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From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: Johannes Schindelin <johannes.schindelin@gmx.de>,
	Junio C Hamano <gitster@pobox.com>,
	Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: [PATCH 1/4] mingw: demonstrate that all file handles are inherited by child processes
Date: Fri, 22 Nov 2019 14:41:02 +0000
Message-ID: <96608fd2e82b7337dea4ea9fb7a2f3f1f7e6c854.1574433665.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.670.git.git.1574433665.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When spawning child processes, we really should be careful which file
handles we let them inherit.

This is doubly important on Windows, where we cannot rename, delete, or
modify files if there is still a file handle open.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/helper/test-run-command.c | 44 +++++++++++++++++++++++++++++++++++++
 t/t0061-run-command.sh      |  4 ++++
 2 files changed, 48 insertions(+)

diff --git a/t/helper/test-run-command.c b/t/helper/test-run-command.c
index ead6dc611a..40ec4dbb6e 100644
--- a/t/helper/test-run-command.c
+++ b/t/helper/test-run-command.c
@@ -200,6 +200,46 @@ static int testsuite(int argc, const char **argv)
 	return !!ret;
 }
 
+static int inherit_handle(const char *argv0)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	char path[PATH_MAX];
+	int tmp;
+
+	/* First, open an inheritable handle */
+	xsnprintf(path, sizeof(path), "out-XXXXXX");
+	tmp = xmkstemp(path);
+
+	argv_array_pushl(&cp.args,
+			 "test-tool", argv0, "inherited-handle-child", NULL);
+	cp.in = -1;
+	cp.no_stdout = cp.no_stderr = 1;
+	if (start_command(&cp) < 0)
+		die("Could not start child process");
+
+	/* Then close it, and try to delete it. */
+	close(tmp);
+	if (unlink(path))
+		die("Could not delete '%s'", path);
+
+	if (close(cp.in) < 0 || finish_command(&cp) < 0)
+		die("Child did not finish");
+
+	return 0;
+}
+
+static int inherit_handle_child(void)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	if (strbuf_read(&buf, 0, 0) < 0)
+		die("Could not read stdin");
+	printf("Received %s\n", buf.buf);
+	strbuf_release(&buf);
+
+	return 0;
+}
+
 int cmd__run_command(int argc, const char **argv)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
@@ -207,6 +247,10 @@ int cmd__run_command(int argc, const char **argv)
 
 	if (argc > 1 && !strcmp(argv[1], "testsuite"))
 		exit(testsuite(argc - 1, argv + 1));
+	if (!strcmp(argv[1], "inherited-handle"))
+		exit(inherit_handle(argv[0]));
+	if (!strcmp(argv[1], "inherited-handle-child"))
+		exit(inherit_handle_child());
 
 	if (argc < 3)
 		return 1;
diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index 17c9c0f3bb..473a3405ef 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -12,6 +12,10 @@ cat >hello-script <<-EOF
 	cat hello-script
 EOF
 
+test_expect_failure MINGW 'subprocess inherits only std handles' '
+	test-tool run-command inherited-handle
+'
+
 test_expect_success 'start_command reports ENOENT (slash)' '
 	test-tool run-command start-command-ENOENT ./does-not-exist 2>err &&
 	test_i18ngrep "\./does-not-exist" err
-- 
gitgitgadget


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-22 14:41 [PATCH 0/4] On Windows, limit which file handles are inherited by spawned " Johannes Schindelin via GitGitGadget
2019-11-22 14:41 ` Johannes Schindelin via GitGitGadget [this message]
2019-11-22 14:41 ` [PATCH 2/4] mingw: work around incorrect standard handles Johannes Schindelin via GitGitGadget
2019-11-22 14:41 ` [PATCH 3/4] mingw: spawned processes need to inherit only " Johannes Schindelin via GitGitGadget
2019-11-28 21:48   ` Johannes Sixt
2019-11-29 13:52     ` Johannes Schindelin
2019-11-29 20:40       ` Johannes Schindelin
2019-11-29 22:19       ` Johannes Sixt
2019-11-29 22:37       ` Johannes Sixt
2019-11-30 22:10         ` Johannes Schindelin
2019-11-22 14:41 ` [PATCH 4/4] mingw: restrict file handle inheritance only on Windows 7 and later Johannes Schindelin via GitGitGadget
2019-11-25  5:42 ` [PATCH 0/4] On Windows, limit which file handles are inherited by spawned child processes Junio C Hamano
2019-11-25 16:29   ` Johannes Schindelin

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