server: Deplete user list on exit.
[paraslash.git] / 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 }