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| Current File : //usr/src/cddl/contrib/opensolaris/lib/libdtrace/i386/dt_isadep.c |
/*
* 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 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <libgen.h>
#include <dt_impl.h>
#include <dt_pid.h>
#include <dis_tables.h>
#if !defined(sun)
#define PR_MODEL_ILP32 1
#define PR_MODEL_LP64 2
#include <libproc_compat.h>
#endif
#define DT_POPL_EBP 0x5d
#define DT_RET 0xc3
#define DT_RET16 0xc2
#define DT_LEAVE 0xc9
#define DT_JMP32 0xe9
#define DT_JMP8 0xeb
#define DT_REP 0xf3
#define DT_MOVL_EBP_ESP 0xe58b
#define DT_ISJ32(op16) (((op16) & 0xfff0) == 0x0f80)
#define DT_ISJ8(op8) (((op8) & 0xf0) == 0x70)
#define DT_MODRM_REG(modrm) (((modrm) >> 3) & 0x7)
static int dt_instr_size(uchar_t *, dtrace_hdl_t *, pid_t, uintptr_t, char);
/*ARGSUSED*/
int
dt_pid_create_entry_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
fasttrap_probe_spec_t *ftp, const GElf_Sym *symp)
{
ftp->ftps_type = DTFTP_ENTRY;
ftp->ftps_pc = (uintptr_t)symp->st_value;
ftp->ftps_size = (size_t)symp->st_size;
ftp->ftps_noffs = 1;
ftp->ftps_offs[0] = 0;
if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
strerror(errno));
return (dt_set_errno(dtp, errno));
}
return (1);
}
static int
dt_pid_has_jump_table(struct ps_prochandle *P, dtrace_hdl_t *dtp,
uint8_t *text, fasttrap_probe_spec_t *ftp, const GElf_Sym *symp)
{
ulong_t i;
int size;
#if defined(sun)
pid_t pid = Pstatus(P)->pr_pid;
char dmodel = Pstatus(P)->pr_dmodel;
#else
pid_t pid = proc_getpid(P);
#if __i386__
char dmodel = PR_MODEL_ILP32;
#elif __amd64__
char dmodel = PR_MODEL_LP64;
#endif
#endif
/*
* Take a pass through the function looking for a register-dependant
* jmp instruction. This could be a jump table so we have to be
* ultra conservative.
*/
for (i = 0; i < ftp->ftps_size; i += size) {
size = dt_instr_size(&text[i], dtp, pid, symp->st_value + i,
dmodel);
/*
* Assume the worst if we hit an illegal instruction.
*/
if (size <= 0) {
dt_dprintf("error at %#lx (assuming jump table)\n", i);
return (1);
}
#ifdef notyet
/*
* Register-dependant jmp instructions start with a 0xff byte
* and have the modrm.reg field set to 4. They can have an
* optional REX prefix on the 64-bit ISA.
*/
if ((text[i] == 0xff && DT_MODRM_REG(text[i + 1]) == 4) ||
(dmodel == PR_MODEL_LP64 && (text[i] & 0xf0) == 0x40 &&
text[i + 1] == 0xff && DT_MODRM_REG(text[i + 2]) == 4)) {
dt_dprintf("found a suspected jump table at %s:%lx\n",
ftp->ftps_func, i);
return (1);
}
#endif
}
return (0);
}
/*ARGSUSED*/
int
dt_pid_create_return_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, uint64_t *stret)
{
uint8_t *text;
ulong_t i, end;
int size;
#if defined(sun)
pid_t pid = Pstatus(P)->pr_pid;
char dmodel = Pstatus(P)->pr_dmodel;
#else
pid_t pid = proc_getpid(P);
#if __i386__
char dmodel = PR_MODEL_ILP32;
#elif __amd64__
char dmodel = PR_MODEL_LP64;
#endif
#endif
/*
* We allocate a few extra bytes at the end so we don't have to check
* for overrunning the buffer.
*/
if ((text = calloc(1, symp->st_size + 4)) == NULL) {
dt_dprintf("mr sparkle: malloc() failed\n");
return (DT_PROC_ERR);
}
if (Pread(P, text, symp->st_size, symp->st_value) != symp->st_size) {
dt_dprintf("mr sparkle: Pread() failed\n");
free(text);
return (DT_PROC_ERR);
}
ftp->ftps_type = DTFTP_RETURN;
ftp->ftps_pc = (uintptr_t)symp->st_value;
ftp->ftps_size = (size_t)symp->st_size;
ftp->ftps_noffs = 0;
/*
* If there's a jump table in the function we're only willing to
* instrument these specific (and equivalent) instruction sequences:
* leave
* [rep] ret
* and
* movl %ebp,%esp
* popl %ebp
* [rep] ret
*
* We do this to avoid accidentally interpreting jump table
* offsets as actual instructions.
*/
if (dt_pid_has_jump_table(P, dtp, text, ftp, symp)) {
for (i = 0, end = ftp->ftps_size; i < end; i += size) {
size = dt_instr_size(&text[i], dtp, pid,
symp->st_value + i, dmodel);
/* bail if we hit an invalid opcode */
if (size <= 0)
break;
if (text[i] == DT_LEAVE && text[i + 1] == DT_RET) {
dt_dprintf("leave/ret at %lx\n", i + 1);
ftp->ftps_offs[ftp->ftps_noffs++] = i + 1;
size = 2;
} else if (text[i] == DT_LEAVE &&
text[i + 1] == DT_REP && text[i + 2] == DT_RET) {
dt_dprintf("leave/rep ret at %lx\n", i + 1);
ftp->ftps_offs[ftp->ftps_noffs++] = i + 1;
size = 3;
} else if (*(uint16_t *)&text[i] == DT_MOVL_EBP_ESP &&
text[i + 2] == DT_POPL_EBP &&
text[i + 3] == DT_RET) {
dt_dprintf("movl/popl/ret at %lx\n", i + 3);
ftp->ftps_offs[ftp->ftps_noffs++] = i + 3;
size = 4;
} else if (*(uint16_t *)&text[i] == DT_MOVL_EBP_ESP &&
text[i + 2] == DT_POPL_EBP &&
text[i + 3] == DT_REP &&
text[i + 4] == DT_RET) {
dt_dprintf("movl/popl/rep ret at %lx\n", i + 3);
ftp->ftps_offs[ftp->ftps_noffs++] = i + 3;
size = 5;
}
}
} else {
for (i = 0, end = ftp->ftps_size; i < end; i += size) {
size = dt_instr_size(&text[i], dtp, pid,
symp->st_value + i, dmodel);
/* bail if we hit an invalid opcode */
if (size <= 0)
break;
/* ordinary ret */
if (size == 1 && text[i] == DT_RET)
goto is_ret;
/* two-byte ret */
if (size == 2 && text[i] == DT_REP &&
text[i + 1] == DT_RET)
goto is_ret;
/* ret <imm16> */
if (size == 3 && text[i] == DT_RET16)
goto is_ret;
/* two-byte ret <imm16> */
if (size == 4 && text[i] == DT_REP &&
text[i + 1] == DT_RET16)
goto is_ret;
/* 32-bit displacement jmp outside of the function */
if (size == 5 && text[i] == DT_JMP32 && symp->st_size <=
(uintptr_t)(i + size + *(int32_t *)&text[i + 1]))
goto is_ret;
/* 8-bit displacement jmp outside of the function */
if (size == 2 && text[i] == DT_JMP8 && symp->st_size <=
(uintptr_t)(i + size + *(int8_t *)&text[i + 1]))
goto is_ret;
/* 32-bit disp. conditional jmp outside of the func. */
if (size == 6 && DT_ISJ32(*(uint16_t *)&text[i]) &&
symp->st_size <=
(uintptr_t)(i + size + *(int32_t *)&text[i + 2]))
goto is_ret;
/* 8-bit disp. conditional jmp outside of the func. */
if (size == 2 && DT_ISJ8(text[i]) && symp->st_size <=
(uintptr_t)(i + size + *(int8_t *)&text[i + 1]))
goto is_ret;
continue;
is_ret:
dt_dprintf("return at offset %lx\n", i);
ftp->ftps_offs[ftp->ftps_noffs++] = i;
}
}
free(text);
if (ftp->ftps_noffs > 0) {
if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
strerror(errno));
return (dt_set_errno(dtp, errno));
}
}
return (ftp->ftps_noffs);
}
/*ARGSUSED*/
int
dt_pid_create_offset_probe(struct ps_prochandle *P, dtrace_hdl_t *dtp,
fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, ulong_t off)
{
ftp->ftps_type = DTFTP_OFFSETS;
ftp->ftps_pc = (uintptr_t)symp->st_value;
ftp->ftps_size = (size_t)symp->st_size;
ftp->ftps_noffs = 1;
if (strcmp("-", ftp->ftps_func) == 0) {
ftp->ftps_offs[0] = off;
} else {
uint8_t *text;
ulong_t i;
int size;
#if defined(sun)
pid_t pid = Pstatus(P)->pr_pid;
char dmodel = Pstatus(P)->pr_dmodel;
#else
pid_t pid = proc_getpid(P);
#if __i386__
char dmodel = PR_MODEL_ILP32;
#elif __amd64__
char dmodel = PR_MODEL_LP64;
#endif
#endif
if ((text = malloc(symp->st_size)) == NULL) {
dt_dprintf("mr sparkle: malloc() failed\n");
return (DT_PROC_ERR);
}
if (Pread(P, text, symp->st_size, symp->st_value) !=
symp->st_size) {
dt_dprintf("mr sparkle: Pread() failed\n");
free(text);
return (DT_PROC_ERR);
}
/*
* We can't instrument offsets in functions with jump tables
* as we might interpret a jump table offset as an
* instruction.
*/
if (dt_pid_has_jump_table(P, dtp, text, ftp, symp)) {
free(text);
return (0);
}
for (i = 0; i < symp->st_size; i += size) {
if (i == off) {
ftp->ftps_offs[0] = i;
break;
}
/*
* If we've passed the desired offset without a
* match, then the given offset must not lie on a
* instruction boundary.
*/
if (i > off) {
free(text);
return (DT_PROC_ALIGN);
}
size = dt_instr_size(&text[i], dtp, pid,
symp->st_value + i, dmodel);
/*
* If we hit an invalid instruction, bail as if we
* couldn't find the offset.
*/
if (size <= 0) {
free(text);
return (DT_PROC_ALIGN);
}
}
free(text);
}
if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
strerror(errno));
return (dt_set_errno(dtp, errno));
}
return (ftp->ftps_noffs);
}
/*ARGSUSED*/
int
dt_pid_create_glob_offset_probes(struct ps_prochandle *P, dtrace_hdl_t *dtp,
fasttrap_probe_spec_t *ftp, const GElf_Sym *symp, const char *pattern)
{
uint8_t *text;
int size;
ulong_t i, end = symp->st_size;
#if defined(sun)
pid_t pid = Pstatus(P)->pr_pid;
char dmodel = Pstatus(P)->pr_dmodel;
#else
pid_t pid = proc_getpid(P);
#if __i386__
char dmodel = PR_MODEL_ILP32;
#elif __amd64__
char dmodel = PR_MODEL_LP64;
#endif
#endif
ftp->ftps_type = DTFTP_OFFSETS;
ftp->ftps_pc = (uintptr_t)symp->st_value;
ftp->ftps_size = (size_t)symp->st_size;
ftp->ftps_noffs = 0;
if ((text = malloc(symp->st_size)) == NULL) {
dt_dprintf("mr sparkle: malloc() failed\n");
return (DT_PROC_ERR);
}
if (Pread(P, text, symp->st_size, symp->st_value) != symp->st_size) {
dt_dprintf("mr sparkle: Pread() failed\n");
free(text);
return (DT_PROC_ERR);
}
/*
* We can't instrument offsets in functions with jump tables as
* we might interpret a jump table offset as an instruction.
*/
if (dt_pid_has_jump_table(P, dtp, text, ftp, symp)) {
free(text);
return (0);
}
if (strcmp("*", pattern) == 0) {
for (i = 0; i < end; i += size) {
ftp->ftps_offs[ftp->ftps_noffs++] = i;
size = dt_instr_size(&text[i], dtp, pid,
symp->st_value + i, dmodel);
/* bail if we hit an invalid opcode */
if (size <= 0)
break;
}
} else {
char name[sizeof (i) * 2 + 1];
for (i = 0; i < end; i += size) {
(void) snprintf(name, sizeof (name), "%lx", i);
if (gmatch(name, pattern))
ftp->ftps_offs[ftp->ftps_noffs++] = i;
size = dt_instr_size(&text[i], dtp, pid,
symp->st_value + i, dmodel);
/* bail if we hit an invalid opcode */
if (size <= 0)
break;
}
}
free(text);
if (ftp->ftps_noffs > 0) {
if (ioctl(dtp->dt_ftfd, FASTTRAPIOC_MAKEPROBE, ftp) != 0) {
dt_dprintf("fasttrap probe creation ioctl failed: %s\n",
strerror(errno));
return (dt_set_errno(dtp, errno));
}
}
return (ftp->ftps_noffs);
}
typedef struct dtrace_dis {
uchar_t *instr;
dtrace_hdl_t *dtp;
pid_t pid;
uintptr_t addr;
} dtrace_dis_t;
static int
dt_getbyte(void *data)
{
dtrace_dis_t *dis = data;
int ret = *dis->instr;
if (ret == FASTTRAP_INSTR) {
fasttrap_instr_query_t instr;
instr.ftiq_pid = dis->pid;
instr.ftiq_pc = dis->addr;
/*
* If we hit a byte that looks like the fasttrap provider's
* trap instruction (which doubles as the breakpoint
* instruction for debuggers) we need to query the kernel
* for the real value. This may just be part of an immediate
* value so there's no need to return an error if the
* kernel doesn't know about this address.
*/
if (ioctl(dis->dtp->dt_ftfd, FASTTRAPIOC_GETINSTR, &instr) == 0)
ret = instr.ftiq_instr;
}
dis->addr++;
dis->instr++;
return (ret);
}
static int
dt_instr_size(uchar_t *instr, dtrace_hdl_t *dtp, pid_t pid, uintptr_t addr,
char dmodel)
{
dtrace_dis_t data;
dis86_t x86dis;
uint_t cpu_mode;
data.instr = instr;
data.dtp = dtp;
data.pid = pid;
data.addr = addr;
x86dis.d86_data = &data;
x86dis.d86_get_byte = dt_getbyte;
x86dis.d86_check_func = NULL;
cpu_mode = (dmodel == PR_MODEL_ILP32) ? SIZE32 : SIZE64;
if (dtrace_disx86(&x86dis, cpu_mode) != 0)
return (-1);
/*
* If the instruction was a single-byte breakpoint, there may be
* another debugger attached to this process. The original instruction
* can't be recovered so this must fail.
*/
if (x86dis.d86_len == 1 && instr[0] == FASTTRAP_INSTR)
return (-1);
return (x86dis.d86_len);
}