| 1 | /* Native-dependent code for FreeBSD/i386. |
| 2 | |
| 3 | Copyright (C) 2001, 2002, 2003, 2004, 2007 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., 51 Franklin Street, Fifth Floor, |
| 20 | Boston, MA 02110-1301, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "inferior.h" |
| 24 | #include "regcache.h" |
| 25 | #include "target.h" |
| 26 | |
| 27 | #include <sys/types.h> |
| 28 | #include <sys/ptrace.h> |
| 29 | #include <sys/sysctl.h> |
| 30 | |
| 31 | #include "fbsd-nat.h" |
| 32 | #include "i386-tdep.h" |
| 33 | #include "i386bsd-nat.h" |
| 34 | |
| 35 | /* Resume execution of the inferior process. If STEP is nonzero, |
| 36 | single-step it. If SIGNAL is nonzero, give it that signal. */ |
| 37 | |
| 38 | static void |
| 39 | i386fbsd_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 | struct regcache *regcache = get_current_regcache (); |
| 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 (regcache, I386_EFLAGS_REGNUM, |
| 66 | &eflags); |
| 67 | if (eflags & 0x0100) |
| 68 | regcache_cooked_write_unsigned (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 | \f |
| 82 | |
| 83 | /* Support for debugging kernel virtual memory images. */ |
| 84 | |
| 85 | #include <sys/types.h> |
| 86 | #include <machine/pcb.h> |
| 87 | |
| 88 | #include "bsd-kvm.h" |
| 89 | |
| 90 | static int |
| 91 | i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) |
| 92 | { |
| 93 | /* The following is true for FreeBSD 4.7: |
| 94 | |
| 95 | The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs. |
| 96 | This accounts for all callee-saved registers specified by the |
| 97 | psABI and then some. Here %esp contains the stack pointer at the |
| 98 | point just after the call to cpu_switch(). From this information |
| 99 | we reconstruct the register state as it would look when we just |
| 100 | returned from cpu_switch(). */ |
| 101 | |
| 102 | /* The stack pointer shouldn't be zero. */ |
| 103 | if (pcb->pcb_esp == 0) |
| 104 | return 0; |
| 105 | |
| 106 | pcb->pcb_esp += 4; |
| 107 | regcache_raw_supply (regcache, I386_EDI_REGNUM, &pcb->pcb_edi); |
| 108 | regcache_raw_supply (regcache, I386_ESI_REGNUM, &pcb->pcb_esi); |
| 109 | regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp); |
| 110 | regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp); |
| 111 | regcache_raw_supply (regcache, I386_EBX_REGNUM, &pcb->pcb_ebx); |
| 112 | regcache_raw_supply (regcache, I386_EIP_REGNUM, &pcb->pcb_eip); |
| 113 | regcache_raw_supply (regcache, I386_GS_REGNUM, &pcb->pcb_gs); |
| 114 | |
| 115 | return 1; |
| 116 | } |
| 117 | \f |
| 118 | |
| 119 | /* Prevent warning from -Wmissing-prototypes. */ |
| 120 | void _initialize_i386fbsd_nat (void); |
| 121 | |
| 122 | void |
| 123 | _initialize_i386fbsd_nat (void) |
| 124 | { |
| 125 | struct target_ops *t; |
| 126 | |
| 127 | /* Add some extra features to the common *BSD/i386 target. */ |
| 128 | t = i386bsd_target (); |
| 129 | t->to_resume = i386fbsd_resume; |
| 130 | t->to_pid_to_exec_file = fbsd_pid_to_exec_file; |
| 131 | t->to_find_memory_regions = fbsd_find_memory_regions; |
| 132 | t->to_make_corefile_notes = fbsd_make_corefile_notes; |
| 133 | add_target (t); |
| 134 | |
| 135 | /* Support debugging kernel virtual memory images. */ |
| 136 | bsd_kvm_add_target (i386fbsd_supply_pcb); |
| 137 | |
| 138 | /* FreeBSD provides a kern.ps_strings sysctl that we can use to |
| 139 | locate the sigtramp. That way we can still recognize a sigtramp |
| 140 | if its location is changed in a new kernel. Of course this is |
| 141 | still based on the assumption that the sigtramp is placed |
| 142 | directly under the location where the program arguments and |
| 143 | environment can be found. */ |
| 144 | #ifdef KERN_PS_STRINGS |
| 145 | { |
| 146 | int mib[2]; |
| 147 | u_long ps_strings; |
| 148 | size_t len; |
| 149 | |
| 150 | mib[0] = CTL_KERN; |
| 151 | mib[1] = KERN_PS_STRINGS; |
| 152 | len = sizeof (ps_strings); |
| 153 | if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0) |
| 154 | { |
| 155 | i386fbsd_sigtramp_start_addr = ps_strings - 128; |
| 156 | i386fbsd_sigtramp_end_addr = ps_strings; |
| 157 | } |
| 158 | } |
| 159 | #endif |
| 160 | } |