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| author | Amir Goldstein <amir73il@gmail.com> | 2020-04-20 21:42:59 +0300 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2020-04-20 21:22:09 +0200 |
| commit | a93e5c9593a95d09a1c9deb94dfdecbb970b8162 (patch) | |
| tree | 1f75f40894a36442649bc770c430e0fd81bbc9f8 /man7 | |
| parent | 4e5351855283d068ccc0324c410f7b7466f71f40 (diff) | |
| download | man-pages-a93e5c9593a95d09a1c9deb94dfdecbb970b8162.tar.gz | |
fanotify.7, fanotify_mark.2: Document FAN_DIR_MODIFY
Document the details of the new FAN_DIR_MODIFY event, which
introduces entry name information to the fanotify event
reporting format.
Enhance the fanotify_fid.c example to also report this event.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Diffstat (limited to 'man7')
| -rw-r--r-- | man7/fanotify.7 | 71 |
1 files changed, 61 insertions, 10 deletions
diff --git a/man7/fanotify.7 b/man7/fanotify.7 index 72e7e4fb9f..cd258abf4b 100644 --- a/man7/fanotify.7 +++ b/man7/fanotify.7 @@ -324,6 +324,9 @@ A watched file or directory was moved. .B FAN_MODIFY A file was modified. .TP +.B FAN_DIR_MODIFY +A directory entry was created, deleted or moved. +.TP .B FAN_CLOSE_WRITE A file that was opened for writing .RB ( O_WRONLY @@ -395,9 +398,11 @@ For example, when an fanotify file descriptor is created using the .I info_type field of this header is set to -.BR FAN_EVENT_INFO_TYPE_FID . -Event listeners can use this field to check that the additional -information received for an event is of the correct type. +.BR FAN_EVENT_INFO_TYPE_FID +or +.BR FAN_EVENT_INFO_TYPE_DFID_NAME . +Event listeners can use this field to check what additional information +is received for an event. Additionally, the .I fanotify_event_info_header also contains a @@ -443,6 +448,14 @@ and will carry the .IR file_handle information for the child object if the child object is being watched. +For the event +.BR FAN_DIR_MODIFY , +the +.I info_type +field of this header is set to +.BR FAN_EVENT_INFO_TYPE_DFID_NAME . +The file handle describes the modified directory and a null terminated +name of the modified entry follows directly after the file handle buffer. .PP The following macros are provided to iterate over a buffer containing fanotify event metadata returned by a @@ -627,9 +640,11 @@ events for the monitored directory itself. Fanotify monitoring of directories is not recursive: to monitor subdirectories under a directory, additional marks must be created. -(But note that the fanotify API provides no way of detecting when a -subdirectory has been created under a marked directory, -which makes recursive monitoring difficult.) +The +.B FAN_DIR_MODIFY +event can be used for detecting when a subdirectory has been created under +a marked directory. +An additional mark must then be set on the newly created subdirectory. Monitoring mounts offers the capability to monitor a whole directory tree. Monitoring filesystems offers the capability to monitor changes made from any mount of a filesystem instance. @@ -923,6 +938,8 @@ The program marks the filesystem object that is passed as a command-line argument and waits until an event of type .B FAN_CREATE +or +.B FAN_DIR_MODIFY has occurred. The event mask indicates which type of filesystem object\(emeither a file or a directory\(emwas created. @@ -939,7 +956,9 @@ This is followed by the creation of a regular file, This results in a .B FAN_CREATE event being generated and reported against the file's parent watched -directory object. +directory object and a +.B FAN_DIR_MODIFY +event being generated and reported with the created file name. Program execution ends once all events captured within the buffer have been processed. .PP @@ -949,6 +968,9 @@ been processed. Listening for events. FAN_CREATE (file created): Directory /home/user has been modified. +FAN_DIR_MODIFY (entry changed): + Directory /home/user has been modified. + Entry 'testfile.txt' is not a subdirectory. All events processed successfully. Program exiting. $ \fBtouch /home/user/testfile.txt\fP # In another terminal @@ -963,7 +985,9 @@ This specific action results in a .B FAN_CREATE event being generated and is reported with the .B FAN_ONDIR -flag set. +flag set and a +.B FAN_DIR_MODIFY +event being generated and reported with the created directory name. .PP .in +4n .EX @@ -971,6 +995,9 @@ flag set. Listening for events. FAN_CREATE | FAN_ONDIR (subdirectory created): Directory /home/user has been modified. +FAN_DIR_MODIFY (entry changed): + Directory /home/user has been modified. + Entry 'testdir' is a subdirectory. All events processed successfully. Program exiting. $ \fBmkdir \-p /home/user/testdir\fP # In another terminal @@ -1003,6 +1030,8 @@ main(int argc, char **argv) struct file_handle *file_handle; struct fanotify_event_metadata *metadata; struct fanotify_event_info_fid *fid; + const char *file_name; + struct stat sb; if (argc != 2) { fprintf(stderr, "Invalid number of command line arguments.\en"); @@ -1028,7 +1057,7 @@ main(int argc, char **argv) /* Place a mark on the filesystem object supplied in argv[1]. */ ret = fanotify_mark(fd, FAN_MARK_ADD | FAN_MARK_ONLYDIR, - FAN_CREATE | FAN_ONDIR, + FAN_DIR_MODIFY | FAN_CREATE | FAN_ONDIR, AT_FDCWD, argv[1]); if (ret == \-1) { perror("fanotify_mark"); @@ -1055,11 +1084,18 @@ main(int argc, char **argv) /* Ensure that the event info is of the correct type */ - if (fid\->hdr.info_type != FAN_EVENT_INFO_TYPE_FID) { + if (fid\->hdr.info_type == FAN_EVENT_INFO_TYPE_FID) { + file_name = NULL; + } else if (fid\->hdr.info_type == FAN_EVENT_INFO_TYPE_DFID_NAME) { + file_name = file_handle->f_handle + file_handle->handle_bytes; + } else { fprintf(stderr, "Received unexpected event info type.\en"); exit(EXIT_FAILURE); } + if (metadata\->mask == FAN_DIR_MODIFY) + printf("FAN_DIR_MODIFY (entry changed):\en"); + if (metadata\->mask == FAN_CREATE) printf("FAN_CREATE (file created):\en"); @@ -1100,6 +1136,21 @@ main(int argc, char **argv) path[path_len] = \(aq\e0\(aq; printf("\etDirectory \(aq%s\(aq has been modified.\en", path); + if (file_name) { + ret = fstatat(event_fd, file_name, &sb, 0); + if (ret == \-1) { + if (errno != ENOENT) { + perror("fstatat"); + exit(EXIT_FAILURE); + } + printf("\etEntry %\(aqs\(aq does not exist.\en", file_name); + } else if ((sb.st_mode & S_IFMT) == S_IFDIR) { + printf("\etEntry \(aq%s\(aq is a subdirectory.\en", file_name); + } else { + printf("\etEntry \(aq%s\(aq is not a subdirectory.\en", file_name); + } + } + /* Close associated file descriptor for this event */ close(event_fd); |