Merge branch 'master' into next
[paraslash.git] / grab_client.c
1 /*
2 * Copyright (C) 2006-2009 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 #include <dirent.h>
12 #include <stdbool.h>
13
14 #include "para.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "ggo.h"
18 #include "buffer_tree.h"
19 #include "filter.h"
20 #include "grab_client.h"
21 #include "audiod.h"
22 #include "error.h"
23 #include "string.h"
24 #include "fd.h"
25
26 /**
27 * How to handle blocking writes for the grab client fds.
28 */
29 enum grab_mode {
30 /** Ignore the data and do not write. */
31 GM_SLOPPY,
32 /** Write anyway (default). */
33 GM_AGGRESSIVE,
34 /** Close fd if write would block. */
35 GM_PEDANTIC,
36 };
37
38 /** Flags specified as arguments to the grab command. */
39 enum grab_flags {
40 /** Stop grabbing if audio file changes. */
41 GF_ONE_SHOT = 1,
42 };
43
44 /** Describes one active grab client. */
45 struct grab_client {
46 /* The value of the -p option. */
47 char *parent;
48 /* The value of the -n option. */
49 char *name;
50 /** The file descriptor to send the grabbed stream to. */
51 int fd;
52 /** See \ref grab_mode. */
53 enum grab_mode mode;
54 /** Flags given at the command line. */
55 enum grab_flags flags;
56 /** The point of the grab client's node in the buffer tree. */
57 struct btr_node *btrn;
58 /* The task of this grab client. */
59 struct task task;
60 /** Belongs to either the active or the inactive list. */
61 struct list_head node;
62 };
63
64 /* Grab clients that are attached to a btr node. */
65 INITIALIZED_LIST_HEAD(active_grab_client_list);
66 /* Grab clients that are not currently attached any btr node. */
67 INITIALIZED_LIST_HEAD(inactive_grab_client_list);
68
69 static int gc_write(struct grab_client *gc, char *buf, size_t len)
70 {
71 int ret = write_ok(gc->fd);
72
73 if (ret < 0)
74 goto err;
75 if (ret == 0) { /* fd not ready */
76 if (gc->mode == GM_PEDANTIC)
77 goto err;
78 if (gc->mode == GM_SLOPPY)
79 return len;
80 }
81 ret = write_nonblock(gc->fd, buf, len, 0);
82 if (ret < 0)
83 goto err;
84 if (ret > 0)
85 return ret;
86 if (ret == 0) {
87 if (gc->mode == GM_PEDANTIC)
88 goto err;
89 if (gc->mode == GM_SLOPPY)
90 return len;
91 }
92 return 0;
93 err:
94 return -E_GC_WRITE;
95 }
96
97 static void gc_pre_select(struct sched *s, struct task *t)
98 {
99 struct grab_client *gc = container_of(t, struct grab_client, task);
100 int ret = btr_node_status(gc->btrn, 0, BTR_NT_LEAF);
101
102 if (ret == 0)
103 return;
104 if (ret < 0) {
105 s->timeout.tv_sec = 0;
106 s->timeout.tv_usec = 0;
107 return;
108 }
109 para_fd_set(gc->fd, &s->wfds, &s->max_fileno);
110 }
111
112 /*
113 * We need this forward declaration as post_select() needs
114 * activate_grab_client and vice versa.
115 */
116 static void gc_post_select(struct sched *s, struct task *t);
117
118 /**
119 * Move a grab client to the active list and start it.
120 *
121 * \param gc The grab client to activate.
122 */
123 static void gc_activate(struct grab_client *gc)
124 {
125 struct btr_node *root = audiod_get_btr_root(), *parent;
126 char *name = gc->name? gc->name : "grab";
127
128 if (!root)
129 return;
130 parent = btr_search_node(gc->parent, root);
131 if (!parent)
132 return;
133 PARA_INFO_LOG("activating fd %d\n", gc->fd);
134 list_move(&gc->node, &active_grab_client_list);
135 gc->btrn = btr_new_node(&(struct btr_node_description)
136 EMBRACE(.name = name, .parent = parent));
137 if (!gc->task.pre_select) {
138 gc->task.pre_select = gc_pre_select;
139 gc->task.post_select = gc_post_select;
140 snprintf(gc->task.status, sizeof(gc->task.status) - 1, "%s", name);
141 gc->task.status[sizeof(gc->task.status) - 1] = '\0';
142 register_task(&gc->task);
143 }
144 }
145
146 /**
147 * Activate inactive grab clients if possible.
148 *
149 * This is called from audiod.c when the current audio file changes. It loops
150 * over all inactive grab clients and checks each grab client's configuration
151 * to determine if the client in question wishes to grab the new stream. If
152 * yes, this grab client is moved from the inactive to the active grab client list.
153 *
154 * This function also garbage collects all grab clients whose tasks have been
155 * unscheduled.
156 */
157 void activate_grab_clients(void)
158 {
159 struct grab_client *gc, *tmp;
160
161 list_for_each_entry_safe(gc, tmp, &inactive_grab_client_list, node) {
162 if (gc->task.error == -E_TASK_UNREGISTERED) {
163 list_del(&gc->node);
164 free(gc);
165 continue;
166 }
167 gc_activate(gc);
168 }
169 }
170
171 static int gc_close(struct grab_client *gc, int err)
172 {
173 btr_remove_node(gc->btrn);
174 btr_free_node(gc->btrn);
175 gc->btrn = NULL;
176 PARA_INFO_LOG("closing gc: %s\n", para_strerror(-err));
177 list_move(&gc->node, &inactive_grab_client_list);
178 if (err == -E_GC_WRITE || (gc->flags & GF_ONE_SHOT)) {
179 /*
180 * We must not free the gc structure here as it contains ->task
181 * which is still used because this function is called from
182 * post_select().
183 */
184 close(gc->fd);
185 free(gc->parent);
186 free(gc->name);
187 return 1;
188 }
189 gc_activate(gc);
190 return 0;
191 }
192
193 static void gc_post_select(__a_unused struct sched *s, struct task *t)
194 {
195 struct grab_client *gc = container_of(t, struct grab_client, task);
196 struct btr_node *btrn = gc->btrn;
197 int ret;
198 size_t sz;
199 char *buf;
200
201 t->error = 0;
202 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
203 if (ret == 0)
204 return;
205 if (ret < 0)
206 goto err;
207 sz = btr_next_buffer(btrn, &buf);
208 assert(sz != 0);
209 ret = gc_write(gc, buf, sz);
210 if (ret < 0)
211 goto err;
212 if (ret > 0)
213 btr_consume(btrn, ret);
214 return;
215 err:
216 t->error = gc_close(gc, ret)? ret : 0;
217 }
218
219 static int gc_check_args(int argc, char **argv, struct grab_client *gc)
220 {
221 int i;
222
223 for (i = 1; i < argc; i++) {
224 const char *arg = argv[i];
225 if (arg[0] != '-')
226 break;
227 if (!strcmp(arg, "--")) {
228 i++;
229 break;
230 }
231 if (!strncmp(arg, "-m", 2)) {
232 if (*(arg + 3))
233 return -E_GC_SYNTAX;
234 switch(*(arg + 2)) {
235 case 's':
236 gc->mode = GM_SLOPPY;
237 continue;
238 case 'a':
239 gc->mode = GM_AGGRESSIVE;
240 continue;
241 case 'p':
242 gc->mode = GM_PEDANTIC;
243 continue;
244 default:
245 return -E_GC_SYNTAX;
246 }
247 }
248 if (!strcmp(arg, "-o")) {
249 gc->flags |= GF_ONE_SHOT;
250 continue;
251 }
252 if (!strncmp(arg, "-p=", 3)) {
253 gc->parent = para_strdup(arg + 3);
254 continue;
255 }
256 if (!strncmp(arg, "-n=", 3)) {
257 gc->name = para_strdup(arg + 3);
258 continue;
259 }
260 return -E_GC_SYNTAX;
261 }
262 if (i != argc)
263 return -E_GC_SYNTAX;
264 return 1;
265 }
266
267 /**
268 * Check the command line options and allocate a grab_client structure.
269 *
270 * \param fd The file descriptor of the client.
271 * \param argc Argument count.
272 * \param argv Argument vector.
273 *
274 * If the command line options given by \a argc and \a argv are valid.
275 * allocate a struct grab_client and initialize it with this valid
276 * configuration.
277 *
278 * If the new grab client can be added to an existing buffer tree, activate it.
279 * Otherwise, add it to the inactive list for later activation.
280 *
281 * \return Standard.
282 */
283 int grab_client_new(int fd, int argc, char **argv)
284 {
285 int ret;
286 struct grab_client *gc = para_calloc(sizeof(struct grab_client));
287
288 ret = gc_check_args(argc, argv, gc);
289 if (ret < 0)
290 goto err_out;
291 gc->fd = fd;
292 para_list_add(&gc->node, &inactive_grab_client_list);
293 gc_activate(gc);
294 return 1;
295 err_out:
296 free(gc);
297 return ret;
298 }