[mirror_ubuntu-artful-kernel.git] / arch / i386 / boot / compressed / relocs.c

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <elf.h>
#include <byteswap.h>
#define USE_BSD
#include <endian.h>

#define MAX_SHDRS 100
static Elf32_Ehdr ehdr;
static Elf32_Shdr shdr[MAX_SHDRS];
static Elf32_Sym  *symtab[MAX_SHDRS];
static Elf32_Rel  *reltab[MAX_SHDRS];
static char *strtab[MAX_SHDRS];
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;

static void die(char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	exit(1);
}

static const char *sym_type(unsigned type)
{
	static const char *type_name[] = {
#define SYM_TYPE(X) [X] = #X
		SYM_TYPE(STT_NOTYPE),
		SYM_TYPE(STT_OBJECT),
		SYM_TYPE(STT_FUNC),
		SYM_TYPE(STT_SECTION),
		SYM_TYPE(STT_FILE),
		SYM_TYPE(STT_COMMON),
		SYM_TYPE(STT_TLS),
#undef SYM_TYPE
	};
	const char *name = "unknown sym type name";
	if (type < sizeof(type_name)/sizeof(type_name[0])) {
		name = type_name[type];
	}
	return name;
}

static const char *sym_bind(unsigned bind)
{
	static const char *bind_name[] = {
#define SYM_BIND(X) [X] = #X
		SYM_BIND(STB_LOCAL),
		SYM_BIND(STB_GLOBAL),
		SYM_BIND(STB_WEAK),
#undef SYM_BIND
	};
	const char *name = "unknown sym bind name";
	if (bind < sizeof(bind_name)/sizeof(bind_name[0])) {
		name = bind_name[bind];
	}
	return name;
}

static const char *sym_visibility(unsigned visibility)
{
	static const char *visibility_name[] = {
#define SYM_VISIBILITY(X) [X] = #X
		SYM_VISIBILITY(STV_DEFAULT),
		SYM_VISIBILITY(STV_INTERNAL),
		SYM_VISIBILITY(STV_HIDDEN),
		SYM_VISIBILITY(STV_PROTECTED),
#undef SYM_VISIBILITY
	};
	const char *name = "unknown sym visibility name";
	if (visibility < sizeof(visibility_name)/sizeof(visibility_name[0])) {
		name = visibility_name[visibility];
	}
	return name;
}

static const char *rel_type(unsigned type)
{
	static const char *type_name[] = {
#define REL_TYPE(X) [X] = #X
		REL_TYPE(R_386_NONE),
		REL_TYPE(R_386_32),
		REL_TYPE(R_386_PC32),
		REL_TYPE(R_386_GOT32),
		REL_TYPE(R_386_PLT32),
		REL_TYPE(R_386_COPY),
		REL_TYPE(R_386_GLOB_DAT),
		REL_TYPE(R_386_JMP_SLOT),
		REL_TYPE(R_386_RELATIVE),
		REL_TYPE(R_386_GOTOFF),
		REL_TYPE(R_386_GOTPC),
#undef REL_TYPE
	};
	const char *name = "unknown type rel type name";
	if (type < sizeof(type_name)/sizeof(type_name[0])) {
		name = type_name[type];
	}
	return name;
}

static const char *sec_name(unsigned shndx)
{
	const char *sec_strtab;
	const char *name;
	sec_strtab = strtab[ehdr.e_shstrndx];
	name = "<noname>";
	if (shndx < ehdr.e_shnum) {
		name = sec_strtab + shdr[shndx].sh_name;
	}
	else if (shndx == SHN_ABS) {
		name = "ABSOLUTE";
	}
	else if (shndx == SHN_COMMON) {
		name = "COMMON";
	}
	return name;
}

static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
{
	const char *name;
	name = "<noname>";
	if (sym->st_name) {
		name = sym_strtab + sym->st_name;
	}
	else {
		name = sec_name(shdr[sym->st_shndx].sh_name);
	}
	return name;
}


#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
#endif
#if BYTE_ORDER == BIG_ENDIAN
#define le16_to_cpu(val) bswap_16(val)
#define le32_to_cpu(val) bswap_32(val)
#endif

static uint16_t elf16_to_cpu(uint16_t val)
{
	return le16_to_cpu(val);
}

static uint32_t elf32_to_cpu(uint32_t val)
{
	return le32_to_cpu(val);
}

static void read_ehdr(FILE *fp)
{
	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
		die("Cannot read ELF header: %s\n",
			strerror(errno));
	}
	if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
		die("No ELF magic\n");
	}
	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
		die("Not a 32 bit executable\n");
	}
	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
		die("Not a LSB ELF executable\n");
	}
	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	/* Convert the fields to native endian */
	ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
	ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
	ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
	ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
	ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
	ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
	ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
	ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
	ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
	ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
	ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);

	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
		die("Unsupported ELF header type\n");
	}
	if (ehdr.e_machine != EM_386) {
		die("Not for x86\n");
	}
	if (ehdr.e_version != EV_CURRENT) {
		die("Unknown ELF version\n");
	}
	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
		die("Bad Elf header size\n");
	}
	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
		die("Bad program header entry\n");
	}
	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
		die("Bad section header entry\n");
	}
	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
		die("String table index out of bounds\n");
	}
}

static void read_shdrs(FILE *fp)
{
	int i;
	if (ehdr.e_shnum > MAX_SHDRS) {
		die("%d section headers supported: %d\n",
			ehdr.e_shnum, MAX_SHDRS);
	}
	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
		die("Seek to %d failed: %s\n",
			ehdr.e_shoff, strerror(errno));
	}
	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
		die("Cannot read ELF section headers: %s\n",
			strerror(errno));
	}
	for(i = 0; i < ehdr.e_shnum; i++) {
		shdr[i].sh_name      = elf32_to_cpu(shdr[i].sh_name);
		shdr[i].sh_type      = elf32_to_cpu(shdr[i].sh_type);
		shdr[i].sh_flags     = elf32_to_cpu(shdr[i].sh_flags);
		shdr[i].sh_addr      = elf32_to_cpu(shdr[i].sh_addr);
		shdr[i].sh_offset    = elf32_to_cpu(shdr[i].sh_offset);
		shdr[i].sh_size      = elf32_to_cpu(shdr[i].sh_size);
		shdr[i].sh_link      = elf32_to_cpu(shdr[i].sh_link);
		shdr[i].sh_info      = elf32_to_cpu(shdr[i].sh_info);
		shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
		shdr[i].sh_entsize   = elf32_to_cpu(shdr[i].sh_entsize);
	}

}

static void read_strtabs(FILE *fp)
{
	int i;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_STRTAB) {
			continue;
		}
		strtab[i] = malloc(shdr[i].sh_size);
		if (!strtab[i]) {
			die("malloc of %d bytes for strtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
	}
}

static void read_symtabs(FILE *fp)
{
	int i,j;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		symtab[i] = malloc(shdr[i].sh_size);
		if (!symtab[i]) {
			die("malloc of %d bytes for symtab failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
			symtab[i][j].st_name  = elf32_to_cpu(symtab[i][j].st_name);
			symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
			symtab[i][j].st_size  = elf32_to_cpu(symtab[i][j].st_size);
			symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
		}
	}
}


static void read_relocs(FILE *fp)
{
	int i,j;
	for(i = 0; i < ehdr.e_shnum; i++) {
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		reltab[i] = malloc(shdr[i].sh_size);
		if (!reltab[i]) {
			die("malloc of %d bytes for relocs failed\n",
				shdr[i].sh_size);
		}
		if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
			die("Seek to %d failed: %s\n",
				shdr[i].sh_offset, strerror(errno));
		}
		if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
			die("Cannot read symbol table: %s\n",
				strerror(errno));
		}
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
			reltab[i][j].r_info   = elf32_to_cpu(reltab[i][j].r_info);
		}
	}
}


static void print_absolute_symbols(void)
{
	int i;
	printf("Absolute symbols\n");
	printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		int j;
		if (shdr[i].sh_type != SHT_SYMTAB) {
			continue;
		}
		sh_symtab = symtab[i];
		sym_strtab = strtab[shdr[i].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
			Elf32_Sym *sym;
			const char *name;
			sym = &symtab[i][j];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}
			printf("%5d %08x %5d %10s %10s %12s %s\n",
				j, sym->st_value, sym->st_size,
				sym_type(ELF32_ST_TYPE(sym->st_info)),
				sym_bind(ELF32_ST_BIND(sym->st_info)),
				sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
				name);
		}
	}
	printf("\n");
}

static void print_absolute_relocs(void)
{
	int i;
	printf("Absolute relocations\n");
	printf("Offset     Info     Type     Sym.Value Sym.Name\n");
	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			const char *name;
			rel = &reltab[i][j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			name = sym_name(sym_strtab, sym);
			if (sym->st_shndx != SHN_ABS) {
				continue;
			}
			printf("%08x %08x %10s %08x  %s\n",
				rel->r_offset,
				rel->r_info,
				rel_type(ELF32_R_TYPE(rel->r_info)),
				sym->st_value,
				name);
		}
	}
	printf("\n");
}

static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
{
	int i;
	/* Walk through the relocations */
	for(i = 0; i < ehdr.e_shnum; i++) {
		char *sym_strtab;
		Elf32_Sym *sh_symtab;
		unsigned sec_applies, sec_symtab;
		int j;
		if (shdr[i].sh_type != SHT_REL) {
			continue;
		}
		sec_symtab  = shdr[i].sh_link;
		sec_applies = shdr[i].sh_info;
		if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
			continue;
		}
		sh_symtab = symtab[sec_symtab];
		sym_strtab = strtab[shdr[sec_symtab].sh_link];
		for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
			Elf32_Rel *rel;
			Elf32_Sym *sym;
			unsigned r_type;
			rel = &reltab[i][j];
			sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
			r_type = ELF32_R_TYPE(rel->r_info);
			/* Don't visit relocations to absolute symbols */
			if (sym->st_shndx == SHN_ABS) {
				continue;
			}
			if (r_type == R_386_PC32) {
				/* PC relative relocations don't need to be adjusted */
			}
			else if (r_type == R_386_32) {
				/* Visit relocations that need to be adjusted */
				visit(rel, sym);
			}
			else {
				die("Unsupported relocation type: %d\n", r_type);
			}
		}
	}
}

static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
	reloc_count += 1;
}

static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
{
	/* Remember the address that needs to be adjusted. */
	relocs[reloc_idx++] = rel->r_offset;
}

static int cmp_relocs(const void *va, const void *vb)
{
	const unsigned long *a, *b;
	a = va; b = vb;
	return (*a == *b)? 0 : (*a > *b)? 1 : -1;
}

static void emit_relocs(int as_text)
{
	int i;
	/* Count how many relocations I have and allocate space for them. */
	reloc_count = 0;
	walk_relocs(count_reloc);
	relocs = malloc(reloc_count * sizeof(relocs[0]));
	if (!relocs) {
		die("malloc of %d entries for relocs failed\n",
			reloc_count);
	}
	/* Collect up the relocations */
	reloc_idx = 0;
	walk_relocs(collect_reloc);

	/* Order the relocations for more efficient processing */
	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);

	/* Print the relocations */
	if (as_text) {
		/* Print the relocations in a form suitable that
		 * gas will like.
		 */
		printf(".section \".data.reloc\",\"a\"\n");
		printf(".balign 4\n");
		for(i = 0; i < reloc_count; i++) {
			printf("\t .long 0x%08lx\n", relocs[i]);
		}
		printf("\n");
	}
	else {
		unsigned char buf[4];
		buf[0] = buf[1] = buf[2] = buf[3] = 0;
		/* Print a stop */
		printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		/* Now print each relocation */
		for(i = 0; i < reloc_count; i++) {
			buf[0] = (relocs[i] >>  0) & 0xff;
			buf[1] = (relocs[i] >>  8) & 0xff;
			buf[2] = (relocs[i] >> 16) & 0xff;
			buf[3] = (relocs[i] >> 24) & 0xff;
			printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
		}
	}
}

static void usage(void)
{
	die("i386_reloc [--abs | --text] vmlinux\n");
}

int main(int argc, char **argv)
{
	int show_absolute;
	int as_text;
	const char *fname;
	FILE *fp;
	int i;

	show_absolute = 0;
	as_text = 0;
	fname = NULL;
	for(i = 1; i < argc; i++) {
		char *arg = argv[i];
		if (*arg == '-') {
			if (strcmp(argv[1], "--abs") == 0) {
				show_absolute = 1;
				continue;
			}
			else if (strcmp(argv[1], "--text") == 0) {
				as_text = 1;
				continue;
			}
		}
		else if (!fname) {
			fname = arg;
			continue;
		}
		usage();
	}
	if (!fname) {
		usage();
	}
	fp = fopen(fname, "r");
	if (!fp) {
		die("Cannot open %s: %s\n",
			fname, strerror(errno));
	}
	read_ehdr(fp);
	read_shdrs(fp);
	read_strtabs(fp);
	read_symtabs(fp);
	read_relocs(fp);
	if (show_absolute) {
		print_absolute_symbols();
		print_absolute_relocs();
		return 0;
	}
	emit_relocs(as_text);
	return 0;
}
Commit	Line	Data
968de4f0 EB	1	#include <stdio.h>
	2	#include <stdarg.h>
	3	#include <stdlib.h>
	4	#include <stdint.h>
	5	#include <string.h>
	6	#include <errno.h>
	7	#include <unistd.h>
	8	#include <elf.h>
	9	#include <byteswap.h>
	10	#define USE_BSD
	11	#include <endian.h>
	12
	13	#define MAX_SHDRS 100
	14	static Elf32_Ehdr ehdr;
	15	static Elf32_Shdr shdr[MAX_SHDRS];
	16	static Elf32_Sym *symtab[MAX_SHDRS];
	17	static Elf32_Rel *reltab[MAX_SHDRS];
	18	static char *strtab[MAX_SHDRS];
	19	static unsigned long reloc_count, reloc_idx;
	20	static unsigned long *relocs;
	21
	22	static void die(char *fmt, ...)
	23	{
	24	va_list ap;
	25	va_start(ap, fmt);
	26	vfprintf(stderr, fmt, ap);
	27	va_end(ap);
	28	exit(1);
	29	}
	30
	31	static const char *sym_type(unsigned type)
	32	{
	33	static const char *type_name[] = {
	34	#define SYM_TYPE(X) [X] = #X
	35	SYM_TYPE(STT_NOTYPE),
	36	SYM_TYPE(STT_OBJECT),
	37	SYM_TYPE(STT_FUNC),
	38	SYM_TYPE(STT_SECTION),
	39	SYM_TYPE(STT_FILE),
	40	SYM_TYPE(STT_COMMON),
	41	SYM_TYPE(STT_TLS),
	42	#undef SYM_TYPE
	43	};
	44	const char *name = "unknown sym type name";
	45	if (type < sizeof(type_name)/sizeof(type_name[0])) {
	46	name = type_name[type];
	47	}
	48	return name;
	49	}
	50
	51	static const char *sym_bind(unsigned bind)
	52	{
	53	static const char *bind_name[] = {
	54	#define SYM_BIND(X) [X] = #X
	55	SYM_BIND(STB_LOCAL),
	56	SYM_BIND(STB_GLOBAL),
	57	SYM_BIND(STB_WEAK),
	58	#undef SYM_BIND
	59	};
	60	const char *name = "unknown sym bind name";
	61	if (bind < sizeof(bind_name)/sizeof(bind_name[0])) {
	62	name = bind_name[bind];
	63	}
	64	return name;
65	}
66
67	static const char *sym_visibility(unsigned visibility)
68	{
69	static const char *visibility_name[] = {
70	#define SYM_VISIBILITY(X) [X] = #X
71	SYM_VISIBILITY(STV_DEFAULT),
72	SYM_VISIBILITY(STV_INTERNAL),
73	SYM_VISIBILITY(STV_HIDDEN),
74	SYM_VISIBILITY(STV_PROTECTED),
75	#undef SYM_VISIBILITY
76	};
77	const char *name = "unknown sym visibility name";
78	if (visibility < sizeof(visibility_name)/sizeof(visibility_name[0])) {
79	name = visibility_name[visibility];
80	}
81	return name;
82	}
83
84	static const char *rel_type(unsigned type)
85	{
86	static const char *type_name[] = {
87	#define REL_TYPE(X) [X] = #X
88	REL_TYPE(R_386_NONE),
89	REL_TYPE(R_386_32),
90	REL_TYPE(R_386_PC32),
91	REL_TYPE(R_386_GOT32),
92	REL_TYPE(R_386_PLT32),
93	REL_TYPE(R_386_COPY),
94	REL_TYPE(R_386_GLOB_DAT),
95	REL_TYPE(R_386_JMP_SLOT),
96	REL_TYPE(R_386_RELATIVE),
97	REL_TYPE(R_386_GOTOFF),
98	REL_TYPE(R_386_GOTPC),
99	#undef REL_TYPE
100	};
101	const char *name = "unknown type rel type name";
102	if (type < sizeof(type_name)/sizeof(type_name[0])) {
103	name = type_name[type];
104	}
105	return name;
106	}
107
108	static const char *sec_name(unsigned shndx)
109	{
110	const char *sec_strtab;
111	const char *name;
112	sec_strtab = strtab[ehdr.e_shstrndx];
113	name = "<noname>";
114	if (shndx < ehdr.e_shnum) {
115	name = sec_strtab + shdr[shndx].sh_name;
116	}
117	else if (shndx == SHN_ABS) {
118	name = "ABSOLUTE";
119	}
120	else if (shndx == SHN_COMMON) {
121	name = "COMMON";
122	}
123	return name;
124	}
125
126	static const char sym_name(const char sym_strtab, Elf32_Sym *sym)
127	{
128	const char *name;
129	name = "<noname>";
130	if (sym->st_name) {
131	name = sym_strtab + sym->st_name;
132	}
133	else {
134	name = sec_name(shdr[sym->st_shndx].sh_name);
135	}
136	return name;
137	}
138
139
140
141	#if BYTE_ORDER == LITTLE_ENDIAN
142	#define le16_to_cpu(val) (val)
143	#define le32_to_cpu(val) (val)
144	#endif
145	#if BYTE_ORDER == BIG_ENDIAN
146	#define le16_to_cpu(val) bswap_16(val)
147	#define le32_to_cpu(val) bswap_32(val)
148	#endif
149
150	static uint16_t elf16_to_cpu(uint16_t val)
151	{
152	return le16_to_cpu(val);
153	}
154
155	static uint32_t elf32_to_cpu(uint32_t val)
156	{
157	return le32_to_cpu(val);
158	}
159
160	static void read_ehdr(FILE *fp)
161	{
162	if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
163	die("Cannot read ELF header: %s\n",
164	strerror(errno));
165	}
166	if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
167	die("No ELF magic\n");
168	}
169	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
170	die("Not a 32 bit executable\n");
171	}
172	if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
173	die("Not a LSB ELF executable\n");
174	}
175	if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
176	die("Unknown ELF version\n");
177	}
178	/* Convert the fields to native endian */
179	ehdr.e_type = elf16_to_cpu(ehdr.e_type);
180	ehdr.e_machine = elf16_to_cpu(ehdr.e_machine);
181	ehdr.e_version = elf32_to_cpu(ehdr.e_version);
182	ehdr.e_entry = elf32_to_cpu(ehdr.e_entry);
183	ehdr.e_phoff = elf32_to_cpu(ehdr.e_phoff);
184	ehdr.e_shoff = elf32_to_cpu(ehdr.e_shoff);
185	ehdr.e_flags = elf32_to_cpu(ehdr.e_flags);
186	ehdr.e_ehsize = elf16_to_cpu(ehdr.e_ehsize);
187	ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
188	ehdr.e_phnum = elf16_to_cpu(ehdr.e_phnum);
189	ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
190	ehdr.e_shnum = elf16_to_cpu(ehdr.e_shnum);
191	ehdr.e_shstrndx = elf16_to_cpu(ehdr.e_shstrndx);
192
193	if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
194	die("Unsupported ELF header type\n");
195	}
196	if (ehdr.e_machine != EM_386) {
197	die("Not for x86\n");
198	}
199	if (ehdr.e_version != EV_CURRENT) {
200	die("Unknown ELF version\n");
201	}
202	if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
203	die("Bad Elf header size\n");
204	}
205	if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
206	die("Bad program header entry\n");
207	}
208	if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
209	die("Bad section header entry\n");
210	}
211	if (ehdr.e_shstrndx >= ehdr.e_shnum) {
212	die("String table index out of bounds\n");
213	}
214	}
215
216	static void read_shdrs(FILE *fp)
217	{
218	int i;
219	if (ehdr.e_shnum > MAX_SHDRS) {
220	die("%d section headers supported: %d\n",
221	ehdr.e_shnum, MAX_SHDRS);
222	}
223	if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
224	die("Seek to %d failed: %s\n",
225	ehdr.e_shoff, strerror(errno));
226	}
227	if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
228	die("Cannot read ELF section headers: %s\n",
229	strerror(errno));
230	}
231	for(i = 0; i < ehdr.e_shnum; i++) {
232	shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
233	shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
234	shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
235	shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
236	shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
237	shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
238	shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
239	shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
240	shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
241	shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
242	}
243
244	}
245
246	static void read_strtabs(FILE *fp)
247	{
248	int i;
249	for(i = 0; i < ehdr.e_shnum; i++) {
250	if (shdr[i].sh_type != SHT_STRTAB) {
251	continue;
252	}
253	strtab[i] = malloc(shdr[i].sh_size);
254	if (!strtab[i]) {
255	die("malloc of %d bytes for strtab failed\n",
256	shdr[i].sh_size);
257	}
258	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
259	die("Seek to %d failed: %s\n",
260	shdr[i].sh_offset, strerror(errno));
261	}
262	if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
263	die("Cannot read symbol table: %s\n",
264	strerror(errno));
265	}
266	}
267	}
268
269	static void read_symtabs(FILE *fp)
270	{
271	int i,j;
272	for(i = 0; i < ehdr.e_shnum; i++) {
273	if (shdr[i].sh_type != SHT_SYMTAB) {
274	continue;
275	}
276	symtab[i] = malloc(shdr[i].sh_size);
277	if (!symtab[i]) {
278	die("malloc of %d bytes for symtab failed\n",
279	shdr[i].sh_size);
280	}
281	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
282	die("Seek to %d failed: %s\n",
283	shdr[i].sh_offset, strerror(errno));
284	}
285	if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
286	die("Cannot read symbol table: %s\n",
287	strerror(errno));
288	}
289	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
290	symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
291	symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
292	symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
293	symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
294	}
295	}
296	}
297
298
299	static void read_relocs(FILE *fp)
300	{
301	int i,j;
302	for(i = 0; i < ehdr.e_shnum; i++) {
303	if (shdr[i].sh_type != SHT_REL) {
304	continue;
305	}
306	reltab[i] = malloc(shdr[i].sh_size);
307	if (!reltab[i]) {
308	die("malloc of %d bytes for relocs failed\n",
309	shdr[i].sh_size);
310	}
311	if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
312	die("Seek to %d failed: %s\n",
313	shdr[i].sh_offset, strerror(errno));
314	}
315	if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
316	die("Cannot read symbol table: %s\n",
317	strerror(errno));
318	}
319	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
320	reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
321	reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
322	}
323	}
324	}
325
326
327	static void print_absolute_symbols(void)
328	{
329	int i;
330	printf("Absolute symbols\n");
331	printf(" Num: Value Size Type Bind Visibility Name\n");
332	for(i = 0; i < ehdr.e_shnum; i++) {
333	char *sym_strtab;
334	Elf32_Sym *sh_symtab;
335	int j;
336	if (shdr[i].sh_type != SHT_SYMTAB) {
337	continue;
338	}
339	sh_symtab = symtab[i];
340	sym_strtab = strtab[shdr[i].sh_link];
341	for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
342	Elf32_Sym *sym;
343	const char *name;
344	sym = &symtab[i][j];
345	name = sym_name(sym_strtab, sym);
346	if (sym->st_shndx != SHN_ABS) {
347	continue;
348	}
349	printf("%5d %08x %5d %10s %10s %12s %s\n",
350	j, sym->st_value, sym->st_size,
351	sym_type(ELF32_ST_TYPE(sym->st_info)),
352	sym_bind(ELF32_ST_BIND(sym->st_info)),
353	sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
354	name);
355	}
356	}
357	printf("\n");
358	}
359
360	static void print_absolute_relocs(void)
361	{
362	int i;
363	printf("Absolute relocations\n");
364	printf("Offset Info Type Sym.Value Sym.Name\n");
365	for(i = 0; i < ehdr.e_shnum; i++) {
366	char *sym_strtab;
367	Elf32_Sym *sh_symtab;
368	unsigned sec_applies, sec_symtab;
369	int j;
370	if (shdr[i].sh_type != SHT_REL) {
371	continue;
372	}
373	sec_symtab = shdr[i].sh_link;
374	sec_applies = shdr[i].sh_info;
375	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
376	continue;
377	}
378	sh_symtab = symtab[sec_symtab];
379	sym_strtab = strtab[shdr[sec_symtab].sh_link];
380	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
381	Elf32_Rel *rel;
382	Elf32_Sym *sym;
383	const char *name;
384	rel = &reltab[i][j];
385	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
386	name = sym_name(sym_strtab, sym);
387	if (sym->st_shndx != SHN_ABS) {
388	continue;
389	}
390	printf("%08x %08x %10s %08x %s\n",
391	rel->r_offset,
392	rel->r_info,
393	rel_type(ELF32_R_TYPE(rel->r_info)),
394	sym->st_value,
395	name);
396	}
397	}
398	printf("\n");
399	}
400
401	static void walk_relocs(void (visit)(Elf32_Rel rel, Elf32_Sym *sym))
402	{
403	int i;
404	/* Walk through the relocations */
405	for(i = 0; i < ehdr.e_shnum; i++) {
406	char *sym_strtab;
407	Elf32_Sym *sh_symtab;
408	unsigned sec_applies, sec_symtab;
409	int j;
410	if (shdr[i].sh_type != SHT_REL) {
411	continue;
412	}
413	sec_symtab = shdr[i].sh_link;
414	sec_applies = shdr[i].sh_info;
415	if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
416	continue;
417	}
418	sh_symtab = symtab[sec_symtab];
419	sym_strtab = strtab[shdr[sec_symtab].sh_link];
420	for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
421	Elf32_Rel *rel;
422	Elf32_Sym *sym;
423	unsigned r_type;
424	rel = &reltab[i][j];
425	sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
426	r_type = ELF32_R_TYPE(rel->r_info);
427	/* Don't visit relocations to absolute symbols */
428	if (sym->st_shndx == SHN_ABS) {
429	continue;
430	}
431	if (r_type == R_386_PC32) {
432	/* PC relative relocations don't need to be adjusted */
433	}
434	else if (r_type == R_386_32) {
435	/* Visit relocations that need to be adjusted */
436	visit(rel, sym);
437	}
438	else {
439	die("Unsupported relocation type: %d\n", r_type);
440	}
441	}
442	}
443	}
444
445	static void count_reloc(Elf32_Rel rel, Elf32_Sym sym)
446	{
447	reloc_count += 1;
448	}
449
450	static void collect_reloc(Elf32_Rel rel, Elf32_Sym sym)
451	{
452	/* Remember the address that needs to be adjusted. */
453	relocs[reloc_idx++] = rel->r_offset;
454	}
455
456	static int cmp_relocs(const void va, const void vb)
457	{
458	const unsigned long a, b;
459	a = va; b = vb;
460	return (a == b)? 0 : (a > b)? 1 : -1;
461	}
462
463	static void emit_relocs(int as_text)
464	{
465	int i;
466	/* Count how many relocations I have and allocate space for them. */
467	reloc_count = 0;
468	walk_relocs(count_reloc);
469	relocs = malloc(reloc_count * sizeof(relocs[0]));
470	if (!relocs) {
471	die("malloc of %d entries for relocs failed\n",
472	reloc_count);
473	}
474	/* Collect up the relocations */
475	reloc_idx = 0;
476	walk_relocs(collect_reloc);
477
478	/* Order the relocations for more efficient processing */
479	qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
480
481	/* Print the relocations */
482	if (as_text) {
483	/* Print the relocations in a form suitable that
484	* gas will like.
485	*/
486	printf(".section \".data.reloc\",\"a\"\n");
487	printf(".balign 4\n");
488	for(i = 0; i < reloc_count; i++) {
489	printf("\t .long 0x%08lx\n", relocs[i]);
490	}
491	printf("\n");
492	}
493	else {
494	unsigned char buf[4];
495	buf[0] = buf[1] = buf[2] = buf[3] = 0;
496	/* Print a stop */
497	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
498	/* Now print each relocation */
499	for(i = 0; i < reloc_count; i++) {
500	buf[0] = (relocs[i] >> 0) & 0xff;
501	buf[1] = (relocs[i] >> 8) & 0xff;
502	buf[2] = (relocs[i] >> 16) & 0xff;
503	buf[3] = (relocs[i] >> 24) & 0xff;
504	printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
505	}
506	}
507	}
508
509	static void usage(void)
510	{
511	die("i386_reloc [--abs \| --text] vmlinux\n");
512	}
513
514	int main(int argc, char **argv)
515	{
516	int show_absolute;
517	int as_text;
518	const char *fname;
519	FILE *fp;
520	int i;
521
522	show_absolute = 0;
523	as_text = 0;
524	fname = NULL;
525	for(i = 1; i < argc; i++) {
526	char *arg = argv[i];
527	if (*arg == '-') {
528	if (strcmp(argv[1], "--abs") == 0) {
529	show_absolute = 1;
530	continue;
531	}
532	else if (strcmp(argv[1], "--text") == 0) {
533	as_text = 1;
534	continue;
535	}
536	}
537	else if (!fname) {
538	fname = arg;
539	continue;
540	}
541	usage();
542	}
543	if (!fname) {
544	usage();
545	}
546	fp = fopen(fname, "r");
547	if (!fp) {
548	die("Cannot open %s: %s\n",
549	fname, strerror(errno));
550	}
551	read_ehdr(fp);
552	read_shdrs(fp);
553	read_strtabs(fp);
554	read_symtabs(fp);
555	read_relocs(fp);
556	if (show_absolute) {
557	print_absolute_symbols();
558	print_absolute_relocs();
559	return 0;
560	}
561	emit_relocs(as_text);
562	return 0;
563	}