main/io.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2005, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief I/O Managment (Derived from Cheops-NG)
  22  *
  23  * \author Mark Spencer <markster@digium.com>
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include <stdio.h>
  31 #include <unistd.h>
  32 #include <stdlib.h>
  33 #include <termios.h>
  34 #include <string.h>
  35 #include <sys/ioctl.h>
  36
  37 #include "asterisk/io.h"
  38 #include "asterisk/logger.h"
  39 #include "asterisk/utils.h"
  40
  41 #ifdef DEBUG_IO
  42 #define DEBUG DEBUG_M
  43 #else
  44 #define DEBUG(a)
  45 #endif
  46
  47 /*
  48  * Kept for each file descriptor
  49  */
  50 struct io_rec {
  51         ast_io_cb callback;             /* What is to be called */
  52         void *data;                             /* Data to be passed */
  53         int *id;                                        /* ID number */
  54 };
  55
  56 /* These two arrays are keyed with
  57    the same index.  it's too bad that
  58    pollfd doesn't have a callback field
  59    or something like that.  They grow as
  60    needed, by GROW_SHRINK_SIZE structures
  61    at once */
  62
  63 #define GROW_SHRINK_SIZE 512
  64
  65 /* Global variables are now in a struct in order to be
  66    made threadsafe */
  67 struct io_context {
  68         /* Poll structure */
  69         struct pollfd *fds;
  70         /* Associated I/O records */
  71         struct io_rec *ior;
  72         /* First available fd */
  73         unsigned int fdcnt;
  74         /* Maximum available fd */
  75         unsigned int maxfdcnt;
  76         /* Currently used io callback */
  77         int current_ioc;
  78         /* Whether something has been deleted */
  79         int needshrink;
  80 };
  81
  82 struct io_context *io_context_create(void)
  83 {
  84         /* Create an I/O context */
  85         struct io_context *tmp;
  86         if ((tmp = ast_malloc(sizeof(*tmp)))) {
  87                 tmp->needshrink = 0;
  88                 tmp->fdcnt = 0;
  89                 tmp->maxfdcnt = GROW_SHRINK_SIZE/2;
  90                 tmp->current_ioc = -1;
  91                 if (!(tmp->fds = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->fds)))) {
  92                         free(tmp);
  93                         tmp = NULL;
  94                 } else {
  95                         if (!(tmp->ior = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->ior)))) {
  96                                 free(tmp->fds);
  97                                 free(tmp);
  98                                 tmp = NULL;
  99                         }
 100                 }
 101         }
 102         return tmp;
 103 }
 104
 105 void io_context_destroy(struct io_context *ioc)
 106 {
 107         /* Free associated memory with an I/O context */
 108         if (ioc->fds)
 109                 free(ioc->fds);
 110         if (ioc->ior)
 111                 free(ioc->ior);
 112         free(ioc);
 113 }
 114
 115 static int io_grow(struct io_context *ioc)
 116 {
 117         /*
 118          * Grow the size of our arrays.  Return 0 on success or
 119          * -1 on failure
 120          */
 121         void *tmp;
 122         DEBUG(ast_log(LOG_DEBUG, "io_grow()\n"));
 123         ioc->maxfdcnt += GROW_SHRINK_SIZE;
 124         if ((tmp = ast_realloc(ioc->ior, (ioc->maxfdcnt + 1) * sizeof(*ioc->ior)))) {
 125                 ioc->ior = tmp;
 126                 if ((tmp = ast_realloc(ioc->fds, (ioc->maxfdcnt + 1) * sizeof(*ioc->fds)))) {
 127                         ioc->fds = tmp;
 128                 } else {
 129                         /*
 130                          * Failed to allocate enough memory for the pollfd.  Not
 131                          * really any need to shrink back the iorec's as we'll
 132                          * probably want to grow them again soon when more memory
 133                          * is available, and then they'll already be the right size
 134                          */
 135                         ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 136                         return -1;
 137                 }
 138         } else {
 139                 /*
 140                  * Memory allocation failure.  We return to the old size, and
 141                  * return a failure
 142                  */
 143                 ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 144                 return -1;
 145         }
 146         return 0;
 147 }
 148
 149 int *ast_io_add(struct io_context *ioc, int fd, ast_io_cb callback, short events, void *data)
 150 {
 151         /*
 152          * Add a new I/O entry for this file descriptor
 153          * with the given event mask, to call callback with
 154          * data as an argument.  Returns NULL on failure.
 155          */
 156         int *ret;
 157         DEBUG(ast_log(LOG_DEBUG, "ast_io_add()\n"));
 158         if (ioc->fdcnt >= ioc->maxfdcnt) {
 159                 /*
 160                  * We don't have enough space for this entry.  We need to
 161                  * reallocate maxfdcnt poll fd's and io_rec's, or back out now.
 162                  */
 163                 if (io_grow(ioc))
 164                         return NULL;
 165         }
 166
 167         /*
 168          * At this point, we've got sufficiently large arrays going
 169          * and we can make an entry for it in the pollfd and io_r
 170          * structures.
 171          */
 172         ioc->fds[ioc->fdcnt].fd = fd;
 173         ioc->fds[ioc->fdcnt].events = events;
 174         ioc->fds[ioc->fdcnt].revents = 0;
 175         ioc->ior[ioc->fdcnt].callback = callback;
 176         ioc->ior[ioc->fdcnt].data = data;
 177         if (!(ioc->ior[ioc->fdcnt].id = ast_malloc(sizeof(*ioc->ior[ioc->fdcnt].id)))) {
 178                 /* Bonk if we couldn't allocate an int */
 179                 return NULL;
 180         }
 181         *(ioc->ior[ioc->fdcnt].id) = ioc->fdcnt;
 182         ret = ioc->ior[ioc->fdcnt].id;
 183         ioc->fdcnt++;
 184         return ret;
 185 }
 186
 187 int *ast_io_change(struct io_context *ioc, int *id, int fd, ast_io_cb callback, short events, void *data)
 188 {
 189         if (*id < ioc->fdcnt) {
 190                 if (fd > -1)
 191                         ioc->fds[*id].fd = fd;
 192                 if (callback)
 193                         ioc->ior[*id].callback = callback;
 194                 if (events)
 195                         ioc->fds[*id].events = events;
 196                 if (data)
 197                         ioc->ior[*id].data = data;
 198                 return id;
 199         }
 200         return NULL;
 201 }
 202
 203 static int io_shrink(struct io_context *ioc)
 204 {
 205         int getfrom;
 206         int putto = 0;
 207         /*
 208          * Bring the fields from the very last entry to cover over
 209          * the entry we are removing, then decrease the size of the
 210          * arrays by one.
 211          */
 212         for (getfrom = 0; getfrom < ioc->fdcnt; getfrom++) {
 213                 if (ioc->ior[getfrom].id) {
 214                         /* In use, save it */
 215                         if (getfrom != putto) {
 216                                 ioc->fds[putto] = ioc->fds[getfrom];
 217                                 ioc->ior[putto] = ioc->ior[getfrom];
 218                                 *(ioc->ior[putto].id) = putto;
 219                         }
 220                         putto++;
 221                 }
 222         }
 223         ioc->fdcnt = putto;
 224         ioc->needshrink = 0;
 225         /* FIXME: We should free some memory if we have lots of unused
 226            io structs */
 227         return 0;
 228 }
 229
 230 int ast_io_remove(struct io_context *ioc, int *_id)
 231 {
 232         int x;
 233         if (!_id) {
 234                 ast_log(LOG_WARNING, "Asked to remove NULL?\n");
 235                 return -1;
 236         }
 237         for (x = 0; x < ioc->fdcnt; x++) {
 238                 if (ioc->ior[x].id == _id) {
 239                         /* Free the int immediately and set to NULL so we know it's unused now */
 240                         free(ioc->ior[x].id);
 241                         ioc->ior[x].id = NULL;
 242                         ioc->fds[x].events = 0;
 243                         ioc->fds[x].revents = 0;
 244                         ioc->needshrink = 1;
 245                         if (ioc->current_ioc == -1)
 246                                 io_shrink(ioc);
 247                         return 0;
 248                 }
 249         }
 250
 251         ast_log(LOG_NOTICE, "Unable to remove unknown id %p\n", _id);
 252         return -1;
 253 }
 254
 255 int ast_io_wait(struct io_context *ioc, int howlong)
 256 {
 257         /*
 258          * Make the poll call, and call
 259          * the callbacks for anything that needs
 260          * to be handled
 261          */
 262         int res;
 263         int x;
 264         int origcnt;
 265         DEBUG(ast_log(LOG_DEBUG, "ast_io_wait()\n"));
 266         res = poll(ioc->fds, ioc->fdcnt, howlong);
 267         if (res > 0) {
 268                 /*
 269                  * At least one event
 270                  */
 271                 origcnt = ioc->fdcnt;
 272                 for(x = 0; x < origcnt; x++) {
 273                         /* Yes, it is possible for an entry to be deleted and still have an
 274                            event waiting if it occurs after the original calling id */
 275                         if (ioc->fds[x].revents && ioc->ior[x].id) {
 276                                 /* There's an event waiting */
 277                                 ioc->current_ioc = *ioc->ior[x].id;
 278                                 if (ioc->ior[x].callback) {
 279                                         if (!ioc->ior[x].callback(ioc->ior[x].id, ioc->fds[x].fd, ioc->fds[x].revents, ioc->ior[x].data)) {
 280                                                 /* Time to delete them since they returned a 0 */
 281                                                 ast_io_remove(ioc, ioc->ior[x].id);
 282                                         }
 283                                 }
 284                                 ioc->current_ioc = -1;
 285                         }
 286                 }
 287                 if (ioc->needshrink)
 288                         io_shrink(ioc);
 289         }
 290         return res;
 291 }
 292
 293 void ast_io_dump(struct io_context *ioc)
 294 {
 295         /*
 296          * Print some debugging information via
 297          * the logger interface
 298          */
 299         int x;
 300         ast_log(LOG_DEBUG, "Asterisk IO Dump: %d entries, %d max entries\n", ioc->fdcnt, ioc->maxfdcnt);
 301         ast_log(LOG_DEBUG, "================================================\n");
 302         ast_log(LOG_DEBUG, "| ID    FD     Callback    Data        Events  |\n");
 303         ast_log(LOG_DEBUG, "+------+------+-----------+-----------+--------+\n");
 304         for (x = 0; x < ioc->fdcnt; x++) {
 305                 ast_log(LOG_DEBUG, "| %.4d | %.4d | %p | %p | %.6x |\n",
 306                                 *ioc->ior[x].id,
 307                                 ioc->fds[x].fd,
 308                                 ioc->ior[x].callback,
 309                                 ioc->ior[x].data,
 310                                 ioc->fds[x].events);
 311         }
 312         ast_log(LOG_DEBUG, "================================================\n");
 313 }
 314
 315 /* Unrelated I/O functions */
 316
 317 int ast_hide_password(int fd)
 318 {
 319         struct termios tios;
 320         int res;
 321         int old;
 322         if (!isatty(fd))
 323                 return -1;
 324         res = tcgetattr(fd, &tios);
 325         if (res < 0)
 326                 return -1;
 327         old = tios.c_lflag & (ECHO | ECHONL);
 328         tios.c_lflag &= ~ECHO;
 329         tios.c_lflag |= ECHONL;
 330         res = tcsetattr(fd, TCSAFLUSH, &tios);
 331         if (res < 0)
 332                 return -1;
 333         return old;
 334 }
 335
 336 int ast_restore_tty(int fd, int oldstate)
 337 {
 338         int res;
 339         struct termios tios;
 340         if (oldstate < 0)
 341                 return 0;
 342         res = tcgetattr(fd, &tios);
 343         if (res < 0)
 344                 return -1;
 345         tios.c_lflag &= ~(ECHO | ECHONL);
 346         tios.c_lflag |= oldstate;
 347         res = tcsetattr(fd, TCSAFLUSH, &tios);
 348         if (res < 0)
 349                 return -1;
 350         return 0;
 351 }
 352
 353 int ast_get_termcols(int fd)
 354 {
 355         struct winsize win;
 356         int cols = 0;
 357
 358         if (!isatty(fd))
 359                 return -1;
 360
 361         if ( ioctl(fd, TIOCGWINSZ, &win) != -1 ) {
 362                 if ( !cols && win.ws_col > 0 )
 363                         cols = (int) win.ws_col;
 364         } else {
 365                 /* assume 80 characters if the ioctl fails for some reason */
 366                 cols = 80;
 367         }
 368
 369         return cols;
 370 }
 371