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freebsd-nq/sys/boot/common/load_elf.c
Ian Lepore 7554e820bb Attach the elf section headers to the loaded kernel as metadata, so 
they can easily be used by later post-processing.  When searching for
a compiled-in fdt blob, use the section headers to get the size and
location of the .dynsym section to do a symbol search.

This fixes a problem where the search could overshoot the symbol
table and wander into the string table.  Sometimes that was harmless
and sometimes it lead to spurious panic messages about an offset
bigger than the module size.
2013-03-10 00:43:01 +00:00

805 lines
22 KiB
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/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/stdint.h>
#include <string.h>
#include <machine/elf.h>
#include <stand.h>
#define FREEBSD_ELF
#include <link.h>
#include "bootstrap.h"
#define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l)
#if defined(__i386__) && __ELF_WORD_SIZE == 64
#undef ELF_TARG_CLASS
#undef ELF_TARG_MACH
#define ELF_TARG_CLASS ELFCLASS64
#define ELF_TARG_MACH EM_X86_64
#endif
typedef struct elf_file {
Elf_Phdr *ph;
Elf_Ehdr *ehdr;
Elf_Sym *symtab;
Elf_Hashelt *hashtab;
Elf_Hashelt nbuckets;
Elf_Hashelt nchains;
Elf_Hashelt *buckets;
Elf_Hashelt *chains;
Elf_Rel *rel;
size_t relsz;
Elf_Rela *rela;
size_t relasz;
char *strtab;
size_t strsz;
int fd;
caddr_t firstpage;
size_t firstlen;
int kernel;
u_int64_t off;
} *elf_file_t;
static int __elfN(loadimage)(struct preloaded_file *mp, elf_file_t ef, u_int64_t loadaddr);
static int __elfN(lookup_symbol)(struct preloaded_file *mp, elf_file_t ef, const char* name, Elf_Sym* sym);
static int __elfN(reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
Elf_Addr p, void *val, size_t len);
static int __elfN(parse_modmetadata)(struct preloaded_file *mp, elf_file_t ef);
static symaddr_fn __elfN(symaddr);
static char *fake_modname(const char *name);
const char *__elfN(kerneltype) = "elf kernel";
const char *__elfN(moduletype) = "elf module";
u_int64_t __elfN(relocation_offset) = 0;
/*
* Attempt to load the file (file) as an ELF module. It will be stored at
* (dest), and a pointer to a module structure describing the loaded object
* will be saved in (result).
*/
int
__elfN(loadfile)(char *filename, u_int64_t dest, struct preloaded_file **result)
{
struct preloaded_file *fp, *kfp;
struct elf_file ef;
Elf_Ehdr *ehdr;
int err;
ssize_t bytes_read;
fp = NULL;
bzero(&ef, sizeof(struct elf_file));
/*
* Open the image, read and validate the ELF header
*/
if (filename == NULL) /* can't handle nameless */
return(EFTYPE);
if ((ef.fd = open(filename, O_RDONLY)) == -1)
return(errno);
ef.firstpage = malloc(PAGE_SIZE);
if (ef.firstpage == NULL) {
close(ef.fd);
return(ENOMEM);
}
bytes_read = read(ef.fd, ef.firstpage, PAGE_SIZE);
ef.firstlen = (size_t)bytes_read;
if (bytes_read < 0 || ef.firstlen <= sizeof(Elf_Ehdr)) {
err = EFTYPE; /* could be EIO, but may be small file */
goto oerr;
}
ehdr = ef.ehdr = (Elf_Ehdr *)ef.firstpage;
/* Is it ELF? */
if (!IS_ELF(*ehdr)) {
err = EFTYPE;
goto oerr;
}
if (ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */
ehdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
ehdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */
ehdr->e_version != EV_CURRENT ||
ehdr->e_machine != ELF_TARG_MACH) { /* Machine ? */
err = EFTYPE;
goto oerr;
}
/*
* Check to see what sort of module we are.
*/
kfp = file_findfile(NULL, NULL);
if (ehdr->e_type == ET_DYN) {
/* Looks like a kld module */
if (kfp == NULL) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadfile: can't load module before kernel\n");
err = EPERM;
goto oerr;
}
if (strcmp(__elfN(kerneltype), kfp->f_type)) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadfile: can't load module with kernel type '%s'\n", kfp->f_type);
err = EPERM;
goto oerr;
}
/* Looks OK, got ahead */
ef.kernel = 0;
} else if (ehdr->e_type == ET_EXEC) {
/* Looks like a kernel */
if (kfp != NULL) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadfile: kernel already loaded\n");
err = EPERM;
goto oerr;
}
/*
* Calculate destination address based on kernel entrypoint
*/
dest = (ehdr->e_entry & ~PAGE_MASK);
if (dest == 0) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadfile: not a kernel (maybe static binary?)\n");
err = EPERM;
goto oerr;
}
ef.kernel = 1;
} else {
err = EFTYPE;
goto oerr;
}
if (archsw.arch_loadaddr != NULL)
dest = archsw.arch_loadaddr(LOAD_ELF, ehdr, dest);
else
dest = roundup(dest, PAGE_SIZE);
/*
* Ok, we think we should handle this.
*/
fp = file_alloc();
if (fp == NULL) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadfile: cannot allocate module info\n");
err = EPERM;
goto out;
}
if (ef.kernel)
setenv("kernelname", filename, 1);
fp->f_name = strdup(filename);
fp->f_type = strdup(ef.kernel ? __elfN(kerneltype) : __elfN(moduletype));
#ifdef ELF_VERBOSE
if (ef.kernel)
printf("%s entry at 0x%jx\n", filename, (uintmax_t)ehdr->e_entry);
#else
printf("%s ", filename);
#endif
fp->f_size = __elfN(loadimage)(fp, &ef, dest);
if (fp->f_size == 0 || fp->f_addr == 0)
goto ioerr;
/* save exec header as metadata */
file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*ehdr), ehdr);
/* Load OK, return module pointer */
*result = (struct preloaded_file *)fp;
err = 0;
goto out;
ioerr:
err = EIO;
oerr:
file_discard(fp);
out:
if (ef.firstpage)
free(ef.firstpage);
close(ef.fd);
return(err);
}
/*
* With the file (fd) open on the image, and (ehdr) containing
* the Elf header, load the image at (off)
*/
static int
__elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
{
int i;
u_int j;
Elf_Ehdr *ehdr;
Elf_Phdr *phdr, *php;
Elf_Shdr *shdr;
int ret;
vm_offset_t firstaddr;
vm_offset_t lastaddr;
size_t chunk;
ssize_t result;
Elf_Addr ssym, esym;
Elf_Dyn *dp;
Elf_Addr adp;
int ndp;
int symstrindex;
int symtabindex;
Elf_Size size;
u_int fpcopy;
dp = NULL;
shdr = NULL;
ret = 0;
firstaddr = lastaddr = 0;
ehdr = ef->ehdr;
if (ef->kernel) {
#if defined(__i386__) || defined(__amd64__)
#if __ELF_WORD_SIZE == 64
off = - (off & 0xffffffffff000000ull);/* x86_64 relocates after locore */
#else
off = - (off & 0xff000000u); /* i386 relocates after locore */
#endif
#elif defined(__powerpc__)
/*
* On the purely virtual memory machines like e500, the kernel is
* linked against its final VA range, which is most often not
* available at the loader stage, but only after kernel initializes
* and completes its VM settings. In such cases we cannot use p_vaddr
* field directly to load ELF segments, but put them at some
* 'load-time' locations.
*/
if (off & 0xf0000000u) {
off = -(off & 0xf0000000u);
/*
* XXX the physical load address should not be hardcoded. Note
* that the Book-E kernel assumes that it's loaded at a 16MB
* boundary for now...
*/
off += 0x01000000;
ehdr->e_entry += off;
#ifdef ELF_VERBOSE
printf("Converted entry 0x%08x\n", ehdr->e_entry);
#endif
} else
off = 0;
#elif defined(__arm__)
/*
* The elf headers in some kernels specify virtual addresses in all
* header fields. More recently, the e_entry and p_paddr fields are the
* proper physical addresses. Even when the p_paddr fields are correct,
* the MI code below uses the p_vaddr fields with an offset added for
* loading (doing so is arguably wrong). To make loading work, we need
* an offset that represents the difference between physical and virtual
* addressing. ARM kernels are always linked at 0xCnnnnnnn. Depending
* on the headers, the offset value passed in may be physical or virtual
* (because it typically comes from e_entry), but we always replace
* whatever is passed in with the va<->pa offset. On the other hand, we
* always remove the high-order part of the entry address whether it's
* physical or virtual, because it will be adjusted later for the actual
* physical entry point based on where the image gets loaded.
*/
off = -0xc0000000;
ehdr->e_entry &= ~0xf0000000;
#ifdef ELF_VERBOSE
printf("ehdr->e_entry 0x%08x, va<->pa off %llx\n", ehdr->e_entry, off);
#endif
#else
off = 0; /* other archs use direct mapped kernels */
#endif
__elfN(relocation_offset) = off;
}
ef->off = off;
if ((ehdr->e_phoff + ehdr->e_phnum * sizeof(*phdr)) > ef->firstlen) {
printf("elf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: program header not within first page\n");
goto out;
}
phdr = (Elf_Phdr *)(ef->firstpage + ehdr->e_phoff);
for (i = 0; i < ehdr->e_phnum; i++) {
/* We want to load PT_LOAD segments only.. */
if (phdr[i].p_type != PT_LOAD)
continue;
#ifdef ELF_VERBOSE
printf("Segment: 0x%lx@0x%lx -> 0x%lx-0x%lx",
(long)phdr[i].p_filesz, (long)phdr[i].p_offset,
(long)(phdr[i].p_vaddr + off),
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
#else
if ((phdr[i].p_flags & PF_W) == 0) {
printf("text=0x%lx ", (long)phdr[i].p_filesz);
} else {
printf("data=0x%lx", (long)phdr[i].p_filesz);
if (phdr[i].p_filesz < phdr[i].p_memsz)
printf("+0x%lx", (long)(phdr[i].p_memsz -phdr[i].p_filesz));
printf(" ");
}
#endif
fpcopy = 0;
if (ef->firstlen > phdr[i].p_offset) {
fpcopy = ef->firstlen - phdr[i].p_offset;
archsw.arch_copyin(ef->firstpage + phdr[i].p_offset,
phdr[i].p_vaddr + off, fpcopy);
}
if (phdr[i].p_filesz > fpcopy) {
if (kern_pread(ef->fd, phdr[i].p_vaddr + off + fpcopy,
phdr[i].p_filesz - fpcopy, phdr[i].p_offset + fpcopy) != 0) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_loadimage: read failed\n");
goto out;
}
}
/* clear space from oversized segments; eg: bss */
if (phdr[i].p_filesz < phdr[i].p_memsz) {
#ifdef ELF_VERBOSE
printf(" (bss: 0x%lx-0x%lx)",
(long)(phdr[i].p_vaddr + off + phdr[i].p_filesz),
(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
#endif
kern_bzero(phdr[i].p_vaddr + off + phdr[i].p_filesz,
phdr[i].p_memsz - phdr[i].p_filesz);
}
#ifdef ELF_VERBOSE
printf("\n");
#endif
if (archsw.arch_loadseg != NULL)
archsw.arch_loadseg(ehdr, phdr + i, off);
if (firstaddr == 0 || firstaddr > (phdr[i].p_vaddr + off))
firstaddr = phdr[i].p_vaddr + off;
if (lastaddr == 0 || lastaddr < (phdr[i].p_vaddr + off + phdr[i].p_memsz))
lastaddr = phdr[i].p_vaddr + off + phdr[i].p_memsz;
}
lastaddr = roundup(lastaddr, sizeof(long));
/*
* Now grab the symbol tables. This isn't easy if we're reading a
* .gz file. I think the rule is going to have to be that you must
* strip a file to remove symbols before gzipping it so that we do not
* try to lseek() on it.
*/
chunk = ehdr->e_shnum * ehdr->e_shentsize;
if (chunk == 0 || ehdr->e_shoff == 0)
goto nosyms;
shdr = alloc_pread(ef->fd, ehdr->e_shoff, chunk);
if (shdr == NULL) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
"_loadimage: failed to read section headers");
goto nosyms;
}
file_addmetadata(fp, MODINFOMD_SHDR, chunk, shdr);
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < ehdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_SYMTAB)
continue;
for (j = 0; j < ehdr->e_phnum; j++) {
if (phdr[j].p_type != PT_LOAD)
continue;
if (shdr[i].sh_offset >= phdr[j].p_offset &&
(shdr[i].sh_offset + shdr[i].sh_size <=
phdr[j].p_offset + phdr[j].p_filesz)) {
shdr[i].sh_offset = 0;
shdr[i].sh_size = 0;
break;
}
}
if (shdr[i].sh_offset == 0 || shdr[i].sh_size == 0)
continue; /* alread loaded in a PT_LOAD above */
/* Save it for loading below */
symtabindex = i;
symstrindex = shdr[i].sh_link;
}
if (symtabindex < 0 || symstrindex < 0)
goto nosyms;
/* Ok, committed to a load. */
#ifndef ELF_VERBOSE
printf("syms=[");
#endif
ssym = lastaddr;
for (i = symtabindex; i >= 0; i = symstrindex) {
#ifdef ELF_VERBOSE
char *secname;
switch(shdr[i].sh_type) {
case SHT_SYMTAB: /* Symbol table */
secname = "symtab";
break;
case SHT_STRTAB: /* String table */
secname = "strtab";
break;
default:
secname = "WHOA!!";
break;
}
#endif
size = shdr[i].sh_size;
archsw.arch_copyin(&size, lastaddr, sizeof(size));
lastaddr += sizeof(size);
#ifdef ELF_VERBOSE
printf("\n%s: 0x%jx@0x%jx -> 0x%jx-0x%jx", secname,
(uintmax_t)shdr[i].sh_size, (uintmax_t)shdr[i].sh_offset,
(uintmax_t)lastaddr, (uintmax_t)(lastaddr + shdr[i].sh_size));
#else
if (i == symstrindex)
printf("+");
printf("0x%lx+0x%lx", (long)sizeof(size), (long)size);
#endif
if (lseek(ef->fd, (off_t)shdr[i].sh_offset, SEEK_SET) == -1) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: could not seek for symbols - skipped!");
lastaddr = ssym;
ssym = 0;
goto nosyms;
}
result = archsw.arch_readin(ef->fd, lastaddr, shdr[i].sh_size);
if (result < 0 || (size_t)result != shdr[i].sh_size) {
printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: could not read symbols - skipped! (%ju != %ju)", (uintmax_t)result,
(uintmax_t)shdr[i].sh_size);
lastaddr = ssym;
ssym = 0;
goto nosyms;
}
/* Reset offsets relative to ssym */
lastaddr += shdr[i].sh_size;
lastaddr = roundup(lastaddr, sizeof(size));
if (i == symtabindex)
symtabindex = -1;
else if (i == symstrindex)
symstrindex = -1;
}
esym = lastaddr;
#ifndef ELF_VERBOSE
printf("]");
#endif
file_addmetadata(fp, MODINFOMD_SSYM, sizeof(ssym), &ssym);
file_addmetadata(fp, MODINFOMD_ESYM, sizeof(esym), &esym);
nosyms:
printf("\n");
ret = lastaddr - firstaddr;
fp->f_addr = firstaddr;
php = NULL;
for (i = 0; i < ehdr->e_phnum; i++) {
if (phdr[i].p_type == PT_DYNAMIC) {
php = phdr + i;
adp = php->p_vaddr;
file_addmetadata(fp, MODINFOMD_DYNAMIC, sizeof(adp), &adp);
break;
}
}
if (php == NULL) /* this is bad, we cannot get to symbols or _DYNAMIC */
goto out;
ndp = php->p_filesz / sizeof(Elf_Dyn);
if (ndp == 0)
goto out;
dp = malloc(php->p_filesz);
if (dp == NULL)
goto out;
archsw.arch_copyout(php->p_vaddr + off, dp, php->p_filesz);
ef->strsz = 0;
for (i = 0; i < ndp; i++) {
if (dp[i].d_tag == 0)
break;
switch (dp[i].d_tag) {
case DT_HASH:
ef->hashtab = (Elf_Hashelt*)(uintptr_t)(dp[i].d_un.d_ptr + off);
break;
case DT_STRTAB:
ef->strtab = (char *)(uintptr_t)(dp[i].d_un.d_ptr + off);
break;
case DT_STRSZ:
ef->strsz = dp[i].d_un.d_val;
break;
case DT_SYMTAB:
ef->symtab = (Elf_Sym*)(uintptr_t)(dp[i].d_un.d_ptr + off);
break;
case DT_REL:
ef->rel = (Elf_Rel *)(uintptr_t)(dp[i].d_un.d_ptr + off);
break;
case DT_RELSZ:
ef->relsz = dp[i].d_un.d_val;
break;
case DT_RELA:
ef->rela = (Elf_Rela *)(uintptr_t)(dp[i].d_un.d_ptr + off);
break;
case DT_RELASZ:
ef->relasz = dp[i].d_un.d_val;
break;
default:
break;
}
}
if (ef->hashtab == NULL || ef->symtab == NULL ||
ef->strtab == NULL || ef->strsz == 0)
goto out;
COPYOUT(ef->hashtab, &ef->nbuckets, sizeof(ef->nbuckets));
COPYOUT(ef->hashtab + 1, &ef->nchains, sizeof(ef->nchains));
ef->buckets = ef->hashtab + 2;
ef->chains = ef->buckets + ef->nbuckets;
if (__elfN(parse_modmetadata)(fp, ef) == 0)
goto out;
if (ef->kernel) /* kernel must not depend on anything */
goto out;
out:
if (dp)
free(dp);
if (shdr)
free(shdr);
return ret;
}
static char invalid_name[] = "bad";
char *
fake_modname(const char *name)
{
const char *sp, *ep;
char *fp;
size_t len;
sp = strrchr(name, '/');
if (sp)
sp++;
else
sp = name;
ep = strrchr(name, '.');
if (ep) {
if (ep == name) {
sp = invalid_name;
ep = invalid_name + sizeof(invalid_name) - 1;
}
} else
ep = name + strlen(name);
len = ep - sp;
fp = malloc(len + 1);
if (fp == NULL)
return NULL;
memcpy(fp, sp, len);
fp[len] = '\0';
return fp;
}
#if (defined(__i386__) || defined(__powerpc__)) && __ELF_WORD_SIZE == 64
struct mod_metadata64 {
int md_version; /* structure version MDTV_* */
int md_type; /* type of entry MDT_* */
u_int64_t md_data; /* specific data */
u_int64_t md_cval; /* common string label */
};
#endif
int
__elfN(parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
{
struct mod_metadata md;
#if (defined(__i386__) || defined(__powerpc__)) && __ELF_WORD_SIZE == 64
struct mod_metadata64 md64;
#endif
struct mod_depend *mdepend;
struct mod_version mver;
Elf_Sym sym;
char *s;
int error, modcnt, minfolen;
Elf_Addr v, p, p_stop;
if (__elfN(lookup_symbol)(fp, ef, "__start_set_modmetadata_set", &sym) != 0)
return 0;
p = sym.st_value + ef->off;
if (__elfN(lookup_symbol)(fp, ef, "__stop_set_modmetadata_set", &sym) != 0)
return ENOENT;
p_stop = sym.st_value + ef->off;
modcnt = 0;
while (p < p_stop) {
COPYOUT(p, &v, sizeof(v));
error = __elfN(reloc_ptr)(fp, ef, p, &v, sizeof(v));
if (error == EOPNOTSUPP)
v += ef->off;
else if (error != 0)
return (error);
#if (defined(__i386__) || defined(__powerpc__)) && __ELF_WORD_SIZE == 64
COPYOUT(v, &md64, sizeof(md64));
error = __elfN(reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
if (error == EOPNOTSUPP) {
md64.md_cval += ef->off;
md64.md_data += ef->off;
} else if (error != 0)
return (error);
md.md_version = md64.md_version;
md.md_type = md64.md_type;
md.md_cval = (const char *)(uintptr_t)md64.md_cval;
md.md_data = (void *)(uintptr_t)md64.md_data;
#else
COPYOUT(v, &md, sizeof(md));
error = __elfN(reloc_ptr)(fp, ef, v, &md, sizeof(md));
if (error == EOPNOTSUPP) {
md.md_cval += ef->off;
md.md_data += ef->off;
} else if (error != 0)
return (error);
#endif
p += sizeof(Elf_Addr);
switch(md.md_type) {
case MDT_DEPEND:
if (ef->kernel) /* kernel must not depend on anything */
break;
s = strdupout((vm_offset_t)md.md_cval);
minfolen = sizeof(*mdepend) + strlen(s) + 1;
mdepend = malloc(minfolen);
if (mdepend == NULL)
return ENOMEM;
COPYOUT((vm_offset_t)md.md_data, mdepend, sizeof(*mdepend));
strcpy((char*)(mdepend + 1), s);
free(s);
file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, mdepend);
free(mdepend);
break;
case MDT_VERSION:
s = strdupout((vm_offset_t)md.md_cval);
COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
file_addmodule(fp, s, mver.mv_version, NULL);
free(s);
modcnt++;
break;
}
}
if (modcnt == 0) {
s = fake_modname(fp->f_name);
file_addmodule(fp, s, 1, NULL);
free(s);
}
return 0;
}
static unsigned long
elf_hash(const char *name)
{
const unsigned char *p = (const unsigned char *) name;
unsigned long h = 0;
unsigned long g;
while (*p != '\0') {
h = (h << 4) + *p++;
if ((g = h & 0xf0000000) != 0)
h ^= g >> 24;
h &= ~g;
}
return h;
}
static const char __elfN(bad_symtable)[] = "elf" __XSTRING(__ELF_WORD_SIZE) "_lookup_symbol: corrupt symbol table\n";
int
__elfN(lookup_symbol)(struct preloaded_file *fp, elf_file_t ef, const char* name,
Elf_Sym *symp)
{
Elf_Hashelt symnum;
Elf_Sym sym;
char *strp;
unsigned long hash;
hash = elf_hash(name);
COPYOUT(&ef->buckets[hash % ef->nbuckets], &symnum, sizeof(symnum));
while (symnum != STN_UNDEF) {
if (symnum >= ef->nchains) {
printf(__elfN(bad_symtable));
return ENOENT;
}
COPYOUT(ef->symtab + symnum, &sym, sizeof(sym));
if (sym.st_name == 0) {
printf(__elfN(bad_symtable));
return ENOENT;
}
strp = strdupout((vm_offset_t)(ef->strtab + sym.st_name));
if (strcmp(name, strp) == 0) {
free(strp);
if (sym.st_shndx != SHN_UNDEF ||
(sym.st_value != 0 &&
ELF_ST_TYPE(sym.st_info) == STT_FUNC)) {
*symp = sym;
return 0;
}
return ENOENT;
}
free(strp);
COPYOUT(&ef->chains[symnum], &symnum, sizeof(symnum));
}
return ENOENT;
}
/*
* Apply any intra-module relocations to the value. p is the load address
* of the value and val/len is the value to be modified. This does NOT modify
* the image in-place, because this is done by kern_linker later on.
*
* Returns EOPNOTSUPP if no relocation method is supplied.
*/
static int
__elfN(reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
Elf_Addr p, void *val, size_t len)
{
size_t n;
Elf_Rela a;
Elf_Rel r;
int error;
/*
* The kernel is already relocated, but we still want to apply
* offset adjustments.
*/
if (ef->kernel)
return (EOPNOTSUPP);
for (n = 0; n < ef->relsz / sizeof(r); n++) {
COPYOUT(ef->rel + n, &r, sizeof(r));
error = __elfN(reloc)(ef, __elfN(symaddr), &r, ELF_RELOC_REL,
ef->off, p, val, len);
if (error != 0)
return (error);
}
for (n = 0; n < ef->relasz / sizeof(a); n++) {
COPYOUT(ef->rela + n, &a, sizeof(a));
error = __elfN(reloc)(ef, __elfN(symaddr), &a, ELF_RELOC_RELA,
ef->off, p, val, len);
if (error != 0)
return (error);
}
return (0);
}
static Elf_Addr
__elfN(symaddr)(struct elf_file *ef, Elf_Size symidx)
{
/* Symbol lookup by index not required here. */
return (0);
}
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