/* Unix SMB/CIFS implementation. Copyright (C) Andrew Tridgell 2006 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program 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, see <http://www.gnu.org/licenses/>. */ /* notify implementation using inotify */ #include "includes.h" #include "../librpc/gen_ndr/notify.h" #include "smbd/smbd.h" #ifdef HAVE_INOTIFY #include <sys/inotify.h> /* glibc < 2.5 headers don't have these defines */ #ifndef IN_ONLYDIR #define IN_ONLYDIR 0x01000000 #endif #ifndef IN_MASK_ADD #define IN_MASK_ADD 0x20000000 #endif struct inotify_private { struct sys_notify_context *ctx; int fd; struct inotify_watch_context *watches; }; struct inotify_watch_context { struct inotify_watch_context *next, *prev; struct inotify_private *in; int wd; void (*callback)(struct sys_notify_context *ctx, void *private_data, struct notify_event *ev); void *private_data; uint32_t mask; /* the inotify mask */ uint32_t filter; /* the windows completion filter */ const char *path; }; /* destroy the inotify private context */ static int inotify_destructor(struct inotify_private *in) { close(in->fd); return 0; } /* see if a particular event from inotify really does match a requested notify event in SMB */ static bool filter_match(struct inotify_watch_context *w, struct inotify_event *e) { DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n", e->mask, w->mask, w->filter)); if ((e->mask & w->mask) == 0) { /* this happens because inotify_add_watch() coalesces watches on the same path, oring their masks together */ return False; } /* SMB separates the filters for files and directories */ if (e->mask & IN_ISDIR) { if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) { return False; } } else { if ((e->mask & IN_ATTRIB) && (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES| FILE_NOTIFY_CHANGE_LAST_WRITE| FILE_NOTIFY_CHANGE_LAST_ACCESS| FILE_NOTIFY_CHANGE_EA| FILE_NOTIFY_CHANGE_SECURITY))) { return True; } if ((e->mask & IN_MODIFY) && (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) { return True; } if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) { return False; } } return True; } /* dispatch one inotify event the cookies are used to correctly handle renames */ static void inotify_dispatch(struct inotify_private *in, struct inotify_event *e, uint32_t prev_cookie, struct inotify_event *e2) { struct inotify_watch_context *w, *next; struct notify_event ne; DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n", e->mask, e->len ? e->name : "")); /* ignore extraneous events, such as unmount and IN_IGNORED events */ if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE| IN_MOVED_FROM|IN_MOVED_TO)) == 0) { return; } /* map the inotify mask to a action. This gets complicated for renames */ if (e->mask & IN_CREATE) { ne.action = NOTIFY_ACTION_ADDED; } else if (e->mask & IN_DELETE) { ne.action = NOTIFY_ACTION_REMOVED; } else if (e->mask & IN_MOVED_FROM) { if (e2 != NULL && e2->cookie == e->cookie) { ne.action = NOTIFY_ACTION_OLD_NAME; } else { ne.action = NOTIFY_ACTION_REMOVED; } } else if (e->mask & IN_MOVED_TO) { if (e->cookie == prev_cookie) { ne.action = NOTIFY_ACTION_NEW_NAME; } else { ne.action = NOTIFY_ACTION_ADDED; } } else { ne.action = NOTIFY_ACTION_MODIFIED; } ne.path = e->name; DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n", ne.action, ne.path)); /* find any watches that have this watch descriptor */ for (w=in->watches;w;w=next) { next = w->next; if (w->wd == e->wd && filter_match(w, e)) { w->callback(in->ctx, w->private_data, &ne); } } /* SMB expects a file rename to generate three events, two for the rename and the other for a modify of the destination. Strange! */ if (ne.action != NOTIFY_ACTION_NEW_NAME || (e->mask & IN_ISDIR) != 0) { return; } ne.action = NOTIFY_ACTION_MODIFIED; e->mask = IN_ATTRIB; for (w=in->watches;w;w=next) { next = w->next; if (w->wd == e->wd && filter_match(w, e) && !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) { w->callback(in->ctx, w->private_data, &ne); } } } /* called when the kernel has some events for us */ static void inotify_handler(struct event_context *ev, struct fd_event *fde, uint16_t flags, void *private_data) { struct inotify_private *in = talloc_get_type(private_data, struct inotify_private); int bufsize = 0; struct inotify_event *e0, *e; uint32_t prev_cookie=0; NTSTATUS status; /* we must use FIONREAD as we cannot predict the length of the filenames, and thus can't know how much to allocate otherwise */ if (ioctl(in->fd, FIONREAD, &bufsize) != 0 || bufsize == 0) { DEBUG(0,("No data on inotify fd?!\n")); TALLOC_FREE(fde); return; } e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize + 1); if (e == NULL) return; ((uint8_t *)e)[bufsize] = '\0'; status = read_data(in->fd, (char *)e0, bufsize); if (!NT_STATUS_IS_OK(status)) { DEBUG(0,("Failed to read all inotify data - %s\n", nt_errstr(status))); talloc_free(e0); /* the inotify fd will now be out of sync, * can't keep reading data off it */ TALLOC_FREE(fde); return; } /* we can get more than one event in the buffer */ while (e && (bufsize >= sizeof(*e))) { struct inotify_event *e2 = NULL; bufsize -= e->len + sizeof(*e); if (bufsize >= sizeof(*e)) { e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e); } inotify_dispatch(in, e, prev_cookie, e2); prev_cookie = e->cookie; e = e2; } talloc_free(e0); } /* setup the inotify handle - called the first time a watch is added on this context */ static NTSTATUS inotify_setup(struct sys_notify_context *ctx) { struct inotify_private *in; if (!lp_parm_bool(-1, "notify", "inotify", True)) { return NT_STATUS_INVALID_SYSTEM_SERVICE; } in = talloc(ctx, struct inotify_private); NT_STATUS_HAVE_NO_MEMORY(in); in->fd = inotify_init(); if (in->fd == -1) { DEBUG(0,("Failed to init inotify - %s\n", strerror(errno))); talloc_free(in); return map_nt_error_from_unix(errno); } in->ctx = ctx; in->watches = NULL; ctx->private_data = in; talloc_set_destructor(in, inotify_destructor); /* add a event waiting for the inotify fd to be readable */ event_add_fd(ctx->ev, in, in->fd, EVENT_FD_READ, inotify_handler, in); return NT_STATUS_OK; } /* map from a change notify mask to a inotify mask. Remove any bits which we can handle */ static const struct { uint32_t notify_mask; uint32_t inotify_mask; } inotify_mapping[] = { {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO}, {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO}, {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY}, {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB}, {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB}, {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB}, {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB} }; static uint32_t inotify_map(uint32_t *filter) { int i; uint32_t out=0; for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) { if (inotify_mapping[i].notify_mask & *filter) { out |= inotify_mapping[i].inotify_mask; *filter &= ~inotify_mapping[i].notify_mask; } } return out; } /* destroy a watch */ static int watch_destructor(struct inotify_watch_context *w) { struct inotify_private *in = w->in; int wd = w->wd; DLIST_REMOVE(w->in->watches, w); /* only rm the watch if its the last one with this wd */ for (w=in->watches;w;w=w->next) { if (w->wd == wd) break; } if (w == NULL) { DEBUG(10, ("Deleting inotify watch %d\n", wd)); if (inotify_rm_watch(in->fd, wd) == -1) { DEBUG(1, ("inotify_rm_watch returned %s\n", strerror(errno))); } } return 0; } /* add a watch. The watch is removed when the caller calls talloc_free() on *handle */ NTSTATUS inotify_watch(struct sys_notify_context *ctx, const char *path, uint32_t *filter, uint32_t *subdir_filter, void (*callback)(struct sys_notify_context *ctx, void *private_data, struct notify_event *ev), void *private_data, void *handle_p) { struct inotify_private *in; int wd; uint32_t mask; struct inotify_watch_context *w; uint32_t orig_filter = *filter; void **handle = (void **)handle_p; /* maybe setup the inotify fd */ if (ctx->private_data == NULL) { NTSTATUS status; status = inotify_setup(ctx); NT_STATUS_NOT_OK_RETURN(status); } in = talloc_get_type(ctx->private_data, struct inotify_private); mask = inotify_map(filter); if (mask == 0) { /* this filter can't be handled by inotify */ return NT_STATUS_INVALID_PARAMETER; } /* using IN_MASK_ADD allows us to cope with inotify() returning the same watch descriptor for multiple watches on the same path */ mask |= (IN_MASK_ADD | IN_ONLYDIR); /* get a new watch descriptor for this path */ wd = inotify_add_watch(in->fd, path, mask); if (wd == -1) { *filter = orig_filter; DEBUG(1, ("inotify_add_watch returned %s\n", strerror(errno))); return map_nt_error_from_unix(errno); } DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n", path, mask, wd)); w = talloc(in, struct inotify_watch_context); if (w == NULL) { inotify_rm_watch(in->fd, wd); *filter = orig_filter; return NT_STATUS_NO_MEMORY; } w->in = in; w->wd = wd; w->callback = callback; w->private_data = private_data; w->mask = mask; w->filter = orig_filter; w->path = talloc_strdup(w, path); if (w->path == NULL) { inotify_rm_watch(in->fd, wd); *filter = orig_filter; return NT_STATUS_NO_MEMORY; } (*handle) = w; DLIST_ADD(in->watches, w); /* the caller frees the handle to stop watching */ talloc_set_destructor(w, watch_destructor); return NT_STATUS_OK; } #endif