file_write.c

   1 /*
   2  * Copyright (C) 2006-2011 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 int prepare_output_file(struct writer_node *wn)
  54 {
  55         struct file_write_args_info *conf = wn->conf;
  56         char *filename;
  57         int ret;
  58         struct private_file_write_data *pfwd = para_calloc(sizeof(*pfwd));
  59
  60         if (conf->filename_given)
  61                 filename = conf->filename_arg;
  62         else
  63                 filename = random_filename();
  64         ret = para_open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
  65         if (!conf->filename_given)
  66                 free(filename);
  67         if (ret < 0)
  68                 goto out;
  69         pfwd->fd = ret;
  70         ret = mark_fd_blocking(pfwd->fd);
  71         if (ret < 0)
  72                 goto out_close;
  73         wn->private_data = pfwd;
  74         return 1;
  75 out_close:
  76         close(pfwd->fd);
  77 out:
  78         free(pfwd);
  79         return ret;
  80 }
  81
  82 static void file_write_pre_select(struct sched *s, struct task *t)
  83 {
  84         struct writer_node *wn = container_of(t, struct writer_node, task);
  85         struct private_file_write_data *pfwd = wn->private_data;
  86         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  87
  88         if (ret == 0)
  89                 return;
  90         if (ret < 0 || !pfwd)
  91                 return sched_min_delay(s);
  92         para_fd_set(pfwd->fd, &s->wfds, &s->max_fileno);
  93 }
  94
  95 static void file_write_close(struct writer_node *wn)
  96 {
  97         struct private_file_write_data *pfwd = wn->private_data;
  98
  99         if (!pfwd)
 100                 return;
 101         close(pfwd->fd);
 102         free(pfwd);
 103 }
 104
 105 static void file_write_post_select(__a_unused struct sched *s,
 106                 struct task *t)
 107 {
 108         struct writer_node *wn = container_of(t, struct writer_node, task);
 109         struct private_file_write_data *pfwd = wn->private_data;
 110         struct btr_node *btrn = wn->btrn;
 111         int ret;
 112         char *buf;
 113         size_t bytes;
 114
 115         t->error = 0;
 116         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 117         if (ret <= 0)
 118                 goto out;
 119         if (!pfwd) {
 120                 ret = prepare_output_file(wn);
 121                 goto out;
 122         }
 123         if (!FD_ISSET(pfwd->fd, &s->wfds))
 124                 return;
 125         bytes = btr_next_buffer(btrn, &buf);
 126         assert(bytes > 0);
 127         //PARA_INFO_LOG("writing %zu\n", bytes);
 128         ret = write(pfwd->fd, buf, bytes);
 129         if (ret < 0)
 130                 goto out;
 131         btr_consume(btrn, ret);
 132 out:
 133         if (ret < 0)
 134                 btr_remove_node(btrn);
 135         t->error = ret;
 136 }
 137
 138 __malloc static void *file_write_parse_config_or_die(const char *options)
 139 {
 140         struct file_write_args_info *conf = para_calloc(sizeof(*conf));
 141
 142         /* exits on errors */
 143         file_cmdline_parser_string(options, conf, "file_write");
 144         return conf;
 145 }
 146
 147 static void file_write_free_config(void *conf)
 148 {
 149         file_cmdline_parser_free(conf);
 150 }
 151
 152 /** the init function of the file writer */
 153 void file_write_init(struct writer *w)
 154 {
 155         struct file_write_args_info dummy;
 156
 157         file_cmdline_parser_init(&dummy);
 158         w->pre_select = file_write_pre_select;
 159         w->post_select = file_write_post_select;
 160         w->parse_config_or_die = file_write_parse_config_or_die;
 161         w->free_config = file_write_free_config;
 162         w->close = file_write_close;
 163         w->shutdown = NULL; /* nothing to do */
 164         w->help = (struct ggo_help) {
 165                 .short_help = file_write_args_info_help,
 166                 .detailed_help = file_write_args_info_detailed_help
 167         };
 168         file_cmdline_parser_free(&dummy);
 169 }