i386-linux.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/i386-linux.c 330897 2018-03-14 03:19:51Z eadler $");
36
37/* Linux/i386-specific system call handling. */
38
39#include <sys/ptrace.h>
40
41#include <machine/reg.h>
42#include <machine/psl.h>
43
44#include <stdbool.h>
45#include <stdio.h>
46#include <sysdecode.h>
47
48#include "truss.h"
49
50static int
51i386_linux_fetch_args(struct trussinfo *trussinfo, u_int narg)
52{
53	struct reg regs;
54	struct current_syscall *cs;
55	lwpid_t tid;
56
57	tid = trussinfo->curthread->tid;
58	cs = &trussinfo->curthread->cs;
59	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
60		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
61		return (-1);
62	}
63
64	/*
65	 * Linux passes syscall arguments in registers, not
66	 * on the stack.  Fortunately, we've got access to the
67	 * register set.  Note that we don't bother checking the
68	 * number of arguments.	And what does linux do for syscalls
69	 * that have more than five arguments?
70	 */
71	switch (narg) {
72	default:
73		cs->args[5] = regs.r_ebp;	/* Unconfirmed */
74	case 5:
75		cs->args[4] = regs.r_edi;
76	case 4:
77		cs->args[3] = regs.r_esi;
78	case 3:
79		cs->args[2] = regs.r_edx;
80	case 2:
81		cs->args[1] = regs.r_ecx;
82	case 1:
83		cs->args[0] = regs.r_ebx;
84	}
85
86	return (0);
87}
88
89static int
90i386_linux_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
91{
92	struct reg regs;
93	lwpid_t tid;
94
95	tid = trussinfo->curthread->tid;
96	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
97		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
98		return (-1);
99	}
100
101	retval[0] = regs.r_eax;
102	retval[1] = regs.r_edx;
103	*errorp = !!(regs.r_eflags & PSL_C);
104	return (0);
105}
106
107static struct procabi i386_linux = {
108	"Linux ELF",
109	SYSDECODE_ABI_LINUX,
110	i386_linux_fetch_args,
111	i386_linux_fetch_retval,
112	STAILQ_HEAD_INITIALIZER(i386_linux.extra_syscalls),
113	{ NULL }
114};
115
116PROCABI(i386_linux);
117