1/* Native-dependent code for FreeBSD/i386. 2 3 Copyright 2001, 2002, 2003, 2004 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 59 Temple Place - Suite 330, 20 Boston, MA 02111-1307, USA. */ 21 22#include "defs.h" 23#include "inferior.h" 24#include "regcache.h" 25 26#include <sys/types.h> 27#include <sys/ptrace.h> 28#include <sys/sysctl.h> 29 30#include "i386-tdep.h" 31 32/* Prevent warning from -Wmissing-prototypes. */ 33void _initialize_i386fbsd_nat (void); 34 35/* Resume execution of the inferior process. 36 If STEP is nonzero, single-step it. 37 If SIGNAL is nonzero, give it that signal. */ 38 39void 40child_resume (ptid_t ptid, int step, enum target_signal signal) 41{ 42 pid_t pid = ptid_get_pid (ptid); 43 int request = PT_STEP; 44 45 if (pid == -1) 46 /* Resume all threads. This only gets used in the non-threaded 47 case, where "resume all threads" and "resume inferior_ptid" are 48 the same. */ 49 pid = ptid_get_pid (inferior_ptid); 50 51 if (!step) 52 { 53 ULONGEST eflags; 54 55 /* Workaround for a bug in FreeBSD. Make sure that the trace 56 flag is off when doing a continue. There is a code path 57 through the kernel which leaves the flag set when it should 58 have been cleared. If a process has a signal pending (such 59 as SIGALRM) and we do a PT_STEP, the process never really has 60 a chance to run because the kernel needs to notify the 61 debugger that a signal is being sent. Therefore, the process 62 never goes through the kernel's trap() function which would 63 normally clear it. */ 64 65 regcache_cooked_read_unsigned (current_regcache, I386_EFLAGS_REGNUM, 66 &eflags); 67 if (eflags & 0x0100) 68 regcache_cooked_write_unsigned (current_regcache, I386_EFLAGS_REGNUM, 69 eflags & ~0x0100); 70 71 request = PT_CONTINUE; 72 } 73 74 /* An addres of (caddr_t) 1 tells ptrace to continue from where it 75 was. (If GDB wanted it to start some other way, we have already 76 written a new PC value to the child.) */ 77 if (ptrace (request, pid, (caddr_t) 1, 78 target_signal_to_host (signal)) == -1) 79 perror_with_name ("ptrace"); 80} 81 82void 83_initialize_i386fbsd_nat (void) 84{ 85 /* FreeBSD provides a kern.ps_strings sysctl that we can use to 86 locate the sigtramp. That way we can still recognize a sigtramp 87 if its location is changed in a new kernel. Of course this is 88 still based on the assumption that the sigtramp is placed 89 directly under the location where the program arguments and 90 environment can be found. */ 91#ifdef KERN_PS_STRINGS 92 { 93 int mib[2]; 94 u_long ps_strings; 95 size_t len; 96 97 mib[0] = CTL_KERN; 98 mib[1] = KERN_PS_STRINGS; 99 len = sizeof (ps_strings); 100 if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0) 101 { 102 i386fbsd_sigtramp_start_addr = ps_strings - 128; 103 i386fbsd_sigtramp_end_addr = ps_strings; 104 } 105 } 106#endif 107} 108