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1 | office | 1 | /** |
2 | * @file sys_watch_directory.c |
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3 | * @author Ambroz Bizjak <ambrop7@gmail.com> |
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4 | * |
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5 | * @section LICENSE |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * 3. Neither the name of the author nor the |
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15 | * names of its contributors may be used to endorse or promote products |
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16 | * derived from this software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
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19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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21 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
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22 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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24 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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25 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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27 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | * |
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29 | * @section DESCRIPTION |
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30 | * |
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31 | * Directory watcher. |
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32 | * |
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33 | * Synopsis: sys.watch_directory(string dir) |
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34 | * Description: reports directory entry events. Transitions up when an event is detected, and |
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35 | * goes down waiting for the next event when sys.watch_directory::nextevent() is called. |
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36 | * The directory is first scanned and "added" events are reported for all files. |
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37 | * Variables: |
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38 | * string event_type - what happened with the file: "added", "removed" or "changed" |
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39 | * string filename - name of the file in the directory the event refers to |
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40 | * string filepath - "dir/filename" |
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41 | * |
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42 | * Synopsis: sys.watch_directory::nextevent() |
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43 | * Description: makes the watch_directory module transition down in order to report the next event. |
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44 | */ |
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45 | |||
46 | #include <stdlib.h> |
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47 | #include <string.h> |
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48 | #include <unistd.h> |
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49 | #include <sys/inotify.h> |
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50 | #include <sys/types.h> |
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51 | #include <dirent.h> |
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52 | #include <errno.h> |
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53 | |||
54 | #include <misc/nonblocking.h> |
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55 | #include <misc/concat_strings.h> |
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56 | |||
57 | #include <ncd/module_common.h> |
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58 | |||
59 | #include <generated/blog_channel_ncd_sys_watch_directory.h> |
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60 | |||
61 | #define MAX_INOTIFY_EVENTS 128 |
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62 | |||
63 | struct instance { |
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64 | NCDModuleInst *i; |
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65 | NCDValNullTermString dir_nts; |
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66 | DIR *dir_handle; |
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67 | int inotify_fd; |
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68 | BFileDescriptor bfd; |
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69 | struct inotify_event events[MAX_INOTIFY_EVENTS]; |
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70 | int events_count; |
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71 | int events_index; |
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72 | int processing; |
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73 | const char *processing_file; |
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74 | const char *processing_type; |
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75 | }; |
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76 | |||
77 | static void instance_free (struct instance *o, int is_error); |
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78 | |||
79 | static void next_dir_event (struct instance *o) |
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80 | { |
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81 | ASSERT(!o->processing) |
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82 | ASSERT(o->dir_handle) |
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83 | |||
84 | struct dirent *entry; |
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85 | |||
86 | do { |
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87 | // get next entry |
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88 | errno = 0; |
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89 | if (!(entry = readdir(o->dir_handle))) { |
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90 | if (errno != 0) { |
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91 | ModuleLog(o->i, BLOG_ERROR, "readdir failed"); |
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92 | instance_free(o, 1); |
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93 | return; |
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94 | } |
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95 | |||
96 | // close directory |
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97 | if (closedir(o->dir_handle) < 0) { |
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98 | ModuleLog(o->i, BLOG_ERROR, "closedir failed"); |
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99 | o->dir_handle = NULL; |
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100 | instance_free(o, 1); |
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101 | return; |
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102 | } |
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103 | |||
104 | // set no dir handle |
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105 | o->dir_handle = NULL; |
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106 | |||
107 | // start receiving inotify events |
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108 | BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, BREACTOR_READ); |
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109 | return; |
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110 | } |
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111 | } while (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..")); |
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112 | |||
113 | // set event |
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114 | o->processing_file = entry->d_name; |
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115 | o->processing_type = "added"; |
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116 | o->processing = 1; |
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117 | |||
118 | // signal up |
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119 | NCDModuleInst_Backend_Up(o->i); |
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120 | } |
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121 | |||
122 | static void assert_inotify_event (struct instance *o) |
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123 | { |
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124 | ASSERT(o->events_index < o->events_count) |
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125 | ASSERT(o->events[o->events_index].len % sizeof(o->events[0]) == 0) |
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126 | ASSERT(o->events[o->events_index].len / sizeof(o->events[0]) <= o->events_count - (o->events_index + 1)) |
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127 | } |
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128 | |||
129 | static const char * translate_inotify_event (struct instance *o) |
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130 | { |
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131 | assert_inotify_event(o); |
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132 | |||
133 | struct inotify_event *event = &o->events[o->events_index]; |
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134 | |||
135 | if (strlen(event->name) > 0) { |
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136 | if ((event->mask & (IN_CREATE | IN_MOVED_TO))) { |
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137 | return "added"; |
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138 | } |
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139 | if ((event->mask & (IN_DELETE | IN_MOVED_FROM))) { |
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140 | return "removed"; |
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141 | } |
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142 | if ((event->mask & IN_MODIFY)) { |
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143 | return "changed"; |
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144 | } |
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145 | } |
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146 | |||
147 | return NULL; |
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148 | } |
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149 | |||
150 | static void skip_inotify_event (struct instance *o) |
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151 | { |
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152 | assert_inotify_event(o); |
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153 | |||
154 | o->events_index += 1 + o->events[o->events_index].len / sizeof(o->events[0]); |
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155 | } |
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156 | |||
157 | static void next_inotify_event (struct instance *o) |
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158 | { |
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159 | ASSERT(!o->processing) |
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160 | ASSERT(!o->dir_handle) |
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161 | |||
162 | // skip any bad events |
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163 | while (o->events_index < o->events_count && !translate_inotify_event(o)) { |
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164 | ModuleLog(o->i, BLOG_ERROR, "unknown inotify event"); |
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165 | skip_inotify_event(o); |
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166 | } |
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167 | |||
168 | if (o->events_index == o->events_count) { |
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169 | // wait for more events |
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170 | BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, BREACTOR_READ); |
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171 | return; |
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172 | } |
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173 | |||
174 | // set event |
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175 | o->processing_file = o->events[o->events_index].name; |
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176 | o->processing_type = translate_inotify_event(o); |
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177 | o->processing = 1; |
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178 | |||
179 | // consume this event |
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180 | skip_inotify_event(o); |
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181 | |||
182 | // signal up |
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183 | NCDModuleInst_Backend_Up(o->i); |
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184 | } |
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185 | |||
186 | static void inotify_fd_handler (struct instance *o, int events) |
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187 | { |
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188 | if (o->processing) { |
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189 | ModuleLog(o->i, BLOG_ERROR, "file descriptor error"); |
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190 | instance_free(o, 1); |
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191 | return; |
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192 | } |
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193 | |||
194 | ASSERT(!o->dir_handle) |
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195 | |||
196 | int res = read(o->inotify_fd, o->events, sizeof(o->events)); |
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197 | if (res < 0) { |
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198 | ModuleLog(o->i, BLOG_ERROR, "read failed"); |
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199 | instance_free(o, 1); |
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200 | return; |
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201 | } |
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202 | |||
203 | // stop waiting for inotify events |
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204 | BReactor_SetFileDescriptorEvents(o->i->params->iparams->reactor, &o->bfd, 0); |
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205 | |||
206 | ASSERT(res <= sizeof(o->events)) |
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207 | ASSERT(res % sizeof(o->events[0]) == 0) |
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208 | |||
209 | // setup buffer state |
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210 | o->events_count = res / sizeof(o->events[0]); |
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211 | o->events_index = 0; |
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212 | |||
213 | // process inotify events |
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214 | next_inotify_event(o); |
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215 | } |
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216 | |||
217 | static void next_event (struct instance *o) |
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218 | { |
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219 | ASSERT(o->processing) |
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220 | |||
221 | // set not processing |
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222 | o->processing = 0; |
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223 | |||
224 | // signal down |
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225 | NCDModuleInst_Backend_Down(o->i); |
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226 | |||
227 | if (o->dir_handle) { |
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228 | next_dir_event(o); |
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229 | return; |
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230 | } else { |
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231 | next_inotify_event(o); |
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232 | return; |
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233 | } |
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234 | } |
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235 | |||
236 | static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params) |
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237 | { |
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238 | struct instance *o = vo; |
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239 | o->i = i; |
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240 | |||
241 | // check arguments |
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242 | NCDValRef dir_arg; |
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243 | if (!NCDVal_ListRead(params->args, 1, &dir_arg)) { |
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244 | ModuleLog(o->i, BLOG_ERROR, "wrong arity"); |
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245 | goto fail0; |
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246 | } |
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247 | if (!NCDVal_IsStringNoNulls(dir_arg)) { |
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248 | ModuleLog(o->i, BLOG_ERROR, "wrong type"); |
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249 | goto fail0; |
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250 | } |
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251 | |||
252 | // null terminate dir |
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253 | if (!NCDVal_StringNullTerminate(dir_arg, &o->dir_nts)) { |
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254 | ModuleLog(o->i, BLOG_ERROR, "NCDVal_StringNullTerminate failed"); |
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255 | goto fail0; |
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256 | } |
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257 | |||
258 | // open inotify |
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259 | if ((o->inotify_fd = inotify_init()) < 0) { |
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260 | ModuleLog(o->i, BLOG_ERROR, "inotify_init failed"); |
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261 | goto fail1; |
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262 | } |
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263 | |||
264 | // add watch |
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265 | if (inotify_add_watch(o->inotify_fd, o->dir_nts.data, IN_CREATE | IN_DELETE | IN_MODIFY | IN_MOVED_FROM | IN_MOVED_TO) < 0) { |
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266 | ModuleLog(o->i, BLOG_ERROR, "inotify_add_watch failed"); |
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267 | goto fail2; |
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268 | } |
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269 | |||
270 | // set non-blocking |
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271 | if (!badvpn_set_nonblocking(o->inotify_fd)) { |
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272 | ModuleLog(o->i, BLOG_ERROR, "badvpn_set_nonblocking failed"); |
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273 | goto fail2; |
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274 | } |
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275 | |||
276 | // init BFileDescriptor |
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277 | BFileDescriptor_Init(&o->bfd, o->inotify_fd, (BFileDescriptor_handler)inotify_fd_handler, o); |
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278 | if (!BReactor_AddFileDescriptor(o->i->params->iparams->reactor, &o->bfd)) { |
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279 | ModuleLog(o->i, BLOG_ERROR, "BReactor_AddFileDescriptor failed"); |
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280 | goto fail2; |
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281 | } |
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282 | |||
283 | // open directory |
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284 | if (!(o->dir_handle = opendir(o->dir_nts.data))) { |
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285 | ModuleLog(o->i, BLOG_ERROR, "opendir failed"); |
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286 | goto fail3; |
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287 | } |
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288 | |||
289 | // set not processing |
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290 | o->processing = 0; |
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291 | |||
292 | // read first directory entry |
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293 | next_dir_event(o); |
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294 | return; |
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295 | |||
296 | fail3: |
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297 | BReactor_RemoveFileDescriptor(o->i->params->iparams->reactor, &o->bfd); |
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298 | fail2: |
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299 | if (close(o->inotify_fd) < 0) { |
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300 | ModuleLog(o->i, BLOG_ERROR, "close failed"); |
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301 | } |
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302 | fail1: |
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303 | NCDValNullTermString_Free(&o->dir_nts); |
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304 | fail0: |
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305 | NCDModuleInst_Backend_DeadError(i); |
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306 | } |
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307 | |||
308 | void instance_free (struct instance *o, int is_error) |
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309 | { |
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310 | // close directory |
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311 | if (o->dir_handle) { |
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312 | if (closedir(o->dir_handle) < 0) { |
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313 | ModuleLog(o->i, BLOG_ERROR, "closedir failed"); |
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314 | } |
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315 | } |
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316 | |||
317 | // free BFileDescriptor |
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318 | BReactor_RemoveFileDescriptor(o->i->params->iparams->reactor, &o->bfd); |
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319 | |||
320 | // close inotify |
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321 | if (close(o->inotify_fd) < 0) { |
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322 | ModuleLog(o->i, BLOG_ERROR, "close failed"); |
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323 | } |
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324 | |||
325 | // free dir nts |
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326 | NCDValNullTermString_Free(&o->dir_nts); |
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327 | |||
328 | if (is_error) { |
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329 | NCDModuleInst_Backend_DeadError(o->i); |
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330 | } else { |
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331 | NCDModuleInst_Backend_Dead(o->i); |
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332 | } |
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333 | } |
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334 | |||
335 | static void func_die (void *vo) |
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336 | { |
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337 | struct instance *o = vo; |
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338 | instance_free(o, 0); |
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339 | } |
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340 | |||
341 | static int func_getvar (void *vo, const char *name, NCDValMem *mem, NCDValRef *out) |
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342 | { |
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343 | struct instance *o = vo; |
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344 | ASSERT(o->processing) |
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345 | |||
346 | if (!strcmp(name, "event_type")) { |
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347 | *out = NCDVal_NewString(mem, o->processing_type); |
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348 | return 1; |
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349 | } |
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350 | |||
351 | if (!strcmp(name, "filename")) { |
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352 | *out = NCDVal_NewString(mem, o->processing_file); |
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353 | return 1; |
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354 | } |
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355 | |||
356 | if (!strcmp(name, "filepath")) { |
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357 | char *str = concat_strings(3, o->dir_nts.data, "/", o->processing_file); |
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358 | if (!str) { |
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359 | ModuleLog(o->i, BLOG_ERROR, "concat_strings failed"); |
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360 | goto fail; |
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361 | } |
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362 | |||
363 | *out = NCDVal_NewString(mem, str); |
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364 | |||
365 | free(str); |
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366 | return 1; |
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367 | } |
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368 | |||
369 | return 0; |
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370 | |||
371 | fail: |
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372 | *out = NCDVal_NewInvalid(); |
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373 | return 1; |
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374 | } |
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375 | |||
376 | static void nextevent_func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params) |
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377 | { |
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378 | // check arguments |
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379 | if (!NCDVal_ListRead(params->args, 0)) { |
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380 | ModuleLog(i, BLOG_ERROR, "wrong arity"); |
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381 | goto fail0; |
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382 | } |
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383 | |||
384 | // get method object |
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385 | struct instance *mo = NCDModuleInst_Backend_GetUser((NCDModuleInst *)params->method_user); |
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386 | |||
387 | // make sure we are currently reporting an event |
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388 | if (!mo->processing) { |
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389 | ModuleLog(i, BLOG_ERROR, "not reporting an event"); |
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390 | goto fail0; |
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391 | } |
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392 | |||
393 | // signal up. |
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394 | // Do it before finishing the event so our process does not advance any further if |
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395 | // we would be killed the event provider going down. |
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396 | NCDModuleInst_Backend_Up(i); |
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397 | |||
398 | // wait for next event |
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399 | next_event(mo); |
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400 | return; |
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401 | |||
402 | fail0: |
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403 | NCDModuleInst_Backend_DeadError(i); |
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404 | } |
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405 | |||
406 | static struct NCDModule modules[] = { |
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407 | { |
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408 | .type = "sys.watch_directory", |
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409 | .func_new2 = func_new, |
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410 | .func_die = func_die, |
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411 | .func_getvar = func_getvar, |
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412 | .alloc_size = sizeof(struct instance) |
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413 | }, { |
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414 | .type = "sys.watch_directory::nextevent", |
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415 | .func_new2 = nextevent_func_new |
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416 | }, { |
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417 | .type = NULL |
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418 | } |
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419 | }; |
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420 | |||
421 | const struct NCDModuleGroup ncdmodule_sys_watch_directory = { |
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422 | .modules = modules |
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423 | }; |