Fix com_pause().
[paraslash.git] / stdout.c
1 /*
2 * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file stdout.c functions that deal with writing to stdout */
8
9 #include <dirent.h> /* readdir() */
10 #include <assert.h>
11
12 #include "para.h"
13 #include "string.h"
14 #include "list.h"
15 #include "sched.h"
16 #include "fd.h"
17 #include "error.h"
18 #include "stdout.h"
19
20 /**
21 * the pre_select function of the stdout task
22 *
23 * \param s the scheduler this task was registered to
24 * \param t the task structure of the stdout task
25 *
26 * This function is always successful. If there is data available in the input
27 * buffer, it adds \p STDOUT_FILENO to the write fd set of \a s.
28 */
29 static void stdout_pre_select(struct sched *s, struct task *t)
30 {
31 struct stdout_task *sot = t->private_data;
32
33 t->ret = 1;
34 sot->check_fd = 0;
35 if (!*sot->loaded) {
36 if (*sot->input_eof) {
37 t->ret = -E_STDOUT_EOF;
38 s->timeout.tv_sec = 0;
39 s->timeout.tv_usec = 1;
40 }
41 return;
42 }
43 sot->check_fd = 1;
44 para_fd_set(STDOUT_FILENO, &s->wfds, &s->max_fileno);
45 }
46
47 /**
48 * the post select function of the stdout task
49 *
50 * \param s the scheduler this task was registered to
51 * \param t the task structure of the stdout task
52 *
53 * This function checks if \p STDOUT_FILENO was included by in the write fd set
54 * of \a s during the previous pre_select call. If yes, and \p STDOUT_FILENO
55 * appeears to be writable, the data loaded in the input buffer is written to
56 * stdout.
57 */
58 static void stdout_post_select(struct sched *s, struct task *t)
59 {
60 struct stdout_task *sot = t->private_data;
61 ssize_t ret;
62
63 t->ret = 1;
64 if (!sot->check_fd) {
65 if (*sot->input_eof)
66 t->ret = -E_STDOUT_EOF;
67 return;
68 }
69 if (!FD_ISSET(STDOUT_FILENO, &s->wfds))
70 return;
71 t->ret = -E_STDOUT_WRITE;
72 ret = write(STDOUT_FILENO, sot->buf, *sot->loaded);
73 if (ret <= 0)
74 return;
75 *sot->loaded -= ret;
76 if (*sot->loaded)
77 memmove(sot->buf, sot->buf + ret, *sot->loaded);
78 t->ret = 1;
79 }
80
81 static void stdout_default_event_handler(struct task *t)
82 {
83 PARA_NOTICE_LOG("%p: %s\n", t, PARA_STRERROR(-t->ret));
84 unregister_task(t);
85 }
86
87 /**
88 * initialize a stdout task structure with default values
89 *
90 * \param sot the stdout task structure
91 *
92 * This fills in the pre/post select function poinzters of the task structure
93 * given by \a sot. It also sets up a default error handler which unregisters
94 * the task on errors and clears the eof flag of \a sot.
95 */
96 void stdout_set_defaults(struct stdout_task *sot)
97 {
98 sot->task.private_data = sot;
99 sot->task.pre_select = stdout_pre_select;
100 sot->task.post_select = stdout_post_select;
101 sot->task.event_handler = stdout_default_event_handler;
102 sot->eof = 0;
103 mark_fd_nonblock(STDOUT_FILENO);
104 sprintf(sot->task.status, "stdout writer");
105 }