amd64-freebsd.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright 1997 Sean Eric Fagan
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by Sean Eric Fagan
17 * 4. Neither the name of the author may be used to endorse or promote
18 *    products derived from this software without specific prior written
19 *    permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: stable/11/usr.bin/truss/amd64-freebsd.c 330897 2018-03-14 03:19:51Z eadler $");
36
37/* FreeBSD/amd64-specific system call handling. */
38
39#include <sys/ptrace.h>
40#include <sys/syscall.h>
41
42#include <machine/reg.h>
43#include <machine/psl.h>
44
45#include <stdbool.h>
46#include <stdio.h>
47#include <sysdecode.h>
48
49#include "truss.h"
50
51static int
52amd64_fetch_args(struct trussinfo *trussinfo, u_int narg)
53{
54	struct ptrace_io_desc iorequest;
55	struct reg regs;
56	struct current_syscall *cs;
57	lwpid_t tid;
58	u_int i, reg;
59
60	tid = trussinfo->curthread->tid;
61	cs = &trussinfo->curthread->cs;
62	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
63		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
64		return (-1);
65	}
66
67	/*
68	 * FreeBSD has two special kinds of system call redirections --
69	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
70	 * routine, basically; the latter is for quad-aligned arguments.
71	 *
72	 * The system call argument count and code from ptrace() already
73	 * account for these, but we need to skip over %rax if it contains
74	 * either of these values.
75	 */
76	reg = 0;
77	switch (regs.r_rax) {
78	case SYS_syscall:
79	case SYS___syscall:
80		reg++;
81		break;
82	}
83
84	for (i = 0; i < narg && reg < 6; i++, reg++) {
85		switch (reg) {
86		case 0: cs->args[i] = regs.r_rdi; break;
87		case 1: cs->args[i] = regs.r_rsi; break;
88		case 2: cs->args[i] = regs.r_rdx; break;
89		case 3: cs->args[i] = regs.r_rcx; break;
90		case 4: cs->args[i] = regs.r_r8; break;
91		case 5: cs->args[i] = regs.r_r9; break;
92		}
93	}
94	if (narg > i) {
95		iorequest.piod_op = PIOD_READ_D;
96		iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t));
97		iorequest.piod_addr = &cs->args[i];
98		iorequest.piod_len = (narg - i) * sizeof(register_t);
99		ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
100		if (iorequest.piod_len == 0)
101			return (-1);
102	}
103
104	return (0);
105}
106
107static int
108amd64_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
109{
110	struct reg regs;
111	lwpid_t tid;
112
113	tid = trussinfo->curthread->tid;
114	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
115		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
116		return (-1);
117	}
118
119	retval[0] = regs.r_rax;
120	retval[1] = regs.r_rdx;
121	*errorp = !!(regs.r_rflags & PSL_C);
122	return (0);
123}
124
125static struct procabi amd64_freebsd = {
126	"FreeBSD ELF64",
127	SYSDECODE_ABI_FREEBSD,
128	amd64_fetch_args,
129	amd64_fetch_retval,
130	STAILQ_HEAD_INITIALIZER(amd64_freebsd.extra_syscalls),
131	{ NULL }
132};
133
134PROCABI(amd64_freebsd);
135