file: redo locking

kernel-src/sys/syscalls/pipe2.c

@@ -0,0 +1,73 @@
+#include <kernel/syscalls.h>
+#include <kernel/file.h>
+#include <kernel/vfs.h>
+#include <arch/cpu.h>
+#include <kernel/pipefs.h>
+#include <logging.h>
+#include <errno.h>
+
+static void open(file_t *file, vnode_t *node, int flags) {
+	file->vnode = node;
+	file->flags = flags;
+	file->offset = 0;
+	file->mode = 0777;
+	VOP_OPEN(&node, fileflagstovnodeflags(flags), &_cpu()->thread->proc->cred);
+}
+
+syscallret_t syscall_pipe2(context_t *, int flags) {
+	// TODO support them
+	__assert(flags == 0);
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	vnode_t *node = NULL;
+	int readfd, writefd;
+	file_t *readfile = NULL;
+	file_t *writefile = NULL;
+
+	ret.errno = pipefs_newpipe(&node);
+	if (ret.errno)
+		goto error;
+
+	// node held again because two files will point to the same node
+	VOP_HOLD(node);
+
+	ret.errno = fd_new(0, &readfile, &readfd);
+	if (ret.errno)
+		goto error;
+
+	open(readfile, node, FILE_READ);
+
+	ret.errno = fd_new(0, &writefile, &writefd);
+	if (ret.errno)
+		goto error;
+
+	open(writefile, node, FILE_WRITE);
+
+	ret.errno = 0;
+	ret.ret = (uint64_t)readfd | ((uint64_t)writefd << 32);
+	printf("pipe2: readfd %d writefd %d wrefcount %d\n", readfd, writefd, writefile->refcount);
+
+	return ret;
+
+	error:
+
+	if (readfile) {
+		fd_release(readfile);
+		fd_close(readfd);
+	}
+
+	if (writefile) {
+		fd_release(writefile);
+		fd_close(writefd);
+	}
+
+	if (node) {
+		// released twice because of two holds (one at pipefs_newpipe and the manual hold)
+		VOP_RELEASE(node);
+		VOP_RELEASE(node);
+	}
+
+	return ret;
+}