2 * Copyright (C) 2006-2014 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file stdin.c Functions that deal with reading from stdin. */
18 #include "buffer_tree.h"
22 * The pre_select function of the stdin task.
24 * \param s The scheduler this task was registered to.
25 * \param t The task structure of the stdin task.
27 * This function is always successful. If there is space left in the
28 * buffer of the stdin task, it adds \p STDIN_FILENO to the read fd set
31 static void stdin_pre_select(struct sched *s, struct task *t)
33 struct stdin_task *sit = task_context(t);
36 ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
41 if (btr_pool_unused(sit->btrp) > 0)
42 return para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
43 sched_request_timeout_ms(100, s);
47 * The post select function of the stdin task.
49 * \param s The scheduler this task was registered to.
50 * \param t The task structure of the stdin task.
52 * This function checks if \p STDIN_FILENO was included by in the read fd set
53 * of \a s during the previous pre_select call. If yes, and \p STDIN_FILENO
54 * appears to be readable, data is read from stdin and fed into the buffer
57 static int stdin_post_select(struct sched *s, struct task *t)
59 struct stdin_task *sit = task_context(t);
64 ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
69 sz = btr_pool_get_buffer(sit->btrp, &buf);
72 if (sit->must_set_nonblock_flag) {
73 ret = mark_fd_nonblocking(STDIN_FILENO);
76 sit->must_set_nonblock_flag = false;
79 * Do not use the maximal size to avoid having only a single buffer
80 * reference for the whole pool. This is bad because if that single
81 * reference can not be freed, we're stuck.
83 sz = PARA_MIN(sz, btr_pool_size(sit->btrp) / 2);
84 ret = read_nonblock(STDIN_FILENO, buf, sz, &s->rfds, &n);
86 btr_add_output_pool(sit->btrp, n, sit->btrn);
90 btr_remove_node(&sit->btrn);
91 /* Revert to blocking mode if necessary. */
92 fcntl(STDIN_FILENO, F_SETFL, sit->fd_flags);
93 //btr_pool_free(sit->btrp);
98 * Register a stdin task structure.
100 * \param sit The stdin task structure to register.
101 * \param s The task will be added to this scheduler's task list.
103 * This allocates a buffer tree pool for I/O, sets up \a sit and registers a
104 * task with \a sit as context pointer.
106 void stdin_task_register(struct stdin_task *sit, struct sched *s)
109 struct task_info ti = {
111 .pre_select = stdin_pre_select,
112 .post_select = stdin_post_select,
116 sit->btrp = btr_pool_new("stdin", 128 * 1024);
118 * Both STDIN_FILENO and STDOUT_FILENO may refer to the same open file
119 * description (the terminal), and thus share the same file status
120 * flags. In order to not interfere with the stdout task, we only get
121 * the file status flags for STDIN here and save a copy. The nonblock
122 * flag is set later on the first read.
124 ret = fcntl(STDIN_FILENO, F_GETFL);
126 PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno));
130 sit->must_set_nonblock_flag = (sit->fd_flags & O_NONBLOCK) == 0;
131 sit->task = task_register(&ti, s);