1 /* 2 * Copyright (c) 2013 Denys Vlasenko <vda.linux (at) googlemail.com> 3 * Copyright (c) 2013-2015 Dmitry V. Levin <ldv (at) altlinux.org> 4 * All rights reserved. 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. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * PTRACE_GETREGSET was added to the kernel in v2.6.25, 31 * a PTRACE_GETREGS based fallback is provided for old kernels. 32 */ 33 static int 34 getregs_old(pid_t pid) 35 { 36 /* Use old method, with unreliable heuristical detection of 32-bitness. */ 37 long r = ptrace(PTRACE_GETREGS, pid, NULL, &x86_64_regs); 38 if (r) 39 return r; 40 41 if (x86_64_regs.cs == 0x23) { 42 x86_io.iov_len = sizeof(i386_regs); 43 /* 44 * The order is important: i386_regs and x86_64_regs 45 * are overlaid in memory! 46 */ 47 i386_regs.ebx = x86_64_regs.rbx; 48 i386_regs.ecx = x86_64_regs.rcx; 49 i386_regs.edx = x86_64_regs.rdx; 50 i386_regs.esi = x86_64_regs.rsi; 51 i386_regs.edi = x86_64_regs.rdi; 52 i386_regs.ebp = x86_64_regs.rbp; 53 i386_regs.eax = x86_64_regs.rax; 54 /* i386_regs.xds = x86_64_regs.ds; unused by strace */ 55 /* i386_regs.xes = x86_64_regs.es; ditto... */ 56 /* i386_regs.xfs = x86_64_regs.fs; */ 57 /* i386_regs.xgs = x86_64_regs.gs; */ 58 i386_regs.orig_eax = x86_64_regs.orig_rax; 59 i386_regs.eip = x86_64_regs.rip; 60 /* i386_regs.xcs = x86_64_regs.cs; */ 61 /* i386_regs.eflags = x86_64_regs.eflags; */ 62 i386_regs.esp = x86_64_regs.rsp; 63 /* i386_regs.xss = x86_64_regs.ss; */ 64 } else { 65 x86_io.iov_len = sizeof(x86_64_regs); 66 } 67 return 0; 68 } 69
