contrib/chg/procutil.c
author Pierre-Yves David <pierre-yves.david@octobus.net>
Sat, 10 Jun 2017 01:59:22 +0100
changeset 32794 6f775d10e83b
parent 31941 ac5527021097
child 35959 9724f54923ec
permissions -rw-r--r--
bookmarks: make sure we close the bookmark file after reading We previously lacked an explicit close of the bookmark file.
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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/*
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 * Utilities about process handling - signal and subprocess (ex. pager)
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 *
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 * Copyright (c) 2011 Yuya Nishihara <yuya@tcha.org>
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 *
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 * This software may be used and distributed according to the terms of the
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 * GNU General Public License version 2 or any later version.
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 */
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include "procutil.h"
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#include "util.h"
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static pid_t pagerpid = 0;
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static pid_t peerpgid = 0;
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static pid_t peerpid = 0;
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static void forwardsignal(int sig)
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{
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	assert(peerpid > 0);
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	if (kill(peerpid, sig) < 0)
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		abortmsgerrno("cannot kill %d", peerpid);
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	debugmsg("forward signal %d", sig);
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}
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static void forwardsignaltogroup(int sig)
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{
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	/* prefer kill(-pgid, sig), fallback to pid if pgid is invalid */
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	pid_t killpid = peerpgid > 1 ? -peerpgid : peerpid;
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	if (kill(killpid, sig) < 0)
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		abortmsgerrno("cannot kill %d", killpid);
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	debugmsg("forward signal %d to %d", sig, killpid);
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}
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static void handlestopsignal(int sig)
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{
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	sigset_t unblockset, oldset;
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	struct sigaction sa, oldsa;
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	if (sigemptyset(&unblockset) < 0)
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		goto error;
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	if (sigaddset(&unblockset, sig) < 0)
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		goto error;
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	memset(&sa, 0, sizeof(sa));
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	sa.sa_handler = SIG_DFL;
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	sa.sa_flags = SA_RESTART;
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	if (sigemptyset(&sa.sa_mask) < 0)
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		goto error;
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	forwardsignal(sig);
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	if (raise(sig) < 0)  /* resend to self */
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		goto error;
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	if (sigaction(sig, &sa, &oldsa) < 0)
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		goto error;
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	if (sigprocmask(SIG_UNBLOCK, &unblockset, &oldset) < 0)
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		goto error;
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	/* resent signal will be handled before sigprocmask() returns */
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	if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
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		goto error;
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	if (sigaction(sig, &oldsa, NULL) < 0)
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		goto error;
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	return;
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error:
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	abortmsgerrno("failed to handle stop signal");
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}
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static void handlechildsignal(int sig UNUSED_)
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{
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	if (peerpid == 0 || pagerpid == 0)
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		return;
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	/* if pager exits, notify the server with SIGPIPE immediately.
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	 * otherwise the server won't get SIGPIPE if it does not write
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	 * anything. (issue5278) */
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	if (waitpid(pagerpid, NULL, WNOHANG) == pagerpid)
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		kill(peerpid, SIGPIPE);
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}
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void setupsignalhandler(pid_t pid, pid_t pgid)
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{
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	if (pid <= 0)
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		return;
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	peerpid = pid;
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	peerpgid = (pgid <= 1 ? 0 : pgid);
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	struct sigaction sa;
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	memset(&sa, 0, sizeof(sa));
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	/* deadly signals meant to be sent to a process group:
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	 * - SIGHUP: usually generated by the kernel, when termination of a
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	 *   process causes that process group to become orphaned
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	 * - SIGINT: usually generated by the terminal */
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	sa.sa_handler = forwardsignaltogroup;
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	sa.sa_flags = SA_RESTART;
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   101
	if (sigemptyset(&sa.sa_mask) < 0)
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   102
		goto error;
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   103
	if (sigaction(SIGHUP, &sa, NULL) < 0)
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   104
		goto error;
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   105
	if (sigaction(SIGINT, &sa, NULL) < 0)
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   106
		goto error;
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   107
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   108
	/* terminate frontend by double SIGTERM in case of server freeze */
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   109
	sa.sa_handler = forwardsignal;
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	sa.sa_flags |= SA_RESETHAND;
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   111
	if (sigaction(SIGTERM, &sa, NULL) < 0)
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   112
		goto error;
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   113
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   114
	/* notify the worker about window resize events */
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   115
	sa.sa_flags = SA_RESTART;
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   116
	if (sigaction(SIGWINCH, &sa, NULL) < 0)
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   117
		goto error;
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   118
	/* forward user-defined signals */
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	if (sigaction(SIGUSR1, &sa, NULL) < 0)
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   120
		goto error;
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   121
	if (sigaction(SIGUSR2, &sa, NULL) < 0)
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   122
		goto error;
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   123
	/* propagate job control requests to worker */
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   124
	sa.sa_handler = forwardsignal;
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   125
	sa.sa_flags = SA_RESTART;
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   126
	if (sigaction(SIGCONT, &sa, NULL) < 0)
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   127
		goto error;
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   128
	sa.sa_handler = handlestopsignal;
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   129
	sa.sa_flags = SA_RESTART;
65d24ca35496 chg: forward job control signals to worker process (issue5051)
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parents: 28085
diff changeset
   130
	if (sigaction(SIGTSTP, &sa, NULL) < 0)
65d24ca35496 chg: forward job control signals to worker process (issue5051)
Yuya Nishihara <yuya@tcha.org>
parents: 28085
diff changeset
   131
		goto error;
29429
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   132
	/* get notified when pager exits */
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   133
	sa.sa_handler = handlechildsignal;
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   134
	sa.sa_flags = SA_RESTART;
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   135
	if (sigaction(SIGCHLD, &sa, NULL) < 0)
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   136
		goto error;
28086
65d24ca35496 chg: forward job control signals to worker process (issue5051)
Yuya Nishihara <yuya@tcha.org>
parents: 28085
diff changeset
   137
28085
c0d1bf1b26b7 chg: verify return value of sigaction() and sigemptyset()
Yuya Nishihara <yuya@tcha.org>
parents: 28084
diff changeset
   138
	return;
c0d1bf1b26b7 chg: verify return value of sigaction() and sigemptyset()
Yuya Nishihara <yuya@tcha.org>
parents: 28084
diff changeset
   139
c0d1bf1b26b7 chg: verify return value of sigaction() and sigemptyset()
Yuya Nishihara <yuya@tcha.org>
parents: 28084
diff changeset
   140
error:
28789
7f6e0a15189b chg: replace abortmsg showing errno with abortmsgerrno
Jun Wu <quark@fb.com>
parents: 28787
diff changeset
   141
	abortmsgerrno("failed to set up signal handlers");
28060
726f8d6cc324 chg: import frontend sources
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parents:
diff changeset
   142
}
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   143
30693
baee0f47b533 chg: add procutil.h
Jun Wu <quark@fb.com>
parents: 30692
diff changeset
   144
void restoresignalhandler(void)
29369
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   145
{
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   146
	struct sigaction sa;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   147
	memset(&sa, 0, sizeof(sa));
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   148
	sa.sa_handler = SIG_DFL;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   149
	sa.sa_flags = SA_RESTART;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   150
	if (sigemptyset(&sa.sa_mask) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   151
		goto error;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   152
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   153
	if (sigaction(SIGHUP, &sa, NULL) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   154
		goto error;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   155
	if (sigaction(SIGTERM, &sa, NULL) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   156
		goto error;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   157
	if (sigaction(SIGWINCH, &sa, NULL) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   158
		goto error;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   159
	if (sigaction(SIGCONT, &sa, NULL) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   160
		goto error;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   161
	if (sigaction(SIGTSTP, &sa, NULL) < 0)
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   162
		goto error;
29429
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   163
	if (sigaction(SIGCHLD, &sa, NULL) < 0)
cf99de051385 chg: send SIGPIPE to server immediately when pager exits (issue5278)
Jun Wu <quark@fb.com>
parents: 29370
diff changeset
   164
		goto error;
29369
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   165
29370
3ddf4d0c4170 chg: ignore SIGINT while waiting pager termination
Yuya Nishihara <yuya@tcha.org>
parents: 29369
diff changeset
   166
	/* ignore Ctrl+C while shutting down to make pager exits cleanly */
3ddf4d0c4170 chg: ignore SIGINT while waiting pager termination
Yuya Nishihara <yuya@tcha.org>
parents: 29369
diff changeset
   167
	sa.sa_handler = SIG_IGN;
3ddf4d0c4170 chg: ignore SIGINT while waiting pager termination
Yuya Nishihara <yuya@tcha.org>
parents: 29369
diff changeset
   168
	if (sigaction(SIGINT, &sa, NULL) < 0)
3ddf4d0c4170 chg: ignore SIGINT while waiting pager termination
Yuya Nishihara <yuya@tcha.org>
parents: 29369
diff changeset
   169
		goto error;
3ddf4d0c4170 chg: ignore SIGINT while waiting pager termination
Yuya Nishihara <yuya@tcha.org>
parents: 29369
diff changeset
   170
29369
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   171
	peerpid = 0;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   172
	return;
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   173
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   174
error:
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   175
	abortmsgerrno("failed to restore signal handlers");
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   176
}
85a18f3c0bdd chg: reset signal handlers to default before waiting pager
Yuya Nishihara <yuya@tcha.org>
parents: 29357
diff changeset
   177
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   178
/* This implementation is based on hgext/pager.py (post 369741ef7253)
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   179
 * Return 0 if pager is not started, or pid of the pager */
31941
ac5527021097 chg: respect environment variables for pager
Jun Wu <quark@fb.com>
parents: 31230
diff changeset
   180
pid_t setuppager(const char *pagercmd, const char *envp[])
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   181
{
30692
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   182
	assert(pagerpid == 0);
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   183
	if (!pagercmd)
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   184
		return 0;
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   185
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   186
	int pipefds[2];
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   187
	if (pipe(pipefds) < 0)
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   188
		return 0;
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   189
	pid_t pid = fork();
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   190
	if (pid < 0)
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   191
		goto error;
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   192
	if (pid > 0) {
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   193
		close(pipefds[0]);
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   194
		if (dup2(pipefds[1], fileno(stdout)) < 0)
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   195
			goto error;
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   196
		if (isatty(fileno(stderr))) {
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   197
			if (dup2(pipefds[1], fileno(stderr)) < 0)
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   198
				goto error;
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   199
		}
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   200
		close(pipefds[1]);
30692
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   201
		pagerpid = pid;
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   202
		return pid;
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   203
	} else {
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   204
		dup2(pipefds[0], fileno(stdin));
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   205
		close(pipefds[0]);
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   206
		close(pipefds[1]);
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   207
31941
ac5527021097 chg: respect environment variables for pager
Jun Wu <quark@fb.com>
parents: 31230
diff changeset
   208
		int r = execle("/bin/sh", "/bin/sh", "-c", pagercmd, NULL,
ac5527021097 chg: respect environment variables for pager
Jun Wu <quark@fb.com>
parents: 31230
diff changeset
   209
				envp);
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   210
		if (r < 0) {
28789
7f6e0a15189b chg: replace abortmsg showing errno with abortmsgerrno
Jun Wu <quark@fb.com>
parents: 28787
diff changeset
   211
			abortmsgerrno("cannot start pager '%s'", pagercmd);
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   212
		}
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   213
		return 0;
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   214
	}
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   215
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   216
error:
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   217
	close(pipefds[0]);
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   218
	close(pipefds[1]);
28789
7f6e0a15189b chg: replace abortmsg showing errno with abortmsgerrno
Jun Wu <quark@fb.com>
parents: 28787
diff changeset
   219
	abortmsgerrno("failed to prepare pager");
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   220
	return 0;
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   221
}
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   222
30693
baee0f47b533 chg: add procutil.h
Jun Wu <quark@fb.com>
parents: 30692
diff changeset
   223
void waitpager(void)
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   224
{
30692
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   225
	if (pagerpid == 0)
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   226
		return;
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   227
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   228
	/* close output streams to notify the pager its input ends */
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   229
	fclose(stdout);
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   230
	fclose(stderr);
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   231
	while (1) {
30692
23ddd43ba866 chg: let procutil maintain its own pagerpid
Jun Wu <quark@fb.com>
parents: 30691
diff changeset
   232
		pid_t ret = waitpid(pagerpid, NULL, 0);
29344
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   233
		if (ret == -1 && errno == EINTR)
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   234
			continue;
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   235
		break;
bb3d5c20eaf6 chg: exec pager in child process
Jun Wu <quark@fb.com>
parents: 29016
diff changeset
   236
	}
28060
726f8d6cc324 chg: import frontend sources
Yuya Nishihara <yuya@tcha.org>
parents:
diff changeset
   237
}