/* Low level interface to ptrace, for the remote server for GDB.
- Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002
+ Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+ 2006
Free Software Foundation, Inc.
This file is part of GDB.
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. */
+ Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
#include "server.h"
#include "linux-low.h"
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
+#include <errno.h>
+#include <sys/syscall.h>
-static CORE_ADDR linux_bp_reinsert;
+/* ``all_threads'' is keyed by the LWP ID - it should be the thread ID instead,
+ however. This requires changing the ID in place when we go from !using_threads
+ to using_threads, immediately.
-static void linux_resume (int step, int signal);
+ ``all_processes'' is keyed by the process ID - which on Linux is (presently)
+ the same as the LWP ID. */
+
+struct inferior_list all_processes;
+
+/* FIXME this is a bit of a hack, and could be removed. */
+int stopping_threads;
+
+/* FIXME make into a target method? */
+int using_threads;
+
+static void linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal);
+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);
+
+struct pending_signals
+{
+ int signal;
+ struct pending_signals *prev;
+};
#define PTRACE_ARG3_TYPE long
#define PTRACE_XFER_TYPE long
static int use_regsets_p = 1;
#endif
-extern int errno;
+int debug_threads = 0;
+
+#define pid_of(proc) ((proc)->head.id)
+
+/* FIXME: Delete eventually. */
+#define inferior_pid (pid_of (get_thread_process (current_inferior)))
+
+/* 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) ();
-static int inferior_pid;
+ if (get_thread_process (current_inferior)->stepping)
+ return stop_pc;
+ else
+ return stop_pc - the_low_target.decr_pc_after_break;
+}
-struct inferior_linux_data
+static void *
+add_process (unsigned long pid)
{
- int pid;
-};
+ struct process_info *process;
+
+ process = (struct process_info *) malloc (sizeof (*process));
+ memset (process, 0, sizeof (*process));
+
+ process->head.id = pid;
+
+ /* Default to tid == lwpid == pid. */
+ process->tid = 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)
{
- struct inferior_linux_data *tdata;
+ void *new_process;
int pid;
pid = fork ();
{
ptrace (PTRACE_TRACEME, 0, 0, 0);
+ signal (__SIGRTMIN + 1, SIG_DFL);
+
+ setpgid (0, 0);
+
execv (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program,
_exit (0177);
}
- add_inferior (pid);
- tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata));
- tdata->pid = pid;
- set_inferior_target_data (current_inferior, tdata);
+ new_process = add_process (pid);
+ add_thread (pid, new_process, pid);
- /* FIXME remove */
- inferior_pid = pid;
- return 0;
+ return pid;
}
/* Attach to an inferior process. */
-static int
-linux_attach (int pid)
+void
+linux_attach_lwp (unsigned long pid, unsigned long tid)
{
- struct inferior_linux_data *tdata;
+ struct process_info *new_process;
if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
{
- fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid,
- errno < sys_nerr ? sys_errlist[errno] : "unknown error",
- errno);
+ fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
+ strerror (errno), errno);
fflush (stderr);
- _exit (0177);
+
+ /* If we fail to attach to an LWP, just return. */
+ if (!using_threads)
+ _exit (0177);
+ return;
}
- add_inferior (pid);
- tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata));
- tdata->pid = pid;
- set_inferior_target_data (current_inferior, tdata);
+ new_process = (struct process_info *) add_process (pid);
+ add_thread (tid, new_process, pid);
+
+ /* 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, pid);
+
+ /* Don't ignore the initial SIGSTOP if we just attached to this process. */
+ 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 (void)
+linux_kill_one_process (struct inferior_list_entry *entry)
{
- if (inferior_pid == 0)
+ 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;
- ptrace (PTRACE_KILL, inferior_pid, 0, 0);
- wait (0);
- clear_inferiors ();
+
+ 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 = get_thread_process (thread);
+ int wstat;
+
+ 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. */
+ 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);
+
+ ptrace (PTRACE_DETACH, pid_of (process), 0, 0);
+}
+
+static void
+linux_detach (void)
+{
+ for_each_inferior (&all_threads, linux_detach_one_process);
}
/* Return nonzero if the given thread is still alive. */
static int
-linux_thread_alive (int pid)
+linux_thread_alive (unsigned long tid)
+{
+ if (find_inferior_id (&all_threads, tid) != 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.\n");
+
+ 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.\n");
+
+ 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
-linux_wait_for_one_inferior (struct inferior_info *child)
+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);
+ return 0;
+ }
+
+ return process->status_pending_p;
+}
+
+static void
+linux_wait_for_process (struct process_info **childp, int *wstatp)
{
- struct inferior_linux_data *child_data = inferior_target_data (child);
- int pid, wstat;
+ int ret;
+ int to_wait_for = -1;
+
+ if (*childp != NULL)
+ to_wait_for = (*childp)->lwpid;
while (1)
{
- pid = waitpid (child_data->pid, &wstat, 0);
+ 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);
+
+ (*childp)->stopped = 1;
+ (*childp)->pending_is_breakpoint = 0;
+
+ if (debug_threads
+ && WIFSTOPPED (*wstatp))
+ {
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, (*childp)->tid);
+ /* For testing only; i386_stop_pc prints out a diagnostic. */
+ if (the_low_target.get_pc != NULL)
+ get_stop_pc ();
+ }
+}
- if (pid != child_data->pid)
- perror_with_name ("wait");
+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 this target supports breakpoints, see if we hit one. */
- if (the_low_target.stop_pc != NULL
- && WIFSTOPPED (wstat)
- && WSTOPSIG (wstat) == SIGTRAP)
+ if (event_child != NULL)
+ {
+ if (event_child->status_pending_p)
{
- CORE_ADDR stop_pc;
+ 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");
- if (linux_bp_reinsert != 0)
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, event_child->tid);
+
+ if (using_threads)
+ {
+ /* Check for thread exit. */
+ if (! WIFSTOPPED (wstat))
{
- reinsert_breakpoint (linux_bp_reinsert);
- linux_bp_reinsert = 0;
- linux_resume (0, 0);
+ if (debug_threads)
+ fprintf (stderr, "Thread %ld (LWP %ld) exiting\n",
+ event_child->tid, event_child->head.id);
+
+ /* If the last thread is exiting, just return. */
+ if (all_threads.head == all_threads.tail)
+ return wstat;
+
+ dead_thread_notify (event_child->tid);
+
+ 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;
}
- fetch_inferior_registers (0);
- stop_pc = (*the_low_target.stop_pc) ();
+ 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);
+ continue;
+ }
- if (check_breakpoints (stop_pc) != 0)
+ /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
+ thread library? */
+ if (WIFSTOPPED (wstat)
+ && (WSTOPSIG (wstat) == __SIGRTMIN
+ || WSTOPSIG (wstat) == __SIGRTMIN + 1))
{
- if (the_low_target.set_pc != NULL)
- (*the_low_target.set_pc) (stop_pc);
+ if (debug_threads)
+ fprintf (stderr, "Ignored signal %d for %ld (LWP %ld).\n",
+ WSTOPSIG (wstat), event_child->tid,
+ event_child->head.id);
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping,
+ WSTOPSIG (wstat));
+ continue;
+ }
+ }
- if (the_low_target.breakpoint_reinsert_addr == NULL)
- {
- linux_bp_reinsert = stop_pc;
- uninsert_breakpoint (stop_pc);
- linux_resume (1, 0);
- }
- else
- {
- reinsert_breakpoint_by_bp
- (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
- linux_resume (0, 0);
- }
+ /* If this event was not handled above, and is not a SIGTRAP, report
+ it. */
+ if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP)
+ return wstat;
- continue;
+ /* 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);
+ 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);
}
+ else
+ {
+ reinsert_breakpoint_by_bp
+ (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
+ linux_resume_one_process (&event_child->head, 0, 0);
+ }
+
+ 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 */
+/* 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 ();
- w = linux_wait_for_one_inferior (current_inferior);
+ unblock_async_io ();
+ w = linux_wait_for_event (child);
+ stop_all_processes ();
disable_async_io ();
- if (WIFEXITED (w))
+ /* 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)
{
- fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
- *status = 'W';
- clear_inferiors ();
- return ((unsigned char) WEXITSTATUS (w));
+ 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 ((unsigned char) 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 ((unsigned char) WTERMSIG (w));
+ }
}
- else if (!WIFSTOPPED (w))
+ else
{
- fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
- clear_inferiors ();
- *status = 'X';
- return ((unsigned char) WTERMSIG (w));
+ if (!WIFSTOPPED (w))
+ goto retry;
}
- fetch_inferior_registers (0);
-
*status = 'T';
return ((unsigned char) 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)
+ {
+ 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);
+ process->sigstop_sent = 1;
+}
+
+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->tid);
+ 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, "Stopped with non-sigstop signal\n");
+ process->status_pending_p = 1;
+ process->status_pending = wstat;
+ process->stop_expected = 1;
+ }
+
+ if (linux_thread_alive (saved_tid))
+ current_inferior = saved_inferior;
+ else
+ {
+ if (debug_threads)
+ fprintf (stderr, "Previously current thread died.\n");
+
+ /* Set a valid thread as current. */
+ set_desired_inferior (0);
+ }
+}
+
+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;
+}
+
/* 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 (int step, int signal)
+linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal)
{
+ struct process_info *process = (struct process_info *) entry;
+ struct thread_info *saved_inferior;
+
+ if (process->stopped == 0)
+ return;
+
+ /* 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))
+ {
+ struct pending_signals *p_sig;
+ p_sig = malloc (sizeof (*p_sig));
+ p_sig->prev = process->pending_signals;
+ p_sig->signal = signal;
+ process->pending_signals = p_sig;
+ }
+
+ if (process->status_pending_p && !check_removed_breakpoint (process))
+ return;
+
+ 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;
+ }
+
+ check_removed_breakpoint (process);
+
+ if (debug_threads && the_low_target.get_pc != NULL)
+ {
+ fprintf (stderr, " ");
+ (long) (*the_low_target.get_pc) ();
+ }
+
+ /* If we have pending signals, consume one unless we are trying to reinsert
+ a breakpoint. */
+ if (process->pending_signals != NULL && process->bp_reinsert == 0)
+ {
+ struct pending_signals **p_sig;
+
+ p_sig = &process->pending_signals;
+ while ((*p_sig)->prev != NULL)
+ p_sig = &(*p_sig)->prev;
+
+ signal = (*p_sig)->signal;
+ free (*p_sig);
+ *p_sig = NULL;
+ }
+
+ regcache_invalidate_one ((struct inferior_list_entry *)
+ get_process_thread (process));
errno = 0;
- ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
+ 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");
}
+static struct thread_resume *resume_ptr;
-#ifdef HAVE_LINUX_USRREGS
+/* 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_set_resume_request (struct inferior_list_entry *entry)
+{
+ 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];
+}
+
+/* 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)
+{
+ 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;
-#define REGISTER_RAW_SIZE(regno) register_size((regno))
+ 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);
+
+ process->resume = NULL;
+}
+
+/* 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 void
+linux_queue_one_thread (struct inferior_list_entry *entry)
+{
+ struct process_info *process;
+ struct thread_info *thread;
+
+ thread = (struct thread_info *) entry;
+ process = get_thread_process (thread);
+
+ if (process->resume->leave_stopped)
+ return;
+
+ /* If we have a new signal, enqueue the signal. */
+ if (process->resume->sig != 0)
+ {
+ struct pending_signals *p_sig;
+ p_sig = malloc (sizeof (*p_sig));
+ p_sig->prev = process->pending_signals;
+ p_sig->signal = process->resume->sig;
+ process->pending_signals = p_sig;
+ }
+
+ process->resume = NULL;
+}
+
+/* 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 (struct thread_resume *resume_info)
+{
+ int pending_flag;
+
+ /* Yes, the use of a global here is rather ugly. */
+ resume_ptr = resume_info;
+
+ 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);
+ }
+}
+
+#ifdef HAVE_LINUX_USRREGS
int
register_addr (int regnum)
error ("Invalid register number %d.", regnum);
addr = the_low_target.regmap[regnum];
- if (addr == -1)
- addr = 0;
return addr;
}
fetch_register (int regno)
{
CORE_ADDR regaddr;
- register int i;
+ int i, size;
+ char *buf;
if (regno >= the_low_target.num_regs)
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_store_inferior_registers (int regno)
{
CORE_ADDR regaddr;
- int i;
+ int i, size;
+ char *buf;
if (regno >= 0)
{
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)
{
if ((*the_low_target.cannot_store_register) (regno) == 0)
return;
}
}
- regaddr += sizeof (int);
+ regaddr += sizeof (PTRACE_XFER_TYPE);
}
}
else
for (regno = 0; regno < the_low_target.num_regs; regno++)
- store_inferior_registers (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));
/* 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, const 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,
static void
linux_look_up_symbols (void)
{
- /* Don't need to look up any symbols yet. */
+#ifdef USE_THREAD_DB
+ if (using_threads)
+ return;
+
+ using_threads = thread_db_init ();
+#endif
+}
+
+static void
+linux_send_signal (int signum)
+{
+ 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, signum);
+ }
+ else
+ kill_lwp (signal_pid, signum);
+}
+
+/* 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;
}
-\f
static struct target_ops linux_target_ops = {
linux_create_inferior,
linux_attach,
linux_kill,
+ linux_detach,
linux_thread_alive,
linux_resume,
linux_wait,
linux_read_memory,
linux_write_memory,
linux_look_up_symbols,
+ linux_send_signal,
+ linux_read_auxv,
+ linux_insert_watchpoint,
+ linux_remove_watchpoint,
+ linux_stopped_by_watchpoint,
+ linux_stopped_data_address,
};
+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)
{
+ using_threads = 0;
set_target_ops (&linux_target_ops);
set_breakpoint_data (the_low_target.breakpoint,
the_low_target.breakpoint_len);
init_registers ();
+ linux_init_signals ();
}
projects / deliverable / binutils-gdb.git / blobdiff