xref: /libuv/src/unix/poll.c (revision 6b0051d1)
1 /* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
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3  * Permission is hereby granted, free of charge, to any person obtaining a copy
4  * of this software and associated documentation files (the "Software"), to
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7  * sell copies of the Software, and to permit persons to whom the Software is
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10  * The above copyright notice and this permission notice shall be included in
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13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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19  * IN THE SOFTWARE.
20  */
21 
22 #include "uv.h"
23 #include "internal.h"
24 
25 #include <unistd.h>
26 #include <assert.h>
27 #include <errno.h>
28 
29 
uv__poll_io(uv_loop_t * loop,uv__io_t * w,unsigned int events)30 static void uv__poll_io(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
31   uv_poll_t* handle;
32   int pevents;
33 
34   handle = container_of(w, uv_poll_t, io_watcher);
35 
36   /*
37    * As documented in the kernel source fs/kernfs/file.c #780
38    * poll will return POLLERR|POLLPRI in case of sysfs
39    * polling. This does not happen in case of out-of-band
40    * TCP messages.
41    *
42    * The above is the case on (at least) FreeBSD and Linux.
43    *
44    * So to properly determine a POLLPRI or a POLLERR we need
45    * to check for both.
46    */
47   if ((events & POLLERR) && !(events & UV__POLLPRI)) {
48     uv__io_stop(loop, w, POLLIN | POLLOUT | UV__POLLRDHUP | UV__POLLPRI);
49     uv__handle_stop(handle);
50     handle->poll_cb(handle, UV_EBADF, 0);
51     return;
52   }
53 
54   pevents = 0;
55   if (events & POLLIN)
56     pevents |= UV_READABLE;
57   if (events & UV__POLLPRI)
58     pevents |= UV_PRIORITIZED;
59   if (events & POLLOUT)
60     pevents |= UV_WRITABLE;
61   if (events & UV__POLLRDHUP)
62     pevents |= UV_DISCONNECT;
63 
64   handle->poll_cb(handle, 0, pevents);
65 }
66 
67 
uv_poll_init(uv_loop_t * loop,uv_poll_t * handle,int fd)68 int uv_poll_init(uv_loop_t* loop, uv_poll_t* handle, int fd) {
69   int err;
70 
71   if (uv__fd_exists(loop, fd))
72     return UV_EEXIST;
73 
74   err = uv__io_check_fd(loop, fd);
75   if (err)
76     return err;
77 
78   /* If ioctl(FIONBIO) reports ENOTTY, try fcntl(F_GETFL) + fcntl(F_SETFL).
79    * Workaround for e.g. kqueue fds not supporting ioctls.
80    */
81   err = uv__nonblock(fd, 1);
82 #if UV__NONBLOCK_IS_IOCTL
83   if (err == UV_ENOTTY)
84     err = uv__nonblock_fcntl(fd, 1);
85 #endif
86 
87   if (err)
88     return err;
89 
90   uv__handle_init(loop, (uv_handle_t*) handle, UV_POLL);
91   uv__io_init(&handle->io_watcher, uv__poll_io, fd);
92   handle->poll_cb = NULL;
93   return 0;
94 }
95 
96 
uv_poll_init_socket(uv_loop_t * loop,uv_poll_t * handle,uv_os_sock_t socket)97 int uv_poll_init_socket(uv_loop_t* loop, uv_poll_t* handle,
98     uv_os_sock_t socket) {
99   return uv_poll_init(loop, handle, socket);
100 }
101 
102 
uv__poll_stop(uv_poll_t * handle)103 static void uv__poll_stop(uv_poll_t* handle) {
104   uv__io_stop(handle->loop,
105               &handle->io_watcher,
106               POLLIN | POLLOUT | UV__POLLRDHUP | UV__POLLPRI);
107   uv__handle_stop(handle);
108   uv__platform_invalidate_fd(handle->loop, handle->io_watcher.fd);
109 }
110 
111 
uv_poll_stop(uv_poll_t * handle)112 int uv_poll_stop(uv_poll_t* handle) {
113   assert(!uv__is_closing(handle));
114   uv__poll_stop(handle);
115   return 0;
116 }
117 
118 
uv_poll_start(uv_poll_t * handle,int pevents,uv_poll_cb poll_cb)119 int uv_poll_start(uv_poll_t* handle, int pevents, uv_poll_cb poll_cb) {
120   uv__io_t** watchers;
121   uv__io_t* w;
122   int events;
123 
124   assert((pevents & ~(UV_READABLE | UV_WRITABLE | UV_DISCONNECT |
125                       UV_PRIORITIZED)) == 0);
126   assert(!uv__is_closing(handle));
127 
128   watchers = handle->loop->watchers;
129   w = &handle->io_watcher;
130 
131   if (uv__fd_exists(handle->loop, w->fd))
132     if (watchers[w->fd] != w)
133       return UV_EEXIST;
134 
135   uv__poll_stop(handle);
136 
137   if (pevents == 0)
138     return 0;
139 
140   events = 0;
141   if (pevents & UV_READABLE)
142     events |= POLLIN;
143   if (pevents & UV_PRIORITIZED)
144     events |= UV__POLLPRI;
145   if (pevents & UV_WRITABLE)
146     events |= POLLOUT;
147   if (pevents & UV_DISCONNECT)
148     events |= UV__POLLRDHUP;
149 
150   uv__io_start(handle->loop, &handle->io_watcher, events);
151   uv__handle_start(handle);
152   handle->poll_cb = poll_cb;
153 
154   return 0;
155 }
156 
157 
uv__poll_close(uv_poll_t * handle)158 void uv__poll_close(uv_poll_t* handle) {
159   uv__poll_stop(handle);
160 }
161