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>
 */

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

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 406567 $")

#include <dirent.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <math.h>

#include "asterisk/_private.h"   /* declare ast_file_init() */
#include "asterisk/paths.h"   /* use ast_config_AST_DATA_DIR */
#include "asterisk/mod_format.h"
#include "asterisk/cli.h"
#include "asterisk/channel.h"
#include "asterisk/sched.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"
#include "asterisk/astobj2.h"
#include "asterisk/test.h"

/*! \brief
 * 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.
 *
 * This is settable in asterisk.conf.
 */
int ast_language_is_prefix = 1;

static AST_RWLIST_HEAD_STATIC(formats, ast_format_def);

int __ast_format_def_register(const struct ast_format_def *f, struct ast_module *mod)
{
   struct ast_format_def *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);
   ast_verb(2, "Registered file format %s, extension(s) %s\n", f->name, f->exts);

   return 0;
}

int ast_format_def_unregister(const char *name)
{
   struct ast_format_def *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(list);
         ast_free(tmp);
         res = 0;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;
   AST_RWLIST_UNLOCK(&formats);

   if (!res)
      ast_verb(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)
{
   ast_channel_lock(tmp);

   /* Stop a running stream if there is one */
   if (ast_channel_stream(tmp)) {
      ast_closestream(ast_channel_stream(tmp));
      ast_channel_stream_set(tmp, NULL);
      if (ast_channel_oldwriteformat(tmp)->id && ast_set_write_format(tmp, ast_channel_oldwriteformat(tmp)))
         ast_log(LOG_WARNING, "Unable to restore format back to %s\n", ast_getformatname(ast_channel_oldwriteformat(tmp)));
   }
   /* Stop the video stream too */
   if (ast_channel_vstream(tmp) != NULL) {
      ast_closestream(ast_channel_vstream(tmp));
      ast_channel_vstream_set(tmp, NULL);
   }

   ast_channel_unlock(tmp);

   return 0;
}

int ast_writestream(struct ast_filestream *fs, struct ast_frame *f)
{
   int res = -1;
   if (f->frametype == AST_FRAME_VIDEO) {
      if (AST_FORMAT_GET_TYPE(fs->fmt->format.id) == AST_FORMAT_TYPE_AUDIO) {
         /* This is the audio portion.  Call the video one... */
         if (!fs->vfs && fs->filename) {
            const char *type = ast_getformatname(&f->subclass.format);
            fs->vfs = ast_writefile(fs->filename, type, NULL, fs->flags, 0, fs->mode);
            ast_debug(1, "Opened video output file\n");
         }
         if (fs->vfs)
            return ast_writestream(fs->vfs, f);
         /* else ignore */
         return 0;
      }
   } else if (f->frametype != AST_FRAME_VOICE) {
      ast_log(LOG_WARNING, "Tried to write non-voice frame\n");
      return -1;
   }
   if (ast_format_cmp(&f->subclass.format, &fs->fmt->format) != AST_FORMAT_CMP_NOT_EQUAL) {
      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 && (ast_format_cmp(&f->subclass.format, &fs->lastwriteformat) != AST_FORMAT_CMP_EQUAL)) {
         ast_translator_free_path(fs->trans);
         fs->trans = NULL;
      }
      if (!fs->trans)
         fs->trans = ast_translator_build_path(&fs->fmt->format, &f->subclass.format);
      if (!fs->trans)
         ast_log(LOG_WARNING, "Unable to translate to format %s, source format %s\n",
            fs->fmt->name, ast_getformatname(&f->subclass.format));
      else {
         struct ast_frame *trf;
         ast_format_copy(&fs->lastwriteformat, &f->subclass.format);
         /* Get the translated frame but don't consume the original in case they're using it on another stream */
         if ((trf = ast_translate(fs->trans, f, 0))) {
            struct ast_frame *cur;

            /* the translator may have returned multiple frames, so process them */
            for (cur = trf; cur; cur = AST_LIST_NEXT(cur, frame_list)) {
               if ((res = fs->fmt->write(fs, trf))) {
                  ast_log(LOG_WARNING, "Translated frame write failed\n");
                  break;
               }
            }
            ast_frfree(trf);
         } 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, AST_FILE_MODE)) < 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] == '/') {
      if (ast_asprintf(&fn, "%s.%s", filename, ext) < 0) {
         fn = NULL;
      }
   } else {
      if (ast_asprintf(&fn, "%s/sounds/%s.%s",
              ast_config_AST_DATA_DIR, filename, ext) < 0) {
         fn = NULL;
      }
   }
   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;
}

/*! \internal \brief Close the file stream by canceling any pending read / write callbacks */
static void filestream_close(struct ast_filestream *f)
{
   enum ast_format_type format_type = AST_FORMAT_GET_TYPE(f->fmt->format.id);

   if (!f->owner) {
      return;
   }

   /* Stop a running stream if there is one */
   switch (format_type)
   {
   case AST_FORMAT_TYPE_AUDIO:
      ast_channel_stream_set(f->owner, NULL);
      AST_SCHED_DEL_ACCESSOR(ast_channel_sched(f->owner), f->owner, ast_channel_streamid, ast_channel_streamid_set);
      ast_settimeout(f->owner, 0, NULL, NULL);
      break;
   case AST_FORMAT_TYPE_VIDEO:
      ast_channel_vstream_set(f->owner, NULL);
      AST_SCHED_DEL_ACCESSOR(ast_channel_sched(f->owner), f->owner, ast_channel_vstreamid, ast_channel_vstreamid_set);
      break;
   default:
      ast_log(AST_LOG_WARNING, "Unable to schedule deletion of filestream with unsupported type %s\n", f->fmt->name);
      break;
   }
}

static void filestream_destructor(void *arg)
{
   struct ast_filestream *f = arg;
   int status;
   int pid = -1;

   /* Stop a running stream if there is one */
   filestream_close(f);

   /* destroy the translator on exit */
   if (f->trans)
      ast_translator_free_path(f->trans);

   if (f->fmt->close) {
      void (*closefn)(struct ast_filestream *) = f->fmt->close;
      closefn(f);
   }

   if (f->f) {
      fclose(f->f);
   }

   if (f->realfilename && f->filename) {
      pid = ast_safe_fork(0);
      if (!pid) {
         execl("/bin/mv", "mv", "-f", f->filename, f->realfilename, SENTINEL);
         _exit(1);
      }
      else if (pid > 0) {
         /* Block the parent until the move is complete.*/
         waitpid(pid, &status, 0);
      }
   }

   if (f->filename)
      free(f->filename);
   if (f->realfilename)
      free(f->realfilename);
   if (f->vfs)
      ast_closestream(f->vfs);
   if (f->write_buffer) {
      ast_free(f->write_buffer);
   }
   if (f->orig_chan_name)
      free((void *) f->orig_chan_name);
   ast_module_unref(f->fmt->module);
}

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

   int l = sizeof(*s) + fmt->buf_size + fmt->desc_size;  /* total allocation size */
   if ( (s = ao2_alloc(l, filestream_destructor)) == 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_def *f = s->fmt;
   int ret = -1;
   int (*openfn)(struct ast_filestream *s);

   if (mode == WRAP_OPEN && (openfn = f->open) && openfn(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 */
};

/*!
 * \internal
 * \brief perform various actions on a file. Second argument
 * \note arg2 depends on the command:
 * unused for DELETE
 *  optional ast_format_cap holding all the formats found for a file, for EXISTS.
 * 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 filehelper(const char *filename, const void *arg2, const char *fmt, const enum file_action action)
{
   struct ast_format_def *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 */
            ast_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 ((ast_format_cmp(ast_channel_writeformat(chan), &f->format) == AST_FORMAT_CMP_NOT_EQUAL) &&
                 !(((AST_FORMAT_GET_TYPE(f->format.id) == AST_FORMAT_TYPE_AUDIO) && fmt) ||
                 ((AST_FORMAT_GET_TYPE(f->format.id) == AST_FORMAT_TYPE_VIDEO) && fmt))) {
               ast_free(fn);
               continue;   /* not a supported format */
            }
            if ( (bfile = fopen(fn, "r")) == NULL) {
               ast_free(fn);
               continue;   /* cannot open file */
            }
            s = get_filestream(f, bfile);
            if (!s) {
               fclose(bfile);
               ast_free(fn);  /* cannot allocate descriptor */
               continue;
            }
            if (open_wrapper(s)) {
               ast_free(fn);
               ast_closestream(s);
               continue;   /* cannot run open on file */
            }
            if (st.st_size == 0) {
               ast_log(LOG_WARNING, "File %s detected to have zero size.\n", fn);
            }
            /* ok this is good for OPEN */
            res = 1; /* found */
            s->lasttimeout = -1;
            s->fmt = f;
            s->trans = NULL;
            s->filename = NULL;
            if (AST_FORMAT_GET_TYPE(s->fmt->format.id) == AST_FORMAT_TYPE_AUDIO) {
               if (ast_channel_stream(chan))
                  ast_closestream(ast_channel_stream(chan));
               ast_channel_stream_set(chan, s);
            } else {
               if (ast_channel_vstream(chan))
                  ast_closestream(ast_channel_vstream(chan));
               ast_channel_vstream_set(chan, s);
            }
            ast_free(fn);
            break;
         }
         switch (action) {
         case ACTION_OPEN:
            break;   /* will never get here */

         case ACTION_EXISTS:  /* return the matching format */
            /* if arg2 is present, it is a format capabilities structure.
             * Add this format to the set of formats this file can be played in */
            if (arg2) {
               ast_format_cap_add((struct ast_format_cap *) arg2, &f->format);
            }
            res = 1; /* file does exist and format it exists in is returned in arg2 */
            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));
               ast_free(nfn);
            }
             }
            break;

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

static int is_absolute_path(const char *filename)
{
   return filename[0] == '/';
}

/*!
 * \brief test if a file exists for a given format.
 * \note result_cap is OPTIONAL
 * \retval 1, true and result_cap represents format capabilities file exists in.
 * \retval 0, false
 */
static int fileexists_test(const char *filename, const char *fmt, const char *lang,
            char *buf, int buflen, struct ast_format_cap *result_cap)
{
   if (buf == NULL) {
      return 0;
   }

   if (ast_language_is_prefix && !is_absolute_path(filename)) { /* new layout */
      if (lang) {
         snprintf(buf, buflen, "%s/%s", lang, filename);
      } else {
         snprintf(buf, buflen, "%s", filename);
      }
   } else { /* old layout */
      strcpy(buf, filename);  /* first copy the full string */
      if (lang) {
         /* insert the language and suffix if needed */
         const char *c = strrchr(filename, '/');
         int offset = c ? c - filename + 1 : 0; /* points right after the last '/' */
         snprintf(buf + offset, buflen - offset, "%s/%s", lang, filename + offset);
      }
   }

   return filehelper(buf, result_cap, fmt, ACTION_EXISTS);
}

/*!
 * \brief helper routine to locate a file with a given format
 * and language preference.
 *
 * \note Try preflang, preflang with stripped '_' suffices, or NULL.
 *
 * \note The last parameter(s) point to a buffer of sufficient size,
 * which on success is filled with the matching filename.
 *
 * \param filename, name of the file.
 * \param fmt, format to look for the file in. OPTIONAL
 * \param preflang, the perfered language
 * \param buf, returns the matching filename
 * \param buflen, size of the buf
 * \param result_cap, OPTIONAL format capabilities result structure
 *        returns what formats the file was found in.
 *
 * \retval 1, true. file exists and result format is set
 * \retval 0, false. file does not exist.
 */
static int fileexists_core(const char *filename, const char *fmt, const char *preflang,
            char *buf, int buflen, struct ast_format_cap *result_cap)
{
   char *lang;

   if (buf == NULL) {
      return 0;
   }

   /* We try languages in the following order:
    *    preflang (may include dialect and style codes)
    *    lang (preflang without dialect - if any)
    *    <none>
    *    default (unless the same as preflang or lang without dialect)
    */

   lang = ast_strdupa(preflang);

   /* Try preferred language, including removing any style or dialect codes */
   while (!ast_strlen_zero(lang)) {
      char *end;

      if (fileexists_test(filename, fmt, lang, buf, buflen, result_cap)) {
         return 1;
      }

      if ((end = strrchr(lang, '_')) != NULL) {
         *end = '\0';
         continue;
      }

      break;
   }

   /* Try without any language */
   if (fileexists_test(filename, fmt, NULL, buf, buflen, result_cap)) {
      return 1;
   }

   /* Finally try the default language unless it was already tried before */
   if ((ast_strlen_zero(preflang) || strcmp(preflang, DEFAULT_LANGUAGE)) && (ast_strlen_zero(lang) || strcmp(lang, DEFAULT_LANGUAGE))) {
      if ((fileexists_test(filename, fmt, DEFAULT_LANGUAGE, buf, buflen, result_cap)) > 0) {
         return 1;
      }
   }

   return 0;
}

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.
    */
   struct ast_format_cap *file_fmt_cap;
   int res;
   int buflen;
   char *buf;

   if (!asis) {
      /* do this first, otherwise we detect the wrong writeformat */
      ast_stopstream(chan);
      if (ast_channel_generator(chan))
         ast_deactivate_generator(chan);
   }
   if (preflang == NULL)
      preflang = "";
   buflen = strlen(preflang) + strlen(filename) + 4;
   buf = ast_alloca(buflen);

   if (!(file_fmt_cap = ast_format_cap_alloc_nolock())) {
      return NULL;
   }
   if (!fileexists_core(filename, NULL, preflang, buf, buflen, file_fmt_cap) ||
      !ast_format_cap_has_type(file_fmt_cap, AST_FORMAT_TYPE_AUDIO)) {

      ast_log(LOG_WARNING, "File %s does not exist in any format\n", filename);
      file_fmt_cap = ast_format_cap_destroy(file_fmt_cap);
      return NULL;
   }

   /* Set the channel to a format we can work with and save off the previous format. */
   ast_format_copy(ast_channel_oldwriteformat(chan), ast_channel_writeformat(chan));
   /* Set the channel to the best format that exists for the file. */
   res = ast_set_write_format_from_cap(chan, file_fmt_cap);
   /* don't need this anymore now that the channel's write format is set. */
   file_fmt_cap = ast_format_cap_destroy(file_fmt_cap);

   if (res == -1) {  /* No format available that works with this channel */
      return NULL;
   }
   res = filehelper(buf, chan, NULL, ACTION_OPEN);
   if (res >= 0)
      return ast_channel_stream(chan);
   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.
    */
   struct ast_format tmp_fmt;
   struct ast_format_cap *tmp_cap;
   char *buf;
   int buflen;
   const char *fmt;
   int fd;

   if (preflang == NULL)
      preflang = "";
   buflen = strlen(preflang) + strlen(filename) + 4;
   buf = ast_alloca(buflen);

   /* is the channel capable of video without translation ?*/
   if (!ast_format_cap_has_type(ast_channel_nativeformats(chan), AST_FORMAT_TYPE_VIDEO)) {
      return NULL;
   }
   if (!(tmp_cap = ast_format_cap_alloc_nolock())) {
      return NULL;
   }
   /* Video is supported, so see what video formats exist for this file */
   if (!fileexists_core(filename, NULL, preflang, buf, buflen, tmp_cap)) {
      tmp_cap = ast_format_cap_destroy(tmp_cap);
      return NULL;
   }

   /* iterate over file formats and pick the first one compatible with the channel's native formats */
   ast_format_cap_iter_start(tmp_cap);
   while (!ast_format_cap_iter_next(tmp_cap, &tmp_fmt)) {
      fmt = ast_getformatname(&tmp_fmt);
      if ((AST_FORMAT_GET_TYPE(tmp_fmt.id) != AST_FORMAT_TYPE_VIDEO) ||
         !ast_format_cap_iscompatible(ast_channel_nativeformats(chan), &tmp_fmt)) {
         continue;
      }

      fd = filehelper(buf, chan, fmt, ACTION_OPEN);
      if (fd >= 0) {
         ast_format_cap_iter_end(tmp_cap);
         tmp_cap = ast_format_cap_destroy(tmp_cap);
         return ast_channel_vstream(chan);
      }
      ast_log(LOG_WARNING, "File %s has video but couldn't be opened\n", filename);
   }
   ast_format_cap_iter_end(tmp_cap);
   tmp_cap = ast_format_cap_destroy(tmp_cap);

   return NULL;
}

static struct ast_frame *read_frame(struct ast_filestream *s, int *whennext)
{
   struct ast_frame *fr, *new_fr;

   if (!s || !s->fmt) {
      return NULL;
   }

   if (!(fr = s->fmt->read(s, whennext))) {
      return NULL;
   }

   if (!(new_fr = ast_frisolate(fr))) {
      ast_frfree(fr);
      return NULL;
   }

   if (new_fr != fr) {
      ast_frfree(fr);
      fr = new_fr;
   }

   return fr;
}

struct ast_frame *ast_readframe(struct ast_filestream *s)
{
   int whennext = 0;

   return read_frame(s, &whennext);
}

enum fsread_res {
   FSREAD_FAILURE,
   FSREAD_SUCCESS_SCHED,
   FSREAD_SUCCESS_NOSCHED,
};

static int ast_fsread_audio(const void *data);

static enum fsread_res ast_readaudio_callback(struct ast_filestream *s)
{
   int whennext = 0;

   while (!whennext) {
      struct ast_frame *fr;

      if (s->orig_chan_name && strcasecmp(ast_channel_name(s->owner), s->orig_chan_name)) {
         goto return_failure;
      }

      fr = read_frame(s, &whennext);

      if (!fr /* stream complete */ || ast_write(s->owner, fr) /* error writing */) {
         if (fr) {
            ast_log(LOG_WARNING, "Failed to write frame\n");
            ast_frfree(fr);
         }
         goto return_failure;
      }

      if (fr) {
         ast_frfree(fr);
      }
   }

   if (whennext != s->lasttimeout) {
      if (ast_channel_timingfd(s->owner) > -1) {
         float samp_rate = (float) ast_format_rate(&s->fmt->format);
         unsigned int rate;

         rate = (unsigned int) roundf(samp_rate / ((float) whennext));

         ast_settimeout_full(s->owner, rate, ast_fsread_audio, s, 1);
      } else {
         ast_channel_streamid_set(s->owner, ast_sched_add(ast_channel_sched(s->owner), whennext / (ast_format_rate(&s->fmt->format) / 1000), ast_fsread_audio, s));
      }
      s->lasttimeout = whennext;
      return FSREAD_SUCCESS_NOSCHED;
   }
   return FSREAD_SUCCESS_SCHED;

return_failure:
   ast_channel_streamid_set(s->owner, -1);
   ast_settimeout(s->owner, 0, NULL, NULL);
   return FSREAD_FAILURE;
}

static int ast_fsread_audio(const void *data)
{
   struct ast_filestream *fs = (struct ast_filestream *)data;
   enum fsread_res res;

   res = ast_readaudio_callback(fs);

   if (res == FSREAD_SUCCESS_SCHED)
      return 1;

   return 0;
}

static int ast_fsread_video(const void *data);

static enum fsread_res ast_readvideo_callback(struct ast_filestream *s)
{
   int whennext = 0;

   while (!whennext) {
      struct ast_frame *fr = read_frame(s, &whennext);

      if (!fr /* stream complete */ || ast_write(s->owner, fr) /* error writing */) {
         if (fr) {
            ast_log(LOG_WARNING, "Failed to write frame\n");
            ast_frfree(fr);
         }
         ast_channel_vstreamid_set(s->owner, -1);
         return FSREAD_FAILURE;
      }

      if (fr) {
         ast_frfree(fr);
      }
   }

   if (whennext != s->lasttimeout) {
      ast_channel_vstreamid_set(s->owner, ast_sched_add(ast_channel_sched(s->owner), whennext / (ast_format_rate(&s->fmt->format) / 1000), ast_fsread_video, s));
      s->lasttimeout = whennext;
      return FSREAD_SUCCESS_NOSCHED;
   }

   return FSREAD_SUCCESS_SCHED;
}

static int ast_fsread_video(const void *data)
{
   struct ast_filestream *fs = (struct ast_filestream *)data;
   enum fsread_res res;

   res = ast_readvideo_callback(fs);

   if (res == FSREAD_SUCCESS_SCHED)
      return 1;

   return 0;
}

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

int ast_playstream(struct ast_filestream *s)
{
   enum fsread_res res;

   if (AST_FORMAT_GET_TYPE(s->fmt->format.id) == AST_FORMAT_TYPE_AUDIO)
      res = ast_readaudio_callback(s);
   else
      res = ast_readvideo_callback(s);

   return (res == FSREAD_FAILURE) ? -1 : 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)
{
   /* This used to destroy the filestream, but it now just decrements a refcount.
    * We close the stream in order to quit queuing frames now, because we might
    * change the writeformat, which could result in a subsequent write error, if
    * the format is different. */
   filestream_close(f);
   ao2_ref(f, -1);
   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) + 4;  /* room for everything */
   buf = ast_alloca(buflen);
   return fileexists_core(filename, fmt, preflang, buf, buflen, NULL) ? 1 : 0;
}

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

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

int ast_filecopy(const char *filename, const char *filename2, const char *fmt)
{
   return 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];
   off_t pos;
   int seekattempt;
   int res;

   fs = ast_openstream(chan, filename, preflang);
   if (!fs) {
      ast_log(LOG_WARNING, "Unable to open %s (format %s): %s\n", filename, ast_getformatname_multiple(fmt, sizeof(fmt), ast_channel_nativeformats(chan)), strerror(errno));
      return -1;
   }

   /* check to see if there is any data present (not a zero length file),
    * done this way because there is no where for ast_openstream_full to
    * return the file had no data. */
   pos = ftello(fs->f);
   seekattempt = fseeko(fs->f, -1, SEEK_END);
   if (seekattempt) {
      if (errno == EINVAL) {
         /* Zero-length file, as opposed to a pipe */
         return 0;
      } else {
         ast_seekstream(fs, 0, SEEK_SET);
      }
   } else {
      fseeko(fs->f, pos, SEEK_SET);
   }

   vfs = ast_openvstream(chan, filename, preflang);
   if (vfs) {
      ast_debug(1, "Ooh, found a video stream, too, format %s\n", ast_getformatname(&vfs->fmt->format));
   }

   if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_MASQ_NOSTREAM))
      fs->orig_chan_name = ast_strdup(ast_channel_name(chan));
   if (ast_applystream(chan, fs))
      return -1;
   if (vfs && ast_applystream(chan, vfs))
      return -1;
   res = ast_playstream(fs);
   if (!res && vfs)
      res = ast_playstream(vfs);
   ast_verb(3, "<%s> Playing '%s.%s' (language '%s')\n", ast_channel_name(chan), filename, ast_getformatname(ast_channel_writeformat(chan)), preflang ? preflang : "default");

   return res;
}

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_def *f;
   struct ast_filestream *fs = NULL;
   char *fn;
   int format_found = 0;

   AST_RWLIST_RDLOCK(&formats);

   AST_RWLIST_TRAVERSE(&formats, f, list) {
      fs = NULL;
      if (!exts_compare(f->exts, type))
         continue;
      else
         format_found = 1;

      fn = build_filename(filename, type);
      if (!fn) {
         continue;
      }
      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_closestream(fs);
         }
         fs = NULL;
         bfile = NULL;
         ast_free(fn);
         break;
      }
      /* found it */
      fs->trans = NULL;
      fs->fmt = f;
      fs->flags = flags;
      fs->mode = mode;
      fs->filename = ast_strdup(filename);
      fs->vfs = NULL;
      ast_free(fn);
      break;
   }

   AST_RWLIST_UNLOCK(&formats);
   if (!format_found)
      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_def *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);
      if (!fn) {
         continue;
      }
      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 = ast_alloca(size);
         strcpy(buf, record_cache_dir);
         strcat(buf, "/");
         strcat(buf, fn);
         ast_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) {
            if ((fs->write_buffer = ast_malloc(32768))) {
               setvbuf(fs->f, fs->write_buffer, _IOFBF, 32768);
            }
         }
         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_closestream(fs);
               fs = NULL;
            }
            if (!buf) {
               ast_free(fn);
            }
            continue;
         }
         fs->trans = NULL;
         fs->fmt = f;
         fs->flags = flags;
         fs->mode = mode;
         if (orig_fn) {
            fs->realfilename = ast_strdup(orig_fn);
            fs->filename = ast_strdup(fn);
         } else {
            fs->realfilename = NULL;
            fs->filename = ast_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)
         ast_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 *reverse,
   int skip_ms,
   int audiofd,
   int cmdfd,
   const char *context,
   ast_waitstream_fr_cb cb)
{
   const char *orig_chan_name = NULL;

   int err = 0;

   if (!breakon)
      breakon = "";
   if (!forward)
      forward = "";
   if (!reverse)
      reverse = "";

   /* Switch the channel to end DTMF frame only. waitstream_core doesn't care about the start of DTMF. */
   ast_set_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);

   if (ast_test_flag(ast_channel_flags(c), AST_FLAG_MASQ_NOSTREAM))
      orig_chan_name = ast_strdupa(ast_channel_name(c));

   if (ast_channel_stream(c) && cb) {
      long ms_len = ast_tellstream(ast_channel_stream(c)) / (ast_format_rate(&ast_channel_stream(c)->fmt->format) / 1000);
      cb(c, ms_len, AST_WAITSTREAM_CB_START);
   }

   while (ast_channel_stream(c)) {
      int res;
      int ms;

      if (orig_chan_name && strcasecmp(orig_chan_name, ast_channel_name(c))) {
         ast_stopstream(c);
         err = 1;
         break;
      }

      ms = ast_sched_wait(ast_channel_sched(c));

      if (ms < 0 && !ast_channel_timingfunc(c)) {
         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));
            ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
            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));
            ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
            return -1;
         } else if (outfd > -1) { /* this requires cmdfd set */
            /* The FD we were watching has something waiting */
            ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
            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) {
            ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
            return -1;
         }
         switch (fr->frametype) {
         case AST_FRAME_DTMF_END:
            if (context) {
               const char exten[2] = { fr->subclass.integer, '\0' };
               if (ast_exists_extension(c, context, exten, 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  res = fr->subclass.integer;
                  ast_frfree(fr);
                  ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                  return res;
               }
            } else {
               enum ast_waitstream_fr_cb_values cb_val = 0;
               res = fr->subclass.integer;
               if (strchr(forward, res)) {
                  int eoftest;
                  ast_stream_fastforward(ast_channel_stream(c), skip_ms);
                  eoftest = fgetc(ast_channel_stream(c)->f);
                  if (feof(ast_channel_stream(c)->f)) {
                     ast_stream_rewind(ast_channel_stream(c), skip_ms);
                  } else {
                     ungetc(eoftest, ast_channel_stream(c)->f);
                  }
                  cb_val = AST_WAITSTREAM_CB_FASTFORWARD;
               } else if (strchr(reverse, res)) {
                  ast_stream_rewind(ast_channel_stream(c), skip_ms);
                  cb_val = AST_WAITSTREAM_CB_REWIND;
               } else if (strchr(breakon, res)) {
                  ast_frfree(fr);
                  ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
                  return res;
               }
               if (cb_val && cb) {
                  long ms_len = ast_tellstream(ast_channel_stream(c)) / (ast_format_rate(&ast_channel_stream(c)->fmt->format) / 1000);
                  cb(c, ms_len, cb_val);
               }
            }
            break;
         case AST_FRAME_CONTROL:
            switch (fr->subclass.integer) {
            case AST_CONTROL_HANGUP:
            case AST_CONTROL_BUSY:
            case AST_CONTROL_CONGESTION:
               ast_frfree(fr);
               ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
               return -1;
            case AST_CONTROL_RINGING:
            case AST_CONTROL_ANSWER:
            case AST_CONTROL_VIDUPDATE:
            case AST_CONTROL_SRCUPDATE:
            case AST_CONTROL_SRCCHANGE:
            case AST_CONTROL_HOLD:
            case AST_CONTROL_UNHOLD:
            case AST_CONTROL_CONNECTED_LINE:
            case AST_CONTROL_REDIRECTING:
            case AST_CONTROL_AOC:
            case AST_CONTROL_UPDATE_RTP_PEER:
            case AST_CONTROL_PVT_CAUSE_CODE:
            case -1:
               /* Unimportant */
               break;
            default:
               ast_log(LOG_WARNING, "Unexpected control subclass '%d'\n", fr->subclass.integer);
            }
            break;
         case AST_FRAME_VOICE:
            /* Write audio if appropriate */
            if (audiofd > -1) {
               if (write(audiofd, fr->data.ptr, fr->datalen) < 0) {
                  ast_log(LOG_WARNING, "write() failed: %s\n", strerror(errno));
               }
            }
         default:
            /* Ignore all others */
            break;
         }
         ast_frfree(fr);
      }
      ast_sched_runq(ast_channel_sched(c));
   }

   ast_clear_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);

   return (err || ast_channel_softhangup_internal_flag(c)) ? -1 : 0;
}

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

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

int ast_waitstream(struct ast_channel *c, const char *breakon)
{
   return waitstream_core(c, breakon, NULL, NULL, 0, -1, -1, NULL, NULL /* no callback */);
}

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 */, NULL /* no callback */);
}

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 = ast_channel_context(c);
   return waitstream_core(c, NULL, NULL, NULL, 0,
      -1, -1, context, NULL /* no callback */);
}

/*
 * 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 *digits)
{
   int res = 0;
   if (!ast_strlen_zero(file)) {
      ast_test_suite_event_notify("PLAYBACK", "Message: %s\r\nChannel: %s", file, ast_channel_name(chan));
      res = ast_streamfile(chan, file, ast_channel_language(chan));
      if (!res) {
         res = ast_waitstream(chan, digits);
      }
   }
   return res;
}

char *ast_format_str_reduce(char *fmts)
{
   struct ast_format_def *f;
   struct ast_format_def *fmts_ptr[AST_MAX_FORMATS];
   char *fmts_str[AST_MAX_FORMATS];
   char *stringp, *type;
   char *orig = fmts;
   int i, j, x, first, found = 0;
   int len = strlen(fmts) + 1;
   int res;

   if (AST_RWLIST_RDLOCK(&formats)) {
      ast_log(LOG_WARNING, "Unable to lock format list\n");
      return NULL;
   }

   stringp = ast_strdupa(fmts);

   for (x = 0; (type = strsep(&stringp, "|")) && x < AST_MAX_FORMATS; x++) {
      AST_RWLIST_TRAVERSE(&formats, f, list) {
         if (exts_compare(f->exts, type)) {
            found = 1;
            break;
         }
      }

      fmts_str[x] = type;
      if (found) {
         fmts_ptr[x] = f;
      } else {
         fmts_ptr[x] = NULL;
      }
   }
   AST_RWLIST_UNLOCK(&formats);

   first = 1;
   for (i = 0; i < x; i++) {
      /* ignore invalid entries */
      if (!fmts_ptr[i]) {
         ast_log(LOG_WARNING, "ignoring unknown format '%s'\n", fmts_str[i]);
         continue;
      }

      /* special handling for the first entry */
      if (first) {
         res = snprintf(fmts, len, "%s", fmts_str[i]);
         fmts += res;
         len -= res;
         first = 0;
         continue;
      }

      found = 0;
      for (j = 0; j < i; j++) {
         /* this is a duplicate */
         if (fmts_ptr[j] == fmts_ptr[i]) {
            found = 1;
            break;
         }
      }

      if (!found) {
         res = snprintf(fmts, len, "|%s", fmts_str[i]);
         fmts += res;
         len -= res;
      }
   }

   if (first) {
      ast_log(LOG_WARNING, "no known formats found in format list (%s)\n", orig);
      return NULL;
   }

   return orig;
}

static char *handle_cli_core_show_file_formats(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
#define FORMAT "%-10s %-10s %-20s\n"
#define FORMAT2 "%-10s %-10s %-20s\n"
   struct ast_format_def *f;
   int count_fmt = 0;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show file formats";
      e->usage =
         "Usage: core show file formats\n"
         "       Displays currently registered file formats (if any).\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 4)
      return CLI_SHOWUSAGE;

   ast_cli(a->fd, FORMAT, "Format", "Name", "Extensions");
   ast_cli(a->fd, FORMAT, "------", "----", "----------");

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

static struct ast_cli_entry cli_file[] = {
   AST_CLI_DEFINE(handle_cli_core_show_file_formats, "Displays file formats")
};

static void file_shutdown(void)
{
   ast_cli_unregister_multiple(cli_file, ARRAY_LEN(cli_file));
}

int ast_file_init(void)
{
   ast_cli_register_multiple(cli_file, ARRAY_LEN(cli_file));
   ast_register_atexit(file_shutdown);
   return 0;
}