move signal handlers to sighandler.[ch]

Signals are special because they run asynchronously, making them
non-trivial to handle correctly.  Move the handlers a separate file to
offset them from the normal code and make them easier to separate into
individual functions without further cluttering pacman.c

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>
This commit is contained in:
Andrew Gregory 2015-11-30 12:36:30 -05:00 committed by Allan McRae
parent 220a3ce2b8
commit 4d2317dafb
4 changed files with 122 additions and 58 deletions

View File

@ -40,6 +40,7 @@ pacman_SOURCES = \
pacman.h pacman.c \
query.c \
remove.c \
sighandler.h sighandler.c \
sync.c \
callback.h callback.c \
upgrade.c \

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@ -30,7 +30,6 @@
#include <limits.h>
#include <getopt.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/utsname.h> /* uname */
@ -45,6 +44,7 @@
#include "pacman.h"
#include "util.h"
#include "conf.h"
#include "sighandler.h"
/* list of targets specified on command line */
static alpm_list_t *pm_targets;
@ -294,51 +294,6 @@ static void cleanup(int ret)
exit(ret);
}
/** Write function that correctly handles EINTR.
*/
static ssize_t xwrite(int fd, const void *buf, size_t count)
{
ssize_t ret;
do {
ret = write(fd, buf, count);
} while(ret == -1 && errno == EINTR);
return ret;
}
/** Catches thrown signals. Performs necessary cleanup to ensure database is
* in a consistent state.
* @param signum the thrown signal
*/
static void handler(int signum)
{
if(signum == SIGSEGV) {
const char msg[] = "\nerror: segmentation fault\n"
"Please submit a full bug report with --debug if appropriate.\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
exit(signum);
} else if(signum == SIGINT || signum == SIGHUP) {
if(signum == SIGINT) {
const char msg[] = "\nInterrupt signal received\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
} else {
const char msg[] = "\nHangup signal received\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
}
if(alpm_trans_interrupt(config->handle) == 0) {
/* a transaction is being interrupted, don't exit pacman yet. */
return;
}
} else if(signum == SIGWINCH) {
columns_cache_reset();
return;
}
/* SIGINT/SIGHUP: no committing transaction, release it now and then exit pacman */
alpm_unlock(config->handle);
/* output a newline to be sure we clear any line we may be on */
xwrite(STDOUT_FILENO, "\n", 1);
_Exit(128 + signum);
}
static void invalid_opt(int used, const char *opt1, const char *opt2)
{
if(used) {
@ -1134,20 +1089,9 @@ int main(int argc, char *argv[])
{
int ret = 0;
size_t i;
struct sigaction new_action;
const int signals[] = { SIGHUP, SIGINT, SIGSEGV, SIGWINCH };
uid_t myuid = getuid();
/* Set signal handlers */
/* Set up the structure to specify the new action. */
new_action.sa_handler = handler;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = SA_RESTART;
/* assign our handler to any signals we care about */
for(i = 0; i < ARRAYSIZE(signals); i++) {
sigaction(signals[i], &new_action, NULL);
}
install_signal_handlers();
/* i18n init */
#if defined(ENABLE_NLS)

92
src/pacman/sighandler.c Normal file
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@ -0,0 +1,92 @@
/*
* sighandler.c
*
* Copyright (c) 2015 Pacman Development Team <pacman-dev@archlinux.org>
*
* 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
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <alpm.h>
#include "conf.h"
#include "sighandler.h"
#include "util.h"
/** Write function that correctly handles EINTR.
*/
static ssize_t xwrite(int fd, const void *buf, size_t count)
{
ssize_t ret;
do {
ret = write(fd, buf, count);
} while(ret == -1 && errno == EINTR);
return ret;
}
/** Catches thrown signals. Performs necessary cleanup to ensure database is
* in a consistent state.
* @param signum the thrown signal
*/
static void handler(int signum)
{
if(signum == SIGSEGV) {
const char msg[] = "\nerror: segmentation fault\n"
"Please submit a full bug report with --debug if appropriate.\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
exit(signum);
} else if(signum == SIGINT || signum == SIGHUP) {
if(signum == SIGINT) {
const char msg[] = "\nInterrupt signal received\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
} else {
const char msg[] = "\nHangup signal received\n";
xwrite(STDERR_FILENO, msg, ARRAYSIZE(msg) - 1);
}
if(alpm_trans_interrupt(config->handle) == 0) {
/* a transaction is being interrupted, don't exit pacman yet. */
return;
}
} else if(signum == SIGWINCH) {
columns_cache_reset();
return;
}
/* SIGINT/SIGHUP: no committing transaction, release it now and then exit pacman */
alpm_unlock(config->handle);
/* output a newline to be sure we clear any line we may be on */
xwrite(STDOUT_FILENO, "\n", 1);
_Exit(128 + signum);
}
void install_signal_handlers(void)
{
struct sigaction new_action;
const int signals[] = { SIGHUP, SIGINT, SIGSEGV, SIGWINCH };
size_t i;
/* Set signal handlers */
/* Set up the structure to specify the new action. */
new_action.sa_handler = handler;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = SA_RESTART;
/* assign our handler to any signals we care about */
for(i = 0; i < ARRAYSIZE(signals); i++) {
sigaction(signals[i], &new_action, NULL);
}
}
/* vim: set noet: */

27
src/pacman/sighandler.h Normal file
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@ -0,0 +1,27 @@
/*
* sighandler.h
*
* Copyright (c) 2015 Pacman Development Team <pacman-dev@archlinux.org>
*
* 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
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* 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, see <http://www.gnu.org/licenses/>.
*/
#ifndef _PM_SIGHANDLER_H
#define _PM_SIGHANDLER_H
void install_signal_handlers(void);
#endif /* _PM_SIGHANDLER_H */
/* vim: set noet: */