/* Low level interface to ptrace, for the remote server for GDB.
- Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002
- Free Software Foundation, Inc.
+ Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+ 2006, 2007 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
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "server.h"
#include "linux-low.h"
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
+#include <errno.h>
+#include <sys/syscall.h>
+#include <sched.h>
+
+#ifndef PTRACE_GETSIGINFO
+# define PTRACE_GETSIGINFO 0x4202
+# define PTRACE_SETSIGINFO 0x4203
+#endif
+
+#ifndef O_LARGEFILE
+#define O_LARGEFILE 0
+#endif
+
+/* If the system headers did not provide the constants, hard-code the normal
+ values. */
+#ifndef PTRACE_EVENT_FORK
+
+#define PTRACE_SETOPTIONS 0x4200
+#define PTRACE_GETEVENTMSG 0x4201
+
+/* options set using PTRACE_SETOPTIONS */
+#define PTRACE_O_TRACESYSGOOD 0x00000001
+#define PTRACE_O_TRACEFORK 0x00000002
+#define PTRACE_O_TRACEVFORK 0x00000004
+#define PTRACE_O_TRACECLONE 0x00000008
+#define PTRACE_O_TRACEEXEC 0x00000010
+#define PTRACE_O_TRACEVFORKDONE 0x00000020
+#define PTRACE_O_TRACEEXIT 0x00000040
+
+/* Wait extended result codes for the above trace options. */
+#define PTRACE_EVENT_FORK 1
+#define PTRACE_EVENT_VFORK 2
+#define PTRACE_EVENT_CLONE 3
+#define PTRACE_EVENT_EXEC 4
+#define PTRACE_EVENT_VFORK_DONE 5
+#define PTRACE_EVENT_EXIT 6
+
+#endif /* PTRACE_EVENT_FORK */
+
+/* We can't always assume that this flag is available, but all systems
+ with the ptrace event handlers also have __WALL, so it's safe to use
+ in some contexts. */
+#ifndef __WALL
+#define __WALL 0x40000000 /* Wait for any child. */
+#endif
+
+#ifdef __UCLIBC__
+#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
+#define HAS_NOMMU
+#endif
+#endif
+
+/* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol
+ representation of the thread ID.
+
+ ``all_processes'' is keyed by the process ID - which on Linux is (presently)
+ the same as the LWP ID. */
+
+struct inferior_list all_processes;
+
+/* A list of all unknown processes which receive stop signals. Some other
+ process will presumably claim each of these as forked children
+ momentarily. */
+
+struct inferior_list stopped_pids;
+
+/* FIXME this is a bit of a hack, and could be removed. */
+int stopping_threads;
+
+/* FIXME make into a target method? */
+int using_threads = 1;
+static int thread_db_active;
+
+static int must_set_ptrace_flags;
+
+static void linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal, siginfo_t *info);
+static void linux_resume (struct thread_resume *resume_info);
+static void stop_all_processes (void);
+static int linux_wait_for_event (struct thread_info *child);
+static int check_removed_breakpoint (struct process_info *event_child);
+static void *add_process (unsigned long pid);
+
+struct pending_signals
+{
+ int signal;
+ siginfo_t info;
+ struct pending_signals *prev;
+};
#define PTRACE_ARG3_TYPE long
#define PTRACE_XFER_TYPE long
static int use_regsets_p = 1;
#endif
-extern int errno;
+#define pid_of(proc) ((proc)->head.id)
+
+/* FIXME: Delete eventually. */
+#define inferior_pid (pid_of (get_thread_process (current_inferior)))
+
+static void
+handle_extended_wait (struct process_info *event_child, int wstat)
+{
+ int event = wstat >> 16;
+ struct process_info *new_process;
+
+ if (event == PTRACE_EVENT_CLONE)
+ {
+ unsigned long new_pid;
+ int ret, status;
+
+ ptrace (PTRACE_GETEVENTMSG, inferior_pid, 0, &new_pid);
+
+ /* If we haven't already seen the new PID stop, wait for it now. */
+ if (! pull_pid_from_list (&stopped_pids, new_pid))
+ {
+ /* The new child has a pending SIGSTOP. We can't affect it until it
+ hits the SIGSTOP, but we're already attached. */
+
+ do {
+ ret = waitpid (new_pid, &status, __WALL);
+ } while (ret == -1 && errno == EINTR);
+
+ if (ret == -1)
+ perror_with_name ("waiting for new child");
+ else if (ret != new_pid)
+ warning ("wait returned unexpected PID %d", ret);
+ else if (!WIFSTOPPED (status))
+ warning ("wait returned unexpected status 0x%x", status);
+ }
+
+ ptrace (PTRACE_SETOPTIONS, new_pid, 0, PTRACE_O_TRACECLONE);
+
+ new_process = (struct process_info *) add_process (new_pid);
+ add_thread (new_pid, new_process, new_pid);
+ new_thread_notify (thread_id_to_gdb_id (new_process->lwpid));
+
+ /* Normally we will get the pending SIGSTOP. But in some cases
+ we might get another signal delivered to the group first.
+ If we do, be sure not to lose it. */
+ if (WSTOPSIG (status) == SIGSTOP)
+ {
+ if (stopping_threads)
+ new_process->stopped = 1;
+ else
+ ptrace (PTRACE_CONT, new_pid, 0, 0);
+ }
+ else
+ {
+ new_process->stop_expected = 1;
+ if (stopping_threads)
+ {
+ new_process->stopped = 1;
+ new_process->status_pending_p = 1;
+ new_process->status_pending = status;
+ }
+ else
+ /* Pass the signal on. This is what GDB does - except
+ shouldn't we really report it instead? */
+ ptrace (PTRACE_CONT, new_pid, 0, WSTOPSIG (status));
+ }
+
+ /* Always resume the current thread. If we are stopping
+ threads, it will have a pending SIGSTOP; we may as well
+ collect it now. */
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping, 0, NULL);
+ }
+}
+
+/* This function should only be called if the process got a SIGTRAP.
+ The SIGTRAP could mean several things.
+
+ On i386, where decr_pc_after_break is non-zero:
+ If we were single-stepping this process using PTRACE_SINGLESTEP,
+ we will get only the one SIGTRAP (even if the instruction we
+ stepped over was a breakpoint). The value of $eip will be the
+ next instruction.
+ If we continue the process using PTRACE_CONT, we will get a
+ SIGTRAP when we hit a breakpoint. The value of $eip will be
+ the instruction after the breakpoint (i.e. needs to be
+ decremented). If we report the SIGTRAP to GDB, we must also
+ report the undecremented PC. If we cancel the SIGTRAP, we
+ must resume at the decremented PC.
+
+ (Presumably, not yet tested) On a non-decr_pc_after_break machine
+ with hardware or kernel single-step:
+ If we single-step over a breakpoint instruction, our PC will
+ point at the following instruction. If we continue and hit a
+ breakpoint instruction, our PC will point at the breakpoint
+ instruction. */
+
+static CORE_ADDR
+get_stop_pc (void)
+{
+ CORE_ADDR stop_pc = (*the_low_target.get_pc) ();
+
+ if (get_thread_process (current_inferior)->stepping)
+ return stop_pc;
+ else
+ return stop_pc - the_low_target.decr_pc_after_break;
+}
+
+static void *
+add_process (unsigned long pid)
+{
+ struct process_info *process;
+
+ process = (struct process_info *) malloc (sizeof (*process));
+ memset (process, 0, sizeof (*process));
+
+ process->head.id = pid;
+ process->lwpid = pid;
+
+ add_inferior_to_list (&all_processes, &process->head);
+
+ return process;
+}
+
+/* Start an inferior process and returns its pid.
+ ALLARGS is a vector of program-name and args. */
+
+static int
+linux_create_inferior (char *program, char **allargs)
+{
+ void *new_process;
+ int pid;
+
+#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+ pid = vfork ();
+#else
+ pid = fork ();
+#endif
+ if (pid < 0)
+ perror_with_name ("fork");
+
+ if (pid == 0)
+ {
+ ptrace (PTRACE_TRACEME, 0, 0, 0);
+
+ signal (__SIGRTMIN + 1, SIG_DFL);
+
+ setpgid (0, 0);
+
+ execv (program, allargs);
+ if (errno == ENOENT)
+ execvp (program, allargs);
+
+ fprintf (stderr, "Cannot exec %s: %s.\n", program,
+ strerror (errno));
+ fflush (stderr);
+ _exit (0177);
+ }
+
+ new_process = add_process (pid);
+ add_thread (pid, new_process, pid);
+ must_set_ptrace_flags = 1;
+
+ return pid;
+}
+
+/* Attach to an inferior process. */
+
+void
+linux_attach_lwp (unsigned long pid)
+{
+ struct process_info *new_process;
+
+ if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
+ {
+ fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
+ strerror (errno), errno);
+ fflush (stderr);
+
+ /* If we fail to attach to an LWP, just return. */
+ if (all_threads.head == NULL)
+ _exit (0177);
+ return;
+ }
+
+ ptrace (PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACECLONE);
+
+ new_process = (struct process_info *) add_process (pid);
+ add_thread (pid, new_process, pid);
+ new_thread_notify (thread_id_to_gdb_id (new_process->lwpid));
+
+ /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
+ brings it to a halt. We should ignore that SIGSTOP and resume the process
+ (unless this is the first process, in which case the flag will be cleared
+ in linux_attach).
+
+ On the other hand, if we are currently trying to stop all threads, we
+ should treat the new thread as if we had sent it a SIGSTOP. This works
+ because we are guaranteed that add_process added us to the end of the
+ list, and so the new thread has not yet reached wait_for_sigstop (but
+ will). */
+ if (! stopping_threads)
+ new_process->stop_expected = 1;
+}
+
+int
+linux_attach (unsigned long pid)
+{
+ struct process_info *process;
+
+ linux_attach_lwp (pid);
+
+ /* Don't ignore the initial SIGSTOP if we just attached to this process.
+ It will be collected by wait shortly. */
+ process = (struct process_info *) find_inferior_id (&all_processes, pid);
+ process->stop_expected = 0;
+
+ return 0;
+}
+
+/* Kill the inferior process. Make us have no inferior. */
+
+static void
+linux_kill_one_process (struct inferior_list_entry *entry)
+{
+ struct thread_info *thread = (struct thread_info *) entry;
+ struct process_info *process = get_thread_process (thread);
+ int wstat;
+
+ /* We avoid killing the first thread here, because of a Linux kernel (at
+ least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
+ the children get a chance to be reaped, it will remain a zombie
+ forever. */
+ if (entry == all_threads.head)
+ return;
+
+ do
+ {
+ ptrace (PTRACE_KILL, pid_of (process), 0, 0);
+
+ /* Make sure it died. The loop is most likely unnecessary. */
+ wstat = linux_wait_for_event (thread);
+ } while (WIFSTOPPED (wstat));
+}
+
+static void
+linux_kill (void)
+{
+ struct thread_info *thread = (struct thread_info *) all_threads.head;
+ struct process_info *process;
+ int wstat;
+
+ if (thread == NULL)
+ return;
+
+ for_each_inferior (&all_threads, linux_kill_one_process);
+
+ /* See the comment in linux_kill_one_process. We did not kill the first
+ thread in the list, so do so now. */
+ process = get_thread_process (thread);
+ do
+ {
+ ptrace (PTRACE_KILL, pid_of (process), 0, 0);
+
+ /* Make sure it died. The loop is most likely unnecessary. */
+ wstat = linux_wait_for_event (thread);
+ } while (WIFSTOPPED (wstat));
+}
+
+static void
+linux_detach_one_process (struct inferior_list_entry *entry)
+{
+ struct thread_info *thread = (struct thread_info *) entry;
+ struct process_info *process = get_thread_process (thread);
+
+ /* Make sure the process isn't stopped at a breakpoint that's
+ no longer there. */
+ check_removed_breakpoint (process);
+
+ /* If this process is stopped but is expecting a SIGSTOP, then make
+ sure we take care of that now. This isn't absolutely guaranteed
+ to collect the SIGSTOP, but is fairly likely to. */
+ if (process->stop_expected)
+ {
+ /* Clear stop_expected, so that the SIGSTOP will be reported. */
+ process->stop_expected = 0;
+ if (process->stopped)
+ linux_resume_one_process (&process->head, 0, 0, NULL);
+ linux_wait_for_event (thread);
+ }
+
+ /* Flush any pending changes to the process's registers. */
+ regcache_invalidate_one ((struct inferior_list_entry *)
+ get_process_thread (process));
+
+ /* Finally, let it resume. */
+ ptrace (PTRACE_DETACH, pid_of (process), 0, 0);
+}
+
+static int
+linux_detach (void)
+{
+ delete_all_breakpoints ();
+ for_each_inferior (&all_threads, linux_detach_one_process);
+ clear_inferiors ();
+ return 0;
+}
+
+static void
+linux_join (void)
+{
+ extern unsigned long signal_pid;
+ int status, ret;
+
+ do {
+ ret = waitpid (signal_pid, &status, 0);
+ if (WIFEXITED (status) || WIFSIGNALED (status))
+ break;
+ } while (ret != -1 || errno != ECHILD);
+}
+
+/* Return nonzero if the given thread is still alive. */
+static int
+linux_thread_alive (unsigned long lwpid)
+{
+ if (find_inferior_id (&all_threads, lwpid) != NULL)
+ return 1;
+ else
+ return 0;
+}
+
+/* Return nonzero if this process stopped at a breakpoint which
+ no longer appears to be inserted. Also adjust the PC
+ appropriately to resume where the breakpoint used to be. */
+static int
+check_removed_breakpoint (struct process_info *event_child)
+{
+ CORE_ADDR stop_pc;
+ struct thread_info *saved_inferior;
+
+ if (event_child->pending_is_breakpoint == 0)
+ return 0;
+
+ if (debug_threads)
+ fprintf (stderr, "Checking for breakpoint in process %ld.\n",
+ event_child->lwpid);
+
+ saved_inferior = current_inferior;
+ current_inferior = get_process_thread (event_child);
+
+ stop_pc = get_stop_pc ();
+
+ /* If the PC has changed since we stopped, then we shouldn't do
+ anything. This happens if, for instance, GDB handled the
+ decr_pc_after_break subtraction itself. */
+ if (stop_pc != event_child->pending_stop_pc)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Ignoring, PC was changed. Old PC was 0x%08llx\n",
+ event_child->pending_stop_pc);
+
+ event_child->pending_is_breakpoint = 0;
+ current_inferior = saved_inferior;
+ return 0;
+ }
+
+ /* If the breakpoint is still there, we will report hitting it. */
+ if ((*the_low_target.breakpoint_at) (stop_pc))
+ {
+ if (debug_threads)
+ fprintf (stderr, "Ignoring, breakpoint is still present.\n");
+ current_inferior = saved_inferior;
+ return 0;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Removed breakpoint.\n");
+
+ /* For decr_pc_after_break targets, here is where we perform the
+ decrement. We go immediately from this function to resuming,
+ and can not safely call get_stop_pc () again. */
+ if (the_low_target.set_pc != NULL)
+ (*the_low_target.set_pc) (stop_pc);
+
+ /* We consumed the pending SIGTRAP. */
+ event_child->pending_is_breakpoint = 0;
+ event_child->status_pending_p = 0;
+ event_child->status_pending = 0;
+
+ current_inferior = saved_inferior;
+ return 1;
+}
+
+/* Return 1 if this process has an interesting status pending. This function
+ may silently resume an inferior process. */
+static int
+status_pending_p (struct inferior_list_entry *entry, void *dummy)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ if (process->status_pending_p)
+ if (check_removed_breakpoint (process))
+ {
+ /* This thread was stopped at a breakpoint, and the breakpoint
+ is now gone. We were told to continue (or step...) all threads,
+ so GDB isn't trying to single-step past this breakpoint.
+ So instead of reporting the old SIGTRAP, pretend we got to
+ the breakpoint just after it was removed instead of just
+ before; resume the process. */
+ linux_resume_one_process (&process->head, 0, 0, NULL);
+ return 0;
+ }
+
+ return process->status_pending_p;
+}
+
+static void
+linux_wait_for_process (struct process_info **childp, int *wstatp)
+{
+ int ret;
+ int to_wait_for = -1;
+
+ if (*childp != NULL)
+ to_wait_for = (*childp)->lwpid;
+
+retry:
+ while (1)
+ {
+ ret = waitpid (to_wait_for, wstatp, WNOHANG);
+
+ if (ret == -1)
+ {
+ if (errno != ECHILD)
+ perror_with_name ("waitpid");
+ }
+ else if (ret > 0)
+ break;
+
+ ret = waitpid (to_wait_for, wstatp, WNOHANG | __WCLONE);
+
+ if (ret == -1)
+ {
+ if (errno != ECHILD)
+ perror_with_name ("waitpid (WCLONE)");
+ }
+ else if (ret > 0)
+ break;
+
+ usleep (1000);
+ }
+
+ if (debug_threads
+ && (!WIFSTOPPED (*wstatp)
+ || (WSTOPSIG (*wstatp) != 32
+ && WSTOPSIG (*wstatp) != 33)))
+ fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);
+
+ if (to_wait_for == -1)
+ *childp = (struct process_info *) find_inferior_id (&all_processes, ret);
+
+ /* If we didn't find a process, one of two things presumably happened:
+ - A process we started and then detached from has exited. Ignore it.
+ - A process we are controlling has forked and the new child's stop
+ was reported to us by the kernel. Save its PID. */
+ if (*childp == NULL && WIFSTOPPED (*wstatp))
+ {
+ add_pid_to_list (&stopped_pids, ret);
+ goto retry;
+ }
+ else if (*childp == NULL)
+ goto retry;
+
+ (*childp)->stopped = 1;
+ (*childp)->pending_is_breakpoint = 0;
+
+ (*childp)->last_status = *wstatp;
+
+ if (debug_threads
+ && WIFSTOPPED (*wstatp))
+ {
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, (*childp)->lwpid);
+ /* For testing only; i386_stop_pc prints out a diagnostic. */
+ if (the_low_target.get_pc != NULL)
+ get_stop_pc ();
+ }
+}
+
+static int
+linux_wait_for_event (struct thread_info *child)
+{
+ CORE_ADDR stop_pc;
+ struct process_info *event_child;
+ int wstat;
+
+ /* Check for a process with a pending status. */
+ /* It is possible that the user changed the pending task's registers since
+ it stopped. We correctly handle the change of PC if we hit a breakpoint
+ (in check_removed_breakpoint); signals should be reported anyway. */
+ if (child == NULL)
+ {
+ event_child = (struct process_info *)
+ find_inferior (&all_processes, status_pending_p, NULL);
+ if (debug_threads && event_child)
+ fprintf (stderr, "Got a pending child %ld\n", event_child->lwpid);
+ }
+ else
+ {
+ event_child = get_thread_process (child);
+ if (event_child->status_pending_p
+ && check_removed_breakpoint (event_child))
+ event_child = NULL;
+ }
+
+ if (event_child != NULL)
+ {
+ if (event_child->status_pending_p)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Got an event from pending child %ld (%04x)\n",
+ event_child->lwpid, event_child->status_pending);
+ wstat = event_child->status_pending;
+ event_child->status_pending_p = 0;
+ event_child->status_pending = 0;
+ current_inferior = get_process_thread (event_child);
+ return wstat;
+ }
+ }
+
+ /* We only enter this loop if no process has a pending wait status. Thus
+ any action taken in response to a wait status inside this loop is
+ responding as soon as we detect the status, not after any pending
+ events. */
+ while (1)
+ {
+ if (child == NULL)
+ event_child = NULL;
+ else
+ event_child = get_thread_process (child);
+
+ linux_wait_for_process (&event_child, &wstat);
+
+ if (event_child == NULL)
+ error ("event from unknown child");
+
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, event_child->lwpid);
+
+ /* Check for thread exit. */
+ if (! WIFSTOPPED (wstat))
+ {
+ if (debug_threads)
+ fprintf (stderr, "LWP %ld exiting\n", event_child->head.id);
+
+ /* If the last thread is exiting, just return. */
+ if (all_threads.head == all_threads.tail)
+ return wstat;
+
+ dead_thread_notify (thread_id_to_gdb_id (event_child->lwpid));
+
+ remove_inferior (&all_processes, &event_child->head);
+ free (event_child);
+ remove_thread (current_inferior);
+ current_inferior = (struct thread_info *) all_threads.head;
+
+ /* If we were waiting for this particular child to do something...
+ well, it did something. */
+ if (child != NULL)
+ return wstat;
+
+ /* Wait for a more interesting event. */
+ continue;
+ }
+
+ if (WIFSTOPPED (wstat)
+ && WSTOPSIG (wstat) == SIGSTOP
+ && event_child->stop_expected)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Expected stop.\n");
+ event_child->stop_expected = 0;
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping, 0, NULL);
+ continue;
+ }
+
+ if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP
+ && wstat >> 16 != 0)
+ {
+ handle_extended_wait (event_child, wstat);
+ continue;
+ }
+
+ /* If GDB is not interested in this signal, don't stop other
+ threads, and don't report it to GDB. Just resume the
+ inferior right away. We do this for threading-related
+ signals as well as any that GDB specifically requested we
+ ignore. But never ignore SIGSTOP if we sent it ourselves,
+ and do not ignore signals when stepping - they may require
+ special handling to skip the signal handler. */
+ /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
+ thread library? */
+ if (WIFSTOPPED (wstat)
+ && !event_child->stepping
+ && (
+#ifdef USE_THREAD_DB
+ (thread_db_active && (WSTOPSIG (wstat) == __SIGRTMIN
+ || WSTOPSIG (wstat) == __SIGRTMIN + 1))
+ ||
+#endif
+ (pass_signals[target_signal_from_host (WSTOPSIG (wstat))]
+ && (WSTOPSIG (wstat) != SIGSTOP || !stopping_threads))))
+ {
+ siginfo_t info, *info_p;
+
+ if (debug_threads)
+ fprintf (stderr, "Ignored signal %d for LWP %ld.\n",
+ WSTOPSIG (wstat), event_child->head.id);
+
+ if (ptrace (PTRACE_GETSIGINFO, event_child->lwpid, 0, &info) == 0)
+ info_p = &info;
+ else
+ info_p = NULL;
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping,
+ WSTOPSIG (wstat), info_p);
+ continue;
+ }
+
+ /* If this event was not handled above, and is not a SIGTRAP, report
+ it. */
+ if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP)
+ return wstat;
+
+ /* If this target does not support breakpoints, we simply report the
+ SIGTRAP; it's of no concern to us. */
+ if (the_low_target.get_pc == NULL)
+ return wstat;
+
+ stop_pc = get_stop_pc ();
+
+ /* bp_reinsert will only be set if we were single-stepping.
+ Notice that we will resume the process after hitting
+ a gdbserver breakpoint; single-stepping to/over one
+ is not supported (yet). */
+ if (event_child->bp_reinsert != 0)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Reinserted breakpoint.\n");
+ reinsert_breakpoint (event_child->bp_reinsert);
+ event_child->bp_reinsert = 0;
+
+ /* Clear the single-stepping flag and SIGTRAP as we resume. */
+ linux_resume_one_process (&event_child->head, 0, 0, NULL);
+ continue;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Hit a (non-reinsert) breakpoint.\n");
+
+ if (check_breakpoints (stop_pc) != 0)
+ {
+ /* We hit one of our own breakpoints. We mark it as a pending
+ breakpoint, so that check_removed_breakpoint () will do the PC
+ adjustment for us at the appropriate time. */
+ event_child->pending_is_breakpoint = 1;
+ event_child->pending_stop_pc = stop_pc;
+
+ /* Now we need to put the breakpoint back. We continue in the event
+ loop instead of simply replacing the breakpoint right away,
+ in order to not lose signals sent to the thread that hit the
+ breakpoint. Unfortunately this increases the window where another
+ thread could sneak past the removed breakpoint. For the current
+ use of server-side breakpoints (thread creation) this is
+ acceptable; but it needs to be considered before this breakpoint
+ mechanism can be used in more general ways. For some breakpoints
+ it may be necessary to stop all other threads, but that should
+ be avoided where possible.
+
+ If breakpoint_reinsert_addr is NULL, that means that we can
+ use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint,
+ mark it for reinsertion, and single-step.
+
+ Otherwise, call the target function to figure out where we need
+ our temporary breakpoint, create it, and continue executing this
+ process. */
+ if (the_low_target.breakpoint_reinsert_addr == NULL)
+ {
+ event_child->bp_reinsert = stop_pc;
+ uninsert_breakpoint (stop_pc);
+ linux_resume_one_process (&event_child->head, 1, 0, NULL);
+ }
+ else
+ {
+ reinsert_breakpoint_by_bp
+ (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
+ linux_resume_one_process (&event_child->head, 0, 0, NULL);
+ }
+
+ continue;
+ }
+
+ /* If we were single-stepping, we definitely want to report the
+ SIGTRAP. The single-step operation has completed, so also
+ clear the stepping flag; in general this does not matter,
+ because the SIGTRAP will be reported to the client, which
+ will give us a new action for this thread, but clear it for
+ consistency anyway. It's safe to clear the stepping flag
+ because the only consumer of get_stop_pc () after this point
+ is check_removed_breakpoint, and pending_is_breakpoint is not
+ set. It might be wiser to use a step_completed flag instead. */
+ if (event_child->stepping)
+ {
+ event_child->stepping = 0;
+ return wstat;
+ }
+
+ /* A SIGTRAP that we can't explain. It may have been a breakpoint.
+ Check if it is a breakpoint, and if so mark the process information
+ accordingly. This will handle both the necessary fiddling with the
+ PC on decr_pc_after_break targets and suppressing extra threads
+ hitting a breakpoint if two hit it at once and then GDB removes it
+ after the first is reported. Arguably it would be better to report
+ multiple threads hitting breakpoints simultaneously, but the current
+ remote protocol does not allow this. */
+ if ((*the_low_target.breakpoint_at) (stop_pc))
+ {
+ event_child->pending_is_breakpoint = 1;
+ event_child->pending_stop_pc = stop_pc;
+ }
+
+ return wstat;
+ }
+
+ /* NOTREACHED */
+ return 0;
+}
+
+/* Wait for process, returns status. */
+
+static unsigned char
+linux_wait (char *status)
+{
+ int w;
+ struct thread_info *child = NULL;
+
+retry:
+ /* If we were only supposed to resume one thread, only wait for
+ that thread - if it's still alive. If it died, however - which
+ can happen if we're coming from the thread death case below -
+ then we need to make sure we restart the other threads. We could
+ pick a thread at random or restart all; restarting all is less
+ arbitrary. */
+ if (cont_thread != 0 && cont_thread != -1)
+ {
+ child = (struct thread_info *) find_inferior_id (&all_threads,
+ cont_thread);
+
+ /* No stepping, no signal - unless one is pending already, of course. */
+ if (child == NULL)
+ {
+ struct thread_resume resume_info;
+ resume_info.thread = -1;
+ resume_info.step = resume_info.sig = resume_info.leave_stopped = 0;
+ linux_resume (&resume_info);
+ }
+ }
+
+ enable_async_io ();
+ unblock_async_io ();
+ w = linux_wait_for_event (child);
+ stop_all_processes ();
+ disable_async_io ();
+
+ if (must_set_ptrace_flags)
+ {
+ ptrace (PTRACE_SETOPTIONS, inferior_pid, 0, PTRACE_O_TRACECLONE);
+ must_set_ptrace_flags = 0;
+ }
+
+ /* If we are waiting for a particular child, and it exited,
+ linux_wait_for_event will return its exit status. Similarly if
+ the last child exited. If this is not the last child, however,
+ do not report it as exited until there is a 'thread exited' response
+ available in the remote protocol. Instead, just wait for another event.
+ This should be safe, because if the thread crashed we will already
+ have reported the termination signal to GDB; that should stop any
+ in-progress stepping operations, etc.
+
+ Report the exit status of the last thread to exit. This matches
+ LinuxThreads' behavior. */
+
+ if (all_threads.head == all_threads.tail)
+ {
+ if (WIFEXITED (w))
+ {
+ fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
+ *status = 'W';
+ clear_inferiors ();
+ free (all_processes.head);
+ all_processes.head = all_processes.tail = NULL;
+ return WEXITSTATUS (w);
+ }
+ else if (!WIFSTOPPED (w))
+ {
+ fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
+ *status = 'X';
+ clear_inferiors ();
+ free (all_processes.head);
+ all_processes.head = all_processes.tail = NULL;
+ return target_signal_from_host (WTERMSIG (w));
+ }
+ }
+ else
+ {
+ if (!WIFSTOPPED (w))
+ goto retry;
+ }
+
+ *status = 'T';
+ return target_signal_from_host (WSTOPSIG (w));
+}
+
+/* Send a signal to an LWP. For LinuxThreads, kill is enough; however, if
+ thread groups are in use, we need to use tkill. */
+
+static int
+kill_lwp (unsigned long lwpid, int signo)
+{
+ static int tkill_failed;
+
+ errno = 0;
+
+#ifdef SYS_tkill
+ if (!tkill_failed)
+ {
+ int ret = syscall (SYS_tkill, lwpid, signo);
+ if (errno != ENOSYS)
+ return ret;
+ errno = 0;
+ tkill_failed = 1;
+ }
+#endif
+
+ return kill (lwpid, signo);
+}
+
+static void
+send_sigstop (struct inferior_list_entry *entry)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ if (process->stopped)
+ return;
+
+ /* If we already have a pending stop signal for this process, don't
+ send another. */
+ if (process->stop_expected)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Have pending sigstop for process %ld\n",
+ process->lwpid);
+
+ /* We clear the stop_expected flag so that wait_for_sigstop
+ will receive the SIGSTOP event (instead of silently resuming and
+ waiting again). It'll be reset below. */
+ process->stop_expected = 0;
+ return;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Sending sigstop to process %ld\n", process->head.id);
+
+ kill_lwp (process->head.id, SIGSTOP);
+}
+
+static void
+wait_for_sigstop (struct inferior_list_entry *entry)
+{
+ struct process_info *process = (struct process_info *) entry;
+ struct thread_info *saved_inferior, *thread;
+ int wstat;
+ unsigned long saved_tid;
+
+ if (process->stopped)
+ return;
+
+ saved_inferior = current_inferior;
+ saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
+ thread = (struct thread_info *) find_inferior_id (&all_threads,
+ process->lwpid);
+ wstat = linux_wait_for_event (thread);
+
+ /* If we stopped with a non-SIGSTOP signal, save it for later
+ and record the pending SIGSTOP. If the process exited, just
+ return. */
+ if (WIFSTOPPED (wstat)
+ && WSTOPSIG (wstat) != SIGSTOP)
+ {
+ if (debug_threads)
+ fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
+ process->lwpid, wstat);
+ process->status_pending_p = 1;
+ process->status_pending = wstat;
+ process->stop_expected = 1;
+ }
-#ifdef HAVE_LINUX_USRREGS
-extern int num_regs;
-extern int regmap[];
-#endif
+ if (linux_thread_alive (saved_tid))
+ current_inferior = saved_inferior;
+ else
+ {
+ if (debug_threads)
+ fprintf (stderr, "Previously current thread died.\n");
-static int inferior_pid;
+ /* Set a valid thread as current. */
+ set_desired_inferior (0);
+ }
+}
-/* Start an inferior process and returns its pid.
- ALLARGS is a vector of program-name and args. */
+static void
+stop_all_processes (void)
+{
+ stopping_threads = 1;
+ for_each_inferior (&all_processes, send_sigstop);
+ for_each_inferior (&all_processes, wait_for_sigstop);
+ stopping_threads = 0;
+}
-static int
-linux_create_inferior (char *program, char **allargs)
+/* Resume execution of the inferior process.
+ If STEP is nonzero, single-step it.
+ If SIGNAL is nonzero, give it that signal. */
+
+static void
+linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal, siginfo_t *info)
{
- int pid;
+ struct process_info *process = (struct process_info *) entry;
+ struct thread_info *saved_inferior;
- pid = fork ();
- if (pid < 0)
- perror_with_name ("fork");
+ if (process->stopped == 0)
+ return;
- if (pid == 0)
+ /* If we have pending signals or status, and a new signal, enqueue the
+ signal. Also enqueue the signal if we are waiting to reinsert a
+ breakpoint; it will be picked up again below. */
+ if (signal != 0
+ && (process->status_pending_p || process->pending_signals != NULL
+ || process->bp_reinsert != 0))
{
- ptrace (PTRACE_TRACEME, 0, 0, 0);
+ struct pending_signals *p_sig;
+ p_sig = malloc (sizeof (*p_sig));
+ p_sig->prev = process->pending_signals;
+ p_sig->signal = signal;
+ if (info == NULL)
+ memset (&p_sig->info, 0, sizeof (siginfo_t));
+ else
+ memcpy (&p_sig->info, info, sizeof (siginfo_t));
+ process->pending_signals = p_sig;
+ }
- execv (program, allargs);
+ if (process->status_pending_p && !check_removed_breakpoint (process))
+ return;
- fprintf (stderr, "Cannot exec %s: %s.\n", program,
- strerror (errno));
- fflush (stderr);
- _exit (0177);
+ saved_inferior = current_inferior;
+ current_inferior = get_process_thread (process);
+
+ if (debug_threads)
+ fprintf (stderr, "Resuming process %ld (%s, signal %d, stop %s)\n", inferior_pid,
+ step ? "step" : "continue", signal,
+ process->stop_expected ? "expected" : "not expected");
+
+ /* This bit needs some thinking about. If we get a signal that
+ we must report while a single-step reinsert is still pending,
+ we often end up resuming the thread. It might be better to
+ (ew) allow a stack of pending events; then we could be sure that
+ the reinsert happened right away and not lose any signals.
+
+ Making this stack would also shrink the window in which breakpoints are
+ uninserted (see comment in linux_wait_for_process) but not enough for
+ complete correctness, so it won't solve that problem. It may be
+ worthwhile just to solve this one, however. */
+ if (process->bp_reinsert != 0)
+ {
+ if (debug_threads)
+ fprintf (stderr, " pending reinsert at %08lx", (long)process->bp_reinsert);
+ if (step == 0)
+ fprintf (stderr, "BAD - reinserting but not stepping.\n");
+ step = 1;
+
+ /* Postpone any pending signal. It was enqueued above. */
+ signal = 0;
}
- add_inferior (pid);
- /* FIXME remove */
- inferior_pid = pid;
- return 0;
-}
+ check_removed_breakpoint (process);
-/* Attach to an inferior process. */
+ if (debug_threads && the_low_target.get_pc != NULL)
+ {
+ fprintf (stderr, " ");
+ (*the_low_target.get_pc) ();
+ }
-static int
-linux_attach (int pid)
-{
- if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
+ /* If we have pending signals, consume one unless we are trying to reinsert
+ a breakpoint. */
+ if (process->pending_signals != NULL && process->bp_reinsert == 0)
{
- fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid,
- errno < sys_nerr ? sys_errlist[errno] : "unknown error",
- errno);
- fflush (stderr);
- _exit (0177);
+ struct pending_signals **p_sig;
+
+ p_sig = &process->pending_signals;
+ while ((*p_sig)->prev != NULL)
+ p_sig = &(*p_sig)->prev;
+
+ signal = (*p_sig)->signal;
+ if ((*p_sig)->info.si_signo != 0)
+ ptrace (PTRACE_SETSIGINFO, process->lwpid, 0, &(*p_sig)->info);
+
+ free (*p_sig);
+ *p_sig = NULL;
}
- return 0;
+ regcache_invalidate_one ((struct inferior_list_entry *)
+ get_process_thread (process));
+ errno = 0;
+ process->stopped = 0;
+ process->stepping = step;
+ ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, process->lwpid, 0, signal);
+
+ current_inferior = saved_inferior;
+ if (errno)
+ perror_with_name ("ptrace");
}
-/* Kill the inferior process. Make us have no inferior. */
+static struct thread_resume *resume_ptr;
+/* This function is called once per thread. We look up the thread
+ in RESUME_PTR, and mark the thread with a pointer to the appropriate
+ resume request.
+
+ This algorithm is O(threads * resume elements), but resume elements
+ is small (and will remain small at least until GDB supports thread
+ suspension). */
static void
-linux_kill (void)
+linux_set_resume_request (struct inferior_list_entry *entry)
{
- if (inferior_pid == 0)
- return;
- ptrace (PTRACE_KILL, inferior_pid, 0, 0);
- wait (0);
- clear_inferiors ();
+ struct process_info *process;
+ struct thread_info *thread;
+ int ndx;
+
+ thread = (struct thread_info *) entry;
+ process = get_thread_process (thread);
+
+ ndx = 0;
+ while (resume_ptr[ndx].thread != -1 && resume_ptr[ndx].thread != entry->id)
+ ndx++;
+
+ process->resume = &resume_ptr[ndx];
}
-/* Return nonzero if the given thread is still alive. */
-static int
-linux_thread_alive (int pid)
+/* This function is called once per thread. We check the thread's resume
+ request, which will tell us whether to resume, step, or leave the thread
+ stopped; and what signal, if any, it should be sent. For threads which
+ we aren't explicitly told otherwise, we preserve the stepping flag; this
+ is used for stepping over gdbserver-placed breakpoints. */
+
+static void
+linux_continue_one_thread (struct inferior_list_entry *entry)
{
- return 1;
+ struct process_info *process;
+ struct thread_info *thread;
+ int step;
+
+ thread = (struct thread_info *) entry;
+ process = get_thread_process (thread);
+
+ if (process->resume->leave_stopped)
+ return;
+
+ if (process->resume->thread == -1)
+ step = process->stepping || process->resume->step;
+ else
+ step = process->resume->step;
+
+ linux_resume_one_process (&process->head, step, process->resume->sig, NULL);
+
+ process->resume = NULL;
}
-/* Wait for process, returns status */
+/* This function is called once per thread. We check the thread's resume
+ request, which will tell us whether to resume, step, or leave the thread
+ stopped; and what signal, if any, it should be sent. We queue any needed
+ signals, since we won't actually resume. We already have a pending event
+ to report, so we don't need to preserve any step requests; they should
+ be re-issued if necessary. */
-static unsigned char
-linux_wait (char *status)
+static void
+linux_queue_one_thread (struct inferior_list_entry *entry)
{
- int pid;
- int w;
+ struct process_info *process;
+ struct thread_info *thread;
- enable_async_io ();
- pid = waitpid (inferior_pid, &w, 0);
- disable_async_io ();
- if (pid != inferior_pid)
- perror_with_name ("wait");
+ thread = (struct thread_info *) entry;
+ process = get_thread_process (thread);
- if (WIFEXITED (w))
- {
- fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
- *status = 'W';
- clear_inferiors ();
- return ((unsigned char) WEXITSTATUS (w));
- }
- else if (!WIFSTOPPED (w))
+ if (process->resume->leave_stopped)
+ return;
+
+ /* If we have a new signal, enqueue the signal. */
+ if (process->resume->sig != 0)
{
- fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
- clear_inferiors ();
- *status = 'X';
- return ((unsigned char) WTERMSIG (w));
+ struct pending_signals *p_sig;
+ p_sig = malloc (sizeof (*p_sig));
+ p_sig->prev = process->pending_signals;
+ p_sig->signal = process->resume->sig;
+ memset (&p_sig->info, 0, sizeof (siginfo_t));
+
+ /* If this is the same signal we were previously stopped by,
+ make sure to queue its siginfo. We can ignore the return
+ value of ptrace; if it fails, we'll skip
+ PTRACE_SETSIGINFO. */
+ if (WIFSTOPPED (process->last_status)
+ && WSTOPSIG (process->last_status) == process->resume->sig)
+ ptrace (PTRACE_GETSIGINFO, process->lwpid, 0, &p_sig->info);
+
+ process->pending_signals = p_sig;
}
- fetch_inferior_registers (0);
-
- *status = 'T';
- return ((unsigned char) WSTOPSIG (w));
+ process->resume = NULL;
}
-/* Resume execution of the inferior process.
- If STEP is nonzero, single-step it.
- If SIGNAL is nonzero, give it that signal. */
+/* Set DUMMY if this process has an interesting status pending. */
+static int
+resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ /* Processes which will not be resumed are not interesting, because
+ we might not wait for them next time through linux_wait. */
+ if (process->resume->leave_stopped)
+ return 0;
+
+ /* If this thread has a removed breakpoint, we won't have any
+ events to report later, so check now. check_removed_breakpoint
+ may clear status_pending_p. We avoid calling check_removed_breakpoint
+ for any thread that we are not otherwise going to resume - this
+ lets us preserve stopped status when two threads hit a breakpoint.
+ GDB removes the breakpoint to single-step a particular thread
+ past it, then re-inserts it and resumes all threads. We want
+ to report the second thread without resuming it in the interim. */
+ if (process->status_pending_p)
+ check_removed_breakpoint (process);
+
+ if (process->status_pending_p)
+ * (int *) flag_p = 1;
+
+ return 0;
+}
static void
-linux_resume (int step, int signal)
+linux_resume (struct thread_resume *resume_info)
{
- errno = 0;
- ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
- if (errno)
- perror_with_name ("ptrace");
-}
+ int pending_flag;
+ /* Yes, the use of a global here is rather ugly. */
+ resume_ptr = resume_info;
-#ifdef HAVE_LINUX_USRREGS
+ for_each_inferior (&all_threads, linux_set_resume_request);
+
+ /* If there is a thread which would otherwise be resumed, which
+ has a pending status, then don't resume any threads - we can just
+ report the pending status. Make sure to queue any signals
+ that would otherwise be sent. */
+ pending_flag = 0;
+ find_inferior (&all_processes, resume_status_pending_p, &pending_flag);
+
+ if (debug_threads)
+ {
+ if (pending_flag)
+ fprintf (stderr, "Not resuming, pending status\n");
+ else
+ fprintf (stderr, "Resuming, no pending status\n");
+ }
+
+ if (pending_flag)
+ for_each_inferior (&all_threads, linux_queue_one_thread);
+ else
+ {
+ block_async_io ();
+ enable_async_io ();
+ for_each_inferior (&all_threads, linux_continue_one_thread);
+ }
+}
-#define REGISTER_RAW_SIZE(regno) register_size((regno))
+#ifdef HAVE_LINUX_USRREGS
int
register_addr (int regnum)
{
int addr;
- if (regnum < 0 || regnum >= num_regs)
+ if (regnum < 0 || regnum >= the_low_target.num_regs)
error ("Invalid register number %d.", regnum);
- addr = regmap[regnum];
- if (addr == -1)
- addr = 0;
+ addr = the_low_target.regmap[regnum];
return addr;
}
fetch_register (int regno)
{
CORE_ADDR regaddr;
- register int i;
+ int i, size;
+ char *buf;
- if (regno >= num_regs)
+ if (regno >= the_low_target.num_regs)
return;
- if (cannot_fetch_register (regno))
+ if ((*the_low_target.cannot_fetch_register) (regno))
return;
regaddr = register_addr (regno);
if (regaddr == -1)
return;
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
+ size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
+ & - sizeof (PTRACE_XFER_TYPE);
+ buf = alloca (size);
+ for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
- *(PTRACE_XFER_TYPE *) (register_data (regno) + i) =
+ *(PTRACE_XFER_TYPE *) (buf + i) =
ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
regaddr += sizeof (PTRACE_XFER_TYPE);
if (errno != 0)
goto error_exit;
}
}
+ if (the_low_target.left_pad_xfer
+ && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
+ supply_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
+ - register_size (regno)));
+ else
+ supply_register (regno, buf);
+
error_exit:;
}
usr_fetch_inferior_registers (int regno)
{
if (regno == -1 || regno == 0)
- for (regno = 0; regno < num_regs; regno++)
+ for (regno = 0; regno < the_low_target.num_regs; regno++)
fetch_register (regno);
else
fetch_register (regno);
usr_store_inferior_registers (int regno)
{
CORE_ADDR regaddr;
- int i;
+ int i, size;
+ char *buf;
if (regno >= 0)
{
- if (regno >= num_regs)
+ if (regno >= the_low_target.num_regs)
return;
- if (cannot_store_register (regno))
+ if ((*the_low_target.cannot_store_register) (regno) == 1)
return;
regaddr = register_addr (regno);
if (regaddr == -1)
return;
errno = 0;
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
+ size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
+ & - sizeof (PTRACE_XFER_TYPE);
+ buf = alloca (size);
+ memset (buf, 0, size);
+ if (the_low_target.left_pad_xfer
+ && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
+ collect_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
+ - register_size (regno)));
+ else
+ collect_register (regno, buf);
+ for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
- *(int *) (register_data (regno) + i));
+ *(PTRACE_XFER_TYPE *) (buf + i));
if (errno != 0)
{
- /* Warning, not error, in case we are attached; sometimes the
- kernel doesn't let us at the registers. */
- char *err = strerror (errno);
- char *msg = alloca (strlen (err) + 128);
- sprintf (msg, "writing register %d: %s",
- regno, err);
- error (msg);
- return;
+ if ((*the_low_target.cannot_store_register) (regno) == 0)
+ {
+ char *err = strerror (errno);
+ char *msg = alloca (strlen (err) + 128);
+ sprintf (msg, "writing register %d: %s",
+ regno, err);
+ error (msg);
+ return;
+ }
}
- regaddr += sizeof (int);
+ regaddr += sizeof (PTRACE_XFER_TYPE);
}
}
else
- for (regno = 0; regno < num_regs; regno++)
- store_inferior_registers (regno);
+ for (regno = 0; regno < the_low_target.num_regs; regno++)
+ usr_store_inferior_registers (regno);
}
#endif /* HAVE_LINUX_USRREGS */
#ifdef HAVE_LINUX_REGSETS
static int
-regsets_fetch_inferior_registers (void)
+regsets_fetch_inferior_registers ()
{
struct regset_info *regset;
+ int saw_general_regs = 0;
regset = target_regsets;
}
buf = malloc (regset->size);
- res = ptrace (regset->get_request, inferior_pid, 0, (int) buf);
+ res = ptrace (regset->get_request, inferior_pid, 0, buf);
if (res < 0)
{
if (errno == EIO)
}
else
{
- perror ("Warning: ptrace(regsets_fetch_inferior_registers)");
+ char s[256];
+ sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%ld",
+ inferior_pid);
+ perror (s);
}
}
+ else if (regset->type == GENERAL_REGS)
+ saw_general_regs = 1;
regset->store_function (buf);
regset ++;
}
- return 0;
+ if (saw_general_regs)
+ return 0;
+ else
+ return 1;
}
static int
-regsets_store_inferior_registers (void)
+regsets_store_inferior_registers ()
{
struct regset_info *regset;
+ int saw_general_regs = 0;
regset = target_regsets;
}
buf = malloc (regset->size);
- regset->fill_function (buf);
- res = ptrace (regset->set_request, inferior_pid, 0, (int) buf);
+
+ /* First fill the buffer with the current register set contents,
+ in case there are any items in the kernel's regset that are
+ not in gdbserver's regcache. */
+ res = ptrace (regset->get_request, inferior_pid, 0, buf);
+
+ if (res == 0)
+ {
+ /* Then overlay our cached registers on that. */
+ regset->fill_function (buf);
+
+ /* Only now do we write the register set. */
+ res = ptrace (regset->set_request, inferior_pid, 0, buf);
+ }
+
if (res < 0)
{
if (errno == EIO)
perror ("Warning: ptrace(regsets_store_inferior_registers)");
}
}
+ else if (regset->type == GENERAL_REGS)
+ saw_general_regs = 1;
regset ++;
+ free (buf);
}
+ if (saw_general_regs)
+ return 0;
+ else
+ return 1;
return 0;
}
/* Copy LEN bytes from inferior's memory starting at MEMADDR
to debugger memory starting at MYADDR. */
-static void
-linux_read_memory (CORE_ADDR memaddr, char *myaddr, int len)
+static int
+linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
{
register int i;
/* Round starting address down to longword boundary. */
register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
/* Round ending address up; get number of longwords that makes. */
- register int count
- = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
+ register int count
+ = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
/ sizeof (PTRACE_XFER_TYPE);
/* Allocate buffer of that many longwords. */
- register PTRACE_XFER_TYPE *buffer
+ register PTRACE_XFER_TYPE *buffer
= (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
+ int fd;
+ char filename[64];
+
+ /* Try using /proc. Don't bother for one word. */
+ if (len >= 3 * sizeof (long))
+ {
+ /* We could keep this file open and cache it - possibly one per
+ thread. That requires some juggling, but is even faster. */
+ sprintf (filename, "/proc/%ld/mem", inferior_pid);
+ fd = open (filename, O_RDONLY | O_LARGEFILE);
+ if (fd == -1)
+ goto no_proc;
+
+ /* If pread64 is available, use it. It's faster if the kernel
+ supports it (only one syscall), and it's 64-bit safe even on
+ 32-bit platforms (for instance, SPARC debugging a SPARC64
+ application). */
+#ifdef HAVE_PREAD64
+ if (pread64 (fd, myaddr, len, memaddr) != len)
+#else
+ if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, memaddr, len) != len)
+#endif
+ {
+ close (fd);
+ goto no_proc;
+ }
+
+ close (fd);
+ return 0;
+ }
+ no_proc:
/* Read all the longwords */
for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
{
+ errno = 0;
buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
+ if (errno)
+ return errno;
}
/* Copy appropriate bytes out of the buffer. */
memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len);
+
+ return 0;
}
/* Copy LEN bytes of data from debugger memory at MYADDR
returns the value of errno. */
static int
-linux_write_memory (CORE_ADDR memaddr, char *myaddr, int len)
+linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
{
register int i;
/* Round starting address down to longword boundary. */
register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
extern int errno;
+ if (debug_threads)
+ {
+ fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr);
+ }
+
/* Fill start and end extra bytes of buffer with existing memory data. */
buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid,
return 0;
}
-\f
+
+static int linux_supports_tracefork_flag;
+
+/* Helper functions for linux_test_for_tracefork, called via clone (). */
+
+static int
+linux_tracefork_grandchild (void *arg)
+{
+ _exit (0);
+}
+
+static int
+linux_tracefork_child (void *arg)
+{
+ ptrace (PTRACE_TRACEME, 0, 0, 0);
+ kill (getpid (), SIGSTOP);
+ clone (linux_tracefork_grandchild, arg, CLONE_VM | SIGCHLD, NULL);
+ _exit (0);
+}
+
+/* Wrapper function for waitpid which handles EINTR. */
+
+static int
+my_waitpid (int pid, int *status, int flags)
+{
+ int ret;
+ do
+ {
+ ret = waitpid (pid, status, flags);
+ }
+ while (ret == -1 && errno == EINTR);
+
+ return ret;
+}
+
+/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events. Make
+ sure that we can enable the option, and that it had the desired
+ effect. */
+
+static void
+linux_test_for_tracefork (void)
+{
+ int child_pid, ret, status;
+ long second_pid;
+ char *stack = malloc (8192);
+
+ linux_supports_tracefork_flag = 0;
+
+ /* Use CLONE_VM instead of fork, to support uClinux (no MMU). */
+ child_pid = clone (linux_tracefork_child, stack + 2048,
+ CLONE_VM | SIGCHLD, stack + 6144);
+ if (child_pid == -1)
+ perror_with_name ("clone");
+
+ ret = my_waitpid (child_pid, &status, 0);
+ if (ret == -1)
+ perror_with_name ("waitpid");
+ else if (ret != child_pid)
+ error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret);
+ if (! WIFSTOPPED (status))
+ error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status);
+
+ ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
+ if (ret != 0)
+ {
+ ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
+ if (ret != 0)
+ {
+ warning ("linux_test_for_tracefork: failed to kill child");
+ return;
+ }
+
+ ret = my_waitpid (child_pid, &status, 0);
+ if (ret != child_pid)
+ warning ("linux_test_for_tracefork: failed to wait for killed child");
+ else if (!WIFSIGNALED (status))
+ warning ("linux_test_for_tracefork: unexpected wait status 0x%x from "
+ "killed child", status);
+
+ return;
+ }
+
+ ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
+ if (ret != 0)
+ warning ("linux_test_for_tracefork: failed to resume child");
+
+ ret = my_waitpid (child_pid, &status, 0);
+
+ if (ret == child_pid && WIFSTOPPED (status)
+ && status >> 16 == PTRACE_EVENT_FORK)
+ {
+ second_pid = 0;
+ ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
+ if (ret == 0 && second_pid != 0)
+ {
+ int second_status;
+
+ linux_supports_tracefork_flag = 1;
+ my_waitpid (second_pid, &second_status, 0);
+ ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
+ if (ret != 0)
+ warning ("linux_test_for_tracefork: failed to kill second child");
+ my_waitpid (second_pid, &status, 0);
+ }
+ }
+ else
+ warning ("linux_test_for_tracefork: unexpected result from waitpid "
+ "(%d, status 0x%x)", ret, status);
+
+ do
+ {
+ ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
+ if (ret != 0)
+ warning ("linux_test_for_tracefork: failed to kill child");
+ my_waitpid (child_pid, &status, 0);
+ }
+ while (WIFSTOPPED (status));
+
+ free (stack);
+}
+
+
+static void
+linux_look_up_symbols (void)
+{
+#ifdef USE_THREAD_DB
+ if (thread_db_active)
+ return;
+
+ thread_db_active = thread_db_init (!linux_supports_tracefork_flag);
+#endif
+}
+
+static void
+linux_request_interrupt (void)
+{
+ extern unsigned long signal_pid;
+
+ if (cont_thread != 0 && cont_thread != -1)
+ {
+ struct process_info *process;
+
+ process = get_thread_process (current_inferior);
+ kill_lwp (process->lwpid, SIGINT);
+ }
+ else
+ kill_lwp (signal_pid, SIGINT);
+}
+
+/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
+ to debugger memory starting at MYADDR. */
+
+static int
+linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len)
+{
+ char filename[PATH_MAX];
+ int fd, n;
+
+ snprintf (filename, sizeof filename, "/proc/%ld/auxv", inferior_pid);
+
+ fd = open (filename, O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ if (offset != (CORE_ADDR) 0
+ && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
+ n = -1;
+ else
+ n = read (fd, myaddr, len);
+
+ close (fd);
+
+ return n;
+}
+
+/* These watchpoint related wrapper functions simply pass on the function call
+ if the target has registered a corresponding function. */
+
+static int
+linux_insert_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ if (the_low_target.insert_watchpoint != NULL)
+ return the_low_target.insert_watchpoint (type, addr, len);
+ else
+ /* Unsupported (see target.h). */
+ return 1;
+}
+
+static int
+linux_remove_watchpoint (char type, CORE_ADDR addr, int len)
+{
+ if (the_low_target.remove_watchpoint != NULL)
+ return the_low_target.remove_watchpoint (type, addr, len);
+ else
+ /* Unsupported (see target.h). */
+ return 1;
+}
+
+static int
+linux_stopped_by_watchpoint (void)
+{
+ if (the_low_target.stopped_by_watchpoint != NULL)
+ return the_low_target.stopped_by_watchpoint ();
+ else
+ return 0;
+}
+
+static CORE_ADDR
+linux_stopped_data_address (void)
+{
+ if (the_low_target.stopped_data_address != NULL)
+ return the_low_target.stopped_data_address ();
+ else
+ return 0;
+}
+
+#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+#if defined(__mcoldfire__)
+/* These should really be defined in the kernel's ptrace.h header. */
+#define PT_TEXT_ADDR 49*4
+#define PT_DATA_ADDR 50*4
+#define PT_TEXT_END_ADDR 51*4
+#endif
+
+/* Under uClinux, programs are loaded at non-zero offsets, which we need
+ to tell gdb about. */
+
+static int
+linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
+{
+#if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
+ unsigned long text, text_end, data;
+ int pid = get_thread_process (current_inferior)->head.id;
+
+ errno = 0;
+
+ text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0);
+ text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0);
+ data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0);
+
+ if (errno == 0)
+ {
+ /* Both text and data offsets produced at compile-time (and so
+ used by gdb) are relative to the beginning of the program,
+ with the data segment immediately following the text segment.
+ However, the actual runtime layout in memory may put the data
+ somewhere else, so when we send gdb a data base-address, we
+ use the real data base address and subtract the compile-time
+ data base-address from it (which is just the length of the
+ text segment). BSS immediately follows data in both
+ cases. */
+ *text_p = text;
+ *data_p = data - (text_end - text);
+
+ return 1;
+ }
+#endif
+ return 0;
+}
+#endif
+
+static const char *
+linux_arch_string (void)
+{
+ return the_low_target.arch_string;
+}
+
static struct target_ops linux_target_ops = {
linux_create_inferior,
linux_attach,
linux_kill,
+ linux_detach,
+ linux_join,
linux_thread_alive,
linux_resume,
linux_wait,
linux_store_registers,
linux_read_memory,
linux_write_memory,
+ linux_look_up_symbols,
+ linux_request_interrupt,
+ linux_read_auxv,
+ linux_insert_watchpoint,
+ linux_remove_watchpoint,
+ linux_stopped_by_watchpoint,
+ linux_stopped_data_address,
+#if defined(__UCLIBC__) && defined(HAS_NOMMU)
+ linux_read_offsets,
+#else
+ NULL,
+#endif
+#ifdef USE_THREAD_DB
+ thread_db_get_tls_address,
+#else
+ NULL,
+#endif
+ linux_arch_string,
};
+static void
+linux_init_signals ()
+{
+ /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
+ to find what the cancel signal actually is. */
+ signal (__SIGRTMIN+1, SIG_IGN);
+}
+
void
initialize_low (void)
{
+ thread_db_active = 0;
set_target_ops (&linux_target_ops);
+ set_breakpoint_data (the_low_target.breakpoint,
+ the_low_target.breakpoint_len);
init_registers ();
+ linux_init_signals ();
+ linux_test_for_tracefork ();
}
projects / deliverable / binutils-gdb.git / blobdiff