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freebsd-skq/sys/kern/link_elf_obj.c
glebius 75fbfbcc07 Reduce stack usage in link_elf_load_file(), allocating struct nameidata. 
This function may be called recursively, when a module pulls its dependencies.
Under certain circumstances, e.g. quad chain of dependencies and presence
of dtrace we may run out of stack.
2017-03-09 00:45:15 +00:00

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/*-
* Copyright (c) 1998-2000 Doug Rabson
* Copyright (c) 2004 Peter Wemm
* 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 "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include <machine/elf.h>
#include <net/vnet.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/link_elf.h>
#ifdef DDB_CTF
#include <sys/zlib.h>
#endif
#include "linker_if.h"
typedef struct {
void *addr;
Elf_Off size;
int flags;
int sec; /* Original section */
char *name;
} Elf_progent;
typedef struct {
Elf_Rel *rel;
int nrel;
int sec;
} Elf_relent;
typedef struct {
Elf_Rela *rela;
int nrela;
int sec;
} Elf_relaent;
typedef struct elf_file {
struct linker_file lf; /* Common fields */
int preloaded;
caddr_t address; /* Relocation address */
vm_object_t object; /* VM object to hold file pages */
Elf_Shdr *e_shdr;
Elf_progent *progtab;
int nprogtab;
Elf_relaent *relatab;
int nrelatab;
Elf_relent *reltab;
int nreltab;
Elf_Sym *ddbsymtab; /* The symbol table we are using */
long ddbsymcnt; /* Number of symbols */
caddr_t ddbstrtab; /* String table */
long ddbstrcnt; /* number of bytes in string table */
caddr_t shstrtab; /* Section name string table */
long shstrcnt; /* number of bytes in string table */
caddr_t ctftab; /* CTF table */
long ctfcnt; /* number of bytes in CTF table */
caddr_t ctfoff; /* CTF offset table */
caddr_t typoff; /* Type offset table */
long typlen; /* Number of type entries. */
} *elf_file_t;
#include <kern/kern_ctf.c>
static int link_elf_link_preload(linker_class_t cls,
const char *, linker_file_t *);
static int link_elf_link_preload_finish(linker_file_t);
static int link_elf_load_file(linker_class_t, const char *, linker_file_t *);
static int link_elf_lookup_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
linker_symval_t *);
static int link_elf_search_symbol(linker_file_t, caddr_t value,
c_linker_sym_t *sym, long *diffp);
static void link_elf_unload_file(linker_file_t);
static int link_elf_lookup_set(linker_file_t, const char *,
void ***, void ***, int *);
static int link_elf_each_function_name(linker_file_t,
int (*)(const char *, void *), void *);
static int link_elf_each_function_nameval(linker_file_t,
linker_function_nameval_callback_t,
void *);
static int link_elf_reloc_local(linker_file_t);
static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long link_elf_strtab_get(linker_file_t, caddr_t *);
static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
Elf_Addr *);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
KOBJMETHOD(linker_unload, link_elf_unload_file),
KOBJMETHOD(linker_load_file, link_elf_load_file),
KOBJMETHOD(linker_link_preload, link_elf_link_preload),
KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish),
KOBJMETHOD(linker_lookup_set, link_elf_lookup_set),
KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
{ 0, 0 }
};
static struct linker_class link_elf_class = {
#if ELF_TARG_CLASS == ELFCLASS32
"elf32_obj",
#else
"elf64_obj",
#endif
link_elf_methods, sizeof(struct elf_file)
};
static int relocate_file(elf_file_t ef);
static void elf_obj_cleanup_globals_cache(elf_file_t);
static void
link_elf_error(const char *filename, const char *s)
{
if (filename == NULL)
printf("kldload: %s\n", s);
else
printf("kldload: %s: %s\n", filename, s);
}
static void
link_elf_init(void *arg)
{
linker_add_class(&link_elf_class);
}
SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0);
static int
link_elf_link_preload(linker_class_t cls, const char *filename,
linker_file_t *result)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
void *modptr, *baseptr, *sizeptr;
char *type;
elf_file_t ef;
linker_file_t lf;
Elf_Addr off;
int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex;
/* Look to see if we have the file preloaded */
modptr = preload_search_by_name(filename);
if (modptr == NULL)
return ENOENT;
type = (char *)preload_search_info(modptr, MODINFO_TYPE);
baseptr = preload_search_info(modptr, MODINFO_ADDR);
sizeptr = preload_search_info(modptr, MODINFO_SIZE);
hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA |
MODINFOMD_ELFHDR);
shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA |
MODINFOMD_SHDR);
if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE)
" obj module") != 0 &&
strcmp(type, "elf obj module") != 0)) {
return (EFTYPE);
}
if (baseptr == NULL || sizeptr == NULL || hdr == NULL ||
shdr == NULL)
return (EINVAL);
lf = linker_make_file(filename, &link_elf_class);
if (lf == NULL)
return (ENOMEM);
ef = (elf_file_t)lf;
ef->preloaded = 1;
ef->address = *(caddr_t *)baseptr;
lf->address = *(caddr_t *)baseptr;
lf->size = *(size_t *)sizeptr;
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT ||
hdr->e_type != ET_REL ||
hdr->e_machine != ELF_TARG_MACH) {
error = EFTYPE;
goto out;
}
ef->e_shdr = shdr;
/* Scan the section header for information and table sizing. */
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
ef->nprogtab++;
break;
case SHT_SYMTAB:
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ef->nreltab++;
break;
case SHT_RELA:
ef->nrelatab++;
break;
}
}
shstrindex = hdr->e_shstrndx;
if (ef->nprogtab == 0 || symstrindex < 0 ||
symstrindex >= hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 ||
shstrindex >= hdr->e_shnum ||
shdr[shstrindex].sh_type != SHT_STRTAB) {
printf("%s: bad/missing section headers\n", filename);
error = ENOEXEC;
goto out;
}
/* Allocate space for tracking the load chunks */
if (ef->nprogtab != 0)
ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nreltab != 0)
ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nrelatab != 0)
ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
M_LINKER, M_WAITOK | M_ZERO);
if ((ef->nprogtab != 0 && ef->progtab == NULL) ||
(ef->nreltab != 0 && ef->reltab == NULL) ||
(ef->nrelatab != 0 && ef->relatab == NULL)) {
error = ENOMEM;
goto out;
}
/* XXX, relocate the sh_addr fields saved by the loader. */
off = 0;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off))
off = shdr[i].sh_addr;
}
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_addr != 0)
shdr[i].sh_addr = shdr[i].sh_addr - off +
(Elf_Addr)ef->address;
}
ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr;
ef->ddbstrcnt = shdr[symstrindex].sh_size;
ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr;
ef->shstrcnt = shdr[shstrindex].sh_size;
ef->shstrtab = (char *)shdr[shstrindex].sh_addr;
/* Now fill out progtab and the relocation tables. */
pb = 0;
rl = 0;
ra = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
ef->progtab[pb].addr = (void *)shdr[i].sh_addr;
if (shdr[i].sh_type == SHT_PROGBITS)
ef->progtab[pb].name = "<<PROGBITS>>";
#ifdef __amd64__
else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
ef->progtab[pb].name = "<<UNWIND>>";
#endif
else
ef->progtab[pb].name = "<<NOBITS>>";
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].sec = i;
if (ef->shstrtab && shdr[i].sh_name != 0)
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) {
void *dpcpu;
dpcpu = dpcpu_alloc(shdr[i].sh_size);
if (dpcpu == NULL) {
error = ENOSPC;
goto out;
}
memcpy(dpcpu, ef->progtab[pb].addr,
ef->progtab[pb].size);
dpcpu_copy(dpcpu, shdr[i].sh_size);
ef->progtab[pb].addr = dpcpu;
#ifdef VIMAGE
} else if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, VNET_SETNAME)) {
void *vnet_data;
vnet_data = vnet_data_alloc(shdr[i].sh_size);
if (vnet_data == NULL) {
error = ENOSPC;
goto out;
}
memcpy(vnet_data, ef->progtab[pb].addr,
ef->progtab[pb].size);
vnet_data_copy(vnet_data, shdr[i].sh_size);
ef->progtab[pb].addr = vnet_data;
#endif
} else if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, ".ctors")) {
lf->ctors_addr = ef->progtab[pb].addr;
lf->ctors_size = shdr[i].sh_size;
}
/* Update all symbol values with the offset. */
for (j = 0; j < ef->ddbsymcnt; j++) {
es = &ef->ddbsymtab[j];
if (es->st_shndx != i)
continue;
es->st_value += (Elf_Addr)ef->progtab[pb].addr;
}
pb++;
break;
case SHT_REL:
ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr;
ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
ef->reltab[rl].sec = shdr[i].sh_info;
rl++;
break;
case SHT_RELA:
ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr;
ef->relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ef->relatab[ra].sec = shdr[i].sh_info;
ra++;
break;
}
}
if (pb != ef->nprogtab) {
printf("%s: lost progbits\n", filename);
error = ENOEXEC;
goto out;
}
if (rl != ef->nreltab) {
printf("%s: lost reltab\n", filename);
error = ENOEXEC;
goto out;
}
if (ra != ef->nrelatab) {
printf("%s: lost relatab\n", filename);
error = ENOEXEC;
goto out;
}
/* Local intra-module relocations */
error = link_elf_reloc_local(lf);
if (error != 0)
goto out;
*result = lf;
return (0);
out:
/* preload not done this way */
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
return (error);
}
static void
link_elf_invoke_ctors(caddr_t addr, size_t size)
{
void (**ctor)(void);
size_t i, cnt;
if (addr == NULL || size == 0)
return;
cnt = size / sizeof(*ctor);
ctor = (void *)addr;
for (i = 0; i < cnt; i++) {
if (ctor[i] != NULL)
(*ctor[i])();
}
}
static int
link_elf_link_preload_finish(linker_file_t lf)
{
elf_file_t ef;
int error;
ef = (elf_file_t)lf;
error = relocate_file(ef);
if (error)
return error;
/* Notify MD code that a module is being loaded. */
error = elf_cpu_load_file(lf);
if (error)
return (error);
/* Invoke .ctors */
link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
return (0);
}
static int
link_elf_load_file(linker_class_t cls, const char *filename,
linker_file_t *result)
{
struct nameidata *nd;
struct thread *td = curthread; /* XXX */
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
int nbytes, i, j;
vm_offset_t mapbase;
size_t mapsize;
int error = 0;
ssize_t resid;
int flags;
elf_file_t ef;
linker_file_t lf;
int symtabindex;
int symstrindex;
int shstrindex;
int nsym;
int pb, rl, ra;
int alignmask;
shdr = NULL;
lf = NULL;
mapsize = 0;
hdr = NULL;
nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK);
NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td);
flags = FREAD;
error = vn_open(nd, &flags, 0, NULL);
if (error) {
free(nd, M_TEMP);
return error;
}
NDFREE(nd, NDF_ONLY_PNBUF);
if (nd->ni_vp->v_type != VREG) {
error = ENOEXEC;
goto out;
}
#ifdef MAC
error = mac_kld_check_load(td->td_ucred, nd->ni_vp);
if (error) {
goto out;
}
#endif
/* Read the elf header from the file. */
hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK);
error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = ENOEXEC;
goto out;
}
if (!IS_ELF(*hdr)) {
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS
|| hdr->e_ident[EI_DATA] != ELF_TARG_DATA) {
link_elf_error(filename, "Unsupported file layout");
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_VERSION] != EV_CURRENT
|| hdr->e_version != EV_CURRENT) {
link_elf_error(filename, "Unsupported file version");
error = ENOEXEC;
goto out;
}
if (hdr->e_type != ET_REL) {
error = ENOSYS;
goto out;
}
if (hdr->e_machine != ELF_TARG_MACH) {
link_elf_error(filename, "Unsupported machine");
error = ENOEXEC;
goto out;
}
lf = linker_make_file(filename, &link_elf_class);
if (!lf) {
error = ENOMEM;
goto out;
}
ef = (elf_file_t) lf;
ef->nprogtab = 0;
ef->e_shdr = 0;
ef->nreltab = 0;
ef->nrelatab = 0;
/* Allocate and read in the section header */
nbytes = hdr->e_shnum * hdr->e_shentsize;
if (nbytes == 0 || hdr->e_shoff == 0 ||
hdr->e_shentsize != sizeof(Elf_Shdr)) {
error = ENOEXEC;
goto out;
}
shdr = malloc(nbytes, M_LINKER, M_WAITOK);
ef->e_shdr = shdr;
error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes,
hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
NOCRED, &resid, td);
if (error)
goto out;
if (resid) {
error = ENOEXEC;
goto out;
}
/* Scan the section header for information and table sizing. */
nsym = 0;
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_size == 0)
continue;
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
ef->nprogtab++;
break;
case SHT_SYMTAB:
nsym++;
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ef->nreltab++;
break;
case SHT_RELA:
ef->nrelatab++;
break;
case SHT_STRTAB:
break;
}
}
if (ef->nprogtab == 0) {
link_elf_error(filename, "file has no contents");
error = ENOEXEC;
goto out;
}
if (nsym != 1) {
/* Only allow one symbol table for now */
link_elf_error(filename, "file has no valid symbol table");
error = ENOEXEC;
goto out;
}
if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB) {
link_elf_error(filename, "file has invalid symbol strings");
error = ENOEXEC;
goto out;
}
/* Allocate space for tracking the load chunks */
if (ef->nprogtab != 0)
ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nreltab != 0)
ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab),
M_LINKER, M_WAITOK | M_ZERO);
if (ef->nrelatab != 0)
ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab),
M_LINKER, M_WAITOK | M_ZERO);
if (symtabindex == -1) {
link_elf_error(filename, "lost symbol table index");
error = ENOEXEC;
goto out;
}
/* Allocate space for and load the symbol table */
ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK);
error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab,
shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
if (symstrindex == -1) {
link_elf_error(filename, "lost symbol string index");
error = ENOEXEC;
goto out;
}
/* Allocate space for and load the symbol strings */
ef->ddbstrcnt = shdr[symstrindex].sh_size;
ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK);
error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab,
shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
/* Do we have a string table for the section names? */
shstrindex = -1;
if (hdr->e_shstrndx != 0 &&
shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
shstrindex = hdr->e_shstrndx;
ef->shstrcnt = shdr[shstrindex].sh_size;
ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER,
M_WAITOK);
error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab,
shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
}
/* Size up code/data(progbits) and bss(nobits). */
alignmask = 0;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_size == 0)
continue;
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
alignmask = shdr[i].sh_addralign - 1;
mapsize += alignmask;
mapsize &= ~alignmask;
mapsize += shdr[i].sh_size;
break;
}
}
/*
* We know how much space we need for the text/data/bss/etc.
* This stuff needs to be in a single chunk so that profiling etc
* can get the bounds and gdb can associate offsets with modules
*/
ef->object = vm_object_allocate(OBJT_DEFAULT,
round_page(mapsize) >> PAGE_SHIFT);
if (ef->object == NULL) {
error = ENOMEM;
goto out;
}
ef->address = (caddr_t) vm_map_min(kernel_map);
/*
* In order to satisfy amd64's architectural requirements on the
* location of code and data in the kernel's address space, request a
* mapping that is above the kernel.
*/
#ifdef __amd64__
mapbase = KERNBASE;
#else
mapbase = VM_MIN_KERNEL_ADDRESS;
#endif
error = vm_map_find(kernel_map, ef->object, 0, &mapbase,
round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL,
VM_PROT_ALL, 0);
if (error) {
vm_object_deallocate(ef->object);
ef->object = 0;
goto out;
}
/* Wire the pages */
error = vm_map_wire(kernel_map, mapbase,
mapbase + round_page(mapsize),
VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
if (error != KERN_SUCCESS) {
error = ENOMEM;
goto out;
}
/* Inform the kld system about the situation */
lf->address = ef->address = (caddr_t)mapbase;
lf->size = mapsize;
/*
* Now load code/data(progbits), zero bss(nobits), allocate space for
* and load relocs
*/
pb = 0;
rl = 0;
ra = 0;
alignmask = 0;
for (i = 0; i < hdr->e_shnum; i++) {
if (shdr[i].sh_size == 0)
continue;
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
#ifdef __amd64__
case SHT_X86_64_UNWIND:
#endif
alignmask = shdr[i].sh_addralign - 1;
mapbase += alignmask;
mapbase &= ~alignmask;
if (ef->shstrtab != NULL && shdr[i].sh_name != 0) {
ef->progtab[pb].name =
ef->shstrtab + shdr[i].sh_name;
if (!strcmp(ef->progtab[pb].name, ".ctors")) {
lf->ctors_addr = (caddr_t)mapbase;
lf->ctors_size = shdr[i].sh_size;
}
} else if (shdr[i].sh_type == SHT_PROGBITS)
ef->progtab[pb].name = "<<PROGBITS>>";
#ifdef __amd64__
else if (shdr[i].sh_type == SHT_X86_64_UNWIND)
ef->progtab[pb].name = "<<UNWIND>>";
#endif
else
ef->progtab[pb].name = "<<NOBITS>>";
if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
ef->progtab[pb].addr =
dpcpu_alloc(shdr[i].sh_size);
#ifdef VIMAGE
else if (ef->progtab[pb].name != NULL &&
!strcmp(ef->progtab[pb].name, VNET_SETNAME))
ef->progtab[pb].addr =
vnet_data_alloc(shdr[i].sh_size);
#endif
else
ef->progtab[pb].addr =
(void *)(uintptr_t)mapbase;
if (ef->progtab[pb].addr == NULL) {
error = ENOSPC;
goto out;
}
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].sec = i;
if (shdr[i].sh_type == SHT_PROGBITS
#ifdef __amd64__
|| shdr[i].sh_type == SHT_X86_64_UNWIND
#endif
) {
error = vn_rdwr(UIO_READ, nd->ni_vp,
ef->progtab[pb].addr,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
NOCRED, &resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
/* Initialize the per-cpu or vnet area. */
if (ef->progtab[pb].addr != (void *)mapbase &&
!strcmp(ef->progtab[pb].name, DPCPU_SETNAME))
dpcpu_copy(ef->progtab[pb].addr,
shdr[i].sh_size);
#ifdef VIMAGE
else if (ef->progtab[pb].addr !=
(void *)mapbase &&
!strcmp(ef->progtab[pb].name, VNET_SETNAME))
vnet_data_copy(ef->progtab[pb].addr,
shdr[i].sh_size);
#endif
} else
bzero(ef->progtab[pb].addr, shdr[i].sh_size);
/* Update all symbol values with the offset. */
for (j = 0; j < ef->ddbsymcnt; j++) {
es = &ef->ddbsymtab[j];
if (es->st_shndx != i)
continue;
es->st_value += (Elf_Addr)ef->progtab[pb].addr;
}
mapbase += shdr[i].sh_size;
pb++;
break;
case SHT_REL:
ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER,
M_WAITOK);
ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel);
ef->reltab[rl].sec = shdr[i].sh_info;
error = vn_rdwr(UIO_READ, nd->ni_vp,
(void *)ef->reltab[rl].rel,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
rl++;
break;
case SHT_RELA:
ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER,
M_WAITOK);
ef->relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ef->relatab[ra].sec = shdr[i].sh_info;
error = vn_rdwr(UIO_READ, nd->ni_vp,
(void *)ef->relatab[ra].rela,
shdr[i].sh_size, shdr[i].sh_offset,
UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED,
&resid, td);
if (error)
goto out;
if (resid != 0){
error = EINVAL;
goto out;
}
ra++;
break;
}
}
if (pb != ef->nprogtab) {
link_elf_error(filename, "lost progbits");
error = ENOEXEC;
goto out;
}
if (rl != ef->nreltab) {
link_elf_error(filename, "lost reltab");
error = ENOEXEC;
goto out;
}
if (ra != ef->nrelatab) {
link_elf_error(filename, "lost relatab");
error = ENOEXEC;
goto out;
}
if (mapbase != (vm_offset_t)ef->address + mapsize) {
printf(
"%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n",
filename != NULL ? filename : "<none>",
(u_long)mapbase, ef->address, (u_long)mapsize,
(u_long)(vm_offset_t)ef->address + mapsize);
error = ENOMEM;
goto out;
}
/* Local intra-module relocations */
error = link_elf_reloc_local(lf);
if (error != 0)
goto out;
/* Pull in dependencies */
VOP_UNLOCK(nd->ni_vp, 0);
error = linker_load_dependencies(lf);
vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY);
if (error)
goto out;
/* External relocations */
error = relocate_file(ef);
if (error)
goto out;
/* Notify MD code that a module is being loaded. */
error = elf_cpu_load_file(lf);
if (error)
goto out;
/* Invoke .ctors */
link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size);
*result = lf;
out:
VOP_UNLOCK(nd->ni_vp, 0);
vn_close(nd->ni_vp, FREAD, td->td_ucred, td);
free(nd, M_TEMP);
if (error && lf)
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
free(hdr, M_LINKER);
return error;
}
static void
link_elf_unload_file(linker_file_t file)
{
elf_file_t ef = (elf_file_t) file;
int i;
/* Notify MD code that a module is being unloaded. */
elf_cpu_unload_file(file);
if (ef->progtab) {
for (i = 0; i < ef->nprogtab; i++) {
if (ef->progtab[i].size == 0)
continue;
if (ef->progtab[i].name == NULL)
continue;
if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME))
dpcpu_free(ef->progtab[i].addr,
ef->progtab[i].size);
#ifdef VIMAGE
else if (!strcmp(ef->progtab[i].name, VNET_SETNAME))
vnet_data_free(ef->progtab[i].addr,
ef->progtab[i].size);
#endif
}
}
if (ef->preloaded) {
free(ef->reltab, M_LINKER);
free(ef->relatab, M_LINKER);
free(ef->progtab, M_LINKER);
free(ef->ctftab, M_LINKER);
free(ef->ctfoff, M_LINKER);
free(ef->typoff, M_LINKER);
if (file->filename != NULL)
preload_delete_name(file->filename);
/* XXX reclaim module memory? */
return;
}
for (i = 0; i < ef->nreltab; i++)
free(ef->reltab[i].rel, M_LINKER);
for (i = 0; i < ef->nrelatab; i++)
free(ef->relatab[i].rela, M_LINKER);
free(ef->reltab, M_LINKER);
free(ef->relatab, M_LINKER);
free(ef->progtab, M_LINKER);
if (ef->object) {
vm_map_remove(kernel_map, (vm_offset_t) ef->address,
(vm_offset_t) ef->address +
(ef->object->size << PAGE_SHIFT));
}
free(ef->e_shdr, M_LINKER);
free(ef->ddbsymtab, M_LINKER);
free(ef->ddbstrtab, M_LINKER);
free(ef->shstrtab, M_LINKER);
free(ef->ctftab, M_LINKER);
free(ef->ctfoff, M_LINKER);
free(ef->typoff, M_LINKER);
}
static const char *
symbol_name(elf_file_t ef, Elf_Size r_info)
{
const Elf_Sym *ref;
if (ELF_R_SYM(r_info)) {
ref = ef->ddbsymtab + ELF_R_SYM(r_info);
return ef->ddbstrtab + ref->st_name;
} else
return NULL;
}
static Elf_Addr
findbase(elf_file_t ef, int sec)
{
int i;
Elf_Addr base = 0;
for (i = 0; i < ef->nprogtab; i++) {
if (sec == ef->progtab[i].sec) {
base = (Elf_Addr)ef->progtab[i].addr;
break;
}
}
return base;
}
static int
relocate_file(elf_file_t ef)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const char *symname;
const Elf_Sym *sym;
int i;
Elf_Size symidx;
Elf_Addr base;
/* Perform relocations without addend if there are any: */
for (i = 0; i < ef->nreltab; i++) {
rel = ef->reltab[i].rel;
if (rel == NULL) {
link_elf_error(ef->lf.filename, "lost a reltab!");
return (ENOEXEC);
}
rellim = rel + ef->reltab[i].nrel;
base = findbase(ef, ef->reltab[i].sec);
if (base == 0) {
link_elf_error(ef->lf.filename, "lost base for reltab");
return (ENOEXEC);
}
for ( ; rel < rellim; rel++) {
symidx = ELF_R_SYM(rel->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Local relocs are already done */
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
continue;
if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL,
elf_obj_lookup)) {
symname = symbol_name(ef, rel->r_info);
printf("link_elf_obj: symbol %s undefined\n",
symname);
return (ENOENT);
}
}
}
/* Perform relocations with addend if there are any: */
for (i = 0; i < ef->nrelatab; i++) {
rela = ef->relatab[i].rela;
if (rela == NULL) {
link_elf_error(ef->lf.filename, "lost a relatab!");
return (ENOEXEC);
}
relalim = rela + ef->relatab[i].nrela;
base = findbase(ef, ef->relatab[i].sec);
if (base == 0) {
link_elf_error(ef->lf.filename,
"lost base for relatab");
return (ENOEXEC);
}
for ( ; rela < relalim; rela++) {
symidx = ELF_R_SYM(rela->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Local relocs are already done */
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL)
continue;
if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA,
elf_obj_lookup)) {
symname = symbol_name(ef, rela->r_info);
printf("link_elf_obj: symbol %s undefined\n",
symname);
return (ENOENT);
}
}
}
/*
* Only clean SHN_FBSD_CACHED for successful return. If we
* modified symbol table for the object but found an
* unresolved symbol, there is no reason to roll back.
*/
elf_obj_cleanup_globals_cache(ef);
return (0);
}
static int
link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
elf_file_t ef = (elf_file_t) lf;
const Elf_Sym *symp;
const char *strp;
int i;
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
strp = ef->ddbstrtab + symp->st_name;
if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) {
*sym = (c_linker_sym_t) symp;
return 0;
}
}
return ENOENT;
}
static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
elf_file_t ef = (elf_file_t) lf;
const Elf_Sym *es = (const Elf_Sym*) sym;
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
symval->name = ef->ddbstrtab + es->st_name;
symval->value = (caddr_t)es->st_value;
symval->size = es->st_size;
return 0;
}
return ENOENT;
}
static int
link_elf_search_symbol(linker_file_t lf, caddr_t value,
c_linker_sym_t *sym, long *diffp)
{
elf_file_t ef = (elf_file_t) lf;
u_long off = (uintptr_t) (void *) value;
u_long diff = off;
u_long st_value;
const Elf_Sym *es;
const Elf_Sym *best = NULL;
int i;
for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) {
if (es->st_name == 0)
continue;
st_value = es->st_value;
if (off >= st_value) {
if (off - st_value < diff) {
diff = off - st_value;
best = es;
if (diff == 0)
break;
} else if (off - st_value == diff) {
best = es;
}
}
}
if (best == NULL)
*diffp = off;
else
*diffp = diff;
*sym = (c_linker_sym_t) best;
return 0;
}
/*
* Look up a linker set on an ELF system.
*/
static int
link_elf_lookup_set(linker_file_t lf, const char *name,
void ***startp, void ***stopp, int *countp)
{
elf_file_t ef = (elf_file_t)lf;
void **start, **stop;
int i, count;
/* Relative to section number */
for (i = 0; i < ef->nprogtab; i++) {
if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) &&
strcmp(ef->progtab[i].name + 4, name) == 0) {
start = (void **)ef->progtab[i].addr;
stop = (void **)((char *)ef->progtab[i].addr +
ef->progtab[i].size);
count = stop - start;
if (startp)
*startp = start;
if (stopp)
*stopp = stop;
if (countp)
*countp = count;
return (0);
}
}
return (ESRCH);
}
static int
link_elf_each_function_name(linker_file_t file,
int (*callback)(const char *, void *), void *opaque)
{
elf_file_t ef = (elf_file_t)file;
const Elf_Sym *symp;
int i, error;
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
error = callback(ef->ddbstrtab + symp->st_name, opaque);
if (error)
return (error);
}
}
return (0);
}
static int
link_elf_each_function_nameval(linker_file_t file,
linker_function_nameval_callback_t callback, void *opaque)
{
linker_symval_t symval;
elf_file_t ef = (elf_file_t)file;
const Elf_Sym* symp;
int i, error;
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval);
if (error)
return (error);
error = callback(file, i, &symval, opaque);
if (error)
return (error);
}
}
return (0);
}
static void
elf_obj_cleanup_globals_cache(elf_file_t ef)
{
Elf_Sym *sym;
Elf_Size i;
for (i = 0; i < ef->ddbsymcnt; i++) {
sym = ef->ddbsymtab + i;
if (sym->st_shndx == SHN_FBSD_CACHED) {
sym->st_shndx = SHN_UNDEF;
sym->st_value = 0;
}
}
}
/*
* Symbol lookup function that can be used when the symbol index is known (ie
* in relocations). It uses the symbol index instead of doing a fully fledged
* hash table based lookup when such is valid. For example for local symbols.
* This is not only more efficient, it's also more correct. It's not always
* the case that the symbol can be found through the hash table.
*/
static int
elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
{
elf_file_t ef = (elf_file_t)lf;
Elf_Sym *sym;
const char *symbol;
Elf_Addr res1;
/* Don't even try to lookup the symbol if the index is bogus. */
if (symidx >= ef->ddbsymcnt) {
*res = 0;
return (EINVAL);
}
sym = ef->ddbsymtab + symidx;
/* Quick answer if there is a definition included. */
if (sym->st_shndx != SHN_UNDEF) {
*res = sym->st_value;
return (0);
}
/* If we get here, then it is undefined and needs a lookup. */
switch (ELF_ST_BIND(sym->st_info)) {
case STB_LOCAL:
/* Local, but undefined? huh? */
*res = 0;
return (EINVAL);
case STB_GLOBAL:
case STB_WEAK:
/* Relative to Data or Function name */
symbol = ef->ddbstrtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
if (*symbol == 0) {
*res = 0;
return (EINVAL);
}
res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
/*
* Cache global lookups during module relocation. The failure
* case is particularly expensive for callers, who must scan
* through the entire globals table doing strcmp(). Cache to
* avoid doing such work repeatedly.
*
* After relocation is complete, undefined globals will be
* restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
* above.
*/
if (res1 != 0) {
sym->st_shndx = SHN_FBSD_CACHED;
sym->st_value = res1;
*res = res1;
return (0);
} else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
sym->st_value = 0;
*res = 0;
return (0);
}
return (EINVAL);
default:
return (EINVAL);
}
}
static void
link_elf_fix_link_set(elf_file_t ef)
{
static const char startn[] = "__start_";
static const char stopn[] = "__stop_";
Elf_Sym *sym;
const char *sym_name, *linkset_name;
Elf_Addr startp, stopp;
Elf_Size symidx;
int start, i;
startp = stopp = 0;
for (symidx = 1 /* zero entry is special */;
symidx < ef->ddbsymcnt; symidx++) {
sym = ef->ddbsymtab + symidx;
if (sym->st_shndx != SHN_UNDEF)
continue;
sym_name = ef->ddbstrtab + sym->st_name;
if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) {
start = 1;
linkset_name = sym_name + sizeof(startn) - 1;
}
else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) {
start = 0;
linkset_name = sym_name + sizeof(stopn) - 1;
}
else
continue;
for (i = 0; i < ef->nprogtab; i++) {
if (strcmp(ef->progtab[i].name, linkset_name) == 0) {
startp = (Elf_Addr)ef->progtab[i].addr;
stopp = (Elf_Addr)(startp + ef->progtab[i].size);
break;
}
}
if (i == ef->nprogtab)
continue;
sym->st_value = start ? startp : stopp;
sym->st_shndx = i;
}
}
static int
link_elf_reloc_local(linker_file_t lf)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const Elf_Sym *sym;
Elf_Addr base;
int i;
Elf_Size symidx;
link_elf_fix_link_set(ef);
/* Perform relocations without addend if there are any: */
for (i = 0; i < ef->nreltab; i++) {
rel = ef->reltab[i].rel;
if (rel == NULL) {
link_elf_error(ef->lf.filename, "lost a reltab");
return (ENOEXEC);
}
rellim = rel + ef->reltab[i].nrel;
base = findbase(ef, ef->reltab[i].sec);
if (base == 0) {
link_elf_error(ef->lf.filename, "lost base for reltab");
return (ENOEXEC);
}
for ( ; rel < rellim; rel++) {
symidx = ELF_R_SYM(rel->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Only do local relocs */
if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
continue;
elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
elf_obj_lookup);
}
}
/* Perform relocations with addend if there are any: */
for (i = 0; i < ef->nrelatab; i++) {
rela = ef->relatab[i].rela;
if (rela == NULL) {
link_elf_error(ef->lf.filename, "lost a relatab!");
return (ENOEXEC);
}
relalim = rela + ef->relatab[i].nrela;
base = findbase(ef, ef->relatab[i].sec);
if (base == 0) {
link_elf_error(ef->lf.filename, "lost base for reltab");
return (ENOEXEC);
}
for ( ; rela < relalim; rela++) {
symidx = ELF_R_SYM(rela->r_info);
if (symidx >= ef->ddbsymcnt)
continue;
sym = ef->ddbsymtab + symidx;
/* Only do local relocs */
if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
continue;
elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
elf_obj_lookup);
}
}
return (0);
}
static long
link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab)
{
elf_file_t ef = (elf_file_t)lf;
*symtab = ef->ddbsymtab;
if (*symtab == NULL)
return (0);
return (ef->ddbsymcnt);
}
static long
link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
{
elf_file_t ef = (elf_file_t)lf;
*strtab = ef->ddbstrtab;
if (*strtab == NULL)
return (0);
return (ef->ddbstrcnt);
}
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