-/*
- * Copyright (C) 2004-2014 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2004 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
/** \file signal.c Signal handling functions. */
#include <signal.h>
#include <sys/types.h>
+#include <regex.h>
#include "para.h"
#include "error.h"
#include "fd.h"
#include "list.h"
+#include "string.h"
#include "sched.h"
#include "signal.h"
* This function creates a pipe, the signal pipe, to deliver pending
* signals to the application (Bernstein's trick). It should be called
* during the application's startup part, followed by subsequent calls
- * to para_install_sighandler() for each signal that should be caught.
+ * to \ref para_install_sighandler() for each signal that should be caught.
*
* A generic signal handler is used for all signals simultaneously. When a
* signal arrives, the signal handler writes the number of the signal received
* to one end of the signal pipe. The application can test for pending signals
* by checking if the file descriptor of the other end of the signal pipe is
- * ready for reading, see select(2).
+ * ready for reading.
*
- * \return This function either succeeds or calls exit(2) to terminate the
- * current process. On success, the file descriptor of the read end of the
- * signal pipe is returned.
+ * \return This function either succeeds or calls exit(3) to terminate the
+ * current process. On success, a signal task structure is returned.
*/
-int para_signal_init(void)
+struct signal_task *signal_init_or_die(void)
{
+ struct signal_task *st;
int ret;
+
+ PARA_NOTICE_LOG("setting up signal handling\n");
if (pipe(signal_pipe) < 0) {
ret = -ERRNO_TO_PARA_ERROR(errno);
goto err_out;
ret = mark_fd_nonblocking(signal_pipe[1]);
if (ret < 0)
goto err_out;
- return signal_pipe[0];
+ st = zalloc(sizeof(*st));
+ st->fd = signal_pipe[0];
+ return st;
err_out:
PARA_EMERG_LOG("%s\n", para_strerror(-ret));
exit(EXIT_FAILURE);
errno = save_errno;
return;
}
- if (ret < 0)
- PARA_EMERG_LOG("%s\n", strerror(errno));
- else
- PARA_EMERG_LOG("short write to signal pipe\n");
+ /*
+ * This is a fatal error which should never happen. We must not call
+ * PARA_XXX_LOG() here because this might acquire the log mutex which
+ * is already taken by the main program if the interrupt occurs while a
+ * log message is being printed. The mutex will not be released as long
+ * as this signal handler is running, so a deadlock ensues.
+ */
exit(EXIT_FAILURE);
}
/**
* Return the number of the next pending signal.
*
- * \param rfds The fd_set containing the signal pipe.
- *
* \return On success, the number of the received signal is returned. If there
* is no signal currently pending, the function returns zero. On read errors
* from the signal pipe, the process is terminated.
*/
-int para_next_signal(fd_set *rfds)
+int para_next_signal(void)
{
size_t n;
- int s, ret = read_nonblock(signal_pipe[0], &s, sizeof(s), rfds, &n);
+ int s, ret = read_nonblock(signal_pipe[0], &s, sizeof(s), &n);
if (ret < 0) {
PARA_EMERG_LOG("%s\n", para_strerror(-ret));
}
/**
- * Close the write end of the signal pipe.
+ * Close the write end of the signal pipe, deallocate resources.
+ *
+ * \param st The pointer obtained earlier from signal_init_or_die().
*/
-void para_signal_shutdown(void)
+void signal_shutdown(struct signal_task *st)
{
close(signal_pipe[1]);
+ free(st);
}