--- /dev/null
+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; only version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _LTT_POLL_H
+#define _LTT_POLL_H
+
+#include <string.h>
+#include <unistd.h>
+
+#include <lttng-share.h>
+
+/*
+ * Value taken from the hard limit allowed by the kernel when using setrlimit
+ * with RLIMIT_NOFILE on an Intel i7 CPU and Linux 3.0.3.
+ */
+#define LTTNG_POLL_DEFAULT_SIZE 65535
+
+/*
+ * Maximum number of fd we can monitor.
+ *
+ * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will
+ * be used for the maximum size of the poll set. If this interface is not
+ * available, according to the manpage, the max_user_watches value is 1/25 (4%)
+ * of the available low memory divided by the registration cost in bytes which
+ * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel.
+ *
+ * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by
+ * getrlimit(2).
+ */
+extern unsigned int poll_max_size;
+
+/*
+ * Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
+ */
+static inline void __lttng_poll_free(void *events)
+{
+ free(events);
+}
+
+/*
+ * epoll(7) implementation.
+ */
+#ifdef HAVE_EPOLL
+#include <sys/epoll.h>
+
+/* See man epoll(7) for this define path */
+#define LTTNG_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
+
+enum {
+ /* Polling variables compatibility for epoll */
+ LPOLLIN = EPOLLIN,
+ LPOLLPRI = EPOLLPRI,
+ LPOLLOUT = EPOLLOUT,
+ LPOLLRDNORM = EPOLLRDNORM,
+ LPOLLRDBAND = EPOLLRDBAND,
+ LPOLLWRNORM = EPOLLWRNORM,
+ LPOLLWRBAND = EPOLLWRBAND,
+ LPOLLMSG = EPOLLMSG,
+ LPOLLERR = EPOLLERR,
+ LPOLLHUP = EPOLLHUP,
+ LPOLLNVAL = EPOLLHUP,
+ LPOLLRDHUP = EPOLLRDHUP,
+ /* Close on exec feature of epoll */
+ LTTNG_CLOEXEC = EPOLL_CLOEXEC,
+};
+
+struct compat_epoll_event {
+ int epfd;
+ uint32_t nb_fd; /* Current number of fd in events */
+ uint32_t events_size; /* Size of events array */
+ struct epoll_event *events;
+};
+#define lttng_poll_event compat_epoll_event
+
+/*
+ * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
+ * being the index of the events array.
+ */
+#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
+#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
+#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
+#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
+
+/*
+ * Create the epoll set. No memory allocation is done here.
+ */
+extern int compat_epoll_create(struct lttng_poll_event *events,
+ int size, int flags);
+#define lttng_poll_create(events, size, flags) \
+ compat_epoll_create(events, size, flags);
+
+/*
+ * Wait on epoll set with the number of fd registered to the lttng_poll_event
+ * data structure (events).
+ */
+extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout);
+#define lttng_poll_wait(events, timeout) \
+ compat_epoll_wait(events, timeout);
+
+/*
+ * Add a fd to the epoll set and resize the epoll_event structure if needed.
+ */
+extern int compat_epoll_add(struct lttng_poll_event *events,
+ int fd, uint32_t req_events);
+#define lttng_poll_add(events, fd, req_events) \
+ compat_epoll_add(events, fd, req_events);
+
+/*
+ * Remove a fd from the epoll set.
+ */
+extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
+#define lttng_poll_del(events, fd) \
+ compat_epoll_del(events, fd);
+
+/*
+ * Set up the poll set limits variable poll_max_size
+ */
+extern void compat_epoll_set_max_size(void);
+#define lttng_poll_set_max_size(void) \
+ compat_epoll_set_max_size(void);
+
+/*
+ * This function memset with zero the structure since it can be reused at each
+ * round of a main loop. Being in a loop and using a non static number of fds,
+ * this function must be called to insure coherent events with associted fds.
+ */
+static inline void lttng_poll_reset(struct lttng_poll_event *events)
+{
+ if (events && events->events) {
+ memset(events->events, 0,
+ events->nb_fd * sizeof(struct epoll_event));
+ }
+}
+
+/*
+ * Clean the events structure of a lttng_poll_event. It's the caller
+ * responsability to free the lttng_poll_event memory.
+ */
+static inline void lttng_poll_clean(struct lttng_poll_event *events)
+{
+ if (events) {
+ close(events->epfd);
+ __lttng_poll_free((void *) events->events);
+ }
+}
+
+#else /* HAVE_EPOLL */
+/*
+ * Fallback on poll(2) API
+ */
+
+/* Needed for some poll event values */
+#ifndef __USE_XOPEN
+#define __USE_XOPEN
+#endif
+
+/* Needed for some poll event values */
+#ifndef __USE_GNU
+#define __USE_GNU
+#endif
+
+#include <poll.h>
+#include <stdint.h>
+
+enum {
+ /* Polling variables compatibility for poll */
+ LPOLLIN = POLLIN,
+ LPOLLPRI = POLLPRI,
+ LPOLLOUT = POLLOUT,
+ LPOLLRDNORM = POLLRDNORM,
+ LPOLLRDBAND = POLLRDBAND,
+ LPOLLWRNORM = POLLWRNORM,
+ LPOLLWRBAND = POLLWRBAND,
+ LPOLLMSG = POLLMSG,
+ LPOLLERR = POLLERR,
+ LPOLLHUP = POLLHUP | POLLNVAL,
+ LPOLLRDHUP = POLLRDHUP,
+ /* Close on exec feature does not exist for poll(2) */
+ LTTNG_CLOEXEC = 0xdead,
+};
+
+struct compat_poll_event {
+ uint32_t nb_fd; /* Current number of fd in events */
+ uint32_t events_size; /* Size of events array */
+ struct pollfd *events;
+};
+#define lttng_poll_event compat_poll_event
+
+/*
+ * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
+ * being the index of the events array.
+ */
+#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].fd
+#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].revents
+#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
+#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
+
+/*
+ * Create a pollfd structure of size 'size'.
+ */
+extern int compat_poll_create(struct lttng_poll_event *events, int size);
+#define lttng_poll_create(events, size, flags) \
+ compat_poll_create(events, size);
+
+/*
+ * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
+ * structure.
+ */
+extern int compat_poll_wait(struct lttng_poll_event *events, int timeout);
+#define lttng_poll_wait(events, timeout) \
+ compat_poll_wait(events, timeout);
+
+/*
+ * Add the fd to the pollfd structure. Resize if needed.
+ */
+extern int compat_poll_add(struct lttng_poll_event *events,
+ int fd, uint32_t req_events);
+#define lttng_poll_add(events, fd, req_events) \
+ compat_poll_add(events, fd, req_events);
+
+/*
+ * Remove the fd from the pollfd. Memory allocation is done to recreate a new
+ * pollfd, data is copied from the old pollfd to the new and, finally, the old
+ * one is freed().
+ */
+extern int compat_poll_del(struct lttng_poll_event *events, int fd);
+#define lttng_poll_del(events, fd) \
+ compat_poll_del(events, fd);
+
+/*
+ * Set up the poll set limits variable poll_max_size
+ */
+extern void compat_poll_set_max_size(void);
+#define lttng_poll_set_max_size(void) \
+ compat_poll_set_max_size(void);
+
+/*
+ * No need to reset a pollfd structure for poll(2)
+ */
+static inline void lttng_poll_reset(struct lttng_poll_event *events)
+{}
+
+/*
+ * Clean the events structure of a lttng_poll_event. It's the caller
+ * responsability to free the lttng_poll_event memory.
+ */
+static inline void lttng_poll_clean(struct lttng_poll_event *events)
+{
+ if (events) {
+ __lttng_poll_free((void *) events->events);
+ }
+}
+
+#endif /* HAVE_EPOLL */
+
+#endif /* _LTT_POLL_H */
projects / lttng-tools.git / blobdiff