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 static void stdin_pre_select_btr(struct sched *s, struct task *t)
  50 {
  51         struct stdin_task *sit = container_of(t, struct stdin_task, task);
  52         int ret;
  53
  54         t->error = 0;
  55         ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
  56         if (ret > 0)
  57                 para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
  58         else if (ret < 0) {
  59                 s->timeout.tv_sec = 0;
  60                 s->timeout.tv_usec = 1;
  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 = 0;
 106         ret = btr_node_status(sit->btrn, 0, BTR_NT_ROOT);
 107         if (ret < 0)
 108                 goto err;
 109         if (ret == 0)
 110                 return;
 111         if (!FD_ISSET(STDIN_FILENO, &s->rfds))
 112                 return;
 113         buf = para_malloc(STDIN_INPUT_BUFFER_SIZE);
 114         ret = read(STDIN_FILENO, buf, STDIN_INPUT_BUFFER_SIZE);
 115         //PARA_CRIT_LOG("read ret: %d\n", ret);
 116         if (ret <= 0) {
 117                 if (ret < 0)
 118                         ret = -ERRNO_TO_PARA_ERROR(errno);
 119                 else
 120                         ret = -E_STDIN_EOF;
 121                 goto err;
 122         }
 123         btr_add_output(buf, ret, sit->btrn);
 124         return;
 125 err:
 126         free(buf);
 127         btr_remove_node(sit->btrn);
 128         t->error = ret;
 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 }