OpenBSD-4.6/lib/libc/gen/nlist.c
/* $OpenBSD: nlist.c,v 1.53 2008/06/04 21:12:50 deraadt Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/types.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <a.out.h> /* pulls in nlist.h */
#ifdef _NLIST_DO_ELF
#include <elf_abi.h>
#endif
#ifdef _NLIST_DO_ECOFF
#include <sys/exec_ecoff.h>
#endif
int __fdnlist(int, struct nlist *);
int __aout_fdnlist(int, struct nlist *);
int __ecoff_fdnlist(int, struct nlist *);
int __elf_fdnlist(int, struct nlist *);
#ifdef _NLIST_DO_ELF
int __elf_is_okay__(Elf_Ehdr *ehdr);
#endif
#define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0)
#ifdef _NLIST_DO_AOUT
int
__aout_fdnlist(int fd, struct nlist *list)
{
struct nlist *p, *s;
char *strtab;
off_t symoff, stroff;
u_long symsize;
int nent, cc;
int strsize, usemalloc = 0;
struct nlist nbuf[1024];
struct exec exec;
if (pread(fd, &exec, sizeof(exec), (off_t)0) != sizeof(exec) ||
N_BADMAG(exec) || exec.a_syms == NULL)
return (-1);
stroff = N_STROFF(exec);
symoff = N_SYMOFF(exec);
symsize = exec.a_syms;
/* Read in the size of the string table. */
if (pread(fd, (void *)&strsize, sizeof(strsize), stroff) !=
sizeof(strsize))
return (-1);
else
stroff += sizeof(strsize);
/*
* Read in the string table. We try mmap, but that will fail
* for /dev/ksyms so fall back on malloc. Since OpenBSD's malloc(3)
* returns memory to the system on free this does not cause bloat.
*/
strsize -= sizeof(strsize);
strtab = mmap(NULL, (size_t)strsize, PROT_READ, MAP_SHARED|MAP_FILE,
fd, stroff);
if (strtab == MAP_FAILED) {
usemalloc = 1;
if ((strtab = (char *)malloc(strsize)) == NULL)
return (-1);
errno = EIO;
if (pread(fd, strtab, strsize, stroff) != strsize) {
nent = -1;
goto aout_done;
}
}
/*
* clean out any left-over information for all valid entries.
* Type and value defined to be 0 if not found; historical
* versions cleared other and desc as well. Also figure out
* the largest string length so don't read any more of the
* string table than we have to.
*
* XXX clearing anything other than n_type and n_value violates
* the semantics given in the man page.
*/
nent = 0;
for (p = list; !ISLAST(p); ++p) {
p->n_type = 0;
p->n_other = 0;
p->n_desc = 0;
p->n_value = 0;
++nent;
}
while (symsize > 0) {
cc = MIN(symsize, sizeof(nbuf));
if (pread(fd, nbuf, cc, symoff) != cc)
break;
symsize -= cc;
symoff += cc;
for (s = nbuf; cc > 0; ++s, cc -= sizeof(*s)) {
char *sname = strtab + s->n_un.n_strx - sizeof(int);
if (s->n_un.n_strx == 0 || (s->n_type & N_STAB) != 0)
continue;
for (p = list; !ISLAST(p); p++) {
char *pname = p->n_un.n_name;
if (*sname != '_' && *pname == '_')
pname++;
if (!strcmp(sname, pname)) {
p->n_value = s->n_value;
p->n_type = s->n_type;
p->n_desc = s->n_desc;
p->n_other = s->n_other;
if (--nent <= 0)
break;
}
}
}
}
aout_done:
if (usemalloc)
free(strtab);
else
munmap(strtab, strsize);
return (nent);
}
#endif /* _NLIST_DO_AOUT */
#ifdef _NLIST_DO_ECOFF
#define check(off, size) ((off < 0) || (off + size > mappedsize))
#define BAD do { rv = -1; goto out; } while (0)
#define BADUNMAP do { rv = -1; goto unmap; } while (0)
int
__ecoff_fdnlist(int fd, struct nlist *list)
{
struct nlist *p;
struct ecoff_exechdr *exechdrp;
struct ecoff_symhdr *symhdrp;
struct ecoff_extsym *esyms;
struct stat st;
char *mappedfile;
size_t mappedsize;
u_long symhdroff, extstroff;
u_int symhdrsize;
int rv, nent;
long i, nesyms;
rv = -3;
if (fstat(fd, &st) < 0)
BAD;
if (st.st_size > SIZE_T_MAX) {
errno = EFBIG;
BAD;
}
mappedsize = st.st_size;
mappedfile = mmap(NULL, mappedsize, PROT_READ, MAP_SHARED|MAP_FILE,
fd, 0);
if (mappedfile == MAP_FAILED)
BAD;
if (check(0, sizeof *exechdrp))
BADUNMAP;
exechdrp = (struct ecoff_exechdr *)&mappedfile[0];
if (ECOFF_BADMAG(exechdrp))
BADUNMAP;
symhdroff = exechdrp->f.f_symptr;
symhdrsize = exechdrp->f.f_nsyms;
if (check(symhdroff, sizeof *symhdrp) ||
sizeof *symhdrp != symhdrsize)
BADUNMAP;
symhdrp = (struct ecoff_symhdr *)&mappedfile[symhdroff];
nesyms = symhdrp->esymMax;
if (check(symhdrp->cbExtOffset, nesyms * sizeof *esyms))
BADUNMAP;
esyms = (struct ecoff_extsym *)&mappedfile[symhdrp->cbExtOffset];
extstroff = symhdrp->cbSsExtOffset;
/*
* clean out any left-over information for all valid entries.
* Type and value defined to be 0 if not found; historical
* versions cleared other and desc as well.
*
* XXX clearing anything other than n_type and n_value violates
* the semantics given in the man page.
*/
nent = 0;
for (p = list; !ISLAST(p); ++p) {
p->n_type = 0;
p->n_other = 0;
p->n_desc = 0;
p->n_value = 0;
++nent;
}
for (i = 0; i < nesyms; i++) {
for (p = list; !ISLAST(p); p++) {
char *nlistname;
char *symtabname;
nlistname = p->n_un.n_name;
if (*nlistname == '_')
nlistname++;
symtabname =
&mappedfile[extstroff + esyms[i].es_strindex];
if (!strcmp(symtabname, nlistname)) {
p->n_value = esyms[i].es_value;
p->n_type = N_EXT; /* XXX */
p->n_desc = 0; /* XXX */
p->n_other = 0; /* XXX */
if (--nent <= 0)
break;
}
}
}
rv = nent;
unmap:
munmap(mappedfile, mappedsize);
out:
return (rv);
}
#endif /* _NLIST_DO_ECOFF */
#ifdef _NLIST_DO_ELF
/*
* __elf_is_okay__ - Determine if ehdr really
* is ELF and valid for the target platform.
*
* WARNING: This is NOT a ELF ABI function and
* as such it's use should be restricted.
*/
int
__elf_is_okay__(Elf_Ehdr *ehdr)
{
int retval = 0;
/*
* We need to check magic, class size, endianess,
* and version before we look at the rest of the
* Elf_Ehdr structure. These few elements are
* represented in a machine independent fashion.
*/
if (IS_ELF(*ehdr) &&
ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS &&
ehdr->e_ident[EI_DATA] == ELF_TARG_DATA &&
ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) {
/* Now check the machine dependant header */
if (ehdr->e_machine == ELF_TARG_MACH &&
ehdr->e_version == ELF_TARG_VER)
retval = 1;
}
return retval;
}
int
__elf_fdnlist(int fd, struct nlist *list)
{
struct nlist *p;
caddr_t strtab;
Elf_Off symoff = 0, symstroff = 0;
Elf_Word symsize = 0, symstrsize = 0;
Elf_Sword nent, cc, i;
Elf_Sym sbuf[1024];
Elf_Sym *s;
Elf_Ehdr ehdr;
Elf_Shdr *shdr = NULL;
Elf_Word shdr_size;
struct stat st;
int usemalloc = 0;
/* Make sure obj is OK */
if (pread(fd, &ehdr, sizeof(Elf_Ehdr), (off_t)0) != sizeof(Elf_Ehdr) ||
!__elf_is_okay__(&ehdr) || fstat(fd, &st) < 0)
return (-1);
/* calculate section header table size */
shdr_size = ehdr.e_shentsize * ehdr.e_shnum;
/* Make sure it's not too big to mmap */
if (shdr_size > SIZE_T_MAX) {
errno = EFBIG;
return (-1);
}
/* mmap section header table */
shdr = (Elf_Shdr *)mmap(NULL, (size_t)shdr_size, PROT_READ,
MAP_SHARED|MAP_FILE, fd, (off_t) ehdr.e_shoff);
if (shdr == MAP_FAILED) {
usemalloc = 1;
if ((shdr = malloc(shdr_size)) == NULL)
return (-1);
if (pread(fd, shdr, shdr_size, (off_t)ehdr.e_shoff) != shdr_size) {
free(shdr);
return (-1);
}
}
/*
* Find the symbol table entry and it's corresponding
* string table entry. Version 1.1 of the ABI states
* that there is only one symbol table but that this
* could change in the future.
*/
for (i = 0; i < ehdr.e_shnum; i++) {
if (shdr[i].sh_type == SHT_SYMTAB) {
symoff = shdr[i].sh_offset;
symsize = shdr[i].sh_size;
symstroff = shdr[shdr[i].sh_link].sh_offset;
symstrsize = shdr[shdr[i].sh_link].sh_size;
break;
}
}
/* Flush the section header table */
if (usemalloc)
free(shdr);
else
munmap((caddr_t)shdr, shdr_size);
/* Check for files too large to mmap. */
/* XXX is this really possible? */
if (symstrsize > SIZE_T_MAX) {
errno = EFBIG;
return (-1);
}
/*
* Map string table into our address space. This gives us
* an easy way to randomly access all the strings, without
* making the memory allocation permanent as with malloc/free
* (i.e., munmap will return it to the system).
*/
if (usemalloc) {
if ((strtab = malloc(symstrsize)) == NULL)
return (-1);
if (pread(fd, strtab, symstrsize, (off_t)symstroff) != symstrsize) {
free(strtab);
return (-1);
}
} else {
strtab = mmap(NULL, (size_t)symstrsize, PROT_READ,
MAP_SHARED|MAP_FILE, fd, (off_t) symstroff);
if (strtab == MAP_FAILED)
return (-1);
}
/*
* clean out any left-over information for all valid entries.
* Type and value defined to be 0 if not found; historical
* versions cleared other and desc as well. Also figure out
* the largest string length so don't read any more of the
* string table than we have to.
*
* XXX clearing anything other than n_type and n_value violates
* the semantics given in the man page.
*/
nent = 0;
for (p = list; !ISLAST(p); ++p) {
p->n_type = 0;
p->n_other = 0;
p->n_desc = 0;
p->n_value = 0;
++nent;
}
/* Don't process any further if object is stripped. */
/* ELFism - dunno if stripped by looking at header */
if (symoff == 0)
goto elf_done;
while (symsize > 0) {
cc = MIN(symsize, sizeof(sbuf));
if (pread(fd, sbuf, cc, (off_t)symoff) != cc)
break;
symsize -= cc;
symoff += cc;
for (s = sbuf; cc > 0; ++s, cc -= sizeof(*s)) {
int soff = s->st_name;
if (soff == 0)
continue;
for (p = list; !ISLAST(p); p++) {
char *sym;
/*
* First we check for the symbol as it was
* provided by the user. If that fails
* and the first char is an '_', skip over
* the '_' and try again.
* XXX - What do we do when the user really
* wants '_foo' and the are symbols
* for both 'foo' and '_foo' in the
* table and 'foo' is first?
*/
sym = p->n_un.n_name;
if (strcmp(&strtab[soff], sym) != 0 &&
(sym[0] != '_' ||
strcmp(&strtab[soff], sym + 1) != 0))
continue;
p->n_value = s->st_value;
/* XXX - type conversion */
/* is pretty rude. */
switch(ELF_ST_TYPE(s->st_info)) {
case STT_NOTYPE:
switch (s->st_shndx) {
case SHN_UNDEF:
p->n_type = N_UNDF;
break;
case SHN_ABS:
p->n_type = N_ABS;
break;
case SHN_COMMON:
p->n_type = N_COMM;
break;
default:
p->n_type = N_COMM | N_EXT;
break;
}
break;
case STT_OBJECT:
p->n_type = N_DATA;
break;
case STT_FUNC:
p->n_type = N_TEXT;
break;
case STT_FILE:
p->n_type = N_FN;
break;
}
if (ELF_ST_BIND(s->st_info) ==
STB_LOCAL)
p->n_type = N_EXT;
p->n_desc = 0;
p->n_other = 0;
if (--nent <= 0)
break;
}
}
}
elf_done:
if (usemalloc)
free(strtab);
else
munmap(strtab, symstrsize);
return (nent);
}
#endif /* _NLIST_DO_ELF */
static struct nlist_handlers {
int (*fn)(int fd, struct nlist *list);
} nlist_fn[] = {
#ifdef _NLIST_DO_AOUT
{ __aout_fdnlist },
#endif
#ifdef _NLIST_DO_ELF
{ __elf_fdnlist },
#endif
#ifdef _NLIST_DO_ECOFF
{ __ecoff_fdnlist },
#endif
};
int
__fdnlist(int fd, struct nlist *list)
{
int n = -1, i;
for (i = 0; i < sizeof(nlist_fn)/sizeof(nlist_fn[0]); i++) {
n = (nlist_fn[i].fn)(fd, list);
if (n != -1)
break;
}
return (n);
}
int
nlist(const char *name, struct nlist *list)
{
int fd, n;
fd = open(name, O_RDONLY, 0);
if (fd < 0)
return (-1);
n = __fdnlist(fd, list);
(void)close(fd);
return (n);
}