1 a84cbb2a 2004-04-19 devnull /*
  2 a84cbb2a 2004-04-19 devnull  * Parse 32-bit ELF files.
  3 a84cbb2a 2004-04-19 devnull  * Copyright (c) 2004 Russ Cox.  See LICENSE.
  4 a84cbb2a 2004-04-19 devnull  */
  5 a84cbb2a 2004-04-19 devnull 
  6 a84cbb2a 2004-04-19 devnull #include <u.h>
  7 a84cbb2a 2004-04-19 devnull #include <libc.h>
  8 a84cbb2a 2004-04-19 devnull #include <mach.h>
  9 a84cbb2a 2004-04-19 devnull #include "elf.h"
 10 a84cbb2a 2004-04-19 devnull 
 11 a84cbb2a 2004-04-19 devnull typedef struct ElfHdrBytes ElfHdrBytes;
 12 a84cbb2a 2004-04-19 devnull typedef struct ElfSectBytes ElfSectBytes;
 13 a84cbb2a 2004-04-19 devnull typedef struct ElfProgBytes ElfProgBytes;
 14 a84cbb2a 2004-04-19 devnull typedef struct ElfSymBytes ElfSymBytes;
 15 a84cbb2a 2004-04-19 devnull 
 16 a84cbb2a 2004-04-19 devnull struct ElfHdrBytes
 17 a84cbb2a 2004-04-19 devnull {
 18 a84cbb2a 2004-04-19 devnull 	uchar	ident[16];
 19 a84cbb2a 2004-04-19 devnull 	uchar	type[2];
 20 a84cbb2a 2004-04-19 devnull 	uchar	machine[2];
 21 a84cbb2a 2004-04-19 devnull 	uchar	version[4];
 22 a84cbb2a 2004-04-19 devnull 	uchar	entry[4];
 23 a84cbb2a 2004-04-19 devnull 	uchar	phoff[4];
 24 a84cbb2a 2004-04-19 devnull 	uchar	shoff[4];
 25 a84cbb2a 2004-04-19 devnull 	uchar	flags[4];
 26 a84cbb2a 2004-04-19 devnull 	uchar	ehsize[2];
 27 a84cbb2a 2004-04-19 devnull 	uchar	phentsize[2];
 28 a84cbb2a 2004-04-19 devnull 	uchar	phnum[2];
 29 a84cbb2a 2004-04-19 devnull 	uchar	shentsize[2];
 30 a84cbb2a 2004-04-19 devnull 	uchar	shnum[2];
 31 a84cbb2a 2004-04-19 devnull 	uchar	shstrndx[2];
 32 a84cbb2a 2004-04-19 devnull };
 33 a84cbb2a 2004-04-19 devnull 
 34 a84cbb2a 2004-04-19 devnull struct ElfSectBytes
 35 a84cbb2a 2004-04-19 devnull {
 36 a84cbb2a 2004-04-19 devnull 	uchar	name[4];
 37 a84cbb2a 2004-04-19 devnull 	uchar	type[4];
 38 a84cbb2a 2004-04-19 devnull 	uchar	flags[4];
 39 a84cbb2a 2004-04-19 devnull 	uchar	addr[4];
 40 a84cbb2a 2004-04-19 devnull 	uchar	offset[4];
 41 a84cbb2a 2004-04-19 devnull 	uchar	size[4];
 42 a84cbb2a 2004-04-19 devnull 	uchar	link[4];
 43 a84cbb2a 2004-04-19 devnull 	uchar	info[4];
 44 a84cbb2a 2004-04-19 devnull 	uchar	align[4];
 45 a84cbb2a 2004-04-19 devnull 	uchar	entsize[4];
 46 a84cbb2a 2004-04-19 devnull };
 47 a84cbb2a 2004-04-19 devnull 
 48 a84cbb2a 2004-04-19 devnull struct ElfSymBytes
 49 a84cbb2a 2004-04-19 devnull {
 50 a84cbb2a 2004-04-19 devnull 	uchar	name[4];
 51 a84cbb2a 2004-04-19 devnull 	uchar	value[4];
 52 a84cbb2a 2004-04-19 devnull 	uchar	size[4];
 53 a84cbb2a 2004-04-19 devnull 	uchar	info;	/* top4: bind, bottom4: type */
 54 a84cbb2a 2004-04-19 devnull 	uchar	other;
 55 a84cbb2a 2004-04-19 devnull 	uchar	shndx[2];
 56 a84cbb2a 2004-04-19 devnull };
 57 a84cbb2a 2004-04-19 devnull 
 58 a84cbb2a 2004-04-19 devnull struct ElfProgBytes
 59 a84cbb2a 2004-04-19 devnull {
 60 a84cbb2a 2004-04-19 devnull 	uchar	type[4];
 61 a84cbb2a 2004-04-19 devnull 	uchar	offset[4];
 62 a84cbb2a 2004-04-19 devnull 	uchar	vaddr[4];
 63 a84cbb2a 2004-04-19 devnull 	uchar	paddr[4];
 64 a84cbb2a 2004-04-19 devnull 	uchar	filesz[4];
 65 a84cbb2a 2004-04-19 devnull 	uchar	memsz[4];
 66 a84cbb2a 2004-04-19 devnull 	uchar	flags[4];
 67 a84cbb2a 2004-04-19 devnull 	uchar	align[4];
 68 a84cbb2a 2004-04-19 devnull };
 69 a84cbb2a 2004-04-19 devnull 
 70 a84cbb2a 2004-04-19 devnull uchar ElfMagic[4] = { 0x7F, 'E', 'L', 'F' };
 71 a84cbb2a 2004-04-19 devnull 
 72 a84cbb2a 2004-04-19 devnull static void	unpackhdr(ElfHdr*, ElfHdrBytes*);
 73 a84cbb2a 2004-04-19 devnull static void	unpackprog(ElfHdr*, ElfProg*, ElfProgBytes*);
 74 a84cbb2a 2004-04-19 devnull static void	unpacksect(ElfHdr*, ElfSect*, ElfSectBytes*);
 75 a84cbb2a 2004-04-19 devnull 
 76 a84cbb2a 2004-04-19 devnull static char *elftypes[] = {
 77 a84cbb2a 2004-04-19 devnull 	"none",
 78 a84cbb2a 2004-04-19 devnull 	"relocatable",
 79 a84cbb2a 2004-04-19 devnull 	"executable",
 80 a84cbb2a 2004-04-19 devnull 	"shared object",
 81 a84cbb2a 2004-04-19 devnull 	"core",
 82 a84cbb2a 2004-04-19 devnull };
 83 a84cbb2a 2004-04-19 devnull 
 84 a84cbb2a 2004-04-19 devnull char*
 85 a84cbb2a 2004-04-19 devnull elftype(int t)
 86 a84cbb2a 2004-04-19 devnull {
 87 a84cbb2a 2004-04-19 devnull 	if(t < 0 || t >= nelem(elftypes))
 88 a84cbb2a 2004-04-19 devnull 		return "unknown";
 89 a84cbb2a 2004-04-19 devnull 	return elftypes[t];
 90 a84cbb2a 2004-04-19 devnull }
 91 a84cbb2a 2004-04-19 devnull 
 92 a84cbb2a 2004-04-19 devnull static char *elfmachs[] = {
 93 a84cbb2a 2004-04-19 devnull 	"none",
 94 a84cbb2a 2004-04-19 devnull 	"32100",
 95 a84cbb2a 2004-04-19 devnull 	"sparc",
 96 a84cbb2a 2004-04-19 devnull 	"386",
 97 a84cbb2a 2004-04-19 devnull 	"68000",
 98 a84cbb2a 2004-04-19 devnull 	"88000",
 99 a84cbb2a 2004-04-19 devnull 	"486",
100 a84cbb2a 2004-04-19 devnull 	"860",
101 a84cbb2a 2004-04-19 devnull 	"MIPS",
102 a84cbb2a 2004-04-19 devnull };
103 a84cbb2a 2004-04-19 devnull 
104 a84cbb2a 2004-04-19 devnull char*
105 a84cbb2a 2004-04-19 devnull elfmachine(int t)
106 a84cbb2a 2004-04-19 devnull {
107 a84cbb2a 2004-04-19 devnull 	if(t < 0 || t >= nelem(elfmachs))
108 a84cbb2a 2004-04-19 devnull 		return "unknown";
109 a84cbb2a 2004-04-19 devnull 	return elfmachs[t];
110 a84cbb2a 2004-04-19 devnull }
111 a84cbb2a 2004-04-19 devnull 
112 a84cbb2a 2004-04-19 devnull Elf*
113 a84cbb2a 2004-04-19 devnull elfopen(char *name)
114 a84cbb2a 2004-04-19 devnull {
115 a84cbb2a 2004-04-19 devnull 	int fd;
116 a84cbb2a 2004-04-19 devnull 	Elf *e;
117 a84cbb2a 2004-04-19 devnull 
118 a84cbb2a 2004-04-19 devnull 	if((fd = open(name, OREAD)) < 0)
119 a84cbb2a 2004-04-19 devnull 		return nil;
120 a84cbb2a 2004-04-19 devnull 	if((e = elfinit(fd)) == nil)
121 a84cbb2a 2004-04-19 devnull 		close(fd);
122 a84cbb2a 2004-04-19 devnull 	return e;
123 a84cbb2a 2004-04-19 devnull }
124 a84cbb2a 2004-04-19 devnull 
125 a84cbb2a 2004-04-19 devnull Elf*
126 a84cbb2a 2004-04-19 devnull elfinit(int fd)
127 a84cbb2a 2004-04-19 devnull {
128 a84cbb2a 2004-04-19 devnull 	int i;
129 a84cbb2a 2004-04-19 devnull 	Elf *e;
130 a84cbb2a 2004-04-19 devnull 	ElfHdr *h;
131 a84cbb2a 2004-04-19 devnull 	ElfHdrBytes hdrb;
132 a84cbb2a 2004-04-19 devnull 	ElfProgBytes progb;
133 a84cbb2a 2004-04-19 devnull 	ElfSectBytes sectb;
134 a84cbb2a 2004-04-19 devnull 	ElfSect *s;
135 a84cbb2a 2004-04-19 devnull 
136 a84cbb2a 2004-04-19 devnull 	e = mallocz(sizeof(Elf), 1);
137 a84cbb2a 2004-04-19 devnull 	if(e == nil)
138 a84cbb2a 2004-04-19 devnull 		return nil;
139 a84cbb2a 2004-04-19 devnull 	e->fd = fd;
140 a84cbb2a 2004-04-19 devnull 
141 a84cbb2a 2004-04-19 devnull 	/*
142 a84cbb2a 2004-04-19 devnull 	 * parse header
143 a84cbb2a 2004-04-19 devnull 	 */
144 a84cbb2a 2004-04-19 devnull 	seek(fd, 0, 0);
145 a84cbb2a 2004-04-19 devnull 	if(readn(fd, &hdrb, sizeof hdrb) != sizeof hdrb)
146 a84cbb2a 2004-04-19 devnull 		goto err;
147 a84cbb2a 2004-04-19 devnull 	h = &e->hdr;
148 a84cbb2a 2004-04-19 devnull 	unpackhdr(h, &hdrb);
149 a84cbb2a 2004-04-19 devnull 	if(h->class != ElfClass32){
150 a84cbb2a 2004-04-19 devnull 		werrstr("bad ELF class - not 32-bit");
151 a84cbb2a 2004-04-19 devnull 		goto err;
152 a84cbb2a 2004-04-19 devnull 	}
153 a84cbb2a 2004-04-19 devnull 	if(h->encoding != ElfDataLsb && h->encoding != ElfDataMsb){
154 a84cbb2a 2004-04-19 devnull 		werrstr("bad ELF encoding - not LSB, MSB");
155 a84cbb2a 2004-04-19 devnull 		goto err;
156 a84cbb2a 2004-04-19 devnull 	}
157 a84cbb2a 2004-04-19 devnull 	if(hdrb.ident[6] != h->version){
158 a84cbb2a 2004-04-19 devnull 		werrstr("bad ELF encoding - version mismatch %02ux and %08ux",
159 a84cbb2a 2004-04-19 devnull 			(uint)hdrb.ident[6], (uint)h->version);
160 a84cbb2a 2004-04-19 devnull 		goto err;
161 a84cbb2a 2004-04-19 devnull 	}
162 a84cbb2a 2004-04-19 devnull 
163 a84cbb2a 2004-04-19 devnull 	/*
164 a84cbb2a 2004-04-19 devnull 	 * the prog+section info is almost always small - just load it into memory.
165 a84cbb2a 2004-04-19 devnull 	 */
166 a84cbb2a 2004-04-19 devnull 	e->nprog = h->phnum;
167 a84cbb2a 2004-04-19 devnull 	e->prog = mallocz(sizeof(ElfProg)*e->nprog, 1);
168 a84cbb2a 2004-04-19 devnull 	for(i=0; i<e->nprog; i++){
169 a84cbb2a 2004-04-19 devnull 		if(seek(fd, h->phoff+i*h->phentsize, 0) < 0
170 a84cbb2a 2004-04-19 devnull 		|| readn(fd, &progb, sizeof progb) != sizeof progb)
171 a84cbb2a 2004-04-19 devnull 			goto err;
172 a84cbb2a 2004-04-19 devnull 		unpackprog(h, &e->prog[i], &progb);
173 a84cbb2a 2004-04-19 devnull 	}
174 a84cbb2a 2004-04-19 devnull 
175 a84cbb2a 2004-04-19 devnull 	e->nsect = h->shnum;
176 a84cbb2a 2004-04-19 devnull 	if(e->nsect == 0)
177 a84cbb2a 2004-04-19 devnull 		goto nosects;
178 a84cbb2a 2004-04-19 devnull 	e->sect = mallocz(sizeof(ElfSect)*e->nsect, 1);
179 a84cbb2a 2004-04-19 devnull 	for(i=0; i<e->nsect; i++){
180 a84cbb2a 2004-04-19 devnull 		if(seek(fd, h->shoff+i*h->shentsize, 0) < 0
181 a84cbb2a 2004-04-19 devnull 		|| readn(fd, &sectb, sizeof sectb) != sizeof sectb)
182 a84cbb2a 2004-04-19 devnull 			goto err;
183 a84cbb2a 2004-04-19 devnull 		unpacksect(h, &e->sect[i], &sectb);
184 a84cbb2a 2004-04-19 devnull 	}
185 a84cbb2a 2004-04-19 devnull 
186 a84cbb2a 2004-04-19 devnull 	if(h->shstrndx >= e->nsect){
187 a84cbb2a 2004-04-19 devnull 		fprint(2, "warning: bad string section index %d >= %d", h->shstrndx, e->nsect);
188 a84cbb2a 2004-04-19 devnull 		h->shnum = 0;
189 a84cbb2a 2004-04-19 devnull 		e->nsect = 0;
190 a84cbb2a 2004-04-19 devnull 		goto nosects;
191 a84cbb2a 2004-04-19 devnull 	}
192 a84cbb2a 2004-04-19 devnull 	s = &e->sect[h->shstrndx];
193 a84cbb2a 2004-04-19 devnull 	if(elfmap(e, s) < 0)
194 a84cbb2a 2004-04-19 devnull 		goto err;
195 a84cbb2a 2004-04-19 devnull 
196 a84cbb2a 2004-04-19 devnull 	for(i=0; i<e->nsect; i++)
197 a84cbb2a 2004-04-19 devnull 		if(e->sect[i].name)
198 929ba9b9 2004-04-20 devnull 			e->sect[i].name = (char*)s->base + (ulong)e->sect[i].name;
199 a84cbb2a 2004-04-19 devnull 
200 a84cbb2a 2004-04-19 devnull 	e->symtab = elfsection(e, ".symtab");
201 a84cbb2a 2004-04-19 devnull 	if(e->symtab){
202 a84cbb2a 2004-04-19 devnull 		if(e->symtab->link >= e->nsect)
203 a84cbb2a 2004-04-19 devnull 			e->symtab = nil;
204 a84cbb2a 2004-04-19 devnull 		else{
205 a84cbb2a 2004-04-19 devnull 			e->symstr = &e->sect[e->symtab->link];
206 a84cbb2a 2004-04-19 devnull 			e->nsymtab = e->symtab->size / sizeof(ElfSymBytes);
207 a84cbb2a 2004-04-19 devnull 		}
208 a84cbb2a 2004-04-19 devnull 	}
209 a84cbb2a 2004-04-19 devnull 	e->dynsym = elfsection(e, ".dynsym");
210 a84cbb2a 2004-04-19 devnull 	if(e->dynsym){
211 a84cbb2a 2004-04-19 devnull 		if(e->dynsym->link >= e->nsect)
212 a84cbb2a 2004-04-19 devnull 			e->dynsym = nil;
213 a84cbb2a 2004-04-19 devnull 		else{
214 a84cbb2a 2004-04-19 devnull 			e->dynstr = &e->sect[e->dynsym->link];
215 a84cbb2a 2004-04-19 devnull 			e->ndynsym = e->dynsym->size / sizeof(ElfSymBytes);
216 a84cbb2a 2004-04-19 devnull 		}
217 a84cbb2a 2004-04-19 devnull 	}
218 a84cbb2a 2004-04-19 devnull 
219 a84cbb2a 2004-04-19 devnull 	e->bss = elfsection(e, ".bss");
220 a84cbb2a 2004-04-19 devnull 
221 a84cbb2a 2004-04-19 devnull nosects:
222 a84cbb2a 2004-04-19 devnull 	return e;
223 a84cbb2a 2004-04-19 devnull 
224 a84cbb2a 2004-04-19 devnull err:
225 a84cbb2a 2004-04-19 devnull 	free(e->sect);
226 a84cbb2a 2004-04-19 devnull 	free(e->prog);
227 a84cbb2a 2004-04-19 devnull 	free(e->shstrtab);
228 a84cbb2a 2004-04-19 devnull 	free(e);
229 a84cbb2a 2004-04-19 devnull 	return nil;
230 a84cbb2a 2004-04-19 devnull }
231 a84cbb2a 2004-04-19 devnull 
232 a84cbb2a 2004-04-19 devnull void
233 a84cbb2a 2004-04-19 devnull elfclose(Elf *elf)
234 a84cbb2a 2004-04-19 devnull {
235 a84cbb2a 2004-04-19 devnull 	int i;
236 a84cbb2a 2004-04-19 devnull 
237 a84cbb2a 2004-04-19 devnull 	for(i=0; i<elf->nsect; i++)
238 a84cbb2a 2004-04-19 devnull 		free(elf->sect[i].base);
239 a84cbb2a 2004-04-19 devnull 	free(elf->sect);
240 a84cbb2a 2004-04-19 devnull 	free(elf->prog);
241 a84cbb2a 2004-04-19 devnull 	free(elf->shstrtab);
242 a84cbb2a 2004-04-19 devnull 	free(elf);
243 a84cbb2a 2004-04-19 devnull }
244 a84cbb2a 2004-04-19 devnull 
245 a84cbb2a 2004-04-19 devnull static void
246 a84cbb2a 2004-04-19 devnull unpackhdr(ElfHdr *h, ElfHdrBytes *b)
247 a84cbb2a 2004-04-19 devnull {
248 a84cbb2a 2004-04-19 devnull 	u16int (*e2)(uchar*);
249 a84cbb2a 2004-04-19 devnull 	u32int (*e4)(uchar*);
250 a84cbb2a 2004-04-19 devnull 	u64int (*e8)(uchar*);
251 a84cbb2a 2004-04-19 devnull 
252 a84cbb2a 2004-04-19 devnull 	memmove(h->magic, b->ident, 4);
253 a84cbb2a 2004-04-19 devnull 	h->class = b->ident[4];
254 a84cbb2a 2004-04-19 devnull 	h->encoding = b->ident[5];
255 a84cbb2a 2004-04-19 devnull 	switch(h->encoding){
256 a84cbb2a 2004-04-19 devnull 	case ElfDataLsb:
257 a84cbb2a 2004-04-19 devnull 		e2 = leload2;
258 a84cbb2a 2004-04-19 devnull 		e4 = leload4;
259 a84cbb2a 2004-04-19 devnull 		e8 = leload8;
260 a84cbb2a 2004-04-19 devnull 		break;
261 a84cbb2a 2004-04-19 devnull 	case ElfDataMsb:
262 a84cbb2a 2004-04-19 devnull 		e2 = beload2;
263 a84cbb2a 2004-04-19 devnull 		e4 = beload4;
264 a84cbb2a 2004-04-19 devnull 		e8 = beload8;
265 a84cbb2a 2004-04-19 devnull 		break;
266 a84cbb2a 2004-04-19 devnull 	default:
267 a84cbb2a 2004-04-19 devnull 		return;
268 a84cbb2a 2004-04-19 devnull 	}
269 a84cbb2a 2004-04-19 devnull 	h->abi = b->ident[7];
270 a84cbb2a 2004-04-19 devnull 	h->abiversion = b->ident[8];
271 a84cbb2a 2004-04-19 devnull 
272 a84cbb2a 2004-04-19 devnull 	h->e2 = e2;
273 a84cbb2a 2004-04-19 devnull 	h->e4 = e4;
274 a84cbb2a 2004-04-19 devnull 	h->e8 = e8;
275 a84cbb2a 2004-04-19 devnull 	
276 a84cbb2a 2004-04-19 devnull 	h->type = e2(b->type);
277 a84cbb2a 2004-04-19 devnull 	h->machine = e2(b->machine);
278 a84cbb2a 2004-04-19 devnull 	h->version = e4(b->version);
279 a84cbb2a 2004-04-19 devnull 	h->entry = e4(b->entry);
280 a84cbb2a 2004-04-19 devnull 	h->phoff = e4(b->phoff);
281 a84cbb2a 2004-04-19 devnull 	h->shoff = e4(b->shoff);
282 a84cbb2a 2004-04-19 devnull 	h->flags = e4(b->flags);
283 a84cbb2a 2004-04-19 devnull 	h->ehsize = e2(b->ehsize);
284 a84cbb2a 2004-04-19 devnull 	h->phentsize = e2(b->phentsize);
285 a84cbb2a 2004-04-19 devnull 	h->phnum = e2(b->phnum);
286 a84cbb2a 2004-04-19 devnull 	h->shentsize = e2(b->shentsize);
287 a84cbb2a 2004-04-19 devnull 	h->shnum = e2(b->shnum);
288 a84cbb2a 2004-04-19 devnull 	h->shstrndx = e2(b->shstrndx);
289 a84cbb2a 2004-04-19 devnull }
290 a84cbb2a 2004-04-19 devnull 
291 a84cbb2a 2004-04-19 devnull static void
292 a84cbb2a 2004-04-19 devnull unpackprog(ElfHdr *h, ElfProg *p, ElfProgBytes *b)
293 a84cbb2a 2004-04-19 devnull {
294 a84cbb2a 2004-04-19 devnull 	u32int (*e4)(uchar*);
295 a84cbb2a 2004-04-19 devnull 
296 a84cbb2a 2004-04-19 devnull 	e4 = h->e4;
297 a84cbb2a 2004-04-19 devnull 	p->type = e4(b->type);
298 a84cbb2a 2004-04-19 devnull 	p->offset = e4(b->offset);
299 a84cbb2a 2004-04-19 devnull 	p->vaddr = e4(b->vaddr);
300 a84cbb2a 2004-04-19 devnull 	p->paddr = e4(b->paddr);
301 a84cbb2a 2004-04-19 devnull 	p->filesz = e4(b->filesz);
302 a84cbb2a 2004-04-19 devnull 	p->memsz = e4(b->memsz);
303 a84cbb2a 2004-04-19 devnull 	p->flags = e4(b->flags);
304 a84cbb2a 2004-04-19 devnull 	p->align = e4(b->align);
305 a84cbb2a 2004-04-19 devnull }
306 a84cbb2a 2004-04-19 devnull 
307 a84cbb2a 2004-04-19 devnull static void
308 a84cbb2a 2004-04-19 devnull unpacksect(ElfHdr *h, ElfSect *s, ElfSectBytes *b)
309 a84cbb2a 2004-04-19 devnull {
310 a84cbb2a 2004-04-19 devnull 	u32int (*e4)(uchar*);
311 a84cbb2a 2004-04-19 devnull 
312 a84cbb2a 2004-04-19 devnull 	e4 = h->e4;
313 35afcc6c 2006-04-20 devnull 	s->name = (char*)(uintptr)e4(b->name);
314 a84cbb2a 2004-04-19 devnull 	s->type = e4(b->type);
315 a84cbb2a 2004-04-19 devnull 	s->flags = e4(b->flags);
316 a84cbb2a 2004-04-19 devnull 	s->addr = e4(b->addr);
317 a84cbb2a 2004-04-19 devnull 	s->offset = e4(b->offset);
318 a84cbb2a 2004-04-19 devnull 	s->size = e4(b->size);
319 a84cbb2a 2004-04-19 devnull 	s->link = e4(b->link);
320 a84cbb2a 2004-04-19 devnull 	s->info = e4(b->info);
321 a84cbb2a 2004-04-19 devnull 	s->align = e4(b->align);
322 a84cbb2a 2004-04-19 devnull 	s->entsize = e4(b->entsize);
323 a84cbb2a 2004-04-19 devnull }
324 a84cbb2a 2004-04-19 devnull 
325 a84cbb2a 2004-04-19 devnull ElfSect*
326 a84cbb2a 2004-04-19 devnull elfsection(Elf *elf, char *name)
327 a84cbb2a 2004-04-19 devnull {
328 a84cbb2a 2004-04-19 devnull 	int i;
329 a84cbb2a 2004-04-19 devnull 
330 a84cbb2a 2004-04-19 devnull 	for(i=0; i<elf->nsect; i++){
331 a84cbb2a 2004-04-19 devnull 		if(elf->sect[i].name == name)
332 a84cbb2a 2004-04-19 devnull 			return &elf->sect[i];
333 a84cbb2a 2004-04-19 devnull 		if(elf->sect[i].name && name
334 a84cbb2a 2004-04-19 devnull 		&& strcmp(elf->sect[i].name, name) == 0)
335 a84cbb2a 2004-04-19 devnull 			return &elf->sect[i];
336 a84cbb2a 2004-04-19 devnull 	}
337 a84cbb2a 2004-04-19 devnull 	werrstr("elf section '%s' not found", name);
338 a84cbb2a 2004-04-19 devnull 	return nil;
339 a84cbb2a 2004-04-19 devnull }
340 a84cbb2a 2004-04-19 devnull 
341 a84cbb2a 2004-04-19 devnull int
342 a84cbb2a 2004-04-19 devnull elfmap(Elf *elf, ElfSect *sect)
343 a84cbb2a 2004-04-19 devnull {
344 a84cbb2a 2004-04-19 devnull 	if(sect->base)
345 a84cbb2a 2004-04-19 devnull 		return 0;
346 a84cbb2a 2004-04-19 devnull 	if((sect->base = malloc(sect->size)) == nil)
347 a84cbb2a 2004-04-19 devnull 		return -1;
348 a84cbb2a 2004-04-19 devnull 	werrstr("short read");
349 a84cbb2a 2004-04-19 devnull 	if(seek(elf->fd, sect->offset, 0) < 0
350 a84cbb2a 2004-04-19 devnull 	|| readn(elf->fd, sect->base, sect->size) != sect->size){
351 a84cbb2a 2004-04-19 devnull 		free(sect->base);
352 a84cbb2a 2004-04-19 devnull 		sect->base = nil;
353 a84cbb2a 2004-04-19 devnull 		return -1;
354 a84cbb2a 2004-04-19 devnull 	}
355 a84cbb2a 2004-04-19 devnull 	return 0;
356 a84cbb2a 2004-04-19 devnull }
357 a84cbb2a 2004-04-19 devnull 
358 a84cbb2a 2004-04-19 devnull int
359 a84cbb2a 2004-04-19 devnull elfsym(Elf *elf, int i, ElfSym *sym)
360 a84cbb2a 2004-04-19 devnull {
361 a84cbb2a 2004-04-19 devnull 	ElfSect *symtab, *strtab;
362 a84cbb2a 2004-04-19 devnull 	uchar *p;
363 a84cbb2a 2004-04-19 devnull 	char *s;
364 a84cbb2a 2004-04-19 devnull 	ulong x;
365 a84cbb2a 2004-04-19 devnull 
366 a84cbb2a 2004-04-19 devnull 	if(i < 0){
367 a84cbb2a 2004-04-19 devnull 		werrstr("bad index %d in elfsym", i);
368 a84cbb2a 2004-04-19 devnull 		return -1;
369 a84cbb2a 2004-04-19 devnull 	}
370 a84cbb2a 2004-04-19 devnull 
371 a84cbb2a 2004-04-19 devnull 	if(i < elf->nsymtab){
372 a84cbb2a 2004-04-19 devnull 		symtab = elf->symtab;
373 a84cbb2a 2004-04-19 devnull 		strtab = elf->symstr;
374 a84cbb2a 2004-04-19 devnull 	extract:
375 a84cbb2a 2004-04-19 devnull 		if(elfmap(elf, symtab) < 0 || elfmap(elf, strtab) < 0)
376 a84cbb2a 2004-04-19 devnull 			return -1;
377 a84cbb2a 2004-04-19 devnull 		p = symtab->base + i * sizeof(ElfSymBytes);
378 929ba9b9 2004-04-20 devnull 		s = (char*)strtab->base;
379 a84cbb2a 2004-04-19 devnull 		x = elf->hdr.e4(p);
380 a84cbb2a 2004-04-19 devnull 		if(x >= strtab->size){
381 a84cbb2a 2004-04-19 devnull 			werrstr("bad symbol name offset 0x%lux", x);
382 a84cbb2a 2004-04-19 devnull 			return -1;
383 a84cbb2a 2004-04-19 devnull 		}
384 a84cbb2a 2004-04-19 devnull 		sym->name = s + x;
385 a84cbb2a 2004-04-19 devnull 		sym->value = elf->hdr.e4(p+4);
386 a84cbb2a 2004-04-19 devnull 		sym->size = elf->hdr.e4(p+8);
387 a84cbb2a 2004-04-19 devnull 		x = p[12];
388 a84cbb2a 2004-04-19 devnull 		sym->bind = x>>4;
389 a84cbb2a 2004-04-19 devnull 		sym->type = x & 0xF;
390 a84cbb2a 2004-04-19 devnull 		sym->other = p[13];
391 a84cbb2a 2004-04-19 devnull 		sym->shndx = elf->hdr.e2(p+14);
392 a84cbb2a 2004-04-19 devnull 		return 0;
393 a84cbb2a 2004-04-19 devnull 	}
394 a84cbb2a 2004-04-19 devnull 	i -= elf->nsymtab;
395 a84cbb2a 2004-04-19 devnull 	if(i < elf->ndynsym){
396 a84cbb2a 2004-04-19 devnull 		symtab = elf->dynsym;
397 a84cbb2a 2004-04-19 devnull 		strtab = elf->dynstr;
398 a84cbb2a 2004-04-19 devnull 		goto extract;
399 a84cbb2a 2004-04-19 devnull 	}
400 a84cbb2a 2004-04-19 devnull 	/* i -= elf->ndynsym */
401 a84cbb2a 2004-04-19 devnull 
402 a84cbb2a 2004-04-19 devnull 	werrstr("symbol index out of range");
403 a84cbb2a 2004-04-19 devnull 	return -1;
404 a84cbb2a 2004-04-19 devnull }
405 a84cbb2a 2004-04-19 devnull