/*
 * kexec: Linux boots Linux
 *
 * Copyright (C) 2003-2010  Eric Biederman (ebiederm@xmission.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation (version 2 of the License).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define _GNU_SOURCE
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>
#include <elf.h>
#include <boot/elf_boot.h>
#include <ip_checksum.h>
#include <x86/x86-linux.h>
#include "../../kexec.h"
#include "../../kexec-elf.h"
#include "../../kexec-syscall.h"
#include "kexec-x86_64.h"
#include "../i386/x86-linux-setup.h"
#include "../i386/crashdump-x86.h"
#include <arch/options.h>

static const int probe_debug = 0;

int bzImage64_probe(const char *buf, off_t len)
{
	const struct x86_linux_header *header;

	if ((uintmax_t)len < (uintmax_t)(2 * 512)) {
		if (probe_debug)
			fprintf(stderr, "File is too short to be a bzImage!\n");
		return -1;
	}
	header = (const struct x86_linux_header *)buf;
	if (memcmp(header->header_magic, "HdrS", 4) != 0) {
		if (probe_debug)
			fprintf(stderr, "Not a bzImage\n");
		return -1;
	}
	if (header->boot_sector_magic != 0xAA55) {
		if (probe_debug)
			fprintf(stderr, "No x86 boot sector present\n");
		/* No x86 boot sector present */
		return -1;
	}
	if (header->protocol_version < 0x020C) {
		if (probe_debug)
			fprintf(stderr, "Must be at least protocol version 2.12\n");
		/* Must be at least protocol version 2.12 */
		return -1;
	}
	if ((header->loadflags & 1) == 0) {
		if (probe_debug)
			fprintf(stderr, "zImage not a bzImage\n");
		/* Not a bzImage */
		return -1;
	}
	if ((header->xloadflags & 3) != 3) {
		if (probe_debug)
			fprintf(stderr, "Not a relocatable bzImage64\n");
		/* Must be KERNEL_64 and CAN_BE_LOADED_ABOVE_4G */
		return -1;
	}

#define XLF_EFI_KEXEC   (1 << 4)
	if ((header->xloadflags & XLF_EFI_KEXEC) == XLF_EFI_KEXEC)
		bzImage_support_efi_boot = 1;

	/* I've got a relocatable bzImage64 */
	if (probe_debug)
		fprintf(stderr, "It's a relocatable bzImage64\n");
	return 0;
}

void bzImage64_usage(void)
{
	printf( "    --entry-32bit         Use the kernels 32bit entry point.\n"
		"    --real-mode           Use the kernels real mode entry point.\n"
		"    --command-line=STRING Set the kernel command line to STRING.\n"
		"    --append=STRING       Set the kernel command line to STRING.\n"
		"    --reuse-cmdline       Use kernel command line from running system.\n"
		"    --initrd=FILE         Use FILE as the kernel's initial ramdisk.\n"
		"    --ramdisk=FILE        Use FILE as the kernel's initial ramdisk.\n"
		);
}

static int do_bzImage64_load(struct kexec_info *info,
			const char *kernel, off_t kernel_len,
			const char *command_line, off_t command_line_len,
			const char *initrd, off_t initrd_len)
{
	struct x86_linux_header setup_header;
	struct x86_linux_param_header *real_mode;
	int setup_sects;
	size_t size;
	int kern16_size;
	unsigned long setup_base, setup_size, setup_header_size;
	struct entry64_regs regs64;
	char *modified_cmdline;
	unsigned long cmdline_end;
	unsigned long align, addr, k_size;
	unsigned kern16_size_needed;

	/*
	 * Find out about the file I am about to load.
	 */
	if ((uintmax_t)kernel_len < (uintmax_t)(2 * 512))
		return -1;

	memcpy(&setup_header, kernel, sizeof(setup_header));
	setup_sects = setup_header.setup_sects;
	if (setup_sects == 0)
		setup_sects = 4;
	kern16_size = (setup_sects + 1) * 512;
	if (kernel_len < kern16_size) {
		fprintf(stderr, "BzImage truncated?\n");
		return -1;
	}

	if ((uintmax_t)command_line_len > (uintmax_t)setup_header.cmdline_size) {
		dbgprintf("Kernel command line too long for kernel!\n");
		return -1;
	}

	/* Need to append some command line parameters internally in case of
	 * taking crash dumps.
	 */
	if (info->kexec_flags & (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)) {
		modified_cmdline = xmalloc(COMMAND_LINE_SIZE);
		memset((void *)modified_cmdline, 0, COMMAND_LINE_SIZE);
		if (command_line) {
			strncpy(modified_cmdline, command_line,
					COMMAND_LINE_SIZE);
			modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
		}

		/* If panic kernel is being loaded, additional segments need
		 * to be created. load_crashdump_segments will take care of
		 * loading the segments as high in memory as possible, hence
		 * in turn as away as possible from kernel to avoid being
		 * stomped by the kernel.
		 */
		if (load_crashdump_segments(info, modified_cmdline, -1, 0) < 0)
			return -1;

		/* Use new command line buffer */
		command_line = modified_cmdline;
		command_line_len = strlen(command_line) + 1;
	}

	/* x86_64 purgatory could be anywhere */
	elf_rel_build_load(info, &info->rhdr, purgatory, purgatory_size,
				0x3000, -1, -1, 0);
	dbgprintf("Loaded purgatory at addr 0x%lx\n", info->rhdr.rel_addr);
	/* The argument/parameter segment */
	kern16_size_needed = kern16_size;
	if (kern16_size_needed < 4096)
		kern16_size_needed = 4096;
	setup_size = kern16_size_needed + command_line_len +
				PURGATORY_CMDLINE_SIZE;
	real_mode = xmalloc(setup_size);
	memset(real_mode, 0, setup_size);

	/* only copy setup_header */
	setup_header_size = kernel[0x201] + 0x202 - 0x1f1;
	if (setup_header_size > 0x7f)
		setup_header_size = 0x7f;
	memcpy((unsigned char *)real_mode + 0x1f1, kernel + 0x1f1,
		 setup_header_size);

	/* No real mode code will be executing. setup segment can be loaded
	 * anywhere as we will be just reading command line.
	 */
	setup_base = add_buffer(info, real_mode, setup_size, setup_size,
				16, 0x3000, -1, -1);

	dbgprintf("Loaded real_mode_data and command line at 0x%lx\n",
			setup_base);

	/* The main kernel segment */
	k_size = kernel_len - kern16_size;
	/* need to use run-time size for buffer searching */
	dbgprintf("kernel init_size 0x%x\n", real_mode->init_size);
	size = _ALIGN(real_mode->init_size, 4096);
	align = real_mode->kernel_alignment;
	addr = add_buffer(info, kernel + kern16_size, k_size,
			  size, align, 0x100000, -1, -1);
	if (addr == ULONG_MAX)
		die("can not load bzImage64");
	dbgprintf("Loaded 64bit kernel at 0x%lx\n", addr);

	/* Tell the kernel what is going on */
	setup_linux_bootloader_parameters_high(info, real_mode, setup_base,
			kern16_size_needed, command_line, command_line_len,
			initrd, initrd_len, 1); /* put initrd high too */

	elf_rel_get_symbol(&info->rhdr, "entry64_regs", &regs64,
				 sizeof(regs64));
	regs64.rbx = 0;           /* Bootstrap processor */
	regs64.rsi = setup_base;  /* Pointer to the parameters */
	regs64.rip = addr + 0x200; /* the entry point for startup_64 */
	regs64.rsp = elf_rel_get_addr(&info->rhdr, "stack_end"); /* Stack, unused */
	elf_rel_set_symbol(&info->rhdr, "entry64_regs", &regs64,
				 sizeof(regs64));

	cmdline_end = setup_base + kern16_size_needed + command_line_len - 1;
	elf_rel_set_symbol(&info->rhdr, "cmdline_end", &cmdline_end,
			   sizeof(unsigned long));

	/* Fill in the information BIOS calls would normally provide. */
	setup_linux_system_parameters(info, real_mode);

	return 0;
}

/* This assumes file is being loaded using file based kexec syscall */
int bzImage64_load_file(int argc, char **argv, struct kexec_info *info)
{
	int ret = 0;
	char *command_line = NULL, *tmp_cmdline = NULL;
	const char *ramdisk = NULL, *append = NULL;
	int entry_16bit = 0, entry_32bit = 0;
	int opt;
	int command_line_len;

	/* See options.h -- add any more there, too. */
	static const struct option options[] = {
		KEXEC_ARCH_OPTIONS
		{ "command-line",	1, 0, OPT_APPEND },
		{ "append",		1, 0, OPT_APPEND },
		{ "reuse-cmdline",	0, 0, OPT_REUSE_CMDLINE },
		{ "initrd",		1, 0, OPT_RAMDISK },
		{ "ramdisk",		1, 0, OPT_RAMDISK },
		{ "real-mode",		0, 0, OPT_REAL_MODE },
		{ "entry-32bit",	0, 0, OPT_ENTRY_32BIT },
		{ 0,			0, 0, 0 },
	};
	static const char short_options[] = KEXEC_ARCH_OPT_STR "d";

	while ((opt = getopt_long(argc, argv, short_options, options, 0)) != -1) {
		switch (opt) {
		default:
			/* Ignore core options */
			if (opt < OPT_ARCH_MAX)
				break;
		case OPT_APPEND:
			append = optarg;
			break;
		case OPT_REUSE_CMDLINE:
			tmp_cmdline = get_command_line();
			break;
		case OPT_RAMDISK:
			ramdisk = optarg;
			break;
		case OPT_REAL_MODE:
			entry_16bit = 1;
			break;
		case OPT_ENTRY_32BIT:
			entry_32bit = 1;
			break;
		}
	}
	command_line = concat_cmdline(tmp_cmdline, append);
	if (tmp_cmdline)
		free(tmp_cmdline);
	command_line_len = 0;
	if (command_line) {
		command_line_len = strlen(command_line) + 1;
	} else {
		command_line = strdup("\0");
		command_line_len = 1;
	}

	if (entry_16bit || entry_32bit) {
		fprintf(stderr, "Kexec2 syscall does not support 16bit"
			" or 32bit entry yet\n");
		ret = -1;
		goto out;
	}

	if (ramdisk) {
		info->initrd_fd = open(ramdisk, O_RDONLY);
		if (info->initrd_fd == -1) {
			fprintf(stderr, "Could not open initrd file %s:%s\n",
					ramdisk, strerror(errno));
			ret = -1;
			goto out;
		}
	}

	info->command_line = command_line;
	info->command_line_len = command_line_len;
	return ret;
out:
	free(command_line);
	return ret;
}

int bzImage64_load(int argc, char **argv, const char *buf, off_t len,
	struct kexec_info *info)
{
	char *command_line = NULL, *tmp_cmdline = NULL;
	const char *ramdisk = NULL, *append = NULL;
	char *ramdisk_buf;
	off_t ramdisk_length = 0;
	int command_line_len;
	int entry_16bit = 0, entry_32bit = 0;
	int opt;
	int result;

	if (info->file_mode)
		return bzImage64_load_file(argc, argv, info);

	/* See options.h -- add any more there, too. */
	static const struct option options[] = {
		KEXEC_ARCH_OPTIONS
		{ "command-line",	1, 0, OPT_APPEND },
		{ "append",		1, 0, OPT_APPEND },
		{ "reuse-cmdline",	0, 0, OPT_REUSE_CMDLINE },
		{ "initrd",		1, 0, OPT_RAMDISK },
		{ "ramdisk",		1, 0, OPT_RAMDISK },
		{ "real-mode",		0, 0, OPT_REAL_MODE },
		{ "entry-32bit",	0, 0, OPT_ENTRY_32BIT },
		{ 0,			0, 0, 0 },
	};
	static const char short_options[] = KEXEC_ARCH_OPT_STR "d";

	while ((opt = getopt_long(argc, argv, short_options, options, 0)) != -1) {
		switch (opt) {
		default:
			/* Ignore core options */
			if (opt < OPT_ARCH_MAX)
				break;
		case OPT_APPEND:
			append = optarg;
			break;
		case OPT_REUSE_CMDLINE:
			tmp_cmdline = get_command_line();
			break;
		case OPT_RAMDISK:
			ramdisk = optarg;
			break;
		case OPT_REAL_MODE:
			entry_16bit = 1;
			break;
		case OPT_ENTRY_32BIT:
			entry_32bit = 1;
			break;
		}
	}
	command_line = concat_cmdline(tmp_cmdline, append);
	if (tmp_cmdline)
		free(tmp_cmdline);
	command_line_len = 0;
	if (command_line) {
		command_line_len = strlen(command_line) + 1;
	} else {
		command_line = strdup("\0");
		command_line_len = 1;
	}
	ramdisk_buf = 0;
	if (ramdisk)
		ramdisk_buf = slurp_file(ramdisk, &ramdisk_length);

	if (entry_16bit || entry_32bit)
		result = do_bzImage_load(info, buf, len, command_line,
					command_line_len, ramdisk_buf,
					ramdisk_length, 0, 0, entry_16bit);
	else
		result = do_bzImage64_load(info, buf, len, command_line,
					command_line_len, ramdisk_buf,
					ramdisk_length);

	free(command_line);
	return result;
}