kernel: poll system and poll syscall

kernel-src/include/kernel/devfs.h

@@ -3,6 +3,8 @@
 
 #include <kernel/vfs.h>
 
+#include <kernel/poll.h>
+
 #define DEV_MAJOR_NULL 1
 #define DEV_MAJOR_FULL 2
 #define DEV_MAJOR_ZERO 3
@@ -13,7 +15,7 @@ typedef struct {
 	int (*close)(int minor, int flags);
 	int (*read)(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *readc);
 	int (*write)(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *writec);
-	int (*poll)(int minor, int events);
+	int (*poll)(int minor, polldata_t *data, int events);
 	int (*mmap)(int minor, void *addr, uintmax_t offset, int flags);
 	int (*munmap)(int minor, void *addr, uintmax_t offset, int flags);
 	int (*isatty)(int minor);

kernel-src/include/kernel/poll.h

@@ -0,0 +1,43 @@
+#ifndef _POLL_H
+#define _POLL_H
+
+#include <kernel/scheduler.h>
+#include <spinlock.h>
+#include <mutex.h>
+
+struct polldata;
+
+typedef struct {
+	thread_t *thread;
+	spinlock_t lock;
+	mutex_t eventlock;
+	struct polldata *data;
+	struct polldata *event;
+	size_t size;
+} polldesc_t;
+
+typedef struct {
+	mutex_t lock;
+	struct polldata *data;
+} pollheader_t;
+
+typedef struct polldata {
+	struct polldata *next;
+	struct polldata *prev;
+	pollheader_t *header;
+	polldesc_t *desc;
+	int events;
+	int revents;
+} polldata_t;
+
+#define POLL_INITHEADER(x) \
+	MUTEX_INIT(&(x)->lock);
+
+int poll_initdesc(polldesc_t *, size_t size);
+void poll_add(pollheader_t *, polldata_t *, int events);
+void poll_leave(polldesc_t *);
+int poll_dowait(polldesc_t *);
+void poll_event(pollheader_t *, int events);
+void poll_destroydesc(polldesc_t *);
+
+#endif

kernel-src/include/kernel/vfs.h

@@ -72,6 +72,8 @@ typedef struct vfsops_t {
 	int (*root)(vfs_t *vfs, vnode_t **root);
 } vfsops_t;
 
+struct polldata;
+
 typedef struct vops_t {
 	int (*open)(vnode_t **node, int flags, cred_t *cred);
 	int (*close)(vnode_t *node, int flags, cred_t *cred);
@@ -81,7 +83,7 @@ typedef struct vops_t {
 	int (*create)(vnode_t *parent, char *name, vattr_t *attr, int type, vnode_t **result, cred_t *cred);
 	int (*getattr)(vnode_t *node, vattr_t *attr, cred_t *cred);
 	int (*setattr)(vnode_t *node, vattr_t *attr, cred_t *cred);
-	int (*poll)(vnode_t *node, int events);
+	int (*poll)(vnode_t *node, struct polldata *, int events);
 	int (*access)(vnode_t *node, mode_t mode, cred_t *cred);
 	int (*unlink)(vnode_t *node, char *name, cred_t *cred);
 	int (*link)(vnode_t *node, vnode_t *dir, char *name, cred_t *cred);
@@ -119,7 +121,7 @@ typedef struct vops_t {
 #define VOP_MMAP(v, a, o, f, c) (v)->ops->mmap(v, a, o, f, c)
 #define VOP_MUNMAP(v, a, o, f, c) (v)->ops->munmap(v, a, o, f, c)
 #define VOP_GETDENTS(v, b, c, o, rc) (v)->ops->getdents(v, b, c, o, rc)
-#define VOP_POLL(v, p) (v)->ops->poll(v, p)
+#define VOP_POLL(v, d, p) (v)->ops->poll(v, d, p)
 #define VOP_ISATTY(v) ((v)->ops->isatty ? (v)->ops->isatty(v) : ENOTTY)
 #define VOP_IOCTL(v, r, a, rp) ((v)->ops->ioctl ? (v)->ops->ioctl(v, r, a, rp) : ENOTTY)
 #define VOP_HOLD(v) __atomic_add_fetch(&(v)->refcount, 1, __ATOMIC_SEQ_CST)
@@ -143,6 +145,7 @@ int vfs_read(vnode_t *node, void *buffer, size_t size, uintmax_t offset, size_t
 int vfs_create(vnode_t *ref, char *path, vattr_t *attr, int type, vnode_t **node);
 int vfs_link(vnode_t *destref, char *destpath, vnode_t *linkref, char *linkpath, int type, vattr_t *attr);
 int vfs_unlink(vnode_t *ref, char *path);
+int vfs_pollstub(vnode_t *node, struct polldata *, int events);
 
 #define VFS_LOOKUP_PARENT 1
 #define VFS_LOOKUP_NOLINK 2