Adding upstream version 0.0~git20221206.8b7148f.upstream/0.0_git20221206.8b7148f

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/libc-top-half/musl/src/stdio/freopen.c b/libc-top-half/musl/src/stdio/freopen.c
new file mode 100644
index 0000000..5331db0
--- /dev/null
+++ b/libc-top-half/musl/src/stdio/freopen.c
@@ -0,0 +1,80 @@
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall, dup
+#include "stdio_impl.h"
+#else
+#include <wasi/libc.h>
+#endif
+#include <fcntl.h>
+#include <unistd.h>
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall, dup
+#else
+// Move this below fcntl.h and unistd.h so that the __syscall macro doesn't
+// cause trouble.
+#include "stdio_impl.h"
+#endif
+
+/* The basic idea of this implementation is to open a new FILE,
+ * hack the necessary parts of the new FILE into the old one, then
+ * close the new FILE. */
+
+/* Locking IS necessary because another thread may provably hold the
+ * lock, via flockfile or otherwise, when freopen is called, and in that
+ * case, freopen cannot act until the lock is released. */
+
+FILE *freopen(const char *restrict filename, const char *restrict mode, FILE *restrict f)
+{
+	int fl = __fmodeflags(mode);
+	FILE *f2;
+
+	FLOCK(f);
+
+	fflush(f);
+
+	if (!filename) {
+		if (fl&O_CLOEXEC)
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
+			__syscall(SYS_fcntl, f->fd, F_SETFD, FD_CLOEXEC);
+#else
+			fcntl(f->fd, F_SETFD, FD_CLOEXEC);
+#endif
+		fl &= ~(O_CREAT|O_EXCL|O_CLOEXEC);
+#ifdef __wasilibc_unmodified_upstream // WASI has no syscall
+		if (syscall(SYS_fcntl, f->fd, F_SETFL, fl) < 0)
+#else
+		if (fcntl(f->fd, F_SETFL, fl) < 0)
+#endif
+			goto fail;
+	} else {
+		f2 = fopen(filename, mode);
+		if (!f2) goto fail;
+		if (f2->fd == f->fd) f2->fd = -1; /* avoid closing in fclose */
+#ifdef __wasilibc_unmodified_upstream // WASI has no dup
+		else if (__dup3(f2->fd, f->fd, fl&O_CLOEXEC)<0) goto fail2;
+#else
+		// WASI doesn't have dup3, but does have a way to renumber
+		// an existing file descriptor.
+		else {
+			if (__wasilibc_fd_renumber(f2->fd, f->fd)<0) goto fail2;
+			f2->fd = -1; /* avoid closing in fclose */
+		}
+#endif
+
+		f->flags = (f->flags & F_PERM) | f2->flags;
+		f->read = f2->read;
+		f->write = f2->write;
+		f->seek = f2->seek;
+		f->close = f2->close;
+
+		fclose(f2);
+	}
+
+	FUNLOCK(f);
+	return f;
+
+fail2:
+	fclose(f2);
+fail:
+	fclose(f);
+	return NULL;
+}
+
+weak_alias(freopen, freopen64);