NetBSD-5.0.2/sys/kern/kern_ksyms.c
/* $NetBSD: kern_ksyms.c,v 1.41.4.1 2009/03/31 23:23:15 snj Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software developed for The NetBSD Foundation
* by Andrew Doran.
*
* 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) 2001, 2003 Anders Magnusson (ragge@ludd.luth.se).
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
/*
* Code to deal with in-kernel symbol table management + /dev/ksyms.
*
* For each loaded module the symbol table info is kept track of by a
* struct, placed in a circular list. The first entry is the kernel
* symbol table.
*/
/*
* TODO:
*
* Consider replacing patricia tree with simpler binary search
* for symbol tables.
*
* Add support for mmap, poll.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.41.4.1 2009/03/31 23:23:15 snj Exp $");
#ifdef _KERNEL
#include "opt_ddb.h"
#include "opt_ddbparam.h" /* for SYMTAB_SPACE */
#endif
#define _KSYMS_PRIVATE
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/queue.h>
#include <sys/exec.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/module.h>
#include <sys/atomic.h>
#include <sys/ksyms.h>
#include <lib/libkern/libkern.h>
#ifdef DDB
#include <ddb/db_output.h>
#endif
#include "ksyms.h"
static int ksyms_maxlen;
static bool ksyms_isopen;
static bool ksyms_initted;
static struct ksyms_hdr ksyms_hdr;
static kmutex_t ksyms_lock;
void ksymsattach(int);
static void ksyms_hdr_init(void *);
static void ksyms_sizes_calc(void);
#ifdef KSYMS_DEBUG
#define FOLLOW_CALLS 1
#define FOLLOW_MORE_CALLS 2
#define FOLLOW_DEVKSYMS 4
static int ksyms_debug;
#endif
#ifdef SYMTAB_SPACE
#define SYMTAB_FILLER "|This is the symbol table!"
char db_symtab[SYMTAB_SPACE] = SYMTAB_FILLER;
int db_symtabsize = SYMTAB_SPACE;
#endif
int ksyms_symsz;
int ksyms_strsz;
TAILQ_HEAD(, ksyms_symtab) ksyms_symtabs =
TAILQ_HEAD_INITIALIZER(ksyms_symtabs);
static struct ksyms_symtab kernel_symtab;
/*
* Patricia-tree-based lookup structure for the in-kernel global symbols.
* Based on a design by Mikael Sundstrom, msm@sm.luth.se.
*/
struct ptree {
int16_t bitno;
int16_t lr[2];
} *symb;
static int16_t baseidx;
static int treex = 1;
#define P_BIT(key, bit) ((key[bit >> 3] >> (bit & 7)) & 1)
#define STRING(idx) (kernel_symtab.sd_symstart[idx].st_name + \
kernel_symtab.sd_strstart)
static int
ksyms_verify(void *symstart, void *strstart)
{
#if defined(DIAGNOSTIC) || defined(DEBUG)
if (symstart == NULL)
printf("ksyms: Symbol table not found\n");
if (strstart == NULL)
printf("ksyms: String table not found\n");
if (symstart == NULL || strstart == NULL)
printf("ksyms: Perhaps the kernel is stripped?\n");
#endif
if (symstart == NULL || strstart == NULL)
return 0;
KASSERT(symstart <= strstart);
return 1;
}
/*
* Walk down the tree until a terminal node is found.
*/
static int
symbol_traverse(const char *key)
{
int16_t nb, rbit = baseidx;
while (rbit > 0) {
nb = symb[rbit].bitno;
rbit = symb[rbit].lr[P_BIT(key, nb)];
}
return -rbit;
}
static int
ptree_add(char *key, int val)
{
int idx;
int nix, cix, bit, rbit, sb, lastrbit, svbit = 0, ix;
char *m, *k;
if (baseidx == 0) {
baseidx = -val;
return 0; /* First element */
}
/* Get string to match against */
idx = symbol_traverse(key);
/* Find first mismatching bit */
m = STRING(idx);
k = key;
if (strcmp(m, k) == 0)
return 1;
for (cix = 0; *m && *k && *m == *k; m++, k++, cix += 8)
;
ix = ffs((int)*m ^ (int)*k) - 1;
cix += ix;
/* Create new node */
nix = treex++;
bit = P_BIT(key, cix);
symb[nix].bitno = cix;
symb[nix].lr[bit] = -val;
/* Find where to insert node */
rbit = baseidx;
lastrbit = 0;
for (;;) {
if (rbit < 0)
break;
sb = symb[rbit].bitno;
if (sb > cix)
break;
if (sb == cix)
printf("symb[rbit].bitno == cix!!!\n");
lastrbit = rbit;
svbit = P_BIT(key, sb);
rbit = symb[rbit].lr[svbit];
}
/* Do the actual insertion */
if (lastrbit == 0) {
/* first element */
symb[nix].lr[!bit] = baseidx;
baseidx = nix;
} else {
symb[nix].lr[!bit] = rbit;
symb[lastrbit].lr[svbit] = nix;
}
return 0;
}
static int
ptree_find(const char *key)
{
int idx;
if (baseidx == 0)
return 0;
idx = symbol_traverse(key);
if (strcmp(key, STRING(idx)) == 0)
return idx;
return 0;
}
static void
ptree_gen(char *off, struct ksyms_symtab *tab)
{
Elf_Sym *sym;
int i, nsym;
if (off != NULL)
symb = (struct ptree *)ALIGN(off);
else
symb = malloc((tab->sd_symsize/sizeof(Elf_Sym)) *
sizeof(struct ptree), M_DEVBUF, M_WAITOK);
symb--; /* sym index won't be 0 */
sym = tab->sd_symstart;
if ((nsym = tab->sd_symsize/sizeof(Elf_Sym)) > INT16_MAX) {
printf("Too many symbols for tree, skipping %d symbols\n",
nsym-INT16_MAX);
nsym = INT16_MAX;
}
for (i = 1; i < nsym; i++) {
if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
continue;
ptree_add(tab->sd_strstart+sym[i].st_name, i);
if (tab->sd_minsym == NULL ||
sym[i].st_value < tab->sd_minsym->st_value)
tab->sd_minsym = &sym[i];
if (tab->sd_maxsym == NULL ||
sym[i].st_value > tab->sd_maxsym->st_value)
tab->sd_maxsym = &sym[i];
}
}
/*
* Finds a certain symbol name in a certain symbol table.
*/
static Elf_Sym *
findsym(const char *name, struct ksyms_symtab *table)
{
Elf_Sym *start = table->sd_symstart;
int i, sz = table->sd_symsize/sizeof(Elf_Sym);
char *np;
char *realstart = table->sd_strstart - table->sd_usroffset;
if (table == &kernel_symtab && (i = ptree_find(name)) != 0)
return &start[i];
for (i = 0; i < sz; i++) {
np = realstart + start[i].st_name;
if (name[0] == np[0] && name[1] == np[1] &&
strcmp(name, np) == 0)
return &start[i];
}
return NULL;
}
/*
* The "attach" is in reality done in ksyms_init().
*/
void
ksymsattach(int arg)
{
if (baseidx == 0)
ptree_gen(0, &kernel_symtab);
}
/*
* Add a symbol table.
* This is intended for use when the symbol table and its corresponding
* string table are easily available. If they are embedded in an ELF
* image, use addsymtab_elf() instead.
*
* name - Symbol's table name.
* symstart, symsize - Address and size of the symbol table.
* strstart, strsize - Address and size of the string table.
* tab - Symbol table to be updated with this information.
* newstart - Address to which the symbol table has to be copied during
* shrinking. If NULL, it is not moved.
*/
static void
addsymtab(const char *name, void *symstart, size_t symsize,
void *strstart, size_t strsize, struct ksyms_symtab *tab,
void *newstart)
{
Elf_Sym *sym, *nsym;
int i, j, n;
char *str;
tab->sd_symstart = symstart;
tab->sd_symsize = symsize;
tab->sd_strstart = strstart;
tab->sd_strsize = strsize;
tab->sd_name = name;
tab->sd_minsym = NULL;
tab->sd_maxsym = NULL;
tab->sd_usroffset = 0;
tab->sd_gone = false;
tab->sd_malloc = false; /* XXXLKM */
#ifdef KSYMS_DEBUG
printf("newstart %p sym %p ksyms_symsz %d str %p strsz %d send %p\n",
newstart, symstart, symsize, strstart, strsize,
tab->sd_strstart + tab->sd_strsize);
#endif
/* Pack symbol table by removing all file name references. */
sym = tab->sd_symstart;
nsym = (Elf_Sym *)newstart;
str = tab->sd_strstart;
for (i = n = 0; i < tab->sd_symsize/sizeof(Elf_Sym); i++) {
/*
* Remove useless symbols.
* Should actually remove all typeless symbols.
*/
if (sym[i].st_name == 0)
continue; /* Skip nameless entries */
if (sym[i].st_shndx == SHN_UNDEF)
continue; /* Skip external references */
if (ELF_ST_TYPE(sym[i].st_info) == STT_FILE)
continue; /* Skip filenames */
if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE &&
sym[i].st_value == 0 &&
strcmp(str + sym[i].st_name, "*ABS*") == 0)
continue; /* XXX */
if (ELF_ST_TYPE(sym[i].st_info) == STT_NOTYPE &&
strcmp(str + sym[i].st_name, "gcc2_compiled.") == 0)
continue; /* XXX */
/* Save symbol. Set it as an absolute offset */
nsym[n] = sym[i];
nsym[n].st_shndx = SHN_ABS;
j = strlen(nsym[n].st_name + tab->sd_strstart) + 1;
if (j > ksyms_maxlen)
ksyms_maxlen = j;
n++;
}
tab->sd_symstart = nsym;
tab->sd_symsize = n * sizeof(Elf_Sym);
/* ksymsread() is unlocked, so membar. */
membar_producer();
TAILQ_INSERT_TAIL(&ksyms_symtabs, tab, sd_queue);
ksyms_sizes_calc();
ksyms_initted = true;
}
void
ksyms_init_finalize()
{
mutex_init(&ksyms_lock, MUTEX_DEFAULT, IPL_NONE);
}
/*
* Setup the kernel symbol table stuff.
*/
void
ksyms_init(int symsize, void *start, void *end)
{
int i, j;
Elf_Shdr *shdr;
char *symstart = NULL, *strstart = NULL;
size_t strsize = 0;
Elf_Ehdr *ehdr;
#ifdef SYMTAB_SPACE
if (symsize <= 0 &&
strncmp(db_symtab, SYMTAB_FILLER, sizeof(SYMTAB_FILLER))) {
symsize = db_symtabsize;
start = db_symtab;
end = db_symtab + db_symtabsize;
}
#endif
if (symsize <= 0) {
printf("[ Kernel symbol table missing! ]\n");
return;
}
/* Sanity check */
if (ALIGNED_POINTER(start, long) == 0) {
printf("[ Kernel symbol table has bad start address %p ]\n",
start);
return;
}
ehdr = (Elf_Ehdr *)start;
/* check if this is a valid ELF header */
/* No reason to verify arch type, the kernel is actually running! */
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
ehdr->e_ident[EI_CLASS] != ELFCLASS ||
ehdr->e_version > 1) {
printf("[ Kernel symbol table invalid! ]\n");
return; /* nothing to do */
}
/* Loaded header will be scratched in addsymtab */
ksyms_hdr_init(start);
/* Find the symbol table and the corresponding string table. */
shdr = (Elf_Shdr *)((uint8_t *)start + ehdr->e_shoff);
for (i = 1; i < ehdr->e_shnum; i++) {
if (shdr[i].sh_type != SHT_SYMTAB)
continue;
if (shdr[i].sh_offset == 0)
continue;
symstart = (uint8_t *)start + shdr[i].sh_offset;
symsize = shdr[i].sh_size;
j = shdr[i].sh_link;
if (shdr[j].sh_offset == 0)
continue; /* Can this happen? */
strstart = (uint8_t *)start + shdr[j].sh_offset;
strsize = shdr[j].sh_size;
break;
}
if (!ksyms_verify(symstart, strstart))
return;
addsymtab("netbsd", symstart, symsize, strstart, strsize,
&kernel_symtab, start);
#ifdef DEBUG
printf("Loaded initial symtab at %p, strtab at %p, # entries %ld\n",
kernel_symtab.sd_symstart, kernel_symtab.sd_strstart,
(long)kernel_symtab.sd_symsize/sizeof(Elf_Sym));
#endif
}
/*
* Setup the kernel symbol table stuff.
* Use this when the address of the symbol and string tables are known;
* otherwise use ksyms_init with an ELF image.
* We need to pass a minimal ELF header which will later be completed by
* ksyms_hdr_init and handed off to userland through /dev/ksyms. We use
* a void *rather than a pointer to avoid exposing the Elf_Ehdr type.
*/
void
ksyms_init_explicit(void *ehdr, void *symstart, size_t symsize,
void *strstart, size_t strsize)
{
if (!ksyms_verify(symstart, strstart))
return;
ksyms_hdr_init(ehdr);
addsymtab("netbsd", symstart, symsize, strstart, strsize,
&kernel_symtab, symstart);
}
/*
* Get the value associated with a symbol.
* "mod" is the module name, or null if any module.
* "sym" is the symbol name.
* "val" is a pointer to the corresponding value, if call succeeded.
* Returns 0 if success or ENOENT if no such entry.
*
* Call with ksyms_lock, unless known that the symbol table can't change.
*/
int
ksyms_getval_unlocked(const char *mod, const char *sym, unsigned long *val,
int type)
{
struct ksyms_symtab *st;
Elf_Sym *es;
if (!ksyms_initted)
return ENOENT;
#ifdef KSYMS_DEBUG
if (ksyms_debug & FOLLOW_CALLS)
printf("ksyms_getval_unlocked: mod %s sym %s valp %p\n",
mod, sym, val);
#endif
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (mod && strcmp(st->sd_name, mod))
continue;
if ((es = findsym(sym, st)) == NULL)
continue;
if (es->st_shndx == SHN_UNDEF)
continue;
/* Skip if bad binding */
if (type == KSYMS_EXTERN &&
ELF_ST_BIND(es->st_info) != STB_GLOBAL)
continue;
if (val)
*val = es->st_value;
return 0;
}
return ENOENT;
}
int
ksyms_getval(const char *mod, const char *sym, unsigned long *val, int type)
{
int rc;
mutex_enter(&ksyms_lock);
rc = ksyms_getval_unlocked(mod, sym, val, type);
mutex_exit(&ksyms_lock);
return rc;
}
/*
* Get "mod" and "symbol" associated with an address.
* Returns 0 if success or ENOENT if no such entry.
*
* Call with ksyms_lock, unless known that the symbol table can't change.
*/
int
ksyms_getname(const char **mod, const char **sym, vaddr_t v, int f)
{
struct ksyms_symtab *st;
Elf_Sym *les, *es = NULL;
vaddr_t laddr = 0;
const char *lmod = NULL;
char *stable = NULL;
int type, i, sz;
if (!ksyms_initted)
return ENOENT;
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (st->sd_minsym != NULL && v < st->sd_minsym->st_value)
continue;
if (st->sd_maxsym != NULL && v > st->sd_maxsym->st_value)
continue;
sz = st->sd_symsize/sizeof(Elf_Sym);
for (i = 0; i < sz; i++) {
les = st->sd_symstart + i;
type = ELF_ST_TYPE(les->st_info);
if ((f & KSYMS_PROC) && (type != STT_FUNC))
continue;
if (type == STT_NOTYPE)
continue;
if (((f & KSYMS_ANY) == 0) &&
(type != STT_FUNC) && (type != STT_OBJECT))
continue;
if ((les->st_value <= v) && (les->st_value > laddr)) {
laddr = les->st_value;
es = les;
lmod = st->sd_name;
stable = st->sd_strstart - st->sd_usroffset;
}
}
}
if (es == NULL)
return ENOENT;
if ((f & KSYMS_EXACT) && (v != es->st_value))
return ENOENT;
if (mod)
*mod = lmod;
if (sym)
*sym = stable + es->st_name;
return 0;
}
/*
* Temporary work structure for dynamic loaded symbol tables.
*
* XXX REMOVE WHEN LKMS GO.
*/
struct syminfo {
size_t cursyms;
size_t curnamep;
size_t maxsyms;
size_t maxnamep;
Elf_Sym *syms;
char *symnames;
};
/*
* Add a symbol to the temporary save area for symbols.
*
* XXX REMOVE WHEN LKMS GO.
*/
static void
addsym(struct syminfo *info, const Elf_Sym *sym, const char *name,
const char *mod)
{
int len, mlen;
#ifdef KSYMS_DEBUG
if (ksyms_debug & FOLLOW_MORE_CALLS)
printf("addsym: name %s val %lx\n", name, (long)sym->st_value);
#endif
len = strlen(name) + 1;
if (mod)
mlen = 1 + strlen(mod);
else
mlen = 0;
if (info->cursyms == info->maxsyms ||
(len + mlen + info->curnamep) > info->maxnamep) {
printf("addsym: too many symbols, skipping '%s'\n", name);
return;
}
strlcpy(&info->symnames[info->curnamep], name,
info->maxnamep - info->curnamep);
if (mlen) {
info->symnames[info->curnamep + len - 1] = '.';
strlcpy(&info->symnames[info->curnamep + len], mod,
info->maxnamep - (info->curnamep + len));
len += mlen;
}
info->syms[info->cursyms] = *sym;
info->syms[info->cursyms].st_name = info->curnamep;
info->curnamep += len;
if (len > ksyms_maxlen)
ksyms_maxlen = len;
info->cursyms++;
}
/*
* XXX REMOVE WHEN LKMS GO.
*/
static int
specialsym(const char *symname)
{
return !strcmp(symname, "_bss_start") ||
!strcmp(symname, "__bss_start") ||
!strcmp(symname, "_bss_end__") ||
!strcmp(symname, "__bss_end__") ||
!strcmp(symname, "_edata") ||
!strcmp(symname, "_end") ||
!strcmp(symname, "__end") ||
!strcmp(symname, "__end__") ||
!strncmp(symname, "__start_link_set_", 17) ||
!strncmp(symname, "__stop_link_set_", 16);
}
/*
* Adds a symbol table.
* "name" is the module name, "start" and "size" is where the symbol table
* is located, and "type" is in which binary format the symbol table is.
* New memory for keeping the symbol table is allocated in this function.
* Returns 0 if success and EEXIST if the module name is in use.
*
* XXX REMOVE WHEN LKMS GO.
*/
int
ksyms_addsymtab(const char *mod, void *symstart, vsize_t symsize,
char *strstart, vsize_t strsize)
{
Elf_Sym *sym = symstart;
struct ksyms_symtab *st;
unsigned long rval;
int i;
char *name;
struct syminfo info;
#ifdef KSYMS_DEBUG
if (ksyms_debug & FOLLOW_CALLS)
printf("ksyms_addsymtab: mod %s symsize %lx strsize %lx\n",
mod, symsize, strsize);
#endif
mutex_enter(&ksyms_lock);
/* Check if this symtab already loaded */
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (strcmp(mod, st->sd_name) == 0) {
mutex_exit(&ksyms_lock);
return EEXIST;
}
}
/*
* XXX - Only add a symbol if it do not exist already.
* This is because of a flaw in the current LKM implementation,
* these loops will be removed once the in-kernel linker is in place.
*/
memset(&info, 0, sizeof(info));
for (i = 0; i < symsize/sizeof(Elf_Sym); i++) {
char * const symname = strstart + sym[i].st_name;
if (sym[i].st_name == 0)
continue; /* Just ignore */
/* check validity of the symbol */
/* XXX - save local symbols if DDB */
if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
continue;
/* Check if the symbol exists */
if (ksyms_getval_unlocked(NULL, symname, &rval, KSYMS_EXTERN)
== 0) {
/* Check (and complain) about differing values */
if (sym[i].st_value != rval &&
sym[i].st_shndx != SHN_UNDEF) {
if (specialsym(symname)) {
info.maxsyms++;
info.maxnamep += strlen(symname) + 1 +
strlen(mod) + 1;
} else {
printf("%s: symbol '%s' redeclared with"
" different value (%lx != %lx)\n",
mod, symname,
rval, (long)sym[i].st_value);
}
}
} else {
/*
* Count this symbol
*/
info.maxsyms++;
info.maxnamep += strlen(symname) + 1;
}
}
/*
* Now that we know the sizes, malloc the structures.
*/
info.syms = malloc(sizeof(Elf_Sym)*info.maxsyms, M_DEVBUF, M_WAITOK);
info.symnames = malloc(info.maxnamep, M_DEVBUF, M_WAITOK);
/*
* Now that we have the symbols, actually fill in the structures.
*/
for (i = 0; i < symsize/sizeof(Elf_Sym); i++) {
char * const symname = strstart + sym[i].st_name;
if (sym[i].st_name == 0)
continue; /* Just ignore */
/* check validity of the symbol */
/* XXX - save local symbols if DDB */
if (ELF_ST_BIND(sym[i].st_info) != STB_GLOBAL)
continue;
/* Check if the symbol exists */
if (ksyms_getval_unlocked(NULL, symname, &rval, KSYMS_EXTERN)
== 0) {
if ((sym[i].st_value != rval) && specialsym(symname)) {
addsym(&info, &sym[i], symname, mod);
}
} else
/* Ok, save this symbol */
addsym(&info, &sym[i], symname, NULL);
}
st = kmem_zalloc(sizeof(*st), KM_SLEEP);
i = strlen(mod) + 1;
name = malloc(i, M_DEVBUF, M_WAITOK);
strlcpy(name, mod, i);
st->sd_name = name;
st->sd_symstart = info.syms;
st->sd_symsize = sizeof(Elf_Sym)*info.maxsyms;
st->sd_strstart = info.symnames;
st->sd_strsize = info.maxnamep;
st->sd_malloc = true;
/* Make them absolute references */
sym = st->sd_symstart;
for (i = 0; i < st->sd_symsize/sizeof(Elf_Sym); i++)
sym[i].st_shndx = SHN_ABS;
/* ksymsread() is unlocked, so membar. */
membar_producer();
TAILQ_INSERT_TAIL(&ksyms_symtabs, st, sd_queue);
ksyms_sizes_calc();
mutex_exit(&ksyms_lock);
return 0;
}
/*
* Remove a symbol table specified by name.
* Returns 0 if success, EBUSY if device open and ENOENT if no such name.
*
* XXX REMOVE WHEN LKMS GO.
*/
int
ksyms_delsymtab(const char *mod)
{
struct ksyms_symtab *st;
mutex_enter(&ksyms_lock);
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (strcmp(mod, st->sd_name) != 0)
continue;
if (ksyms_isopen) {
st->sd_gone = true;
mutex_exit(&ksyms_lock);
return 0;
}
TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue);
ksyms_sizes_calc();
mutex_exit(&ksyms_lock);
KASSERT(st->sd_malloc);
free(st->sd_symstart, M_DEVBUF);
free(st->sd_strstart, M_DEVBUF);
/* XXXUNCONST LINTED - const castaway */
free(__UNCONST(st->sd_name), M_DEVBUF);
kmem_free(st, sizeof(*st));
return 0;
}
mutex_exit(&ksyms_lock);
return ENOENT;
}
/*
* Add a symbol table from a loadable module.
*/
void
ksyms_modload(const char *name, void *symstart, vsize_t symsize,
char *strstart, vsize_t strsize)
{
struct ksyms_symtab *st;
st = kmem_zalloc(sizeof(*st), KM_SLEEP);
mutex_enter(&ksyms_lock);
addsymtab(name, symstart, symsize, strstart, strsize, st, symstart);
mutex_exit(&ksyms_lock);
}
/*
* Remove a symbol table from a loadable module.
*/
void
ksyms_modunload(const char *name)
{
struct ksyms_symtab *st;
mutex_enter(&ksyms_lock);
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (strcmp(name, st->sd_name) != 0)
continue;
KASSERT(!st->sd_malloc); /* XXXLKM */
st->sd_gone = true;
if (!ksyms_isopen) {
TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue);
ksyms_sizes_calc();
kmem_free(st, sizeof(*st));
}
break;
}
mutex_exit(&ksyms_lock);
KASSERT(st != NULL);
}
#ifdef DDB
/*
* Keep sifting stuff here, to avoid export of ksyms internals.
*
* Systems is expected to be quiescent, so no locking done.
*/
int
ksyms_sift(char *mod, char *sym, int mode)
{
struct ksyms_symtab *st;
char *sb;
int i, sz;
if (!ksyms_initted)
return ENOENT;
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if (mod && strcmp(mod, st->sd_name))
continue;
sb = st->sd_strstart - st->sd_usroffset;
sz = st->sd_symsize/sizeof(Elf_Sym);
for (i = 0; i < sz; i++) {
Elf_Sym *les = st->sd_symstart + i;
char c;
if (strstr(sb + les->st_name, sym) == NULL)
continue;
if (mode == 'F') {
switch (ELF_ST_TYPE(les->st_info)) {
case STT_OBJECT:
c = '+';
break;
case STT_FUNC:
c = '*';
break;
case STT_SECTION:
c = '&';
break;
case STT_FILE:
c = '/';
break;
default:
c = ' ';
break;
}
db_printf("%s%c ", sb + les->st_name, c);
} else
db_printf("%s ", sb + les->st_name);
}
}
return ENOENT;
}
#endif /* DDB */
/*
* In case we exposing the symbol table to the userland using the pseudo-
* device /dev/ksyms, it is easier to provide all the tables as one.
* However, it means we have to change all the st_name fields for the
* symbols so they match the ELF image that the userland will read
* through the device.
*
* The actual (correct) value of st_name is preserved through a global
* offset stored in the symbol table structure.
*
* Call with ksyms_lock held.
*/
static void
ksyms_sizes_calc(void)
{
struct ksyms_symtab *st;
int i, delta;
ksyms_symsz = ksyms_strsz = 0;
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
delta = ksyms_strsz - st->sd_usroffset;
if (delta != 0) {
for (i = 0; i < st->sd_symsize/sizeof(Elf_Sym); i++)
st->sd_symstart[i].st_name += delta;
st->sd_usroffset = ksyms_strsz;
}
ksyms_symsz += st->sd_symsize;
ksyms_strsz += st->sd_strsize;
}
}
static void
ksyms_hdr_init(void *hdraddr)
{
/* Copy the loaded elf exec header */
memcpy(&ksyms_hdr.kh_ehdr, hdraddr, sizeof(Elf_Ehdr));
/* Set correct program/section header sizes, offsets and numbers */
ksyms_hdr.kh_ehdr.e_phoff = offsetof(struct ksyms_hdr, kh_phdr[0]);
ksyms_hdr.kh_ehdr.e_phentsize = sizeof(Elf_Phdr);
ksyms_hdr.kh_ehdr.e_phnum = NPRGHDR;
ksyms_hdr.kh_ehdr.e_shoff = offsetof(struct ksyms_hdr, kh_shdr[0]);
ksyms_hdr.kh_ehdr.e_shentsize = sizeof(Elf_Shdr);
ksyms_hdr.kh_ehdr.e_shnum = NSECHDR;
ksyms_hdr.kh_ehdr.e_shstrndx = NSECHDR - 1; /* Last section */
/* Text */
ksyms_hdr.kh_phdr[0].p_type = PT_LOAD;
ksyms_hdr.kh_phdr[0].p_memsz = (unsigned long)-1L;
ksyms_hdr.kh_phdr[0].p_flags = PF_R | PF_X;
/* Data */
ksyms_hdr.kh_phdr[1].p_type = PT_LOAD;
ksyms_hdr.kh_phdr[1].p_memsz = (unsigned long)-1L;
ksyms_hdr.kh_phdr[1].p_flags = PF_R | PF_W | PF_X;
/* First section is null */
/* Second section header; ".symtab" */
ksyms_hdr.kh_shdr[SYMTAB].sh_name = 1; /* Section 3 offset */
ksyms_hdr.kh_shdr[SYMTAB].sh_type = SHT_SYMTAB;
ksyms_hdr.kh_shdr[SYMTAB].sh_offset = sizeof(struct ksyms_hdr);
/* ksyms_hdr.kh_shdr[SYMTAB].sh_size = filled in at open */
ksyms_hdr.kh_shdr[SYMTAB].sh_link = 2; /* Corresponding strtab */
ksyms_hdr.kh_shdr[SYMTAB].sh_addralign = sizeof(long);
ksyms_hdr.kh_shdr[SYMTAB].sh_entsize = sizeof(Elf_Sym);
/* Third section header; ".strtab" */
ksyms_hdr.kh_shdr[STRTAB].sh_name = 9; /* Section 3 offset */
ksyms_hdr.kh_shdr[STRTAB].sh_type = SHT_STRTAB;
/* ksyms_hdr.kh_shdr[STRTAB].sh_offset = filled in at open */
/* ksyms_hdr.kh_shdr[STRTAB].sh_size = filled in at open */
ksyms_hdr.kh_shdr[STRTAB].sh_addralign = sizeof(char);
/* Fourth section, ".shstrtab" */
ksyms_hdr.kh_shdr[SHSTRTAB].sh_name = 17; /* This section name offset */
ksyms_hdr.kh_shdr[SHSTRTAB].sh_type = SHT_STRTAB;
ksyms_hdr.kh_shdr[SHSTRTAB].sh_offset =
offsetof(struct ksyms_hdr, kh_strtab);
ksyms_hdr.kh_shdr[SHSTRTAB].sh_size = SHSTRSIZ;
ksyms_hdr.kh_shdr[SHSTRTAB].sh_addralign = sizeof(char);
/* Set section names */
strlcpy(&ksyms_hdr.kh_strtab[1], ".symtab",
sizeof(ksyms_hdr.kh_strtab) - 1);
strlcpy(&ksyms_hdr.kh_strtab[9], ".strtab",
sizeof(ksyms_hdr.kh_strtab) - 9);
strlcpy(&ksyms_hdr.kh_strtab[17], ".shstrtab",
sizeof(ksyms_hdr.kh_strtab) - 17);
}
static int
ksymsopen(dev_t dev, int oflags, int devtype, struct lwp *l)
{
if (minor(dev) != 0 || !ksyms_initted)
return ENXIO;
/*
* Create a "snapshot" of the kernel symbol table. Setting
* ksyms_isopen will prevent symbol tables from being freed.
*/
mutex_enter(&ksyms_lock);
ksyms_hdr.kh_shdr[SYMTAB].sh_size = ksyms_symsz;
ksyms_hdr.kh_shdr[SYMTAB].sh_info = ksyms_symsz / sizeof(Elf_Sym);
ksyms_hdr.kh_shdr[STRTAB].sh_offset = ksyms_symsz +
ksyms_hdr.kh_shdr[SYMTAB].sh_offset;
ksyms_hdr.kh_shdr[STRTAB].sh_size = ksyms_strsz;
ksyms_isopen = true;
mutex_exit(&ksyms_lock);
return 0;
}
static int
ksymsclose(dev_t dev, int oflags, int devtype, struct lwp *l)
{
struct ksyms_symtab *st, *next;
bool resize;
/* Discard refernces to symbol tables. */
mutex_enter(&ksyms_lock);
ksyms_isopen = false;
resize = false;
for (st = TAILQ_FIRST(&ksyms_symtabs); st != NULL; st = next) {
next = TAILQ_NEXT(st, sd_queue);
if (st->sd_gone) {
TAILQ_REMOVE(&ksyms_symtabs, st, sd_queue);
kmem_free(st, sizeof(*st));
if (st->sd_malloc) { /* XXXLKM */
free(st->sd_symstart, M_DEVBUF);
free(st->sd_strstart, M_DEVBUF);
/* XXXUNCONST LINTED - const castaway */
free(__UNCONST(st->sd_name), M_DEVBUF);
}
resize = true;
}
}
if (resize)
ksyms_sizes_calc();
mutex_exit(&ksyms_lock);
return 0;
}
static int
ksymsread(dev_t dev, struct uio *uio, int ioflag)
{
struct ksyms_symtab *st;
size_t filepos, inpos, off;
int error;
/*
* First: Copy out the ELF header. XXX Lose if ksymsopen()
* occurs during read of the header.
*/
off = uio->uio_offset;
if (off < sizeof(struct ksyms_hdr)) {
error = uiomove((char *)&ksyms_hdr + off,
sizeof(struct ksyms_hdr) - off, uio);
if (error != 0)
return error;
}
/*
* Copy out the symbol table.
*/
filepos = sizeof(struct ksyms_hdr);
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (uio->uio_resid == 0)
return 0;
if (uio->uio_offset <= st->sd_symsize + filepos) {
inpos = uio->uio_offset - filepos;
error = uiomove((char *)st->sd_symstart + inpos,
st->sd_symsize - inpos, uio);
if (error != 0)
return error;
}
filepos += st->sd_symsize;
}
/*
* Copy out the string table
*/
KASSERT(filepos == sizeof(struct ksyms_hdr) +
ksyms_hdr.kh_shdr[SYMTAB].sh_size);
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (uio->uio_resid == 0)
return 0;
if (uio->uio_offset <= st->sd_strsize + filepos) {
inpos = uio->uio_offset - filepos;
error = uiomove((char *)st->sd_strstart + inpos,
st->sd_strsize - inpos, uio);
if (error != 0)
return error;
}
filepos += st->sd_strsize;
}
return 0;
}
static int
ksymswrite(dev_t dev, struct uio *uio, int ioflag)
{
return EROFS;
}
static int
ksymsioctl(dev_t dev, u_long cmd, void *data, int fflag, struct lwp *l)
{
struct ksyms_gsymbol *kg = (struct ksyms_gsymbol *)data;
struct ksyms_symtab *st;
Elf_Sym *sym = NULL, copy;
unsigned long val;
int error = 0;
char *str = NULL;
int len;
/* Read ksyms_maxlen only once while not holding the lock. */
len = ksyms_maxlen;
if (cmd == KIOCGVALUE || cmd == KIOCGSYMBOL) {
str = kmem_alloc(len, KM_SLEEP);
if ((error = copyinstr(kg->kg_name, str, len, NULL)) != 0) {
kmem_free(str, len);
return error;
}
}
switch (cmd) {
case KIOCGVALUE:
/*
* Use the in-kernel symbol lookup code for fast
* retreival of a value.
*/
error = ksyms_getval(NULL, str, &val, KSYMS_EXTERN);
if (error == 0)
error = copyout(&val, kg->kg_value, sizeof(long));
kmem_free(str, len);
break;
case KIOCGSYMBOL:
/*
* Use the in-kernel symbol lookup code for fast
* retreival of a symbol.
*/
mutex_enter(&ksyms_lock);
TAILQ_FOREACH(st, &ksyms_symtabs, sd_queue) {
if (st->sd_gone)
continue;
if ((sym = findsym(str, st)) == NULL)
continue;
#ifdef notdef
/* Skip if bad binding */
if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL) {
sym = NULL;
continue;
}
#endif
break;
}
if (sym != NULL) {
memcpy(©, sym, sizeof(copy));
mutex_exit(&ksyms_lock);
error = copyout(©, kg->kg_sym, sizeof(Elf_Sym));
} else {
mutex_exit(&ksyms_lock);
error = ENOENT;
}
kmem_free(str, len);
break;
case KIOCGSIZE:
/*
* Get total size of symbol table.
*/
mutex_enter(&ksyms_lock);
*(int *)data = ksyms_strsz + ksyms_symsz +
sizeof(struct ksyms_hdr);
mutex_exit(&ksyms_lock);
break;
default:
error = ENOTTY;
break;
}
return error;
}
const struct cdevsw ksyms_cdevsw = {
ksymsopen, ksymsclose, ksymsread, ksymswrite, ksymsioctl,
nullstop, notty, nopoll, nommap, nullkqfilter, D_OTHER | D_MPSAFE
};