/*
 * dumpmem.c
 * 
 * Yoann Guillot
 * 2005-10-16
 *
 * takes a physical memory dump file, and dumps the content of a virtual memory range
 * from an offset in the physical memory to a PGD
 *
 * usage: dump <dumpfile> <pgd offset> [<virt start> <virt end>]
 */

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>

typedef unsigned long u32;

const void *ptr;	// mmap(physdump)
u32 sz;			// physdump length

void dump_mem(const u32 off, const u32 start, const u32 end)
{
	const u32 *pgd = ptr + off;
	const u32 *pt;
	u32 i, j;
	char dumpfile[255];
	int fd = -1;
	u32 raw, vstart, vend;

#define closefd do { if (fd != -1) { close(fd); fd = -1; } } while (0)
#define openfd(v) if (fd == -1) { \
	snprintf(dumpfile, 255, "dmp-%.8lx_%.8lX", off, v); \
	fd = open(dumpfile, O_WRONLY | O_CREAT | O_EXCL, 0644); \
	if (fd == -1) { \
		perror(dumpfile); \
		continue; \
	} }
	
	for (i = (start >> 22) ; i <= (end >> 22) ; i++) {
		// notpresent ?
		if (!(pgd[i] & 1)) {
			closefd;
			continue;
		}
		
		// 4M page ?
		if (pgd[i] & 0x80) {
			if (!(pgd[i] & 1)) {
				closefd;
				continue;
			}
			
			raw = pgd[i] & 0xFFC00000;
			vstart = (i << 22);
			vend = ((i+1) << 22) - 1;
			
			if (raw >= sz) {
				printf("big vpage %.8lX maps to %.8lX, outside physical memory\n",
						vstart, raw);
				continue;
			}

			if (vstart < start) {
				raw += start & 0x3FFFFF;
				vstart = start;
			}

			if (vend > end)
				vend = end;
			
			openfd(vstart);

// printf("pgd[%lu] = %.8lX, dumping %.8lX-%.8lX from %.8lX\n", i, pgd[i], vstart, vend, raw);
			if (write(fd, ptr + raw, vend - vstart + 1) == -1) {
				perror("write");
				closefd;
			}
			continue;
		}
		
		// 4k page
		raw = pgd[i] & 0xFFFFF000;
		if (raw >= sz) {
			fprintf(stderr, "invalid PGD: pde %lu (%.8lX) points outside memdump\n", i, pgd[i]);
			closefd;
			continue;
		}
		
		pt = ptr + raw;
		
		u32 jmin = 0, jmax = 1023;
		
		if (i == (start >> 22))
			jmin = (start >> 12) & 0x3ff;
		
		if (i == (end >> 22))
			jmax = (end >> 12) & 0x3ff;
		
		for (j=jmin ; j<=jmax ; j++) {
			if (!(pt[j] & 1)) {
				closefd;
				continue;
			}
			
			raw = pt[j] & 0xFFFFF000;
			vstart = (i << 22) + (j << 12);
			vend = (i << 22) + ((j+1) << 12) - 1;
			
			if (raw >= sz) {
				printf("vpage %.8lX maps to %.8lX, outside physical memory\n",
						vstart, raw);
				continue;
			}

			if (vstart < start) {
				raw += start & 0xFFF;
				vstart = start;
			}

			if (vend > end)
				vend = end;
			
			openfd(vstart);

// printf("pgd[%lu] = %.8lX, pt[%lu] = %.8lX, dumping %.8lX-%.8lX from %.8lX\n", i, pgd[i], j, pt[j], vstart, vend, raw);
			if (write(fd, ptr + raw, vend - vstart + 1) == -1) {
				perror("write");
				closefd;
			}
		}
	}
	closefd;
}

int main(int argc, char **argv)
{
	u32 pgd;
	u32 start, end;
	
	if (argc < 3) {
		fprintf(stderr, "usage: %s <physdump file> <pgd offset> [<vstart> <vend>]\n", argv[0]);
		exit(1);
	}

	int fd = open(argv[1], O_RDONLY);
	if (fd == -1) {
		perror("open");
		exit(1);
	}
	pgd = strtoul(argv[2], 0, 0);
	
	sz = 8*1024*1024;
	struct stat stat;
	if (!fstat(fd, &stat))
		sz = stat.st_size;
	
	if ((pgd & 0xFFF) || (pgd >= sz)) {
		fprintf(stderr, "invalid pgd !\n");
		return 1;
	}

	start = 0;
	end = 0xffffffff;

	if (argc > 3)
		start = strtoul(argv[3], 0, 0);
	if (argc > 4)
		end = strtoul(argv[4], 0, 0);
	
	ptr = mmap(0, sz, PROT_READ, MAP_PRIVATE, fd, 0);
	if (!ptr) {
		close(fd);
		perror("mmap");
		exit(1);
	}

	dump_mem(pgd, start, end);

	munmap((void *)ptr, sz);
	close(fd);
	printf("done\n");
	return 0;
}