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 #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 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 81 82 /* Support for debugging kernel virtual memory images. */ 83 84 #include <sys/types.h> 85 #include <machine/pcb.h> 86 87 #include "bsd-kvm.h" 88 89 static int 90 i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) 91 { 92 /* The following is true for FreeBSD 4.7: 93 94 The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs. 95 This accounts for all callee-saved registers specified by the 96 psABI and then some. Here %esp contains the stack pointer at the 97 point just after the call to cpu_switch(). From this information 98 we reconstruct the register state as it would look when we just 99 returned from cpu_switch(). */ 100 101 /* The stack pointer shouldn't be zero. */ 102 if (pcb->pcb_esp == 0) 103 return 0; 104 105 pcb->pcb_esp += 4; 106 regcache_raw_supply (regcache, I386_EDI_REGNUM, &pcb->pcb_edi); 107 regcache_raw_supply (regcache, I386_ESI_REGNUM, &pcb->pcb_esi); 108 regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp); 109 regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp); 110 regcache_raw_supply (regcache, I386_EBX_REGNUM, &pcb->pcb_ebx); 111 regcache_raw_supply (regcache, I386_EIP_REGNUM, &pcb->pcb_eip); 112 regcache_raw_supply (regcache, I386_GS_REGNUM, &pcb->pcb_gs); 113 114 return 1; 115 } 116 117 118 /* Prevent warning from -Wmissing-prototypes. */ 119 void _initialize_i386fbsd_nat (void); 120 121 void 122 _initialize_i386fbsd_nat (void) 123 { 124 struct target_ops *t; 125 126 /* Add some extra features to the common *BSD/i386 target. */ 127 t = i386bsd_target (); 128 t->to_resume = i386fbsd_resume; 129 t->to_pid_to_exec_file = fbsd_pid_to_exec_file; 130 t->to_find_memory_regions = fbsd_find_memory_regions; 131 t->to_make_corefile_notes = fbsd_make_corefile_notes; 132 add_target (t); 133 134 /* Support debugging kernel virtual memory images. */ 135 bsd_kvm_add_target (i386fbsd_supply_pcb); 136 137 /* FreeBSD provides a kern.ps_strings sysctl that we can use to 138 locate the sigtramp. That way we can still recognize a sigtramp 139 if its location is changed in a new kernel. Of course this is 140 still based on the assumption that the sigtramp is placed 141 directly under the location where the program arguments and 142 environment can be found. */ 143 #ifdef KERN_PS_STRINGS 144 { 145 int mib[2]; 146 int ps_strings; 147 size_t len; 148 149 mib[0] = CTL_KERN; 150 mib[1] = KERN_PS_STRINGS; 151 len = sizeof (ps_strings); 152 if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0) 153 { 154 i386fbsd_sigtramp_start_addr = ps_strings - 128; 155 i386fbsd_sigtramp_end_addr = ps_strings; 156 } 157 } 158 #endif 159 } 160