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
  13 #include "para.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "fd.h"
  17 #include "ggo.h"
  18 #include "filter.h"
  19 #include "error.h"
  20 #include "string.h"
  21
  22 /** The array of supported filters. */
  23 struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
  24
  25 /**
  26  * Call the init function of each supported filter.
  27  * \sa filter::init
  28  */
  29 void filter_init(void)
  30 {
  31         int i;
  32
  33         FOR_EACH_SUPPORTED_FILTER(i)
  34                 filters[i].init(filters + i);
  35 }
  36
  37 /**
  38  * Close and destroy a filter callback.
  39  *
  40  * \param fcb The filter callback to close.
  41  *
  42  * This removes \a fcb from the list of filter callbacks and calls
  43  * the close callback associated with \a fcb.
  44  */
  45 static void close_filter_callback(struct filter_callback *fcb)
  46 {
  47         PARA_NOTICE_LOG("closing filter_callback %p\n", fcb);
  48         list_del(&fcb->node);
  49         fcb->close(fcb);
  50 }
  51
  52 /**
  53  * Close all callbacks of a filter node.
  54  *
  55  * \param fn The filter node which contains the filter callbacks to be closed.
  56  *
  57  * Call close_filter_callback() for each entry in the filter callback list
  58  * of \a fn.
  59  */
  60 static void close_callbacks(struct filter_node *fn)
  61 {
  62         struct filter_callback *fcb, *tmp;
  63
  64         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  65                 PARA_INFO_LOG("closing %s filter callback\n",
  66                         filters[fn->filter_num].name);
  67                 close_filter_callback(fcb);
  68         }
  69 }
  70
  71 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
  72         char *outbuf, size_t outlen)
  73 {
  74         struct filter_callback *fcb, *tmp;
  75         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  76                 int ret;
  77                 if (inlen && fcb->input_cb) {
  78                         ret = fcb->input_cb(inbuf, inlen, fcb);
  79                         if (ret < 0) {
  80                                 close_filter_callback(fcb);
  81                                 continue;
  82                         }
  83                 }
  84                 if (!outlen || !fcb->output_cb)
  85                         continue;
  86                 ret = fcb->output_cb(outbuf, outlen, fcb);
  87                 if (ret < 0)
  88                         close_filter_callback(fcb);
  89         }
  90 }
  91
  92 /**
  93  * Call the convert function of each filter.
  94  *
  95  * \param s Unused.
  96  * \param t The task identifying the filter chain.
  97  *
  98  * This is the core function of the filter subsystem. It loops over the list of
  99  * filter nodes determined by \a t and calls the filter's convert function if
 100  * there is input available for the filter node in question. If the convert
 101  * function consumed some or all of its input data, all registered input
 102  * callbacks are called.  Similarly, if a convert function produced output, all
 103  * registered output callbacks get called.
 104  *
 105  * On errors a (negative) error code is stored in t->error.
 106  *
 107  * \sa filter_node, filter#convert, filter_callback.
 108  */
 109 void filter_pre_select(__a_unused struct sched *s, struct task *t)
 110 {
 111         struct filter_chain *fc = container_of(t, struct filter_chain, task);
 112         struct filter_node *fn;
 113         char *ib;
 114         size_t *loaded;
 115         int i, conv, conv_total = 0;
 116
 117         if (fc->output_error && *fc->output_error < 0) {
 118                 t->error =  *fc->output_error;
 119                 return;
 120         }
 121 again:
 122         ib = *fc->inbufp;
 123         loaded = fc->in_loaded;
 124         conv = 0;
 125         FOR_EACH_FILTER_NODE(fn, fc, i) {
 126                 struct filter *f = filters + fn->filter_num;
 127                 if (fn->loaded < fn->bufsize) {
 128                         size_t size, old_fn_loaded = fn->loaded;
 129                         t->error = f->convert(ib, *loaded, fn);
 130                         if (t->error < 0)
 131                                 return;
 132                         size = t->error;
 133                         call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
 134                                 fn->loaded - old_fn_loaded);
 135                         *loaded -= size;
 136                         conv += size + fn->loaded - old_fn_loaded;
 137                         if (*loaded && size)
 138                                 memmove(ib, ib + size, *loaded);
 139                 }
 140                 ib = fn->buf;
 141                 loaded = &fn->loaded;
 142         }
 143         conv_total += conv;
 144         if (conv)
 145                 goto again;
 146         if (conv_total) {
 147                 /*
 148                  * Other pre_select functions might have already been called by
 149                  * now and decided to do nothing, e.g. because their output
 150                  * buffer was full or the input buffer was empty. We just
 151                  * converted something which caused these buffers to change but
 152                  * we can't make the other tasks reconsider their decision at
 153                  * this point.  So force a minimal timeout for the next select
 154                  * call to avoid unnecessary delays.
 155                  */
 156                 s->timeout.tv_sec = 0;
 157                 s->timeout.tv_usec = 1;
 158         }
 159         if (*fc->input_error >= 0)
 160                 return;
 161         if (*fc->out_loaded)
 162                 return;
 163         if (*fc->in_loaded && conv_total)
 164                 return;
 165         t->error = -E_FC_EOF;
 166 }
 167
 168 /**
 169  * Close all filter nodes and their callbacks.
 170  *
 171  * \param fc The filter chain to close.
 172  *
 173  * For each filter node determined by \a fc, call the close function of each
 174  * registered filter callback as well as the close function of the
 175  * corresponding filter.  Free all resources and destroy all callback lists and
 176  * the filter node list.
 177  *
 178  * \sa filter::close, filter_callback::close
 179  */
 180 void close_filters(struct filter_chain *fc)
 181 {
 182         struct filter_node *fn;
 183         int i;
 184
 185         if (!fc)
 186                 return;
 187         PARA_NOTICE_LOG("closing filter chain %p\n", fc);
 188         FOR_EACH_FILTER_NODE(fn, fc, i) {
 189                 struct filter *f = filters + fn->filter_num;
 190                 close_callbacks(fn);
 191                 PARA_INFO_LOG("closing %s filter\n", f->name);
 192                 f->close(fn);
 193         }
 194         free(fc->filter_nodes);
 195 }
 196
 197 /*
 198  * If the filter has a command line parser and options is not NULL, run it.
 199  * Returns filter_num on success, negative on errors
 200  */
 201 static int parse_filter_args(int filter_num, char *options, void **conf)
 202 {
 203         struct filter *f = &filters[filter_num];
 204         int ret, i, argc = 2;
 205         char **argv;
 206
 207 //      PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
 208 //              options? options : "(none)", f->parse_config);
 209         if (!f->parse_config)
 210                 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
 211 //      PARA_DEBUG_LOG("options: %s\n", options);
 212         argc = create_argv(options, " \t", &argv);
 213         if (argc < 0)
 214                 return -E_BAD_FILTER_OPTIONS;
 215         PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
 216         for (i = argc - 1; i >= 0; i--)
 217                 argv[i + 1] = argv[i];
 218         argv[0] = para_strdup(f->name);
 219         argc++;
 220         ret = f->parse_config(argc, argv, conf);
 221         free(argv[argc - 1]);
 222         argv[argc - 1] = NULL;
 223         free_argv(argv);
 224         return ret < 0? ret : filter_num;
 225 }
 226
 227 /**
 228  * Check the filter command line options.
 229  *
 230  * \param fa The command line options.
 231  * \param conf Points to the filter configuration upon successful return.
 232  *
 233  * Check if \a fa starts with a the name of a supported filter, followed by
 234  * a colon. If yes, call the command line parser of that filter.
 235  *
 236  * \return On success, the number of the filter is returned and \a conf
 237  * is initialized to point to the filter configuration determined by \a fa.
 238  * On errors, a negative value is returned.
 239  *
 240  * Note: If \a fa specifies a filter that has no command line parser success is
 241  * returned, and \a conf is initialized to \p NULL.
 242  *
 243  * \sa filter::parse_config
 244  */
 245 int check_filter_arg(char *fa, void **conf)
 246 {
 247         int j;
 248
 249         *conf = NULL;
 250 //      PARA_DEBUG_LOG("arg: %s\n", fa);
 251         FOR_EACH_SUPPORTED_FILTER(j) {
 252                 const char *name = filters[j].name;
 253                 size_t len = strlen(name);
 254                 char c;
 255                 if (strlen(fa) < len)
 256                         continue;
 257                 if (strncmp(name, fa, len))
 258                         continue;
 259                 c = fa[len];
 260                 if (c && c != ' ')
 261                         continue;
 262                 if (c && !filters[j].parse_config)
 263                         return -E_BAD_FILTER_OPTIONS;
 264                 return parse_filter_args(j, c? fa + len + 1 :
 265                         fa + strlen(fa), conf);
 266         }
 267         return -E_UNSUPPORTED_FILTER;
 268 }
 269
 270 void print_filter_helps(int detailed)
 271 {
 272         int i;
 273
 274         printf_or_die("\nAvailable filters: \n\t");
 275         FOR_EACH_SUPPORTED_FILTER(i)
 276                 printf_or_die("%s%s", i? " " : "", filters[i].name);
 277         printf_or_die("\n\n");
 278
 279         FOR_EACH_SUPPORTED_FILTER(i) {
 280                 struct filter *f = filters + i;
 281
 282                 if (!f->help.short_help)
 283                         continue;
 284                 printf_or_die("Options for %s:\n", f->name);
 285                 ggo_print_help(&f->help, detailed);
 286         }
 287
 288 }