##// END OF EJS Templates
update: show the commit to which we updated in case of multiple heads (BC)...
update: show the commit to which we updated in case of multiple heads (BC) Currently when we have multiple heads on the same branch, update tells us that there some more heads for the current branch but does not tells us the head to which the repository has been updated to. It makes more sense showing the head we updated to and then telling there are some more heads.

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procutil.c
237 lines | 5.6 KiB | text/x-c | CLexer
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 /*
* Utilities about process handling - signal and subprocess (ex. pager)
*
* Copyright (c) 2011 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.
*/
Jun Wu
chg: add procutil.h...
r30693 #include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
#include "procutil.h"
#include "util.h"
Jun Wu
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r30689 static pid_t pagerpid = 0;
static pid_t peerpgid = 0;
static pid_t peerpid = 0;
static void forwardsignal(int sig)
{
assert(peerpid > 0);
if (kill(peerpid, sig) < 0)
abortmsgerrno("cannot kill %d", peerpid);
debugmsg("forward signal %d", sig);
}
static void forwardsignaltogroup(int sig)
{
/* prefer kill(-pgid, sig), fallback to pid if pgid is invalid */
pid_t killpid = peerpgid > 1 ? -peerpgid : peerpid;
if (kill(killpid, sig) < 0)
abortmsgerrno("cannot kill %d", killpid);
debugmsg("forward signal %d to %d", sig, killpid);
}
static void handlestopsignal(int sig)
{
sigset_t unblockset, oldset;
struct sigaction sa, oldsa;
if (sigemptyset(&unblockset) < 0)
goto error;
if (sigaddset(&unblockset, sig) < 0)
goto error;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
forwardsignal(sig);
if (raise(sig) < 0) /* resend to self */
goto error;
if (sigaction(sig, &sa, &oldsa) < 0)
goto error;
if (sigprocmask(SIG_UNBLOCK, &unblockset, &oldset) < 0)
goto error;
/* resent signal will be handled before sigprocmask() returns */
if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
goto error;
if (sigaction(sig, &oldsa, NULL) < 0)
goto error;
return;
error:
abortmsgerrno("failed to handle stop signal");
}
static void handlechildsignal(int sig UNUSED_)
{
if (peerpid == 0 || pagerpid == 0)
return;
/* if pager exits, notify the server with SIGPIPE immediately.
* otherwise the server won't get SIGPIPE if it does not write
* anything. (issue5278) */
if (waitpid(pagerpid, NULL, WNOHANG) == pagerpid)
kill(peerpid, SIGPIPE);
}
Jun Wu
chg: add procutil.h...
r30693 void setupsignalhandler(pid_t pid, pid_t pgid)
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 {
if (pid <= 0)
return;
peerpid = pid;
peerpgid = (pgid <= 1 ? 0 : pgid);
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
Jun Wu
chg: document why we send SIGHUP and SIGINT to process group...
r31229
/* 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 */
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 sa.sa_handler = forwardsignaltogroup;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
if (sigaction(SIGHUP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGINT, &sa, NULL) < 0)
goto error;
/* 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)
goto error;
/* notify the worker about window resize events */
sa.sa_flags = SA_RESTART;
if (sigaction(SIGWINCH, &sa, NULL) < 0)
goto error;
Jun Wu
chg: forward user-defined signals...
r31230 /* forward user-defined signals */
if (sigaction(SIGUSR1, &sa, NULL) < 0)
goto error;
if (sigaction(SIGUSR2, &sa, NULL) < 0)
goto error;
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 /* propagate job control requests to worker */
sa.sa_handler = forwardsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCONT, &sa, NULL) < 0)
goto error;
sa.sa_handler = handlestopsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGTSTP, &sa, NULL) < 0)
goto error;
/* get notified when pager exits */
sa.sa_handler = handlechildsignal;
sa.sa_flags = SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) < 0)
goto error;
return;
error:
abortmsgerrno("failed to set up signal handlers");
}
Jun Wu
chg: add procutil.h...
r30693 void restoresignalhandler(void)
Jun Wu
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r30689 {
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_RESTART;
if (sigemptyset(&sa.sa_mask) < 0)
goto error;
if (sigaction(SIGHUP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGTERM, &sa, NULL) < 0)
goto error;
if (sigaction(SIGWINCH, &sa, NULL) < 0)
goto error;
if (sigaction(SIGCONT, &sa, NULL) < 0)
goto error;
if (sigaction(SIGTSTP, &sa, NULL) < 0)
goto error;
if (sigaction(SIGCHLD, &sa, NULL) < 0)
goto error;
/* ignore Ctrl+C while shutting down to make pager exits cleanly */
sa.sa_handler = SIG_IGN;
if (sigaction(SIGINT, &sa, NULL) < 0)
goto error;
peerpid = 0;
return;
error:
abortmsgerrno("failed to restore signal handlers");
}
/* This implementation is based on hgext/pager.py (post 369741ef7253)
* Return 0 if pager is not started, or pid of the pager */
Jun Wu
chg: respect environment variables for pager...
r31941 pid_t setuppager(const char *pagercmd, const char *envp[])
Jun Wu
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r30689 {
Jun Wu
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r30692 assert(pagerpid == 0);
Jun Wu
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r30689 if (!pagercmd)
return 0;
int pipefds[2];
if (pipe(pipefds) < 0)
return 0;
pid_t pid = fork();
if (pid < 0)
goto error;
if (pid > 0) {
close(pipefds[0]);
if (dup2(pipefds[1], fileno(stdout)) < 0)
goto error;
if (isatty(fileno(stderr))) {
if (dup2(pipefds[1], fileno(stderr)) < 0)
goto error;
}
close(pipefds[1]);
Jun Wu
chg: let procutil maintain its own pagerpid...
r30692 pagerpid = pid;
Jun Wu
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r30689 return pid;
} else {
dup2(pipefds[0], fileno(stdin));
close(pipefds[0]);
close(pipefds[1]);
Jun Wu
chg: respect environment variables for pager...
r31941 int r = execle("/bin/sh", "/bin/sh", "-c", pagercmd, NULL,
envp);
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 if (r < 0) {
abortmsgerrno("cannot start pager '%s'", pagercmd);
}
return 0;
}
error:
close(pipefds[0]);
close(pipefds[1]);
abortmsgerrno("failed to prepare pager");
return 0;
}
Jun Wu
chg: add procutil.h...
r30693 void waitpager(void)
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 {
Jun Wu
chg: let procutil maintain its own pagerpid...
r30692 if (pagerpid == 0)
return;
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 /* close output streams to notify the pager its input ends */
fclose(stdout);
fclose(stderr);
while (1) {
Jun Wu
chg: let procutil maintain its own pagerpid...
r30692 pid_t ret = waitpid(pagerpid, NULL, 0);
Jun Wu
chg: move signal and pager handling to a separate file...
r30689 if (ret == -1 && errno == EINTR)
continue;
break;
}
}