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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (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 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <libelf.h>
#include <sys/regset.h>
#include <rtld_db.h>
#include <_rtld_db.h>
#include <msg.h>
#include <stdio.h>
typedef struct {
rd_agent_t *rlid_rap;
psaddr_t rlid_pltaddr;
psaddr_t rlid_gotaddr;
rd_err_e rlid_ret;
} Rli_data;
/*
* Iterator function for rd_loadobj_iter - we are scaning
* each object loaded to try and find the object defining
* the current PLT being traversed - when found we return
* the GOT pointer for that object.
*/
static int
rli_func(const rd_loadobj_t *rl, void *data)
{
Ehdr ehdr;
Phdr phdr;
Rli_data *rli_data;
ulong_t off;
psaddr_t baseaddr;
psaddr_t pltaddr;
uint_t i;
uint_t found_obj = 0;
psaddr_t dynbase = 0;
rd_agent_t *rap;
rd_err_e rc;
rli_data = (Rli_data *)data;
pltaddr = rli_data->rlid_pltaddr;
rap = rli_data->rlid_rap;
if (ps_pread(rap->rd_psp, rl->rl_base, (char *)&ehdr,
sizeof (Ehdr)) != PS_OK) {
rli_data->rlid_ret = RD_ERR;
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_X86_1),
EC_ADDR(rl->rl_base)));
return (0);
}
if (ehdr.e_type == ET_EXEC)
baseaddr = 0;
else
baseaddr = rl->rl_base;
off = rl->rl_base + ehdr.e_phoff;
for (i = 0; i < ehdr.e_phnum; i++) {
if (ps_pread(rap->rd_psp, off, (char *)&phdr,
sizeof (Phdr)) != PS_OK) {
rli_data->rlid_ret = RD_ERR;
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_X86_1),
EC_ADDR(rl->rl_base)));
return (0);
}
if (phdr.p_type == PT_LOAD) {
if ((pltaddr >= (phdr.p_vaddr + baseaddr)) &&
(pltaddr < (phdr.p_vaddr + baseaddr +
phdr.p_memsz))) {
found_obj = 1;
}
} else if (phdr.p_type == PT_DYNAMIC) {
dynbase = phdr.p_vaddr + baseaddr;
}
off += ehdr.e_phentsize;
if (found_obj & dynbase)
break;
}
if (found_obj) {
Dyn dynent;
if (dynbase == 0) {
LOG(ps_plog(MSG_ORIG(MSG_DB_NODYN_X86)));
rli_data->rlid_ret = RD_ERR;
return (0);
}
if ((rc = find_dynamic_ent32(rap, dynbase, DT_PLTGOT,
&dynent)) != RD_OK) {
rli_data->rlid_ret = rc;
return (0);
}
/*
* We've found our gotpntr. Return (0) to stop
* the 'iteration'.
*/
rli_data->rlid_gotaddr = dynent.d_un.d_val + baseaddr;
return (0);
}
return (1);
}
/*
* On x86, basically, a PLT entry looks like this:
* 8048738: ff 25 c8 45 05 08 jmp *0x80545c8 < OFFSET_INTO_GOT>
* 804873e: 68 20 00 00 00 pushl $0x20
* 8048743: e9 70 ff ff ff jmp 0xffffff70 <80486b8> < &.plt >
*
* The first time around OFFSET_INTO_GOT contains address of pushl; this forces
* first time resolution to go thru PLT's first entry (which is a call)
* The nth time around, the OFFSET_INTO_GOT actually contains the resolved
* address of the symbol(name), so the jmp is direct [VT]
* The only complication is when going from a .so to an executable or to
* another .so, we must resolve where the GOT table is for the given
* object.
*/
/* ARGSUSED 3 */
rd_err_e
plt32_resolution(rd_agent_t *rap, psaddr_t pc, lwpid_t lwpid,
psaddr_t pltbase, rd_plt_info_t *rpi)
{
unsigned addr;
unsigned ebx;
psaddr_t pltoff, pltaddr;
if (rtld_db_version >= RD_VERSION3) {
rpi->pi_flags = 0;
rpi->pi_baddr = 0;
}
pltoff = pc - pltbase;
pltaddr = pltbase +
((pltoff / M_PLT_ENTSIZE) * M_PLT_ENTSIZE);
/*
* This is the target of the jmp instruction
*/
if (ps_pread(rap->rd_psp, pltaddr + 2, (char *)&addr,
sizeof (unsigned)) != PS_OK) {
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(pltaddr + 2)));
return (RD_ERR);
}
/*
* Is this branch %ebx relative
*/
if (ps_pread(rap->rd_psp, pltaddr + 1, (char *)&ebx,
sizeof (unsigned)) != PS_OK) {
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(pltaddr + 1)));
return (RD_ERR);
}
/*
* If this .plt call is made via a GOT table (pic code), then
* in order to resolve the PLT we must determine where the
* GOT table is for the object making the call.
*
* We do this by using the rd_loadobj_iter() logic to scan
* all of the objects currently loaded into memory, when we
* find one which contains the .PLT table in question - we
* find the GOT address for that object.
*/
if ((ebx & 0xff) == 0xa3) {
rd_err_e rderr;
Rli_data rli_data;
rli_data.rlid_ret = RD_OK;
rli_data.rlid_pltaddr = pltaddr;
rli_data.rlid_rap = rap;
rli_data.rlid_gotaddr = 0;
if ((rderr = _rd_loadobj_iter32(rap, rli_func, &rli_data))
!= RD_OK) {
return (rderr);
}
if (rli_data.rlid_ret != RD_OK) {
return (rli_data.rlid_ret);
}
if (rli_data.rlid_gotaddr == 0) {
LOG(ps_plog(MSG_ORIG(MSG_DB_NOGOT_X86)));
return (RD_ERR);
}
addr += rli_data.rlid_gotaddr;
}
/*
* Find out what's pointed to by @OFFSET_INTO_GOT
*/
if (ps_pread(rap->rd_psp, addr, (char *)&addr,
sizeof (unsigned)) != PS_OK) {
LOG(ps_plog(MSG_ORIG(MSG_DB_READFAIL_2), EC_ADDR(addr)));
return (RD_ERR);
}
if (addr == (pltaddr + 6)) {
rd_err_e rerr;
/*
* If GOT[ind] points to PLT+6 then this is the first
* time through this PLT.
*/
if ((rerr = rd_binder_exit_addr(rap, MSG_ORIG(MSG_SYM_RTBIND),
&(rpi->pi_target))) != RD_OK) {
return (rerr);
}
rpi->pi_skip_method = RD_RESOLVE_TARGET_STEP;
rpi->pi_nstep = 1;
} else {
/*
* This is the n'th time through and GOT[ind] points
* to the final destination.
*/
rpi->pi_skip_method = RD_RESOLVE_STEP;
rpi->pi_nstep = 1;
rpi->pi_target = 0;
if (rtld_db_version >= RD_VERSION3) {
rpi->pi_flags |= RD_FLG_PI_PLTBOUND;
rpi->pi_baddr = addr;
}
}
return (RD_OK);
}
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