Need to do this as last thing,
	 * as illumos kernel dboot_startkern will check cmdline
	 * address as last check to find first free address.
	 */
	if (fp->f_args == NULL) {
		if (xen)
			cmdline = getenv("xen_cmdline");
		else
			cmdline = getenv("boot-args");
		if (cmdline != NULL) {
			fp->f_args = strdup(cmdline);
			if (fp->f_args == NULL) {
				error = ENOMEM;
				goto error;
			}
		}
	}

	/*
	 * If the image is xen, we just use f_name + f_args for commandline
	 * for unix, we need to add zfs-bootfs.
	 */
	if (xen) {
		len = strlen(fp->f_name) + 1;
		if (fp->f_args != NULL)
			len += strlen(fp->f_args) + 1;

		if (fp->f_args != NULL) {
			if((cmdline = malloc(len)) == NULL) {
				error = ENOMEM;
				goto error;
			}
			snprintf(cmdline, len, "%s %s", fp->f_name, fp->f_args);
		} else {
			cmdline = strdup(fp->f_name);
			if (cmdline == NULL) {
				error = ENOMEM;
				goto error;
			}
		}
	} else {
		cmdline = NULL;
		if ((error = mb_kernel_cmdline(fp, rootdev, &cmdline)) != 0)
			goto error;
	}

	mb_info->cmdline = mb_malloc(strlen(cmdline)+1);
	i386_copyin(cmdline, mb_info->cmdline, strlen(cmdline)+1);
	mb_info->flags |= MULTIBOOT_INFO_CMDLINE;
	free(cmdline);
	cmdline = NULL;

	/* make sure we have text mode */
	bios_set_text_mode(VGA_TEXT_MODE);

	dev_cleanup();
	__exec((void *)VTOP(multiboot_tramp), MULTIBOOT_BOOTLOADER_MAGIC,
	    (void *)entry, (void *)VTOP(mb_info));

	panic("exec returned");

error:
	free(cmdline);
	return (error);
}

static int
multiboot_obj_loadfile(char *filename, u_int64_t dest,
    struct preloaded_file **result)
{
	struct preloaded_file	*mfp, *kfp, *rfp;
	int			 error, mod_num;

	/* See if there's a aout multiboot kernel loaded */
	mfp = file_findfile(NULL, "aout multiboot kernel");
	if (mfp != NULL) {
		/* we have normal kernel loaded, add module */
		rfp = file_loadraw(filename, "module", 0, NULL, 0);
		if (rfp == NULL) {
			printf(
			"Unable to load %s as a multiboot payload module\n",
			filename);
			return (EINVAL);
		}
		rfp->f_size = roundup(rfp->f_size, PAGE_SIZE);
		*result = rfp;
		return (0);
	}

	/* See if there's a multiboot kernel loaded */
	mfp = file_findfile(NULL, "elf multiboot kernel");
	if (mfp == NULL) {
		return (EFTYPE);	/* this allows to check other methods */
	}

	/*
	 * We have a multiboot kernel loaded, see if there's a
	 * kernel loaded also.
	 */
	kfp = file_findfile(NULL, "elf kernel");
	if (kfp == NULL) {
		/*
		 * No kernel loaded, this must be it. The kernel has to
		 * be loaded as a raw file, it will be processed by
		 * Xen and correctly loaded as an ELF file.
		 */
		rfp = file_loadraw(filename, "elf kernel", 0, NULL, 0);
		if (rfp == NULL) {
			printf(
			"Unable to load %s as a multiboot payload kernel\n",
			filename);
			return (EINVAL);
		}

		/* Load kernel metadata... */
		setenv("kernelname", filename, 1);
		error = elf64_load_modmetadata(rfp, rfp->f_addr + rfp->f_size);
		if (error) {
			printf("Unable to load kernel %s metadata error: %d\n",
			    rfp->f_name, error);
			return (EINVAL);
		}

		/*
		 * Save space at the end of the kernel in order to place
		 * the metadata information. We do an approximation of the
		 * max metadata size, this is not optimal but it's probably
		 * the best we can do at this point. Once all modules are
		 * loaded and the size of the metadata is known this
		 * space will be recovered if not used.
		 */
		mod_num = num_modules(rfp);
		rfp->f_size = roundup(rfp->f_size, PAGE_SIZE);
		rfp->f_size += METADATA_RESV_SIZE(mod_num);
		*result = rfp;
	} else {
		/* The rest should be loaded as regular modules */
		error = elf64_obj_loadfile(filename, dest, result);
		if (error != 0) {
			printf("Unable to load %s as an object file, error: %d",
			    filename, error);
			return (error);
		}
	}

	return (0);
}

static int
multiboot_obj_exec(struct preloaded_file *fp __unused)
{

	return (EFTYPE);
}