1/*
2 * Copyright 1997 Sean Eric Fagan
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 *    must display the following acknowledgement:
14 *	This product includes software developed by Sean Eric Fagan
15 * 4. Neither the name of the author may be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/usr.bin/truss/i386-linux.c 312084 2017-01-13 21:30:18Z jhb $");
34
35/* Linux/i386-specific system call handling. */
36
37#include <sys/ptrace.h>
38
39#include <machine/reg.h>
40#include <machine/psl.h>
41
42#include <stdbool.h>
43#include <stdio.h>
44#include <sysdecode.h>
45
46#include "truss.h"
47
48static int
49i386_linux_fetch_args(struct trussinfo *trussinfo, u_int narg)
50{
51	struct reg regs;
52	struct current_syscall *cs;
53	lwpid_t tid;
54
55	tid = trussinfo->curthread->tid;
56	cs = &trussinfo->curthread->cs;
57	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
58		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
59		return (-1);
60	}
61
62	/*
63	 * Linux passes syscall arguments in registers, not
64	 * on the stack.  Fortunately, we've got access to the
65	 * register set.  Note that we don't bother checking the
66	 * number of arguments.	And what does linux do for syscalls
67	 * that have more than five arguments?
68	 */
69	switch (narg) {
70	default:
71		cs->args[5] = regs.r_ebp;	/* Unconfirmed */
72	case 5:
73		cs->args[4] = regs.r_edi;
74	case 4:
75		cs->args[3] = regs.r_esi;
76	case 3:
77		cs->args[2] = regs.r_edx;
78	case 2:
79		cs->args[1] = regs.r_ecx;
80	case 1:
81		cs->args[0] = regs.r_ebx;
82	}
83
84	return (0);
85}
86
87static int
88i386_linux_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
89{
90	struct reg regs;
91	lwpid_t tid;
92
93	tid = trussinfo->curthread->tid;
94	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
95		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
96		return (-1);
97	}
98
99	retval[0] = regs.r_eax;
100	retval[1] = regs.r_edx;
101	*errorp = !!(regs.r_eflags & PSL_C);
102	return (0);
103}
104
105static struct procabi i386_linux = {
106	"Linux ELF",
107	SYSDECODE_ABI_LINUX,
108	i386_linux_fetch_args,
109	i386_linux_fetch_retval,
110	STAILQ_HEAD_INITIALIZER(i386_linux.extra_syscalls),
111	{ NULL }
112};
113
114PROCABI(i386_linux);
115