# HG changeset patch
# User Jun Wu <qu...@fb.com>
# Date 1482185700 0
# Mon Dec 19 22:15:00 2016 +0000
# Node ID 467f4027b8d0162e3e8f09cd0cc0ca627164bce1
# Parent 24534dee38fe515f2c406e18153f623a074148b3
# Available At https://bitbucket.org/quark-zju/hg-draft
# hg pull https://bitbucket.org/quark-zju/hg-draft -r 467f4027b8d0
chg: remove locks
See the previous two patches for the reason. The advantage is a simplified
code base and better throughput when starting multiple servers with multiple
confighashes. The disadvantage is starting multiple servers in parallel with
a single confighash will waste some CPU time, which is probably fine in
common use-cases.
This makes it easier to switch to relative paths to support long unix domain
socket paths.
diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
--- a/contrib/chg/chg.c
+++ b/contrib/chg/chg.c
@@ -34,8 +34,6 @@ struct cmdserveropts {
char initsockname[UNIX_PATH_MAX];
char redirectsockname[UNIX_PATH_MAX];
- char lockfile[UNIX_PATH_MAX];
size_t argsize;
const char **args;
- int lockfd;
int sockdirfd;
};
@@ -43,5 +41,4 @@ struct cmdserveropts {
static void initcmdserveropts(struct cmdserveropts *opts) {
memset(opts, 0, sizeof(struct cmdserveropts));
- opts->lockfd = -1;
opts->sockdirfd = -1;
}
@@ -51,5 +48,4 @@ static void freecmdserveropts(struct cmd
opts->args = NULL;
opts->argsize = 0;
- assert(opts->lockfd == -1 && "should be closed by unlockcmdserver()");
if (opts->sockdirfd >= 0) {
close(opts->sockdirfd);
@@ -158,11 +154,7 @@ static void setcmdserveropts(struct cmds
const char *basename = (envsockname) ? envsockname : sockdir;
const char *sockfmt = (envsockname) ? "%s" : "%s/server";
- const char *lockfmt = (envsockname) ? "%s.lock" : "%s/lock";
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->lockfile, sizeof(opts->lockfile), lockfmt, basename);
- if (r < 0 || (size_t)r >= sizeof(opts->lockfile))
- abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
r = snprintf(opts->initsockname, sizeof(opts->initsockname),
"%s.%u", opts->sockname, (unsigned)getpid());
@@ -171,37 +163,4 @@ static void setcmdserveropts(struct cmds
}
-/*
- * Acquire a file lock that indicates a client is trying to start and connect
- * to a server, before executing a command. The lock is released upon exit or
- * explicit unlock. Will block if the lock is held by another process.
- */
-static void lockcmdserver(struct cmdserveropts *opts)
-{
- if (opts->lockfd == -1) {
- opts->lockfd = open(opts->lockfile,
- O_RDWR | O_CREAT | O_NOFOLLOW, 0600);
- if (opts->lockfd == -1)
- abortmsgerrno("cannot create lock file %s",
- opts->lockfile);
- fsetcloexec(opts->lockfd);
- }
- int r = flock(opts->lockfd, LOCK_EX);
- if (r == -1)
- abortmsgerrno("cannot acquire lock");
-}
-
-/*
- * Release the file lock held by calling lockcmdserver. Will do nothing if
- * lockcmdserver is not called.
- */
-static void unlockcmdserver(struct cmdserveropts *opts)
-{
- if (opts->lockfd == -1)
- return;
- flock(opts->lockfd, LOCK_UN);
- close(opts->lockfd);
- opts->lockfd = -1;
-}
-
static const char *gethgcmd(void)
{
@@ -309,12 +268,4 @@ static hgclient_t *connectcmdserver(stru
return hgc;
- lockcmdserver(opts);
- hgc = hgc_open(sockname);
- if (hgc) {
- unlockcmdserver(opts);
- debugmsg("cmdserver is started by another process");
- return hgc;
- }
-
/* prevent us from being connected to an outdated server: we were
* told by a server to redirect to opts->redirectsockname and that
@@ -335,5 +286,4 @@ static hgclient_t *connectcmdserver(stru
}
- unlockcmdserver(opts);
return hgc;
}
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