Merge branch 'ie/config-includeif-hostname' into seen

The conditional inclusion mechanism for configuration files learned
to switch on the hostname.

* ie/config-includeif-hostname:
  config: learn the "hostname:" includeIf condition
  t: add a test helper for getting hostname

Documentation/config.txt

@@ -188,6 +188,12 @@ As for the naming of this keyword, it is for forwards compatibility with
 a naming scheme that supports more variable-based include conditions,
 but currently Git only supports the exact keyword described above.
 
+`hostname`::
+	The data that follows the keyword `hostname:` is taken to be a
+	pattern with standard globbing wildcards. If the current
+	hostname (output of gethostname(2)) matches the
+	pattern, the include condition is met.
+
 A few more notes on matching via `gitdir` and `gitdir/i`:
 
  * Symlinks in `$GIT_DIR` are not resolved before matching.
@@ -263,6 +269,10 @@ Example
 	path = foo.inc
 [remote "origin"]
 	url = https://example.com/git
+
+; include only if the hostname of the machine matches some-hostname
+[includeIf "hostname:some-hostname"]
+	path = foo.inc
 ----
 
 Values

Makefile

@@ -854,6 +854,7 @@ TEST_BUILTINS_OBJS += test-userdiff.o
 TEST_BUILTINS_OBJS += test-wildmatch.o
 TEST_BUILTINS_OBJS += test-windows-named-pipe.o
 TEST_BUILTINS_OBJS += test-write-cache.o
+TEST_BUILTINS_OBJS += test-xgethostname.o
 TEST_BUILTINS_OBJS += test-xml-encode.o
 
 # Do not add more tests here unless they have extra dependencies. Add

config.c

@@ -317,6 +317,21 @@ static int include_by_branch(const char *cond, size_t cond_len)
 	return ret;
 }
 
+static int include_by_hostname(const char *cond, size_t cond_len)
+{
+	int ret;
+	char my_host[HOST_NAME_MAX + 1];
+	struct strbuf pattern = STRBUF_INIT;
+
+	if (xgethostname(my_host, sizeof(my_host)))
+		return 0;
+
+	strbuf_add(&pattern, cond, cond_len);
+	ret = !wildmatch(pattern.buf, my_host, 0);
+	strbuf_release(&pattern);
+	return ret;
+}
+
 static int add_remote_url(const char *var, const char *value,
 			  const struct config_context *ctx UNUSED, void *data)
 {
@@ -406,6 +421,8 @@ static int include_condition_is_true(const struct key_value_info *kvi,
 	else if (skip_prefix_mem(cond, cond_len, "hasconfig:remote.*.url:", &cond,
 				   &cond_len))
 		return include_by_remote_url(inc, cond, cond_len);
+	else if (skip_prefix_mem(cond, cond_len, "hostname:", &cond, &cond_len))
+		return include_by_hostname(cond, cond_len);
 
 	/* unknown conditionals are always false */
 	return 0;

t/helper/test-tool.c

@@ -88,6 +88,7 @@ static struct test_cmd cmds[] = {
 	{ "truncate", cmd__truncate },
 	{ "userdiff", cmd__userdiff },
 	{ "urlmatch-normalization", cmd__urlmatch_normalization },
+	{ "xgethostname", cmd__xgethostname },
 	{ "xml-encode", cmd__xml_encode },
 	{ "wildmatch", cmd__wildmatch },
 #ifdef GIT_WINDOWS_NATIVE

t/helper/test-tool.h

@@ -81,6 +81,7 @@ int cmd__trace2(int argc, const char **argv);
 int cmd__truncate(int argc, const char **argv);
 int cmd__userdiff(int argc, const char **argv);
 int cmd__urlmatch_normalization(int argc, const char **argv);
+int cmd__xgethostname(int argc, const char **argv);
 int cmd__xml_encode(int argc, const char **argv);
 int cmd__wildmatch(int argc, const char **argv);
 #ifdef GIT_WINDOWS_NATIVE

t/helper/test-xgethostname.c

@@ -0,0 +1,12 @@
+#include "test-tool.h"
+
+int cmd__xgethostname(int argc, const char **argv)
+{
+	char hostname[HOST_NAME_MAX + 1];
+
+	if (xgethostname(hostname, sizeof(hostname)))
+		die("unable to get the host name");
+
+	puts(hostname);
+	return 0;
+}

t/t1305-config-include.sh

@@ -357,4 +357,46 @@ test_expect_success 'include cycles are detected' '
 	grep "exceeded maximum include depth" stderr
 '
 
+test_expect_success 'conditional include, hostname' '
+	cat >>.git/config <<-EOF &&
+	[includeIf "hostname:$(test-tool xgethostname)a"]
+		path = bar12
+	EOF
+	cat >>.git/bar12 <<-EOF &&
+	[test]
+		twelve=12
+	EOF
+
+	test_must_fail git config test.twelve &&
+
+	cat >>.git/config <<-EOF &&
+	[includeIf "hostname:$(test-tool xgethostname)"]
+		path = bar12
+	EOF
+	echo 12 >expect &&
+	git config test.twelve >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'conditional include, hostname, wildcard' '
+	cat >>.git/config <<-EOF &&
+	[includeIf "hostname:$(test-tool xgethostname)a*"]
+		path = bar13
+	EOF
+	cat >>.git/bar13 <<-EOF &&
+	[test]
+		thirteen = 13
+	EOF
+
+	test_must_fail git config test.thirteen &&
+
+	cat >>.git/config <<-EOF &&
+	[includeIf "hostname:$(test-tool xgethostname)*"]
+		path = bar13
+	EOF
+	echo 13 >expect &&
+	git config test.thirteen >actual &&
+	test_cmp expect actual
+'
+
 test_done

t/t6500-gc.sh

@@ -379,7 +379,6 @@ test_expect_success 'background auto gc respects lock for all operations' '
 
 	# now fake a concurrent gc that holds the lock; we can use our
 	# shell pid so that it looks valid.
-	hostname=$(hostname || echo unknown) &&
 	shell_pid=$$ &&
 	if test_have_prereq MINGW && test -f /proc/$shell_pid/winpid
 	then
@@ -388,7 +387,7 @@ test_expect_success 'background auto gc respects lock for all operations' '
 		# the Windows PID in this case.
 		shell_pid=$(cat /proc/$shell_pid/winpid)
 	fi &&
-	printf "%d %s" "$shell_pid" "$hostname" >.git/gc.pid &&
+	printf "%d %s" "$shell_pid" "$(test-tool xgethostname)" >.git/gc.pid &&
 
 	# our gc should exit zero without doing anything
 	run_and_wait_for_auto_gc &&