1 files changed, 51 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/stdio/fopen.c b/libc-top-half/musl/src/stdio/fopen.c
new file mode 100644
index 0000000..670f438
--- /dev/null
+++ b/libc-top-half/musl/src/stdio/fopen.c
@@ -0,0 +1,51 @@
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
+#else
+#include <unistd.h>
+#include <wasi/libc.h>
+#endif
+#include "stdio_impl.h"
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+
+FILE *fopen(const char *restrict filename, const char *restrict mode)
+{
+	FILE *f;
+	int fd;
+	int flags;
+
+	/* Check for valid initial mode character */
+	if (!strchr("rwa", *mode)) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	/* Compute the flags to pass to open() */
+	flags = __fmodeflags(mode);
+
+#ifdef __wasilibc_unmodified_upstream // WASI has no sys_open
+	fd = sys_open(filename, flags, 0666);
+#else
+	// WASI libc ignores the mode parameter anyway, so skip the varargs.
+	fd = __wasilibc_open_nomode(filename, flags);
+#endif
+	if (fd < 0) return 0;
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
+	if (flags & O_CLOEXEC)
+		__syscall(SYS_fcntl, fd, F_SETFD, FD_CLOEXEC);
+#else
+	/* Avoid __syscall, but also, FD_CLOEXEC is not supported in WASI. */
+#endif
+
+	f = __fdopen(fd, mode);
+	if (f) return f;
+
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
+	__syscall(SYS_close, fd);
+#else
+	close(fd);
+#endif
+	return 0;
+}
+
+weak_alias(fopen, fopen64);