i386-linux.c revision 302408 
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 295931 2016-02-23 20:00:55Z 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 <stdio.h>
43#include <sysdecode.h>
44
45#include "truss.h"
46
47static int
48i386_linux_fetch_args(struct trussinfo *trussinfo, u_int narg)
49{
50	struct reg regs;
51	struct current_syscall *cs;
52	lwpid_t tid;
53
54	tid = trussinfo->curthread->tid;
55	cs = &trussinfo->curthread->cs;
56	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
57		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
58		return (-1);
59	}
60
61	/*
62	 * Linux passes syscall arguments in registers, not
63	 * on the stack.  Fortunately, we've got access to the
64	 * register set.  Note that we don't bother checking the
65	 * number of arguments.	And what does linux do for syscalls
66	 * that have more than five arguments?
67	 */
68	switch (narg) {
69	default:
70		cs->args[5] = regs.r_ebp;	/* Unconfirmed */
71	case 5:
72		cs->args[4] = regs.r_edi;
73	case 4:
74		cs->args[3] = regs.r_esi;
75	case 3:
76		cs->args[2] = regs.r_edx;
77	case 2:
78		cs->args[1] = regs.r_ecx;
79	case 1:
80		cs->args[0] = regs.r_ebx;
81	}
82
83	return (0);
84}
85
86static int
87i386_linux_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
88{
89	struct reg regs;
90	lwpid_t tid;
91
92	tid = trussinfo->curthread->tid;
93	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
94		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
95		return (-1);
96	}
97
98	retval[0] = regs.r_eax;
99	retval[1] = regs.r_edx;
100	*errorp = !!(regs.r_eflags & PSL_C);
101	return (0);
102}
103
104static struct procabi i386_linux = {
105	"Linux ELF",
106	SYSDECODE_ABI_LINUX,
107	i386_linux_fetch_args,
108	i386_linux_fetch_retval
109};
110
111PROCABI(i386_linux);
112