| 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 |
| 5 | * it under the terms of the GNU General Public License, version 2 only, |
| 6 | * as published by the Free Software Foundation. |
| 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 |
| 14 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 16 | */ |
| 17 | |
| 18 | #define _GNU_SOURCE |
| 19 | #include <stdlib.h> |
| 20 | #include <sys/resource.h> |
| 21 | #include <sys/time.h> |
| 22 | |
| 23 | #include <common/defaults.h> |
| 24 | #include <common/error.h> |
| 25 | |
| 26 | #include "poll.h" |
| 27 | |
| 28 | unsigned int poll_max_size; |
| 29 | |
| 30 | /* |
| 31 | * Create pollfd data structure. |
| 32 | */ |
| 33 | int compat_poll_create(struct lttng_poll_event *events, int size) |
| 34 | { |
| 35 | if (events == NULL || size <= 0) { |
| 36 | ERR("Wrong arguments for poll create"); |
| 37 | goto error; |
| 38 | } |
| 39 | |
| 40 | /* Don't bust the limit here */ |
| 41 | if (size > poll_max_size) { |
| 42 | size = poll_max_size; |
| 43 | } |
| 44 | |
| 45 | /* This *must* be freed by using lttng_poll_free() */ |
| 46 | events->events = zmalloc(size * sizeof(struct pollfd)); |
| 47 | if (events->events == NULL) { |
| 48 | perror("zmalloc struct pollfd"); |
| 49 | goto error; |
| 50 | } |
| 51 | |
| 52 | events->events_size = size; |
| 53 | events->nb_fd = 0; |
| 54 | |
| 55 | return 0; |
| 56 | |
| 57 | error: |
| 58 | return -1; |
| 59 | } |
| 60 | |
| 61 | /* |
| 62 | * Add fd to pollfd data structure with requested events. |
| 63 | */ |
| 64 | int compat_poll_add(struct lttng_poll_event *events, int fd, |
| 65 | uint32_t req_events) |
| 66 | { |
| 67 | int new_size; |
| 68 | struct pollfd *ptr; |
| 69 | |
| 70 | if (events == NULL || events->events == NULL || fd < 0) { |
| 71 | ERR("Bad compat poll add arguments"); |
| 72 | goto error; |
| 73 | } |
| 74 | |
| 75 | /* Reallocate pollfd structure by a factor of 2 if needed. */ |
| 76 | if (events->nb_fd >= events->events_size) { |
| 77 | new_size = 2 * events->events_size; |
| 78 | ptr = realloc(events->events, new_size * sizeof(struct pollfd)); |
| 79 | if (ptr == NULL) { |
| 80 | perror("realloc poll add"); |
| 81 | goto error; |
| 82 | } |
| 83 | events->events = ptr; |
| 84 | events->events_size = new_size; |
| 85 | } |
| 86 | |
| 87 | events->events[events->nb_fd].fd = fd; |
| 88 | events->events[events->nb_fd].events = req_events; |
| 89 | events->nb_fd++; |
| 90 | |
| 91 | DBG("fd %d of %d added to pollfd", fd, events->nb_fd); |
| 92 | |
| 93 | return 0; |
| 94 | |
| 95 | error: |
| 96 | return -1; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * Remove a fd from the pollfd structure. |
| 101 | */ |
| 102 | int compat_poll_del(struct lttng_poll_event *events, int fd) |
| 103 | { |
| 104 | int new_size, i, count = 0; |
| 105 | struct pollfd *old = NULL, *new = NULL; |
| 106 | |
| 107 | if (events == NULL || events->events == NULL || fd < 0) { |
| 108 | ERR("Wrong arguments for poll del"); |
| 109 | goto error; |
| 110 | } |
| 111 | |
| 112 | old = events->events; |
| 113 | new_size = events->events_size - 1; |
| 114 | |
| 115 | /* Safety check on size */ |
| 116 | if (new_size > poll_max_size) { |
| 117 | new_size = poll_max_size; |
| 118 | } |
| 119 | |
| 120 | new = zmalloc(new_size * sizeof(struct pollfd)); |
| 121 | if (new == NULL) { |
| 122 | perror("zmalloc poll del"); |
| 123 | goto error; |
| 124 | } |
| 125 | |
| 126 | for (i = 0; i < events->events_size; i++) { |
| 127 | /* Don't put back the fd we want to delete */ |
| 128 | if (old[i].fd != fd) { |
| 129 | new[count].fd = old[i].fd; |
| 130 | new[count].events = old[i].events; |
| 131 | count++; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | events->events_size = new_size; |
| 136 | events->events = new; |
| 137 | events->nb_fd--; |
| 138 | |
| 139 | free(old); |
| 140 | |
| 141 | return 0; |
| 142 | |
| 143 | error: |
| 144 | return -1; |
| 145 | } |
| 146 | |
| 147 | /* |
| 148 | * Wait on poll() with timeout. Blocking call. |
| 149 | */ |
| 150 | int compat_poll_wait(struct lttng_poll_event *events, int timeout) |
| 151 | { |
| 152 | int ret; |
| 153 | |
| 154 | if (events == NULL || events->events == NULL || |
| 155 | events->events_size < events->nb_fd) { |
| 156 | ERR("poll wait arguments error"); |
| 157 | goto error; |
| 158 | } |
| 159 | |
| 160 | ret = poll(events->events, events->nb_fd, timeout); |
| 161 | if (ret < 0) { |
| 162 | /* At this point, every error is fatal */ |
| 163 | perror("poll wait"); |
| 164 | goto error; |
| 165 | } |
| 166 | |
| 167 | return ret; |
| 168 | |
| 169 | error: |
| 170 | return -1; |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Setup poll set maximum size. |
| 175 | */ |
| 176 | void compat_poll_set_max_size(void) |
| 177 | { |
| 178 | int ret; |
| 179 | struct rlimit lim; |
| 180 | |
| 181 | /* Default value */ |
| 182 | poll_max_size = DEFAULT_POLL_SIZE; |
| 183 | |
| 184 | ret = getrlimit(RLIMIT_NOFILE, &lim); |
| 185 | if (ret < 0) { |
| 186 | perror("getrlimit poll RLIMIT_NOFILE"); |
| 187 | return; |
| 188 | } |
| 189 | |
| 190 | poll_max_size = lim.rlim_cur; |
| 191 | if (poll_max_size <= 0) { |
| 192 | /* Extra precaution */ |
| 193 | poll_max_size = DEFAULT_POLL_SIZE; |
| 194 | } |
| 195 | |
| 196 | DBG("poll set max size set to %u", poll_max_size); |
| 197 | } |