fix multiple simultaneous writers
[paraslash.git] / file_writer.c
1 /*
2 * Copyright (C) 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 /** \file file_writer.c simple output plugin for testing purposes */
20
21 #include "para.h"
22 #include "list.h"
23 #include "sched.h"
24 #include "write.h"
25 #include "string.h"
26 #include "fd.h"
27 #include "file_write.cmdline.h"
28 #include "error.h"
29
30 /** data specific to the file writer */
31 struct private_file_writer_data {
32 /** the file descriptor of the output file */
33 int fd;
34 /** non-zero if \a fd was added to the write fd set */
35 int check_fd;
36 };
37
38 static int file_writer_open(struct writer_node *wn)
39 {
40 struct private_file_writer_data *pfwd = para_calloc(
41 sizeof(struct private_file_writer_data));
42 struct file_write_args_info *conf = wn->conf;
43 char *filename;
44 if (conf->filename_given)
45 filename = conf->filename_arg;
46 else {
47 char *tmp = para_tmpname(), *home = para_homedir();
48 filename = make_message("%s/.paraslash/%s", home, tmp);
49 free(home);
50 free(tmp);
51 }
52 wn->private_data = pfwd;
53 pfwd->fd = open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
54 if (!conf->filename_given)
55 free(filename);
56 if (pfwd->fd >= 0)
57 return 8192;
58 free(pfwd);
59 return -E_FW_OPEN;
60 }
61
62 static int file_writer_write(char *data, size_t nbytes, struct writer_node *wn)
63 {
64 struct private_file_writer_data *pfwd = wn->private_data;
65 int ret = write(pfwd->fd, data, nbytes);
66 if (ret < 0)
67 ret = -E_FW_WRITE;
68 return ret;
69 }
70
71 static int file_writer_pre_select(struct sched *s, struct writer_node *wn)
72 {
73 struct private_file_writer_data *pfwd = wn->private_data;
74 struct writer_node_group *wng = wn->wng;
75
76 pfwd->check_fd = 0;
77 if (pfwd->fd <= 0)
78 return -E_FW_NO_FILE;
79 if (!*wng->loaded)
80 return 1;
81 para_fd_set(pfwd->fd, &s->wfds, &s->max_fileno);
82 pfwd->check_fd = 1;
83 return 1;
84 }
85
86 static int file_writer_post_select(struct sched *s, struct writer_node *wn)
87 {
88 struct private_file_writer_data *pfwd = wn->private_data;
89 struct writer_node_group *wng = wn->wng;
90 int ret;
91
92 if (!pfwd->check_fd)
93 return 1;
94 if (*wng->loaded <= wn->written)
95 return 1;
96 if (!FD_ISSET(pfwd->fd, &s->wfds))
97 return 1;
98 // PARA_INFO_LOG("writing %zd\n", *wng->loaded);
99 ret = write(pfwd->fd, wng->buf + wn->written,
100 *wng->loaded - wn->written);
101 if (ret < 0)
102 return -E_FW_WRITE;
103 wn->written += ret;
104 return 1;
105 }
106
107 static void file_writer_close(struct writer_node *wn)
108 {
109 struct private_file_writer_data *pfwd = wn->private_data;
110 close(pfwd->fd);
111 free(pfwd);
112 }
113
114 __malloc void *file_writer_parse_config(char *options)
115 {
116 PARA_INFO_LOG("options: %s\n", options);
117 struct file_write_args_info *conf
118 = para_calloc(sizeof(struct file_write_args_info));
119 int ret = file_cmdline_parser_string(options, conf, "file_write");
120 PARA_INFO_LOG("conf->filename_given: %d\n", conf->filename_given);
121 if (!ret)
122 return conf;
123 free(conf);
124 return NULL;
125 }
126
127 /** the init function of the file writer */
128 void file_writer_init(struct writer *w)
129 {
130 w->open = file_writer_open;
131 w->write = file_writer_write;
132 w->pre_select = file_writer_pre_select;
133 w->post_select = file_writer_post_select;
134 w->parse_config = file_writer_parse_config;
135 w->close = file_writer_close;
136 w->shutdown = NULL; /* nothing to do */
137 }