script: use memfd_create instead of O_TMPFILE

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 7 insertions, 15 deletions

diff --git a/Makefile b/Makefile
index 5e2eb7b..74383b6 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ BINDIR ?= $(PREFIX)/bin
 MANDIR ?= $(PREFIX)/share/man
 
 CFLAGS ?= -O3 -march=native
-CFLAGS += -std=c99 -Wall
+CFLAGS += -std=gnu99 -Wall -D_GNU_SOURCE
 
 all: cscript
 
diff --git a/cscript.c b/cscript.c
index c7dbcf5..65ab92a 100644
--- a/cscript.c
+++ b/cscript.c
@@ -1,10 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0
  *
- * Copyright (C) 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright (C) 2018-2021 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
-#define _GNU_SOURCE
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -12,11 +10,12 @@
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/mman.h>
 #include <fcntl.h>
 
 int main(int argc, char *argv[], char *envp[])
 {
-	int fd, fd2, input = -1, pipes[2] = { 0 }, status;
+	int fd, input = -1, pipes[2] = { 0 }, status;
 	pid_t compiler_pid;
 	char *output_path;
 
@@ -34,9 +33,9 @@ int main(int argc, char *argv[], char *envp[])
 		}
 	}
 
-	fd = open(getenv("HOME") ?: getenv("TMPDIR") ?: "/tmp", O_TMPFILE | O_EXCL | O_RDWR, S_IWUSR | S_IRUSR);
+	fd = memfd_create("cscript", 0);
 	if (fd < 0) {
-		perror("Error: unable to create temporary inode");
+		perror("Error: unable to create memfd");
 		return 1;
 	}
 	if (asprintf(&output_path, "/proc/self/fd/%d", fd) < 0) {
@@ -94,14 +93,7 @@ int main(int argc, char *argv[], char *envp[])
 		return 1;
 	}
 
-	fd2 = open(output_path, O_RDONLY);
-	if (fd2 < 0) {
-		perror("Error: unable to reopen temporary inode");
-		return 1;
-	}
-	close(fd);
-
-	if (fexecve(fd2, argv, envp) < 0) {
+	if (fexecve(fd, argv, envp) < 0) {
 		perror("Error: could not execute compiled program");
 		return 1;
 	}