btr: Make it kind of work for http recv + stdout.
[paraslash.git] / stdout.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 stdout.c Functions that deal with writing to stdout. */
8
9 #include <dirent.h> /* readdir() */
10 #include <assert.h>
11 #include <stdbool.h>
12
13 #include "para.h"
14 #include "list.h"
15 #include "sched.h"
16 #include "fd.h"
17 #include "error.h"
18 #include "stdout.h"
19 #include "buffer_tree.h"
20
21 /**
22 * The pre_select function of the stdout task.
23 *
24 * \param s The scheduler this task was registered to.
25 * \param t The task structure of the stdout task.
26 *
27 * This function is always successful. If there is data available in the input
28 * buffer, it adds \p STDOUT_FILENO to the write fd set of \a s.
29 */
30 static void stdout_pre_select(struct sched *s, struct task *t)
31 {
32 struct stdout_task *sot = container_of(t, struct stdout_task, task);
33
34 t->error = 0;
35 sot->check_fd = 0;
36 if (!*sot->loaded) {
37 if (*sot->input_error < 0) {
38 t->error = *sot->input_error;
39 s->timeout.tv_sec = 0;
40 s->timeout.tv_usec = 1;
41 }
42 return;
43 }
44 sot->check_fd = 1;
45 para_fd_set(STDOUT_FILENO, &s->wfds, &s->max_fileno);
46 }
47
48 static void stdout_pre_select_btr(struct sched *s, struct task *t)
49 {
50 struct stdout_task *sot = container_of(t, struct stdout_task, task);
51 size_t sz = btr_get_input_queue_size(sot->btrn);
52
53 t->error = 0;
54 sot->check_fd = 0;
55 if (sz == 0) {
56 if (btr_no_parent(sot->btrn)) {
57 t->error = -E_ORPHAN;
58 btr_del_node(sot->btrn);
59 s->timeout.tv_sec = 0;
60 s->timeout.tv_usec = 1;
61 }
62 return;
63 }
64 sot->check_fd = 1;
65 para_fd_set(STDOUT_FILENO, &s->wfds, &s->max_fileno);
66 }
67
68 /**
69 * The post select function of the stdout task.
70 *
71 * \param s The scheduler this task was registered to.
72 * \param t The task structure of the stdout task.
73 *
74 * This function checks if \p STDOUT_FILENO was included by in the write fd set
75 * of \a s during the previous pre_select call. If yes, and \p STDOUT_FILENO
76 * appeears to be writable, the data loaded in the input buffer is written to
77 * stdout.
78 */
79 static void stdout_post_select(struct sched *s, struct task *t)
80 {
81 struct stdout_task *sot = container_of(t, struct stdout_task, task);
82 ssize_t ret;
83
84 t->error = 0;
85 if (!sot->check_fd) {
86 if (!*sot->loaded && *sot->input_error < 0)
87 t->error = *sot->input_error;
88 return;
89 }
90 if (!FD_ISSET(STDOUT_FILENO, &s->wfds))
91 return;
92 ret = write(STDOUT_FILENO, *sot->bufp, *sot->loaded);
93 if (ret < 0) {
94 t->error = -ERRNO_TO_PARA_ERROR(errno);
95 return;
96 }
97 *sot->loaded -= ret;
98 if (*sot->loaded)
99 memmove(*sot->bufp, *sot->bufp + ret, *sot->loaded);
100 }
101
102 static void stdout_post_select_btr(struct sched *s, struct task *t)
103 {
104 struct stdout_task *sot = container_of(t, struct stdout_task, task);
105 ssize_t ret;
106 size_t sz = btr_get_input_queue_size(sot->btrn);
107 bool orphan = btr_no_parent(sot->btrn);
108 char *buf;
109
110 t->error = 0;
111 if (!sot->check_fd) {
112 if (sz == 0 && orphan) {
113 t->error = -E_ORPHAN;
114 goto err;
115 }
116 return;
117 }
118 if (!FD_ISSET(STDOUT_FILENO, &s->wfds))
119 return;
120 sz = btr_next_buffer(sot->btrn, &buf);
121 if (sz == 0)
122 return;
123 ret = write(STDOUT_FILENO, buf, sz);
124 if (ret < 0) {
125 t->error = -ERRNO_TO_PARA_ERROR(errno);
126 goto err;
127 }
128 btr_consume(sot->btrn, ret);
129 return;
130 err:
131 btr_del_node(sot->btrn);
132 }
133 /**
134 * Initialize a stdout task structure with default values.
135 *
136 * \param sot The stdout task structure.
137 *
138 * This fills in the pre/post select function poinzters of the task structure
139 * given by \a sot.
140 */
141 void stdout_set_defaults(struct stdout_task *sot)
142 {
143 int ret;
144
145 if (sot->btrn) {
146 sot->task.pre_select = stdout_pre_select_btr;
147 sot->task.post_select = stdout_post_select_btr;
148 } else {
149 sot->task.pre_select = stdout_pre_select;
150 sot->task.post_select = stdout_post_select;
151 }
152 sprintf(sot->task.status, "stdout writer");
153 ret = mark_fd_nonblocking(STDOUT_FILENO);
154 if (ret >= 0)
155 return;
156 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
157 exit(EXIT_FAILURE);
158 }