libs.c revision 1d9df23bbf4124f12ca7832d6eaaa600e0aa8eda
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 1988 AT&T
* All Rights Reserved
*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Library processing
*/
#include <stdio.h>
#include <string.h>
#include <debug.h>
#include "msg.h"
#include "_libld.h"
/*
* Archive members are typically extracted to resolve an existing undefined
* reference. However, other symbol definitions can cause archive members to
* be processed to determine if the archive member provides a more appropriate
* definition. This routine processes the archive member to determine if the
* member is really required.
*
* i. Tentative symbols may cause the extraction of an archive member.
* If the archive member has a strong defined symbol it will be used.
* If the archive member simply contains another tentative definition,
* or a defined function symbol, then it will not be used.
*
* ii. A symbol reference may define a hidden or protected visibility. The
* reference can only be bound to a definition within a relocatable object
* for this restricted visibility to be satisfied. If the archive member
* provides a definition of the same symbol type, this definition is
* taken. The visibility of the defined symbol is irrelevant, as the most
* restrictive visibility of the reference and the definition will be
* applied to the final symbol.
*/
static int
process_member(Ar_mem *amp, const char *name, Sym_desc *sdp, Ofl_desc *ofl)
{
Sym *syms, *osym = sdp->sd_sym;
Xword symn, cnt;
char *strs;
/*
* Find the first symbol table in the archive member, obtain its
* data buffer and determine the number of global symbols (Note,
* there must be a symbol table present otherwise the archive would
* never have been able to generate its own symbol entry for this
* member).
*/
if (amp->am_syms == 0) {
Elf_Scn *scn = NULL;
Shdr *shdr;
Elf_Data *data;
while (scn = elf_nextscn(amp->am_elf, scn)) {
if ((shdr = elf_getshdr(scn)) == NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETSHDR), amp->am_path);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
if ((shdr->sh_type == SHT_SYMTAB) ||
(shdr->sh_type == SHT_DYNSYM))
break;
}
if ((data = elf_getdata(scn, NULL)) == NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETDATA), amp->am_path);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
syms = (Sym *)data->d_buf;
syms += shdr->sh_info;
symn = shdr->sh_size / shdr->sh_entsize;
symn -= shdr->sh_info;
/*
* Get the data for the associated string table.
*/
if ((scn = elf_getscn(amp->am_elf, (size_t)shdr->sh_link)) ==
NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETSCN), amp->am_path);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
if ((data = elf_getdata(scn, NULL)) == NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETDATA), amp->am_path);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
strs = data->d_buf;
/*
* Initialize the archive member structure in case we have to
* come through here again.
*/
amp->am_syms = syms;
amp->am_strs = strs;
amp->am_symn = symn;
} else {
syms = amp->am_syms;
strs = amp->am_strs;
symn = amp->am_symn;
}
/*
* Loop through the symbol table entries looking for a match for the
* original symbol.
*/
for (cnt = 0; cnt < symn; syms++, cnt++) {
Word shndx;
if ((shndx = syms->st_shndx) == SHN_UNDEF)
continue;
if (osym->st_shndx == SHN_COMMON) {
/*
* Determine whether a tentative symbol definition
* should be overridden.
*/
if ((shndx == SHN_ABS) || (shndx == SHN_COMMON) ||
(ELF_ST_TYPE(syms->st_info) == STT_FUNC))
continue;
/*
* A historic detail requires that a weak definition
* within an archive will not override a strong
* definition (see sym_realtent() resolution and ABI
* symbol binding description - page 4-27).
*/
if ((ELF_ST_BIND(syms->st_info) == STB_WEAK) &&
(ELF_ST_BIND(osym->st_info) != STB_WEAK))
continue;
} else {
/*
* Determine whether a restricted visibility reference
* should be overridden. Don't worry about the
* visibility of the archive member definition, nor
* whether it is weak or global. Any definition is
* better than a binding to an external shared object
* (which is the only event that must presently exist
* for us to be here looking for a better alternative).
*/
if (ELF_ST_TYPE(syms->st_info) !=
ELF_ST_TYPE(osym->st_info))
continue;
}
if (strcmp(strs + syms->st_name, name) == NULL)
return (1);
}
return (0);
}
/*
* Create an archive descriptor. By maintaining a list of archives any
* duplicate occurrences of the same archive specified by the user enable us to
* pick off where the last processing finished.
*/
Ar_desc *
ld_ar_setup(const char *name, Elf *elf, Ofl_desc *ofl)
{
Ar_desc * adp;
size_t number;
Elf_Arsym * start;
/*
* Get the archive symbol table. If this fails, we will
* ignore this file with a warning message.
*/
if ((start = elf_getarsym(elf, &number)) == 0) {
if (elf_errno()) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETARSYM), name);
ofl->ofl_flags |= FLG_OF_FATAL;
} else
eprintf(ofl->ofl_lml, ERR_WARNING,
MSG_INTL(MSG_ELF_ARSYM), name);
return (0);
}
/*
* As this is a new archive reference establish a new descriptor.
*/
if ((adp = libld_malloc(sizeof (Ar_desc))) == 0)
return ((Ar_desc *)S_ERROR);
adp->ad_name = name;
adp->ad_elf = elf;
adp->ad_start = start;
if ((adp->ad_aux = libld_calloc(sizeof (Ar_aux), number)) == 0)
return ((Ar_desc *)S_ERROR);
/*
* Retain any command line options that are applicable to archive
* extraction in case we have to rescan this archive later.
*/
adp->ad_flags = ofl->ofl_flags1 & MSK_OF1_ARCHIVE;
ofl->ofl_arscnt++;
/*
* Add this new descriptor to the list of archives.
*/
if (list_appendc(&ofl->ofl_ars, adp) == 0)
return ((Ar_desc *)S_ERROR);
else
return (adp);
}
/*
* For each archive descriptor, maintain an `Ar_aux' table to parallel the
* archive symbol table (returned from elf_getarsym(3e)). Use this table to
* hold a `Sym_desc' for each symbol (thus reducing the number of
* ld_sym_find()'s), and to hold the `Ar_mem' pointer. The `Ar_mem' element
* can have one of three values indicating the state of the archive member
* associated with the offset for this symbol table entry:
*
* 0 indicates that the member has not been processed.
*
* FLG_ARMEM_PROC
* indicates that the member has been processed.
*
* addr indicates that the member has been investigated to determine if
* it contained a symbol definition we need, but was found not to
* be a candidate for extraction. In this case the members
* structure is maintained for possible later use.
*
* Each time we process an archive member we use its offset value to scan this
* `Ar_aux' list. If the member has been extracted, each entry with the same
* offset has its `Ar_mem' pointer set to FLG_AMMEM_PROC. Thus if we cycle back
* through the archive symbol table we will ignore these symbols as they will
* have already been added to the output image. If a member has been processed
* but found not to contain a symbol we need, each entry with the same offset
* has its `Ar_mem' pointer set to the member structures address.
*/
void
ld_ar_member(Ar_desc * adp, Elf_Arsym * arsym, Ar_aux * aup, Ar_mem * amp)
{
Elf_Arsym * _arsym = arsym;
Ar_aux * _aup = aup;
size_t _off = arsym->as_off;
if (_arsym != adp->ad_start) {
do {
_arsym--;
_aup--;
if (_arsym->as_off != _off)
break;
_aup->au_mem = amp;
} while (_arsym != adp->ad_start);
}
_arsym = arsym;
_aup = aup;
do {
if (_arsym->as_off != _off)
break;
_aup->au_mem = amp;
_arsym++;
_aup++;
} while (_arsym->as_name);
}
/*
* Data structure to indicate whether a symbol is visible for the purpose
* of archive extraction.
*/
static const Boolean
sym_vis[STV_NUM] = {
TRUE, /* STV_DEFAULT */
FALSE, /* STV_INTERNAL */
FALSE, /* STV_HIDDEN */
FALSE, /* STV_PROTECTED */
TRUE, /* STV_EXPORTED */
TRUE, /* STV_SINGLETON */
FALSE /* STV_ELIMINATE */
};
#if STV_NUM != (STV_ELIMINATE + 1)
#error "STV_NUM has grown. Update sym_vis[]."
#endif
/*
* Read the archive symbol table. For each symbol in the table, determine
* whether that symbol satisfies an unresolved reference, tentative reference,
* or a reference that expects hidden or protected visibility. If so, the
* corresponding object from the archive is processed. The archive symbol
* table is searched until we go through a complete pass without satisfying any
* unresolved symbols
*/
uintptr_t
ld_process_archive(const char *name, int fd, Ar_desc *adp, Ofl_desc *ofl)
{
Elf_Arsym * arsym;
Elf_Arhdr * arhdr;
Elf * arelf;
Ar_aux * aup;
Sym_desc * sdp;
char *arname, *arpath;
Xword ndx;
int found, again;
int allexrt = (ofl->ofl_flags1 & FLG_OF1_ALLEXRT) != 0;
uintptr_t err;
Rej_desc rej = { 0 };
/*
* If a fatal error condition has been set there's really no point in
* processing the archive further. Having got to this point we have at
* least established that the archive exists (thus verifying that the
* command line options that got us to this archive are correct). Very
* large archives can take a significant time to process, therefore
* continuing on from here may significantly delay the fatal error
* message the user is already set to receive.
*/
if (ofl->ofl_flags & FLG_OF_FATAL)
return (1);
/*
* If this archive was processed with -z allextract, then all members
* have already been extracted.
*/
if (adp->ad_elf == (Elf *)NULL)
return (1);
/*
* Loop through archive symbol table until we make a complete pass
* without satisfying an unresolved reference. For each archive
* symbol, see if there is a symbol with the same name in ld's
* symbol table. If so, and if that symbol is still unresolved or
* tentative, process the corresponding archive member.
*/
found = again = 0;
do {
DBG_CALL(Dbg_file_ar(ofl->ofl_lml, name, again));
DBG_CALL(Dbg_syms_ar_title(ofl->ofl_lml, name, again));
ndx = again = 0;
for (arsym = adp->ad_start, aup = adp->ad_aux; arsym->as_name;
++arsym, ++aup, ndx++) {
Rej_desc _rej = { 0 };
Ar_mem *amp;
Sym *sym;
Boolean visible = TRUE;
/*
* If the auxiliary members value indicates that this
* member has been processed then this symbol will have
* been added to the output file image already or the
* object was rejected in which case we don't want to
* process it again.
*/
if (aup->au_mem == FLG_ARMEM_PROC)
continue;
/*
* If the auxiliary symbol element is non-zero lookup
* the symbol from the internal symbol table.
* (But you skip this if allextract is specified.)
*/
if ((allexrt == 0) && ((sdp = aup->au_syms) == 0)) {
if ((sdp = ld_sym_find(arsym->as_name,
/* LINTED */
(Word)arsym->as_hash, 0, ofl)) == 0) {
DBG_CALL(Dbg_syms_ar_entry(ofl->ofl_lml,
ndx, arsym));
continue;
}
aup->au_syms = sdp;
}
/*
* With '-z allextract', all members will be extracted.
*
* This archive member is a candidate for extraction if
* the internal symbol originates from an explicit file,
* and represents an undefined or tentative symbol.
*
* By default, weak references do not cause archive
* extraction, however the -zweakextract flag overrides
* this default.
*
* If this symbol has already been bound to a versioned
* shared object, but the shared objects version is not
* available, then a definition of this symbol from
* within the archive is a better candidate. Similarly,
* if this symbol has been bound to a shared object, but
* the original reference expected hidden or protected
* visibility, then a definition of this symbol from
* within the archive is a better candidate.
*/
if (allexrt == 0) {
Boolean vers = TRUE;
Ifl_desc *ifl = sdp->sd_file;
sym = sdp->sd_sym;
if (sdp->sd_ref == REF_DYN_NEED) {
uchar_t vis;
if (ifl->ifl_vercnt) {
Word vndx;
Ver_index *vip;
vndx = sdp->sd_aux->sa_dverndx;
vip = &ifl->ifl_verndx[vndx];
if ((vip->vi_flags &
FLG_VER_AVAIL) == 0)
vers = FALSE;
}
vis = ELF_ST_VISIBILITY(sym->st_other);
visible = sym_vis[vis];
}
if (((ifl->ifl_flags & FLG_IF_NEEDED) == 0) ||
(visible && vers &&
(sym->st_shndx != SHN_UNDEF) &&
(sym->st_shndx != SHN_COMMON)) ||
((ELF_ST_BIND(sym->st_info) == STB_WEAK) &&
(!(ofl->ofl_flags1 & FLG_OF1_WEAKEXT)))) {
DBG_CALL(Dbg_syms_ar_entry(ofl->ofl_lml,
ndx, arsym));
continue;
}
}
/*
* Determine if we have already extracted this member,
* and if so reuse the Ar_mem information.
*/
if ((amp = aup->au_mem) != 0) {
arelf = amp->am_elf;
arname = amp->am_name;
arpath = amp->am_path;
} else {
size_t len;
/*
* Set up a new elf descriptor for this member.
*/
if (elf_rand(adp->ad_elf, arsym->as_off) !=
arsym->as_off) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_ARMEM), name,
EC_WORD(arsym->as_off), ndx,
demangle(arsym->as_name));
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
if ((arelf = elf_begin(fd, ELF_C_READ,
adp->ad_elf)) == NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_BEGIN), name);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
/*
* Construct the member filename.
*/
if ((arhdr = elf_getarhdr(arelf)) == NULL) {
eprintf(ofl->ofl_lml, ERR_ELF,
MSG_INTL(MSG_ELF_GETARHDR), name);
ofl->ofl_flags |= FLG_OF_FATAL;
return (0);
}
arname = arhdr->ar_name;
/*
* Construct the members full pathname, using
* the format "%s(%s)".
*/
len = strlen(name) + strlen(arname) + 3;
if ((arpath = libld_malloc(len)) == 0)
return (S_ERROR);
(void) snprintf(arpath, len,
MSG_ORIG(MSG_FMT_ARMEM), name, arname);
/*
* Determine whether the support library wishes
* to process this open. See comments in
* ld_process_open().
*/
ld_sup_open(ofl, (const char **)&arpath,
(const char **)&arname, &fd,
(FLG_IF_EXTRACT | FLG_IF_NEEDED),
&arelf, adp->ad_elf, arsym->as_off,
elf_kind(arelf));
}
/*
* The symbol for which this archive member is being
* processed may provide a better alternative to the
* symbol that is presently known. Two cases are
* covered:
*
* i. The present symbol represents tentative data.
* The archive member may provide a data
* definition symbol.
* ii. The present symbol represents a reference that
* has seen a definition within a shared object
* dependency, but the reference expects to be
* reduced to hidden or protected visibility.
*/
if ((allexrt == 0) &&
((sym->st_shndx == SHN_COMMON) ||
(visible == FALSE))) {
/*
* If we don't already have a member structure
* allocate one.
*/
if (!amp) {
if ((amp = libld_calloc(sizeof (Ar_mem),
1)) == 0)
return (S_ERROR);
amp->am_elf = arelf;
amp->am_name = arname;
amp->am_path = arpath;
}
DBG_CALL(Dbg_syms_ar_checking(ofl->ofl_lml,
ndx, arsym, arname));
if ((err = process_member(amp, arsym->as_name,
sdp, ofl)) == S_ERROR)
return (S_ERROR);
/*
* If it turns out that we don't need this
* member simply initialize all other auxiliary
* entries that match this offset with this
* members address. In this way we can resuse
* this information if we recurse back to this
* symbol.
*/
if (err == 0) {
if (aup->au_mem == 0)
ld_ar_member(adp, arsym,
aup, amp);
continue;
}
}
/*
* Process the archive member. Retain any error for
* return to the caller.
*/
DBG_CALL(Dbg_syms_ar_resolve(ofl->ofl_lml, ndx, arsym,
arname, allexrt));
if ((err = (uintptr_t)ld_process_ifl(arpath, NULL, fd,
arelf, (FLG_IF_EXTRACT | FLG_IF_NEEDED), ofl,
&_rej)) == S_ERROR)
return (S_ERROR);
/*
* If this member is rejected maintain the first
* rejection error for possible later display. Keep the
* member as extracted so that we don't try and process
* it again on a rescan.
*/
if (_rej.rej_type) {
if (rej.rej_type == 0) {
rej.rej_type = _rej.rej_type;
rej.rej_info = _rej.rej_info;
rej.rej_name = (const char *)arpath;
}
ld_ar_member(adp, arsym, aup, FLG_ARMEM_PROC);
continue;
}
/*
* Indicate that the extracted member is in use. This
* enables debugging diags, and indicates that a further
* rescan of all archives may be necessary.
*/
found = 1;
ofl->ofl_flags1 |= FLG_OF1_EXTRACT;
adp->ad_flags |= FLG_ARD_EXTRACT;
/*
* If not under '-z allextract' signal the need to
* rescan this archive.
*/
if (allexrt == 0)
again = 1;
ld_ar_member(adp, arsym, aup, FLG_ARMEM_PROC);
DBG_CALL(Dbg_util_nl(ofl->ofl_lml, DBG_NL_STD));
}
} while (again);
/*
* If no objects have been found in the archive test for any rejections
* and if one had occurred issue a warning - its possible a user has
* pointed at an archive containing the wrong class of elf members.
*/
if ((found == 0) && (rej.rej_type)) {
Conv_reject_desc_buf_t rej_buf;
eprintf(ofl->ofl_lml, ERR_WARNING,
MSG_INTL(reject[rej.rej_type]),
rej.rej_name ? rej.rej_name : MSG_INTL(MSG_STR_UNKNOWN),
conv_reject_desc(&rej, &rej_buf, ld_targ.t_m.m_mach));
}
/*
* If this archive was extracted by -z allextract, the ar_aux table
* and elf descriptor can be freed. Set ad_elf to NULL to mark the
* archive is completely processed.
*/
if (allexrt) {
(void) elf_end(adp->ad_elf);
adp->ad_elf = (Elf *)NULL;
}
return (1);
}