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/* $OpenBSD: ksyms.c,v 1.21 2011/06/23 16:02:33 tedu Exp $ */
/*
* Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
* Copyright (c) 2001 Artur Grabowski <art@openbsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED ``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 AUTHORS 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/param.h>
#include <sys/buf.h>
#include <sys/exec.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <sys/conf.h>
#include <uvm/uvm_extern.h>
#ifdef _NLIST_DO_ELF
#include <sys/exec_elf.h>
#endif
#include <machine/cpu.h>
extern char *esym; /* end of symbol table */
#if defined(__sparc64__) || defined(__mips__)
extern char *ssym; /* end of kernel */
#else
extern long end; /* end of kernel */
#endif
static caddr_t ksym_head;
static caddr_t ksym_syms;
static size_t ksym_head_size;
static size_t ksym_syms_size;
void ksymsattach(int);
/*
* We assume __LDPGSZ is a multiple of PAGE_SIZE (it is)
*/
/*ARGSUSED*/
void
ksymsattach(int num)
{
#if defined(__sparc64__) || defined(__mips__)
if (esym <= ssym) {
printf("/dev/ksyms: Symbol table not valid.\n");
return;
}
#else
if (esym <= (char *)&end) {
printf("/dev/ksyms: Symbol table not valid.\n");
return;
}
#endif
#ifdef _NLIST_DO_ELF
do {
#if defined(__sparc64__) || defined(__mips__)
caddr_t symtab = ssym;
#else
caddr_t symtab = (caddr_t)&end;
#endif
Elf_Ehdr *elf;
Elf_Shdr *shdr;
int i;
elf = (Elf_Ehdr *)symtab;
if (memcmp(elf->e_ident, ELFMAG, SELFMAG) != 0 ||
elf->e_ident[EI_CLASS] != ELFCLASS ||
elf->e_machine != ELF_TARG_MACH)
break;
shdr = (Elf_Shdr *)&symtab[elf->e_shoff];
for (i = 0; i < elf->e_shnum; i++) {
if (shdr[i].sh_type == SHT_SYMTAB) {
break;
}
}
/*
* No symbol table found.
*/
if (i == elf->e_shnum)
break;
/*
* No additional header.
*/
ksym_head_size = 0;
ksym_syms = symtab;
ksym_syms_size = (size_t)(esym - symtab);
return;
} while (0);
#endif
#ifdef _NLIST_DO_AOUT
{
/*
* a.out header.
* Fake up a struct exec.
* We only fill in the following non-zero entries:
* a_text - fake text segment (struct exec only)
* a_syms - size of symbol table
*/
caddr_t symtab = (char *)(&end + 1);
struct exec *k1;
ksym_head_size = __LDPGSZ;
ksym_head = malloc(ksym_head_size, M_DEVBUF, M_NOWAIT | M_ZERO);
if (ksym_head == NULL) {
printf("failed to allocate memory for /dev/ksyms\n");
return;
}
k1 = (struct exec *)ksym_head;
N_SETMAGIC(*k1, ZMAGIC, MID_MACHINE, 0);
k1->a_text = __LDPGSZ;
k1->a_syms = end;
ksym_syms = symtab;
ksym_syms_size = (size_t)(esym - symtab);
}
#endif
}
/*ARGSUSED*/
int
ksymsopen(dev_t dev, int flag, int mode, struct proc *p)
{
/* There are no non-zero minor devices */
if (minor(dev) != 0)
return (ENXIO);
/* This device is read-only */
if ((flag & FWRITE))
return (EPERM);
/* ksym_syms must be initialized */
if (ksym_syms == NULL)
return (ENXIO);
return (0);
}
/*ARGSUSED*/
int
ksymsclose(dev_t dev, int flag, int mode, struct proc *p)
{
return (0);
}
/*ARGSUSED*/
int
ksymsread(dev_t dev, struct uio *uio, int flags)
{
int error;
size_t len;
caddr_t v;
size_t off;
while (uio->uio_resid > 0) {
if (uio->uio_offset >= ksym_head_size + ksym_syms_size)
break;
if (uio->uio_offset < ksym_head_size) {
v = ksym_head + uio->uio_offset;
len = ksym_head_size - uio->uio_offset;
} else {
off = uio->uio_offset - ksym_head_size;
v = ksym_syms + off;
len = ksym_syms_size - off;
}
if (len > uio->uio_resid)
len = uio->uio_resid;
if ((error = uiomove(v, len, uio)) != 0)
return (error);
}
return (0);
}
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