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 = container_of(t, struct stdin_task, task);
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 = container_of(t, struct stdin_task, task);
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 * Initialize a stdin task structure with default values.
100 * \param sit The stdin task structure.
102 * This fills in the pre/post select function pointers of the task structure
103 * given by \a sit and creates a buffer tree for I/O.
105 void stdin_set_defaults(struct stdin_task *sit)
109 sit->task.pre_select = stdin_pre_select;
110 sit->task.post_select = stdin_post_select;
111 sit->btrp = btr_pool_new("stdin", 128 * 1024);
112 sprintf(sit->task.status, "stdin reader");
114 * Both STDIN_FILENO and STDOUT_FILENO may refer to the same open file
115 * description (the terminal), and thus share the same file status
116 * flags. In order to not interfere with the stdout task, we only get
117 * the file status flags for STDIN here and save a copy. The nonblock
118 * flag is set later on the first read.
120 ret = fcntl(STDIN_FILENO, F_GETFL);
122 PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno));
126 sit->must_set_nonblock_flag = (sit->fd_flags & O_NONBLOCK) == 0;