Merge branch 'jn/run-command-error-failure' into maint

* jn/run-command-error-failure:
  run-command: handle short writes and EINTR in die_child
  tests: check error message from run_command

run-command.c

@@ -67,21 +67,24 @@ static int child_notifier = -1;
 
 static void notify_parent(void)
 {
-	ssize_t unused;
-	unused = write(child_notifier, "", 1);
+	/*
+	 * execvp failed.  If possible, we'd like to let start_command
+	 * know, so failures like ENOENT can be handled right away; but
+	 * otherwise, finish_command will still report the error.
+	 */
+	xwrite(child_notifier, "", 1);
 }
 
 static NORETURN void die_child(const char *err, va_list params)
 {
 	char msg[4096];
-	ssize_t unused;
 	int len = vsnprintf(msg, sizeof(msg), err, params);
 	if (len > sizeof(msg))
 		len = sizeof(msg);
 
-	unused = write(child_err, "fatal: ", 7);
-	unused = write(child_err, msg, len);
-	unused = write(child_err, "\n", 1);
+	write_in_full(child_err, "fatal: ", 7);
+	write_in_full(child_err, msg, len);
+	write_in_full(child_err, "\n", 1);
 	exit(128);
 }
 #endif

t/t0061-run-command.sh

@@ -7,8 +7,31 @@ test_description='Test run command'
 
 . ./test-lib.sh
 
+cat >hello-script <<-EOF
+	#!$SHELL_PATH
+	cat hello-script
+EOF
+>empty
+
 test_expect_success 'start_command reports ENOENT' '
 	test-run-command start-command-ENOENT ./does-not-exist
 '
 
+test_expect_success 'run_command can run a command' '
+	cat hello-script >hello.sh &&
+	chmod +x hello.sh &&
+	test-run-command run-command ./hello.sh >actual 2>err &&
+
+	test_cmp hello-script actual &&
+	test_cmp empty err
+'
+
+test_expect_success POSIXPERM 'run_command reports EACCES' '
+	cat hello-script >hello.sh &&
+	chmod -x hello.sh &&
+	test_must_fail test-run-command run-command ./hello.sh 2>err &&
+
+	grep "fatal: cannot exec.*hello.sh" err
+'
+
 test_done

test-run-command.c

@@ -29,6 +29,8 @@ int main(int argc, char **argv)
 		fprintf(stderr, "FAIL %s\n", argv[1]);
 		return 1;
 	}
+	if (!strcmp(argv[1], "run-command"))
+		exit(run_command(&proc));
 
 	fprintf(stderr, "check usage\n");
 	return 1;