freebsd-skq/usr.bin/truss/amd64-freebsd.c
jhb d833056000 Rework syscall structure lookups.
Avoid always using an O(n^2) loop over known syscall structures with
strcmp() on each system call.  Instead, use a per-ABI cache indexed by
the system call number. The first 1024 system calls (which should cover
all of the normal system calls in currently-supported ABIs) use a flat array
indexed by the system call number to find system call structure.  For other
system calls, a linked list of structures storing an integer to structure
mapping is stored in the ABI.  The linked list isn't very smart, but it
should only be used by buggy applications invoking unknown system calls.

This also fixes handling of unknown system calls which currently trigger
a NULL pointer dereference.

Reviewed by:	kib
MFC after:	2 weeks
2016-12-06 00:39:00 +00:00

133 lines
4.0 KiB
C

/*
* Copyright 1997 Sean Eric Fagan
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Sean Eric Fagan
* 4. Neither the name of the author may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/cdefs.h>
__FBSDID("$FreeBSD$");
/* FreeBSD/amd64-specific system call handling. */
#include <sys/ptrace.h>
#include <sys/syscall.h>
#include <machine/reg.h>
#include <machine/psl.h>
#include <stdbool.h>
#include <stdio.h>
#include <sysdecode.h>
#include "truss.h"
static int
amd64_fetch_args(struct trussinfo *trussinfo, u_int narg)
{
struct ptrace_io_desc iorequest;
struct reg regs;
struct current_syscall *cs;
lwpid_t tid;
u_int i, reg;
tid = trussinfo->curthread->tid;
cs = &trussinfo->curthread->cs;
if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
return (-1);
}
/*
* FreeBSD has two special kinds of system call redirections --
* SYS_syscall, and SYS___syscall. The former is the old syscall()
* routine, basically; the latter is for quad-aligned arguments.
*
* The system call argument count and code from ptrace() already
* account for these, but we need to skip over %rax if it contains
* either of these values.
*/
reg = 0;
switch (regs.r_rax) {
case SYS_syscall:
case SYS___syscall:
reg++;
break;
}
for (i = 0; i < narg && reg < 6; i++, reg++) {
switch (reg) {
case 0: cs->args[i] = regs.r_rdi; break;
case 1: cs->args[i] = regs.r_rsi; break;
case 2: cs->args[i] = regs.r_rdx; break;
case 3: cs->args[i] = regs.r_rcx; break;
case 4: cs->args[i] = regs.r_r8; break;
case 5: cs->args[i] = regs.r_r9; break;
}
}
if (narg > i) {
iorequest.piod_op = PIOD_READ_D;
iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t));
iorequest.piod_addr = &cs->args[i];
iorequest.piod_len = (narg - i) * sizeof(register_t);
ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
if (iorequest.piod_len == 0)
return (-1);
}
return (0);
}
static int
amd64_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
{
struct reg regs;
lwpid_t tid;
tid = trussinfo->curthread->tid;
if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
return (-1);
}
retval[0] = regs.r_rax;
retval[1] = regs.r_rdx;
*errorp = !!(regs.r_rflags & PSL_C);
return (0);
}
static struct procabi amd64_freebsd = {
"FreeBSD ELF64",
SYSDECODE_ABI_FREEBSD,
amd64_fetch_args,
amd64_fetch_retval,
STAILQ_HEAD_INITIALIZER(amd64_freebsd.extra_syscalls),
{ NULL }
};
PROCABI(amd64_freebsd);