| 1 | /* Native-dependent code for FreeBSD/i386. |
| 2 | Copyright 2001, 2002, 2003 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 19 | Boston, MA 02111-1307, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "inferior.h" |
| 23 | #include "regcache.h" |
| 24 | |
| 25 | #include <sys/types.h> |
| 26 | #include <sys/ptrace.h> |
| 27 | #include <sys/sysctl.h> |
| 28 | |
| 29 | #include "i386-tdep.h" |
| 30 | |
| 31 | /* Prevent warning from -Wmissing-prototypes. */ |
| 32 | void _initialize_i386fbsd_nat (void); |
| 33 | |
| 34 | /* Resume execution of the inferior process. |
| 35 | If STEP is nonzero, single-step it. |
| 36 | If SIGNAL is nonzero, give it that signal. */ |
| 37 | |
| 38 | void |
| 39 | child_resume (ptid_t ptid, int step, enum target_signal signal) |
| 40 | { |
| 41 | pid_t pid = ptid_get_pid (ptid); |
| 42 | int request = PT_STEP; |
| 43 | |
| 44 | if (pid == -1) |
| 45 | /* Resume all threads. This only gets used in the non-threaded |
| 46 | case, where "resume all threads" and "resume inferior_ptid" are |
| 47 | the same. */ |
| 48 | pid = ptid_get_pid (inferior_ptid); |
| 49 | |
| 50 | if (!step) |
| 51 | { |
| 52 | ULONGEST eflags; |
| 53 | |
| 54 | /* Workaround for a bug in FreeBSD. Make sure that the trace |
| 55 | flag is off when doing a continue. There is a code path |
| 56 | through the kernel which leaves the flag set when it should |
| 57 | have been cleared. If a process has a signal pending (such |
| 58 | as SIGALRM) and we do a PT_STEP, the process never really has |
| 59 | a chance to run because the kernel needs to notify the |
| 60 | debugger that a signal is being sent. Therefore, the process |
| 61 | never goes through the kernel's trap() function which would |
| 62 | normally clear it. */ |
| 63 | |
| 64 | regcache_cooked_read_unsigned (current_regcache, I386_EFLAGS_REGNUM, |
| 65 | &eflags); |
| 66 | if (eflags & 0x0100) |
| 67 | regcache_cooked_write_unsigned (current_regcache, I386_EFLAGS_REGNUM, |
| 68 | eflags & ~0x0100); |
| 69 | |
| 70 | request = PT_CONTINUE; |
| 71 | } |
| 72 | |
| 73 | /* An addres of (caddr_t) 1 tells ptrace to continue from where it |
| 74 | was. (If GDB wanted it to start some other way, we have already |
| 75 | written a new PC value to the child.) */ |
| 76 | if (ptrace (request, pid, (caddr_t) 1, |
| 77 | target_signal_to_host (signal)) == -1) |
| 78 | perror_with_name ("ptrace"); |
| 79 | } |
| 80 | \f |
| 81 | void |
| 82 | _initialize_i386fbsd_nat (void) |
| 83 | { |
| 84 | /* FreeBSD provides a kern.ps_strings sysctl that we can use to |
| 85 | locate the sigtramp. That way we can still recognize a sigtramp |
| 86 | if its location is changed in a new kernel. Of course this is |
| 87 | still based on the assumption that the sigtramp is placed |
| 88 | directly under the location where the program arguments and |
| 89 | environment can be found. */ |
| 90 | #ifdef KERN_PS_STRINGS |
| 91 | { |
| 92 | int mib[2]; |
| 93 | int ps_strings; |
| 94 | size_t len; |
| 95 | |
| 96 | mib[0] = CTL_KERN; |
| 97 | mib[1] = KERN_PS_STRINGS; |
| 98 | len = sizeof (ps_strings); |
| 99 | if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0) |
| 100 | { |
| 101 | i386fbsd_sigtramp_start = ps_strings - 128; |
| 102 | i386fbsd_sigtramp_end = ps_strings; |
| 103 | } |
| 104 | } |
| 105 | #endif |
| 106 | } |