Mon Apr 30 07:36:34 2007

Asterisk developer's documentation

---

file.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * 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 Generic File Format Support.
 *
 * \author Mark Spencer <markster@digium.com> 
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "asterisk/frame.h"
#include "asterisk/file.h"
#include "asterisk/cli.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/sched.h"
#include "asterisk/options.h"
#include "asterisk/translate.h"
#include "asterisk/utils.h"
#include "asterisk/lock.h"
#include "asterisk/app.h"
#include "asterisk/pbx.h"
#include "asterisk/linkedlists.h"
#include "asterisk/module.h"

/*
 * The following variable controls the layout of localized sound files.
 * If 0, use the historical layout with prefix just before the filename
 * (i.e. digits/en/1.gsm , digits/it/1.gsm or default to digits/1.gsm),
 * if 1 put the prefix at the beginning of the filename
 * (i.e. en/digits/1.gsm, it/digits/1.gsm or default to digits/1.gsm).
 * The latter permits a language to be entirely in one directory.
 */
int ast_language_is_prefix = 1;

static AST_RWLIST_HEAD_STATIC(formats, ast_format);

int __ast_format_register(const struct ast_format *f, struct ast_module *mod)
{
   struct ast_format *tmp;

   AST_RWLIST_WRLOCK(&formats);
   AST_RWLIST_TRAVERSE(&formats, tmp, list) {
      if (!strcasecmp(f->name, tmp->name)) {
         AST_RWLIST_UNLOCK(&formats);
         ast_log(LOG_WARNING, "Tried to register '%s' format, already registered\n", f->name);
         return -1;
      }
   }
   if (!(tmp = ast_calloc(1, sizeof(*tmp)))) {
      AST_RWLIST_UNLOCK(&formats);
      return -1;
   }
   *tmp = *f;
   tmp->module = mod;
   if (tmp->buf_size) {
      /*
       * Align buf_size properly, rounding up to the machine-specific
       * alignment for pointers.
       */
      struct _test_align { void *a, *b; } p;
      int align = (char *)&p.b - (char *)&p.a;
      tmp->buf_size = ((f->buf_size + align - 1)/align)*align;
   }
   
   memset(&tmp->list, 0, sizeof(tmp->list));

   AST_RWLIST_INSERT_HEAD(&formats, tmp, list);
   AST_RWLIST_UNLOCK(&formats);
   if (option_verbose > 1)
      ast_verbose( VERBOSE_PREFIX_2 "Registered file format %s, extension(s) %s\n", f->name, f->exts);

   return 0;
}

int ast_format_unregister(const char *name)
{
   struct ast_format *tmp;
   int res = -1;

   AST_RWLIST_WRLOCK(&formats);
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&formats, tmp, list) {
      if (!strcasecmp(name, tmp->name)) {
         AST_RWLIST_REMOVE_CURRENT(&formats, list);
         free(tmp);
         res = 0;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END
   AST_RWLIST_UNLOCK(&formats);

   if (!res) {
      if (option_verbose > 1)
         ast_verbose( VERBOSE_PREFIX_2 "Unregistered format %s\n", name);
   } else
      ast_log(LOG_WARNING, "Tried to unregister format %s, already unregistered\n", name);

   return res;
}

int ast_stopstream(struct ast_channel *tmp)
{
   /* Stop a running stream if there is one */
   if (tmp->stream) {
      ast_closestream(tmp->stream);
      tmp->stream = NULL;
      if (tmp->oldwriteformat && ast_set_write_format(tmp, tmp->oldwriteformat))
         ast_log(LOG_WARNING, "Unable to restore format back to %d\n", tmp->oldwriteformat);
   }
   return 0;
}

int ast_writestream(struct ast_filestream *fs, struct ast_frame *f)
{
   int res = -1;
   int alt = 0;
   if (f->frametype == AST_FRAME_VIDEO) {
      if (fs->fmt->format < AST_FORMAT_MAX_AUDIO) {
         /* This is the audio portion.  Call the video one... */
         if (!fs->vfs && fs->filename) {
            const char *type = ast_getformatname(f->subclass & ~0x1);
            fs->vfs = ast_writefile(fs->filename, type, NULL, fs->flags, 0, fs->mode);
            ast_log(LOG_DEBUG, "Opened video output file\n");
         }
         if (fs->vfs)
            return ast_writestream(fs->vfs, f);
         /* else ignore */
         return 0;            
      } else {
         /* Might / might not have mark set */
         alt = 1;
      }
   } else if (f->frametype != AST_FRAME_VOICE) {
      ast_log(LOG_WARNING, "Tried to write non-voice frame\n");
      return -1;
   }
   if (((fs->fmt->format | alt) & f->subclass) == f->subclass) {
      res =  fs->fmt->write(fs, f);
      if (res < 0) 
         ast_log(LOG_WARNING, "Natural write failed\n");
      else if (res > 0)
         ast_log(LOG_WARNING, "Huh??\n");
   } else {
      /* XXX If they try to send us a type of frame that isn't the normal frame, and isn't
             the one we've setup a translator for, we do the "wrong thing" XXX */
      if (fs->trans && f->subclass != fs->lastwriteformat) {
         ast_translator_free_path(fs->trans);
         fs->trans = NULL;
      }
      if (!fs->trans) 
         fs->trans = ast_translator_build_path(fs->fmt->format, f->subclass);
      if (!fs->trans)
         ast_log(LOG_WARNING, "Unable to translate to format %s, source format %s\n",
            fs->fmt->name, ast_getformatname(f->subclass));
      else {
         struct ast_frame *trf;
         fs->lastwriteformat = f->subclass;
         /* Get the translated frame but don't consume the original in case they're using it on another stream */
         trf = ast_translate(fs->trans, f, 0);
         if (trf) {
            res = fs->fmt->write(fs, trf);
            if (res) 
               ast_log(LOG_WARNING, "Translated frame write failed\n");
         } else
            res = 0;
      }
   }
   return res;
}

static int copy(const char *infile, const char *outfile)
{
   int ifd, ofd, len;
   char buf[4096];   /* XXX make it lerger. */

   if ((ifd = open(infile, O_RDONLY)) < 0) {
      ast_log(LOG_WARNING, "Unable to open %s in read-only mode\n", infile);
      return -1;
   }
   if ((ofd = open(outfile, O_WRONLY | O_TRUNC | O_CREAT, 0600)) < 0) {
      ast_log(LOG_WARNING, "Unable to open %s in write-only mode\n", outfile);
      close(ifd);
      return -1;
   }
   while ( (len = read(ifd, buf, sizeof(buf)) ) ) {
      int res;
      if (len < 0) {
         ast_log(LOG_WARNING, "Read failed on %s: %s\n", infile, strerror(errno));
         break;
      }
      /* XXX handle partial writes */
      res = write(ofd, buf, len);
      if (res != len) {
         ast_log(LOG_WARNING, "Write failed on %s (%d of %d): %s\n", outfile, res, len, strerror(errno));
         len = -1; /* error marker */
         break;
      }
   }
   close(ifd);
   close(ofd);
   if (len < 0) {
      unlink(outfile);
      return -1; /* error */
   }
   return 0;   /* success */
}

/*!
 * \brief construct a filename. Absolute pathnames are preserved,
 * relative names are prefixed by the sounds/ directory.
 * The wav49 suffix is replaced by 'WAV'.
 * Returns a malloc'ed string to be freed by the caller.
 */
static char *build_filename(const char *filename, const char *ext)
{
   char *fn = NULL;

   if (!strcmp(ext, "wav49"))
      ext = "WAV";

   if (filename[0] == '/')
      asprintf(&fn, "%s.%s", filename, ext);
   else
      asprintf(&fn, "%s/sounds/%s.%s",
         ast_config_AST_DATA_DIR, filename, ext);
   return fn;
}

/* compare type against the list 'exts' */
/* XXX need a better algorithm */
static int exts_compare(const char *exts, const char *type)
{
   char tmp[256];
   char *stringp = tmp, *ext;

   ast_copy_string(tmp, exts, sizeof(tmp));
   while ((ext = strsep(&stringp, "|"))) {
      if (!strcmp(ext, type))
         return 1;
   }

   return 0;
}

static struct ast_filestream *get_filestream(struct ast_format *fmt, FILE *bfile)
{
   struct ast_filestream *s;

   int l = sizeof(*s) + fmt->buf_size + fmt->desc_size;  /* total allocation size */
   if ( (s = ast_calloc(1, l)) == NULL)
      return NULL;
   s->fmt = fmt;
   s->f = bfile;

   if (fmt->desc_size)
      s->private = ((char *)(s+1)) + fmt->buf_size;
   if (fmt->buf_size)
      s->buf = (char *)(s+1);
   s->fr.src = fmt->name;
   return s;
}

/*
 * Default implementations of open and rewrite.
 * Only use them if you don't have expensive stuff to do.
 */
enum wrap_fn { WRAP_OPEN, WRAP_REWRITE };

static int fn_wrapper(struct ast_filestream *s, const char *comment, enum wrap_fn mode)
{
   struct ast_format *f = s->fmt;
   int ret = -1;

   if (mode == WRAP_OPEN && f->open && f->open(s))
                ast_log(LOG_WARNING, "Unable to open format %s\n", f->name);
   else if (mode == WRAP_REWRITE && f->rewrite && f->rewrite(s, comment))
                ast_log(LOG_WARNING, "Unable to rewrite format %s\n", f->name);
   else {
      /* preliminary checks succeed. update usecount */
      ast_module_ref(f->module);
      ret = 0;
   }
        return ret;
}

static int rewrite_wrapper(struct ast_filestream *s, const char *comment)
{
   return fn_wrapper(s, comment, WRAP_REWRITE);
}
                
static int open_wrapper(struct ast_filestream *s)
{
   return fn_wrapper(s, NULL, WRAP_OPEN);
}

enum file_action {
   ACTION_EXISTS = 1, /* return matching format if file exists, 0 otherwise */
   ACTION_DELETE, /* delete file, return 0 on success, -1 on error */
   ACTION_RENAME, /* rename file. return 0 on success, -1 on error */
   ACTION_OPEN,
   ACTION_COPY /* copy file. return 0 on success, -1 on error */
};

/*!
 * \brief perform various actions on a file. Second argument
 * arg2 depends on the command:
 * unused for EXISTS and DELETE
 * destination file name (const char *) for COPY and RENAME
 *    struct ast_channel * for OPEN
 * if fmt is NULL, OPEN will return the first matching entry,
 * whereas other functions will run on all matching entries.
 */
static int ast_filehelper(const char *filename, const void *arg2, const char *fmt, const enum file_action action)
{
   struct ast_format *f;
   int res = (action == ACTION_EXISTS) ? 0 : -1;

   AST_RWLIST_RDLOCK(&formats);
   /* Check for a specific format */
   AST_RWLIST_TRAVERSE(&formats, f, list) {
      char *stringp, *ext = NULL;

      if (fmt && !exts_compare(f->exts, fmt))
         continue;

      /* Look for a file matching the supported extensions.
       * The file must exist, and for OPEN, must match
       * one of the formats supported by the channel.
       */
      stringp = ast_strdupa(f->exts);  /* this is in the stack so does not need to be freed */
      while ( (ext = strsep(&stringp, "|")) ) {
         struct stat st;
         char *fn = build_filename(filename, ext);

         if (fn == NULL)
            continue;

         if ( stat(fn, &st) ) { /* file not existent */
            free(fn);
            continue;
         }
         /* for 'OPEN' we need to be sure that the format matches
          * what the channel can process
          */
         if (action == ACTION_OPEN) {
            struct ast_channel *chan = (struct ast_channel *)arg2;
            FILE *bfile;
            struct ast_filestream *s;

            if ( !(chan->writeformat & f->format) &&
                 !(f->format >= AST_FORMAT_MAX_AUDIO && fmt)) {
               free(fn);
               continue;   /* not a supported format */
            }
            if ( (bfile = fopen(fn, "r")) == NULL) {
               free(fn);
               continue;   /* cannot open file */
            }
            s = get_filestream(f, bfile);
            if (!s) {
               fclose(bfile);
               free(fn);   /* cannot allocate descriptor */
               continue;
            }
            if (open_wrapper(s)) {
               fclose(bfile);
               free(fn);
               free(s);
               continue;   /* cannot run open on file */
            }
            /* ok this is good for OPEN */
            res = 1; /* found */
            s->lasttimeout = -1;
            s->fmt = f;
            s->trans = NULL;
            s->filename = NULL;
            if (s->fmt->format < AST_FORMAT_MAX_AUDIO) {
               if (chan->stream)
                  ast_closestream(chan->stream);
               chan->stream = s;
            } else {
               if (chan->vstream)
                  ast_closestream(chan->vstream);
               chan->vstream = s;
            }
            free(fn);
            break;
         }
         switch (action) {
         case ACTION_OPEN:
            break;   /* will never get here */

         case ACTION_EXISTS:  /* return the matching format */
            res |= f->format;
            break;

         case ACTION_DELETE:
            if ( (res = unlink(fn)) )
               ast_log(LOG_WARNING, "unlink(%s) failed: %s\n", fn, strerror(errno));
            break;

         case ACTION_RENAME:
         case ACTION_COPY: {
            char *nfn = build_filename((const char *)arg2, ext);
            if (!nfn)
               ast_log(LOG_WARNING, "Out of memory\n");
            else {
               res = action == ACTION_COPY ? copy(fn, nfn) : rename(fn, nfn);
               if (res)
                  ast_log(LOG_WARNING, "%s(%s,%s) failed: %s\n",
                     action == ACTION_COPY ? "copy" : "rename",
                      fn, nfn, strerror(errno));
               free(nfn);
            }
             }
            break;

         default:
            ast_log(LOG_WARNING, "Unknown helper %d\n", action);
         }
         free(fn);
      }
   }
   AST_RWLIST_UNLOCK(&formats);
   return res;
}

/*!
 * \brief helper routine to locate a file with a given format
 * and language preference.
 * Try preflang, preflang with stripped '_' suffix, or NULL.
 * In the standard asterisk, language goes just before the last component.
 * In an alternative configuration, the language should be a prefix
 * to the actual filename.
 *
 * The last parameter(s) point to a buffer of sufficient size,
 * which on success is filled with the matching filename.
 */
static int fileexists_core(const char *filename, const char *fmt, const char *preflang,
      char *buf, int buflen)
{
   int res = -1;
   int langlen;   /* length of language string */
   const char *c = strrchr(filename, '/');
   int offset = c ? c - filename + 1 : 0; /* points right after the last '/' */

   if (preflang == NULL)
      preflang = "";
   langlen = strlen(preflang);
   
   if (buflen < langlen + strlen(filename) + 2) {
      ast_log(LOG_WARNING, "buffer too small\n");
      buf[0] = '\0'; /* set to empty */
      buf = alloca(langlen + strlen(filename) + 2);   /* room for everything */
   }
   if (buf == NULL)
      return 0;
   buf[0] = '\0';
   for (;;) {
      if (ast_language_is_prefix) { /* new layout */
         if (langlen) {
            strcpy(buf, preflang);
            buf[langlen] = '/';
            strcpy(buf + langlen + 1, filename);
         } else
            strcpy(buf, filename);  /* first copy the full string */
      } else { /* old layout */
         strcpy(buf, filename);  /* first copy the full string */
         if (langlen) {
            /* insert the language and suffix if needed */
            strcpy(buf + offset, preflang);
            sprintf(buf + offset + langlen, "/%s", filename + offset);
         }
      }
      res = ast_filehelper(buf, NULL, fmt, ACTION_EXISTS);
      if (res > 0)      /* found format */
         break;
      if (langlen == 0) /* no more formats */
         break;
      if (preflang[langlen] == '_') /* we are on the local suffix */
         langlen = 0;   /* try again with no language */
      else
         langlen = (c = strchr(preflang, '_')) ? c - preflang : 0;
   }
   return res;
}

struct ast_filestream *ast_openstream(struct ast_channel *chan, const char *filename, const char *preflang)
{
   return ast_openstream_full(chan, filename, preflang, 0);
}

struct ast_filestream *ast_openstream_full(struct ast_channel *chan, const char *filename, const char *preflang, int asis)
{
   /* 
    * Use fileexists_core() to find a file in a compatible
    * language and format, set up a suitable translator,
    * and open the stream.
    */
   int fmts, res, buflen;
   char *buf;

   if (!asis) {
      /* do this first, otherwise we detect the wrong writeformat */
      ast_stopstream(chan);
      if (chan->generator)
         ast_deactivate_generator(chan);
   }
   if (preflang == NULL)
      preflang = "";
   buflen = strlen(preflang) + strlen(filename) + 2;
   buf = alloca(buflen);
   if (buf == NULL)
      return NULL;
   fmts = fileexists_core(filename, NULL, preflang, buf, buflen);
   if (fmts > 0)
      fmts &= AST_FORMAT_AUDIO_MASK;
   if (fmts < 1) {
      ast_log(LOG_WARNING, "File %s does not exist in any format\n", filename);
      return NULL;
   }
   chan->oldwriteformat = chan->writeformat;
   /* Set the channel to a format we can work with */
   res = ast_set_write_format(chan, fmts);
   res = ast_filehelper(buf, chan, NULL, ACTION_OPEN);
   if (res >= 0)
      return chan->stream;
   return NULL;
}

struct ast_filestream *ast_openvstream(struct ast_channel *chan, const char *filename, const char *preflang)
{
   /* As above, but for video. But here we don't have translators
    * so we must enforce a format.
    */
   unsigned int format;
   char *buf;
   int buflen;

   if (preflang == NULL)
      preflang = "";
   buflen = strlen(preflang) + strlen(filename) + 2;
   buf = alloca(buflen);
   if (buf == NULL)
      return NULL;

   for (format = AST_FORMAT_MAX_AUDIO << 1; format <= AST_FORMAT_MAX_VIDEO; format = format << 1) {
      int fd;
      const char *fmt;

      if (!(chan->nativeformats & format))
         continue;
      fmt = ast_getformatname(format);
      if ( fileexists_core(filename, fmt, preflang, buf, buflen) < 1)   /* no valid format */
         continue;
      fd = ast_filehelper(buf, chan, fmt, ACTION_OPEN);
      if (fd >= 0)
         return chan->vstream;
      ast_log(LOG_WARNING, "File %s has video but couldn't be opened\n", filename);
   }
   return NULL;
}

struct ast_frame *ast_readframe(struct ast_filestream *s)
{
   struct ast_frame *f = NULL;
   int whennext = 0; 
   if (s && s->fmt)
      f = s->fmt->read(s, &whennext);
   return f;
}

static int ast_readaudio_callback(void *data)
{
   struct ast_filestream *s = data;
   int whennext = 0;

   while(!whennext) {
      struct ast_frame *fr = s->fmt->read(s, &whennext);
      if (!fr /* stream complete */ || ast_write(s->owner, fr) /* error writing */) {
         if (fr)
            ast_log(LOG_WARNING, "Failed to write frame\n");
         s->owner->streamid = -1;
#ifdef HAVE_ZAPTEL
         ast_settimeout(s->owner, 0, NULL, NULL);
#endif         
         return 0;
      }
   }
   if (whennext != s->lasttimeout) {
#ifdef HAVE_ZAPTEL
      if (s->owner->timingfd > -1)
         ast_settimeout(s->owner, whennext, ast_readaudio_callback, s);
      else
#endif      
         s->owner->streamid = ast_sched_add(s->owner->sched, whennext/8, ast_readaudio_callback, s);
      s->lasttimeout = whennext;
      return 0;
   }
   return 1;
}

static int ast_readvideo_callback(void *data)
{
   struct ast_filestream *s = data;
   int whennext = 0;

   while (!whennext) {
      struct ast_frame *fr = s->fmt->read(s, &whennext);
      if (!fr || ast_write(s->owner, fr)) { /* no stream or error, as above */
         if (fr)
            ast_log(LOG_WARNING, "Failed to write frame\n");
         s->owner->vstreamid = -1;
         return 0;
      }
   }
   if (whennext != s->lasttimeout) {
      s->owner->vstreamid = ast_sched_add(s->owner->sched, whennext/8, ast_readvideo_callback, s);
      s->lasttimeout = whennext;
      return 0;
   }
   return 1;
}

int ast_applystream(struct ast_channel *chan, struct ast_filestream *s)
{
   s->owner = chan;
   return 0;
}

int ast_playstream(struct ast_filestream *s)
{
   if (s->fmt->format < AST_FORMAT_MAX_AUDIO)
      ast_readaudio_callback(s);
   else
      ast_readvideo_callback(s);
   return 0;
}

int ast_seekstream(struct ast_filestream *fs, off_t sample_offset, int whence)
{
   return fs->fmt->seek(fs, sample_offset, whence);
}

int ast_truncstream(struct ast_filestream *fs)
{
   return fs->fmt->trunc(fs);
}

off_t ast_tellstream(struct ast_filestream *fs)
{
   return fs->fmt->tell(fs);
}

int ast_stream_fastforward(struct ast_filestream *fs, off_t ms)
{
   return ast_seekstream(fs, ms * DEFAULT_SAMPLES_PER_MS, SEEK_CUR);
}

int ast_stream_rewind(struct ast_filestream *fs, off_t ms)
{
   return ast_seekstream(fs, -ms * DEFAULT_SAMPLES_PER_MS, SEEK_CUR);
}

int ast_closestream(struct ast_filestream *f)
{
   char *cmd = NULL;
   size_t size = 0;
   /* Stop a running stream if there is one */
   if (f->owner) {
      if (f->fmt->format < AST_FORMAT_MAX_AUDIO) {
         f->owner->stream = NULL;
         if (f->owner->streamid > -1)
            ast_sched_del(f->owner->sched, f->owner->streamid);
         f->owner->streamid = -1;
#ifdef HAVE_ZAPTEL
         ast_settimeout(f->owner, 0, NULL, NULL);
#endif         
      } else {
         f->owner->vstream = NULL;
         if (f->owner->vstreamid > -1)
            ast_sched_del(f->owner->sched, f->owner->vstreamid);
         f->owner->vstreamid = -1;
      }
   }
   /* destroy the translator on exit */
   if (f->trans)
      ast_translator_free_path(f->trans);

   if (f->realfilename && f->filename) {
         size = strlen(f->filename) + strlen(f->realfilename) + 15;
         cmd = alloca(size);
         memset(cmd,0,size);
         snprintf(cmd,size,"/bin/mv -f %s %s",f->filename,f->realfilename);
         ast_safe_system(cmd);
   }

   if (f->filename)
      free(f->filename);
   if (f->realfilename)
      free(f->realfilename);
   if (f->fmt->close)
      f->fmt->close(f);
   fclose(f->f);
   if (f->vfs)
      ast_closestream(f->vfs);
   ast_module_unref(f->fmt->module);
   free(f);
   return 0;
}


/*
 * Look the various language-specific places where a file could exist.
 */
int ast_fileexists(const char *filename, const char *fmt, const char *preflang)
{
   char *buf;
   int buflen;

   if (preflang == NULL)
      preflang = "";
   buflen = strlen(preflang) + strlen(filename) + 2;  /* room for everything */
   buf = alloca(buflen);
   if (buf == NULL)
      return 0;
   return fileexists_core(filename, fmt, preflang, buf, buflen);
}

int ast_filedelete(const char *filename, const char *fmt)
{
   return ast_filehelper(filename, NULL, fmt, ACTION_DELETE);
}

int ast_filerename(const char *filename, const char *filename2, const char *fmt)
{
   return ast_filehelper(filename, filename2, fmt, ACTION_RENAME);
}

int ast_filecopy(const char *filename, const char *filename2, const char *fmt)
{
   return ast_filehelper(filename, filename2, fmt, ACTION_COPY);
}

int ast_streamfile(struct ast_channel *chan, const char *filename, const char *preflang)
{
   struct ast_filestream *fs;
   struct ast_filestream *vfs=NULL;
   char fmt[256];

   fs = ast_openstream(chan, filename, preflang);
   if (fs)
      vfs = ast_openvstream(chan, filename, preflang);
   if (vfs)
      ast_log(LOG_DEBUG, "Ooh, found a video stream, too, format %s\n", ast_getformatname(vfs->fmt->format));
   if (fs){
      if (ast_applystream(chan, fs))
         return -1;
      if (vfs && ast_applystream(chan, vfs))
         return -1;
      if (ast_playstream(fs))
         return -1;
      if (vfs && ast_playstream(vfs))
         return -1;
      if (option_verbose > 2)
         ast_verbose(VERBOSE_PREFIX_3 "<%s> Playing '%s' (language '%s')\n", chan->name, filename, preflang ? preflang : "default");

      return 0;
   }
   ast_log(LOG_WARNING, "Unable to open %s (format %s): %s\n", filename, ast_getformatname_multiple(fmt, sizeof(fmt), chan->nativeformats), strerror(errno));
   return -1;
}

struct ast_filestream *ast_readfile(const char *filename, const char *type, const char *comment, int flags, int check, mode_t mode)
{
   FILE *bfile;
   struct ast_format *f;
   struct ast_filestream *fs = NULL;
   char *fn;

   AST_RWLIST_RDLOCK(&formats);

   AST_RWLIST_TRAVERSE(&formats, f, list) {
      fs = NULL;
      if (!exts_compare(f->exts, type))
         continue;

      fn = build_filename(filename, type);
      errno = 0;
      bfile = fopen(fn, "r");
      if (!bfile || (fs = get_filestream(f, bfile)) == NULL ||
          open_wrapper(fs) ) {
         ast_log(LOG_WARNING, "Unable to open %s\n", fn);
         if (fs)
            ast_free(fs);
         if (bfile)
            fclose(bfile);
         free(fn);
         continue;
      }
      /* found it */
      fs->trans = NULL;
      fs->fmt = f;
      fs->flags = flags;
      fs->mode = mode;
      fs->filename = strdup(filename);
      fs->vfs = NULL;
      break;
   }

   AST_RWLIST_UNLOCK(&formats);
   if (!fs) 
      ast_log(LOG_WARNING, "No such format '%s'\n", type);

   return fs;
}

struct ast_filestream *ast_writefile(const char *filename, const char *type, const char *comment, int flags, int check, mode_t mode)
{
   int fd, myflags = 0;
   /* compiler claims this variable can be used before initialization... */
   FILE *bfile = NULL;
   struct ast_format *f;
   struct ast_filestream *fs = NULL;
   char *buf = NULL;
   size_t size = 0;
   int format_found = 0;

   AST_RWLIST_RDLOCK(&formats);

   /* set the O_TRUNC flag if and only if there is no O_APPEND specified */
   /* We really can't use O_APPEND as it will break WAV header updates */
   if (flags & O_APPEND) { 
      flags &= ~O_APPEND;
   } else {
      myflags = O_TRUNC;
   }
   
   myflags |= O_WRONLY | O_CREAT;

   /* XXX need to fix this - we should just do the fopen,
    * not open followed by fdopen()
    */
   AST_RWLIST_TRAVERSE(&formats, f, list) {
      char *fn, *orig_fn = NULL;
      if (fs)
         break;

      if (!exts_compare(f->exts, type))
         continue;
      else
         format_found = 1;

      fn = build_filename(filename, type);
      fd = open(fn, flags | myflags, mode);
      if (fd > -1) {
         /* fdopen() the resulting file stream */
         bfile = fdopen(fd, ((flags | myflags) & O_RDWR) ? "w+" : "w");
         if (!bfile) {
            ast_log(LOG_WARNING, "Whoa, fdopen failed: %s!\n", strerror(errno));
            close(fd);
            fd = -1;
         }
      }
      
      if (ast_opt_cache_record_files && (fd > -1)) {
         char *c;

         fclose(bfile); /* this also closes fd */
         /*
           We touch orig_fn just as a place-holder so other things (like vmail) see the file is there.
           What we are really doing is writing to record_cache_dir until we are done then we will mv the file into place.
         */
         orig_fn = ast_strdupa(fn);
         for (c = fn; *c; c++)
            if (*c == '/')
               *c = '_';

         size = strlen(fn) + strlen(record_cache_dir) + 2;
         buf = alloca(size);
         strcpy(buf, record_cache_dir);
         strcat(buf, "/");
         strcat(buf, fn);
         free(fn);
         fn = buf;
         fd = open(fn, flags | myflags, mode);
         if (fd > -1) {
            /* fdopen() the resulting file stream */
            bfile = fdopen(fd, ((flags | myflags) & O_RDWR) ? "w+" : "w");
            if (!bfile) {
               ast_log(LOG_WARNING, "Whoa, fdopen failed: %s!\n", strerror(errno));
               close(fd);
               fd = -1;
            }
         }
      }
      if (fd > -1) {
         errno = 0;
         fs = get_filestream(f, bfile);
         if (!fs || rewrite_wrapper(fs, comment)) {
            ast_log(LOG_WARNING, "Unable to rewrite %s\n", fn);
            close(fd);
            if (orig_fn) {
               unlink(fn);
               unlink(orig_fn);
            }
            if (fs)
               ast_free(fs);
         }
         fs->trans = NULL;
         fs->fmt = f;
         fs->flags = flags;
         fs->mode = mode;
         if (orig_fn) {
            fs->realfilename = strdup(orig_fn);
            fs->filename = strdup(fn);
         } else {
            fs->realfilename = NULL;
            fs->filename = strdup(filename);
         }
         fs->vfs = NULL;
         /* If truncated, we'll be at the beginning; if not truncated, then append */
         f->seek(fs, 0, SEEK_END);
      } else if (errno != EEXIST) {
         ast_log(LOG_WARNING, "Unable to open file %s: %s\n", fn, strerror(errno));
         if (orig_fn)
            unlink(orig_fn);
      }
      /* if buf != NULL then fn is already free and pointing to it */
      if (!buf)
         free(fn);
   }

   AST_RWLIST_UNLOCK(&formats);

   if (!format_found)
      ast_log(LOG_WARNING, "No such format '%s'\n", type);

   return fs;
}

/*!
 * \brief the core of all waitstream() functions
 */
static int waitstream_core(struct ast_channel *c, const char *breakon,
   const char *forward, const char *rewind, int skip_ms,
   int audiofd, int cmdfd,  const char *context)
{
   if (!breakon)
      breakon = "";
   if (!forward)
      forward = "";
   if (!rewind)
      rewind = "";
   
   while (c->stream) {
      int res;
      int ms = ast_sched_wait(c->sched);
      if (ms < 0 && !c->timingfunc) {
         ast_stopstream(c);
         break;
      }
      if (ms < 0)
         ms = 1000;
      if (cmdfd < 0) {
         res = ast_waitfor(c, ms);
         if (res < 0) {
            ast_log(LOG_WARNING, "Select failed (%s)\n", strerror(errno));
            return res;
         }
      } else {
         int outfd;
         struct ast_channel *rchan = ast_waitfor_nandfds(&c, 1, &cmdfd, (cmdfd > -1) ? 1 : 0, NULL, &outfd, &ms);
         if (!rchan && (outfd < 0) && (ms)) {
            /* Continue */
            if (errno == EINTR)
               continue;
            ast_log(LOG_WARNING, "Wait failed (%s)\n", strerror(errno));
            return -1;
         } else if (outfd > -1) { /* this requires cmdfd set */
            /* The FD we were watching has something waiting */
            return 1;
         }
         /* if rchan is set, it is 'c' */
         res = rchan ? 1 : 0; /* map into 'res' values */
      }
      if (res > 0) {
         struct ast_frame *fr = ast_read(c);
         if (!fr)
            return -1;
         switch(fr->frametype) {
         case AST_FRAME_DTMF_END:
            if (context) {
               const char exten[2] = { fr->subclass, '\0' };
               if (ast_exists_extension(c, context, exten, 1, c->cid.cid_num)) {
                  res = fr->subclass;
                  ast_frfree(fr);
                  return res;
               }
            } else {
               res = fr->subclass;
               if (strchr(forward,res)) {
                  ast_stream_fastforward(c->stream, skip_ms);
               } else if (strchr(rewind,res)) {
                  ast_stream_rewind(c->stream, skip_ms);
               } else if (strchr(breakon, res)) {
                  ast_frfree(fr);
                  return res;
               }              
            }
            break;
         case AST_FRAME_CONTROL:
            switch(fr->subclass) {
            case AST_CONTROL_HANGUP:
            case AST_CONTROL_BUSY:
            case AST_CONTROL_CONGESTION:
               ast_frfree(fr);
               return -1;
            case AST_CONTROL_RINGING:
            case AST_CONTROL_ANSWER:
            case AST_CONTROL_VIDUPDATE:
            case AST_CONTROL_HOLD:
            case AST_CONTROL_UNHOLD:
               /* Unimportant */
               break;
            default:
               ast_log(LOG_WARNING, "Unexpected control subclass '%d'\n", fr->subclass);
            }
            break;
         case AST_FRAME_VOICE:
            /* Write audio if appropriate */
            if (audiofd > -1)
               write(audiofd, fr->data, fr->datalen);
         default:
            /* Ignore all others */
            break;
         }
         ast_frfree(fr);
      }
      ast_sched_runq(c->sched);
   }
   return (c->_softhangup ? -1 : 0);
}

int ast_waitstream_fr(struct ast_channel *c, const char *breakon, const char *forward, const char *rewind, int ms)
{
   return waitstream_core(c, breakon, forward, rewind, ms,
      -1 /* no audiofd */, -1 /* no cmdfd */, NULL /* no context */);
}

int ast_waitstream(struct ast_channel *c, const char *breakon)
{
   return waitstream_core(c, breakon, NULL, NULL, 0, -1, -1, NULL);
}

int ast_waitstream_full(struct ast_channel *c, const char *breakon, int audiofd, int cmdfd)
{
   return waitstream_core(c, breakon, NULL, NULL, 0,
      audiofd, cmdfd, NULL /* no context */);
}

int ast_waitstream_exten(struct ast_channel *c, const char *context)
{
   /* Waitstream, with return in the case of a valid 1 digit extension */
   /* in the current or specified context being pressed */

   if (!context)
      context = c->context;
   return waitstream_core(c, NULL, NULL, NULL, 0,
      -1, -1, context);
}

/*
 * if the file name is non-empty, try to play it.
 * Return 0 if success, -1 if error, digit if interrupted by a digit.
 * If digits == "" then we can simply check for non-zero.
 */
int ast_stream_and_wait(struct ast_channel *chan, const char *file,
   const char *language, const char *digits)
{
        int res = 0;
        if (!ast_strlen_zero(file)) {
                res =  ast_streamfile(chan, file, language);
                if (!res)
                        res = ast_waitstream(chan, digits);
        }
        return res;
} 

static int show_file_formats(int fd, int argc, char *argv[])
{
#define FORMAT "%-10s %-10s %-20s\n"
#define FORMAT2 "%-10s %-10s %-20s\n"
   struct ast_format *f;
   int count_fmt = 0;

   if (argc != 4)
      return RESULT_SHOWUSAGE;
   ast_cli(fd, FORMAT, "Format", "Name", "Extensions");

   AST_RWLIST_RDLOCK(&formats);
   AST_RWLIST_TRAVERSE(&formats, f, list) {
      ast_cli(fd, FORMAT2, ast_getformatname(f->format), f->name, f->exts);
      count_fmt++;
   }
   AST_RWLIST_UNLOCK(&formats);
   ast_cli(fd, "%d file formats registered.\n", count_fmt);
   return RESULT_SUCCESS;
#undef FORMAT
#undef FORMAT2
}

static int show_file_formats_deprecated(int fd, int argc, char *argv[])
{
#define FORMAT "%-10s %-10s %-20s\n"
#define FORMAT2 "%-10s %-10s %-20s\n"
   struct ast_format *f;
   int count_fmt = 0;
   
   if (argc != 3)
      return RESULT_SHOWUSAGE;
   ast_cli(fd, FORMAT, "Format", "Name", "Extensions");
   
   if (AST_LIST_LOCK(&formats)) {
      ast_log(LOG_WARNING, "Unable to lock format list\n");
      return -1;
   }
   
   AST_LIST_TRAVERSE(&formats, f, list) {
      ast_cli(fd, FORMAT2, ast_getformatname(f->format), f->name, f->exts);
      count_fmt++;
   }
   AST_LIST_UNLOCK(&formats);
   ast_cli(fd, "%d file formats registered.\n", count_fmt);
   return RESULT_SUCCESS;
#undef FORMAT
#undef FORMAT2
}

char show_file_formats_usage[] = 
"Usage: core show file formats\n"
"       Displays currently registered file formats (if any)\n";

struct ast_cli_entry cli_show_file_formats_deprecated = {
   { "show", "file", "formats" },
   show_file_formats_deprecated, NULL,
   NULL };

struct ast_cli_entry cli_file[] = {
   { { "core", "show", "file", "formats" },
   show_file_formats, "Displays file formats",
   show_file_formats_usage, NULL, &cli_show_file_formats_deprecated },
};

int ast_file_init(void)
{
   ast_cli_register_multiple(cli_file, sizeof(cli_file) / sizeof(struct ast_cli_entry));
   return 0;
}

---