parse-bzimage.c - pub/scm/linux/kernel/git/mcgrof/linker-tables - Git at Google

 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>

 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>

 #define offsetof(TYPE, MEMBER)  ((size_t)&((TYPE *)0)->MEMBER)

 #define max(a,b)			\
 	({ __typeof__ (a) _a = (a);	\
 	   __typeof__ (b) _b = (b);	\
 		_a > _b ? _a : _b; })

 #define min(a,b)			\
 	({ __typeof__ (a) _a = (a);	\
 	   __typeof__ (b) _b = (b);	\
 		_a < _b ? _a : _b; })

 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

 /* struct boot_params has struct setup_header at 0ffset 0x1f1 */
 struct __attribute__((__packed__)) setup_header {
         uint8_t         _pad0[0x1f1];
         uint8_t         setup_sects;
         uint16_t        root_flags;
         uint32_t        syssize;
         uint16_t        ram_size;
         uint16_t        vid_mode;
         uint16_t        root_dev;
         uint16_t        boot_flag;
         uint16_t        jump;
         uint32_t        header;
 #define HDR_MAGIC               "HdrS"
 #define HDR_MAGIC_SZ    4
         uint16_t        version;
 #define VERSION(h,l)    (((h)<<8) | (l))
         uint32_t        realmode_swtch;
         uint16_t        start_sys;
         uint16_t        kernel_version;
         uint8_t         type_of_loader;
         uint8_t         loadflags;
         uint16_t        setup_move_size;
         uint32_t        code32_start;
         uint32_t        ramdisk_image;
         uint32_t        ramdisk_size;
         uint32_t        bootsect_kludge;
         uint16_t        heap_end_ptr;
         uint16_t        _pad1;
         uint32_t        cmd_line_ptr;
         uint32_t        initrd_addr_max;
         uint32_t        kernel_alignment;
         uint8_t         relocatable_kernel;
         uint8_t         _pad2[3];
         uint32_t        cmdline_size;
         uint32_t        hardware_subarch;
         uint64_t        hardware_subarch_data;
         uint32_t        payload_offset;
         uint32_t        payload_length;
 };

 void usage(char *argv[])
 {
 	fprintf(stderr, "Usage: %s <kernel-bzimage>\n", argv[0]);
 	exit(EXIT_FAILURE);
 }

 int main(int argc, char *argv[])
 {
 	FILE *f;
 	struct stat sb;
 	int ret = -EINVAL;;
 	const char *kernel_filename;
 	uint8_t header[8192], *setup, *kernel, *initrd_data;
 	int setup_size, initrd_size = 0, cmdline_size;
 	size_t kernel_size, read_size;
 	/* The xen way */
 	struct setup_header *hdr;
 	uint32_t hdr_int;
 	uint16_t protocol;

 	if (argc != 2)
 		goto err_out;

 	kernel_filename = argv[1];
 	ret = stat(kernel_filename, &sb);
 	if (ret == -1) {
 		fprintf(stderr, "Could not stat() file %s\n", kernel_filename);
 		goto err_out;
 	}

 	kernel_size = sb.st_size;

 	printf("kernel:\t%s\n", kernel_filename);
 	printf("kernel size:\t%lld bytes\n", kernel_size);

 	f = fopen(kernel_filename, "rb");
 	if (!f) {
 		fprintf(stderr, "unable to load kernel %s: %s\n",
 				kernel_filename, strerror(errno));
 	}

 	read_size = fread(header, 1, min(ARRAY_SIZE(header), kernel_size), f);
 	if (read_size != min(ARRAY_SIZE(header), kernel_size)) {
 		fprintf(stderr, "Invalid size read for %s: %d (%s)\n",
 				kernel_filename, read_size, strerror(errno));
 		goto err_out;
 	}

 	fprintf(stdout, "Going to parse kernel...\n\n");

 	memcpy(&hdr_int, HDR_MAGIC, sizeof(uint32_t));

 	hdr = (struct setup_header *) header;

 	/* Xen's check is by far the cleanest and easiest to read */
 	if (memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) != 0 ) {
 		fprintf(stderr, "Bad image magic\n");
 		fprintf(stdout, "Xen Expects:\t0x%08x\n", hdr_int);
 		fprintf(stderr, "On image:\t%0x\n", hdr->header);
 		goto err_out;
 	}

 	fprintf(stdout, "-------------------------------------------------\n");
 	if (hdr->setup_sects > 15) {
 		char kver_str[128];

 		fseek(f, hdr->kernel_version + 0x200, SEEK_SET);
 		fread(kver_str, 128, 1, f);
 		kver_str[127] = '\0';
 		fprintf(stdout, "Kernel version: %s\n", kver_str);
 	} else
 		fprintf(stdout, "No kernel version information available\n");

 	fprintf(stdout, "-------------------------------------------------\n");

 	fprintf(stdout, "Xen Expects:\t0x%08x\n", hdr_int);
 	fprintf(stdout, "Qemu Expects:\t0x%08x\n", 0x53726448);
 	fprintf(stdout, "On image:\t0x%08x\n", hdr->header);

 	fprintf(stdout, "\n\n");

 	/*
 	 * Qemu calls this protocol, on Xen and Linux this is the
 	 * boot protocol version. Xen requires at least 2.08.
 	 */
 	memcpy(&protocol, header+0x206, sizeof(uint16_t));
         fprintf(stdout, "bzImage protocol Version: v%d.%02d\n",
 		hdr->version >> 8, hdr->version & 0xff);
     	fprintf(stdout, "Xen hdr->version:\t%d\n", hdr->version);
     	fprintf(stdout, "Qemu protocol:\t\t%d\n", protocol);
     	fprintf(stdout, "Qemu VERSION(2,8):\t%d\n", VERSION(2,8));

     	fprintf(stdout, "\n-------------------------------------------------\n");
     	fprintf(stdout, "Boot protocol 2.07:\t0x%04x\t(supports hardware_subarch)\n", VERSION(2,7));
     	fprintf(stdout, "Boot protocol 2.08:\t0x%04x\n", VERSION(2,8));
     	fprintf(stdout, "Boot protocol 2.09:\t0x%04x\n", VERSION(2,9));
     	fprintf(stdout, "Boot protocol 2.10:\t0x%04x\n", VERSION(2,10));
     	fprintf(stdout, "Boot protocol 2.11:\t0x%04x\n", VERSION(2,11));
     	fprintf(stdout, "Boot protocol 2.12:\t0x%04x\n", VERSION(2,12));
     	fprintf(stdout, "Boot protocol 2.13:\t0x%04x\n", VERSION(2,13));

 	/*
 	 * Refer to:
 	 *
 	 * 	Documentation/x86/zero-page.txt
 	 * 	arch/x86/include/uapi/asm/bootparam.h
 	 *
 	 * Upon boot we also use the sruct setup_header on the
 	 * struct boot_params. On x86 32-bit this is on the first
 	 * page, aka "zero page", on 64-bit this can be anywhere.
 	 * Either way we know the sruct setup_header offset within
 	 * struct boot_parmams resides between [0x1f1 - 0x290]. Qemu
 	 * uses direct offsets from the struct boot_parmams as with:
 	 *
 	 *    header[0x211] |= 0x80;  // CAN_USE_HEAP
 	 *
 	 * If we want to modify qemu to add other fields we need to
 	 * know the offset. This program skips struct boot_params and
 	 * by placing setup_header at 0x1f1 with a pad. To get the
 	 * offset of fields we can simply use offsetof. To test
 	 * correctness we know qemu's code relies on an offset of
 	 * 0x211 for setup_header->loadflags. Test for that and
 	 * then compute the offset for hardware_subarch.
 	 */

 	/* Boot protocol >= 2.07 supports hardware_subarch */

     	fprintf(stdout, "\n\n");
     	fprintf(stdout, "Member\t\t\t\t\tOffset\tExpected\tMatch\n");
     	fprintf(stdout, "-------------------------------------------------------------------------\n");
     	fprintf(stdout, "setup_header->loadflags\t\t\t0x%04x\t0x0211\t\t%s\n",
 			offsetof(struct setup_header, loadflags),
 			offsetof(struct setup_header, loadflags) == 0x0211 ?
 			"YES" : "NO!");
     	fprintf(stdout, "setup_header->hardware_subarch\t\t0x%04x\n",
 			offsetof(struct setup_header, hardware_subarch));
     	fprintf(stdout, "setup_header->hardware_subarch_data\t0x%04x\n",
 			offsetof(struct setup_header, hardware_subarch_data));

 	exit(EXIT_SUCCESS);
 err_out:
 	usage(argv);
 	return ret;
 }
	#include <stdio.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>

	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>

	#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)

	#define max(a,b) \
	({ __typeof__ (a) _a = (a); \
	__typeof__ (b) _b = (b); \
	_a > _b ? _a : _b; })

	#define min(a,b) \
	({ __typeof__ (a) _a = (a); \
	__typeof__ (b) _b = (b); \
	_a < _b ? _a : _b; })

	#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

	/* struct boot_params has struct setup_header at 0ffset 0x1f1 */
	struct __attribute__((__packed__)) setup_header {
	uint8_t _pad0[0x1f1];
	uint8_t setup_sects;
	uint16_t root_flags;
	uint32_t syssize;
	uint16_t ram_size;
	uint16_t vid_mode;
	uint16_t root_dev;
	uint16_t boot_flag;
	uint16_t jump;
	uint32_t header;
	#define HDR_MAGIC "HdrS"
	#define HDR_MAGIC_SZ 4
	uint16_t version;
	#define VERSION(h,l) (((h)<<8) \| (l))
	uint32_t realmode_swtch;
	uint16_t start_sys;
	uint16_t kernel_version;
	uint8_t type_of_loader;
	uint8_t loadflags;
	uint16_t setup_move_size;
	uint32_t code32_start;
	uint32_t ramdisk_image;
	uint32_t ramdisk_size;
	uint32_t bootsect_kludge;
	uint16_t heap_end_ptr;
	uint16_t _pad1;
	uint32_t cmd_line_ptr;
	uint32_t initrd_addr_max;
	uint32_t kernel_alignment;
	uint8_t relocatable_kernel;
	uint8_t _pad2[3];
	uint32_t cmdline_size;
	uint32_t hardware_subarch;
	uint64_t hardware_subarch_data;
	uint32_t payload_offset;
	uint32_t payload_length;
	};

	void usage(char *argv[])
	{
	fprintf(stderr, "Usage: %s <kernel-bzimage>\n", argv[0]);
	exit(EXIT_FAILURE);
	}

	int main(int argc, char *argv[])
	{
	FILE *f;
	struct stat sb;
	int ret = -EINVAL;;
	const char *kernel_filename;
	uint8_t header[8192], setup, kernel, *initrd_data;
	int setup_size, initrd_size = 0, cmdline_size;
	size_t kernel_size, read_size;
	/* The xen way */
	struct setup_header *hdr;
	uint32_t hdr_int;
	uint16_t protocol;

	if (argc != 2)
	goto err_out;

	kernel_filename = argv[1];
	ret = stat(kernel_filename, &sb);
	if (ret == -1) {
	fprintf(stderr, "Could not stat() file %s\n", kernel_filename);
	goto err_out;
	}

	kernel_size = sb.st_size;

	printf("kernel:\t%s\n", kernel_filename);
	printf("kernel size:\t%lld bytes\n", kernel_size);

	f = fopen(kernel_filename, "rb");
	if (!f) {
	fprintf(stderr, "unable to load kernel %s: %s\n",
	kernel_filename, strerror(errno));
	}

	read_size = fread(header, 1, min(ARRAY_SIZE(header), kernel_size), f);
	if (read_size != min(ARRAY_SIZE(header), kernel_size)) {
	fprintf(stderr, "Invalid size read for %s: %d (%s)\n",
	kernel_filename, read_size, strerror(errno));
	goto err_out;
	}

	fprintf(stdout, "Going to parse kernel...\n\n");

	memcpy(&hdr_int, HDR_MAGIC, sizeof(uint32_t));

	hdr = (struct setup_header *) header;

	/* Xen's check is by far the cleanest and easiest to read */
	if (memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) != 0 ) {
	fprintf(stderr, "Bad image magic\n");
	fprintf(stdout, "Xen Expects:\t0x%08x\n", hdr_int);
	fprintf(stderr, "On image:\t%0x\n", hdr->header);
	goto err_out;
	}

	fprintf(stdout, "-------------------------------------------------\n");
	if (hdr->setup_sects > 15) {
	char kver_str[128];

	fseek(f, hdr->kernel_version + 0x200, SEEK_SET);
	fread(kver_str, 128, 1, f);
	kver_str[127] = '\0';
	fprintf(stdout, "Kernel version: %s\n", kver_str);
	} else
	fprintf(stdout, "No kernel version information available\n");

	fprintf(stdout, "-------------------------------------------------\n");

	fprintf(stdout, "Xen Expects:\t0x%08x\n", hdr_int);
	fprintf(stdout, "Qemu Expects:\t0x%08x\n", 0x53726448);
	fprintf(stdout, "On image:\t0x%08x\n", hdr->header);

	fprintf(stdout, "\n\n");

	/*
	* Qemu calls this protocol, on Xen and Linux this is the
	* boot protocol version. Xen requires at least 2.08.
	*/
	memcpy(&protocol, header+0x206, sizeof(uint16_t));
	fprintf(stdout, "bzImage protocol Version: v%d.%02d\n",
	hdr->version >> 8, hdr->version & 0xff);
	fprintf(stdout, "Xen hdr->version:\t%d\n", hdr->version);
	fprintf(stdout, "Qemu protocol:\t\t%d\n", protocol);
	fprintf(stdout, "Qemu VERSION(2,8):\t%d\n", VERSION(2,8));

	fprintf(stdout, "\n-------------------------------------------------\n");
	fprintf(stdout, "Boot protocol 2.07:\t0x%04x\t(supports hardware_subarch)\n", VERSION(2,7));
	fprintf(stdout, "Boot protocol 2.08:\t0x%04x\n", VERSION(2,8));
	fprintf(stdout, "Boot protocol 2.09:\t0x%04x\n", VERSION(2,9));
	fprintf(stdout, "Boot protocol 2.10:\t0x%04x\n", VERSION(2,10));
	fprintf(stdout, "Boot protocol 2.11:\t0x%04x\n", VERSION(2,11));
	fprintf(stdout, "Boot protocol 2.12:\t0x%04x\n", VERSION(2,12));
	fprintf(stdout, "Boot protocol 2.13:\t0x%04x\n", VERSION(2,13));

	/*
	* Refer to:
	*
	* Documentation/x86/zero-page.txt
	* arch/x86/include/uapi/asm/bootparam.h
	*
	* Upon boot we also use the sruct setup_header on the
	* struct boot_params. On x86 32-bit this is on the first
	* page, aka "zero page", on 64-bit this can be anywhere.
	* Either way we know the sruct setup_header offset within
	* struct boot_parmams resides between [0x1f1 - 0x290]. Qemu
	* uses direct offsets from the struct boot_parmams as with:
	*
	* header[0x211] \|= 0x80; // CAN_USE_HEAP
	*
	* If we want to modify qemu to add other fields we need to
	* know the offset. This program skips struct boot_params and
	* by placing setup_header at 0x1f1 with a pad. To get the
	* offset of fields we can simply use offsetof. To test
	* correctness we know qemu's code relies on an offset of
	* 0x211 for setup_header->loadflags. Test for that and
	* then compute the offset for hardware_subarch.
	*/

	/* Boot protocol >= 2.07 supports hardware_subarch */

	fprintf(stdout, "\n\n");
	fprintf(stdout, "Member\t\t\t\t\tOffset\tExpected\tMatch\n");
	fprintf(stdout, "-------------------------------------------------------------------------\n");
	fprintf(stdout, "setup_header->loadflags\t\t\t0x%04x\t0x0211\t\t%s\n",
	offsetof(struct setup_header, loadflags),
	offsetof(struct setup_header, loadflags) == 0x0211 ?
	"YES" : "NO!");
	fprintf(stdout, "setup_header->hardware_subarch\t\t0x%04x\n",
	offsetof(struct setup_header, hardware_subarch));
	fprintf(stdout, "setup_header->hardware_subarch_data\t0x%04x\n",
	offsetof(struct setup_header, hardware_subarch_data));

	exit(EXIT_SUCCESS);
	err_out:
	usage(argv);
	return ret;
	}