chg: fallback to original hg if stdio fds are missing

If stdio fds are missing (ex. fd 0 is not present), chg might open
fds that take the numbers 0, and attachio would send the wrong fds
to the client, which might cause unwanted behaviors. Avoid that by
detecting the missing fds and falling back to the original hg.

Differential Revision: https://phab.mercurial-scm.org/D9058

contrib/chg/chg.c

@@ -1,470 +1,484
 /*
  * A fast client for Mercurial command server
  *
  * Copyright (c) 2011 Yuya Nishihara <[e-mail]>
  *
  * 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 <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/file.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/un.h>
 #include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
 
 #include "hgclient.h"
 #include "procutil.h"
 #include "util.h"
 
 #ifndef PATH_MAX
 #define PATH_MAX 4096
 #endif
 
 struct cmdserveropts {
 	char sockname[PATH_MAX];
 	char initsockname[PATH_MAX];
 	char redirectsockname[PATH_MAX];
 	size_t argsize;
 	const char **args;
 };
 
 static void initcmdserveropts(struct cmdserveropts *opts)
 {
 	memset(opts, 0, sizeof(struct cmdserveropts));
 }
 
 static void freecmdserveropts(struct cmdserveropts *opts)
 {
 	free(opts->args);
 	opts->args = NULL;
 	opts->argsize = 0;
 }
 
 /*
  * Test if an argument is a sensitive flag that should be passed to the server.
  * Return 0 if not, otherwise the number of arguments starting from the current
  * one that should be passed to the server.
  */
 static size_t testsensitiveflag(const char *arg)
 {
 	static const struct {
 		const char *name;
 		size_t narg;
 	} flags[] = {
 	    {"--config", 1},     {"--cwd", 1},       {"--repo", 1},
 	    {"--repository", 1}, {"--traceback", 0}, {"-R", 1},
 	};
 	size_t i;
 	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); ++i) {
 		size_t len = strlen(flags[i].name);
 		size_t narg = flags[i].narg;
 		if (memcmp(arg, flags[i].name, len) == 0) {
 			if (arg[len] == '\0') {
 				/* --flag (value) */
 				return narg + 1;
 			} else if (arg[len] == '=' && narg > 0) {
 				/* --flag=value */
 				return 1;
 			} else if (flags[i].name[1] != '-') {
 				/* short flag */
 				return 1;
 			}
 		}
 	}
 	return 0;
 }
 
 /*
  * Parse argv[] and put sensitive flags to opts->args
  */
 static void setcmdserverargs(struct cmdserveropts *opts, int argc,
                              const char *argv[])
 {
 	size_t i, step;
 	opts->argsize = 0;
 	for (i = 0, step = 1; i < (size_t)argc; i += step, step = 1) {
 		if (!argv[i])
 			continue; /* pass clang-analyse */
 		if (strcmp(argv[i], "--") == 0)
 			break;
 		size_t n = testsensitiveflag(argv[i]);
 		if (n == 0 || i + n > (size_t)argc)
 			continue;
 		opts->args =
 		    reallocx(opts->args, (n + opts->argsize) * sizeof(char *));
 		memcpy(opts->args + opts->argsize, argv + i,
 		       sizeof(char *) * n);
 		opts->argsize += n;
 		step = n;
 	}
 }
 
 static void preparesockdir(const char *sockdir)
 {
 	int r;
 	r = mkdir(sockdir, 0700);
 	if (r < 0 && errno != EEXIST)
 		abortmsgerrno("cannot create sockdir %s", sockdir);
 
 	struct stat st;
 	r = lstat(sockdir, &st);
 	if (r < 0)
 		abortmsgerrno("cannot stat %s", sockdir);
 	if (!S_ISDIR(st.st_mode))
 		abortmsg("cannot create sockdir %s (file exists)", sockdir);
 	if (st.st_uid != geteuid() || st.st_mode & 0077)
 		abortmsg("insecure sockdir %s", sockdir);
 }
 
 /*
  * Check if a socket directory exists and is only owned by the current user.
  * Return 1 if so, 0 if not. This is used to check if XDG_RUNTIME_DIR can be
  * used or not. According to the specification [1], XDG_RUNTIME_DIR should be
  * ignored if the directory is not owned by the user with mode 0700.
  * [1]: https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
  */
 static int checkruntimedir(const char *sockdir)
 {
 	struct stat st;
 	int r = lstat(sockdir, &st);
 	if (r < 0) /* ex. does not exist */
 		return 0;
 	if (!S_ISDIR(st.st_mode)) /* ex. is a file, not a directory */
 		return 0;
 	return st.st_uid == geteuid() && (st.st_mode & 0777) == 0700;
 }
 
 static void getdefaultsockdir(char sockdir[], size_t size)
 {
 	/* by default, put socket file in secure directory
 	 * (${XDG_RUNTIME_DIR}/chg, or /${TMPDIR:-tmp}/chg$UID)
 	 * (permission of socket file may be ignored on some Unices) */
 	const char *runtimedir = getenv("XDG_RUNTIME_DIR");
 	int r;
 	if (runtimedir && checkruntimedir(runtimedir)) {
 		r = snprintf(sockdir, size, "%s/chg", runtimedir);
 	} else {
 		const char *tmpdir = getenv("TMPDIR");
 		if (!tmpdir)
 			tmpdir = "/tmp";
 		r = snprintf(sockdir, size, "%s/chg%d", tmpdir, geteuid());
 	}
 	if (r < 0 || (size_t)r >= size)
 		abortmsg("too long TMPDIR (r = %d)", r);
 }
 
 static void setcmdserveropts(struct cmdserveropts *opts)
 {
 	int r;
 	char sockdir[PATH_MAX];
 	const char *envsockname = getenv("CHGSOCKNAME");
 	if (!envsockname) {
 		getdefaultsockdir(sockdir, sizeof(sockdir));
 		preparesockdir(sockdir);
 	}
 
 	const char *basename = (envsockname) ? envsockname : sockdir;
 	const char *sockfmt = (envsockname) ? "%s" : "%s/server";
 	r = snprintf(opts->sockname, sizeof(opts->sockname), sockfmt, basename);
 	if (r < 0 || (size_t)r >= sizeof(opts->sockname))
 		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
 	r = snprintf(opts->initsockname, sizeof(opts->initsockname), "%s.%u",
 	             opts->sockname, (unsigned)getpid());
 	if (r < 0 || (size_t)r >= sizeof(opts->initsockname))
 		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
 }
 
 static const char *gethgcmd(void)
 {
 	static const char *hgcmd = NULL;
 	if (!hgcmd) {
 		hgcmd = getenv("CHGHG");
 		if (!hgcmd || hgcmd[0] == '\0')
 			hgcmd = getenv("HG");
 		if (!hgcmd || hgcmd[0] == '\0')
 #ifdef HGPATH
 			hgcmd = (HGPATH);
 #else
 			hgcmd = "hg";
 #endif
 	}
 	return hgcmd;
 }
 
 static void execcmdserver(const struct cmdserveropts *opts)
 {
 	const char *hgcmd = gethgcmd();
 
 	const char *baseargv[] = {
 	    hgcmd,
 	    "serve",
 	    "--cmdserver",
 	    "chgunix",
 	    "--address",
 	    opts->initsockname,
 	    "--daemon-postexec",
 	    "chdir:/",
 	};
 	size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]);
 	size_t argsize = baseargvsize + opts->argsize + 1;
 
 	const char **argv = mallocx(sizeof(char *) * argsize);
 	memcpy(argv, baseargv, sizeof(baseargv));
 	if (opts->args) {
 		size_t size = sizeof(char *) * opts->argsize;
 		memcpy(argv + baseargvsize, opts->args, size);
 	}
 	argv[argsize - 1] = NULL;
 
 	const char *lc_ctype_env = getenv("LC_CTYPE");
 	if (lc_ctype_env == NULL) {
 		if (putenv("CHG_CLEAR_LC_CTYPE=") != 0)
 			abortmsgerrno("failed to putenv CHG_CLEAR_LC_CTYPE");
 	} else {
 		if (setenv("CHGORIG_LC_CTYPE", lc_ctype_env, 1) != 0) {
 			abortmsgerrno("failed to setenv CHGORIG_LC_CTYPE");
 		}
 	}
 
 	if (putenv("CHGINTERNALMARK=") != 0)
 		abortmsgerrno("failed to putenv");
 	if (execvp(hgcmd, (char **)argv) < 0)
 		abortmsgerrno("failed to exec cmdserver");
 	free(argv);
 }
 
 /* Retry until we can connect to the server. Give up after some time. */
 static hgclient_t *retryconnectcmdserver(struct cmdserveropts *opts, pid_t pid)
 {
 	static const struct timespec sleepreq = {0, 10 * 1000000};
 	int pst = 0;
 
 	debugmsg("try connect to %s repeatedly", opts->initsockname);
 
 	unsigned int timeoutsec = 60; /* default: 60 seconds */
 	const char *timeoutenv = getenv("CHGTIMEOUT");
 	if (timeoutenv)
 		sscanf(timeoutenv, "%u", &timeoutsec);
 
 	for (unsigned int i = 0; !timeoutsec || i < timeoutsec * 100; i++) {
 		hgclient_t *hgc = hgc_open(opts->initsockname);
 		if (hgc) {
 			debugmsg("rename %s to %s", opts->initsockname,
 			         opts->sockname);
 			int r = rename(opts->initsockname, opts->sockname);
 			if (r != 0)
 				abortmsgerrno("cannot rename");
 			return hgc;
 		}
 
 		if (pid > 0) {
 			/* collect zombie if child process fails to start */
 			int r = waitpid(pid, &pst, WNOHANG);
 			if (r != 0)
 				goto cleanup;
 		}
 
 		nanosleep(&sleepreq, NULL);
 	}
 
 	abortmsg("timed out waiting for cmdserver %s", opts->initsockname);
 	return NULL;
 
 cleanup:
 	if (WIFEXITED(pst)) {
 		if (WEXITSTATUS(pst) == 0)
 			abortmsg("could not connect to cmdserver "
 			         "(exited with status 0)");
 		debugmsg("cmdserver exited with status %d", WEXITSTATUS(pst));
 		exit(WEXITSTATUS(pst));
 	} else if (WIFSIGNALED(pst)) {
 		abortmsg("cmdserver killed by signal %d", WTERMSIG(pst));
 	} else {
 		abortmsg("error while waiting for cmdserver");
 	}
 	return NULL;
 }
 
 /* Connect to a cmdserver. Will start a new server on demand. */
 static hgclient_t *connectcmdserver(struct cmdserveropts *opts)
 {
 	const char *sockname =
 	    opts->redirectsockname[0] ? opts->redirectsockname : opts->sockname;
 	debugmsg("try connect to %s", sockname);
 	hgclient_t *hgc = hgc_open(sockname);
 	if (hgc)
 		return hgc;
 
 	/* prevent us from being connected to an outdated server: we were
 	 * told by a server to redirect to opts->redirectsockname and that
 	 * address does not work. we do not want to connect to the server
 	 * again because it will probably tell us the same thing. */
 	if (sockname == opts->redirectsockname)
 		unlink(opts->sockname);
 
 	debugmsg("start cmdserver at %s", opts->initsockname);
 
 	pid_t pid = fork();
 	if (pid < 0)
 		abortmsg("failed to fork cmdserver process");
 	if (pid == 0) {
 		execcmdserver(opts);
 	} else {
 		hgc = retryconnectcmdserver(opts, pid);
 	}
 
 	return hgc;
 }
 
 static void killcmdserver(const struct cmdserveropts *opts)
 {
 	/* resolve config hash */
 	char *resolvedpath = realpath(opts->sockname, NULL);
 	if (resolvedpath) {
 		unlink(resolvedpath);
 		free(resolvedpath);
 	}
 }
 
 /* Run instructions sent from the server like unlink and set redirect path
  * Return 1 if reconnect is needed, otherwise 0 */
 static int runinstructions(struct cmdserveropts *opts, const char **insts)
 {
 	int needreconnect = 0;
 	if (!insts)
 		return needreconnect;
 
 	assert(insts);
 	opts->redirectsockname[0] = '\0';
 	const char **pinst;
 	for (pinst = insts; *pinst; pinst++) {
 		debugmsg("instruction: %s", *pinst);
 		if (strncmp(*pinst, "unlink ", 7) == 0) {
 			unlink(*pinst + 7);
 		} else if (strncmp(*pinst, "redirect ", 9) == 0) {
 			int r = snprintf(opts->redirectsockname,
 			                 sizeof(opts->redirectsockname), "%s",
 			                 *pinst + 9);
 			if (r < 0 || r >= (int)sizeof(opts->redirectsockname))
 				abortmsg("redirect path is too long (%d)", r);
 			needreconnect = 1;
 		} else if (strncmp(*pinst, "exit ", 5) == 0) {
 			int n = 0;
 			if (sscanf(*pinst + 5, "%d", &n) != 1)
 				abortmsg("cannot read the exit code");
 			exit(n);
 		} else if (strcmp(*pinst, "reconnect") == 0) {
 			needreconnect = 1;
 		} else {
 			abortmsg("unknown instruction: %s", *pinst);
 		}
 	}
 	return needreconnect;
 }
 
 /*
- * Test whether the command is unsupported or not. This is not designed to
- * cover all cases. But it's fast, does not depend on the server.
+ * Test whether the command and the environment is unsupported or not.
+ *
+ * If any of the stdio file descriptors are not present (rare, but some tools
+ * might spawn new processes without stdio instead of redirecting them to the
+ * null device), then mark it as not supported because attachio won't work
+ * correctly.
+ *
+ * The command list is not designed to cover all cases. But it's fast, and does
+ * not depend on the server.
  */
 static int isunsupported(int argc, const char *argv[])
 {
 	enum { SERVE = 1,
 	       DAEMON = 2,
 	       SERVEDAEMON = SERVE | DAEMON,
 	};
 	unsigned int state = 0;
 	int i;
+	/* use fcntl to test missing stdio fds */
+	if (fcntl(STDIN_FILENO, F_GETFD) == -1 ||
+	    fcntl(STDOUT_FILENO, F_GETFD) == -1 ||
+	    fcntl(STDERR_FILENO, F_GETFD) == -1) {
+		debugmsg("stdio fds are missing");
+		return 1;
+	}
 	for (i = 0; i < argc; ++i) {
 		if (strcmp(argv[i], "--") == 0)
 			break;
 		/*
 		 * there can be false positives but no false negative
 		 * we cannot assume `serve` will always be first argument
 		 * because global options can be passed before the command name
 		 */
 		if (strcmp("serve", argv[i]) == 0)
 			state |= SERVE;
 		else if (strcmp("-d", argv[i]) == 0 ||
 		         strcmp("--daemon", argv[i]) == 0)
 			state |= DAEMON;
 	}
 	return (state & SERVEDAEMON) == SERVEDAEMON;
 }
 
 static void execoriginalhg(const char *argv[])
 {
 	debugmsg("execute original hg");
 	if (execvp(gethgcmd(), (char **)argv) < 0)
 		abortmsgerrno("failed to exec original hg");
 }
 
 int main(int argc, const char *argv[], const char *envp[])
 {
 	if (getenv("CHGDEBUG"))
 		enabledebugmsg();
 
 	if (!getenv("HGPLAIN") && isatty(fileno(stderr)))
 		enablecolor();
 
 	if (getenv("CHGINTERNALMARK"))
 		abortmsg("chg started by chg detected.\n"
 		         "Please make sure ${HG:-hg} is not a symlink or "
 		         "wrapper to chg. Alternatively, set $CHGHG to the "
 		         "path of real hg.");
 
 	if (isunsupported(argc - 1, argv + 1))
 		execoriginalhg(argv);
 
 	struct cmdserveropts opts;
 	initcmdserveropts(&opts);
 	setcmdserveropts(&opts);
 	setcmdserverargs(&opts, argc, argv);
 
 	if (argc == 2) {
 		if (strcmp(argv[1], "--kill-chg-daemon") == 0) {
 			killcmdserver(&opts);
 			return 0;
 		}
 	}
 
 	hgclient_t *hgc;
 	size_t retry = 0;
 	while (1) {
 		hgc = connectcmdserver(&opts);
 		if (!hgc)
 			abortmsg("cannot open hg client");
 		hgc_setenv(hgc, envp);
 		const char **insts = hgc_validate(hgc, argv + 1, argc - 1);
 		int needreconnect = runinstructions(&opts, insts);
 		free(insts);
 		if (!needreconnect)
 			break;
 		hgc_close(hgc);
 		if (++retry > 10)
 			abortmsg("too many redirections.\n"
 			         "Please make sure %s is not a wrapper which "
 			         "changes sensitive environment variables "
 			         "before executing hg. If you have to use a "
 			         "wrapper, wrap chg instead of hg.",
 			         gethgcmd());
 	}
 
 	setupsignalhandler(hgc_peerpid(hgc), hgc_peerpgid(hgc));
 	atexit(waitpager);
 	int exitcode = hgc_runcommand(hgc, argv + 1, argc - 1);
 	restoresignalhandler();
 	hgc_close(hgc);
 	freecmdserveropts(&opts);
 
 	return exitcode;
 }

tests/test-chg.t

@@ -1,461 +1,469
 #require chg
 
   $ mkdir log
   $ cp $HGRCPATH $HGRCPATH.unconfigured
   $ cat <<'EOF' >> $HGRCPATH
   > [cmdserver]
   > log = $TESTTMP/log/server.log
   > max-log-files = 1
   > max-log-size = 10 kB
   > EOF
   $ cp $HGRCPATH $HGRCPATH.orig
 
   $ filterlog () {
   >   sed -e 's!^[0-9/]* [0-9:]* ([0-9]*)>!YYYY/MM/DD HH:MM:SS (PID)>!' \
   >       -e 's!\(setprocname\|received fds\|setenv\): .*!\1: ...!' \
   >       -e 's!\(confighash\|mtimehash\) = [0-9a-f]*!\1 = ...!g' \
   >       -e 's!\(in \)[0-9.]*s\b!\1 ...s!g' \
   >       -e 's!\(pid\)=[0-9]*!\1=...!g' \
   >       -e 's!\(/server-\)[0-9a-f]*!\1...!g'
   > }
 
 init repo
 
   $ chg init foo
   $ cd foo
 
 ill-formed config
 
   $ chg status
   $ echo '=brokenconfig' >> $HGRCPATH
   $ chg status
   hg: parse error at * (glob)
   [255]
 
   $ cp $HGRCPATH.orig $HGRCPATH
 
 long socket path
 
   $ sockpath=$TESTTMP/this/path/should/be/longer/than/one-hundred-and-seven/characters/where/107/is/the/typical/size/limit/of/unix-domain-socket
   $ mkdir -p $sockpath
   $ bakchgsockname=$CHGSOCKNAME
   $ CHGSOCKNAME=$sockpath/server
   $ export CHGSOCKNAME
   $ chg root
   $TESTTMP/foo
   $ rm -rf $sockpath
   $ CHGSOCKNAME=$bakchgsockname
   $ export CHGSOCKNAME
 
   $ cd ..
 
 editor
 ------
 
   $ cat >> pushbuffer.py <<EOF
   > def reposetup(ui, repo):
   >     repo.ui.pushbuffer(subproc=True)
   > EOF
 
   $ chg init editor
   $ cd editor
 
 by default, system() should be redirected to the client:
 
   $ touch foo
   $ CHGDEBUG= HGEDITOR=cat chg ci -Am channeled --edit 2>&1 \
   > | egrep "HG:|run 'cat"
   chg: debug: * run 'cat "*"' at '$TESTTMP/editor' (glob)
   HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   HG: Leave message empty to abort commit.
   HG: --
   HG: user: test
   HG: branch 'default'
   HG: added foo
 
 but no redirection should be made if output is captured:
 
   $ touch bar
   $ CHGDEBUG= HGEDITOR=cat chg ci -Am bufferred --edit \
   > --config extensions.pushbuffer="$TESTTMP/pushbuffer.py" 2>&1 \
   > | egrep "HG:|run 'cat"
   [1]
 
 check that commit commands succeeded:
 
   $ hg log -T '{rev}:{desc}\n'
   1:bufferred
   0:channeled
 
   $ cd ..
 
 pager
 -----
 
   $ cat >> fakepager.py <<EOF
   > import sys
   > for line in sys.stdin:
   >     sys.stdout.write('paged! %r\n' % line)
   > EOF
 
 enable pager extension globally, but spawns the master server with no tty:
 
   $ chg init pager
   $ cd pager
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > pager =
   > [pager]
   > pager = "$PYTHON" $TESTTMP/fakepager.py
   > EOF
   $ chg version > /dev/null
   $ touch foo
   $ chg ci -qAm foo
 
 pager should be enabled if the attached client has a tty:
 
   $ chg log -l1 -q --config ui.formatted=True
   paged! '0:1f7b0de80e11\n'
   $ chg log -l1 -q --config ui.formatted=False
   0:1f7b0de80e11
 
 chg waits for pager if runcommand raises
 
   $ cat > $TESTTMP/crash.py <<EOF
   > from mercurial import registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command(b'crash')
   > def pagercrash(ui, repo, *pats, **opts):
   >     ui.write(b'going to crash\n')
   >     raise Exception('.')
   > EOF
 
   $ cat > $TESTTMP/fakepager.py <<EOF
   > from __future__ import absolute_import
   > import sys
   > import time
   > for line in iter(sys.stdin.readline, ''):
   >     if 'crash' in line: # only interested in lines containing 'crash'
   >         # if chg exits when pager is sleeping (incorrectly), the output
   >         # will be captured by the next test case
   >         time.sleep(1)
   >         sys.stdout.write('crash-pager: %s' % line)
   > EOF
 
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > crash = $TESTTMP/crash.py
   > EOF
 
   $ chg crash --pager=on --config ui.formatted=True 2>/dev/null
   crash-pager: going to crash
   [255]
 
 no stdout data should be printed after pager quits, and the buffered data
 should never persist (issue6207)
 
 "killed!" may be printed if terminated by SIGPIPE, which isn't important
 in this test.
 
   $ cat > $TESTTMP/bulkwrite.py <<'EOF'
   > import time
   > from mercurial import error, registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command(b'bulkwrite')
   > def bulkwrite(ui, repo, *pats, **opts):
   >     ui.write(b'going to write massive data\n')
   >     ui.flush()
   >     t = time.time()
   >     while time.time() - t < 2:
   >         ui.write(b'x' * 1023 + b'\n')  # will be interrupted by SIGPIPE
   >     raise error.Abort(b"write() doesn't block")
   > EOF
 
   $ cat > $TESTTMP/fakepager.py <<'EOF'
   > import sys
   > import time
   > sys.stdout.write('paged! %r\n' % sys.stdin.readline())
   > time.sleep(1)  # new data will be written
   > EOF
 
   $ cat >> .hg/hgrc <<EOF
   > [extensions]
   > bulkwrite = $TESTTMP/bulkwrite.py
   > EOF
 
   $ chg bulkwrite --pager=on --color no --config ui.formatted=True
   paged! 'going to write massive data\n'
   killed! (?)
   [255]
 
   $ chg bulkwrite --pager=on --color no --config ui.formatted=True
   paged! 'going to write massive data\n'
   killed! (?)
   [255]
 
   $ cd ..
 
+missing stdio
+-------------
+
+  $ CHGDEBUG=1 chg version -q 0<&-
+  chg: debug: * stdio fds are missing (glob)
+  chg: debug: * execute original hg (glob)
+  Mercurial Distributed SCM * (glob)
+
 server lifecycle
 ----------------
 
 chg server should be restarted on code change, and old server will shut down
 automatically. In this test, we use the following time parameters:
 
  - "sleep 1" to make mtime different
  - "sleep 2" to notice mtime change (polling interval is 1 sec)
 
 set up repository with an extension:
 
   $ chg init extreload
   $ cd extreload
   $ touch dummyext.py
   $ cat <<EOF >> .hg/hgrc
   > [extensions]
   > dummyext = dummyext.py
   > EOF
 
 isolate socket directory for stable result:
 
   $ OLDCHGSOCKNAME=$CHGSOCKNAME
   $ mkdir chgsock
   $ CHGSOCKNAME=`pwd`/chgsock/server
 
 warm up server:
 
   $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
   chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)
 
 new server should be started if extension modified:
 
   $ sleep 1
   $ touch dummyext.py
   $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
   chg: debug: * instruction: unlink $TESTTMP/extreload/chgsock/server-* (glob)
   chg: debug: * instruction: reconnect (glob)
   chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)
 
 old server will shut down, while new server should still be reachable:
 
   $ sleep 2
   $ CHGDEBUG= chg log 2>&1 | (egrep 'instruction|start' || true)
 
 socket file should never be unlinked by old server:
 (simulates unowned socket by updating mtime, which makes sure server exits
 at polling cycle)
 
   $ ls chgsock/server-*
   chgsock/server-* (glob)
   $ touch chgsock/server-*
   $ sleep 2
   $ ls chgsock/server-*
   chgsock/server-* (glob)
 
 since no server is reachable from socket file, new server should be started:
 (this test makes sure that old server shut down automatically)
 
   $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
   chg: debug: * start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)
 
 shut down servers and restore environment:
 
   $ rm -R chgsock
   $ sleep 2
   $ CHGSOCKNAME=$OLDCHGSOCKNAME
   $ cd ..
 
 check that server events are recorded:
 
   $ ls log
   server.log
   server.log.1
 
 print only the last 10 lines, since we aren't sure how many records are
 preserved (since setprocname isn't available on py3 and pure version,
 the 10th-most-recent line is different when using py3):
 
   $ cat log/server.log.1 log/server.log | tail -10 | filterlog
   YYYY/MM/DD HH:MM:SS (PID)> confighash = ... mtimehash = ... (no-setprocname !)
   YYYY/MM/DD HH:MM:SS (PID)> forked worker process (pid=...)
   YYYY/MM/DD HH:MM:SS (PID)> setprocname: ... (setprocname !)
   YYYY/MM/DD HH:MM:SS (PID)> received fds: ...
   YYYY/MM/DD HH:MM:SS (PID)> chdir to '$TESTTMP/extreload'
   YYYY/MM/DD HH:MM:SS (PID)> setumask 18
   YYYY/MM/DD HH:MM:SS (PID)> setenv: ...
   YYYY/MM/DD HH:MM:SS (PID)> confighash = ... mtimehash = ...
   YYYY/MM/DD HH:MM:SS (PID)> validate: []
   YYYY/MM/DD HH:MM:SS (PID)> worker process exited (pid=...)
   YYYY/MM/DD HH:MM:SS (PID)> $TESTTMP/extreload/chgsock/server-... is not owned, exiting.
 
 global data mutated by schems
 -----------------------------
 
   $ hg init schemes
   $ cd schemes
 
 initial state
 
   $ cat > .hg/hgrc <<'EOF'
   > [extensions]
   > schemes =
   > [schemes]
   > foo = https://foo.example.org/
   > EOF
   $ hg debugexpandscheme foo://expanded
   https://foo.example.org/expanded
   $ hg debugexpandscheme bar://unexpanded
   bar://unexpanded
 
 add bar
 
   $ cat > .hg/hgrc <<'EOF'
   > [extensions]
   > schemes =
   > [schemes]
   > foo = https://foo.example.org/
   > bar = https://bar.example.org/
   > EOF
   $ hg debugexpandscheme foo://expanded
   https://foo.example.org/expanded
   $ hg debugexpandscheme bar://expanded
   https://bar.example.org/expanded
 
 remove foo
 
   $ cat > .hg/hgrc <<'EOF'
   > [extensions]
   > schemes =
   > [schemes]
   > bar = https://bar.example.org/
   > EOF
   $ hg debugexpandscheme foo://unexpanded
   foo://unexpanded
   $ hg debugexpandscheme bar://expanded
   https://bar.example.org/expanded
 
   $ cd ..
 
 repository cache
 ----------------
 
   $ rm log/server.log*
   $ cp $HGRCPATH.unconfigured $HGRCPATH
   $ cat <<'EOF' >> $HGRCPATH
   > [cmdserver]
   > log = $TESTTMP/log/server.log
   > max-repo-cache = 1
   > track-log = command, repocache
   > EOF
 
 isolate socket directory for stable result:
 
   $ OLDCHGSOCKNAME=$CHGSOCKNAME
   $ mkdir chgsock
   $ CHGSOCKNAME=`pwd`/chgsock/server
 
 create empty repo and cache it:
 
   $ hg init cached
   $ hg id -R cached
   000000000000 tip
   $ sleep 1
 
 modify repo (and cache will be invalidated):
 
   $ touch cached/a
   $ hg ci -R cached -Am 'add a'
   adding a
   $ sleep 1
 
 read cached repo:
 
   $ hg log -R cached
   changeset:   0:ac82d8b1f7c4
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     add a
   
   $ sleep 1
 
 discard cached from LRU cache:
 
   $ hg clone cached cached2
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg id -R cached2
   ac82d8b1f7c4 tip
   $ sleep 1
 
 read uncached repo:
 
   $ hg log -R cached
   changeset:   0:ac82d8b1f7c4
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     add a
   
   $ sleep 1
 
 shut down servers and restore environment:
 
   $ rm -R chgsock
   $ sleep 2
   $ CHGSOCKNAME=$OLDCHGSOCKNAME
 
 check server log:
 
   $ cat log/server.log | filterlog
   YYYY/MM/DD HH:MM:SS (PID)> worker process exited (pid=...)
   YYYY/MM/DD HH:MM:SS (PID)> worker process exited (pid=...) (?)
   YYYY/MM/DD HH:MM:SS (PID)> init cached
   YYYY/MM/DD HH:MM:SS (PID)> id -R cached
   YYYY/MM/DD HH:MM:SS (PID)> loaded repo into cache: $TESTTMP/cached (in  ...s)
   YYYY/MM/DD HH:MM:SS (PID)> repo from cache: $TESTTMP/cached
   YYYY/MM/DD HH:MM:SS (PID)> ci -R cached -Am 'add a'
   YYYY/MM/DD HH:MM:SS (PID)> loaded repo into cache: $TESTTMP/cached (in  ...s)
   YYYY/MM/DD HH:MM:SS (PID)> repo from cache: $TESTTMP/cached
   YYYY/MM/DD HH:MM:SS (PID)> log -R cached
   YYYY/MM/DD HH:MM:SS (PID)> loaded repo into cache: $TESTTMP/cached (in  ...s)
   YYYY/MM/DD HH:MM:SS (PID)> clone cached cached2
   YYYY/MM/DD HH:MM:SS (PID)> id -R cached2
   YYYY/MM/DD HH:MM:SS (PID)> loaded repo into cache: $TESTTMP/cached2 (in  ...s)
   YYYY/MM/DD HH:MM:SS (PID)> log -R cached
   YYYY/MM/DD HH:MM:SS (PID)> loaded repo into cache: $TESTTMP/cached (in  ...s)
 
 Test that chg works (sets to the user's actual LC_CTYPE) even when python
 "coerces" the locale (py3.7+)
 
   $ cat > $TESTTMP/debugenv.py <<EOF
   > from mercurial import encoding
   > from mercurial import registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command(b'debugenv', [], b'', norepo=True)
   > def debugenv(ui):
   >     for k in [b'LC_ALL', b'LC_CTYPE', b'LANG']:
   >         v = encoding.environ.get(k)
   >         if v is not None:
   >             ui.write(b'%s=%s\n' % (k, encoding.environ[k]))
   > EOF
 (hg keeps python's modified LC_CTYPE, chg doesn't)
   $ (unset LC_ALL; unset LANG; LC_CTYPE= "$CHGHG" \
   >    --config extensions.debugenv=$TESTTMP/debugenv.py debugenv)
   LC_CTYPE=C.UTF-8 (py37 !)
   LC_CTYPE= (no-py37 !)
   $ (unset LC_ALL; unset LANG; LC_CTYPE= chg \
   >    --config extensions.debugenv=$TESTTMP/debugenv.py debugenv)
   LC_CTYPE=
   $ (unset LC_ALL; unset LANG; LC_CTYPE=unsupported_value chg \
   >    --config extensions.debugenv=$TESTTMP/debugenv.py debugenv)
   LC_CTYPE=unsupported_value
   $ (unset LC_ALL; unset LANG; LC_CTYPE= chg \
   >    --config extensions.debugenv=$TESTTMP/debugenv.py debugenv)
   LC_CTYPE=
   $ LANG= LC_ALL= LC_CTYPE= chg \
   >    --config extensions.debugenv=$TESTTMP/debugenv.py debugenv
   LC_ALL=
   LC_CTYPE=
   LANG=