io.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief I/O Managment (Derived from Cheops-NG)
 *
 * \author Mark Spencer <[email protected]>
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <termios.h>
#include <sys/ioctl.h>

#include "asterisk/io.h"
#include "asterisk/utils.h"
#ifdef HAVE_SYSTEMD
#include <systemd/sd-daemon.h>

#ifndef SD_LISTEN_FDS_START
#define SD_LISTEN_FDS_START 3
#endif
#endif

#ifdef DEBUG_IO
#define DEBUG DEBUG_M
#else
#define DEBUG(a)
#endif

/*! \brief
 * Kept for each file descriptor
 */
struct io_rec {
 ast_io_cb callback; /*!< What is to be called */
 void *data; /*!< Data to be passed */
 int *id; /*!< ID number */
};

/* These two arrays are keyed with
 the same index. it's too bad that
 pollfd doesn't have a callback field
 or something like that. They grow as
 needed, by GROW_SHRINK_SIZE structures
 at once */

#define GROW_SHRINK_SIZE 512

/*! \brief Global IO variables are now in a struct in order to be
 made threadsafe */
struct io_context {
 struct pollfd *fds; /*!< Poll structure */
 struct io_rec *ior; /*!< Associated I/O records */
 unsigned int fdcnt; /*!< First available fd */
 unsigned int maxfdcnt; /*!< Maximum available fd */
 int current_ioc; /*!< Currently used io callback */
 int needshrink; /*!< Whether something has been deleted */
};

/*! \brief Create an I/O context */
struct io_context *io_context_create(void)
{
 struct io_context *tmp = NULL;

 if (!(tmp = ast_malloc(sizeof(*tmp))))
 return NULL;

 tmp->needshrink = 0;
 tmp->fdcnt = 0;
 tmp->maxfdcnt = GROW_SHRINK_SIZE/2;
 tmp->current_ioc = -1;

 if (!(tmp->fds = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->fds)))) {
 ast_free(tmp);
 tmp = NULL;
 } else {
 if (!(tmp->ior = ast_calloc(1, (GROW_SHRINK_SIZE / 2) * sizeof(*tmp->ior)))) {
 ast_free(tmp->fds);
 ast_free(tmp);
 tmp = NULL;
 }
 }

 return tmp;
}

void io_context_destroy(struct io_context *ioc)
{
 /* Free associated memory with an I/O context */
 if (ioc->fds)
 ast_free(ioc->fds);
 if (ioc->ior)
 ast_free(ioc->ior);

 ast_free(ioc);
}

/*! \brief
 * Grow the size of our arrays.
 * \return 0 on success or -1 on failure
 */
static int io_grow(struct io_context *ioc)
{
 void *tmp;

 DEBUG(ast_debug(1, "io_grow()\n"));

 ioc->maxfdcnt += GROW_SHRINK_SIZE;

 if ((tmp = ast_realloc(ioc->ior, (ioc->maxfdcnt + 1) * sizeof(*ioc->ior)))) {
 ioc->ior = tmp;
 if ((tmp = ast_realloc(ioc->fds, (ioc->maxfdcnt + 1) * sizeof(*ioc->fds)))) {
 ioc->fds = tmp;
 } else {
 /*
 * Failed to allocate enough memory for the pollfd. Not
 * really any need to shrink back the iorec's as we'll
 * probably want to grow them again soon when more memory
 * is available, and then they'll already be the right size
 */
 ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 return -1;
 }
 } else {
 /*
 * Memory allocation failure. We return to the old size, and
 * return a failure
 */
 ioc->maxfdcnt -= GROW_SHRINK_SIZE;
 return -1;
 }

 return 0;
}

/*! \brief
 * Add a new I/O entry for this file descriptor
 * with the given event mask, to call callback with
 * data as an argument.
 * \return Returns NULL on failure.
 */
int *ast_io_add(struct io_context *ioc, int fd, ast_io_cb callback, short events, void *data)
{
 int *ret;

 DEBUG(ast_debug(1, "ast_io_add()\n"));

 if (ioc->fdcnt >= ioc->maxfdcnt) {
 /*
 * We don't have enough space for this entry. We need to
 * reallocate maxfdcnt poll fd's and io_rec's, or back out now.
 */
 if (io_grow(ioc))
 return NULL;
 }

 /*
 * At this point, we've got sufficiently large arrays going
 * and we can make an entry for it in the pollfd and io_r
 * structures.
 */
 ioc->fds[ioc->fdcnt].fd = fd;
 ioc->fds[ioc->fdcnt].events = events;
 ioc->fds[ioc->fdcnt].revents = 0;
 ioc->ior[ioc->fdcnt].callback = callback;
 ioc->ior[ioc->fdcnt].data = data;

 if (!(ioc->ior[ioc->fdcnt].id = ast_malloc(sizeof(*ioc->ior[ioc->fdcnt].id)))) {
 /* Bonk if we couldn't allocate an int */
 return NULL;
 }

 *(ioc->ior[ioc->fdcnt].id) = ioc->fdcnt;
 ret = ioc->ior[ioc->fdcnt].id;
 ioc->fdcnt++;

 return ret;
}

int *ast_io_change(struct io_context *ioc, int *id, int fd, ast_io_cb callback, short events, void *data)
{
 /* If this id exceeds our file descriptor count it doesn't exist here */
 if (*id > ioc->fdcnt)
 return NULL;

 if (fd > -1)
 ioc->fds[*id].fd = fd;
 if (callback)
 ioc->ior[*id].callback = callback;
 if (events)
 ioc->fds[*id].events = events;
 if (data)
 ioc->ior[*id].data = data;

 return id;
}

static int io_shrink(struct io_context *ioc)
{
 int getfrom, putto = 0;

 /*
 * Bring the fields from the very last entry to cover over
 * the entry we are removing, then decrease the size of the
 * arrays by one.
 */
 for (getfrom = 0; getfrom < ioc->fdcnt; getfrom++) {
 if (ioc->ior[getfrom].id) {
 /* In use, save it */
 if (getfrom != putto) {
 ioc->fds[putto] = ioc->fds[getfrom];
 ioc->ior[putto] = ioc->ior[getfrom];
 *(ioc->ior[putto].id) = putto;
 }
 putto++;
 }
 }
 ioc->fdcnt = putto;
 ioc->needshrink = 0;
 /* FIXME: We should free some memory if we have lots of unused
 io structs */
 return 0;
}

int ast_io_remove(struct io_context *ioc, int *_id)
{
 int x;

 if (!_id) {
 ast_log(LOG_WARNING, "Asked to remove NULL?\n");
 return -1;
 }

 for (x = 0; x < ioc->fdcnt; x++) {
 if (ioc->ior[x].id == _id) {
 /* Free the int immediately and set to NULL so we know it's unused now */
 ast_free(ioc->ior[x].id);
 ioc->ior[x].id = NULL;
 ioc->fds[x].events = 0;
 ioc->fds[x].revents = 0;
 ioc->needshrink = 1;
 if (ioc->current_ioc == -1)
 io_shrink(ioc);
 return 0;
 }
 }

 ast_log(LOG_NOTICE, "Unable to remove unknown id %p\n", _id);

 return -1;
}

/*! \brief
 * Make the poll call, and call
 * the callbacks for anything that needs
 * to be handled
 */
int ast_io_wait(struct io_context *ioc, int howlong)
{
 int res, x, origcnt;

 DEBUG(ast_debug(1, "ast_io_wait()\n"));

 if ((res = ast_poll(ioc->fds, ioc->fdcnt, howlong)) <= 0) {
 return res;
 }

 /* At least one event tripped */
 origcnt = ioc->fdcnt;
 for (x = 0; x < origcnt; x++) {
 /* Yes, it is possible for an entry to be deleted and still have an
 event waiting if it occurs after the original calling id */
 if (ioc->fds[x].revents && ioc->ior[x].id) {
 /* There's an event waiting */
 ioc->current_ioc = *ioc->ior[x].id;
 if (ioc->ior[x].callback) {
 if (!ioc->ior[x].callback(ioc->ior[x].id, ioc->fds[x].fd, ioc->fds[x].revents, ioc->ior[x].data)) {
 /* Time to delete them since they returned a 0 */
 ast_io_remove(ioc, ioc->ior[x].id);
 }
 }
 ioc->current_ioc = -1;
 }
 }

 if (ioc->needshrink)
 io_shrink(ioc);

 return res;
}

void ast_io_dump(struct io_context *ioc)
{
 /*
 * Print some debugging information via
 * the logger interface
 */
 int x;

 ast_debug(1, "Asterisk IO Dump: %u entries, %u max entries\n", ioc->fdcnt, ioc->maxfdcnt);
 ast_debug(1, "================================================\n");
 ast_debug(1, "| ID FD Callback Data Events |\n");
 ast_debug(1, "+------+------+-----------+-----------+--------+\n");
 for (x = 0; x < ioc->fdcnt; x++) {
 ast_debug(1, "| %.4d | %.4d | %p | %p | %.6x |\n",
 *ioc->ior[x].id,
 ioc->fds[x].fd,
 ioc->ior[x].callback,
 ioc->ior[x].data,
 (unsigned)ioc->fds[x].events);
 }
 ast_debug(1, "================================================\n");
}

/* Unrelated I/O functions */

int ast_hide_password(int fd)
{
 struct termios tios;
 int res;
 int old;
 if (!isatty(fd))
 return -1;
 res = tcgetattr(fd, &tios);
 if (res < 0)
 return -1;
 old = tios.c_lflag & (ECHO | ECHONL);
 tios.c_lflag &= ~ECHO;
 tios.c_lflag |= ECHONL;
 res = tcsetattr(fd, TCSAFLUSH, &tios);
 if (res < 0)
 return -1;
 return old;
}

int ast_restore_tty(int fd, int oldstate)
{
 int res;
 struct termios tios;
 if (oldstate < 0)
 return 0;
 res = tcgetattr(fd, &tios);
 if (res < 0)
 return -1;
 tios.c_lflag &= ~(ECHO | ECHONL);
 tios.c_lflag |= oldstate;
 res = tcsetattr(fd, TCSAFLUSH, &tios);
 if (res < 0)
 return -1;
 return 0;
}

int ast_get_termcols(int fd)
{
 struct winsize win;
 int cols = 0;

 if (!isatty(fd))
 return -1;

 if ( ioctl(fd, TIOCGWINSZ, &win) != -1 ) {
 if ( !cols && win.ws_col > 0 )
 cols = (int) win.ws_col;
 } else {
 /* assume 80 characters if the ioctl fails for some reason */
 cols = 80;
 }

 return cols;
}

int ast_sd_notify(const char *state) {
#ifdef HAVE_SYSTEMD
 return sd_notify(0, state);
#else
 return 0;
#endif
}

/*!
 * \internal \brief Check the type and sockaddr of a file descriptor.
 * \param fd File Descriptor to check.
 * \param type SOCK_STREAM or SOCK_DGRAM
 * \param addr The socket address to match.
 * \retval 0 if matching
 * \retval -1 if not matching
 */
#ifdef HAVE_SYSTEMD
static int ast_sd_is_socket_sockaddr(int fd, int type, const struct ast_sockaddr* addr)
{
 int canretry = 1;
 struct ast_sockaddr fd_addr;
 struct sockaddr ss;
 socklen_t ss_len;

 if (sd_is_socket(fd, AF_UNSPEC, type, 1) <= 0) {
 return -1;
 }

doretry:
 if (getsockname(fd, &ss, &ss_len) != 0) {
 return -1;
 }

 if (ss.sa_family == AF_UNSPEC && canretry) {
 /* An unknown bug can cause silent failure from
 * the first call to getsockname. */
 canretry = 0;
 goto doretry;
 }

 ast_sockaddr_copy_sockaddr(&fd_addr, &ss, ss_len);

 return ast_sockaddr_cmp(addr, &fd_addr);
}
#endif

int ast_sd_get_fd(int type, const struct ast_sockaddr *addr)
{
#ifdef HAVE_SYSTEMD
 int count = sd_listen_fds(0);
 int idx;

 for (idx = 0; idx < count; idx++) {
 if (!ast_sd_is_socket_sockaddr(idx + SD_LISTEN_FDS_START, type, addr)) {
 return idx + SD_LISTEN_FDS_START;
 }
 }
#endif

 return -1;
}

int ast_sd_get_fd_un(int type, const char *path)
{
#ifdef HAVE_SYSTEMD
 int count = sd_listen_fds(0);
 int idx;

 for (idx = 0; idx < count; idx++) {
 if (sd_is_socket_unix(idx + SD_LISTEN_FDS_START, type, 1, path, 0) > 0) {
 return idx + SD_LISTEN_FDS_START;
 }
 }
#endif

 return -1;
}