LCOV - code coverage report
Current view: top level - source4/ntvfs/sysdep - inotify.c (source / functions) Hit Total Coverage
Test: coverage report for abartlet/fix-coverage dd10fb34 Lines: 2 144 1.4 %
Date: 2021-09-23 10:06:22 Functions: 1 10 10.0 %

          Line data    Source code
       1             : /* 
       2             :    Unix SMB/CIFS implementation.
       3             : 
       4             :    Copyright (C) Andrew Tridgell 2006
       5             :    
       6             :    This program is free software; you can redistribute it and/or modify
       7             :    it under the terms of the GNU General Public License as published by
       8             :    the Free Software Foundation; either version 3 of the License, or
       9             :    (at your option) any later version.
      10             :    
      11             :    This program is distributed in the hope that it will be useful,
      12             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      13             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14             :    GNU General Public License for more details.
      15             :    
      16             :    You should have received a copy of the GNU General Public License
      17             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      18             : */
      19             : 
      20             : /*
      21             :   notify implementation using inotify
      22             : */
      23             : 
      24             : #include "includes.h"
      25             : #include "system/filesys.h"
      26             : #include <tevent.h>
      27             : #include "ntvfs/sysdep/sys_notify.h"
      28             : #include "../lib/util/dlinklist.h"
      29             : #include "libcli/raw/smb.h"
      30             : #include "param/param.h"
      31             : 
      32             : #include <sys/inotify.h>
      33             : 
      34             : /* glibc < 2.5 headers don't have these defines */
      35             : #ifndef IN_ONLYDIR
      36             : #define IN_ONLYDIR 0x01000000
      37             : #endif
      38             : #ifndef IN_MASK_ADD
      39             : #define IN_MASK_ADD 0x20000000
      40             : #endif
      41             : 
      42             : struct inotify_private {
      43             :         struct sys_notify_context *ctx;
      44             :         int fd;
      45             :         struct inotify_watch_context *watches;
      46             : };
      47             : 
      48             : struct inotify_watch_context {
      49             :         struct inotify_watch_context *next, *prev;
      50             :         struct inotify_private *in;
      51             :         int wd;
      52             :         sys_notify_callback_t callback;
      53             :         void *private_data;
      54             :         uint32_t mask; /* the inotify mask */
      55             :         uint32_t filter; /* the windows completion filter */
      56             :         const char *path;
      57             : };
      58             : 
      59             : 
      60             : /*
      61             :   see if a particular event from inotify really does match a requested
      62             :   notify event in SMB
      63             : */
      64           0 : static bool filter_match(struct inotify_watch_context *w,
      65             :                          struct inotify_event *e)
      66             : {
      67           0 :         if ((e->mask & w->mask) == 0) {
      68             :                 /* this happens because inotify_add_watch() coalesces watches on the same
      69             :                    path, oring their masks together */
      70           0 :                 return false;
      71             :         }
      72             : 
      73             :         /* SMB separates the filters for files and directories */
      74           0 :         if (e->mask & IN_ISDIR) {
      75           0 :                 if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
      76           0 :                         return false;
      77             :                 }
      78             :         } else {
      79           0 :                 if ((e->mask & IN_ATTRIB) &&
      80           0 :                     (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
      81             :                                   FILE_NOTIFY_CHANGE_LAST_WRITE|
      82             :                                   FILE_NOTIFY_CHANGE_LAST_ACCESS|
      83             :                                   FILE_NOTIFY_CHANGE_EA|
      84             :                                   FILE_NOTIFY_CHANGE_SECURITY))) {
      85           0 :                         return true;
      86             :                 }
      87           0 :                 if ((e->mask & IN_MODIFY) && 
      88           0 :                     (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
      89           0 :                         return true;
      90             :                 }
      91           0 :                 if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
      92           0 :                         return false;
      93             :                 }
      94             :         }
      95             : 
      96           0 :         return true;
      97             : }
      98             :         
      99             : 
     100             : 
     101             : /*
     102             :   dispatch one inotify event
     103             :   
     104             :   the cookies are used to correctly handle renames
     105             : */
     106           0 : static void inotify_dispatch(struct inotify_private *in, 
     107             :                              struct inotify_event *e, 
     108             :                              uint32_t prev_cookie,
     109             :                              struct inotify_event *e2)
     110             : {
     111             :         struct inotify_watch_context *w, *next;
     112             :         struct notify_event ne;
     113             : 
     114             :         /* ignore extraneous events, such as unmount and IN_IGNORED events */
     115           0 :         if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
     116             :                         IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
     117           0 :                 return;
     118             :         }
     119             : 
     120             :         /* map the inotify mask to a action. This gets complicated for
     121             :            renames */
     122           0 :         if (e->mask & IN_CREATE) {
     123           0 :                 ne.action = NOTIFY_ACTION_ADDED;
     124           0 :         } else if (e->mask & IN_DELETE) {
     125           0 :                 ne.action = NOTIFY_ACTION_REMOVED;
     126           0 :         } else if (e->mask & IN_MOVED_FROM) {
     127           0 :                 if (e2 != NULL && e2->cookie == e->cookie) {
     128           0 :                         ne.action = NOTIFY_ACTION_OLD_NAME;
     129             :                 } else {
     130           0 :                         ne.action = NOTIFY_ACTION_REMOVED;
     131             :                 }
     132           0 :         } else if (e->mask & IN_MOVED_TO) {
     133           0 :                 if (e->cookie == prev_cookie) {
     134           0 :                         ne.action = NOTIFY_ACTION_NEW_NAME;
     135             :                 } else {
     136           0 :                         ne.action = NOTIFY_ACTION_ADDED;
     137             :                 }
     138             :         } else {
     139           0 :                 ne.action = NOTIFY_ACTION_MODIFIED;
     140             :         }
     141           0 :         ne.path = e->name;
     142             : 
     143             :         /* find any watches that have this watch descriptor */
     144           0 :         for (w=in->watches;w;w=next) {
     145           0 :                 next = w->next;
     146           0 :                 if (w->wd == e->wd && filter_match(w, e)) {
     147           0 :                         ne.dir = w->path;
     148           0 :                         w->callback(in->ctx, w->private_data, &ne);
     149             :                 }
     150             :         }
     151             : 
     152             :         /* SMB expects a file rename to generate three events, two for
     153             :            the rename and the other for a modify of the
     154             :            destination. Strange! */
     155           0 :         if (ne.action != NOTIFY_ACTION_NEW_NAME ||
     156           0 :             (e->mask & IN_ISDIR) != 0) {
     157           0 :                 return;
     158             :         }
     159             : 
     160           0 :         ne.action = NOTIFY_ACTION_MODIFIED;
     161           0 :         e->mask = IN_ATTRIB;
     162             :         
     163           0 :         for (w=in->watches;w;w=next) {
     164           0 :                 next = w->next;
     165           0 :                 if (w->wd == e->wd && filter_match(w, e) &&
     166           0 :                     !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
     167           0 :                         ne.dir = w->path;
     168           0 :                         w->callback(in->ctx, w->private_data, &ne);
     169             :                 }
     170             :         }
     171             : }
     172             : 
     173             : /*
     174             :   called when the kernel has some events for us
     175             : */
     176           0 : static void inotify_handler(struct tevent_context *ev, struct tevent_fd *fde,
     177             :                             uint16_t flags, void *private_data)
     178             : {
     179           0 :         struct inotify_private *in = talloc_get_type(private_data,
     180             :                                                      struct inotify_private);
     181           0 :         int bufsize = 0;
     182             :         struct inotify_event *e0, *e;
     183           0 :         uint32_t prev_cookie=0;
     184             : 
     185             :         /*
     186             :           we must use FIONREAD as we cannot predict the length of the
     187             :           filenames, and thus can't know how much to allocate
     188             :           otherwise
     189             :         */
     190           0 :         if (ioctl(in->fd, FIONREAD, &bufsize) != 0 || 
     191           0 :             bufsize == 0) {
     192           0 :                 DEBUG(0,("No data on inotify fd?!\n"));
     193           0 :                 return;
     194             :         }
     195             : 
     196           0 :         e0 = e = talloc_size(in, bufsize);
     197           0 :         if (e == NULL) return;
     198             : 
     199           0 :         if (read(in->fd, e0, bufsize) != bufsize) {
     200           0 :                 DEBUG(0,("Failed to read all inotify data\n"));
     201           0 :                 talloc_free(e0);
     202           0 :                 return;
     203             :         }
     204             : 
     205             :         /* we can get more than one event in the buffer */
     206           0 :         while (bufsize >= sizeof(*e)) {
     207           0 :                 struct inotify_event *e2 = NULL;
     208           0 :                 bufsize -= e->len + sizeof(*e);
     209           0 :                 if (bufsize >= sizeof(*e)) {
     210           0 :                         e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
     211             :                 }
     212           0 :                 inotify_dispatch(in, e, prev_cookie, e2);
     213           0 :                 prev_cookie = e->cookie;
     214           0 :                 e = e2;
     215             :         }
     216             : 
     217           0 :         talloc_free(e0);
     218             : }
     219             : 
     220             : /*
     221             :   setup the inotify handle - called the first time a watch is added on
     222             :   this context
     223             : */
     224           0 : static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
     225             : {
     226             :         struct inotify_private *in;
     227             :         struct tevent_fd *fde;
     228             : 
     229           0 :         in = talloc(ctx, struct inotify_private);
     230           0 :         NT_STATUS_HAVE_NO_MEMORY(in);
     231             : 
     232           0 :         in->fd = inotify_init();
     233           0 :         if (in->fd == -1) {
     234           0 :                 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
     235           0 :                 talloc_free(in);
     236           0 :                 return map_nt_error_from_unix_common(errno);
     237             :         }
     238           0 :         in->ctx = ctx;
     239           0 :         in->watches = NULL;
     240             : 
     241           0 :         ctx->private_data = in;
     242             : 
     243             :         /* add a event waiting for the inotify fd to be readable */
     244           0 :         fde = tevent_add_fd(ctx->ev, in, in->fd,
     245             :                            TEVENT_FD_READ, inotify_handler, in);
     246           0 :         if (!fde) {
     247           0 :                 if (errno == 0) {
     248           0 :                         errno = ENOMEM;
     249             :                 }
     250           0 :                 DEBUG(0,("Failed to tevent_add_fd() - %s\n", strerror(errno)));
     251           0 :                 talloc_free(in);
     252           0 :                 return map_nt_error_from_unix_common(errno);
     253             :         }
     254             : 
     255           0 :         tevent_fd_set_auto_close(fde);
     256             : 
     257           0 :         return NT_STATUS_OK;
     258             : }
     259             : 
     260             : 
     261             : /*
     262             :   map from a change notify mask to a inotify mask. Remove any bits
     263             :   which we can handle
     264             : */
     265             : static const struct {
     266             :         uint32_t notify_mask;
     267             :         uint32_t inotify_mask;
     268             : } inotify_mapping[] = {
     269             :         {FILE_NOTIFY_CHANGE_FILE_NAME,   IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
     270             :         {FILE_NOTIFY_CHANGE_DIR_NAME,    IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
     271             :         {FILE_NOTIFY_CHANGE_ATTRIBUTES,  IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
     272             :         {FILE_NOTIFY_CHANGE_LAST_WRITE,  IN_ATTRIB},
     273             :         {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
     274             :         {FILE_NOTIFY_CHANGE_EA,          IN_ATTRIB},
     275             :         {FILE_NOTIFY_CHANGE_SECURITY,    IN_ATTRIB}
     276             : };
     277             : 
     278           0 : static uint32_t inotify_map(struct notify_entry *e)
     279             : {
     280             :         int i;
     281           0 :         uint32_t out=0;
     282           0 :         for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
     283           0 :                 if (inotify_mapping[i].notify_mask & e->filter) {
     284           0 :                         out |= inotify_mapping[i].inotify_mask;
     285           0 :                         e->filter &= ~inotify_mapping[i].notify_mask;
     286             :                 }
     287             :         }
     288           0 :         return out;
     289             : }
     290             : 
     291             : /*
     292             :   destroy a watch
     293             : */
     294           0 : static int watch_destructor(struct inotify_watch_context *w)
     295             : {
     296           0 :         struct inotify_private *in = w->in;
     297           0 :         int wd = w->wd;
     298           0 :         DLIST_REMOVE(w->in->watches, w);
     299             : 
     300             :         /* only rm the watch if its the last one with this wd */
     301           0 :         for (w=in->watches;w;w=w->next) {
     302           0 :                 if (w->wd == wd) break;
     303             :         }
     304           0 :         if (w == NULL) {
     305           0 :                 inotify_rm_watch(in->fd, wd);
     306             :         }
     307           0 :         return 0;
     308             : }
     309             : 
     310             : 
     311             : /*
     312             :   add a watch. The watch is removed when the caller calls
     313             :   talloc_free() on *handle
     314             : */
     315           0 : static NTSTATUS inotify_watch(struct sys_notify_context *ctx,
     316             :                               struct notify_entry *e,
     317             :                               sys_notify_callback_t callback,
     318             :                               void *private_data, 
     319             :                               void *handle_p)
     320             : {
     321             :         struct inotify_private *in;
     322             :         int wd;
     323             :         uint32_t mask;
     324             :         struct inotify_watch_context *w;
     325           0 :         uint32_t filter = e->filter;
     326           0 :         void **handle = (void **)handle_p;
     327             : 
     328             :         /* maybe setup the inotify fd */
     329           0 :         if (ctx->private_data == NULL) {
     330             :                 NTSTATUS status;
     331           0 :                 status = inotify_setup(ctx);
     332           0 :                 NT_STATUS_NOT_OK_RETURN(status);
     333             :         }
     334             : 
     335           0 :         in = talloc_get_type(ctx->private_data, struct inotify_private);
     336             : 
     337           0 :         mask = inotify_map(e);
     338           0 :         if (mask == 0) {
     339             :                 /* this filter can't be handled by inotify */
     340           0 :                 return NT_STATUS_INVALID_PARAMETER;
     341             :         }
     342             : 
     343             :         /* using IN_MASK_ADD allows us to cope with inotify() returning the same
     344             :            watch descriptor for muliple watches on the same path */
     345           0 :         mask |= (IN_MASK_ADD | IN_ONLYDIR);
     346             : 
     347             :         /* get a new watch descriptor for this path */
     348           0 :         wd = inotify_add_watch(in->fd, e->path, mask);
     349           0 :         if (wd == -1) {
     350           0 :                 e->filter = filter;
     351           0 :                 return map_nt_error_from_unix_common(errno);
     352             :         }
     353             : 
     354           0 :         w = talloc(in, struct inotify_watch_context);
     355           0 :         if (w == NULL) {
     356           0 :                 inotify_rm_watch(in->fd, wd);
     357           0 :                 e->filter = filter;
     358           0 :                 return NT_STATUS_NO_MEMORY;
     359             :         }
     360             : 
     361           0 :         w->in = in;
     362           0 :         w->wd = wd;
     363           0 :         w->callback = callback;
     364           0 :         w->private_data = private_data;
     365           0 :         w->mask = mask;
     366           0 :         w->filter = filter;
     367           0 :         w->path = talloc_strdup(w, e->path);
     368           0 :         if (w->path == NULL) {
     369           0 :                 inotify_rm_watch(in->fd, wd);
     370           0 :                 e->filter = filter;
     371           0 :                 return NT_STATUS_NO_MEMORY;
     372             :         }
     373             : 
     374           0 :         (*handle) = w;
     375             : 
     376           0 :         DLIST_ADD(in->watches, w);
     377             : 
     378             :         /* the caller frees the handle to stop watching */
     379           0 :         talloc_set_destructor(w, watch_destructor);
     380             :         
     381           0 :         return NT_STATUS_OK;
     382             : }
     383             : 
     384             : 
     385             : static struct sys_notify_backend inotify = {
     386             :         .name = "inotify",
     387             :         .notify_watch = inotify_watch
     388             : };
     389             : 
     390             : /*
     391             :   initialialise the inotify module
     392             :  */
     393             : NTSTATUS sys_notify_inotify_init(TALLOC_CTX *);
     394          66 : NTSTATUS sys_notify_inotify_init(TALLOC_CTX *ctx)
     395             : {
     396             :         /* register ourselves as a system inotify module */
     397          66 :         return sys_notify_register(ctx, &inotify);
     398             : }

Generated by: LCOV version 1.13