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