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NetBSD/sys/kern/subr_kobj.c

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/* $NetBSD: subr_kobj.c,v 1.22 2008/10/06 10:46:58 ad Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*-
* 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.
*/
/*
* Kernel loader for ELF objects.
*
* TODO: adjust kmem_alloc() calls to avoid needless fragmentation.
*/
#include "opt_modular.h"
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_kobj.c,v 1.22 2008/10/06 10:46:58 ad Exp $");
#define ELFSIZE ARCH_ELFSIZE
#include <sys/systm.h>
#include <sys/kobj.h>
#include <sys/errno.h>
#ifdef MODULAR
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/fcntl.h>
#include <sys/ksyms.h>
#include <sys/lkm.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <machine/stdarg.h>
#include <uvm/uvm_extern.h>
typedef struct {
void *addr;
Elf_Off size;
int flags;
int sec; /* Original section */
const char *name;
} progent_t;
typedef struct {
Elf_Rel *rel;
int nrel;
int sec;
size_t size;
} relent_t;
typedef struct {
Elf_Rela *rela;
int nrela;
int sec;
size_t size;
} relaent_t;
typedef enum kobjtype {
KT_UNSET,
KT_VNODE,
KT_MEMORY
} kobjtype_t;
struct kobj {
char ko_name[MAXLKMNAME];
kobjtype_t ko_type;
void *ko_source;
ssize_t ko_memsize;
vaddr_t ko_address; /* Relocation address */
Elf_Shdr *ko_shdr;
progent_t *ko_progtab;
relaent_t *ko_relatab;
relent_t *ko_reltab;
Elf_Sym *ko_symtab; /* Symbol table */
char *ko_strtab; /* String table */
char *ko_shstrtab; /* Section name string table */
size_t ko_size; /* Size of text/data/bss */
size_t ko_symcnt; /* Number of symbols */
size_t ko_strtabsz; /* Number of bytes in string table */
size_t ko_shstrtabsz; /* Number of bytes in scn str table */
size_t ko_shdrsz;
int ko_nrel;
int ko_nrela;
int ko_nprogtab;
bool ko_ksyms;
bool ko_loaded;
};
static int kobj_relocate(kobj_t, bool);
static void kobj_error(const char *, ...);
static int kobj_read(kobj_t, void **, size_t, off_t);
static int kobj_read_bits(kobj_t, void *, size_t, off_t);
static void kobj_jettison(kobj_t);
static void kobj_free(kobj_t, void *, size_t);
static void kobj_close(kobj_t);
static int kobj_load(kobj_t);
extern struct vm_map *lkm_map;
/*
* kobj_load_file:
*
* Load an object located in the file system.
*/
int
kobj_load_file(kobj_t *kop, const char *filename, const char *base,
bool autoload)
{
struct nameidata nd;
kauth_cred_t cred;
char *path;
int error;
kobj_t ko;
cred = kauth_cred_get();
ko = kmem_zalloc(sizeof(*ko), KM_SLEEP);
if (ko == NULL) {
return ENOMEM;
}
if (autoload) {
error = ENOENT;
} else {
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename);
error = vn_open(&nd, FREAD, 0);
}
if (error != 0) {
if (error != ENOENT) {
goto out;
}
path = PNBUF_GET();
snprintf(path, MAXPATHLEN - 1, "%s/%s/%s.kmod", base,
filename, filename);
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path);
error = vn_open(&nd, FREAD, 0);
if (error != 0) {
strlcat(path, ".o", MAXPATHLEN);
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path);
error = vn_open(&nd, FREAD, 0);
}
PNBUF_PUT(path);
if (error != 0) {
goto out;
}
}
out:
if (error != 0) {
kmem_free(ko, sizeof(*ko));
return error;
}
ko->ko_type = KT_VNODE;
ko->ko_source = nd.ni_vp;
*kop = ko;
return kobj_load(ko);
}
/*
* kobj_load_mem:
*
* Load an object already resident in memory. If size is not -1,
* the complete size of the object is known.
*/
int
kobj_load_mem(kobj_t *kop, void *base, ssize_t size)
{
kobj_t ko;
ko = kmem_zalloc(sizeof(*ko), KM_SLEEP);
if (ko == NULL) {
return ENOMEM;
}
ko->ko_type = KT_MEMORY;
ko->ko_source = base;
ko->ko_memsize = size;
*kop = ko;
return kobj_load(ko);
}
/*
* kobj_close:
*
* Close an open ELF object.
*/
static void
kobj_close(kobj_t ko)
{
if (ko->ko_source == NULL) {
return;
}
switch (ko->ko_type) {
case KT_VNODE:
VOP_UNLOCK(ko->ko_source, 0);
vn_close(ko->ko_source, FREAD, kauth_cred_get());
break;
case KT_MEMORY:
/* nothing */
break;
default:
panic("kobj_close: unknown type");
break;
}
ko->ko_source = NULL;
}
/*
* kobj_load:
*
* Load an ELF object and prepare to link into the running kernel
* image.
*/
static int
kobj_load(kobj_t ko)
{
Elf_Ehdr *hdr;
Elf_Shdr *shdr;
Elf_Sym *es;
vaddr_t mapbase;
size_t mapsize;
int error;
int symtabindex;
int symstrindex;
int nsym;
int pb, rl, ra;
int alignmask;
int i, j;
void *addr;
KASSERT(ko->ko_type != KT_UNSET);
KASSERT(ko->ko_source != NULL);
shdr = NULL;
mapsize = 0;
error = 0;
hdr = NULL;
/*
* Read the elf header from the file.
*/
error = kobj_read(ko, (void **)&hdr, sizeof(*hdr), 0);
if (error != 0)
goto out;
if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0) {
kobj_error("not an ELF object");
error = ENOEXEC;
goto out;
}
if (hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_version != EV_CURRENT) {
kobj_error("unsupported file version");
error = ENOEXEC;
goto out;
}
if (hdr->e_type != ET_REL) {
kobj_error("unsupported file type");
error = ENOEXEC;
goto out;
}
switch (hdr->e_machine) {
#if ELFSIZE == 32
ELF32_MACHDEP_ID_CASES
#else
ELF64_MACHDEP_ID_CASES
#endif
default:
kobj_error("unsupported machine");
error = ENOEXEC;
goto out;
}
ko->ko_nprogtab = 0;
ko->ko_shdr = 0;
ko->ko_nrel = 0;
ko->ko_nrela = 0;
/*
* Allocate and read in the section header.
*/
ko->ko_shdrsz = hdr->e_shnum * hdr->e_shentsize;
if (ko->ko_shdrsz == 0 || hdr->e_shoff == 0 ||
hdr->e_shentsize != sizeof(Elf_Shdr)) {
error = ENOEXEC;
goto out;
}
error = kobj_read(ko, (void **)&shdr, ko->ko_shdrsz, hdr->e_shoff);
if (error != 0) {
goto out;
}
ko->ko_shdr = shdr;
/*
* Scan the section header for information and table sizing.
*/
nsym = 0;
symtabindex = -1;
symstrindex = -1;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
ko->ko_nprogtab++;
break;
case SHT_SYMTAB:
nsym++;
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
ko->ko_nrel++;
break;
case SHT_RELA:
ko->ko_nrela++;
break;
case SHT_STRTAB:
break;
}
}
if (ko->ko_nprogtab == 0) {
kobj_error("file has no contents");
error = ENOEXEC;
goto out;
}
if (nsym != 1) {
/* Only allow one symbol table for now */
kobj_error("file has no valid symbol table");
error = ENOEXEC;
goto out;
}
if (symstrindex < 0 || symstrindex > hdr->e_shnum ||
shdr[symstrindex].sh_type != SHT_STRTAB) {
kobj_error("file has invalid symbol strings");
error = ENOEXEC;
goto out;
}
/*
* Allocate space for tracking the load chunks.
*/
if (ko->ko_nprogtab != 0) {
ko->ko_progtab = kmem_zalloc(ko->ko_nprogtab *
sizeof(*ko->ko_progtab), KM_SLEEP);
if (ko->ko_progtab == NULL) {
error = ENOMEM;
goto out;
}
}
if (ko->ko_nrel != 0) {
ko->ko_reltab = kmem_zalloc(ko->ko_nrel *
sizeof(*ko->ko_reltab), KM_SLEEP);
if (ko->ko_reltab == NULL) {
error = ENOMEM;
goto out;
}
}
if (ko->ko_nrela != 0) {
ko->ko_relatab = kmem_zalloc(ko->ko_nrela *
sizeof(*ko->ko_relatab), KM_SLEEP);
if (ko->ko_relatab == NULL) {
error = ENOMEM;
goto out;
}
}
if (symtabindex == -1) {
kobj_error("lost symbol table index");
goto out;
}
/*
* Allocate space for and load the symbol table.
*/
ko->ko_symcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym);
if (ko->ko_symcnt == 0) {
kobj_error("no symbol table");
goto out;
}
error = kobj_read(ko, (void **)&ko->ko_symtab,
ko->ko_symcnt * sizeof(Elf_Sym),
shdr[symtabindex].sh_offset);
if (error != 0) {
goto out;
}
/*
* Allocate space for and load the symbol strings.
*/
ko->ko_strtabsz = shdr[symstrindex].sh_size;
if (ko->ko_strtabsz == 0) {
kobj_error("no symbol strings");
goto out;
}
error = kobj_read(ko, (void *)&ko->ko_strtab, ko->ko_strtabsz,
shdr[symstrindex].sh_offset);
if (error != 0) {
goto out;
}
/*
* Do we have a string table for the section names?
*/
if (hdr->e_shstrndx != 0 && shdr[hdr->e_shstrndx].sh_size != 0 &&
shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) {
ko->ko_shstrtabsz = shdr[hdr->e_shstrndx].sh_size;
error = kobj_read(ko, (void *)&ko->ko_shstrtab,
shdr[hdr->e_shstrndx].sh_size,
shdr[hdr->e_shstrndx].sh_offset);
if (error != 0) {
goto out;
}
}
/*
* Size up code/data(progbits) and bss(nobits).
*/
alignmask = 0;
mapbase = 0;
for (i = 0; i < hdr->e_shnum; i++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
if (mapbase == 0)
mapbase = shdr[i].sh_offset;
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.
*/
if (mapsize == 0) {
kobj_error("no text/data/bss");
goto out;
}
if (ko->ko_type == KT_MEMORY) {
mapbase += (vaddr_t)ko->ko_source;
} else {
mapbase = uvm_km_alloc(lkm_map, round_page(mapsize),
0, UVM_KMF_WIRED | UVM_KMF_EXEC);
if (mapbase == 0) {
error = ENOMEM;
goto out;
}
}
ko->ko_address = mapbase;
ko->ko_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++) {
switch (shdr[i].sh_type) {
case SHT_PROGBITS:
case SHT_NOBITS:
alignmask = shdr[i].sh_addralign - 1;
if (ko->ko_type == KT_MEMORY) {
addr = (void *)(shdr[i].sh_offset +
(vaddr_t)ko->ko_source);
if (((vaddr_t)addr & alignmask) != 0) {
kobj_error("section %d not aligned\n",
i);
goto out;
}
} else {
mapbase += alignmask;
mapbase &= ~alignmask;
addr = (void *)mapbase;
mapbase += shdr[i].sh_size;
}
ko->ko_progtab[pb].addr = addr;
if (shdr[i].sh_type == SHT_PROGBITS) {
ko->ko_progtab[pb].name = "<<PROGBITS>>";
error = kobj_read_bits(ko, addr,
shdr[i].sh_size, shdr[i].sh_offset);
if (error != 0) {
goto out;
}
} else if (ko->ko_type == KT_MEMORY &&
shdr[i].sh_size != 0) {
kobj_error("non-loadable BSS section in "
"pre-loaded module");
error = EINVAL;
goto out;
} else {
ko->ko_progtab[pb].name = "<<NOBITS>>";
memset(addr, 0, shdr[i].sh_size);
}
ko->ko_progtab[pb].size = shdr[i].sh_size;
ko->ko_progtab[pb].sec = i;
if (ko->ko_shstrtab != NULL && shdr[i].sh_name != 0) {
ko->ko_progtab[pb].name =
ko->ko_shstrtab + shdr[i].sh_name;
}
/* Update all symbol values with the offset. */
for (j = 0; j < ko->ko_symcnt; j++) {
es = &ko->ko_symtab[j];
if (es->st_shndx != i) {
continue;
}
es->st_value += (Elf_Addr)addr;
}
pb++;
break;
case SHT_REL:
ko->ko_reltab[rl].size = shdr[i].sh_size;
ko->ko_reltab[rl].size -=
shdr[i].sh_size % sizeof(Elf_Rel);
if (ko->ko_reltab[rl].size != 0) {
ko->ko_reltab[rl].nrel =
shdr[i].sh_size / sizeof(Elf_Rel);
ko->ko_reltab[rl].sec = shdr[i].sh_info;
error = kobj_read(ko,
(void **)&ko->ko_reltab[rl].rel,
ko->ko_reltab[rl].size,
shdr[i].sh_offset);
if (error != 0) {
goto out;
}
}
rl++;
break;
case SHT_RELA:
ko->ko_relatab[ra].size = shdr[i].sh_size;
ko->ko_relatab[ra].size -=
shdr[i].sh_size % sizeof(Elf_Rela);
if (ko->ko_relatab[ra].size != 0) {
ko->ko_relatab[ra].nrela =
shdr[i].sh_size / sizeof(Elf_Rela);
ko->ko_relatab[ra].sec = shdr[i].sh_info;
error = kobj_read(ko,
(void **)&ko->ko_relatab[ra].rela,
shdr[i].sh_size,
shdr[i].sh_offset);
if (error != 0) {
goto out;
}
}
ra++;
break;
default:
break;
}
}
if (pb != ko->ko_nprogtab) {
panic("lost progbits");
}
if (rl != ko->ko_nrel) {
panic("lost rel");
}
if (ra != ko->ko_nrela) {
panic("lost rela");
}
if (ko->ko_type != KT_MEMORY && mapbase != ko->ko_address + mapsize) {
panic("mapbase 0x%lx != address %lx + mapsize %ld (0x%lx)\n",
(long)mapbase, (long)ko->ko_address, (long)mapsize,
(long)ko->ko_address + mapsize);
}
/*
* Perform local relocations only. Relocations relating to global
* symbols will be done by kobj_affix().
*/
error = kobj_relocate(ko, true);
out:
if (hdr != NULL) {
kobj_free(ko, hdr, sizeof(*hdr));
}
kobj_close(ko);
if (error != 0) {
kobj_unload(ko);
}
return error;
}
/*
* kobj_unload:
*
* Unload an object previously loaded by kobj_load().
*/
void
kobj_unload(kobj_t ko)
{
int error;
kobj_close(ko);
kobj_jettison(ko);
/*
* Notify MD code that a module has been unloaded.
*/
if (ko->ko_loaded) {
error = kobj_machdep(ko, (void *)ko->ko_address, ko->ko_size,
false);
if (error != 0) {
kobj_error("machine dependent deinit failed");
}
}
if (ko->ko_address != 0 && ko->ko_type != KT_MEMORY) {
uvm_km_free(lkm_map, ko->ko_address, round_page(ko->ko_size),
UVM_KMF_WIRED);
}
if (ko->ko_ksyms == true) {
ksyms_delsymtab(ko->ko_name);
}
if (ko->ko_symtab != NULL) {
kobj_free(ko, ko->ko_symtab, ko->ko_symcnt * sizeof(Elf_Sym));
}
if (ko->ko_strtab != NULL) {
kobj_free(ko, ko->ko_strtab, ko->ko_strtabsz);
}
if (ko->ko_progtab != NULL) {
kobj_free(ko, ko->ko_progtab, ko->ko_nprogtab *
sizeof(*ko->ko_progtab));
ko->ko_progtab = NULL;
}
if (ko->ko_shstrtab) {
kobj_free(ko, ko->ko_shstrtab, ko->ko_shstrtabsz);
ko->ko_shstrtab = NULL;
}
kmem_free(ko, sizeof(*ko));
}
/*
* kobj_stat:
*
* Return size and load address of an object.
*/
void
kobj_stat(kobj_t ko, vaddr_t *address, size_t *size)
{
if (address != NULL) {
*address = ko->ko_address;
}
if (size != NULL) {
*size = ko->ko_size;
}
}
/*
* kobj_affix:
*
* Set an object's name and perform global relocs. May only be
* called after the module and any requisite modules are loaded.
*/
int
kobj_affix(kobj_t ko, const char *name)
{
int error;
KASSERT(ko->ko_ksyms == false);
KASSERT(ko->ko_loaded == false);
strlcpy(ko->ko_name, name, sizeof(ko->ko_name));
/* Now that we know the name, register the symbol table. */
error = ksyms_addsymtab(ko->ko_name, ko->ko_symtab, ko->ko_symcnt *
sizeof(Elf_Sym), ko->ko_strtab, ko->ko_strtabsz);
if (error != 0) {
kobj_error("unable to register module symbol table");
} else {
ko->ko_ksyms = true;
/* Now do global relocations. */
error = kobj_relocate(ko, false);
}
/* Jettison unneeded memory post-link. */
kobj_jettison(ko);
/* Notify MD code that a module has been loaded. */
if (error == 0) {
error = kobj_machdep(ko, (void *)ko->ko_address, ko->ko_size,
true);
if (error != 0) {
kobj_error("machine dependent init failed");
}
ko->ko_loaded = true;
}
/* If there was an error, destroy the whole object. */
if (error != 0) {
kobj_unload(ko);
}
return error;
}
/*
* kobj_find_section:
*
* Given a section name, search the loaded object and return
* virtual address if present and loaded.
*/
int
kobj_find_section(kobj_t ko, const char *name, void **addr, size_t *size)
{
int i;
KASSERT(ko->ko_progtab != NULL);
for (i = 0; i < ko->ko_nprogtab; i++) {
if (strcmp(ko->ko_progtab[i].name, name) == 0) {
if (addr != NULL) {
*addr = ko->ko_progtab[i].addr;
}
if (size != NULL) {
*size = ko->ko_progtab[i].size;
}
return 0;
}
}
return ENOENT;
}
/*
* kobj_jettison:
*
* Release object data not needed after performing relocations.
*/
static void
kobj_jettison(kobj_t ko)
{
int i;
for (i = 0; i < ko->ko_nrel; i++) {
if (ko->ko_reltab[i].rel) {
kobj_free(ko, ko->ko_reltab[i].rel,
ko->ko_reltab[i].size);
}
}
for (i = 0; i < ko->ko_nrela; i++) {
if (ko->ko_relatab[i].rela) {
kobj_free(ko, ko->ko_relatab[i].rela,
ko->ko_relatab[i].size);
}
}
if (ko->ko_reltab != NULL) {
kobj_free(ko, ko->ko_reltab, ko->ko_nrel *
sizeof(*ko->ko_reltab));
ko->ko_reltab = NULL;
ko->ko_nrel = 0;
}
if (ko->ko_relatab != NULL) {
kobj_free(ko, ko->ko_relatab, ko->ko_nrela *
sizeof(*ko->ko_relatab));
ko->ko_relatab = NULL;
ko->ko_nrela = 0;
}
if (ko->ko_shdr != NULL) {
kobj_free(ko, ko->ko_shdr, ko->ko_shdrsz);
ko->ko_shdr = NULL;
}
}
/*
* kobj_sym_lookup:
*
* Symbol lookup function to be used when the symbol index
* is known (ie during relocation).
*/
uintptr_t
kobj_sym_lookup(kobj_t ko, uintptr_t symidx)
{
const Elf_Sym *sym;
const char *symbol;
int error;
u_long addr;
/* Don't even try to lookup the symbol if the index is bogus. */
if (symidx >= ko->ko_symcnt)
return 0;
sym = ko->ko_symtab + symidx;
/* Quick answer if there is a definition included. */
if (sym->st_shndx != SHN_UNDEF) {
return sym->st_value;
}
/* 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? */
kobj_error("local symbol undefined");
return 0;
case STB_GLOBAL:
/* Relative to Data or Function name */
symbol = ko->ko_strtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
if (*symbol == 0) {
kobj_error("bad symbol name");
return 0;
}
error = ksyms_getval(NULL, symbol, &addr, KSYMS_ANY);
if (error != 0) {
kobj_error("symbol `%s' not found", symbol);
return (uintptr_t)0;
}
return (uintptr_t)addr;
case STB_WEAK:
kobj_error("weak symbols not supported\n");
return 0;
default:
return 0;
}
}
/*
* kobj_findbase:
*
* Return base address of the given section.
*/
static uintptr_t
kobj_findbase(kobj_t ko, int sec)
{
int i;
for (i = 0; i < ko->ko_nprogtab; i++) {
if (sec == ko->ko_progtab[i].sec) {
return (uintptr_t)ko->ko_progtab[i].addr;
}
}
return 0;
}
/*
* kobj_relocate:
*
* Resolve relocations for the loaded object.
*/
static int
kobj_relocate(kobj_t ko, bool local)
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const Elf_Sym *sym;
uintptr_t base;
int i, error;
uintptr_t symidx;
/*
* Perform relocations without addend if there are any.
*/
for (i = 0; i < ko->ko_nrel; i++) {
rel = ko->ko_reltab[i].rel;
if (rel == NULL) {
continue;
}
rellim = rel + ko->ko_reltab[i].nrel;
base = kobj_findbase(ko, ko->ko_reltab[i].sec);
if (base == 0) {
panic("lost base for e_reltab");
}
for (; rel < rellim; rel++) {
symidx = ELF_R_SYM(rel->r_info);
if (symidx >= ko->ko_symcnt) {
continue;
}
sym = ko->ko_symtab + symidx;
if (local != (ELF_ST_BIND(sym->st_info) == STB_LOCAL)) {
continue;
}
error = kobj_reloc(ko, base, rel, false, local);
if (error != 0) {
return ENOENT;
}
}
}
/*
* Perform relocations with addend if there are any.
*/
for (i = 0; i < ko->ko_nrela; i++) {
rela = ko->ko_relatab[i].rela;
if (rela == NULL) {
continue;
}
relalim = rela + ko->ko_relatab[i].nrela;
base = kobj_findbase(ko, ko->ko_relatab[i].sec);
if (base == 0) {
panic("lost base for e_relatab");
}
for (; rela < relalim; rela++) {
symidx = ELF_R_SYM(rela->r_info);
if (symidx >= ko->ko_symcnt) {
continue;
}
sym = ko->ko_symtab + symidx;
if (local != (ELF_ST_BIND(sym->st_info) == STB_LOCAL)) {
continue;
}
error = kobj_reloc(ko, base, rela, true, local);
if (error != 0) {
return ENOENT;
}
}
}
return 0;
}
/*
* kobj_error:
*
* Utility function: log an error.
*/
static void
kobj_error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
printf("WARNING: linker error: ");
vprintf(fmt, ap);
printf("\n");
va_end(ap);
}
/*
* kobj_read:
*
* Utility function: read from the object.
*/
static int
kobj_read(kobj_t ko, void **basep, size_t size, off_t off)
{
size_t resid;
void *base;
int error;
KASSERT(ko->ko_source != NULL);
switch (ko->ko_type) {
case KT_VNODE:
base = kmem_alloc(size, KM_SLEEP);
if (base == NULL) {
error = ENOMEM;
break;
}
error = vn_rdwr(UIO_READ, ko->ko_source, base, size, off,
UIO_SYSSPACE, IO_NODELOCKED, curlwp->l_cred, &resid,
curlwp);
if (error == 0 && resid != 0) {
error = EINVAL;
}
if (error != 0) {
kmem_free(base, size);
base = NULL;
}
break;
case KT_MEMORY:
if (ko->ko_memsize != -1 && off + size > ko->ko_memsize) {
kobj_error("kobj_read: preloaded object short");
error = EINVAL;
base = NULL;
} else {
base = (uint8_t *)ko->ko_source + off;
error = 0;
}
break;
default:
panic("kobj_read: invalid type");
}
*basep = base;
return error;
}
/*
* kobj_read_bits:
*
* Utility function: load a section from the object.
*/
static int
kobj_read_bits(kobj_t ko, void *base, size_t size, off_t off)
{
size_t resid;
int error;
KASSERT(ko->ko_source != NULL);
switch (ko->ko_type) {
case KT_VNODE:
KASSERT((uintptr_t)base >= (uintptr_t)ko->ko_address);
KASSERT((uintptr_t)base + size <=
(uintptr_t)ko->ko_address + ko->ko_size);
error = vn_rdwr(UIO_READ, ko->ko_source, base, size, off,
UIO_SYSSPACE, IO_NODELOCKED, curlwp->l_cred, &resid,
curlwp);
if (error == 0 && resid != 0) {
error = EINVAL;
}
break;
case KT_MEMORY:
if (ko->ko_memsize != -1 && off + size > ko->ko_memsize) {
kobj_error("kobj_read_bits: preloaded object short");
error = EINVAL;
} else if ((uint8_t *)base != (uint8_t *)ko->ko_source + off) {
kobj_error("kobj_read_bits: object not aligned");
kobj_error("source=%p base=%p off=%d size=%zd",
ko->ko_source, base, (int)off, size);
error = EINVAL;
} else {
/* Nothing to do. Loading in-situ. */
error = 0;
}
break;
default:
panic("kobj_read: invalid type");
}
return error;
}
/*
* kobj_free:
*
* Utility function: free memory if it was allocated from the heap.
*/
static void
kobj_free(kobj_t ko, void *base, size_t size)
{
if (ko->ko_type != KT_MEMORY)
kmem_free(base, size);
}
#else /* MODULAR */
int
kobj_load_file(kobj_t *kop, const char *name, const char *base, bool autoload)
{
return ENOSYS;
}
int
kobj_load_mem(kobj_t *kop, void *base, ssize_t size)
{
return ENOSYS;
}
void
kobj_unload(kobj_t ko)
{
panic("not modular");
}
void
kobj_stat(kobj_t ko, vaddr_t *base, size_t *size)
{
panic("not modular");
}
int
kobj_affix(kobj_t ko, const char *name)
{
panic("not modular");
}
int
kobj_find_section(kobj_t ko, const char *name, void **addr, size_t *size)
{
panic("not modular");
}
#endif /* MODULAR */
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