| 1 | /* |
| 2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of the GNU General Public License as published by the Free |
| 6 | * Software Foundation; only version 2 of the License. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 11 | * more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License along with |
| 14 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple |
| 15 | * Place - Suite 330, Boston, MA 02111-1307, USA. |
| 16 | */ |
| 17 | |
| 18 | #ifndef _LTT_POLL_H |
| 19 | #define _LTT_POLL_H |
| 20 | |
| 21 | #include <string.h> |
| 22 | #include <unistd.h> |
| 23 | |
| 24 | #include <common/common.h> |
| 25 | |
| 26 | /* |
| 27 | * Maximum number of fd we can monitor. |
| 28 | * |
| 29 | * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will |
| 30 | * be used for the maximum size of the poll set. If this interface is not |
| 31 | * available, according to the manpage, the max_user_watches value is 1/25 (4%) |
| 32 | * of the available low memory divided by the registration cost in bytes which |
| 33 | * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel. |
| 34 | * |
| 35 | * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by |
| 36 | * getrlimit(2). |
| 37 | */ |
| 38 | extern unsigned int poll_max_size; |
| 39 | |
| 40 | /* |
| 41 | * Used by lttng_poll_clean to free the events structure in a lttng_poll_event. |
| 42 | */ |
| 43 | static inline void __lttng_poll_free(void *events) |
| 44 | { |
| 45 | free(events); |
| 46 | } |
| 47 | |
| 48 | /* |
| 49 | * epoll(7) implementation. |
| 50 | */ |
| 51 | #ifdef HAVE_EPOLL |
| 52 | #include <sys/epoll.h> |
| 53 | #include <stdio.h> |
| 54 | |
| 55 | /* See man epoll(7) for this define path */ |
| 56 | #define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches" |
| 57 | |
| 58 | enum { |
| 59 | /* Polling variables compatibility for epoll */ |
| 60 | LPOLLIN = EPOLLIN, |
| 61 | LPOLLPRI = EPOLLPRI, |
| 62 | LPOLLOUT = EPOLLOUT, |
| 63 | LPOLLRDNORM = EPOLLRDNORM, |
| 64 | LPOLLRDBAND = EPOLLRDBAND, |
| 65 | LPOLLWRNORM = EPOLLWRNORM, |
| 66 | LPOLLWRBAND = EPOLLWRBAND, |
| 67 | LPOLLMSG = EPOLLMSG, |
| 68 | LPOLLERR = EPOLLERR, |
| 69 | LPOLLHUP = EPOLLHUP, |
| 70 | LPOLLNVAL = EPOLLHUP, |
| 71 | LPOLLRDHUP = EPOLLRDHUP, |
| 72 | /* Close on exec feature of epoll */ |
| 73 | LTTNG_CLOEXEC = EPOLL_CLOEXEC, |
| 74 | }; |
| 75 | |
| 76 | struct compat_epoll_event { |
| 77 | int epfd; |
| 78 | uint32_t nb_fd; /* Current number of fd in events */ |
| 79 | uint32_t events_size; /* Size of events array */ |
| 80 | struct epoll_event *events; |
| 81 | }; |
| 82 | #define lttng_poll_event compat_epoll_event |
| 83 | |
| 84 | /* |
| 85 | * For the following calls, consider 'e' to be a lttng_poll_event pointer and i |
| 86 | * being the index of the events array. |
| 87 | */ |
| 88 | #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd |
| 89 | #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events |
| 90 | #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd |
| 91 | #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size |
| 92 | |
| 93 | /* |
| 94 | * Create the epoll set. No memory allocation is done here. |
| 95 | */ |
| 96 | extern int compat_epoll_create(struct lttng_poll_event *events, |
| 97 | int size, int flags); |
| 98 | #define lttng_poll_create(events, size, flags) \ |
| 99 | compat_epoll_create(events, size, flags) |
| 100 | |
| 101 | /* |
| 102 | * Wait on epoll set with the number of fd registered to the lttng_poll_event |
| 103 | * data structure (events). |
| 104 | */ |
| 105 | extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout); |
| 106 | #define lttng_poll_wait(events, timeout) \ |
| 107 | compat_epoll_wait(events, timeout) |
| 108 | |
| 109 | /* |
| 110 | * Add a fd to the epoll set and resize the epoll_event structure if needed. |
| 111 | */ |
| 112 | extern int compat_epoll_add(struct lttng_poll_event *events, |
| 113 | int fd, uint32_t req_events); |
| 114 | #define lttng_poll_add(events, fd, req_events) \ |
| 115 | compat_epoll_add(events, fd, req_events) |
| 116 | |
| 117 | /* |
| 118 | * Remove a fd from the epoll set. |
| 119 | */ |
| 120 | extern int compat_epoll_del(struct lttng_poll_event *events, int fd); |
| 121 | #define lttng_poll_del(events, fd) \ |
| 122 | compat_epoll_del(events, fd) |
| 123 | |
| 124 | /* |
| 125 | * Set up the poll set limits variable poll_max_size |
| 126 | */ |
| 127 | extern void compat_epoll_set_max_size(void); |
| 128 | #define lttng_poll_set_max_size() \ |
| 129 | compat_epoll_set_max_size() |
| 130 | |
| 131 | /* |
| 132 | * This function memset with zero the structure since it can be reused at each |
| 133 | * round of a main loop. Being in a loop and using a non static number of fds, |
| 134 | * this function must be called to insure coherent events with associted fds. |
| 135 | */ |
| 136 | static inline void lttng_poll_reset(struct lttng_poll_event *events) |
| 137 | { |
| 138 | if (events && events->events) { |
| 139 | memset(events->events, 0, |
| 140 | events->nb_fd * sizeof(struct epoll_event)); |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Clean the events structure of a lttng_poll_event. It's the caller |
| 146 | * responsability to free the lttng_poll_event memory. |
| 147 | */ |
| 148 | static inline void lttng_poll_clean(struct lttng_poll_event *events) |
| 149 | { |
| 150 | int ret; |
| 151 | |
| 152 | if (events) { |
| 153 | ret = close(events->epfd); |
| 154 | if (ret) { |
| 155 | perror("close"); |
| 156 | } |
| 157 | __lttng_poll_free((void *) events->events); |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | #else /* HAVE_EPOLL */ |
| 162 | /* |
| 163 | * Fallback on poll(2) API |
| 164 | */ |
| 165 | |
| 166 | /* Needed for some poll event values */ |
| 167 | #ifndef __USE_XOPEN |
| 168 | #define __USE_XOPEN |
| 169 | #endif |
| 170 | |
| 171 | /* Needed for some poll event values */ |
| 172 | #ifndef __USE_GNU |
| 173 | #define __USE_GNU |
| 174 | #endif |
| 175 | |
| 176 | #include <poll.h> |
| 177 | #include <stdint.h> |
| 178 | |
| 179 | enum { |
| 180 | /* Polling variables compatibility for poll */ |
| 181 | LPOLLIN = POLLIN, |
| 182 | LPOLLPRI = POLLPRI, |
| 183 | LPOLLOUT = POLLOUT, |
| 184 | LPOLLRDNORM = POLLRDNORM, |
| 185 | LPOLLRDBAND = POLLRDBAND, |
| 186 | LPOLLWRNORM = POLLWRNORM, |
| 187 | LPOLLWRBAND = POLLWRBAND, |
| 188 | #if __linux__ |
| 189 | LPOLLMSG = POLLMSG, |
| 190 | LPOLLRDHUP = POLLRDHUP, |
| 191 | #elif defined(__FreeBSD__) |
| 192 | LPOLLMSG = 0, |
| 193 | LPOLLRDHUP = 0, |
| 194 | #else |
| 195 | #error "Please add support for your OS." |
| 196 | #endif /* __linux__ */ |
| 197 | LPOLLERR = POLLERR, |
| 198 | LPOLLHUP = POLLHUP | POLLNVAL, |
| 199 | /* Close on exec feature does not exist for poll(2) */ |
| 200 | LTTNG_CLOEXEC = 0xdead, |
| 201 | }; |
| 202 | |
| 203 | struct compat_poll_event { |
| 204 | uint32_t nb_fd; /* Current number of fd in events */ |
| 205 | uint32_t events_size; /* Size of events array */ |
| 206 | struct pollfd *events; |
| 207 | }; |
| 208 | #define lttng_poll_event compat_poll_event |
| 209 | |
| 210 | /* |
| 211 | * For the following calls, consider 'e' to be a lttng_poll_event pointer and i |
| 212 | * being the index of the events array. |
| 213 | */ |
| 214 | #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].fd |
| 215 | #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].revents |
| 216 | #define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd |
| 217 | #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size |
| 218 | |
| 219 | /* |
| 220 | * Create a pollfd structure of size 'size'. |
| 221 | */ |
| 222 | extern int compat_poll_create(struct lttng_poll_event *events, int size); |
| 223 | #define lttng_poll_create(events, size, flags) \ |
| 224 | compat_poll_create(events, size) |
| 225 | |
| 226 | /* |
| 227 | * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data |
| 228 | * structure. |
| 229 | */ |
| 230 | extern int compat_poll_wait(struct lttng_poll_event *events, int timeout); |
| 231 | #define lttng_poll_wait(events, timeout) \ |
| 232 | compat_poll_wait(events, timeout) |
| 233 | |
| 234 | /* |
| 235 | * Add the fd to the pollfd structure. Resize if needed. |
| 236 | */ |
| 237 | extern int compat_poll_add(struct lttng_poll_event *events, |
| 238 | int fd, uint32_t req_events); |
| 239 | #define lttng_poll_add(events, fd, req_events) \ |
| 240 | compat_poll_add(events, fd, req_events) |
| 241 | |
| 242 | /* |
| 243 | * Remove the fd from the pollfd. Memory allocation is done to recreate a new |
| 244 | * pollfd, data is copied from the old pollfd to the new and, finally, the old |
| 245 | * one is freed(). |
| 246 | */ |
| 247 | extern int compat_poll_del(struct lttng_poll_event *events, int fd); |
| 248 | #define lttng_poll_del(events, fd) \ |
| 249 | compat_poll_del(events, fd) |
| 250 | |
| 251 | /* |
| 252 | * Set up the poll set limits variable poll_max_size |
| 253 | */ |
| 254 | extern void compat_poll_set_max_size(void); |
| 255 | #define lttng_poll_set_max_size() \ |
| 256 | compat_poll_set_max_size() |
| 257 | |
| 258 | /* |
| 259 | * No need to reset a pollfd structure for poll(2) |
| 260 | */ |
| 261 | static inline void lttng_poll_reset(struct lttng_poll_event *events) |
| 262 | {} |
| 263 | |
| 264 | /* |
| 265 | * Clean the events structure of a lttng_poll_event. It's the caller |
| 266 | * responsability to free the lttng_poll_event memory. |
| 267 | */ |
| 268 | static inline void lttng_poll_clean(struct lttng_poll_event *events) |
| 269 | { |
| 270 | if (events) { |
| 271 | __lttng_poll_free((void *) events->events); |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | #endif /* HAVE_EPOLL */ |
| 276 | |
| 277 | #endif /* _LTT_POLL_H */ |