btr: Remove btr_free_node().
[paraslash.git] / stdin.c
1 /*
2 * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file stdin.c Functions that deal with reading from stdin. */
8
9 #include <assert.h>
10 #include <regex.h>
11
12 #include "para.h"
13 #include "list.h"
14 #include "sched.h"
15 #include "fd.h"
16 #include "error.h"
17 #include "stdin.h"
18 #include "buffer_tree.h"
19 #include "string.h"
20
21 /**
22 * The pre_select function of the stdin task.
23 *
24 * \param s The scheduler this task was registered to.
25 * \param t The task structure of the stdin task.
26 *
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
29 * of \a s.
30 */
31 static void stdin_pre_select(struct sched *s, struct task *t)
32 {
33 struct stdin_task *sit = container_of(t, struct stdin_task, task);
34 int ret;
35
36 t->error = 0;
37 ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
38 if (ret < 0)
39 sched_min_delay(s);
40 if (ret <= 0)
41 return;
42 if (btr_pool_unused(sit->btrp) > 0)
43 return para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
44 sched_request_timeout_ms(100, s);
45 }
46
47 /**
48 * The post select function of the stdin task.
49 *
50 * \param s The scheduler this task was registered to.
51 * \param t The task structure of the stdin task.
52 *
53 * This function checks if \p STDIN_FILENO was included by in the read fd set
54 * of \a s during the previous pre_select call. If yes, and \p STDIN_FILENO
55 * appears to be readable, data is read from stdin and fed into the buffer
56 * tree.
57 */
58 static void stdin_post_select(struct sched *s, struct task *t)
59 {
60 struct stdin_task *sit = container_of(t, struct stdin_task, task);
61 ssize_t ret;
62 size_t sz, n;
63 char *buf = NULL;
64
65 t->error = 0;
66 ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
67 if (ret < 0)
68 goto err;
69 if (ret == 0)
70 return;
71 sz = btr_pool_get_buffer(sit->btrp, &buf);
72 if (sz == 0)
73 return;
74 /*
75 * Do not use the maximal size to avoid having only a single buffer
76 * reference for the whole pool. This is bad because if that single
77 * reference can not be freed, we're stuck.
78 */
79 sz = PARA_MIN(sz, btr_pool_size(sit->btrp) / 2);
80 ret = read_nonblock(STDIN_FILENO, buf, sz, &s->rfds, &n);
81 if (n > 0)
82 btr_add_output_pool(sit->btrp, n, sit->btrn);
83 if (ret >= 0)
84 return;
85 err:
86 btr_remove_node(&sit->btrn);
87 //btr_pool_free(sit->btrp);
88 t->error = ret;
89 }
90
91 /**
92 * Initialize a stdin task structure with default values.
93 *
94 * \param sit The stdin task structure.
95 *
96 * This fills in the pre/post select function pointers of the task structure
97 * given by \a sit. Moreover, the stdin file desctiptor is set to nonblocking
98 * mode, and a buffer tree is created.
99 */
100 void stdin_set_defaults(struct stdin_task *sit)
101 {
102 int ret;
103
104 sit->task.pre_select = stdin_pre_select;
105 sit->task.post_select = stdin_post_select;
106 sit->btrp = btr_pool_new("stdin", 128 * 1024);
107 sprintf(sit->task.status, "stdin reader");
108 ret = mark_fd_nonblocking(STDIN_FILENO);
109 if (ret >= 0)
110 return;
111 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
112 exit(EXIT_FAILURE);
113 }