/* Native-dependent code for FreeBSD/i386. Copyright 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "inferior.h" #include "regcache.h" #include "target.h" #include <sys/types.h> #include <sys/ptrace.h> #include <sys/sysctl.h> #include "fbsd-nat.h" #include "i386-tdep.h" #include "i386bsd-nat.h" /* Resume execution of the inferior process. If STEP is nonzero, single-step it. If SIGNAL is nonzero, give it that signal. */ static void i386fbsd_resume (ptid_t ptid, int step, enum target_signal signal) { pid_t pid = ptid_get_pid (ptid); int request = PT_STEP; if (pid == -1) /* Resume all threads. This only gets used in the non-threaded case, where "resume all threads" and "resume inferior_ptid" are the same. */ pid = ptid_get_pid (inferior_ptid); if (!step) { ULONGEST eflags; /* Workaround for a bug in FreeBSD. Make sure that the trace flag is off when doing a continue. There is a code path through the kernel which leaves the flag set when it should have been cleared. If a process has a signal pending (such as SIGALRM) and we do a PT_STEP, the process never really has a chance to run because the kernel needs to notify the debugger that a signal is being sent. Therefore, the process never goes through the kernel's trap() function which would normally clear it. */ regcache_cooked_read_unsigned (current_regcache, I386_EFLAGS_REGNUM, &eflags); if (eflags & 0x0100) regcache_cooked_write_unsigned (current_regcache, I386_EFLAGS_REGNUM, eflags & ~0x0100); request = PT_CONTINUE; } /* An addres of (caddr_t) 1 tells ptrace to continue from where it was. (If GDB wanted it to start some other way, we have already written a new PC value to the child.) */ if (ptrace (request, pid, (caddr_t) 1, target_signal_to_host (signal)) == -1) perror_with_name (("ptrace")); } /* Support for debugging kernel virtual memory images. */ #include <sys/types.h> #include <machine/pcb.h> #include "bsd-kvm.h" static int i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) { /* The following is true for FreeBSD 4.7: The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs. This accounts for all callee-saved registers specified by the psABI and then some. Here %esp contains the stack pointer at the point just after the call to cpu_switch(). From this information we reconstruct the register state as it would look when we just returned from cpu_switch(). */ /* The stack pointer shouldn't be zero. */ if (pcb->pcb_esp == 0) return 0; pcb->pcb_esp += 4; regcache_raw_supply (regcache, I386_EDI_REGNUM, &pcb->pcb_edi); regcache_raw_supply (regcache, I386_ESI_REGNUM, &pcb->pcb_esi); regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp); regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp); regcache_raw_supply (regcache, I386_EBX_REGNUM, &pcb->pcb_ebx); regcache_raw_supply (regcache, I386_EIP_REGNUM, &pcb->pcb_eip); regcache_raw_supply (regcache, I386_GS_REGNUM, &pcb->pcb_gs); return 1; } /* Prevent warning from -Wmissing-prototypes. */ void _initialize_i386fbsd_nat (void); void _initialize_i386fbsd_nat (void) { struct target_ops *t; /* Add some extra features to the common *BSD/i386 target. */ t = i386bsd_target (); t->to_resume = i386fbsd_resume; t->to_pid_to_exec_file = fbsd_pid_to_exec_file; t->to_find_memory_regions = fbsd_find_memory_regions; t->to_make_corefile_notes = fbsd_make_corefile_notes; add_target (t); /* Support debugging kernel virtual memory images. */ bsd_kvm_add_target (i386fbsd_supply_pcb); /* FreeBSD provides a kern.ps_strings sysctl that we can use to locate the sigtramp. That way we can still recognize a sigtramp if its location is changed in a new kernel. Of course this is still based on the assumption that the sigtramp is placed directly under the location where the program arguments and environment can be found. */ #ifdef KERN_PS_STRINGS { int mib[2]; u_long ps_strings; size_t len; mib[0] = CTL_KERN; mib[1] = KERN_PS_STRINGS; len = sizeof (ps_strings); if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0) { i386fbsd_sigtramp_start_addr = ps_strings - 128; i386fbsd_sigtramp_end_addr = ps_strings; } } #endif }