file_write.c

   1 /*
   2  * Copyright (C) 2006-2010 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file file_write.c simple output plugin for testing purposes */
   8
   9 #include <regex.h>
  10 #include <sys/types.h>
  11 #include <dirent.h>
  12 #include <sys/time.h>
  13 #include <stdbool.h>
  14
  15 #include "para.h"
  16 #include "list.h"
  17 #include "sched.h"
  18 #include "ggo.h"
  19 #include "buffer_tree.h"
  20 #include "write.h"
  21 #include "write_common.h"
  22 #include "string.h"
  23 #include "fd.h"
  24 #include "file_write.cmdline.h"
  25 #include "error.h"
  26
  27 /** Data specific to the file writer. */
  28 struct private_file_write_data {
  29         /** The file descriptor of the output file. */
  30         int fd;
  31 };
  32
  33 /*
  34  * Get a random filename.
  35  *
  36  * This is by no means a secure way to create temporary files in a hostile
  37  * directory like \p /tmp. However, we use it only for creating temp files in
  38  * ~/.paraslash, for which it is OK. Result must be freed by the caller.
  39  */
  40 __must_check __malloc static char *random_filename(void)
  41 {
  42         char *result, *home = para_homedir();
  43         struct timeval tv;
  44
  45         gettimeofday(&tv, NULL);
  46         srandom(tv.tv_usec);
  47         result = make_message("%s/.paraslash/%08lu", home,
  48                 para_random(99999999));
  49         free(home);
  50         return result;
  51 }
  52
  53 static void file_write_open(struct writer_node *wn)
  54 {
  55         struct private_file_write_data *pfwd = para_calloc(sizeof(*pfwd));
  56
  57         wn->private_data = pfwd;
  58         pfwd->fd = -1;
  59 }
  60
  61 static int prepare_output_file(struct writer_node *wn)
  62 {
  63         struct file_write_args_info *conf = wn->conf;
  64         struct private_file_write_data *pfwd = wn->private_data;
  65         char *filename;
  66         int ret;
  67
  68         if (conf->filename_given)
  69                 filename = conf->filename_arg;
  70         else
  71                 filename = random_filename();
  72         ret = para_open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
  73         if (!conf->filename_given)
  74                 free(filename);
  75         if (ret < 0)
  76                 goto out;
  77         pfwd->fd = ret;
  78         ret = mark_fd_blocking(pfwd->fd);
  79         if (ret >= 0)
  80                 return 1;
  81         close(pfwd->fd);
  82 out:
  83         free(pfwd);
  84         return ret;
  85 }
  86
  87 static void file_write_pre_select(struct sched *s, struct task *t)
  88 {
  89         struct writer_node *wn = container_of(t, struct writer_node, task);
  90         struct private_file_write_data *pfwd = wn->private_data;
  91         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  92
  93         if (ret == 0)
  94                 return;
  95         if (ret < 0 || pfwd->fd < 0)
  96                 return sched_min_delay(s);
  97         para_fd_set(pfwd->fd, &s->wfds, &s->max_fileno);
  98 }
  99
 100 static void file_write_close(struct writer_node *wn)
 101 {
 102         struct private_file_write_data *pfwd = wn->private_data;
 103
 104         if (pfwd->fd >= 0)
 105                 close(pfwd->fd);
 106         free(pfwd);
 107 }
 108
 109 static void file_write_post_select(__a_unused struct sched *s,
 110                 struct task *t)
 111 {
 112         struct writer_node *wn = container_of(t, struct writer_node, task);
 113         struct private_file_write_data *pfwd = wn->private_data;
 114         struct btr_node *btrn = wn->btrn;
 115         int ret;
 116         char *buf;
 117         size_t bytes;
 118
 119         t->error = 0;
 120         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 121         if (ret <= 0)
 122                 goto out;
 123         if (pfwd->fd < 0) {
 124                 ret = prepare_output_file(wn);
 125                 if (ret < 0)
 126                         goto out;
 127         }
 128         if (!FD_ISSET(pfwd->fd, &s->wfds))
 129                 return;
 130         bytes = btr_next_buffer(btrn, &buf);
 131         assert(bytes > 0);
 132         //PARA_INFO_LOG("writing %zu\n", bytes);
 133         ret = write(pfwd->fd, buf, bytes);
 134         if (ret < 0)
 135                 goto out;
 136         btr_consume(btrn, ret);
 137 out:
 138         if (ret < 0)
 139                 btr_remove_node(btrn);
 140         t->error = ret;
 141 }
 142
 143 __malloc static void *file_write_parse_config_or_die(const char *options)
 144 {
 145         struct file_write_args_info *conf = para_calloc(sizeof(*conf));
 146
 147         /* exits on errors */
 148         file_cmdline_parser_string(options, conf, "file_write");
 149         return conf;
 150 }
 151
 152 static void file_write_free_config(void *conf)
 153 {
 154         file_cmdline_parser_free(conf);
 155 }
 156
 157 /** the init function of the file writer */
 158 void file_write_init(struct writer *w)
 159 {
 160         struct file_write_args_info dummy;
 161
 162         file_cmdline_parser_init(&dummy);
 163         w->open = file_write_open;
 164         w->pre_select = file_write_pre_select;
 165         w->post_select = file_write_post_select;
 166         w->parse_config_or_die = file_write_parse_config_or_die;
 167         w->free_config = file_write_free_config;
 168         w->close = file_write_close;
 169         w->shutdown = NULL; /* nothing to do */
 170         w->help = (struct ggo_help) {
 171                 .short_help = file_write_args_info_help,
 172                 .detailed_help = file_write_args_info_detailed_help
 173         };
 174         file_cmdline_parser_free(&dummy);
 175 }