From feed52d242f5f4fb2c7beacbbd27aac32bf6dd39 Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Sat, 15 Aug 2020 13:00:06 -0700
Subject: [PATCH] shlib.sh: provide git_ulimit function and var_xfsz_err

In order to implement the new $Girocco::Config::max_file_size512
setting, it's necessary to run git using the ulimit512 utility.

Provide a new git_ulimit function that does so if the max_file_size512
variable has been set to a non-zero value (otherwise just run git
normally).

While it would certainly be possible to always run git with the
limit in place, it's only needed during fetching/receiving of new
objects and it's better to avoid setting it during other operations
(especially gc) that could, perhaps, be adversely affected by such
a limit.

When a command fails because it receives SIGXFSZ (and it does not
have a signal handler for it installed), the shell will report that
as an exit status of 128+<signal number>.

Unfortunately, the actual signal number assigned to SIGXFSZ is not
standardized by POSIX (although it's likely 25 on many systems).

Therefore, test the actual failure at install time and set a new
"var_xfsz_err" variable to the exit code the shell will report for
a SIGXFSZ termination on the current system.  This makes it possible
to reliably test for such a failure later.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 shlib.sh | 44 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/shlib.sh b/shlib.sh
index 93a090d..171dadc 100644
--- a/shlib.sh
+++ b/shlib.sh
@@ -110,6 +110,7 @@ get_girocco_config_var_list() (
 	# var_xargs_r		A "-r" if xargs needs it to behave correctly
 	# var_du_exclude	Option to exclude PATTERN from du if available
 	# var_du_follow		Option to follow command line sym links if available
+	# var_xfsz_err		Shell error code when child dies from SIGXFSZ
 	_cfg_vars="$(get_girocco_config_pm_var_list)"
 	eval "$_cfg_vars"
 	printf '%s\n' "$_cfg_vars"
@@ -182,6 +183,23 @@ get_girocco_config_var_list() (
 		printf 'var_du_follow=%s\n' "-H"
 		break
 	fi
+	ul512bin="$inc_basedir/bin/ulimit512"
+	if [ ! -x "$ul512bin" ] && [ -x "$inc_basedir/src/ulimit512" ]; then
+		ul512bin="$inc_basedir/src/ulimit512"
+	fi
+	ebin="/bin/echo"
+	if [ ! -x "$ebin" ] && [ -x "/usr/bin/echo" ]; then
+		ebin="/usr/bin/echo"
+	fi
+	if [ -x "$ul512bin" ]; then
+		tmpfile="$(mktemp /tmp/ul512-$$-XXXXXX)"
+		ec=999
+		{ "$ul512bin" -f 0 "$ebin" test >"$tmpfile" || ec=$?; } >/dev/null 2>&1
+		rm -f "$tmpfile"
+		if [ "$ec" != 999 ] && [ "$ec" -gt 0 ]; then
+			printf 'var_xfsz_err=%s\n' "$ec"
+		fi
+	fi
 )
 
 # If basedir has been replaced, and shlib_vars.sh exists, get the config
@@ -320,15 +338,31 @@ clean_git_env() {
 # have to beware and explicitly unset any variables that should not persist
 # beyond the function call itself.
 
+_setexport_gitvars() {
+	[ z"${GIT_DIR+set}" != z"set" ]			|| export GIT_DIR
+	[ z"${GIT_SSL_NO_VERIFY+set}" != z"set" ]	|| export GIT_SSL_NO_VERIFY
+	[ z"${GIT_TRACE_PACKET+set}" != z"set" ]	|| export GIT_TRACE_PACKET
+	[ z"${GIT_USER_AGENT+set}" != z"set" ]		|| export GIT_USER_AGENT
+	[ z"${GIT_HTTP_USER_AGENT+set}" != z"set" ]	|| export GIT_HTTP_USER_AGENT
+}
+
 git() (
-	[ z"${GIT_DIR+set}" != z"set" ] || export GIT_DIR
-	[ z"${GIT_SSL_NO_VERIFY+set}" != z"set" ] || export GIT_SSL_NO_VERIFY
-	[ z"${GIT_TRACE_PACKET+set}" != z"set" ] || export GIT_TRACE_PACKET
-	[ z"${GIT_USER_AGENT+set}" != z"set" ] || export GIT_USER_AGENT
-	[ z"${GIT_HTTP_USER_AGENT+set}" != z"set" ] || export GIT_HTTP_USER_AGENT
+	_setexport_gitvars
 	exec "$cfg_git_bin" "$@"
 )
 
+# git_ulimit behaves the same as git except that it runs git using ulimit512
+# with the value of $cfg_max_file_size512 if that is set and greater than 0
+
+git_ulimit() (
+	_setexport_gitvars
+	if [ "${cfg_max_file_size512:-0}" = "0" ]; then
+		exec "$cfg_git_bin" "$@"
+	else
+		exec "$cfg_basedir/bin/ulimit512" -i -f "$cfg_max_file_size512" -- "$cfg_git_bin" "$@"
+	fi
+)
+
 # Since we do not yet require at least Git 1.8.5 this is a compatibility function
 # that allows us to use git update-ref --stdin where supported and the slow shell
 # script where not, but only the "delete" operation is currently supported.
-- 
2.11.4.GIT