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 <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  * \sa filter::init
  27  */
  28 void filter_init(void)
  29 {
  30         int i;
  31
  32         FOR_EACH_SUPPORTED_FILTER(i)
  33                 filters[i].init(filters + i);
  34 }
  35
  36 /**
  37  * Close and destroy a filter callback.
  38  *
  39  * \param fcb The filter callback to close.
  40  *
  41  * This removes \a fcb from the list of filter callbacks and calls
  42  * the close callback associated with \a fcb.
  43  */
  44 static void close_filter_callback(struct filter_callback *fcb)
  45 {
  46         PARA_NOTICE_LOG("closing filter_callback %p, data: %p\n", fcb, fcb->data);
  47         list_del(&fcb->node);
  48         fcb->close(fcb);
  49 }
  50
  51 /**
  52  * Close all callbacks of a filter node.
  53  *
  54  * \param fn The filter node which contains the filter callbacks to be closed.
  55  *
  56  * Call close_filter_callback() for each entry in the filter callback list
  57  * of \a fn.
  58  */
  59 static void close_callbacks(struct filter_node *fn)
  60 {
  61         struct filter_callback *fcb, *tmp;
  62
  63         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  64                 PARA_INFO_LOG("closing %s filter callback\n",
  65                         filters[fn->filter_num].name);
  66                 close_filter_callback(fcb);
  67         }
  68 }
  69
  70 static void call_callbacks(struct filter_node *fn, char *inbuf, size_t inlen,
  71         char *outbuf, size_t outlen)
  72 {
  73         struct filter_callback *fcb, *tmp;
  74         list_for_each_entry_safe(fcb, tmp, &fn->callbacks, node) {
  75                 int ret;
  76                 if (inlen && fcb->input_cb) {
  77                         ret = fcb->input_cb(inbuf, inlen, fcb);
  78                         if (ret < 0) {
  79                                 close_filter_callback(fcb);
  80                                 continue;
  81                         }
  82                 }
  83                 if (!outlen || !fcb->output_cb)
  84                         continue;
  85                 ret = fcb->output_cb(outbuf, outlen, fcb);
  86                 if (ret < 0)
  87                         close_filter_callback(fcb);
  88         }
  89 }
  90
  91 /**
  92  * Call the convert function of each filter.
  93  *
  94  * \param s Unused.
  95  * \param t The task identifying the filter chain.
  96  *
  97  * This is the core function of the filter subsystem. It loops over the list of
  98  * filter nodes determined by \a t and calls the filter's convert function if
  99  * there is input available for the filter node in question. If the convert
 100  * function consumed some or all of its input data, all registered input
 101  * callbacks are called.  Similarly, if a convert function produced output, all
 102  * registered output callbacks get called.
 103  *
 104  * On errors a (negative) error code is stored in t->error.
 105  *
 106  * \sa filter_node, filter#convert, filter_callback.
 107  */
 108 void filter_post_select(__a_unused struct sched *s, struct task *t)
 109 {
 110         struct filter_chain *fc = container_of(t, struct filter_chain, task);
 111         struct filter_node *fn;
 112         char *ib;
 113         size_t *loaded;
 114         int i, conv, conv_total = 0;
 115
 116         if (fc->output_error && *fc->output_error < 0) {
 117                 t->error =  *fc->output_error;
 118                 return;
 119         }
 120 again:
 121         ib = *fc->inbufp;
 122         loaded = fc->in_loaded;
 123         conv = 0;
 124         FOR_EACH_FILTER_NODE(fn, fc, i) {
 125                 struct filter *f = filters + fn->filter_num;
 126                 if (fn->loaded < fn->bufsize) {
 127                         size_t size, old_fn_loaded = fn->loaded;
 128                         t->error = f->convert(ib, *loaded, fn);
 129                         if (t->error < 0)
 130                                 return;
 131                         size = t->error;
 132                         call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
 133                                 fn->loaded - old_fn_loaded);
 134                         *loaded -= size;
 135                         conv += size + fn->loaded - old_fn_loaded;
 136                         if (*loaded && size)
 137                                 memmove(ib, ib + size, *loaded);
 138                 }
 139                 ib = fn->buf;
 140                 loaded = &fn->loaded;
 141         }
 142         conv_total += conv;
 143         if (conv)
 144                 goto again;
 145         if (*fc->input_error >= 0)
 146                 return;
 147         if (*fc->out_loaded)
 148                 return;
 149         if (*fc->in_loaded && conv_total)
 150                 return;
 151         t->error = -E_FC_EOF;
 152 }
 153
 154 /**
 155  * Close all filter nodes and their callbacks.
 156  *
 157  * \param fc The filter chain to close.
 158  *
 159  * For each filter node determined by \a fc, call the close function of each
 160  * registered filter callback as well as the close function of the
 161  * corresponding filter.  Free all resources and destroy all callback lists and
 162  * the filter node list.
 163  *
 164  * \sa filter::close, filter_callback::close
 165  */
 166 void close_filters(struct filter_chain *fc)
 167 {
 168         struct filter_node *fn;
 169         int i;
 170
 171         if (!fc)
 172                 return;
 173         PARA_NOTICE_LOG("closing filter chain %p\n", fc);
 174         FOR_EACH_FILTER_NODE(fn, fc, i) {
 175                 struct filter *f = filters + fn->filter_num;
 176                 close_callbacks(fn);
 177                 PARA_INFO_LOG("closing %s filter\n", f->name);
 178                 f->close(fn);
 179         }
 180         free(fc->filter_nodes);
 181 }
 182
 183 /*
 184  * If the filter has a command line parser and options is not NULL, run it.
 185  * Returns filter_num on success, negative on errors
 186  */
 187 static int parse_filter_args(int filter_num, char *options, void **conf)
 188 {
 189         struct filter *f = &filters[filter_num];
 190         int ret, i, argc = 2;
 191         char **argv;
 192
 193 //      PARA_DEBUG_LOG("%s, options: %s, parser: %p\n", f->name,
 194 //              options? options : "(none)", f->parse_config);
 195         if (!f->parse_config)
 196                 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
 197 //      PARA_DEBUG_LOG("options: %s\n", options);
 198         argc = split_args(options, &argv, " \t");
 199 //              PARA_DEBUG_LOG("argc = %d, argv[0]: %s\n", argc, argv[0]);
 200         for (i = argc - 1; i >= 0; i--)
 201                 argv[i + 1] = argv[i];
 202         argv[0] = para_strdup(f->name);
 203         argc += 1;
 204         ret = f->parse_config(argc, argv, conf);
 205         free(argv[0]);
 206         free(argv);
 207         return ret < 0? ret : filter_num;
 208 }
 209
 210 /**
 211  * Check the filter command line options.
 212  *
 213  * \param fa The command line options.
 214  * \param conf Points to the filter configuration upon successful return.
 215  *
 216  * Check if \a fa starts with a the name of a supported filter, followed by
 217  * a colon. If yes, call the command line parser of that filter.
 218  *
 219  * \return On success, the number of the filter is returned and \a conf
 220  * is initialized to point to the filter configuration determined by \a fa.
 221  * On errors, a negative value is returned.
 222  *
 223  * Note: If \a fa specifies a filter that has no command line parser success is
 224  * returned, and \a conf is initialized to \p NULL.
 225  *
 226  * \sa filter::parse_config
 227  */
 228 int check_filter_arg(char *fa, void **conf)
 229 {
 230         int j;
 231
 232         *conf = NULL;
 233 //      PARA_DEBUG_LOG("arg: %s\n", fa);
 234         FOR_EACH_SUPPORTED_FILTER(j) {
 235                 const char *name = filters[j].name;
 236                 size_t len = strlen(name);
 237                 char c;
 238                 if (strlen(fa) < len)
 239                         continue;
 240                 if (strncmp(name, fa, len))
 241                         continue;
 242                 c = fa[len];
 243                 if (c && c != ' ')
 244                         continue;
 245                 if (c && !filters[j].parse_config)
 246                         return -E_BAD_FILTER_OPTIONS;
 247                 return parse_filter_args(j, c? fa + len + 1 :
 248                         fa + strlen(fa), conf);
 249         }
 250         return -E_UNSUPPORTED_FILTER;
 251 }
 252
 253 void print_filter_helps(int detailed)
 254 {
 255         int i;
 256
 257         printf_or_die("\nAvailable filters: \n\t");
 258         FOR_EACH_SUPPORTED_FILTER(i)
 259                 printf_or_die("%s%s", i? " " : "", filters[i].name);
 260         printf_or_die("\n\n");
 261
 262         FOR_EACH_SUPPORTED_FILTER(i) {
 263                 struct filter *f = filters + i;
 264
 265                 if (!f->help.short_help)
 266                         continue;
 267                 printf_or_die("Options for %s:\n", f->name);
 268                 ggo_print_help(&f->help, detailed);
 269         }
 270
 271 }