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/*
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* A fast client for Mercurial command server
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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 <fcntl.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/un.h>
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#include <sys/wait.h>
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#include <time.h>
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#include <unistd.h>
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#include "hgclient.h"
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#include "util.h"
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#ifndef UNIX_PATH_MAX
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#define UNIX_PATH_MAX (sizeof(((struct sockaddr_un *)NULL)->sun_path))
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#endif
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struct cmdserveropts {
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char sockname[UNIX_PATH_MAX];
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char lockfile[UNIX_PATH_MAX];
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char pidfile[UNIX_PATH_MAX];
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size_t argsize;
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const char **args;
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int lockfd;
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};
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static void initcmdserveropts(struct cmdserveropts *opts) {
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memset(opts, 0, sizeof(struct cmdserveropts));
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opts->lockfd = -1;
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}
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static void freecmdserveropts(struct cmdserveropts *opts) {
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free(opts->args);
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opts->args = NULL;
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opts->argsize = 0;
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}
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/*
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* Test if an argument is a sensitive flag that should be passed to the server.
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* Return 0 if not, otherwise the number of arguments starting from the current
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* one that should be passed to the server.
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*/
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static size_t testsensitiveflag(const char *arg)
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{
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static const struct {
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const char *name;
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size_t narg;
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} flags[] = {
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{"--config", 1},
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{"--cwd", 1},
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{"--repo", 1},
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{"--repository", 1},
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{"--traceback", 0},
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{"-R", 1},
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};
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size_t i;
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for (i = 0; i < sizeof(flags) / sizeof(flags[0]); ++i) {
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size_t len = strlen(flags[i].name);
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size_t narg = flags[i].narg;
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if (memcmp(arg, flags[i].name, len) == 0) {
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if (arg[len] == '\0') { /* --flag (value) */
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return narg + 1;
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} else if (arg[len] == '=' && narg > 0) { /* --flag=value */
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return 1;
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} else if (flags[i].name[1] != '-') { /* short flag */
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return 1;
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}
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}
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}
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return 0;
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}
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/*
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* Parse argv[] and put sensitive flags to opts->args
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*/
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static void setcmdserverargs(struct cmdserveropts *opts,
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int argc, const char *argv[])
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{
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size_t i, step;
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opts->argsize = 0;
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for (i = 0, step = 1; i < (size_t)argc; i += step, step = 1) {
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if (!argv[i])
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continue; /* pass clang-analyse */
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if (strcmp(argv[i], "--") == 0)
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break;
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size_t n = testsensitiveflag(argv[i]);
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if (n == 0 || i + n > (size_t)argc)
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continue;
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opts->args = reallocx(opts->args,
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(n + opts->argsize) * sizeof(char *));
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memcpy(opts->args + opts->argsize, argv + i,
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sizeof(char *) * n);
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opts->argsize += n;
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step = n;
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}
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}
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static void preparesockdir(const char *sockdir)
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{
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int r;
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r = mkdir(sockdir, 0700);
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if (r < 0 && errno != EEXIST)
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abortmsg("cannot create sockdir %s (errno = %d)",
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sockdir, errno);
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struct stat st;
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r = lstat(sockdir, &st);
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if (r < 0)
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abortmsg("cannot stat %s (errno = %d)", sockdir, errno);
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if (!S_ISDIR(st.st_mode))
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abortmsg("cannot create sockdir %s (file exists)", sockdir);
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if (st.st_uid != geteuid() || st.st_mode & 0077)
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abortmsg("insecure sockdir %s", sockdir);
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}
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static void setcmdserveropts(struct cmdserveropts *opts)
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{
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int r;
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char sockdir[UNIX_PATH_MAX];
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const char *envsockname = getenv("CHGSOCKNAME");
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if (!envsockname) {
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/* by default, put socket file in secure directory
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* (permission of socket file may be ignored on some Unices) */
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const char *tmpdir = getenv("TMPDIR");
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if (!tmpdir)
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tmpdir = "/tmp";
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r = snprintf(sockdir, sizeof(sockdir), "%s/chg%d",
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tmpdir, geteuid());
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if (r < 0 || (size_t)r >= sizeof(sockdir))
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abortmsg("too long TMPDIR (r = %d)", r);
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preparesockdir(sockdir);
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}
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const char *basename = (envsockname) ? envsockname : sockdir;
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const char *sockfmt = (envsockname) ? "%s" : "%s/server";
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const char *lockfmt = (envsockname) ? "%s.lock" : "%s/lock";
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const char *pidfmt = (envsockname) ? "%s.pid" : "%s/pid";
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r = snprintf(opts->sockname, sizeof(opts->sockname), sockfmt, basename);
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if (r < 0 || (size_t)r >= sizeof(opts->sockname))
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abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
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r = snprintf(opts->lockfile, sizeof(opts->lockfile), lockfmt, basename);
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if (r < 0 || (size_t)r >= sizeof(opts->lockfile))
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abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
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r = snprintf(opts->pidfile, sizeof(opts->pidfile), pidfmt, basename);
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if (r < 0 || (size_t)r >= sizeof(opts->pidfile))
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abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
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}
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/*
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* Acquire a file lock that indicates a client is trying to start and connect
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* to a server, before executing a command. The lock is released upon exit or
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* explicit unlock. Will block if the lock is held by another process.
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*/
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static void lockcmdserver(struct cmdserveropts *opts)
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{
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if (opts->lockfd == -1) {
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opts->lockfd = open(opts->lockfile, O_RDWR | O_CREAT | O_NOFOLLOW, 0600);
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if (opts->lockfd == -1)
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abortmsg("cannot create lock file %s", opts->lockfile);
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}
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int r = flock(opts->lockfd, LOCK_EX);
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if (r == -1)
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abortmsg("cannot acquire lock");
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}
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/*
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* Release the file lock held by calling lockcmdserver. Will do nothing if
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* lockcmdserver is not called.
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*/
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static void unlockcmdserver(struct cmdserveropts *opts)
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{
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if (opts->lockfd == -1)
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return;
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flock(opts->lockfd, LOCK_UN);
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close(opts->lockfd);
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opts->lockfd = -1;
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}
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static void execcmdserver(const struct cmdserveropts *opts)
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{
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const char *hgcmd = getenv("CHGHG");
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if (!hgcmd || hgcmd[0] == '\0')
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hgcmd = getenv("HG");
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if (!hgcmd || hgcmd[0] == '\0')
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hgcmd = "hg";
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const char *baseargv[] = {
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hgcmd,
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"serve",
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"--cwd", "/",
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"--cmdserver", "chgunix",
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"--address", opts->sockname,
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"--daemon-postexec", "none",
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"--pid-file", opts->pidfile,
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"--config", "extensions.chgserver=",
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/* wrap root ui so that it can be disabled/enabled by config */
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"--config", "progress.assume-tty=1",
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};
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size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]);
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size_t argsize = baseargvsize + opts->argsize + 1;
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const char **argv = mallocx(sizeof(char *) * argsize);
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memcpy(argv, baseargv, sizeof(baseargv));
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memcpy(argv + baseargvsize, opts->args, sizeof(char *) * opts->argsize);
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argv[argsize - 1] = NULL;
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if (execvp(hgcmd, (char **)argv) < 0)
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abortmsg("failed to exec cmdserver (errno = %d)", errno);
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free(argv);
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}
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/* Retry until we can connect to the server. Give up after some time. */
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static hgclient_t *retryconnectcmdserver(struct cmdserveropts *opts, pid_t pid)
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{
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static const struct timespec sleepreq = {0, 10 * 1000000};
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int pst = 0;
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for (unsigned int i = 0; i < 10 * 100; i++) {
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hgclient_t *hgc = hgc_open(opts->sockname);
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if (hgc)
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return hgc;
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if (pid > 0) {
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/* collect zombie if child process fails to start */
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int r = waitpid(pid, &pst, WNOHANG);
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if (r != 0)
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goto cleanup;
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}
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nanosleep(&sleepreq, NULL);
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}
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abortmsg("timed out waiting for cmdserver %s", opts->sockname);
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return NULL;
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cleanup:
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if (WIFEXITED(pst)) {
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abortmsg("cmdserver exited with status %d", WEXITSTATUS(pst));
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} else if (WIFSIGNALED(pst)) {
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abortmsg("cmdserver killed by signal %d", WTERMSIG(pst));
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} else {
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abortmsg("error white waiting cmdserver");
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}
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return NULL;
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}
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/* Connect to a cmdserver. Will start a new server on demand. */
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static hgclient_t *connectcmdserver(struct cmdserveropts *opts)
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{
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hgclient_t *hgc = hgc_open(opts->sockname);
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if (hgc)
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return hgc;
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lockcmdserver(opts);
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hgc = hgc_open(opts->sockname);
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if (hgc) {
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unlockcmdserver(opts);
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debugmsg("cmdserver is started by another process");
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return hgc;
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}
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debugmsg("start cmdserver at %s", opts->sockname);
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pid_t pid = fork();
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if (pid < 0)
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abortmsg("failed to fork cmdserver process");
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|
if (pid == 0) {
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/* do not leak lockfd to hg */
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close(opts->lockfd);
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/* bypass uisetup() of pager extension */
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int nullfd = open("/dev/null", O_WRONLY);
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|
if (nullfd >= 0) {
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dup2(nullfd, fileno(stdout));
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|
close(nullfd);
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|
}
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execcmdserver(opts);
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|
} else {
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|
hgc = retryconnectcmdserver(opts, pid);
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|
}
|
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|
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unlockcmdserver(opts);
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|
return hgc;
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}
|
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|
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static void killcmdserver(const struct cmdserveropts *opts, int sig)
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|
{
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FILE *fp = fopen(opts->pidfile, "r");
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|
if (!fp)
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|
abortmsg("cannot open %s (errno = %d)", opts->pidfile, errno);
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|
int pid = 0;
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|
int n = fscanf(fp, "%d", &pid);
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|
fclose(fp);
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|
if (n != 1 || pid <= 0)
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|
abortmsg("cannot read pid from %s", opts->pidfile);
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if (kill((pid_t)pid, sig) < 0) {
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|
if (errno == ESRCH)
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|
return;
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|
abortmsg("cannot kill %d (errno = %d)", pid, errno);
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|
}
|
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|
}
|
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|
|
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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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|
abortmsg("cannot kill %d (errno = %d)", peerpid, errno);
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|
debugmsg("forward signal %d", sig);
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|
}
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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);
|
|
|
if (raise(sig) < 0) /* resend to self */
|
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|
goto error;
|
|
|
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;
|
|
|
/* resent signal will be handled before sigprocmask() returns */
|
|
|
if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
|
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|
goto error;
|
|
|
if (sigaction(sig, &oldsa, NULL) < 0)
|
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|
goto error;
|
|
|
return;
|
|
|
|
|
|
error:
|
|
|
abortmsg("failed to handle stop signal (errno = %d)", errno);
|
|
|
}
|
|
|
|
|
|
static void setupsignalhandler(pid_t pid)
|
|
|
{
|
|
|
if (pid <= 0)
|
|
|
return;
|
|
|
peerpid = pid;
|
|
|
|
|
|
struct sigaction sa;
|
|
|
memset(&sa, 0, sizeof(sa));
|
|
|
sa.sa_handler = forwardsignal;
|
|
|
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_flags |= SA_RESETHAND;
|
|
|
if (sigaction(SIGTERM, &sa, NULL) < 0)
|
|
|
goto error;
|
|
|
|
|
|
/* 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;
|
|
|
|
|
|
return;
|
|
|
|
|
|
error:
|
|
|
abortmsg("failed to set up signal handlers (errno = %d)", errno);
|
|
|
}
|
|
|
|
|
|
/* This implementation is based on hgext/pager.py (pre 369741ef7253) */
|
|
|
static void setuppager(hgclient_t *hgc, const char *const args[],
|
|
|
size_t argsize)
|
|
|
{
|
|
|
const char *pagercmd = hgc_getpager(hgc, args, argsize);
|
|
|
if (!pagercmd)
|
|
|
return;
|
|
|
|
|
|
int pipefds[2];
|
|
|
if (pipe(pipefds) < 0)
|
|
|
return;
|
|
|
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]);
|
|
|
hgc_attachio(hgc); /* reattach to pager */
|
|
|
return;
|
|
|
} else {
|
|
|
dup2(pipefds[0], fileno(stdin));
|
|
|
close(pipefds[0]);
|
|
|
close(pipefds[1]);
|
|
|
|
|
|
int r = execlp("/bin/sh", "/bin/sh", "-c", pagercmd, NULL);
|
|
|
if (r < 0) {
|
|
|
abortmsg("cannot start pager '%s' (errno = %d)",
|
|
|
pagercmd, errno);
|
|
|
}
|
|
|
return;
|
|
|
}
|
|
|
|
|
|
error:
|
|
|
close(pipefds[0]);
|
|
|
close(pipefds[1]);
|
|
|
abortmsg("failed to prepare pager (errno = %d)", errno);
|
|
|
}
|
|
|
|
|
|
int main(int argc, const char *argv[], const char *envp[])
|
|
|
{
|
|
|
if (getenv("CHGDEBUG"))
|
|
|
enabledebugmsg();
|
|
|
|
|
|
struct cmdserveropts opts;
|
|
|
initcmdserveropts(&opts);
|
|
|
setcmdserveropts(&opts);
|
|
|
setcmdserverargs(&opts, argc, argv);
|
|
|
|
|
|
if (argc == 2) {
|
|
|
int sig = 0;
|
|
|
if (strcmp(argv[1], "--kill-chg-daemon") == 0)
|
|
|
sig = SIGTERM;
|
|
|
if (strcmp(argv[1], "--reload-chg-daemon") == 0)
|
|
|
sig = SIGHUP;
|
|
|
if (sig > 0) {
|
|
|
killcmdserver(&opts, sig);
|
|
|
return 0;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
hgclient_t *hgc = connectcmdserver(&opts);
|
|
|
if (!hgc)
|
|
|
abortmsg("cannot open hg client");
|
|
|
|
|
|
setupsignalhandler(hgc_peerpid(hgc));
|
|
|
hgc_setenv(hgc, envp);
|
|
|
setuppager(hgc, argv + 1, argc - 1);
|
|
|
int exitcode = hgc_runcommand(hgc, argv + 1, argc - 1);
|
|
|
hgc_close(hgc);
|
|
|
freecmdserveropts(&opts);
|
|
|
return exitcode;
|
|
|
}
|
|
|
|