Module lposix
Functions
abort () | Abort the program immediately. |
raise (nsig) | Raise a signal on this process. |
isgraph (character) | Check for any printable character except space. |
isprint (character) | Check for any printable character including space. |
errno (n) | Describe an error code/and or read errno |
set_errno (n) | Set errno. |
realpath (path) | Find canonicalized absolute pathname. |
basename (path) | File part of path. |
dirname (path) | Directory name of path. |
dir (path) | Contents of directory. |
fnmatch (pat, name, flags) | Match a filename against a shell pattern. |
glob (pat) | Find all files in this directory matching a shell pattern. |
files (path) | Iterator over all files in this directory. |
getcwd () | Current working directory for this process. |
mkdir (path) | Make a directory. |
chdir (path) | Set the working directory. |
rmdir (path) | Remove a directory. |
unlink (path) | Unlink a file. |
link (target, link, soft) | Create a link. |
readlink (path) | Read value of a symbolic link. |
access (path, mode) | Check real user's permissions for a file. |
fileno (file) | File descriptor corresponding to a Lua file object. |
mkfifo (path) | Make a FIFO pipe. |
mkstemp (templ) | Create a unique temporary file. |
mkdtemp (templ) | Create a unique temporary directory. |
exec (path, ..., t) | Execute a program without using the shell. |
execp (path, ..., t) | Execute a program using the shell. |
fork () | Fork this program. |
_exit (return) | Terminate the calling process. |
rpoll (file, timeout) | Wait for some event on a file descriptor. |
poll (list, timeout) | Wait for events on multiple file descriptors. |
wait (pid) | Wait for the given process. |
kill (pid, sig) | Send a signal to the given process. |
killpg (pgrp, sig) | Send a signal to the given process group. |
setpid (what, id, gid) | Set the uid, euid, gid, egid, sid or pid & gid. |
sleep (seconds) | Sleep for a number of seconds. |
nanosleep (seconds, nanoseconds) | Sleep with nanosecond precision. |
msgget (key, flags, mode) | Get a message queue identifier |
msgsnd (id, type, message, flags) | Send message to a message queue |
msgrcv (id, size, type, flags) | Receive message from a message queue |
setenv (name, value, over) | Set an environment variable for this process. |
getenv (name) | Get value of environment variable, or all variables. |
umask (mode) | Set file mode creation mask. |
openpt (oflags) | Open a pseudoterminal. |
grantpt (file) | Grant access to a slave pseudoterminal |
unlockpt (file) | Unlock a pseudoterminal master/slave pair |
ptsname (file) | Get the name of a slave pseudo-terminal |
open (path, oflags, mode) | Open a file. |
close (fd) | Close an open file descriptor. |
dup (fd) | Duplicate an open file descriptor. |
dup2 (oldfd, newfd) | Duplicate one open file descriptor to another, closing the new one if necessary. |
pipe () | Creates a pipe. |
chmod (path, mode) | Change the mode of the path. |
read (fd, count) | Read bytes from a file. |
write (fd, buf) | Write bytes to a file. |
chown (path, uid, gid) | Change ownership of a file. |
utime (path, mtime, atime) | Change file last access and modification times. |
getpid (...) | Get process identifiers. |
hostid () | Get host id. |
ttyname (fd) | Name of a terminal device. |
ctermid () | Name of controlling terminal. |
getpasswd (user, ...) | Get the password entry for a user. |
getgroup (group) | Information about a group. |
getgroups () | Get list of supplementary group IDs. |
times (...) | Get the current process times. |
stat (path, ...) | Information about an existing file path. |
statvfs (path, ...) | Get file system statistics. |
fcntl (fd, cmd, arg) | Manipulate file descriptor. |
isatty (fd) | Test whether a file descriptor refers to a terminal. |
uname (optional) | Return information about this machine. |
pathconf (path, ...) | Get a value for a configuration option for a filename. |
sysconf (...) | Get configuration information at runtime. |
openlog (ident, option, facility) | Open the system logger. |
syslog (priority, message) | Write to the system logger. |
closelog () | Close system log. |
setlogmask (bitwise) | Set log priority mask. |
crypt (string, salt) | Encrypt a password. |
setrlimit (resource, softlimit, hardlimit) | Set a resource limit for subsequent child processes. |
getrlimit (resource) | Get resource limits for this process. |
Time and date
gettimeofday () | Get time of day. |
time () | Get current time. |
localtime (t) | Convert time in seconds to table. |
gmtime (t) | Convert UTC time in seconds to table. |
clock_getres (name) | Find the precision of a clock. |
clock_gettime (name) | Read a clock. |
strftime (tm) | Write a time out according to a format. |
mktime (tm) | Convert a time table into a time value. |
getopt (arg, shortopts, longopts) | Parse command-line options. |
signal (signum, handler, flags) | Install a signal handler for this signal number. |
sync () | commit buffer cache to disk |
fsync (fd) | synchronize a file's in-core state with storage device |
fdatasync (fd) | synchronize a file's in-core state with storage device without metadata |
lseek (fd, offset, whence) | reposition read/write file offset |
nice (inc) | change process priority |
Functions
- abort ()
-
Abort the program immediately.
see also:
- raise (nsig)
-
Raise a signal on this process.
Parameters:
- nsig int
Returns:
-
integer error code
see also:
- isgraph (character)
-
Check for any printable character except space.
Parameters:
- character string to check
Returns:
-
true if character is in the class
see also:
- isprint (character)
-
Check for any printable character including space.
Parameters:
- character string to check
Returns:
-
true if character is in the class
see also:
- errno (n)
-
Describe an error code/and or read errno
Parameters:
- n int optional error code (default: current value of errno )
Returns:
- description
- error code
see also:
- set_errno (n)
-
Set errno.
Parameters:
- n int error code
see also:
- realpath (path)
-
Find canonicalized absolute pathname.
Parameters:
- path string
Returns:
- canonicalized absolute path, or nil on error
- error message if failed
see also:
- basename (path)
-
File part of path.
Parameters:
- path string
Returns:
-
file part
see also:
- dirname (path)
-
Directory name of path.
Parameters:
- path string
Returns:
-
directory part
see also:
- dir (path)
-
Contents of directory.
Parameters:
- path string optional (default .)
Returns:
-
contents as table
see also:
- fnmatch (pat, name, flags)
-
Match a filename against a shell pattern.
Parameters:
Returns:
-
true or false
Raises:
error if fnmatch failedsee also:
- glob (pat)
-
Find all files in this directory matching a shell pattern.
Parameters:
- pat string shell pattern
Returns:
-
table of matching filenames
see also:
- files (path)
-
Iterator over all files in this directory.
Parameters:
- path string optional (default .)
Returns:
-
an iterator
- getcwd ()
-
Current working directory for this process.
Returns:
-
path
see also:
- mkdir (path)
-
Make a directory.
Parameters:
- path string
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- chdir (path)
-
Set the working directory.
Parameters:
- path string
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
Usage:
status, errstr, errno = posix.chdir("/var/tmp")
- rmdir (path)
-
Remove a directory.
Parameters:
- path string
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- unlink (path)
-
Unlink a file.
Parameters:
- path string
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- link (target, link, soft)
-
Create a link.
Parameters:
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- readlink (path)
-
Read value of a symbolic link.
Parameters:
- path string
Returns:
- link target on success, error otherwise
- error message if failed
see also:
- access (path, mode)
-
Check real user's permissions for a file.
Parameters:
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
Usage:
status, errstr, errno = posix.access("/etc/passwd", "rw")
- fileno (file)
-
File descriptor corresponding to a Lua file object.
Parameters:
- file Lua file object
Returns:
- handle on success, nil otherwise
- error message if failed.
- mkfifo (path)
-
Make a FIFO pipe.
Parameters:
- path string
Returns:
- handle on success, nil otherwise
- error message if failed.
see also:
- mkstemp (templ)
-
Create a unique temporary file.
Parameters:
- templ string pattern that ends in "XXXXXX"
Returns:
- file descriptor, nil otherwise
- name on success, error otherwise
see also:
Usage:
posix.mkstemp 'wooXXXXXX'
- mkdtemp (templ)
-
Create a unique temporary directory.
Parameters:
- templ string pattern that ends in six 'X' characters
Returns:
- path on success, nil otherwise
- error message if failed
see also:
- exec (path, ..., t)
-
Execute a program without using the shell.
Parameters:
- path string
- ... any arguments, or
- t table of arguments (can include index 0)
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- execp (path, ..., t)
-
Execute a program using the shell.
Parameters:
- path string
- ... any arguments, or
- t table of arguments (can include index 0)
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- fork ()
-
Fork this program.
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- _exit (return)
-
Terminate the calling process.
Parameters:
- return int status
see also:
- rpoll (file, timeout)
-
Wait for some event on a file descriptor.
Adapted from http://lua-users.org/lists/lua-l/2007-11/msg00346.html
Parameters:
- file int descriptor
- timeout int
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- poll (list, timeout)
-
Wait for events on multiple file descriptors.
Parameters:
- list of file descriptors
- timeout int optional (default -1)
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- wait (pid)
-
Wait for the given process.
Parameters:
- pid int optional (default -1 (any child process))
Returns:
- pid of terminated child, nil on error
- how child ended ("exited", "killed" or "stopped"), or error message on error.
- status value (computed with WEXITSTATUS, WTERMSIG or WSTOPSIG as appropriate), or nothing on error.
see also:
- kill (pid, sig)
-
Send a signal to the given process.
Parameters:
- pid int process id
- sig int optional (default SIGTERM)
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- killpg (pgrp, sig)
-
Send a signal to the given process group.
Parameters:
- pgrp int group id
- sig int optional (default SIGTERM)
Returns:
- return code, nil otherwise
- error message if failed.
see also:
- setpid (what, id, gid)
-
Set the uid, euid, gid, egid, sid or pid & gid.
Parameters:
- what string one of 'u', 'U', 'g', 'G', 's', 'p' (upper-case means "effective")
- id
(uid, gid or pid for every value of
what
except 's') - gid
(only for
what
value 'p')
Returns:
- 0 on success, nil otherwise
- error message if failed
see also:
- sleep (seconds)
-
Sleep for a number of seconds.
Parameters:
- seconds int
Returns:
-
code
see also:
- nanosleep (seconds, nanoseconds)
-
Sleep with nanosecond precision.
Parameters:
- seconds int
- nanoseconds int
Returns:
- 0 on success, nil otherwise
-
error message if failed, or the remaining time as two
results
tv_sec
,tv_nsec
if return value isEINTR
.
see also:
- msgget (key, flags, mode)
-
Get a message queue identifier
Parameters:
- key int
- flags int (optional, default - 0)
- mode int (optional, default - 0777)
Returns:
- message queue identifier on success
- nil and error message if failed
see also:
- msgsnd (id, type, message, flags)
-
Send message to a message queue
Parameters:
- id
int
- message queue identifier returned by msgget
- type
int
- message type
- message string
- flags int (optional, default - 0)
Returns:
- 0 on success
- nil and error message if failed
see also:
- id
int
- msgrcv (id, size, type, flags)
-
Receive message from a message queue
Parameters:
- id
int
- message queue identifier returned by msgget
- size
int
- maximum message size
- type
int
- message type (optional, default - 0)
- flags int (optional, default - 0)
Returns:
- message type and message text on success
- nil, nil and error message if failed
see also:
- id
int
- setenv (name, value, over)
-
Set an environment variable for this process.
(Child processes will inherit this)
Parameters:
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- getenv (name)
-
Get value of environment variable, or all variables.
Parameters:
- name string if nil, get all
Returns:
-
value if name given, otherwise a name-indexed table of values.
see also:
Usage:
for a,b in pairs(posix.getenv()) do print(a, b) end
- umask (mode)
-
Set file mode creation mask.
Parameters:
- mode string optional file creation mask string (default current mask; see chmod for format)
Returns:
-
previous umask
see also:
- openpt (oflags)
-
Open a pseudoterminal.
Parameters:
- oflags
int
bitwise OR of the values
O_RDWR
, and possiblyO_NOCTTY
(all in the library's namespace)
Returns:
- file descriptor on success, nil otherwise
- error message if failed.
see also:
- oflags
int
bitwise OR of the values
- grantpt (file)
-
Grant access to a slave pseudoterminal
Parameters:
- file descriptor returned by opening /dev/ptmx
Returns:
- 0 on success
- nil, error message if failed.
see also:
- unlockpt (file)
-
Unlock a pseudoterminal master/slave pair
Parameters:
- file descriptor returned by opening /dev/ptmx
Returns:
- 0 on success
- nil, error message if failed.
see also:
- ptsname (file)
-
Get the name of a slave pseudo-terminal
Parameters:
- file descriptor returned by opening /dev/ptmx
Returns:
- path name of the slave terminal device
- nil, error message if failed.
see also:
- open (path, oflags, mode)
-
Open a file.
Parameters:
- path string
- oflags
int
bitwise OR of the values
O_RDONLY
,O_WRONLY
,O_RDWR
,O_APPEND
,O_CREAT
,O_DSYNC
,O_EXCL
,O_NOCTTY
,O_NONBLOCK
,O_RSYNC
,O_SYNC
,O_TRUNC
(all in the library's namespace) - mode
string
(used with
O_CREAT
; see chmod for format)
Returns:
- file descriptor on success, nil otherwise
- error message if failed.
see also:
- close (fd)
-
Close an open file descriptor.
Parameters:
- fd int
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- dup (fd)
-
Duplicate an open file descriptor.
Parameters:
- fd int
Returns:
- file descriptor on success, nil otherwise
- error message if failed.
see also:
- dup2 (oldfd, newfd)
-
Duplicate one open file descriptor to another, closing the new one if necessary.
Parameters:
- oldfd int
- newfd int
Returns:
- new file descriptor on success, nil otherwise
- error message if failed.
see also:
- pipe ()
-
Creates a pipe.
Returns:
- fd read end
- fd write end
see also:
- chmod (path, mode)
-
Change the mode of the path. Modes are specified in one of the following formats:
- "rwxrwxrwx" (e.g. "rw-rw-w--")
- "ugoa+-=rwx" (e.g. "u+w")
- "+-=rwx" (e.g. "+w")
Parameters:
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
Usage:
posix.chmod('bin/dof','+x')
- read (fd, count)
-
Read bytes from a file.
Parameters:
- fd int the file descriptor
- count int number of bytes to read
Returns:
-
string with at most
count
bytes, or nil on error - error message if failed
see also:
- write (fd, buf)
-
Write bytes to a file.
Parameters:
- fd int the file descriptor
- buf string containing bytes
Returns:
- number of bytes written on success, nil otherwise
- error message if failed.
see also:
- chown (path, uid, gid)
-
Change ownership of a file.
Parameters:
- path string existing file path
- uid (string or number)
- gid (string or number)
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
Usage:
print(posix.chown("/etc/passwd",100,200)) -- will fail for a normal user, and hence print an error
- utime (path, mtime, atime)
-
Change file last access and modification times.
Parameters:
- path string existing file path
- mtime int optional modification time (default current time)
- atime int optional access time (default current time)
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- getpid (...)
-
Get process identifiers.
Parameters:
- ... string types, each one of "egid", "euid", "gid", "uid", "pgrp", "pid", "ppid"
Returns:
-
... values, or table of all ids if no option given
Usage:
posix.getpid 'pid' -- PID of current process
- hostid ()
-
Get host id.
Returns:
-
host id
see also:
- ttyname (fd)
-
Name of a terminal device.
Parameters:
- fd int optional file descriptor (default 0)
Returns:
-
string name
see also:
- ctermid ()
-
Name of controlling terminal.
Returns:
-
code
see also:
- getpasswd (user, ...)
-
Get the password entry for a user.
Parameters:
- user (name or id)
- ... string field names, each one of "uid", "name", "gid", "passwd", "dir", "shell"
Returns:
-
... values, or table of all fields if no option given
Usage:
for a,b in pairs(posix.getpasswd("root")) do print(a,b) end
print(posix.getpasswd("root", "shell"))
- getgroup (group)
-
Information about a group.
Parameters:
- group id or name
Returns:
-
table
{name=name,gid=gid,0=member0,1=member1,...}
- getgroups ()
-
Get list of supplementary group IDs.
Returns:
-
table of group IDs.
see also:
- times (...)
-
Get the current process times.
Parameters:
- ... string field names, each one of "utime", "stime", "cutime", "cstime", "elapsed"
Returns:
-
... times, or table of all times if no option given
see also:
- stat (path, ...)
-
Information about an existing file path.
Parameters:
- path string file path
- ... string field names, each one of "mode", "ino", "dev", "nlink", "uid", "gid", "size", "atime", "mtime", "ctime", "type"
Returns:
-
... values, or table of all fields if no option given
see also:
Usage:
for a, b in pairs(posix.stat("/etc/")) do print(a, b) end
- statvfs (path, ...)
-
Get file system statistics.
Parameters:
- path string any path within the mounted file system
- ... string field names, each one of "bsize", "frsize", "blocks", "bfree", "bavail", "files", "ffree", "favail", "fsid", "flag", "namemax"
Returns:
-
... values, or table of all fields if no option given
see also:
- fcntl (fd, cmd, arg)
-
Manipulate file descriptor.
Parameters:
- fd int file descriptor to act on
- cmd int operation to perform
- arg
optional (default 0). Type and meaning of this param depends on
cmd
. Currently it expects arg to be a table for file lock relatedcmd
and a number for all the rest. With file lockcmd
the table should contain fields for flock structure (see example). When function returns the fields of the table get updated with corresponding values from flock structure (to comply with semantics of F_GETLK).
Returns:
-
integer return value depending on
cmd
, or nil on error - error message if failed
see also:
- isatty (fd)
-
Test whether a file descriptor refers to a terminal.
Parameters:
- fd int file descriptor to test
Returns:
- 1 if fd is an open file descriptor referring to a terminal, or nil otherwise
- error message if failed
see also:
- uname (optional)
-
Return information about this machine.
Parameters:
- optional
string
, contains zero or more of:
- %m machine name
- %n node name
- %r release
- %s sys name
- %v version
(default return all information available)
Returns:
- information string on success, nil otherwise
- error message if failed
see also:
- optional
string
, contains zero or more of:
- pathconf (path, ...)
-
Get a value for a configuration option for a filename.
Parameters:
- path string optional (default ".")
- ... string field names, each one of "LINKMAX", "MAXCANON", "NAMEMAX", "PIPEBUF", "CHOWNRESTRICTED", "NOTRUNC", "VDISABLE"
Returns:
-
... values, or table of all fields if no option given
see also:
Usage:
for a, b in pairs(posix.pathconf("/dev/tty")) do print(a, b) end
- sysconf (...)
-
Get configuration information at runtime.
Parameters:
- ... string field names, each one of "ARGMAX", "CHILDMAX", "CLKTCK", "NGROUPSMAX", "STREAMMAX", "TZNAMEMAX", "OPENMAX", "JOBCONTROL", "VERSION"
Returns:
-
... values, or table of all fields no option
see also:
- openlog (ident, option, facility)
-
Open the system logger.
Parameters:
- ident string all messages will start with this
- option string optional, any combination of 'c' (directly to system console if an error sending), 'n' (no delay) or 'p' (show PID)
- facility int optional (default LOG_USER)
see also:
- syslog (priority, message)
-
Write to the system logger.
Parameters:
- priority
int
one of these values:
- 1 Alert - immediate action
- 2 Critcal
- 3 Error
- 4 Warning
- 5 Notice
- 6 Informational
- message string
see also:
- priority
int
- closelog ()
-
Close system log.
see also:
- setlogmask (bitwise)
-
Set log priority mask.
Parameters:
- bitwise
int
OR of values from
LOG_EMERG
,LOG_ALERT
,LOG_CRIT
,LOG_WARNING
,LOG_NOTICE
,LOG_INFO
,LOG_DEBUG
Returns:
- 0 on success, nil otherwise
- error message if failed.
- bitwise
int
OR of values from
- crypt (string, salt)
-
Encrypt a password.
Not recommended for general encryption purposes.
Parameters:
Returns:
-
encrypted string
see also:
- setrlimit (resource, softlimit, hardlimit)
-
Set a resource limit for subsequent child processes.
Parameters:
- resource string one of "core", "cpu", "data", "fsize", "nofile", "stack", "as"
- softlimit optional (default keep current limit)
- hardlimit optional (default keep current limit)
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
Usage:
posix.setrlimit("nofile", 1000, 2000)
- getrlimit (resource)
-
Get resource limits for this process.
Parameters:
- resource string one of "core", "cpu", "data", "fsize", "nofile", "stack", "as"
Returns:
- softlimit, or nil if error
- hardlimit, or message on error
Time and date
Time and date.- gettimeofday ()
-
Get time of day.
Returns:
- time in seconds
- remainder in nanoseconds
see also:
- time ()
-
Get current time.
Returns:
-
time in seconds since epoch
- localtime (t)
-
Convert time in seconds to table.
Parameters:
- t time in seconds since epoch (default now)
Returns:
-
time table: contains "is_dst","yearday","hour","min","year","month",
"sec","weekday","monthday", "day" (the same as "monthday")
- gmtime (t)
-
Convert UTC time in seconds to table.
Parameters:
- t time in seconds since epoch (default now)
Returns:
-
time table as in localtime
- clock_getres (name)
-
Find the precision of a clock.
Parameters:
- name string of clock, one of "monotonic", "processcputimeid", or "threadcputimeid", or nil for realtime clock.
Returns:
- seconds, or nil on error
- nanoseconds, or message on error
- clock_gettime (name)
-
Read a clock.
Parameters:
- name string of clock, one of "monotonic", "processcputimeid", or "threadcputimeid", or nil for realtime clock.
Returns:
- seconds, or nil on error
- nanoseconds, or message on error
- strftime (tm)
-
Write a time out according to a format.
Parameters:
- tm optional time table (e.g from localtime ; default current time)
see also:
- mktime (tm)
-
Convert a time table into a time value.
Parameters:
- tm time table as in localtime
Returns:
-
time in seconds since epoch
- getopt (arg, shortopts, longopts)
-
Parse command-line options.
Parameters:
- arg command line arguments
- shortopts string e.g 'ho:v' (colon means 'receives argument')
- longopts
e.g.
{{'help','none',2},...}
see also:
Usage:
for ret, longindex, optind, optarg in posix.getopt (arg, shortopts[, longopts[, opterr[, optind]]]) do ... end
- signal (signum, handler, flags)
-
Install a signal handler for this signal number.
N.B. Although this is the same API as signal(2), it uses sigaction for guaranteed semantics.
Parameters:
- signum int
- handler function
- flags
optional the
sa_flags
element ofstruct sigaction
Returns:
-
previous handler function
see also:
- sync ()
-
commit buffer cache to disk
see also:
- fsync (fd)
-
synchronize a file's in-core state with storage device
Parameters:
- fd int
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- fdatasync (fd)
-
synchronize a file's in-core state with storage device without metadata
Parameters:
- fd int
Returns:
- 0 on success, nil otherwise
- error message if failed.
see also:
- lseek (fd, offset, whence)
-
reposition read/write file offset
Parameters:
- fd int
- offset int
- whence int one of SEEKSET, SEEKCUR or SEEK_END
Returns:
- new offset on success, nil otherwise
- error message if failed.
see also:
- nice (inc)
-
change process priority
Parameters:
- inc int adds inc to the nice value for the calling process
Returns:
- new nice value on success, nil otherwise
- error message if failed.
see also: