Joshua Wise's Git repositories - netwatch.git/blame_incremental

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Commit	Line	Data
	1	#include <string.h>
	2	#include <stdio.h>
	3	#include "elf.h"
	4	#include <stdlib.h>
	5	#include <unistd.h>
	6	#include <errno.h>
	7	#include <signal.h>
	8	#include <fcntl.h>
	9	#include <ctype.h>
	10	#include <termios.h>
	11	#include <sys/types.h>
	12	#include <sys/mman.h>
	13	#include <sys/stat.h>
	14
	15	#define FATAL do { fprintf(stderr, "Error at %s:%d (%d) [%s]\n", \
	16	__FILE__, __LINE__, errno, strerror(errno)); exit(1); } while(0)
	17
	18	#define MAP_SIZE 131072
	19	#define MAP_MASK (4096 - 1)
	20
	21	char * snarf_file(char * fname) {
	22
	23	int fd = open(fname, O_RDONLY);
	24	if (fd < 0) FATAL;
	25
	26	struct stat st;
	27	if (fstat(fd, &st) < 0) FATAL;
	28
	29	char * buf = malloc(st.st_size);
	30	if (!buf) FATAL;
	31	if (read(fd, buf, st.st_size) != st.st_size) FATAL;
	32
	33	printf("Loaded %d bytes.\n", st.st_size);
	34	return buf;
	35	}
	36
	37	void dump_to_ram (void * src, int target, int size) {
	38
	39	printf("Copying %d bytes to 0x%08x...\n", size, target);
	40
	41	int fd = open("/dev/mem", O_RDWR \| O_SYNC);
	42	if (fd < 0) FATAL;
	43
	44	void * map_base = mmap(0, MAP_SIZE, PROT_READ \| PROT_WRITE,
	45	MAP_SHARED, fd, target & ~MAP_MASK);
	46
	47	if (map_base == (void *) -1) FATAL;
	48
	49	void * virt_addr = map_base + (target & MAP_MASK);
	50	memcpy(virt_addr, src, size);
	51
	52	}
	53
	54	static const unsigned char elf_ident[4] = { 0x7F, 'E', 'L', 'F' };
	55
	56	int load_elf (char * buf) {
	57
	58	Elf32_Ehdr * elf_hdr = (Elf32_Ehdr *) buf;
	59	Elf32_Shdr * elf_sec_hdrs = (Elf32_Shdr *) (buf + elf_hdr->e_shoff);
	60
	61	if (memcmp(elf_hdr->e_ident, elf_ident, sizeof(elf_ident))) FATAL;
	62	if (elf_hdr->e_type != ET_EXEC) FATAL;
	63	if (elf_hdr->e_machine != EM_386) FATAL;
	64	if (elf_hdr->e_version != EV_CURRENT) FATAL;
	65
	66	char * string_table = buf + elf_sec_hdrs[elf_hdr->e_shstrndx].sh_offset;
	67
	68	int i;
	69	for (i = 0; i < elf_hdr->e_shnum; i++) {
	70	if (elf_sec_hdrs[i].sh_name == SHN_UNDEF) {
	71	continue;
	72	}
	73
	74	char * section_name = string_table + elf_sec_hdrs[i].sh_name;
	75
	76	if (!(elf_sec_hdrs[i].sh_flags & SHF_ALLOC)) {
	77	printf("Skipping %s...\n", section_name);
	78	continue;
	79	}
	80
	81	printf("Loading %s...\n", section_name);
	82
	83	dump_to_ram(buf + elf_sec_hdrs[i].sh_offset,
	84	elf_sec_hdrs[i].sh_addr,
	85	elf_sec_hdrs[i].sh_size);
	86	}
	87
	88	return 0;
	89	}
	90
	91	int main(int argc, char **argv) {
	92	if (argc != 2) {
	93	printf("Usage: %s elffile\n", argv[0]);
	94	return 1;
	95	}
	96
	97	printf("Loading file...\n");
	98
	99	char * buf = snarf_file(argv[1]);
	100	load_elf(buf);
	101
	102	return 0;
	103	}
	104