Merge branch 'maint'
[paraslash.git] / stdout.c
1 /*
2 * Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>
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 "para.h"
10 #include "list.h"
11 #include "sched.h"
12 #include "fd.h"
13 #include "error.h"
14 #include "stdout.h"
15 #include "buffer_tree.h"
16
17 /* Add STDOUT_FILENO to the write fd set if there is input data available. */
18 static void stdout_pre_select(struct sched *s, void *context)
19 {
20 struct stdout_task *sot = context;
21 int ret;
22
23 ret = btr_node_status(sot->btrn, 0, BTR_NT_LEAF);
24 if (ret > 0)
25 para_fd_set(STDOUT_FILENO, &s->wfds, &s->max_fileno);
26 else if (ret < 0)
27 sched_min_delay(s);
28 }
29
30 /*
31 * This function writes input data from the buffer tree to stdout if
32 * STDOUT_FILENO is writable.
33 */
34 static int stdout_post_select(struct sched *s, void *context)
35 {
36 struct stdout_task *sot = context;
37 struct btr_node *btrn = sot->btrn;
38 int ret;
39 char *buf;
40 size_t sz;
41
42 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
43 if (ret < 0)
44 goto out;
45 if (ret == 0)
46 return 0;
47 if (!FD_ISSET(STDOUT_FILENO, &s->wfds))
48 return 0;
49
50 if (sot->must_set_nonblock_flag) {
51 ret = mark_fd_nonblocking(STDOUT_FILENO);
52 if (ret < 0)
53 goto out;
54 sot->must_set_nonblock_flag = false;
55 }
56 for (;;) {
57 sz = btr_next_buffer(btrn, &buf);
58 if (sz == 0)
59 break;
60 ret = xwrite(STDOUT_FILENO, buf, sz);
61 if (ret <= 0)
62 break;
63 btr_consume(btrn, ret);
64 }
65 out:
66 if (ret < 0) {
67 btr_remove_node(&sot->btrn);
68 /* Revert to blocking mode if necessary. */
69 fcntl(STDOUT_FILENO, F_SETFL, sot->fd_flags);
70 }
71 return ret;
72 }
73
74 /**
75 * Register a stdout task structure.
76 *
77 * \param sot The stdout task structure to register.
78 * \param s The task will be added to this scheduler's task list.
79 *
80 * This sets up \a sot and registers a task with \a sot as context pointer.
81 */
82 void stdout_task_register(struct stdout_task *sot, struct sched *s)
83 {
84 int ret;
85 struct task_info ti = {
86 .pre_select = stdout_pre_select,
87 .post_select = stdout_post_select,
88 .context = sot,
89 .name = "stdout",
90 };
91
92 /* See stdin.c for details. */
93 ret = fcntl(STDOUT_FILENO, F_GETFL);
94 if (ret < 0) {
95 PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno));
96 exit(EXIT_FAILURE);
97 }
98 sot->fd_flags = ret;
99 sot->must_set_nonblock_flag = (sot->fd_flags & O_NONBLOCK) == 0;
100 sot->task = task_register(&ti, s);
101 }