filter_common.c

   1 /*
   2  * Copyright (C) 2005-2009 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 <regex.h>
  10 #include <sys/types.h>
  11 #include <dirent.h>
  12 #include <stdbool.h>
  13
  14 #include "para.h"
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "fd.h"
  18 #include "ggo.h"
  19 #include "buffer_tree.h"
  20 #include "filter.h"
  21 #include "error.h"
  22 #include "string.h"
  23
  24 /** The array of supported filters. */
  25 struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
  26
  27 /**
  28  * Call the init function of each supported filter.
  29  * \sa filter::init
  30  */
  31 void filter_init(void)
  32 {
  33         int i;
  34
  35         FOR_EACH_SUPPORTED_FILTER(i)
  36                 filters[i].init(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\n", fcb);
  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  * registered 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_post_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->inbufp;
 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                         t->error = f->convert(ib, *loaded, fn);
 132                         if (t->error < 0)
 133                                 return;
 134                         size = t->error;
 135                         call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
 136                                 fn->loaded - old_fn_loaded);
 137                         *loaded -= size;
 138                         conv += size + fn->loaded - old_fn_loaded;
 139                         if (*loaded && size)
 140                                 memmove(ib, ib + size, *loaded);
 141                 }
 142                 ib = fn->buf;
 143                 loaded = &fn->loaded;
 144         }
 145         conv_total += conv;
 146         if (conv)
 147                 goto again;
 148         if (*fc->input_error >= 0)
 149                 return;
 150         if (*fc->out_loaded)
 151                 return;
 152         if (*fc->in_loaded && conv_total)
 153                 return;
 154         t->error = -E_FC_EOF;
 155 }
 156
 157 /**
 158  * Close all filter nodes and their callbacks.
 159  *
 160  * \param fc The filter chain to close.
 161  *
 162  * For each filter node determined by \a fc, call the close function of each
 163  * registered filter callback as well as the close function of the
 164  * corresponding filter.  Free all resources and destroy all callback lists and
 165  * the filter node list.
 166  *
 167  * \sa filter::close, filter_callback::close
 168  */
 169 void close_filters(struct filter_chain *fc)
 170 {
 171         struct filter_node *fn;
 172         int i;
 173
 174         if (!fc)
 175                 return;
 176         PARA_NOTICE_LOG("closing filter chain %p\n", fc);
 177         FOR_EACH_FILTER_NODE(fn, fc, i) {
 178                 struct filter *f = filters + fn->filter_num;
 179                 close_callbacks(fn);
 180                 PARA_INFO_LOG("closing %s filter\n", f->name);
 181                 f->close(fn);
 182         }
 183         free(fc->filter_nodes);
 184 }
 185
 186 /*
 187  * If the filter has a command line parser and options is not NULL, run it.
 188  * Returns filter_num on success, negative on errors
 189  */
 190 static int parse_filter_args(int filter_num, char *options, void **conf)
 191 {
 192         struct filter *f = &filters[filter_num];
 193         int ret, i, argc = 2;
 194         char **argv;
 195
 196 //      PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
 197 //              options? options : "(none)", f->parse_config);
 198         if (!f->parse_config)
 199                 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
 200 //      PARA_DEBUG_LOG("options: %s\n", options);
 201         argc = create_argv(options, " \t", &argv);
 202         if (argc < 0)
 203                 return -E_BAD_FILTER_OPTIONS;
 204         PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
 205         for (i = argc - 1; i >= 0; i--)
 206                 argv[i + 1] = argv[i];
 207         argv[0] = para_strdup(f->name);
 208         argc++;
 209         ret = f->parse_config(argc, argv, conf);
 210         free(argv[argc - 1]);
 211         argv[argc - 1] = NULL;
 212         free_argv(argv);
 213         return ret < 0? ret : filter_num;
 214 }
 215
 216 /**
 217  * Check the filter command line options.
 218  *
 219  * \param fa The command line options.
 220  * \param conf Points to the filter configuration upon successful return.
 221  *
 222  * Check if \a fa starts with a the name of a supported filter, followed by
 223  * a colon. If yes, call the command line parser of that filter.
 224  *
 225  * \return On success, the number of the filter is returned and \a conf
 226  * is initialized to point to the filter configuration determined by \a fa.
 227  * On errors, a negative value is returned.
 228  *
 229  * Note: If \a fa specifies a filter that has no command line parser success is
 230  * returned, and \a conf is initialized to \p NULL.
 231  *
 232  * \sa filter::parse_config
 233  */
 234 int check_filter_arg(char *fa, void **conf)
 235 {
 236         int j;
 237
 238         *conf = NULL;
 239 //      PARA_DEBUG_LOG("arg: %s\n", fa);
 240         FOR_EACH_SUPPORTED_FILTER(j) {
 241                 const char *name = filters[j].name;
 242                 size_t len = strlen(name);
 243                 char c;
 244                 if (strlen(fa) < len)
 245                         continue;
 246                 if (strncmp(name, fa, len))
 247                         continue;
 248                 c = fa[len];
 249                 if (c && c != ' ')
 250                         continue;
 251                 if (c && !filters[j].parse_config)
 252                         return -E_BAD_FILTER_OPTIONS;
 253                 return parse_filter_args(j, c? fa + len + 1 :
 254                         fa + strlen(fa), conf);
 255         }
 256         return -E_UNSUPPORTED_FILTER;
 257 }
 258
 259 void print_filter_helps(int detailed)
 260 {
 261         int i;
 262
 263         printf_or_die("\nAvailable filters: \n\t");
 264         FOR_EACH_SUPPORTED_FILTER(i)
 265                 printf_or_die("%s%s", i? " " : "", filters[i].name);
 266         printf_or_die("\n\n");
 267
 268         FOR_EACH_SUPPORTED_FILTER(i) {
 269                 struct filter *f = filters + i;
 270
 271                 if (!f->help.short_help)
 272                         continue;
 273                 printf_or_die("Options for %s:\n", f->name);
 274                 ggo_print_help(&f->help, detailed);
 275         }
 276
 277 }
 278
 279 /** 640K ought to be enough for everybody ;) */
 280 #define FILTER_MAX_PENDING (640 * 1024)
 281
 282 int prepare_filter_node(struct filter_node *fn)
 283 {
 284         struct btr_node *btrn = fn->btrn;
 285         size_t iqs;
 286
 287         if (btr_eof(btrn))
 288                 return -E_FC_EOF;
 289         if (btr_bytes_pending(btrn) > FILTER_MAX_PENDING)
 290                 return 0;
 291         iqs = btr_get_input_queue_size(btrn);
 292         if (iqs < fn->min_iqs && !btr_no_parent(btrn))
 293                 return 0;
 294         assert(iqs != 0);
 295         /* avoid "buffer too small" errors from the decoder */
 296         btr_merge(btrn, fn->min_iqs);
 297         return 1;
 298 }
 299
 300 void generic_filter_pre_select(struct sched *s, struct task *t)
 301 {
 302         struct filter_node *fn = container_of(t, struct filter_node, task);
 303         size_t iqs = btr_get_input_queue_size(fn->btrn);
 304
 305         t->error = 0;
 306         if (iqs < fn->min_iqs)
 307                 return;
 308         if (btr_bytes_pending(fn->btrn) > FILTER_MAX_PENDING)
 309                 return; /* FIXME, should use reasonable bound on timeout */
 310         s->timeout.tv_sec = 0;
 311         s->timeout.tv_usec = 1;
 312 }
 313