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 <termios.h>
  31 #include <sys/ioctl.h>
  32
  33 #include "asterisk/io.h"
  34 #include "asterisk/utils.h"
  35
  36 #ifdef DEBUG_IO
  37 #define DEBUG DEBUG_M
  38 #else
  39 #define DEBUG(a)
  40 #endif
  41
  42 /*! \brief
  43  * Kept for each file descriptor
  44  */
  45 struct io_rec {
  46         ast_io_cb callback;             /*!< What is to be called */
  47         void *data;                     /*!< Data to be passed */
  48         int *id;                        /*!< ID number */
  49 };
  50
  51 /* These two arrays are keyed with
  52    the same index.  it's too bad that
  53    pollfd doesn't have a callback field
  54    or something like that.  They grow as
  55    needed, by GROW_SHRINK_SIZE structures
  56    at once */
  57
  58 #define GROW_SHRINK_SIZE 512
  59
  60 /*! \brief Global IO variables are now in a struct in order to be
  61    made threadsafe */
  62 struct io_context {
  63         struct pollfd *fds;           /*!< Poll structure */
  64         struct io_rec *ior;           /*!< Associated I/O records */
  65         unsigned int fdcnt;           /*!< First available fd */
  66         unsigned int maxfdcnt;        /*!< Maximum available fd */
  67         int current_ioc;              /*!< Currently used io callback */
  68         int needshrink;               /*!< Whether something has been deleted */
  69 };
  70
  71 /*! \brief Create an I/O context */
  72 struct io_context *io_context_create(void)
  73 {
  74         struct io_context *tmp = NULL;
  75
  76         if (!(tmp = ast_malloc(sizeof(*tmp))))
  77                 return NULL;
  78
  79         tmp->needshrink = 0;
  80         tmp->fdcnt = 0;
  81         tmp->maxfdcnt = GROW_SHRINK_SIZE/2;
  82         tmp->current_ioc = -1;
  83
  84         if (!(tmp->fds = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->fds)))) {
  85                 ast_free(tmp);
  86                 tmp = NULL;
  87         } else {
  88                 if (!(tmp->ior = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->ior)))) {
  89                         ast_free(tmp->fds);
  90                         ast_free(tmp);
  91                         tmp = NULL;
  92                 }
  93         }
  94
  95         return tmp;
  96 }
  97
  98 void io_context_destroy(struct io_context *ioc)
  99 {
 100         /* Free associated memory with an I/O context */
 101         if (ioc->fds)
 102                 ast_free(ioc->fds);
 103         if (ioc->ior)
 104                 ast_free(ioc->ior);
 105
 106         ast_free(ioc);
 107 }
 108
 109 /*! \brief
 110  * Grow the size of our arrays.
 111  * \return 0 on success or -1 on failure
 112  */
 113 static int io_grow(struct io_context *ioc)
 114 {
 115         void *tmp;
 116
 117         DEBUG(ast_debug(1, "io_grow()\n"));
 118
 119         ioc->maxfdcnt += GROW_SHRINK_SIZE;
 120
 121         if ((tmp = ast_realloc(ioc->ior, (ioc->maxfdcnt + 1) * sizeof(*ioc->ior)))) {
 122                 ioc->ior = tmp;
 123                 if ((tmp = ast_realloc(ioc->fds, (ioc->maxfdcnt + 1) * sizeof(*ioc->fds)))) {
 124                         ioc->fds = tmp;
 125                 } else {
 126                         /*
 127                          * Failed to allocate enough memory for the pollfd.  Not
 128                          * really any need to shrink back the iorec's as we'll
 129                          * probably want to grow them again soon when more memory
 130                          * is available, and then they'll already be the right size
 131                          */
 132                         ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 133                         return -1;
 134                 }
 135         } else {
 136                 /*
 137                  * Memory allocation failure.  We return to the old size, and
 138                  * return a failure
 139                  */
 140                 ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 141                 return -1;
 142         }
 143
 144         return 0;
 145 }
 146
 147 /*! \brief
 148  * Add a new I/O entry for this file descriptor
 149  * with the given event mask, to call callback with
 150  * data as an argument.
 151  * \return Returns NULL on failure.
 152  */
 153 int *ast_io_add(struct io_context *ioc, int fd, ast_io_cb callback, short events, void *data)
 154 {
 155         int *ret;
 156
 157         DEBUG(ast_debug(1, "ast_io_add()\n"));
 158
 159         if (ioc->fdcnt >= ioc->maxfdcnt) {
 160                 /*
 161                  * We don't have enough space for this entry.  We need to
 162                  * reallocate maxfdcnt poll fd's and io_rec's, or back out now.
 163                  */
 164                 if (io_grow(ioc))
 165                         return NULL;
 166         }
 167
 168         /*
 169          * At this point, we've got sufficiently large arrays going
 170          * and we can make an entry for it in the pollfd and io_r
 171          * structures.
 172          */
 173         ioc->fds[ioc->fdcnt].fd = fd;
 174         ioc->fds[ioc->fdcnt].events = events;
 175         ioc->fds[ioc->fdcnt].revents = 0;
 176         ioc->ior[ioc->fdcnt].callback = callback;
 177         ioc->ior[ioc->fdcnt].data = data;
 178
 179         if (!(ioc->ior[ioc->fdcnt].id = ast_malloc(sizeof(*ioc->ior[ioc->fdcnt].id)))) {
 180                 /* Bonk if we couldn't allocate an int */
 181                 return NULL;
 182         }
 183
 184         *(ioc->ior[ioc->fdcnt].id) = ioc->fdcnt;
 185         ret = ioc->ior[ioc->fdcnt].id;
 186         ioc->fdcnt++;
 187
 188         return ret;
 189 }
 190
 191 int *ast_io_change(struct io_context *ioc, int *id, int fd, ast_io_cb callback, short events, void *data)
 192 {
 193         /* If this id exceeds our file descriptor count it doesn't exist here */
 194         if (*id > ioc->fdcnt)
 195                 return NULL;
 196
 197         if (fd > -1)
 198                 ioc->fds[*id].fd = fd;
 199         if (callback)
 200                 ioc->ior[*id].callback = callback;
 201         if (events)
 202                 ioc->fds[*id].events = events;
 203         if (data)
 204                 ioc->ior[*id].data = data;
 205
 206         return id;
 207 }
 208
 209 static int io_shrink(struct io_context *ioc)
 210 {
 211         int getfrom, putto = 0;
 212
 213         /*
 214          * Bring the fields from the very last entry to cover over
 215          * the entry we are removing, then decrease the size of the
 216          * arrays by one.
 217          */
 218         for (getfrom = 0; getfrom < ioc->fdcnt; getfrom++) {
 219                 if (ioc->ior[getfrom].id) {
 220                         /* In use, save it */
 221                         if (getfrom != putto) {
 222                                 ioc->fds[putto] = ioc->fds[getfrom];
 223                                 ioc->ior[putto] = ioc->ior[getfrom];
 224                                 *(ioc->ior[putto].id) = putto;
 225                         }
 226                         putto++;
 227                 }
 228         }
 229         ioc->fdcnt = putto;
 230         ioc->needshrink = 0;
 231         /* FIXME: We should free some memory if we have lots of unused
 232            io structs */
 233         return 0;
 234 }
 235
 236 int ast_io_remove(struct io_context *ioc, int *_id)
 237 {
 238         int x;
 239
 240         if (!_id) {
 241                 ast_log(LOG_WARNING, "Asked to remove NULL?\n");
 242                 return -1;
 243         }
 244
 245         for (x = 0; x < ioc->fdcnt; x++) {
 246                 if (ioc->ior[x].id == _id) {
 247                         /* Free the int immediately and set to NULL so we know it's unused now */
 248                         ast_free(ioc->ior[x].id);
 249                         ioc->ior[x].id = NULL;
 250                         ioc->fds[x].events = 0;
 251                         ioc->fds[x].revents = 0;
 252                         ioc->needshrink = 1;
 253                         if (ioc->current_ioc == -1)
 254                                 io_shrink(ioc);
 255                         return 0;
 256                 }
 257         }
 258
 259         ast_log(LOG_NOTICE, "Unable to remove unknown id %p\n", _id);
 260
 261         return -1;
 262 }
 263
 264 /*! \brief
 265  * Make the poll call, and call
 266  * the callbacks for anything that needs
 267  * to be handled
 268  */
 269 int ast_io_wait(struct io_context *ioc, int howlong)
 270 {
 271         int res, x, origcnt;
 272
 273         DEBUG(ast_debug(1, "ast_io_wait()\n"));
 274
 275         if ((res = poll(ioc->fds, ioc->fdcnt, howlong)) <= 0)
 276                 return res;
 277
 278         /* At least one event tripped */
 279         origcnt = ioc->fdcnt;
 280         for (x = 0; x < origcnt; x++) {
 281                 /* Yes, it is possible for an entry to be deleted and still have an
 282                    event waiting if it occurs after the original calling id */
 283                 if (ioc->fds[x].revents && ioc->ior[x].id) {
 284                         /* There's an event waiting */
 285                         ioc->current_ioc = *ioc->ior[x].id;
 286                         if (ioc->ior[x].callback) {
 287                                 if (!ioc->ior[x].callback(ioc->ior[x].id, ioc->fds[x].fd, ioc->fds[x].revents, ioc->ior[x].data)) {
 288                                         /* Time to delete them since they returned a 0 */
 289                                         ast_io_remove(ioc, ioc->ior[x].id);
 290                                 }
 291                         }
 292                         ioc->current_ioc = -1;
 293                 }
 294         }
 295
 296         if (ioc->needshrink)
 297                 io_shrink(ioc);
 298
 299         return res;
 300 }
 301
 302 void ast_io_dump(struct io_context *ioc)
 303 {
 304         /*
 305          * Print some debugging information via
 306          * the logger interface
 307          */
 308         int x;
 309
 310         ast_debug(1, "Asterisk IO Dump: %d entries, %d max entries\n", ioc->fdcnt, ioc->maxfdcnt);
 311         ast_debug(1, "================================================\n");
 312         ast_debug(1, "| ID    FD     Callback    Data        Events  |\n");
 313         ast_debug(1, "+------+------+-----------+-----------+--------+\n");
 314         for (x = 0; x < ioc->fdcnt; x++) {
 315                 ast_debug(1, "| %.4d | %.4d | %p | %p | %.6x |\n",
 316                                 *ioc->ior[x].id,
 317                                 ioc->fds[x].fd,
 318                                 ioc->ior[x].callback,
 319                                 ioc->ior[x].data,
 320                                 ioc->fds[x].events);
 321         }
 322         ast_debug(1, "================================================\n");
 323 }
 324
 325 /* Unrelated I/O functions */
 326
 327 int ast_hide_password(int fd)
 328 {
 329         struct termios tios;
 330         int res;
 331         int old;
 332         if (!isatty(fd))
 333                 return -1;
 334         res = tcgetattr(fd, &tios);
 335         if (res < 0)
 336                 return -1;
 337         old = tios.c_lflag & (ECHO | ECHONL);
 338         tios.c_lflag &= ~ECHO;
 339         tios.c_lflag |= ECHONL;
 340         res = tcsetattr(fd, TCSAFLUSH, &tios);
 341         if (res < 0)
 342                 return -1;
 343         return old;
 344 }
 345
 346 int ast_restore_tty(int fd, int oldstate)
 347 {
 348         int res;
 349         struct termios tios;
 350         if (oldstate < 0)
 351                 return 0;
 352         res = tcgetattr(fd, &tios);
 353         if (res < 0)
 354                 return -1;
 355         tios.c_lflag &= ~(ECHO | ECHONL);
 356         tios.c_lflag |= oldstate;
 357         res = tcsetattr(fd, TCSAFLUSH, &tios);
 358         if (res < 0)
 359                 return -1;
 360         return 0;
 361 }
 362
 363 int ast_get_termcols(int fd)
 364 {
 365         struct winsize win;
 366         int cols = 0;
 367
 368         if (!isatty(fd))
 369                 return -1;
 370
 371         if ( ioctl(fd, TIOCGWINSZ, &win) != -1 ) {
 372                 if ( !cols && win.ws_col > 0 )
 373                         cols = (int) win.ws_col;
 374         } else {
 375                 /* assume 80 characters if the ioctl fails for some reason */
 376                 cols = 80;
 377         }
 378
 379         return cols;
 380 }
 381