383 lines
10 KiB
C
383 lines
10 KiB
C
/* BSD Kernel Data Access Library (libkvm) interface.
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Copyright (C) 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "cli/cli-cmds.h"
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#include "command.h"
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#include "frame.h"
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#include "regcache.h"
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#include "target.h"
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#include "value.h"
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#include "gdbcore.h" /* for get_exec_file */
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#include "gdbthread.h"
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#include "gdb_assert.h"
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#include <fcntl.h>
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#include <kvm.h>
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#ifdef HAVE_NLIST_H
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#include <nlist.h>
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#endif
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#include <paths.h>
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#include "readline/readline.h"
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/user.h>
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#include "bsd-kvm.h"
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/* Kernel memory device file. */
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static const char *bsd_kvm_corefile;
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/* Kernel memory interface descriptor. */
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static kvm_t *core_kd;
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/* Address of process control block. */
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static struct pcb *bsd_kvm_paddr;
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/* Pointer to architecture-specific function that reconstructs the
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register state from PCB and supplies it to REGCACHE. */
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static int (*bsd_kvm_supply_pcb)(struct regcache *regcache, struct pcb *pcb);
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/* Target ops for libkvm interface. */
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static struct target_ops bsd_kvm_ops;
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/* This is the ptid we use while we're connected to kvm. The kvm
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target currently doesn't export any view of the running processes,
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so this represents the kernel task. */
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static ptid_t bsd_kvm_ptid;
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static void
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bsd_kvm_open (char *filename, int from_tty)
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{
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char errbuf[_POSIX2_LINE_MAX];
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char *execfile = NULL;
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kvm_t *temp_kd;
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target_preopen (from_tty);
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if (filename)
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{
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char *temp;
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filename = tilde_expand (filename);
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if (filename[0] != '/')
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{
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temp = concat (current_directory, "/", filename, (char *)NULL);
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xfree (filename);
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filename = temp;
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}
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}
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execfile = get_exec_file (0);
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temp_kd = kvm_openfiles (execfile, filename, NULL,
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write_files ? O_RDWR : O_RDONLY, errbuf);
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if (temp_kd == NULL)
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error (("%s"), errbuf);
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bsd_kvm_corefile = filename;
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unpush_target (&bsd_kvm_ops);
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core_kd = temp_kd;
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push_target (&bsd_kvm_ops);
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add_thread_silent (bsd_kvm_ptid);
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inferior_ptid = bsd_kvm_ptid;
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target_fetch_registers (get_current_regcache (), -1);
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reinit_frame_cache ();
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print_stack_frame (get_selected_frame (NULL), -1, 1);
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}
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static void
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bsd_kvm_close (int quitting)
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{
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if (core_kd)
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{
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if (kvm_close (core_kd) == -1)
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warning (("%s"), kvm_geterr(core_kd));
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core_kd = NULL;
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}
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inferior_ptid = null_ptid;
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delete_thread_silent (bsd_kvm_ptid);
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}
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static LONGEST
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bsd_kvm_xfer_memory (CORE_ADDR addr, ULONGEST len,
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gdb_byte *readbuf, const gdb_byte *writebuf)
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{
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ssize_t nbytes = len;
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if (readbuf)
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nbytes = kvm_read (core_kd, addr, readbuf, nbytes);
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if (writebuf && nbytes > 0)
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nbytes = kvm_write (core_kd, addr, writebuf, nbytes);
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return nbytes;
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}
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static LONGEST
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bsd_kvm_xfer_partial (struct target_ops *ops, enum target_object object,
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const char *annex, gdb_byte *readbuf,
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const gdb_byte *writebuf,
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ULONGEST offset, LONGEST len)
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{
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switch (object)
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{
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case TARGET_OBJECT_MEMORY:
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return bsd_kvm_xfer_memory (offset, len, readbuf, writebuf);
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default:
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return -1;
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}
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}
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static void
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bsd_kvm_files_info (struct target_ops *ops)
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{
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if (bsd_kvm_corefile && strcmp (bsd_kvm_corefile, _PATH_MEM) != 0)
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printf_filtered (_("\tUsing the kernel crash dump %s.\n"),
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bsd_kvm_corefile);
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else
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printf_filtered (_("\tUsing the currently running kernel.\n"));
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}
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/* Fetch process control block at address PADDR. */
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static int
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bsd_kvm_fetch_pcb (struct regcache *regcache, struct pcb *paddr)
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{
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struct pcb pcb;
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if (kvm_read (core_kd, (unsigned long) paddr, &pcb, sizeof pcb) == -1)
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error (("%s"), kvm_geterr (core_kd));
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gdb_assert (bsd_kvm_supply_pcb);
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return bsd_kvm_supply_pcb (regcache, &pcb);
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}
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static void
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bsd_kvm_fetch_registers (struct regcache *regcache, int regnum)
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{
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struct nlist nl[2];
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if (bsd_kvm_paddr)
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{
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bsd_kvm_fetch_pcb (regcache, bsd_kvm_paddr);
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return;
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}
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/* On dumping core, BSD kernels store the faulting context (PCB)
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in the variable "dumppcb". */
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memset (nl, 0, sizeof nl);
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nl[0].n_name = "_dumppcb";
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if (kvm_nlist (core_kd, nl) == -1)
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error (("%s"), kvm_geterr (core_kd));
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if (nl[0].n_value != 0)
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{
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/* Found dumppcb. If it contains a valid context, return
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immediately. */
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if (bsd_kvm_fetch_pcb (regcache, (struct pcb *) nl[0].n_value))
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return;
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}
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/* Traditional BSD kernels have a process proc0 that should always
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be present. The address of proc0's PCB is stored in the variable
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"proc0paddr". */
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memset (nl, 0, sizeof nl);
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nl[0].n_name = "_proc0paddr";
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if (kvm_nlist (core_kd, nl) == -1)
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error (("%s"), kvm_geterr (core_kd));
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if (nl[0].n_value != 0)
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{
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struct pcb *paddr;
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/* Found proc0paddr. */
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if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
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error (("%s"), kvm_geterr (core_kd));
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bsd_kvm_fetch_pcb (regcache, paddr);
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return;
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}
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#ifdef HAVE_STRUCT_THREAD_TD_PCB
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/* In FreeBSD kernels for 5.0-RELEASE and later, the PCB no longer
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lives in `struct proc' but in `struct thread'. The `struct
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thread' for the initial thread for proc0 can be found in the
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variable "thread0". */
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memset (nl, 0, sizeof nl);
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nl[0].n_name = "_thread0";
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if (kvm_nlist (core_kd, nl) == -1)
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error (("%s"), kvm_geterr (core_kd));
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if (nl[0].n_value != 0)
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{
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struct pcb *paddr;
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/* Found thread0. */
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nl[0].n_value += offsetof (struct thread, td_pcb);
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if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
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error (("%s"), kvm_geterr (core_kd));
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bsd_kvm_fetch_pcb (regcache, paddr);
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return;
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}
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#endif
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/* i18n: PCB == "Process Control Block" */
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error (_("Cannot find a valid PCB"));
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}
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/* Kernel memory interface commands. */
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struct cmd_list_element *bsd_kvm_cmdlist;
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static void
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bsd_kvm_cmd (char *arg, int fromtty)
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{
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/* ??? Should this become an alias for "target kvm"? */
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}
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#ifndef HAVE_STRUCT_THREAD_TD_PCB
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static void
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bsd_kvm_proc_cmd (char *arg, int fromtty)
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{
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CORE_ADDR addr;
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if (arg == NULL)
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error_no_arg (_("proc address"));
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if (core_kd == NULL)
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error (_("No kernel memory image."));
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addr = parse_and_eval_address (arg);
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#ifdef HAVE_STRUCT_LWP
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addr += offsetof (struct lwp, l_addr);
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#else
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addr += offsetof (struct proc, p_addr);
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#endif
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if (kvm_read (core_kd, addr, &bsd_kvm_paddr, sizeof bsd_kvm_paddr) == -1)
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error (("%s"), kvm_geterr (core_kd));
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target_fetch_registers (get_current_regcache (), -1);
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reinit_frame_cache ();
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print_stack_frame (get_selected_frame (NULL), -1, 1);
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}
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#endif
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static void
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bsd_kvm_pcb_cmd (char *arg, int fromtty)
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{
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if (arg == NULL)
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/* i18n: PCB == "Process Control Block" */
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error_no_arg (_("pcb address"));
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if (core_kd == NULL)
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error (_("No kernel memory image."));
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bsd_kvm_paddr = (struct pcb *)(u_long) parse_and_eval_address (arg);
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target_fetch_registers (get_current_regcache (), -1);
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reinit_frame_cache ();
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print_stack_frame (get_selected_frame (NULL), -1, 1);
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}
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static int
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bsd_kvm_thread_alive (ptid_t ptid)
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{
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return 1;
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}
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static char *
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bsd_kvm_pid_to_str (ptid_t ptid)
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{
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static char buf[64];
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xsnprintf (buf, sizeof buf, "<kvm>");
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return buf;
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}
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/* Add the libkvm interface to the list of all possible targets and
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register CUPPLY_PCB as the architecture-specific process control
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block interpreter. */
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void
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bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *))
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{
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gdb_assert (bsd_kvm_supply_pcb == NULL);
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bsd_kvm_supply_pcb = supply_pcb;
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bsd_kvm_ops.to_shortname = "kvm";
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bsd_kvm_ops.to_longname = _("Kernel memory interface");
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bsd_kvm_ops.to_doc = _("Use a kernel virtual memory image as a target.\n\
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Optionally specify the filename of a core dump.");
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bsd_kvm_ops.to_open = bsd_kvm_open;
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bsd_kvm_ops.to_close = bsd_kvm_close;
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bsd_kvm_ops.to_fetch_registers = bsd_kvm_fetch_registers;
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bsd_kvm_ops.to_xfer_partial = bsd_kvm_xfer_partial;
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bsd_kvm_ops.to_files_info = bsd_kvm_files_info;
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bsd_kvm_ops.to_thread_alive = bsd_kvm_thread_alive;
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bsd_kvm_ops.to_pid_to_str = bsd_kvm_pid_to_str;
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bsd_kvm_ops.to_stratum = process_stratum;
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bsd_kvm_ops.to_has_memory = 1;
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bsd_kvm_ops.to_has_stack = 1;
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bsd_kvm_ops.to_has_registers = 1;
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bsd_kvm_ops.to_magic = OPS_MAGIC;
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add_target (&bsd_kvm_ops);
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add_prefix_cmd ("kvm", class_obscure, bsd_kvm_cmd, _("\
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Generic command for manipulating the kernel memory interface."),
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&bsd_kvm_cmdlist, "kvm ", 0, &cmdlist);
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#ifndef HAVE_STRUCT_THREAD_TD_PCB
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add_cmd ("proc", class_obscure, bsd_kvm_proc_cmd,
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_("Set current context from proc address"), &bsd_kvm_cmdlist);
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#endif
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add_cmd ("pcb", class_obscure, bsd_kvm_pcb_cmd,
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/* i18n: PCB == "Process Control Block" */
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_("Set current context from pcb address"), &bsd_kvm_cmdlist);
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/* Some notes on the ptid usage on this target.
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The pid field represents the kvm inferior instance. Currently,
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we don't support multiple kvm inferiors, but we start at 1
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anyway. The lwp field is set to != 0, in case the core wants to
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refer to the whole kvm inferior with ptid(1,0,0).
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If kvm is made to export running processes as gdb threads,
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the following form can be used:
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ptid (1, 1, 0) -> kvm inferior 1, in kernel
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ptid (1, 1, 1) -> kvm inferior 1, process 1
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ptid (1, 1, 2) -> kvm inferior 1, process 2
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ptid (1, 1, n) -> kvm inferior 1, process n
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*/
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bsd_kvm_ptid = ptid_build (1, 1, 0);
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}
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