1 /* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file stdin.c Functions that deal with reading from stdin. */
13 #include "buffer_tree.h"
17 * If there is space left in the buffer of the stdin task add STDIN_FILENO to
18 * the read fd set of s.
20 static void stdin_pre_select(struct sched
*s
, void *context
)
22 struct stdin_task
*sit
= context
;
25 ret
= btr_node_status(sit
->btrn
, 0, BTR_NT_ROOT
);
30 if (btr_pool_unused(sit
->btrp
) > 0)
31 return para_fd_set(STDIN_FILENO
, &s
->rfds
, &s
->max_fileno
);
32 sched_request_timeout_ms(100, s
);
36 * This function checks if STDIN_FILENO was included by in the read fd set of s
37 * during the previous pre_select call. If so, and if STDIN_FILENO is readable,
38 * data is read from stdin and fed into the buffer tree.
40 static int stdin_post_select(struct sched
*s
, void *context
)
42 struct stdin_task
*sit
= context
;
47 ret
= btr_node_status(sit
->btrn
, 0, BTR_NT_ROOT
);
52 sz
= btr_pool_get_buffer(sit
->btrp
, &buf
);
55 if (sit
->must_set_nonblock_flag
) {
56 ret
= mark_fd_nonblocking(STDIN_FILENO
);
59 sit
->must_set_nonblock_flag
= false;
62 * Do not use the maximal size to avoid having only a single buffer
63 * reference for the whole pool. This is bad because if that single
64 * reference can not be freed, we're stuck.
66 sz
= PARA_MIN(sz
, btr_pool_size(sit
->btrp
) / 2);
67 ret
= read_nonblock(STDIN_FILENO
, buf
, sz
, &s
->rfds
, &n
);
69 btr_add_output_pool(sit
->btrp
, n
, sit
->btrn
);
73 btr_remove_node(&sit
->btrn
);
74 /* Revert to blocking mode if necessary. */
75 fcntl(STDIN_FILENO
, F_SETFL
, sit
->fd_flags
);
76 //btr_pool_free(sit->btrp);
81 * Register a stdin task structure.
83 * \param sit The stdin task structure to register.
84 * \param s The task will be added to this scheduler's task list.
86 * This allocates a buffer tree pool for I/O, sets up \a sit and registers a
87 * task with \a sit as context pointer.
89 void stdin_task_register(struct stdin_task
*sit
, struct sched
*s
)
92 struct task_info ti
= {
94 .pre_select
= stdin_pre_select
,
95 .post_select
= stdin_post_select
,
99 sit
->btrp
= btr_pool_new("stdin", 128 * 1024);
101 * Both STDIN_FILENO and STDOUT_FILENO may refer to the same open file
102 * description (the terminal), and thus share the same file status
103 * flags. In order to not interfere with the stdout task, we only get
104 * the file status flags for STDIN here and save a copy. The nonblock
105 * flag is set later on the first read.
107 ret
= fcntl(STDIN_FILENO
, F_GETFL
);
109 PARA_EMERG_LOG("F_GETFL: %s\n", strerror(errno
));
113 sit
->must_set_nonblock_flag
= (sit
->fd_flags
& O_NONBLOCK
) == 0
114 && !isatty(STDIN_FILENO
);
115 sit
->task
= task_register(&ti
, s
);