1LSLK(8) System Manager's Manual LSLK(8)
2
6 !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!!!
7 ! !
8 ! Revision 1.29 represents the end of life for lslk. I don't have time !
9 ! to support it. Please don't report bugs to me. I will politely !
10 ! decline to work on them. !
11 ! !
12 ! Vic Abell <abe@purdue.edu>, July 11, 2001 !
13 ! !
14 !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!! !!!NOTICE!!!!
15
17 lslk - list local locks
18
20 lslk [ -abhnOvw ] [ -i i ] [ -k k ] [ -p p ] [ -S [t] ] [ paths ]
21
23 Lslk revision 1.29 lists information about locks held on files with
24 local inodes on systems running the following UNIX dialects:
25 AIX 3.2.5, 4.1.4, 4.2[.1], and AIX 4.3[.[12]]
27 DEC OSF/1, Digital UNIX, and Tru64 UNIX [2345].[01] and 3.2
28 Linux
29 SCO OpenDesktop or OpenServer 3.0 and 5.0.[0245]
30 Sequent PTX 2.1.9, 4.2.1, 4.3, and 4.4
31 Solaris 2.[345], 2.5.1, 2.6, 7, and 8 (excluding Veritas
32 VxFS local files)
33 SunOS 4.1.3
34 The lock may belong to a process on the local system or to a process on
36 an NFS client system to which the local system is an NFS server.
37 Notes: Linux and PTX 2.1.9 lslk don't report on locks held by NFS
38 clients; Solaris lslk won't report locks held on local Veritas VxFS
39 files.
40
42 In the absence of any options, lslk lists all locks associated with the
43 local files of the system.
44 When selection options are specified, the listing of all locks is dis‐
46 abled, and the selection options are ORed together. Only locks meeting
47 any selection criterion are listed.
48 When the -a option is specified, the listing of all locks is disabled,
50 and the selection options are ANDed together. Only locks that meet all
51 selection criteria are listed.
52 -a This option causes list selection options to be ANDed, as
54 described above.
55 -b This option causes lslk to avoid kernel functions that might
57 block - lstat(2), readlink(2), and stat(2).
58 See the BLOCKS AND TIMEOUTS and AVOIDING KERNEL BLOCKS sec‐
60 tions for information on using this option.
61 -i i This option selects the listing of locks whose owning process
63 is on the Internet host whose name or network address is i.
64 Multiple addresses may be declared with multiple -i i options.
66 -k k This option specifies k as an alternate to the default kernel
68 name list file path. The default kernel name list file path
69 is listed in the -h help output.
70 It may be necessary to specify an alternate kernel name list
72 path when the file at the default path isn't the booted kernel
73 -- e.g., the default is /vmunix, but the booted kernel file is
74 /vmunix.new.
75 Unless lslk accesses the correct kernel name list file, it may
77 derive incorrect addresses for symbols in kernel memory, caus‐
78 ing it to fail.
79 -n This option inhibits the conversion of network host names to
81 network addresses and the conversion of network addresses to
82 network host names.
83 This option may be useful when the host name to address trans‐
85 lation service (e.g., the Domain Name Server) is slow or inop‐
86 erative.
87 If you use this option on hosts whose kernel lock table con‐
89 tains only host names - e.g., SCO or Solaris - or you use this
90 option and also select the listing of locks by an Internet
91 network address with the -i i option, lslk will not be able to
92 locate any locks with the specified network address, nor will
93 it be able to report network addresses in its output. The -n
94 option inhibits the necessary conversion of kernel lock table
95 host names to network addresses.
96 -O This option directs lslk to bypass the strategy it uses to
98 avoid being blocked by some kernel operations - i.e., doing
99 them in forked child processes. See the BLOCKS AND TIMEOUTS
100 and AVOIDING KERNEL BLOCKS sections for more information on
101 kernel operations that may block lslk.
102 -p p This option selects the listing of locks whose owning process
104 IDentification (PID) numbers are in the comma-separated list,
105 p.
106 -S [t] This option specifies an optional time-out seconds value for
108 kernel functions - lstat(2), readlink(2), and stat(2) - that
109 might otherwise deadlock. The minimum for t is two; the
110 default, fifteen; when no value is specified, the default is
111 used.
112 See the BLOCKS AND TIMEOUTS section for more information.
114 -v When this option is specified, lslk lists version information
116 - i.e., where, when and how it was constructed.
117 -w This option suppresses non-fatal warning messages.
119 paths This option specifies a list of file path names for which lslk
121 is to list lock information.
122
124 Lslk lists the information for each lock on a separate line in the fol‐
125 lowing columns. (The columns are dynamically sized.)
126 SRC indicates the source of the process holding the lock.
128 If the source is a local process, its command name is dis‐
130 played, or ``(unknown)'' if the command name can't be deter‐
131 mined.
132 If the source is a remote process, the host name or network
134 number where the remote process executes is displayed.
135 PID is the Process IDentification number of the process holding the
137 lock.
138 DEV is the device (major and minor numbers) on which the locked
140 file resides.
141 INUM is the inode number of the locked file.
143 SZ is the size of the locked file.
145 TY is the lock type:
147 r read;
148 rw read and write;
149 w write;
150 ? unknown.
151 M is the mandatory state of the lock: 0 if none; 1 if set. (See
153 chmod(1)).
154 ST is the relative byte offset of the lock.
156 WH is the starting offset (``whence'') of the lock.
158 END is the ending offset of the lock.
160 LEN is the length of the lock.
162 NAME is the name of the locked file, if it was specified as a path
164 argument.
165 If there is no path argument name, then the mount point and
167 device paths of the file system on which the locked file
168 resides are displayed.
169
171 Lslk can be blocked by some kernel functions that it uses - lstat(2),
172 readlink(2), and stat(2). These functions are stalled in the kernel,
173 for example, when the hosts where mounted NFS file systems reside
174 become inaccessible.
175 Lslk attempts to break these blocks with timers and child processes,
177 but the techniques are not wholly reliable. When lslk does manage to
178 break a block, it will report the break with an error message. The
179 messages may be suppressed with the -w option.
180 The default timeout value may be displayed with the -h option, and it
182 may be changed with the -S [t] option. The minimum for t is two sec‐
183 onds, but you should avoid small values, since slow system responsive‐
184 ness can cause short timeouts to expire unexpectedly and perhaps stop
185 lslk before it can produce any output.
186 When lslk has to break a block during its access of mounted file system
188 information, it normally continues, although with less information
189 available to display about open files.
190 Lslk can also be directed to avoid the protection of timers and child
192 processes when using the kernel functions that might block by specify‐
193 ing the -O option. While this will allow lslk to start up with less
194 overhead, it exposes lslk completely to the kernel situations that
195 might block it. Use this option cautiously.
196
198 You can use the -b option to tell lslk to avoid using kernel functions
199 that would block. Some cautions apply.
200 First, using this option usually requires that your system supply
202 alternate device numbers in place of the device numbers that lslk would
203 normally obtain with the lstat(2) and stat(2) kernel functions. See
204 the ALTERNATE DEVICE NUMBERS section for more information on alternate
205 device numbers.
206 Second, you can't specify the names of files you want lslk to locate
208 locks for unless they're file system names. This is because lslk needs
209 to know the device and inode numbers of files listed with names in the
210 lslk options, and the -b option prevents lslk from obtaining them.
211 Moreover, since lslk only has device numbers for the file systems that
212 have alternates, its ability to locate locks on file systems depends
213 completely on the availability and accuracy of the alternates. If no
214 alternates are available, or if they're incorrect, lslk won't be able
215 to locate locks on the named file systems.
216 Third, if the names of your file system directories that lslk obtains
218 from your system's mount table are symbolic links, lslk won't be able
219 to resolve the links. This is because the -b option causes lslk to
220 avoid the kernel readlink(2) function it uses to resolve symbolic
221 links.
222 Finally, using the -b option causes lslk to issue warning messages when
224 it needs to use the kernel functions that the -b option directs it to
225 avoid. You can suppress these messages by specifying the -w option,
226 but if you do, you won't see the alternate device numbers reported in
227 the warning messages.
228
230 On some dialects, when lslk has to break a block because it can't get
231 information about a mounted file system via the lstat(2) and stat(2)
232 kernel functions, or because you specified the -b option, lslk can
233 obtain some of the information it needs - the device number and possi‐
234 bly the file system type - from the system mount table. When that is
235 possible, lslk will report the device number it obtained. (You can
236 suppress the report by specifying the -w option.)
237 You can assist this process if your mount table is supported with an
239 /etc/mtab or /etc/mnttab file that contains an options field by adding
240 a ``dev=xxxx'' field for mount points that do not have one in their
241 options strings.
242 The ``xxxx'' portion of the field is the hexadecimal value of the file
244 system's device number. (Consult the st_dev field of the output of the
245 lstat(2) and stat(2) functions for the appropriate values for your file
246 systems.) Here's an example from a Solaris 2.5 /etc/mnttab for a UFS
247 file system:
248 ... ufs suid,rw,dev=80001f ...
250 Some dialects that do not use an ASCII /etc/mtab or /etc/mnttab file
252 for the mount table may still provide an alternative device number in
253 their internal mount tables. This includes AIX, DEC OSF/1, Digital
254 UNIX, and Tru64 UNIX. Lslk knows how to obtain the alternative device
255 number for these dialects and uses it when its attempt to lstat(2) or
256 stat(2) the file system is blocked.
257 If you're not sure your dialect supplies alternate device numbers for
259 file systems from its mount table, use this lslk incantation to see if
260 it reports any alternate device numbers:
261 lslk -b
263 Look for standard error file warning messages that begin ``assuming
265 "dev=xxxx" from ...''.
266
268 Errors are identified with messages on the standard error file.
269 Lslk returns a one (1) if an error was detected or if it couldn't list
271 lock information for all the names that were specified.
272
274 To list all locks, use:
275 lslk
277 To list locks from the host ``klaatu'' in the local domain, use:
279 lslk -i klaatu
281 To list locks from the hosts helios.cc.purdue.edu and vic1.cc.pur‐
283 due.edu, use:
284 lslk -i helios.cc.purdue.edu -i vic1.cc.purdue.edu
286 To list locks held by processes 1234 and 56789, use:
288 lslk -p 1234,56789
290 To list all locks held by process 1234 on host klaatu, use:
292 lslk -p 1234 -a -i klaatu
294
296 Lslk must have permission to access the system memory files - e.g.,
297 /dev/kmem and /dev/mem. Permission to do that is granted when the lslk
298 process is run from a root shell, or when its ``setgid'' group matches
299 the group (e.g., ``sys'') that can read the system memory files.
300
302 Perhaps it should be possible to specify the host on which a search
303 target PID is located.
304 DEC OSF/1, Digital UNIX, and Tru64 UNIX lslk won't find locks applied
306 with the flock(2) function. It will find locks applied with the
307 fcntl(2) and lockf(3) functions.
308 Linux lslk will not report locks held by NFS clients. It may have dif‐
310 ficulty reporting locks held on dynamic inodes (e.g., for the Win-95
311 file system type, smbfs).
312 Solaris lslk won't find locks held on local Veritas VxFS files
314 by local or remote processes.
315
317 /dev/kmem kernel virtual memory device
318 /dev/mem physical memory device
320
322 Lslk was written by Victor A. Abell <abe@purdue.edu> of the Purdue Uni‐
323 versity Computing Center (PUCC).
324 Chris Eleveld <chris@sector7.com> did the DEC OSF/1, Digital UNIX,
326 Linux, and Tru64 UNIX ports.
327
329 chmod(1), fcntl(2), fcntl(5), flock(3B), lockd(1M), lstat(2),
330 lockf(3C), readlink(2), stat(2).
331 Revision-1.29 LSLK(8)