##// END OF EJS Templates
revlog-native: introduced ABI version in capsule...
revlog-native: introduced ABI version in capsule Concerns that an inconsistency could arise between the actual contents of the capsule in revlog.c and the Rust consumer have been raised after the switch to the array of data and function pointers in f384d68d8ea8. It has been suggested that the `version` from parsers.c could be use for this. In this change, we introduce instead a separate ABI version number, which should have the following advantages: - no need to change the consuming Rust code for changes that have nothing to do with the contents of the capsule - the version number in parsers.c is not explicitely flagged as ABI. It's not obvious to me whether an ABI change that would be invisible to Python would warrant an increment The drawback is that developers now have to consider two version numbers. We expect the added cost of the check to be negligible because it occurs at instantiation of `CIndex` only, which in turn is tied to instantiation of Python objects such as `LazyAncestors` and `MixedIndex`. Frequent calls to `Cindex::new` should also probably hit the CPU branch predictor. Differential Revision: https://phab.mercurial-scm.org/D7856

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sighandlers.c
175 lines | 3.7 KiB | text/x-c | CLexer
/*
* Signal handlers for cHg
*
* Copyright 2011, 2018 Yuya Nishihara <yuya@tcha.org>
*
* This software may be used and distributed according to the terms of the
* GNU General Public License version 2 or any later version.
*/
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
static pid_t peerpgid = 0;
static pid_t peerpid = 0;
static void forwardsignal(int sig)
{
assert(peerpid > 0);
(void)kill(peerpid, sig);
}
static void forwardsignaltogroup(int sig)
{
/* prefer kill(-pgid, sig), fallback to pid if pgid is invalid */
pid_t killpid = peerpgid > 1 ? -peerpgid : peerpid;
(void)kill(killpid, sig);
}
static void handlestopsignal(int sig)
{
sigset_t unblockset, oldset;
struct sigaction sa, oldsa;
if (sigemptyset(&unblockset) < 0) {
return;
}
if (sigaddset(&unblockset, sig) < 0) {
return;
}
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0) {
return;
}
forwardsignal(sig);
if (raise(sig) < 0) { /* resend to self */
return;
}
if (sigaction(sig, &sa, &oldsa) < 0) {
return;
}
if (sigprocmask(SIG_UNBLOCK, &unblockset, &oldset) < 0) {
return;
}
/* resent signal will be handled before sigprocmask() returns */
if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0) {
return;
}
if (sigaction(sig, &oldsa, NULL) < 0) {
return;
}
}
/*
* Installs signal handlers.
*
* Returns 0 on success, -1 on error and errno is set appropriately.
* Installed handlers wouldn't be cleaned up on error.
*/
int setupsignalhandler(pid_t pid, pid_t pgid)
{
if (pid <= 0) {
errno = EINVAL;
return -1;
}
peerpid = pid;
peerpgid = (pgid <= 1 ? 0 : pgid);
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
/* deadly signals meant to be sent to a process group:
* - SIGHUP: usually generated by the kernel, when termination of a
* process causes that process group to become orphaned
* - SIGINT: usually generated by the terminal */
sa.sa_handler = forwardsignaltogroup;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0) {
return -1;
}
if (sigaction(SIGHUP, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGINT, &sa, NULL) < 0) {
return -1;
}
/* terminate frontend by double SIGTERM in case of server freeze */
sa.sa_handler = forwardsignal;
sa.sa_flags |= SA_RESETHAND;
if (sigaction(SIGTERM, &sa, NULL) < 0) {
return -1;
}
/* notify the worker about window resize events */
sa.sa_flags = SA_RESTART;
if (sigaction(SIGWINCH, &sa, NULL) < 0) {
return -1;
}
/* forward user-defined signals */
if (sigaction(SIGUSR1, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGUSR2, &sa, NULL) < 0) {
return -1;
}
/* propagate job control requests to worker */
sa.sa_handler = forwardsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCONT, &sa, NULL) < 0) {
return -1;
}
sa.sa_handler = handlestopsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGTSTP, &sa, NULL) < 0) {
return -1;
}
return 0;
}
/*
* Restores signal handlers to the default, and masks SIGINT.
*
* Returns 0 on success, -1 on error and errno is set appropriately.
*/
int restoresignalhandler(void)
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0) {
return -1;
}
if (sigaction(SIGHUP, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGTERM, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGWINCH, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGCONT, &sa, NULL) < 0) {
return -1;
}
if (sigaction(SIGTSTP, &sa, NULL) < 0) {
return -1;
}
/* ignore Ctrl+C while shutting down to make pager exits cleanly */
sa.sa_handler = SIG_IGN;
if (sigaction(SIGINT, &sa, NULL) < 0) {
return -1;
}
peerpid = 0;
return 0;
}