mirror of
https://github.com/varun-r-mallya/sysprof.git
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move source around in preparation to land sysprof2
This commit is contained in:
Christian Hergert
215
lib/signal-handler.c
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215
lib/signal-handler.c
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- */
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/* Sysprof -- Sampling, systemwide CPU profiler
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* Copyright (C) 2005 Søren Sandmann (sandmann@daimi.au.dk)
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <signal.h>
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#include <unistd.h>
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#include <string.h>
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#include "watch.h"
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#include "signal-handler.h"
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typedef struct SignalWatch SignalWatch;
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struct SignalWatch
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{
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int signo;
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SignalFunc handler;
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gpointer user_data;
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struct sigaction old_action;
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SignalWatch * next;
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};
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static int read_end = -1;
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static int write_end = -1;
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static SignalWatch *signal_watches = NULL;
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static SignalWatch *
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lookup_signal_watch (int signo)
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{
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SignalWatch *w;
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for (w = signal_watches; w != NULL; w = w->next)
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{
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if (w->signo == signo)
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return w;
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}
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return NULL;
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}
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static void
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remove_signal_watch (SignalWatch *watch)
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{
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SignalWatch *prev, *w;
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g_return_if_fail (watch != NULL);
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prev = NULL;
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for (w = signal_watches; w != NULL; w = w->next)
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{
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if (w == watch)
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{
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if (prev)
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prev->next = w->next;
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else
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signal_watches = w->next;
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break;
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}
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prev = w;
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}
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}
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static void
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signal_handler (int signo,
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siginfo_t *info,
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void *data)
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{
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/* FIXME: I suppose we should handle short
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* and non-successful writes ...
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*
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* And also, there is a deadlock if so many signals arrive that
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* write() blocks. Then we will be stuck right here, and the
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* main loop will never run. Kinda hard to fix without dropping
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* signals ...
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*
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*/
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write (write_end, &signo, sizeof (int));
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}
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static void
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on_read (gpointer data)
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{
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SignalWatch *watch;
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int signo;
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/* FIXME: handle short read I suppose */
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read (read_end, &signo, sizeof (int));
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watch = lookup_signal_watch (signo);
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if (watch)
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watch->handler (signo, watch->user_data);
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}
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static gboolean
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create_pipe (int *read_end,
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int *write_end,
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GError **err)
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{
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int p[2];
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if (pipe (p) < 0)
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{
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/* FIXME - create an error */
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return FALSE;
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}
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/* FIXME: We should probably make the fd's non-blocking */
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if (read_end)
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*read_end = p[0];
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if (write_end)
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*write_end = p[1];
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return TRUE;
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}
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static gboolean
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install_signal_handler (int signo,
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struct sigaction *old_action,
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GError **err)
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{
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struct sigaction action;
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memset (&action, 0, sizeof (action));
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action.sa_sigaction = signal_handler;
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sigemptyset (&action.sa_mask);
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action.sa_flags = SA_SIGINFO;
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if (sigaction (signo, &action, old_action) < 0)
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{
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/* FIXME - create an error */
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return TRUE;
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}
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return TRUE;
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}
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static void
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signal_watch_free (SignalWatch *watch)
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{
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remove_signal_watch (watch);
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g_free (watch);
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}
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gboolean
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signal_set_handler (int signo,
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SignalFunc handler,
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gpointer data,
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GError **err)
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{
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SignalWatch *watch;
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g_return_val_if_fail (lookup_signal_watch (signo) == NULL, FALSE);
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if (read_end == -1)
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{
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if (!create_pipe (&read_end, &write_end, err))
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return FALSE;
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fd_add_watch (read_end, NULL);
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fd_set_read_callback (read_end, on_read);
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}
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watch = g_new0 (SignalWatch, 1);
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watch->signo = signo;
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watch->handler = handler;
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watch->user_data = data;
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watch->next = signal_watches;
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signal_watches = watch;
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if (!install_signal_handler (signo, &watch->old_action, err))
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{
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signal_watch_free (watch);
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return FALSE;
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}
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return TRUE;
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}
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void
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signal_unset_handler (int signo)
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{
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SignalWatch *watch;
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watch = lookup_signal_watch (signo);
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g_return_if_fail (watch != NULL);
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sigaction (signo, &watch->old_action, NULL);
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signal_watch_free (watch);
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}
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