Re: Overlength socket paths (was Re: [COMMITTERS] pgsql: Refactor flex and bison make rules)

Noah Misch <noah(at)leadboat(dot)com> writes:
> Linux enforces a hard limit matching the static buffer in sockaddr_un. You'd
> proceed a bit further and hit "could not bind Unix socket: Invalid argument"
> or some such.

Hm, I was wondering about that. The Single Unix Spec suggests that
bind/connect ought to accept pathnames at least up to PATH_MAX, but
if popular implementations don't honor that then it is a bit pointless
for us to do a lot of pushups in userspace.

> I agree we should perhaps fix pg_upgrade to work even when its CWD is not
> usable as a socket path. It could create a temporary directory under /tmp and
> place the socket there, for example.

Yeah, I was starting to think that pg_upgrade's test script is the real
culprit here. Every other variant of "make check" just puts the socket
in the default place, typically /tmp, so it's rather useless that this
one place is doing things differently.

Another thing that we should possibly consider if we're going to hack on
that is that "make check" is not currently very friendly to people who
try to move the default socket location to someplace other than /tmp,
such as the ever-popular /var/run/postgresql. The reason that this is
problematic is that /var/run/postgresql may not be there at all in a
build environment, and if it is, it's likely not writable by the user
you're running your build as. So just using the default socket
directory isn't real friendly in any case. In converting the Fedora
packages to use /var/run/postgresql recently, I found I had to add the
attached crude hacks to support running the regression tests during
build. It'd be nice if the consideration were handled by unmodified
sources ...

regards, tom lane

diff -Naur postgresql-9.2.0.sockets/contrib/pg_upgrade/test.sh postgresql-9.2.0/contrib/pg_upgrade/test.sh
--- postgresql-9.2.0.sockets/contrib/pg_upgrade/test.sh 2012-09-06 17:26:17.000000000 -0400
+++ postgresql-9.2.0/contrib/pg_upgrade/test.sh 2012-09-06 18:13:18.178092176 -0400
@@ -62,10 +62,14 @@
rm -rf "$logdir"
mkdir "$logdir"

+# we want the Unix sockets in $temp_root
+PGHOST=$temp_root
+export PGHOST
+
set -x

$oldbindir/initdb
-$oldbindir/pg_ctl start -l "$logdir/postmaster1.log" -w
+$oldbindir/pg_ctl start -l "$logdir/postmaster1.log" -o "-c unix_socket_directories='$PGHOST'" -w
if "$MAKE" -C "$oldsrc" installcheck; then
pg_dumpall -f "$temp_root"/dump1.sql || pg_dumpall1_status=$?
if [ "$newsrc" != "$oldsrc" ]; then
@@ -108,7 +112,7 @@

pg_upgrade -d "${PGDATA}.old" -D "${PGDATA}" -b "$oldbindir" -B "$bindir"

-pg_ctl start -l "$logdir/postmaster2.log" -w
+pg_ctl start -l "$logdir/postmaster2.log" -o "-c unix_socket_directories='$PGHOST'" -w

if [ $testhost = Msys ] ; then
cmd /c analyze_new_cluster.bat
diff -Naur postgresql-9.2.0.sockets/src/test/regress/pg_regress.c postgresql-9.2.0/src/test/regress/pg_regress.c
--- postgresql-9.2.0.sockets/src/test/regress/pg_regress.c 2012-09-06 17:26:17.000000000 -0400
+++ postgresql-9.2.0/src/test/regress/pg_regress.c 2012-09-06 18:13:18.184092537 -0400
@@ -772,7 +772,7 @@
if (hostname != NULL)
doputenv("PGHOST", hostname);
else
- unsetenv("PGHOST");
+ doputenv("PGHOST", "/tmp");
unsetenv("PGHOSTADDR");
if (port != -1)
{
@@ -2233,7 +2233,7 @@
*/
header(_("starting postmaster"));
snprintf(buf, sizeof(buf),
- SYSTEMQUOTE "\"%s/postgres\" -D \"%s/data\" -F%s -c \"listen_addresses=%s\" > \"%s/log/postmaster.log\" 2>&1" SYSTEMQUOTE,
+ SYSTEMQUOTE "\"%s/postgres\" -D \"%s/data\" -F%s -c \"listen_addresses=%s\" -c \"unix_socket_directories=/tmp\" > \"%s/log/postmaster.log\" 2>&1" SYSTEMQUOTE,
bindir, temp_install,
debug ? " -d 5" : "",
hostname ? hostname : "",