spawn: Actually fix moving the pipe out of the way

We have to check in_fd after out_fd, otherwise the dup() may move it to
in_fd.

1 files changed, 7 insertions, 7 deletions

diff --git a/spawn.c b/spawn.c
index bcd2c08..b356c41 100644
--- a/spawn.c
+++ b/spawn.c
@@ -147,13 +147,7 @@ static void bfs_spawn_exec(const char *exe, const struct bfs_spawn *ctx, char **
 	close(pipefd[0]);
 
 	for (const struct bfs_spawn_action *action = actions; action; action = action->next) {
-		// Pretend the error-reporting pipe doesn't exist
-		if (action->in_fd == pipefd[1]) {
-			errno = EBADF;
-			goto fail;
-		}
-
-		// Move the pipe out of the way if necessary
+		// Move the error-reporting pipe out of the way if necessary...
 		if (action->out_fd == pipefd[1]) {
 			int fd = dup_cloexec(pipefd[1]);
 			if (fd < 0) {
@@ -163,6 +157,12 @@ static void bfs_spawn_exec(const char *exe, const struct bfs_spawn *ctx, char **
 			pipefd[1] = fd;
 		}
 
+		// ... and pretend the pipe doesn't exist
+		if (action->in_fd == pipefd[1]) {
+			errno = EBADF;
+			goto fail;
+		}
+
 		switch (action->op) {
 		case BFS_SPAWN_CLOSE:
 			if (close(action->out_fd) != 0) {