fix two bugs concerning blocking fds
[paraslash.git] / stat.c
1 /*
2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /**
20 * \file stat.c functions used for sending/receiving the status of para_server
21 * and para_audiod
22 */
23 #include "para.h"
24 #include "close_on_fork.h"
25 #include "list.h"
26 #include "error.h"
27 #include "string.h"
28 #include "fd.h"
29
30 /** the maximal number of simultaneous connections */
31 #define MAX_STAT_CLIENTS 50
32
33 /**
34 * describes a status client of para_audiod
35 *
36 * There's one such structure per audiod client that sent the 'stat' command.
37 *
38 * A status client is identified by its file descriptor. para_audiod
39 * keeps a list of connected status clients.
40 */
41 struct stat_client {
42 /** the stat client's file descriptor */
43 int fd;
44 /** bitmask of those status items the client is interested in */
45 long unsigned item_mask;
46 /** its entry in the list of stat clients */
47 struct list_head node;
48 };
49
50 static struct list_head client_list;
51 static int initialized;
52 static int num_clients;
53
54 /**
55 * the list of all status items sent by para_server/para_audiod
56 */
57 const char *status_item_list[NUM_STAT_ITEMS] = {
58 [SI_STATUS_BAR] = "status_bar",
59 [SI_STATUS] = "status",
60 [SI_NUM_PLAYED] = "num_played",
61
62 [SI_MTIME] = "mtime",
63 [SI_LENGTH_MIN] = "length_min",
64 [SI_LENGTH_SEC] = "length_sec",
65
66 [SI_FILE_SIZE] = "file_size",
67 [SI_STATUS_FLAGS] = "status_flags",
68 [SI_FORMAT] = "format",
69
70 [SI_SCORE] = "score",
71 [SI_AUDIO_INFO1] = "audio_file_info1",
72 [SI_AUDIO_INFO2] = "audio_file_info2",
73
74 [SI_AUDIO_INFO3] = "audio_file_info3",
75 [SI_DBINFO1] = "dbinfo1",
76 [SI_DBINFO2] = "dbinfo2",
77
78 [SI_DBINFO3] = "dbinfo3",
79 [SI_DECODER_FLAGS] = "decoder_flags",
80 [SI_AUDIOD_STATUS] = "audiod_status",
81
82 [SI_PLAY_TIME] = "play_time",
83 [SI_UPTIME] = "uptime",
84 [SI_OFFSET] = "offset",
85
86 [SI_LENGTH] = "length",
87 [SI_STREAM_START] = "stream_start",
88 [SI_CURRENT_TIME] = "current_time",
89
90 [SI_AUDIOD_UPTIME] = "audiod_uptime",
91 [SI_SELECTOR] = "dbtool"
92 };
93
94 static void dump_stat_client_list(void)
95 {
96 struct stat_client *sc;
97
98 if (!initialized)
99 return;
100 list_for_each_entry(sc, &client_list, node)
101 PARA_INFO_LOG("stat client on fd %d\n", sc->fd);
102 }
103 /**
104 * add a status client to the list
105 *
106 * \return Positive value on success, or -E_TOO_MANY_CLIENTS if
107 * the number of connected clients exceeds #MAX_STAT_CLIENTS
108 */
109 int stat_client_add(int fd, long unsigned mask)
110 {
111 struct stat_client *new_client;
112
113 if (num_clients >= MAX_STAT_CLIENTS) {
114 PARA_ERROR_LOG("maximal number of stat clients (%d) exceeded\n",
115 MAX_STAT_CLIENTS);
116 return -E_TOO_MANY_CLIENTS;
117 }
118 if (!initialized) {
119 INIT_LIST_HEAD(&client_list);
120 initialized = 1;
121 }
122 PARA_INFO_LOG("adding client on fd %d\n", fd);
123 new_client = para_malloc(sizeof(struct stat_client));
124 new_client->fd = fd;
125 new_client->item_mask = mask;
126 list_add(&new_client->node, &client_list);
127 dump_stat_client_list();
128 num_clients++;
129 return 1;
130 }
131 /**
132 * write a message to all connected status clients
133 *
134 * \param msg a \p NULL terminated buffer
135 * \param itemnum The number of the status item of \a msg
136 *
137 * On write errors, remove the status client from the client list and close its
138 * file descriptor.
139 */
140 void stat_client_write(char *msg, int itemnum)
141 {
142 struct stat_client *sc, *tmp;
143 ssize_t len;
144 struct timeval tv = {0 , 0};
145
146 if (!initialized)
147 return;
148 len = strlen(msg);
149 list_for_each_entry_safe(sc, tmp, &client_list, node) {
150 int fd = sc->fd, ret;
151 fd_set wfds;
152
153 if (!((1 << itemnum) & sc->item_mask))
154 continue;
155 FD_ZERO(&wfds);
156 FD_SET(fd, &wfds);
157 // PARA_DEBUG_LOG("%s: p=%lx\n", __func__, (long)p);
158 ret = para_select(fd + 1, NULL, &wfds, &tv);
159 if (ret > 0) {
160 ret = write(fd, msg, len);
161 PARA_DEBUG_LOG("dumped %s to fd %d, ret = %d\n", msg, fd, ret);
162 if (ret == len )
163 continue;
164 }
165 /* write error or fd not ready for writing */
166 close(fd);
167 num_clients--;
168 PARA_INFO_LOG("deleting client on fd %d\n", fd);
169 list_del(&sc->node);
170 free(sc);
171 dump_stat_client_list();
172 }
173 PARA_DEBUG_LOG("%d client(s)\n", num_clients);
174 }
175
176
177 /**
178 * check if string is a known status item.
179 *
180 * \param item buffer containing the text to check
181 *
182 * \return If \a item is a valid status item, the number of that status item is
183 * returned. Otherwise, this function returns \p -E_UNKNOWN_STAT_ITEM.
184 */
185 int stat_item_valid(const char *item)
186 {
187 int i;
188 if (!item || !*item) {
189 PARA_ERROR_LOG("%s\n", "no item");
190 return -E_UNKNOWN_STAT_ITEM;
191 }
192 FOR_EACH_STAT_ITEM(i)
193 if (!strcmp(status_item_list[i], item))
194 return i;
195 return -E_UNKNOWN_STAT_ITEM;
196 }
197
198 /**
199 * check if line starts with known status item.
200 *
201 * \param line buffer containing the line
202 *
203 * \return If the beginning of \a line matches any paraslash status item and is
204 * followed by a colon, the number of that status item is returned. Otherwise,
205 * this function returns \p -E_UNKNOWN_STAT_ITEM.
206 */
207 int stat_line_valid(const char *line)
208 {
209 int i;
210 size_t line_len;
211
212 if (!line || !*line)
213 return -E_UNKNOWN_STAT_ITEM;
214 line_len = strlen(line);
215 FOR_EACH_STAT_ITEM(i) {
216 const char *s = status_item_list[i];
217 size_t item_len = strlen(s);
218
219 if (line_len > item_len && line[item_len] == ':' &&
220 !strncmp(line, s, item_len))
221 return i;
222 }
223 return -E_UNKNOWN_STAT_ITEM;
224 }
225
226 /**
227 * call a custom function for each complete line
228 *
229 * \param buf the buffer containing data seperated by newlines
230 * \param n the number of bytes in \a buf
231 * \param line_handler the custom function
232 *
233 * If \a line_handler is \p NULL, return number of complete lines in buf.
234 * Otherwise, call \a line_handler for each complete line. The rest of the
235 * buffer (last chunk containing incomplete line is moved to the beginning of
236 * the buffer.
237 *
238 * \return If line_handler is not NULL, this function returns the number
239 * of bytes not handled to \a line_handler.
240 */
241 unsigned for_each_line(char *buf, int n, void (*line_handler)(char *))
242 {
243 char *start = buf, *end;
244 int i, num_lines = 0;
245
246 // PARA_INFO_LOG("buf: %s", buf);
247 while (start < buf + n) {
248 char *next_null;
249 char *next_cr;
250
251 next_cr = memchr(start, '\n', buf + n - start);
252 next_null = memchr(start, '\0', buf + n - start);
253 if (!next_cr && !next_null)
254 break;
255 if (next_cr && next_null) {
256 end = next_cr < next_null? next_cr : next_null;
257 } else if (next_null) {
258 end = next_null;
259 } else
260 end = next_cr;
261 num_lines++;
262 if (line_handler) {
263 *end = '\0';
264 // PARA_INFO_LOG("calling line handler: %s\n", start);
265 line_handler(start);
266 start = ++end;
267 } else
268 start = ++end;
269 }
270 if (!line_handler)
271 return num_lines;
272 i = buf + n - start;
273 if (i && i != n)
274 memmove(buf, start, i);
275 return i;
276 }
277