grab_client.c

   1 /*
   2  * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file grab_client.c Functions for grabbing the audio stream. */
   8
   9 #include <regex.h>
  10 #include <sys/types.h>
  11
  12 #include "para.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "ggo.h"
  16 #include "buffer_tree.h"
  17 #include "filter.h"
  18 #include "grab_client.h"
  19 #include "audiod.h"
  20 #include "error.h"
  21 #include "string.h"
  22 #include "fd.h"
  23
  24 /**
  25  * How to handle blocking writes for the grab client fds.
  26  */
  27 enum grab_mode {
  28         /** Ignore the data and do not write. */
  29         GM_SLOPPY,
  30         /** Write anyway (default). */
  31         GM_AGGRESSIVE,
  32         /** Close fd if write would block. */
  33         GM_PEDANTIC,
  34 };
  35
  36 /** Flags specified as arguments to the grab command. */
  37 enum grab_flags {
  38         /** Stop grabbing if audio file changes. */
  39         GF_ONE_SHOT = 1,
  40 };
  41
  42 /** Describes one active grab client. */
  43 struct grab_client {
  44         /* The value of the -p option. */
  45         char *parent;
  46         /* The value of the -n option. */
  47         char *name;
  48         /** The file descriptor to send the grabbed stream to. */
  49         int fd;
  50         /** See \ref grab_mode. */
  51         enum grab_mode mode;
  52         /** Flags given at the command line. */
  53         enum grab_flags flags;
  54         /** The point of the grab client's node in the buffer tree. */
  55         struct btr_node *btrn;
  56         /* The task of this grab client. */
  57         struct task task;
  58         /** Belongs to either the active or the inactive list. */
  59         struct list_head node;
  60 };
  61
  62 /* Grab clients that are attached to a btr node. */
  63 static INITIALIZED_LIST_HEAD(active_grab_client_list);
  64 /* Grab clients that are not currently attached any btr node. */
  65 static INITIALIZED_LIST_HEAD(inactive_grab_client_list);
  66
  67 static int gc_write(struct grab_client *gc, char *buf, size_t len)
  68 {
  69         int ret = write_ok(gc->fd);
  70
  71         if (ret < 0)
  72                 goto err;
  73         if (ret == 0) { /* fd not ready */
  74                 if (gc->mode == GM_PEDANTIC)
  75                         goto err;
  76                 if (gc->mode == GM_SLOPPY)
  77                         return len;
  78         }
  79         ret = write_nonblock(gc->fd, buf, len);
  80         if (ret < 0)
  81                 goto err;
  82         if (ret > 0)
  83                 return ret;
  84         if (ret == 0) {
  85                 if (gc->mode == GM_PEDANTIC)
  86                         goto err;
  87                 if (gc->mode == GM_SLOPPY)
  88                         return len;
  89         }
  90         return 0;
  91 err:
  92         return -E_GC_WRITE;
  93 }
  94
  95 static void gc_pre_select(struct sched *s, struct task *t)
  96 {
  97         struct grab_client *gc = container_of(t, struct grab_client, task);
  98         int ret = btr_node_status(gc->btrn, 0, BTR_NT_LEAF);
  99
 100         if (ret == 0)
 101                 return;
 102         if (ret < 0)
 103                 sched_min_delay(s);
 104         para_fd_set(gc->fd, &s->wfds, &s->max_fileno);
 105 }
 106
 107 /*
 108  * We need this forward declaration as post_select() needs
 109  * activate_grab_client and vice versa.
 110  */
 111 static void gc_post_select(struct sched *s, struct task *t);
 112
 113 /**
 114  * Move a grab client to the active list and start it.
 115  *
 116  * \param gc The grab client to activate.
 117  */
 118 static void gc_activate(struct grab_client *gc, struct sched *s)
 119 {
 120         struct btr_node *root = audiod_get_btr_root(), *parent;
 121         char *name = gc->name? gc->name : "grab";
 122
 123         if (!root)
 124                 return;
 125         parent = btr_search_node(gc->parent, root);
 126         if (!parent)
 127                 return;
 128         PARA_INFO_LOG("activating fd %d\n", gc->fd);
 129         list_move(&gc->node, &active_grab_client_list);
 130         gc->btrn = btr_new_node(&(struct btr_node_description)
 131                 EMBRACE(.name = name, .parent = parent));
 132         gc->task.pre_select = gc_pre_select;
 133         gc->task.post_select = gc_post_select;
 134         snprintf(gc->task.status, sizeof(gc->task.status) - 1, "%s", name);
 135         gc->task.status[sizeof(gc->task.status) - 1] = '\0';
 136         gc->task.error = 0;
 137         register_task(s, &gc->task);
 138 }
 139
 140 /**
 141  * Activate inactive grab clients if possible.
 142  *
 143  * \param s Needed to schedule the grab client task.
 144  *
 145  * This is called from audiod.c when the current audio file changes. It loops
 146  * over all inactive grab clients and checks each grab client's configuration
 147  * to determine if the client in question wishes to grab the new stream.  If
 148  * yes, this grab client is moved from the inactive to the active grab client list.
 149  *
 150  * This function also garbage collects all grab clients whose tasks have been
 151  * unscheduled.
 152  */
 153 void activate_grab_clients(struct sched *s)
 154 {
 155         struct grab_client *gc, *tmp;
 156
 157         list_for_each_entry_safe(gc, tmp, &inactive_grab_client_list, node) {
 158                 if (gc->fd < 0) {
 159                         list_del(&gc->node);
 160                         free(gc);
 161                         continue;
 162                 }
 163                 gc_activate(gc, s);
 164         }
 165 }
 166
 167 static int gc_close(struct grab_client *gc, int err)
 168 {
 169         btr_remove_node(gc->btrn);
 170         btr_free_node(gc->btrn);
 171         gc->btrn = NULL;
 172         PARA_INFO_LOG("closing gc: %s\n", para_strerror(-err));
 173         list_move(&gc->node, &inactive_grab_client_list);
 174         if (err == -E_GC_WRITE || (gc->flags & GF_ONE_SHOT)) {
 175                 /*
 176                  * We must not free the gc structure here as it contains ->task
 177                  * which is still used because this function is called from
 178                  * post_select().
 179                  */
 180                 close(gc->fd);
 181                 gc->fd = -1;
 182                 free(gc->parent);
 183                 free(gc->name);
 184                 return 1;
 185         }
 186         return 0;
 187 }
 188
 189 static void gc_post_select(__a_unused struct sched *s, struct task *t)
 190 {
 191         struct grab_client *gc = container_of(t, struct grab_client, task);
 192         struct btr_node *btrn = gc->btrn;
 193         int ret;
 194         size_t sz;
 195         char *buf;
 196
 197         t->error = 0;
 198         ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
 199         if (ret == 0)
 200                 return;
 201         if (ret < 0)
 202                 goto err;
 203         sz = btr_next_buffer(btrn, &buf);
 204         assert(sz != 0);
 205         ret = gc_write(gc, buf, sz);
 206         if (ret < 0)
 207                 goto err;
 208         if (ret > 0)
 209                 btr_consume(btrn, ret);
 210         return;
 211 err:
 212         gc_close(gc, ret);
 213         t->error = ret;
 214 }
 215
 216 static int gc_check_args(int argc, char **argv, struct grab_client *gc)
 217 {
 218         int i;
 219
 220         for (i = 1; i < argc; i++) {
 221                 const char *arg = argv[i];
 222                 if (arg[0] != '-')
 223                         break;
 224                 if (!strcmp(arg, "--")) {
 225                         i++;
 226                         break;
 227                 }
 228                 if (!strncmp(arg, "-m", 2)) {
 229                         if (*(arg + 3))
 230                                 return -E_GC_SYNTAX;
 231                         switch(*(arg + 2)) {
 232                         case 's':
 233                                 gc->mode = GM_SLOPPY;
 234                                 continue;
 235                         case 'a':
 236                                 gc->mode = GM_AGGRESSIVE;
 237                                 continue;
 238                         case 'p':
 239                                 gc->mode = GM_PEDANTIC;
 240                                 continue;
 241                         default:
 242                                 return -E_GC_SYNTAX;
 243                         }
 244                 }
 245                 if (!strcmp(arg, "-o")) {
 246                         gc->flags |= GF_ONE_SHOT;
 247                         continue;
 248                 }
 249                 if (!strncmp(arg, "-p=", 3)) {
 250                         gc->parent = para_strdup(arg + 3);
 251                         continue;
 252                 }
 253                 if (!strncmp(arg, "-n=", 3)) {
 254                         gc->name = para_strdup(arg + 3);
 255                         continue;
 256                 }
 257                 return -E_GC_SYNTAX;
 258         }
 259         if (i != argc)
 260                 return -E_GC_SYNTAX;
 261         return 1;
 262 }
 263
 264 /**
 265  * Check the command line options and allocate a grab_client structure.
 266  *
 267  * \param fd The file descriptor of the client.
 268  * \param argc Argument count.
 269  * \param argv Argument vector.
 270  * \param s The scheduler to register the grab client task to.
 271  *
 272  * If the command line options given by \a argc and \a argv are valid.
 273  * allocate a struct grab_client and initialize it with this valid
 274  * configuration.
 275  *
 276  * If the new grab client can be added to an existing buffer tree, activate it.
 277  * Otherwise, add it to the inactive list for later activation.
 278  *
 279  * \return Standard.
 280  */
 281 int grab_client_new(int fd, int argc, char **argv, struct sched *s)
 282 {
 283         int ret;
 284         struct grab_client *gc = para_calloc(sizeof(struct grab_client));
 285
 286         ret = gc_check_args(argc, argv, gc);
 287         if (ret < 0)
 288                 goto err_out;
 289         gc->fd = fd;
 290         para_list_add(&gc->node, &inactive_grab_client_list);
 291         gc_activate(gc, s);
 292         return 1;
 293 err_out:
 294         free(gc);
 295         return ret;
 296 }