* bsd-kvm.c, bsd-kvm.h: New files.

* i386fbsd-nat.c: Include <sys/types.h>, <machine/pcb.h> and
"bsd-kvm.h".
(i386fbsd_supply_pcb): New function.
* Makefile.in (ALLDEPFILES): Add bsd-kvm.c.
(i386fbsd-nat.o): Update dependencies.
(bsd_kvm_h): New variable.
(bsd-kvm.o): New dependency.
* config/i386/fbsd.mh (NATDEPFILES): Add bsd-kvm.o.
(LOADLIBES): New variable.

gdb/ChangeLog

@@ -1,5 +1,16 @@
 2004-05-22  Mark Kettenis  <kettenis@gnu.org>
 
+	* bsd-kvm.c, bsd-kvm.h: New files.
+	* i386fbsd-nat.c: Include <sys/types.h>, <machine/pcb.h> and
+	"bsd-kvm.h".
+	(i386fbsd_supply_pcb): New function.
+	* Makefile.in (ALLDEPFILES): Add bsd-kvm.c.
+	(i386fbsd-nat.o): Update dependencies.
+	(bsd_kvm_h): New variable.
+	(bsd-kvm.o): New dependency.
+	* config/i386/fbsd.mh (NATDEPFILES): Add bsd-kvm.o.
+	(LOADLIBES): New variable.
+
 	* regset.c: Tweak comment.
 	(regset_alloc): Remove descr argument.  Use GDBARCH_OBSTACK_ZALLOC
 	macro.

gdb/Makefile.in

@@ -631,6 +631,7 @@ bcache_h = bcache.h
 bfd_target_h = bfd-target.h
 block_h = block.h
 breakpoint_h = breakpoint.h $(frame_h) $(value_h) $(gdb_events_h)
+bsd_kvm_h = bsd-kvm.h
 buildsym_h = buildsym.h
 call_cmds_h = call-cmds.h
 charset_h = charset.h
@@ -1322,6 +1323,7 @@ ALLDEPFILES = \
 	arm-linux-nat.c arm-linux-tdep.c arm-tdep.c \
 	armnbsd-nat.c armnbsd-tdep.c \
 	avr-tdep.c \
+	bsd-kvm.c \
 	coff-solib.c \
 	core-regset.c core-aout.c corelow.c \
 	dcache.c dpx2-nat.c exec.c fork-child.c \
@@ -1613,6 +1615,8 @@ breakpoint.o: breakpoint.c $(defs_h) $(symtab_h) $(frame_h) $(breakpoint_h) \
 	$(objfiles_h) $(source_h) $(linespec_h) $(completer_h) $(gdb_h) \
 	$(ui_out_h) $(cli_script_h) $(gdb_assert_h) $(block_h) \
 	$(gdb_events_h)
+bsd-kvm.o: bsd-kvm.c $(defs_h) $(frame_h) $(regcache_h) $(target_h) \
+	$(gdb_assert_h) $(readline_h) $(bsd_kvm_h)
 buildsym.o: buildsym.c $(defs_h) $(bfd_h) $(gdb_obstack_h) $(symtab_h) \
 	$(symfile_h) $(objfiles_h) $(gdbtypes_h) $(gdb_assert_h) \
 	$(complaints_h) $(gdb_string_h) $(expression_h) $(language_h) \
@@ -1854,7 +1858,7 @@ i386bsd-tdep.o: i386bsd-tdep.c $(defs_h) $(arch_utils_h) $(frame_h) \
 i386-cygwin-tdep.o: i386-cygwin-tdep.c $(defs_h) $(osabi_h) $(gdb_string_h) \
 	$(i386_tdep_h)
 i386fbsd-nat.o: i386fbsd-nat.c $(defs_h) $(inferior_h) $(regcache_h) \
-	$(i386_tdep_h)
+	$(i386_tdep_h) $(bsd_kvm_h)
 i386fbsd-tdep.o: i386fbsd-tdep.c $(defs_h) $(arch_utils_h) $(osabi_h) \
 	$(i386_tdep_h) $(i387_tdep_h) $(solib_svr4_h)
 i386gnu-nat.o: i386gnu-nat.c $(defs_h) $(inferior_h) $(floatformat_h) \

gdb/bsd-kvm.c

@@ -0,0 +1,226 @@
+/* BSD Kernel Data Access Library (libkvm) interface.
+
+   Copyright 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 "frame.h"
+#include "regcache.h"
+#include "target.h"
+
+#include "gdb_assert.h"
+#include <fcntl.h>
+#include <kvm.h>
+#include <nlist.h>
+#include "readline/readline.h"
+#include <sys/param.h>
+#include <sys/user.h>
+
+#include "bsd-kvm.h"
+
+/* Kernel memory interface descriptor.  */
+kvm_t *core_kd;
+
+/* Address of process control block.  */
+struct pcb *bsd_kvm_paddr;
+
+/* Pointer to architecture-specific function that reconstructs the
+   register state from PCB and supplies it to REGCACHE.  */
+int (*bsd_kvm_supply_pcb)(struct regcache *regcache, struct pcb *pcb);
+
+/* Target ops for libkvm interface.  */
+struct target_ops bsd_kvm_ops;
+
+static void
+bsd_kvm_open (char *filename, int from_tty)
+{
+  char errbuf[_POSIX2_LINE_MAX];
+  char *execfile = NULL;
+  kvm_t *temp_kd;
+
+  target_preopen (from_tty);
+
+  if (filename)
+    {
+      char *temp;
+
+      filename = tilde_expand (filename);
+      if (filename[0] != '/')
+	{
+	  temp = concat (current_directory, "/", filename, NULL);
+	  xfree (filename);
+	  filename = temp;
+	}
+    }
+
+  temp_kd = kvm_openfiles (execfile, filename, NULL, O_RDONLY, errbuf);
+  if (temp_kd == NULL)
+    error ("%s", errbuf);
+
+  unpush_target (&bsd_kvm_ops);
+  core_kd = temp_kd;
+  push_target (&bsd_kvm_ops);
+
+  target_fetch_registers (-1);
+
+  flush_cached_frames ();
+  select_frame (get_current_frame ());
+  print_stack_frame (get_selected_frame (), -1, 1);
+}
+
+static void
+bsd_kvm_close (int quitting)
+{
+  if (core_kd)
+    {
+      if (kvm_close (core_kd) == -1)
+	warning ("%s", kvm_geterr(core_kd));
+      core_kd = NULL;
+    }
+}
+
+static int
+bsd_kvm_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
+		    int write, struct mem_attrib *attrib,
+		    struct target_ops *ops)
+{
+  if (write)
+    return kvm_write (core_kd, memaddr, myaddr, len);
+  else
+    return kvm_read (core_kd, memaddr, myaddr, len);
+
+  return -1;
+}
+
+/* Fetch process control block at address PADDR.  */
+
+static int
+bsd_kvm_fetch_pcb (struct pcb *paddr)
+{
+  struct pcb pcb;
+
+  if (kvm_read (core_kd, (unsigned long) paddr, &pcb, sizeof pcb) == -1)
+    error ("%s", kvm_geterr (core_kd));
+
+  gdb_assert (bsd_kvm_supply_pcb);
+  return bsd_kvm_supply_pcb (current_regcache, &pcb);
+}
+
+static void
+bsd_kvm_fetch_registers (int regnum)
+{
+  struct nlist nl[2];
+
+  if (bsd_kvm_paddr)
+    bsd_kvm_fetch_pcb (bsd_kvm_paddr);
+
+  /* On dumping core, BSD kernels store the faulting context (PCB)
+     in the variable "dumppcb".  */
+  memset (nl, 0, sizeof nl);
+  nl[0].n_name = "_dumppcb";
+
+  if (kvm_nlist (core_kd, nl) == -1)
+    error ("%s", kvm_geterr (core_kd));
+
+  if (nl[0].n_value != 0)
+    {
+      /* Found dumppcb. If it contains a valid context, return
+	 immediately.  */
+      if (bsd_kvm_fetch_pcb ((struct pcb *) nl[0].n_value))
+	return;
+    }
+
+  /* Traditional BSD kernels have a process proc0 that should always
+     be present.  The address of proc0's PCB is stored in the variable
+     "proc0paddr".  */
+
+  memset (nl, 0, sizeof nl);
+  nl[0].n_name = "_proc0paddr";
+
+  if (kvm_nlist (core_kd, nl) == -1)
+    error ("%s", kvm_geterr (core_kd));
+
+  if (nl[0].n_value != 0)
+    {
+      struct pcb *paddr;
+
+      /* Found proc0paddr.  */
+      if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
+	error ("%s", kvm_geterr (core_kd));
+
+      bsd_kvm_fetch_pcb (paddr);
+      return;
+    }
+
+#ifdef HAVE_STRUCT_THREAD_TD_PCB
+  /* In FreeBSD kernels for 5.0-RELEASE and later, the PCB no longer
+     lives in `struct proc' but in `struct thread'.  The `struct
+     thread' for the initial thread for proc0 can be found in the
+     variable "thread0".  */
+
+  memset (nl, 0, sizeof nl);
+  nl[0].n_name = "_thread0";
+
+  if (kvm_nlist (core_kd, nl) == -1)
+    error ("%s", kvm_geterr (core_kd));
+
+  if (nl[0].n_value != 0)
+    {
+      struct pcb *paddr;
+
+      /* Found thread0.  */
+      nl[1].n_value += offsetof (struct thread, td_pcb);
+      if (kvm_read (core_kd, nl[1].n_value, &paddr, sizeof paddr) == -1)
+	error ("%s", kvm_geterr (core_kd));
+
+      bsd_kvm_fetch_pcb (paddr);
+      return;
+    }
+#endif
+
+  error ("Cannot find a valid PCB");
+}
+
+
+/* Add the libkvm interface to the list of all possible targets and
+   register CUPPLY_PCB as the architecture-specific process control
+   block interpreter.  */
+
+void
+bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *))
+{
+  gdb_assert (bsd_kvm_supply_pcb == NULL);
+  bsd_kvm_supply_pcb = supply_pcb;
+
+  bsd_kvm_ops.to_shortname = "kvm";
+  bsd_kvm_ops.to_longname = "Kernel memory interface";
+  bsd_kvm_ops.to_doc = "Use a kernel virtual memory image as a target.\n\
+Optionally specify the filename of a core dump.";
+  bsd_kvm_ops.to_open = bsd_kvm_open;
+  bsd_kvm_ops.to_close = bsd_kvm_close;
+  bsd_kvm_ops.to_fetch_registers = bsd_kvm_fetch_registers;
+  bsd_kvm_ops.to_xfer_memory = bsd_kvm_xfer_memory;
+  bsd_kvm_ops.to_stratum = process_stratum;
+  bsd_kvm_ops.to_has_memory = 1;
+  bsd_kvm_ops.to_has_stack = 1;
+  bsd_kvm_ops.to_has_registers = 1;
+  bsd_kvm_ops.to_magic = OPS_MAGIC;
+
+  add_target (&bsd_kvm_ops);
+}

gdb/bsd-kvm.h

@@ -0,0 +1,35 @@
+/* BSD Kernel Data Access Library (libkvm) interface.
+
+   Copyright 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.  */
+
+#ifndef BSD_KVM_H
+#define BSD_KVM_H
+
+struct pcb;
+struct regcache;
+
+/* Add the libkvm interface to the list of all possible targets and
+   register CUPPLY_PCB as the architecture-specific process control
+   block interpreter.  */
+
+extern void
+  bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *));
+
+#endif /* bsd-kvm.h */

gdb/config/i386/fbsd.mh

@@ -1,5 +1,8 @@
 # Host: FreeBSD/i386
 NATDEPFILES= fork-child.o infptrace.o inftarg.o \
-	i386-nat.o i386bsd-nat.o i386fbsd-nat.o gcore.o fbsd-proc.o
+	i386-nat.o i386bsd-nat.o i386fbsd-nat.o \
+	gcore.o fbsd-proc.o bsd-kvm.o
 NAT_FILE= nm-fbsd.h
 XM_FILE= xm-i386.h
+
+LOADLIBES= -lkvm

gdb/i386fbsd-nat.c

@@ -29,9 +29,6 @@
 
 #include "i386-tdep.h"
 
-/* Prevent warning from -Wmissing-prototypes.  */
-void _initialize_i386fbsd_nat (void);
-
 /* Resume execution of the inferior process.
    If STEP is nonzero, single-step it.
    If SIGNAL is nonzero, give it that signal.  */
@@ -79,6 +76,46 @@ child_resume (ptid_t ptid, int step, enum target_signal signal)
     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)
 {
@@ -104,4 +141,7 @@ _initialize_i386fbsd_nat (void)
       }
   }
 #endif
+
+  /* Support debugging kernel virtual memory images.  */
+  bsd_kvm_add_target (i386fbsd_supply_pcb);
 }