com_stat(): Return a proper error message if an invalid option was given.
[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
12
13 #include "para.h"
14 #include "string.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "fd.h"
18 #include "error.h"
19 #include "stdin.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
35 if (sit->output_error && *sit->output_error < 0) {
36 t->error = *sit->output_error;
37 return;
38 }
39 t->error = 0;
40 sit->check_fd = 0;
41 if (sit->loaded >= sit->bufsize)
42 return;
43 sit->check_fd = 1;
44 para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
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 into the buffer of the
56 * stdin task.
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
63 if (sit->output_error && *sit->output_error < 0) {
64 t->error = *sit->output_error;
65 return;
66 }
67 t->error = 0;
68 if (!sit->check_fd)
69 return;
70 if (!FD_ISSET(STDIN_FILENO, &s->rfds))
71 return;
72 ret = read(STDIN_FILENO, sit->buf + sit->loaded, sit->bufsize - sit->loaded);
73 if (ret < 0)
74 t->error = ERRNO_TO_PARA_ERROR(errno);
75 else if (ret > 0)
76 sit->loaded += ret;
77 else
78 t->error = -E_STDIN_EOF;
79 }
80
81 /**
82 * Initialize a stdin task structure with default values.
83 *
84 * \param sit The stdin task structure.
85 *
86 * This fills in the pre/post select function pointers of the task structure
87 * given by \a sit. Moreover, the stdin file desctiptor is set to nonblocking
88 * mode and \a bufsize is initialized to 16 KB (but no buffer is allocated).
89 */
90 void stdin_set_defaults(struct stdin_task *sit)
91 {
92 int ret;
93
94 sit->bufsize = 16 * 1024,
95 sit->task.pre_select = stdin_pre_select;
96 sit->task.post_select = stdin_post_select;
97 sprintf(sit->task.status, "stdin reader");
98 ret = mark_fd_nonblocking(STDIN_FILENO);
99 if (ret >= 0)
100 return;
101 sit->output_error = NULL;
102 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
103 exit(EXIT_FAILURE);
104 }