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opnsense-src/sys/kern/link_elf_obj.c
Zhenlei Huang 894efae09d sysctl(9): Enable vnet sysctl variables to be loader tunable 
Complete phase two of 3da1cf1e88.

In 3da1cf1e88, the meaning of the flag CTLFLAG_TUN is extended to
automatically check if there is a kernel environment variable which
shall initialize the SYSCTL during early boot. It works for all SYSCTL
types both statically and dynamically created ones, except for the
SYSCTLs which belong to VNETs.

This change extends the meaning further, to allow it also works for
the SYSCTLs which belong to VNETs. A typical usage is
```
VNET_DEFINE_STATIC(int, foo) = 0;
SYSCTL_INT(_net, OID_AUTO, foo, CTLFLAG_RWTUN | CTLFLAG_VNET,
    &VNET_NAME(foo), 0, "Description of the foo loader tunable");
```

Note that the implementation has a limitation. It behaves the same way
as that of non-vnet loader tunables. That is, after the kernel or modules
being initialized, any changes (e.g. via kenv) to kernel environment
variable will not affect the corresponding vnet variable of subsequently
created VNETs. To overcome it, we can use TUNABLE_XXX_FETCH to fetch
the kernel environment variable into those vnet variables during vnet
constructing.

This change will fix the following SYSCTLs those belong to VNETs and
have CTLFLAG_TUN flag:
```
net.add_addr_allfibs
net.bpf.optimize_writers
net.inet.tcp.fastopen.ccache_buckets
net.link.bridge.inherit_mac
net.link.bridge.ipfw_arp
net.link.bridge.log_stp
net.link.bridge.pfil_bridge
net.link.bridge.pfil_local_phys
net.link.bridge.pfil_member
net.link.bridge.pfil_onlyip
net.link.lagg.default_use_flowid
net.link.lagg.default_use_numa
net.link.lagg.default_flowid_shift
net.link.lagg.lacp.debug
net.link.lagg.lacp.default_strict_mode
```

Although the following vnet SYSCTLs have CTLFLAG_TUN flag, theirs
values are re-fetched via TUNABLE_XXX_FETCH, thus are not affected
by this change.
```
net.inet.ip.reass_hashsize
net.inet.tcp.hostcache.cachelimit
net.inet.tcp.hostcache.hashsize
net.inet.tcp.hostcache.bucketlimit
net.inet.tcp.syncache.bucketlimit
net.inet.tcp.syncache.cachelimit
net.inet.tcp.syncache.hashsize
net.key.spdcache.maxentries
net.key.spdcache.threshold
```

In memoriam:	hselasky
Discussed with:	hselasky, glebius
Fixes:		3da1cf1e88 Extend the meaning of the CTLFLAG_TUN flag ...
MFC after:	2 weeks
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D39638

(cherry picked from commit 110113bc086f5df1a9b6547edb1ab0cec698c55c)
2025-01-24 23:35:49 +08:00

1913 lines
49 KiB
C
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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* 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>
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/linker.h>
#include <sys/mutex.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/sysctl.h>
#include <sys/vnode.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/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <sys/link_elf.h>
#ifdef DDB_CTF
#include <contrib/zlib/zlib.h>
#endif
#include "linker_if.h"
typedef struct {
void *addr;
Elf_Off size;
int flags; /* Section flags. */
int sec; /* Original section number. */
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;
u_int nprogtab;
Elf_relaent *relatab;
u_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_lookup_debug_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_debug_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, bool);
static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long link_elf_strtab_get(linker_file_t, caddr_t *);
#ifdef VIMAGE
static void link_elf_propagate_vnets(linker_file_t);
#endif
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_lookup_debug_symbol, link_elf_lookup_debug_symbol),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_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),
#ifdef VIMAGE
KOBJMETHOD(linker_propagate_vnets, link_elf_propagate_vnets),
#endif
KOBJMETHOD_END
};
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 bool link_elf_obj_leak_locals = true;
SYSCTL_BOOL(_debug, OID_AUTO, link_elf_obj_leak_locals,
CTLFLAG_RWTUN, &link_elf_obj_leak_locals, 0,
"Allow local symbols to participate in global module symbol resolution");
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, NULL);
static void
link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end,
vm_prot_t prot)
{
int error __unused;
KASSERT(start <= end && start >= (vm_offset_t)ef->address &&
end <= round_page((vm_offset_t)ef->address + ef->lf.size),
("link_elf_protect_range: invalid range %#jx-%#jx",
(uintmax_t)start, (uintmax_t)end));
if (start == end)
return;
if (ef->preloaded) {
#ifdef __amd64__
error = pmap_change_prot(start, end - start, prot);
KASSERT(error == 0,
("link_elf_protect_range: pmap_change_prot() returned %d",
error));
#endif
return;
}
error = vm_map_protect(kernel_map, start, end, prot, 0,
VM_MAP_PROTECT_SET_PROT);
KASSERT(error == KERN_SUCCESS,
("link_elf_protect_range: vm_map_protect() returned %d", error));
}
/*
* Restrict permissions on linker file memory based on section flags.
* Sections need not be page-aligned, so overlap within a page is possible.
*/
static void
link_elf_protect(elf_file_t ef)
{
vm_offset_t end, segend, segstart, start;
vm_prot_t gapprot, prot, segprot;
int i;
/*
* If the file was preloaded, the last page may contain other preloaded
* data which may need to be writeable. ELF files are always
* page-aligned, but other preloaded data, such as entropy or CPU
* microcode may be loaded with a smaller alignment.
*/
gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ;
start = end = (vm_offset_t)ef->address;
prot = VM_PROT_READ;
for (i = 0; i < ef->nprogtab; i++) {
/*
* VNET and DPCPU sections have their memory allocated by their
* respective subsystems.
*/
if (ef->progtab[i].name != NULL && (
#ifdef VIMAGE
strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 ||
#endif
strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0))
continue;
segstart = trunc_page((vm_offset_t)ef->progtab[i].addr);
segend = round_page((vm_offset_t)ef->progtab[i].addr +
ef->progtab[i].size);
segprot = VM_PROT_READ;
if ((ef->progtab[i].flags & SHF_WRITE) != 0)
segprot |= VM_PROT_WRITE;
if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0)
segprot |= VM_PROT_EXECUTE;
if (end <= segstart) {
/*
* Case 1: there is no overlap between the previous
* segment and this one. Apply protections to the
* previous segment, and protect the gap between the
* previous and current segments, if any.
*/
link_elf_protect_range(ef, start, end, prot);
link_elf_protect_range(ef, end, segstart, gapprot);
start = segstart;
end = segend;
prot = segprot;
} else if (start < segstart && end == segend) {
/*
* Case 2: the current segment is a subrange of the
* previous segment. Apply protections to the
* non-overlapping portion of the previous segment.
*/
link_elf_protect_range(ef, start, segstart, prot);
start = segstart;
prot |= segprot;
} else if (end < segend) {
/*
* Case 3: there is partial overlap between the previous
* and current segments. Apply protections to the
* non-overlapping portion of the previous segment, and
* then the overlap, which must use the union of the two
* segments' protections.
*/
link_elf_protect_range(ef, start, segstart, prot);
link_elf_protect_range(ef, segstart, end,
prot | segprot);
start = end;
end = segend;
prot = segprot;
} else {
/*
* Case 4: the two segments reside in the same page.
*/
prot |= segprot;
}
}
/*
* Fix up the last unprotected segment and trailing data.
*/
link_elf_protect_range(ef, start, end, prot);
link_elf_protect_range(ef, end,
round_page((vm_offset_t)ef->address + ef->lf.size), gapprot);
}
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
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
/* Ignore sections not loaded by the loader. */
if (shdr[i].sh_addr == 0)
break;
ef->nprogtab++;
break;
case SHT_SYMTAB:
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
/*
* Ignore relocation tables for sections not
* loaded by the loader.
*/
if (shdr[shdr[i].sh_info].sh_addr == 0)
break;
ef->nreltab++;
break;
case SHT_RELA:
if (shdr[shdr[i].sh_info].sh_addr == 0)
break;
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
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if (shdr[i].sh_addr == 0)
break;
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 if (shdr[i].sh_type == SHT_INIT_ARRAY)
ef->progtab[pb].name = "<<INIT_ARRAY>>";
else if (shdr[i].sh_type == SHT_FINI_ARRAY)
ef->progtab[pb].name = "<<FINI_ARRAY>>";
else
ef->progtab[pb].name = "<<NOBITS>>";
ef->progtab[pb].size = shdr[i].sh_size;
ef->progtab[pb].flags = shdr[i].sh_flags;
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) {
printf("%s: pcpu module space is out "
"of space; cannot allocate %#jx "
"for %s\n", __func__,
(uintmax_t)shdr[i].sh_size,
filename);
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) {
printf("%s: vnet module space is out "
"of space; cannot allocate %#jx "
"for %s\n", __func__,
(uintmax_t)shdr[i].sh_size,
filename);
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") == 0) ||
shdr[i].sh_type == SHT_INIT_ARRAY) {
if (lf->ctors_addr != 0) {
printf(
"%s: multiple ctor sections in %s\n",
__func__, filename);
} else {
lf->ctors_addr = ef->progtab[pb].addr;
lf->ctors_size = shdr[i].sh_size;
}
} else if ((ef->progtab[pb].name != NULL &&
strcmp(ef->progtab[pb].name, ".dtors") == 0) ||
shdr[i].sh_type == SHT_FINI_ARRAY) {
if (lf->dtors_addr != 0) {
printf(
"%s: multiple dtor sections in %s\n",
__func__, filename);
} else {
lf->dtors_addr = ef->progtab[pb].addr;
lf->dtors_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:
if (shdr[shdr[i].sh_info].sh_addr == 0)
break;
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:
if (shdr[shdr[i].sh_info].sh_addr == 0)
break;
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;
}
/*
* The file needs to be writeable and executable while applying
* relocations. Mapping protections are applied once relocation
* processing is complete.
*/
link_elf_protect_range(ef, (vm_offset_t)ef->address,
round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL);
/* Local intra-module relocations */
error = link_elf_reloc_local(lf, false);
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_cbs(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 void
link_elf_invoke_ctors(linker_file_t lf)
{
KASSERT(lf->ctors_invoked == LF_NONE,
("%s: file %s ctor state %d",
__func__, lf->filename, lf->ctors_invoked));
link_elf_invoke_cbs(lf->ctors_addr, lf->ctors_size);
lf->ctors_invoked = LF_CTORS;
}
static void
link_elf_invoke_dtors(linker_file_t lf)
{
KASSERT(lf->ctors_invoked != LF_DTORS,
("%s: file %s ctor state %d",
__func__, lf->filename, lf->ctors_invoked));
if (lf->ctors_invoked == LF_CTORS) {
link_elf_invoke_cbs(lf->dtors_addr, lf->dtors_size);
lf->ctors_invoked = LF_DTORS;
}
}
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);
#if defined(__i386__) || defined(__amd64__)
/* Now ifuncs. */
error = link_elf_reloc_local(lf, true);
if (error != 0)
return (error);
#endif
/* Apply protections now that relocation processing is complete. */
link_elf_protect(ef);
link_elf_invoke_ctors(lf);
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);
flags = FREAD;
error = vn_open(nd, &flags, 0, NULL);
if (error) {
free(nd, M_TEMP);
return error;
}
NDFREE_PNBUF(nd);
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
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
ef->nprogtab++;
break;
case SHT_SYMTAB:
nsym++;
symtabindex = i;
symstrindex = shdr[i].sh_link;
break;
case SHT_REL:
/*
* Ignore relocation tables for unallocated
* sections.
*/
if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
break;
ef->nreltab++;
break;
case SHT_RELA:
if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
break;
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 must have exactly one 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;
}
/* 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
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
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_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize),
VM_PROT_ALL, 0, thread0.td_ucred);
if (ef->object == NULL) {
error = ENOMEM;
goto out;
}
#if VM_NRESERVLEVEL > 0
vm_object_color(ef->object, 0);
#endif
/*
* 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.
*
* Protections will be restricted once relocations are applied.
*/
#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 != KERN_SUCCESS) {
vm_object_deallocate(ef->object);
ef->object = NULL;
error = ENOMEM;
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
case SHT_INIT_ARRAY:
case SHT_FINI_ARRAY:
if ((shdr[i].sh_flags & SHF_ALLOC) == 0)
break;
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") ||
shdr[i].sh_type == SHT_INIT_ARRAY) {
if (lf->ctors_addr != 0) {
printf(
"%s: multiple ctor sections in %s\n",
__func__, filename);
} else {
lf->ctors_addr =
(caddr_t)mapbase;
lf->ctors_size =
shdr[i].sh_size;
}
} else if (!strcmp(ef->progtab[pb].name,
".dtors") ||
shdr[i].sh_type == SHT_FINI_ARRAY) {
if (lf->dtors_addr != 0) {
printf(
"%s: multiple dtor sections in %s\n",
__func__, filename);
} else {
lf->dtors_addr =
(caddr_t)mapbase;
lf->dtors_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);
if (ef->progtab[pb].addr == NULL) {
printf("%s: pcpu module space is out "
"of space; cannot allocate %#jx "
"for %s\n", __func__,
(uintmax_t)shdr[i].sh_size,
filename);
}
}
#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);
if (ef->progtab[pb].addr == NULL) {
printf("%s: vnet module space is out "
"of space; cannot allocate %#jx "
"for %s\n", __func__,
(uintmax_t)shdr[i].sh_size,
filename);
}
}
#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].flags = shdr[i].sh_flags;
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:
if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
break;
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:
if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0)
break;
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, false);
if (error != 0)
goto out;
/* Pull in dependencies */
VOP_UNLOCK(nd->ni_vp);
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;
#if defined(__i386__) || defined(__amd64__)
/* Now ifuncs. */
error = link_elf_reloc_local(lf, true);
if (error != 0)
goto out;
#endif
link_elf_protect(ef);
link_elf_invoke_ctors(lf);
*result = lf;
out:
VOP_UNLOCK(nd->ni_vp);
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;
u_int i;
link_elf_invoke_dtors(file);
/* 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->pathname != NULL)
preload_delete_name(file->pathname);
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 != NULL)
vm_map_remove(kernel_map, (vm_offset_t)ef->address,
(vm_offset_t)ef->address + ptoa(ef->object->size));
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_file1(elf_file_t ef, bool ifuncs)
{
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_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
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_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
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
relocate_file(elf_file_t ef)
{
int error;
error = relocate_file1(ef, false);
if (error == 0)
error = relocate_file1(ef, true);
return (error);
}
static int
link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym,
bool see_local)
{
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) {
if (see_local ||
ELF_ST_BIND(symp->st_info) == STB_GLOBAL) {
*sym = (c_linker_sym_t) symp;
return (0);
}
return (ENOENT);
}
}
return (ENOENT);
}
static int
link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym)
{
return (link_elf_lookup_symbol1(lf, name, sym,
link_elf_obj_leak_locals));
}
static int
link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
c_linker_sym_t *sym)
{
return (link_elf_lookup_symbol1(lf, name, sym, true));
}
static int
link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval, bool see_local)
{
elf_file_t ef;
const Elf_Sym *es;
caddr_t val;
ef = (elf_file_t) lf;
es = (const Elf_Sym*) sym;
val = (caddr_t)es->st_value;
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL)
return (ENOENT);
symval->name = ef->ddbstrtab + es->st_name;
val = (caddr_t)es->st_value;
if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
val = ((caddr_t (*)(void))val)();
symval->value = val;
symval->size = es->st_size;
return (0);
}
return (ENOENT);
}
static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
return (link_elf_symbol_values1(lf, sym, symval,
link_elf_obj_leak_locals));
}
static int
link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
return (link_elf_symbol_values1(lf, sym, symval, true));
}
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 ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
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 ||
ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = link_elf_debug_symbol_values(file,
(c_linker_sym_t)symp, &symval);
if (error == 0)
error = callback(file, i, &symval, opaque);
if (error != 0)
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) {
res1 = (Elf_Addr)sym->st_value;
if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC)
res1 = ((Elf_Addr (*)(void))res1)();
*res = res1;
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, bool ifuncs)
{
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;
if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
elf_is_ifunc_reloc(rel->r_info)) != ifuncs)
continue;
if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL,
elf_obj_lookup) != 0)
return (ENOEXEC);
}
}
/* 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;
if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC ||
elf_is_ifunc_reloc(rela->r_info)) != ifuncs)
continue;
if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA,
elf_obj_lookup) != 0)
return (ENOEXEC);
}
}
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);
}
#ifdef VIMAGE
static void
link_elf_propagate_vnets(linker_file_t lf)
{
elf_file_t ef = (elf_file_t) lf;
if (ef->progtab) {
for (int 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, VNET_SETNAME) == 0) {
vnet_data_copy(ef->progtab[i].addr,
ef->progtab[i].size);
break;
}
}
}
}
#endif
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