ncd :add sys.watch_directory module

CMakeLists.txt

@@ -84,6 +84,12 @@ else ()
             add_definitions(-DBADVPN_USE_LINUX_INPUT)
             set(BADVPN_USE_LINUX_INPUT 1)
         endif ()
+
+        check_include_files(sys/inotify.h HAVE_SYS_INOTIFY_H)
+        if (HAVE_SYS_INOTIFY_H)
+            add_definitions(-DBADVPN_USE_INOTIFY)
+            set(BADVPN_USE_INOTIFY 1)
+        endif ()
     elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
         add_definitions(-DBADVPN_FREEBSD)
 

blog_channels.txt

@@ -33,6 +33,7 @@ ncd_net_ipv4_addr 4
 ncd_net_ipv4_dhcp 4
 ncd_net_ipv4_route 4
 ncd_sys_evdev 4
+ncd_sys_watch_directory 4
 StreamPeerIO 4
 DatagramPeerIO 4
 BReactor 3

generated/blog_channel_ncd_sys_watch_directory.h

@@ -0,0 +1,4 @@
+#ifdef BLOG_CURRENT_CHANNEL
+#undef BLOG_CURRENT_CHANNEL
+#endif
+#define BLOG_CURRENT_CHANNEL BLOG_CHANNEL_ncd_sys_watch_directory

generated/blog_channels_defines.h

@@ -33,31 +33,32 @@
 #define BLOG_CHANNEL_ncd_net_ipv4_dhcp 32
 #define BLOG_CHANNEL_ncd_net_ipv4_route 33
 #define BLOG_CHANNEL_ncd_sys_evdev 34
-#define BLOG_CHANNEL_StreamPeerIO 35
-#define BLOG_CHANNEL_DatagramPeerIO 36
-#define BLOG_CHANNEL_BReactor 37
-#define BLOG_CHANNEL_BSignal 38
-#define BLOG_CHANNEL_FragmentProtoAssembler 39
-#define BLOG_CHANNEL_BPredicate 40
-#define BLOG_CHANNEL_ServerConnection 41
-#define BLOG_CHANNEL_Listener 42
-#define BLOG_CHANNEL_DataProto 43
-#define BLOG_CHANNEL_FrameDecider 44
-#define BLOG_CHANNEL_BSocksClient 45
-#define BLOG_CHANNEL_BDHCPClientCore 46
-#define BLOG_CHANNEL_BDHCPClient 47
-#define BLOG_CHANNEL_NCDIfConfig 48
-#define BLOG_CHANNEL_BUnixSignal 49
-#define BLOG_CHANNEL_BProcess 50
-#define BLOG_CHANNEL_StreamSocketSink 51
-#define BLOG_CHANNEL_StreamSocketSource 52
-#define BLOG_CHANNEL_DatagramSocketSink 53
-#define BLOG_CHANNEL_DatagramSocketSource 54
-#define BLOG_CHANNEL_PRStreamSink 55
-#define BLOG_CHANNEL_PRStreamSource 56
-#define BLOG_CHANNEL_BSocketPRFileDesc 57
-#define BLOG_CHANNEL_PacketProtoDecoder 58
-#define BLOG_CHANNEL_DPRelay 59
-#define BLOG_CHANNEL_BThreadWork 60
-#define BLOG_CHANNEL_DPReceive 61
-#define BLOG_NUM_CHANNELS 62
+#define BLOG_CHANNEL_ncd_sys_watch_directory 35
+#define BLOG_CHANNEL_StreamPeerIO 36
+#define BLOG_CHANNEL_DatagramPeerIO 37
+#define BLOG_CHANNEL_BReactor 38
+#define BLOG_CHANNEL_BSignal 39
+#define BLOG_CHANNEL_FragmentProtoAssembler 40
+#define BLOG_CHANNEL_BPredicate 41
+#define BLOG_CHANNEL_ServerConnection 42
+#define BLOG_CHANNEL_Listener 43
+#define BLOG_CHANNEL_DataProto 44
+#define BLOG_CHANNEL_FrameDecider 45
+#define BLOG_CHANNEL_BSocksClient 46
+#define BLOG_CHANNEL_BDHCPClientCore 47
+#define BLOG_CHANNEL_BDHCPClient 48
+#define BLOG_CHANNEL_NCDIfConfig 49
+#define BLOG_CHANNEL_BUnixSignal 50
+#define BLOG_CHANNEL_BProcess 51
+#define BLOG_CHANNEL_StreamSocketSink 52
+#define BLOG_CHANNEL_StreamSocketSource 53
+#define BLOG_CHANNEL_DatagramSocketSink 54
+#define BLOG_CHANNEL_DatagramSocketSource 55
+#define BLOG_CHANNEL_PRStreamSink 56
+#define BLOG_CHANNEL_PRStreamSource 57
+#define BLOG_CHANNEL_BSocketPRFileDesc 58
+#define BLOG_CHANNEL_PacketProtoDecoder 59
+#define BLOG_CHANNEL_DPRelay 60
+#define BLOG_CHANNEL_BThreadWork 61
+#define BLOG_CHANNEL_DPReceive 62
+#define BLOG_NUM_CHANNELS 63

generated/blog_channels_list.h

@@ -33,6 +33,7 @@
 {.name = "ncd_net_ipv4_dhcp", .loglevel = 4},
 {.name = "ncd_net_ipv4_route", .loglevel = 4},
 {.name = "ncd_sys_evdev", .loglevel = 4},
+{.name = "ncd_sys_watch_directory", .loglevel = 4},
 {.name = "StreamPeerIO", .loglevel = 4},
 {.name = "DatagramPeerIO", .loglevel = 4},
 {.name = "BReactor", .loglevel = 3},

ncd/CMakeLists.txt

@@ -15,6 +15,12 @@ if (BADVPN_USE_LINUX_INPUT)
     )
 endif ()
 
+if (BADVPN_USE_INOTIFY)
+    list(APPEND NCD_ADDITIONAL_SOURCES
+        modules/sys_watch_directory.c
+    )
+endif ()
+
 add_executable(badvpn-ncd
     ncd.c
     NCDValue.c

ncd/modules/modules.h

@@ -61,6 +61,9 @@ extern const struct NCDModuleGroup ncdmodule_net_ipv4_dhcp;
 #ifdef BADVPN_USE_LINUX_INPUT
 extern const struct NCDModuleGroup ncdmodule_sys_evdev;
 #endif
+#ifdef BADVPN_USE_INOTIFY
+extern const struct NCDModuleGroup ncdmodule_sys_watch_directory;
+#endif
 
 static const struct NCDModuleGroup *ncd_modules[] = {
     &ncdmodule_var,
@@ -96,6 +99,9 @@ static const struct NCDModuleGroup *ncd_modules[] = {
     &ncdmodule_net_ipv4_dhcp,
 #ifdef BADVPN_USE_LINUX_INPUT
     &ncdmodule_sys_evdev,
+#endif
+#ifdef BADVPN_USE_INOTIFY
+    &ncdmodule_sys_watch_directory,
 #endif
     NULL
 };

ncd/modules/sys_watch_directory.c

@@ -0,0 +1,375 @@
+/**
+ * @file sys_watch_directory.c
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * This file is part of BadVPN.
+ * 
+ * BadVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ * 
+ * BadVPN is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * 
+ * @section DESCRIPTION
+ * 
+ * Directory watcher.
+ * 
+ * Synopsis: sys.watch_directory(string dir)
+ * Description: reports directory entry events. Transitions up when an event is detected, and
+ *   goes down waiting for the next event when sys.watch_directory::nextevent() is called.
+ * Variables:
+ *   string event_type - what happened with the file: "added", "removed" or "changed"
+ *   string filename - name of the file in the directory the event refers to
+ *   string filepath - "dir/filename"
+ * 
+ * Synopsis: sys.watch_directory::nextevent()
+ * Description: makes the watch_directory module transition down in order to report the next event.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/inotify.h>
+
+#include <misc/nonblocking.h>
+#include <misc/concat_strings.h>
+
+#include <ncd/NCDModule.h>
+
+#include <generated/blog_channel_ncd_sys_watch_directory.h>
+
+#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)
+
+#define MAX_EVENTS 128
+
+struct instance {
+    NCDModuleInst *i;
+    char *dir;
+    int inotify_fd;
+    BFileDescriptor bfd;
+    int processing;
+    struct inotify_event events[MAX_EVENTS];
+    int events_count;
+    int events_index;
+};
+
+struct nextevent_instance {
+    NCDModuleInst *i;
+};
+
+static void assert_event (struct instance *o)
+{
+    ASSERT(o->events_index < o->events_count)
+    ASSERT(o->events[o->events_index].len % sizeof(o->events[0]) == 0)
+    ASSERT(o->events[o->events_index].len / sizeof(o->events[0]) <= o->events_count - (o->events_index + 1))
+}
+
+static int check_event (struct instance *o)
+{
+    assert_event(o);
+    
+    return (
+        strlen(o->events[o->events_index].name) > 0 &&
+        (o->events[o->events_index].mask & (IN_CREATE | IN_DELETE | IN_MODIFY | IN_MOVED_FROM | IN_MOVED_TO))
+    );
+}
+
+static void next_event (struct instance *o)
+{
+    assert_event(o);
+    
+    o->events_index += 1 + o->events[o->events_index].len / sizeof(o->events[0]);
+}
+
+static void skip_bad_events (struct instance *o)
+{
+    while (o->events_index < o->events_count && !check_event(o)) {
+        ModuleLog(o->i, BLOG_ERROR, "unknown inotify event");
+        next_event(o);
+    }
+}
+
+static void inotify_fd_handler (struct instance *o, int events)
+{
+    ASSERT(!o->processing)
+    
+    int res = read(o->inotify_fd, o->events, sizeof(o->events));
+    if (res < 0) {
+        ModuleLog(o->i, BLOG_ERROR, "read failed");
+        return;
+    }
+    
+    ASSERT(res <= sizeof(o->events))
+    ASSERT(res % sizeof(o->events[0]) == 0)
+    
+    // setup buffer state
+    o->events_count = res / sizeof(o->events[0]);
+    o->events_index = 0;
+    
+    // skip bad events
+    skip_bad_events(o);
+    
+    if (o->events_index == o->events_count) {
+        // keep reading
+        return;
+    }
+    
+    // stop reading
+    BReactor_SetFileDescriptorEvents(o->i->reactor, &o->bfd, 0);
+    
+    // set processing
+    o->processing = 1;
+    
+    // signal up
+    NCDModuleInst_Backend_Event(o->i, NCDMODULE_EVENT_UP);
+}
+
+static void inotify_nextevent (struct instance *o)
+{
+    ASSERT(o->processing)
+    assert_event(o);
+    
+    // update index, skip bad events
+    next_event(o);
+    skip_bad_events(o);
+    
+    if (o->events_index == o->events_count) {
+        // start reading
+        BReactor_SetFileDescriptorEvents(o->i->reactor, &o->bfd, BREACTOR_READ);
+        
+        // set not processing
+        o->processing = 0;
+        
+        // signal down
+        NCDModuleInst_Backend_Event(o->i, NCDMODULE_EVENT_DOWN);
+        
+        return;
+    }
+    
+    // signal down and up to process the next event
+    NCDModuleInst_Backend_Event(o->i, NCDMODULE_EVENT_DOWN);
+    NCDModuleInst_Backend_Event(o->i, NCDMODULE_EVENT_UP);
+}
+
+static void func_new (NCDModuleInst *i)
+{
+    // allocate instance
+    struct instance *o = malloc(sizeof(*o));
+    if (!o) {
+        ModuleLog(i, BLOG_ERROR, "failed to allocate instance");
+        goto fail0;
+    }
+    NCDModuleInst_Backend_SetUser(i, o);
+    
+    // init arguments
+    o->i = i;
+    
+    // check arguments
+    NCDValue *dir_arg;
+    if (!NCDValue_ListRead(o->i->args, 1, &dir_arg)) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong arity");
+        goto fail1;
+    }
+    if (NCDValue_Type(dir_arg) != NCDVALUE_STRING) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong type");
+        goto fail1;
+    }
+    o->dir = NCDValue_StringValue(dir_arg);
+    
+    // open inotify
+    if ((o->inotify_fd = inotify_init()) < 0) {
+        ModuleLog(o->i, BLOG_ERROR, "inotify_init failed");
+        goto fail1;
+    }
+    
+    // add watch
+    if (inotify_add_watch(o->inotify_fd, o->dir, IN_CREATE | IN_DELETE | IN_MODIFY | IN_MOVED_FROM | IN_MOVED_TO) < 0) {
+        ModuleLog(o->i, BLOG_ERROR, "inotify_add_watch failed");
+        goto fail2;
+    }
+    
+    // set non-blocking
+    if (!badvpn_set_nonblocking(o->inotify_fd)) {
+        ModuleLog(o->i, BLOG_ERROR, "badvpn_set_nonblocking failed");
+        goto fail2;
+    }
+    
+    // init BFileDescriptor
+    BFileDescriptor_Init(&o->bfd, o->inotify_fd, (BFileDescriptor_handler)inotify_fd_handler, o);
+    if (!BReactor_AddFileDescriptor(o->i->reactor, &o->bfd)) {
+        ModuleLog(o->i, BLOG_ERROR, "BReactor_AddFileDescriptor failed");
+        goto fail2;
+    }
+    BReactor_SetFileDescriptorEvents(o->i->reactor, &o->bfd, BREACTOR_READ);
+    
+    // set not processing
+    o->processing = 0;
+    
+    return;
+    
+fail2:
+    ASSERT_FORCE(close(o->inotify_fd) == 0)
+fail1:
+    free(o);
+fail0:
+    NCDModuleInst_Backend_SetError(i);
+    NCDModuleInst_Backend_Event(i, NCDMODULE_EVENT_DEAD);
+}
+
+static void func_die (void *vo)
+{
+    struct instance *o = vo;
+    NCDModuleInst *i = o->i;
+    
+    // free BFileDescriptor
+    BReactor_RemoveFileDescriptor(o->i->reactor, &o->bfd);
+    
+    // close inotify
+    ASSERT_FORCE(close(o->inotify_fd) == 0)
+    
+    // free instance
+    free(o);
+    
+    NCDModuleInst_Backend_Event(i, NCDMODULE_EVENT_DEAD);
+}
+
+static int func_getvar (void *vo, const char *name, NCDValue *out)
+{
+    struct instance *o = vo;
+    ASSERT(o->processing)
+    assert_event(o);
+    ASSERT(check_event(o))
+    
+    struct inotify_event *event = &o->events[o->events_index];
+    
+    if (!strcmp(name, "event_type")) {
+        const char *str;
+        
+        if ((event->mask & (IN_CREATE | IN_MOVED_TO))) {
+            str = "added";
+        }
+        else if ((event->mask & (IN_DELETE | IN_MOVED_FROM))) {
+            str = "removed";
+        }
+        else if ((event->mask & IN_MODIFY)) {
+            str = "changed";
+        } else {
+            ASSERT(0);
+        }
+        
+        if (!NCDValue_InitString(out, str)) {
+            ModuleLog(o->i, BLOG_ERROR, "NCDValue_InitString failed");
+            return 0;
+        }
+        
+        return 1;
+    }
+    
+    if (!strcmp(name, "filename")) {
+        if (!NCDValue_InitString(out, event->name)) {
+            ModuleLog(o->i, BLOG_ERROR, "NCDValue_InitString failed");
+            return 0;
+        }
+        
+        return 1;
+    }
+    
+    if (!strcmp(name, "filepath")) {
+        char *str = concat_strings(3, o->dir, "/", event->name);
+        if (!str) {
+            ModuleLog(o->i, BLOG_ERROR, "concat_strings failed");
+            return 0;
+        }
+        
+        if (!NCDValue_InitString(out, str)) {
+            ModuleLog(o->i, BLOG_ERROR, "NCDValue_InitString failed");
+            free(str);
+            return 0;
+        }
+        
+        free(str);
+        
+        return 1;
+    }
+    
+    return 0;
+}
+
+static void nextevent_func_new (NCDModuleInst *i)
+{
+    // allocate instance
+    struct nextevent_instance *o = malloc(sizeof(*o));
+    if (!o) {
+        ModuleLog(i, BLOG_ERROR, "failed to allocate instance");
+        goto fail0;
+    }
+    NCDModuleInst_Backend_SetUser(i, o);
+    
+    // init arguments
+    o->i = i;
+    
+    // check arguments
+    if (!NCDValue_ListRead(o->i->args, 0)) {
+        ModuleLog(o->i, BLOG_ERROR, "wrong arity");
+        goto fail1;
+    }
+    
+    // get method object
+    struct instance *mo = i->method_object->inst_user;
+    ASSERT(mo->processing)
+    
+    // signal up.
+    // Do it before finishing the event so our process does not advance any further if
+    // we would be killed the event provider going down.
+    NCDModuleInst_Backend_Event(o->i, NCDMODULE_EVENT_UP);
+    
+    // wait for next event
+    inotify_nextevent(mo);
+    
+    return;
+    
+fail1:
+    free(o);
+fail0:
+    NCDModuleInst_Backend_SetError(i);
+    NCDModuleInst_Backend_Event(i, NCDMODULE_EVENT_DEAD);
+}
+
+static void nextevent_func_die (void *vo)
+{
+    struct nextevent_instance *o = vo;
+    NCDModuleInst *i = o->i;
+    
+    // free instance
+    free(o);
+    
+    NCDModuleInst_Backend_Event(i, NCDMODULE_EVENT_DEAD);
+}
+
+static const struct NCDModule modules[] = {
+    {
+        .type = "sys.watch_directory",
+        .func_new = func_new,
+        .func_die = func_die,
+        .func_getvar = func_getvar
+    }, {
+        .type = "sys.watch_directory::nextevent",
+        .func_new = nextevent_func_new,
+        .func_die = nextevent_func_die
+    }, {
+        .type = NULL
+    }
+};
+
+const struct NCDModuleGroup ncdmodule_sys_watch_directory = {
+    .modules = modules
+};