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