grab_client.c

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