/*
- * Copyright (C) 2004-2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2004-2011 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file signal.c signal handling functions */
+/** \file signal.c Signal handling functions. */
#include <signal.h>
#include <sys/types.h>
-#include <dirent.h>
#include "para.h"
#include "error.h"
goto err_out;
return signal_pipe[0];
err_out:
- PARA_EMERG_LOG("%s\n", PARA_STRERROR(-ret));
+ PARA_EMERG_LOG("%s\n", para_strerror(-ret));
exit(EXIT_FAILURE);
}
*/
static void generic_signal_handler(int s)
{
- write(signal_pipe[1], &s, sizeof(int));
- //fprintf(stderr, "got sig %i, write returned %d\n", s, ret);
+ ssize_t ret = write(signal_pipe[1], &s, sizeof(int));
+
+ if (ret == sizeof(int))
+ return;
+ if (ret < 0)
+ PARA_EMERG_LOG("%s\n", strerror(errno));
+ else
+ PARA_EMERG_LOG("short write to signal pipe\n");
+ exit(EXIT_FAILURE);
}
/**
* one otherwise. If and only if the function returns one, the content of \a
* pid is meaningful.
*
- * \sa waitpid(2)
+ * \sa waitpid(2).
*/
int para_reap_child(pid_t *pid)
{
if (*pid < 0)
return -ERRNO_TO_PARA_ERROR(errno);
if (WIFEXITED(status))
- PARA_DEBUG_LOG("child %i exited. Exit status: %i\n", *pid,
+ PARA_DEBUG_LOG("child %i exited. Exit status: %i\n", (int)*pid,
WEXITSTATUS(status));
else if (WIFSIGNALED(status))
- PARA_DEBUG_LOG("child %i was killed by signal %i\n", *pid,
+ PARA_DEBUG_LOG("child %i was killed by signal %i\n", (int)*pid,
WTERMSIG(status));
else
- PARA_WARNING_LOG("child %i terminated abormally\n", *pid);
+ PARA_WARNING_LOG("child %i terminated abormally\n", (int)*pid);
return 1;
}
/**
- * Paraslash's zombie killer.
+ * Install the given handler for the given signal.
*
- * It just calls \p para_reap_child() until there are no more children left to
- * reap.
+ * \param sig The number of the signal to catch.
+ * \param handler to be installed, \p SIG_IGN, or \p SIG_DFL.
+ *
+ * This either succeeds or calls exit(EXIT_FAILURE).
+ *
+ * \sa sigaction(2).
*/
-void para_reap_children(void)
+void para_sigaction(int sig, void (*handler)(int))
{
- pid_t pid;
+ struct sigaction act;
- while (para_reap_child(&pid) > 0)
- ; /* nothing */
+ PARA_DEBUG_LOG("catching signal %d\n", sig);
+ act.sa_handler = handler;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ if (sig == SIGALRM) {
+ #ifdef SA_INTERRUPT /* SunOS */
+ act.sa_flags |= SA_INTERRUPT;
+ #endif
+ } else {
+ #ifdef SA_RESTART /* BSD */
+ act.sa_flags |= SA_RESTART;
+ #endif
+ }
+ if (sigaction(sig, &act, NULL) >= 0)
+ return;
+ PARA_EMERG_LOG("failed to install signal handler for signal %d\n",
+ sig);
+ exit(EXIT_FAILURE);
}
/**
- * wrapper around signal(2)
- * \param sig the number of the signal to catch
+ * Install the generic signal handler for the given signal number.
+ *
+ * \param sig The number of the signal to catch.
*
- * This installs the generic signal handler for the given signal.
- * \return This function returns 1 on success and \p -E_SIGNAL_SIG_ERR on errors.
- * \sa signal(2)
+ * \sa signal(2), sigaction(2).
*/
-int para_install_sighandler(int sig)
+void para_install_sighandler(int sig)
{
- PARA_DEBUG_LOG("catching signal %d\n", sig);
- return signal(sig, &generic_signal_handler) == SIG_ERR? -E_SIGNAL_SIG_ERR : 1;
+ para_sigaction(sig, &generic_signal_handler);
+}
+
+/**
+ * Block a signal for the caller.
+ *
+ * \param sig The signal to block.
+ *
+ * This sets the given signal in the current signal mask of the calling process
+ * to prevent this signal from delivery.
+ *
+ * \sa \ref para_unblock_signal(), sigprocmask(2), sigaddset(3).
+ */
+void para_block_signal(int sig)
+{
+ sigset_t set;
+
+ PARA_DEBUG_LOG("blocking signal %d\n", sig);
+ sigemptyset(&set);
+ sigaddset(&set, sig);
+ sigprocmask(SIG_BLOCK, &set, NULL);
}
/**
- * return number of next pending signal
+ * Unblock a signal.
+ *
+ * \param sig The signal to unblock.
*
- * This should be called if the fd for the signal pipe is ready for reading.
+ * This function removes the given signal from the current set of blocked
+ * signals.
*
- * \return On success, the number of the received signal is returned. \p
- * -E_SIGNAL_READ is returned if a read error occurred while reading the signal
- * pipe. If the read was interrupted by another signal the function returns 0.
+ * \sa \ref para_block_signal(), sigprocmask(2), sigaddset(3).
*/
-int para_next_signal(void)
+void para_unblock_signal(int sig)
{
- int s;
- ssize_t r;
+ sigset_t set;
+
+ PARA_DEBUG_LOG("unblocking signal %d\n", sig);
+ sigemptyset(&set);
+ sigaddset(&set, sig);
+ sigprocmask(SIG_UNBLOCK, &set, NULL);
+}
- if ((r = read(signal_pipe[0], &s, sizeof(s)) == sizeof(s)) > 0) {
- PARA_DEBUG_LOG("next signal: %d\n", s);
- return s;
+/**
+ * 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)
+{
+ size_t n;
+ int s, ret = read_nonblock(signal_pipe[0], &s, sizeof(s), rfds, &n);
+
+ if (ret < 0) {
+ PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+ exit(EXIT_FAILURE);
}
- return r < 0 && (errno != EAGAIN)? 0 : -E_SIGNAL_READ;
+ if (n == 0)
+ return 0;
+ assert(n == sizeof(s));
+ PARA_DEBUG_LOG("next signal: %d\n", s);
+ return s;
}
/**
- * Close the signal pipe.
+ * Close the write end of the signal pipe.
*/
void para_signal_shutdown(void)
{
projects / paraslash.git / blobdiff