filter_common.c

   1 /*
   2  * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file filter_common.c Common helper functions for filter input/output. */
   8
   9 #include <sys/types.h>
  10 #include <dirent.h>
  11
  12 #include "para.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "fd.h"
  16 #include "ggo.h"
  17 #include "filter.h"
  18 #include "error.h"
  19 #include "string.h"
  20
  21 /** The array of supported filters. */
  22 struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
  23
  24 /**
  25  * Call the init function of each supported filter.
  26  *
  27  * \param all_filters the array of all supported filters.
  28  *
  29  * \sa filter::init
  30  */
  31 void filter_init(struct filter *all_filters)
  32 {
  33         int i;
  34
  35         FOR_EACH_SUPPORTED_FILTER(i)
  36                 all_filters[i].init(all_filters + i);
  37 }
  38
  39 /**
  40  * Close and destroy a filter callback.
  41  *
  42  * \param fcb The filter callback to close.
  43  *
  44  * This removes \a fcb from the list of filter callbacks and calls
  45  * the close callback associated with \a fcb.
  46  */
  47 static void close_filter_callback(struct filter_callback *fcb)
  48 {
  49         PARA_NOTICE_LOG("closing filter_callback %p, data: %p\n", fcb, fcb->data);
  50         list_del(&fcb->node);
  51         fcb->close(fcb);
  52 }
  53
  54 /**
  55  * Close all callbacks of a filter node.
  56  *
  57  * \param fn The filter node which contains the filter callbacks to be closed.
  58  *
  59  * Call close_filter_callback() for each entry in the filter callback list
  60  * of \a fn.
  61  */
  62 static void close_callbacks(struct filter_node *fn)
  63 {
  64         struct filter_callback *fcb, *tmp;
  65
  66         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  67                 PARA_INFO_LOG("closing %s filter callback\n",
  68                         filters[fn->filter_num].name);
  69                 close_filter_callback(fcb);
  70         }
  71 }
  72
  73 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
  74         char *outbuf, size_t outlen)
  75 {
  76         struct filter_callback *fcb, *tmp;
  77         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  78                 int ret;
  79                 if (inlen && fcb->input_cb) {
  80                         ret = fcb->input_cb(inbuf, inlen, fcb);
  81                         if (ret < 0) {
  82                                 close_filter_callback(fcb);
  83                                 continue;
  84                         }
  85                 }
  86                 if (!outlen || !fcb->output_cb)
  87                         continue;
  88                 ret = fcb->output_cb(outbuf, outlen, fcb);
  89                 if (ret < 0)
  90                         close_filter_callback(fcb);
  91         }
  92 }
  93
  94 /**
  95  * Call the convert function of each filter.
  96  *
  97  * \param s Unused.
  98  * \param t The task identifying the filter chain.
  99  *
 100  * This is the core function of the filter subsystem. It loops over the list of
 101  * filter nodes determined by \a t and calls the filter's convert function if
 102  * there is input available for the filter node in question. If the convert
 103  * function consumed some or all of its input data, all registered input
 104  * callbacks are called.  Similarly, if a convert function produced output, all
 105  * registerd output callbacks get called.
 106  *
 107  * On errors a (negative) error code is stored in t->error.
 108  *
 109  * \sa filter_node, filter#convert, filter_callback.
 110  */
 111 void filter_pre_select(__a_unused struct sched *s, struct task *t)
 112 {
 113         struct filter_chain *fc = container_of(t, struct filter_chain, task);
 114         struct filter_node *fn;
 115         char *ib;
 116         size_t *loaded;
 117         int i, conv, conv_total = 0;
 118
 119         if (fc->output_error && *fc->output_error < 0) {
 120                 t->error =  *fc->output_error;
 121                 return;
 122         }
 123 again:
 124         ib = fc->inbuf;
 125         loaded = fc->in_loaded;
 126         conv = 0;
 127         FOR_EACH_FILTER_NODE(fn, fc, i) {
 128                 struct filter *f = filters + fn->filter_num;
 129                 if (fn->loaded < fn->bufsize) {
 130                         size_t size, old_fn_loaded = fn->loaded;
 131 //                      PARA_DEBUG_LOG("fc %p loaded: %zd, calling %s convert\n",
 132 //                              fc, *loaded, fn->filter->name);
 133                         t->error = f->convert(ib, *loaded, fn);
 134                         if (t->error < 0)
 135                                 return;
 136                         size = t->error;
 137                         call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
 138                                 fn->loaded - old_fn_loaded);
 139                         *loaded -= size;
 140                         conv += size;
 141                         if (*loaded && size) {
 142 //                              PARA_DEBUG_LOG("moving %zd bytes in input "
 143 //                                      "buffer for %s filter\n",
 144 //                                      *loaded,  fn->filter->name);
 145                                 memmove(ib, ib + size, *loaded);
 146                         }
 147                 }
 148                 ib = fn->buf;
 149                 loaded = &fn->loaded;
 150         }
 151         conv_total += conv;
 152 //      PARA_DEBUG_LOG("eof (in/out/fc): %d/%d/%d out_loaded: %zd, "
 153 //              "conv: %d, conv_total: %d\n", *fc->input_eof,
 154 //              fc->output_eof? *fc->output_eof : -42,
 155 //              fc->eof, *fc->out_loaded, conv, conv_total);
 156         if (conv)
 157                 goto again;
 158         if (!*fc->input_error)
 159                 return;
 160         if (*fc->out_loaded)
 161                 return;
 162         if (*fc->in_loaded && conv_total)
 163                 return;
 164         t->error = -E_FC_EOF;
 165 }
 166
 167 /**
 168  * Close all filter nodes and their callbacks.
 169  *
 170  * \param fc The filter chain to close.
 171  *
 172  * For each filter node determined by \a fc, call the close function of each
 173  * registered filter callback as well as the close function of the
 174  * corresponding filter.  Free all resources and destroy all callback lists and
 175  * the filter node list.
 176  *
 177  * \sa filter::close, filter_callback::close
 178  */
 179 void close_filters(struct filter_chain *fc)
 180 {
 181         struct filter_node *fn;
 182         int i;
 183
 184         if (!fc)
 185                 return;
 186         PARA_NOTICE_LOG("closing filter chain %p\n", fc);
 187         FOR_EACH_FILTER_NODE(fn, fc, i) {
 188                 struct filter *f = filters + fn->filter_num;
 189                 close_callbacks(fn);
 190                 PARA_INFO_LOG("closing %s filter\n", f->name);
 191                 f->close(fn);
 192         }
 193         free(fc->filter_nodes);
 194 }
 195
 196 /*
 197  * If the filter has a command line parser and options is not NULL, run it.
 198  * Returns filter_num on success, negative on errors
 199  */
 200 static int parse_filter_args(int filter_num, char *options, void **conf)
 201 {
 202         struct filter *f = &filters[filter_num];
 203         int ret, i, argc = 2;
 204         char **argv;
 205
 206 //      PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
 207 //              options? options : "(none)", f->parse_config);
 208         if (!f->parse_config)
 209                 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
 210 //      PARA_DEBUG_LOG("options: %s\n", options);
 211         argc = split_args(options, &argv, " \t");
 212 //              PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
 213         for (i = argc - 1; i >= 0; i--)
 214                 argv[i + 1] = argv[i];
 215         argv[0] = para_strdup(f->name);
 216         argc += 1;
 217         ret = f->parse_config(argc, argv, conf);
 218         free(argv[0]);
 219         free(argv);
 220         return ret < 0? ret : filter_num;
 221 }
 222
 223 /**
 224  * Check the filter command line options.
 225  *
 226  * \param fa The command line options.
 227  * \param conf Points to the filter configuration upon successful return.
 228  *
 229  * Check if \a fa starts with a the name of a supported filter, followed by
 230  * a colon. If yes, call the command line parser of that filter.
 231  *
 232  * \return On success, the number of the filter is returned and \a conf
 233  * is initialized to point to the filter configuration determined by \a fa.
 234  * On errors, a negative value is returned.
 235  *
 236  * Note: If \a fa specifies a filter that has no command line parser success is
 237  * returned, and \a conf is initialized to \p NULL.
 238  *
 239  * \sa filter::parse_config
 240  */
 241 int check_filter_arg(char *fa, void **conf)
 242 {
 243         int j;
 244
 245         *conf = NULL;
 246 //      PARA_DEBUG_LOG("arg: %s\n", fa);
 247         FOR_EACH_SUPPORTED_FILTER(j) {
 248                 const char *name = filters[j].name;
 249                 size_t len = strlen(name);
 250                 char c;
 251                 if (strlen(fa) < len)
 252                         continue;
 253                 if (strncmp(name, fa, len))
 254                         continue;
 255                 c = fa[len];
 256                 if (c && c != ' ')
 257                         continue;
 258                 if (c && !filters[j].parse_config)
 259                         return -E_BAD_FILTER_OPTIONS;
 260                 return parse_filter_args(j, c? fa + len + 1 :
 261                         fa + strlen(fa), conf);
 262         }
 263         return -E_UNSUPPORTED_FILTER;
 264 }
 265