2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org>
3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
34 #include <sys/linker.h>
35 #include <sys/module.h>
38 #include <machine/elf.h>
41 #include <sys/link_elf.h>
43 #include "bootstrap.h"
45 #define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
47 #if defined(__i386__) && __ELF_WORD_SIZE == 64
50 #define ELF_TARG_CLASS ELFCLASS64
51 #define ELF_TARG_MACH EM_X86_64
54 typedef struct elf_file {
58 int symtabindex; /* Index of symbol table */
59 int shstrindex; /* Index of section name string table */
65 static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
67 static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
68 const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
69 static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
70 Elf_Addr p, void *val, size_t len);
71 static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
73 static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
75 const char *__elfN(obj_kerneltype) = "elf kernel";
76 const char *__elfN(obj_moduletype) = "elf obj module";
79 * Attempt to load the file (file) as an ELF module. It will be stored at
80 * (dest), and a pointer to a module structure describing the loaded object
81 * will be saved in (result).
84 __elfN(obj_loadfile)(char *filename, uint64_t dest,
85 struct preloaded_file **result)
87 struct preloaded_file *fp, *kfp;
94 bzero(&ef, sizeof(struct elf_file));
97 * Open the image, read and validate the ELF header
99 if (filename == NULL) /* can't handle nameless */
101 if ((ef.fd = open(filename, O_RDONLY)) == -1)
105 bytes_read = read(ef.fd, hdr, sizeof(*hdr));
106 if (bytes_read != sizeof(*hdr)) {
107 err = EFTYPE; /* could be EIO, but may be small file */
116 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
117 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
118 hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
119 hdr->e_version != EV_CURRENT ||
120 hdr->e_machine != ELF_TARG_MACH || /* Machine ? */
121 hdr->e_type != ET_REL) {
126 if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
127 hdr->e_shentsize != sizeof(Elf_Shdr)) {
132 kfp = file_findfile(NULL, __elfN(obj_kerneltype));
134 printf("elf" __XSTRING(__ELF_WORD_SIZE)
135 "_obj_loadfile: can't load module before kernel\n");
140 if (archsw.arch_loadaddr != NULL)
141 dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
143 dest = roundup(dest, PAGE_SIZE);
146 * Ok, we think we should handle this.
150 printf("elf" __XSTRING(__ELF_WORD_SIZE)
151 "_obj_loadfile: cannot allocate module info\n");
155 fp->f_name = strdup(filename);
156 fp->f_type = strdup(__elfN(obj_moduletype));
158 printf("%s ", filename);
160 fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
161 if (fp->f_size == 0 || fp->f_addr == 0)
164 /* save exec header as metadata */
165 file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
167 /* Load OK, return module pointer */
168 *result = (struct preloaded_file *)fp;
178 if (ef.e_shdr != NULL)
185 * With the file (fd) open on the image, and (ehdr) containing
186 * the Elf header, load the image at (off)
189 __elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, uint64_t off)
192 Elf_Shdr *shdr, *cshdr, *lshdr;
193 vm_offset_t firstaddr, lastaddr;
194 int i, nsym, res, ret, shdrbytes, symstrindex;
197 firstaddr = lastaddr = (vm_offset_t)off;
199 ef->off = (vm_offset_t)off;
201 /* Read in the section headers. */
202 shdrbytes = hdr->e_shnum * hdr->e_shentsize;
203 shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
205 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
206 "_obj_loadimage: read section headers failed\n");
212 * Decide where to load everything, but don't read it yet.
213 * We store the load address as a non-zero sh_addr value.
214 * Start with the code/data and bss.
216 for (i = 0; i < hdr->e_shnum; i++)
218 for (i = 0; i < hdr->e_shnum; i++) {
219 if (shdr[i].sh_size == 0)
221 switch (shdr[i].sh_type) {
224 #if defined(__i386__) || defined(__amd64__)
225 case SHT_X86_64_UNWIND:
227 if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
229 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
230 shdr[i].sh_addr = (Elf_Addr)lastaddr;
231 lastaddr += shdr[i].sh_size;
238 for (i = 0; i < hdr->e_shnum; i++) {
239 switch (shdr[i].sh_type) {
243 shdr[i].sh_addr = (Elf_Addr)lastaddr;
244 lastaddr += shdr[i].sh_size;
249 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
250 "_obj_loadimage: file has no valid symbol table\n");
253 lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
254 shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
255 lastaddr += shdr[ef->symtabindex].sh_size;
257 symstrindex = shdr[ef->symtabindex].sh_link;
258 if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
259 shdr[symstrindex].sh_type != SHT_STRTAB) {
260 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
261 "_obj_loadimage: file has invalid symbol strings\n");
264 lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
265 shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
266 lastaddr += shdr[symstrindex].sh_size;
269 if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
270 shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
271 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
272 "_obj_loadimage: file has no section names\n");
275 ef->shstrindex = hdr->e_shstrndx;
276 lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
277 shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
278 lastaddr += shdr[ef->shstrindex].sh_size;
280 /* Relocation tables. */
281 for (i = 0; i < hdr->e_shnum; i++) {
282 switch (shdr[i].sh_type) {
285 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
287 lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
288 shdr[i].sh_addr = (Elf_Addr)lastaddr;
289 lastaddr += shdr[i].sh_size;
294 /* Clear the whole area, including bss regions. */
295 kern_bzero(firstaddr, lastaddr - firstaddr);
297 /* Figure section with the lowest file offset we haven't loaded yet. */
298 for (cshdr = NULL; /* none */; /* none */)
301 * Find next section to load. The complexity of this loop is
302 * O(n^2), but with the number of sections being typically
303 * small, we do not care.
307 for (i = 0; i < hdr->e_shnum; i++) {
308 if (shdr[i].sh_addr == 0 ||
309 shdr[i].sh_type == SHT_NOBITS)
311 /* Skip sections that were loaded already. */
313 lshdr->sh_offset >= shdr[i].sh_offset)
315 /* Find section with smallest offset. */
316 if (cshdr == lshdr ||
317 cshdr->sh_offset > shdr[i].sh_offset)
324 if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr,
325 cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
326 printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
327 "_obj_loadimage: read failed\n");
332 file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
334 res = __elfN(obj_parse_modmetadata)(fp, ef);
338 ret = lastaddr - firstaddr;
339 fp->f_addr = firstaddr;
341 printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
348 #if defined(__i386__) && __ELF_WORD_SIZE == 64
349 struct mod_metadata64 {
350 int md_version; /* structure version MDTV_* */
351 int md_type; /* type of entry MDT_* */
352 uint64_t md_data; /* specific data */
353 uint64_t md_cval; /* common string label */
358 __elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
360 struct mod_metadata md;
361 #if defined(__i386__) && __ELF_WORD_SIZE == 64
362 struct mod_metadata64 md64;
364 struct mod_depend *mdepend;
365 struct mod_version mver;
367 int error, modcnt, minfolen;
368 Elf_Addr v, p, p_stop;
370 if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
376 COPYOUT(p, &v, sizeof(v));
377 error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
380 #if defined(__i386__) && __ELF_WORD_SIZE == 64
381 COPYOUT(v, &md64, sizeof(md64));
382 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
385 md.md_version = md64.md_version;
386 md.md_type = md64.md_type;
387 md.md_cval = (const char *)(uintptr_t)md64.md_cval;
388 md.md_data = (void *)(uintptr_t)md64.md_data;
390 COPYOUT(v, &md, sizeof(md));
391 error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
395 p += sizeof(Elf_Addr);
398 s = strdupout((vm_offset_t)md.md_cval);
399 minfolen = sizeof(*mdepend) + strlen(s) + 1;
400 mdepend = malloc(minfolen);
403 COPYOUT((vm_offset_t)md.md_data, mdepend,
405 strcpy((char*)(mdepend + 1), s);
407 file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
412 s = strdupout((vm_offset_t)md.md_cval);
413 COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
414 file_addmodule(fp, s, mver.mv_version, NULL);
422 printf("unknown type %d\n", md.md_type);
430 __elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
431 const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
436 vm_offset_t shstrtab;
441 shstrtab = shdr[ef->shstrindex].sh_addr;
443 for (i = 0; i < hdr->e_shnum; i++) {
444 if (shdr[i].sh_type != SHT_PROGBITS)
446 if (shdr[i].sh_name == 0)
448 p = strdupout(shstrtab + shdr[i].sh_name);
449 if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
450 *startp = shdr[i].sh_addr;
451 *stopp = shdr[i].sh_addr + shdr[i].sh_size;
452 *countp = (*stopp - *startp) / sizeof(Elf_Addr);
463 * Apply any intra-module relocations to the value. p is the load address
464 * of the value and val/len is the value to be modified. This does NOT modify
465 * the image in-place, because this is done by kern_linker later on.
468 __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
469 void *val, size_t len)
477 int error, i, j, nrel, nrela;
482 for (i = 0; i < hdr->e_shnum; i++) {
483 if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
485 base = shdr[shdr[i].sh_info].sh_addr;
486 if (base == 0 || shdr[i].sh_addr == 0)
488 if (off < base || off + len > base +
489 shdr[shdr[i].sh_info].sh_size)
492 switch (shdr[i].sh_type) {
494 abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
496 nrela = shdr[i].sh_size / sizeof(Elf_Rela);
497 for (j = 0; j < nrela; j++) {
498 COPYOUT(abase + j, &a, sizeof(a));
500 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
501 &a, ELF_RELOC_RELA, base, off, val, len);
507 rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
509 nrel = shdr[i].sh_size / sizeof(Elf_Rel);
510 for (j = 0; j < nrel; j++) {
511 COPYOUT(rbase + j, &r, sizeof(r));
513 error = __elfN(reloc)(ef, __elfN(obj_symaddr),
514 &r, ELF_RELOC_REL, base, off, val, len);
524 /* Look up the address of a specified symbol. */
526 __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
531 if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
533 COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
535 if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
537 base = ef->e_shdr[sym.st_shndx].sh_addr;
540 return (base + sym.st_value);