[btr] Split btr_del_node() into two functions.
[paraslash.git] / stdin.c
1 /*
2 * Copyright (C) 2006-2009 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 <dirent.h> /* readdir() */
10 #include <assert.h>
11 #include <stdbool.h>
12 #include <regex.h>
13
14 #include "para.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "fd.h"
18 #include "error.h"
19 #include "stdin.h"
20 #include "buffer_tree.h"
21 #include "string.h"
22
23 /**
24 * The pre_select function of the stdin task.
25 *
26 * \param s The scheduler this task was registered to.
27 * \param t The task structure of the stdin task.
28 *
29 * This function is always successful. If there is space left in the
30 * buffer of the stdin task, it adds \p STDIN_FILENO to the read fd set
31 * of \a s.
32 */
33 static void stdin_pre_select(struct sched *s, struct task *t)
34 {
35 struct stdin_task *sit = container_of(t, struct stdin_task, task);
36
37 if (sit->output_error && *sit->output_error < 0) {
38 t->error = *sit->output_error;
39 return;
40 }
41 t->error = 0;
42 sit->check_fd = 0;
43 if (sit->loaded >= sit->bufsize)
44 return;
45 sit->check_fd = 1;
46 para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
47 }
48
49 #define STDIN_MAX_PENDING (100 * 1024)
50
51 static void stdin_pre_select_btr(struct sched *s, struct task *t)
52 {
53 struct stdin_task *sit = container_of(t, struct stdin_task, task);
54
55 t->error = 0;
56 if (btr_bytes_pending(sit->btrn) > STDIN_MAX_PENDING)
57 sit->check_fd = 0;
58 else {
59 sit->check_fd = 1;
60 para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
61 }
62 }
63
64 /**
65 * The post select function of the stdin task.
66 *
67 * \param s The scheduler this task was registered to.
68 * \param t The task structure of the stdin task.
69 *
70 * This function checks if \p STDIN_FILENO was included by in the read fd set
71 * of \a s during the previous pre_select call. If yes, and \p STDIN_FILENO
72 * appears to be readable, data is read from stdin into the buffer of the
73 * stdin task.
74 */
75 static void stdin_post_select(struct sched *s, struct task *t)
76 {
77 struct stdin_task *sit = container_of(t, struct stdin_task, task);
78 ssize_t ret;
79
80 if (sit->output_error && *sit->output_error < 0) {
81 t->error = *sit->output_error;
82 return;
83 }
84 t->error = 0;
85 if (!sit->check_fd)
86 return;
87 if (!FD_ISSET(STDIN_FILENO, &s->rfds))
88 return;
89 ret = read(STDIN_FILENO, sit->buf + sit->loaded, sit->bufsize - sit->loaded);
90 if (ret < 0)
91 t->error = ERRNO_TO_PARA_ERROR(errno);
92 else if (ret > 0)
93 sit->loaded += ret;
94 else
95 t->error = -E_STDIN_EOF;
96 }
97
98 #define STDIN_INPUT_BUFFER_SIZE (1024 * 32)
99 static void stdin_post_select_btr(struct sched *s, struct task *t)
100 {
101 struct stdin_task *sit = container_of(t, struct stdin_task, task);
102 ssize_t ret;
103 char *buf = NULL;
104
105 t->error = -E_STDIN_NO_CHILD;
106 if (btr_no_children(sit->btrn))
107 goto err;
108
109 t->error = 0;
110 if (!sit->check_fd)
111 return;
112 if (!FD_ISSET(STDIN_FILENO, &s->rfds))
113 return;
114
115 buf = para_malloc(STDIN_INPUT_BUFFER_SIZE);
116 ret = read(STDIN_FILENO, buf, STDIN_INPUT_BUFFER_SIZE);
117 //PARA_CRIT_LOG("read ret: %d\n", ret);
118 if (ret < 0)
119 t->error = -ERRNO_TO_PARA_ERROR(errno);
120 if (ret == 0)
121 t->error = -E_STDIN_EOF;
122 if (t->error < 0)
123 goto err;
124 btr_add_output(buf, ret, sit->btrn);
125 return;
126 err:
127 free(buf);
128 btr_remove_node(sit->btrn);
129 }
130
131 /**
132 * Initialize a stdin task structure with default values.
133 *
134 * \param sit The stdin task structure.
135 *
136 * This fills in the pre/post select function pointers of the task structure
137 * given by \a sit. Moreover, the stdin file desctiptor is set to nonblocking
138 * mode and \a bufsize is initialized to 16 KB (but no buffer is allocated).
139 */
140 void stdin_set_defaults(struct stdin_task *sit)
141 {
142 int ret;
143
144 sit->bufsize = 32 * 1024;
145 if (sit->btrn) {
146 sit->task.pre_select = stdin_pre_select_btr;
147 sit->task.post_select = stdin_post_select_btr;
148 } else {
149 sit->task.pre_select = stdin_pre_select;
150 sit->task.post_select = stdin_post_select;
151 }
152 sprintf(sit->task.status, "stdin reader");
153 ret = mark_fd_nonblocking(STDIN_FILENO);
154 if (ret >= 0)
155 return;
156 sit->output_error = NULL;
157 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
158 exit(EXIT_FAILURE);
159 }