proc

Members

(static) SIGABRT :number

Source:
Default Value:
  • 6
Type:
  • number

(static) SIGALRM :number

Source:
Default Value:
  • 14
Type:
  • number

(static) SIGBUS :number

Source:
Default Value:
  • 7
Type:
  • number

(static) SIGCHLD :number

Source:
Default Value:
  • 17
Type:
  • number

(static) SIGCONT :number

Source:
Default Value:
  • 18
Type:
  • number

(static) SIGFPE :number

Source:
Default Value:
  • 8
Type:
  • number

(static) SIGHUP :number

Source:
Default Value:
  • 1
Type:
  • number

(static) SIGILL :number

Source:
Default Value:
  • 4
Type:
  • number

(static) SIGINT :number

Source:
Default Value:
  • 2
Type:
  • number

(static) SIGIO :number

Source:
Default Value:
  • 29
Type:
  • number

(static) SIGIOT :number

Source:
Default Value:
  • 6
Type:
  • number

(static) SIGKILL :number

Source:
Default Value:
  • 9
Type:
  • number

(static) SIGPIPE :number

Source:
Default Value:
  • 13
Type:
  • number

(static) SIGPOLL :number

Source:
Default Value:
  • 29
Type:
  • number

(static) SIGPROF :number

Source:
Default Value:
  • 27
Type:
  • number

(static) SIGPWR :number

Source:
Default Value:
  • 30
Type:
  • number

(static) SIGQUIT :number

Source:
Default Value:
  • 3
Type:
  • number

(static) SIGSEGV :number

Source:
Default Value:
  • 11
Type:
  • number

(static) SIGSTKFLT :number

Source:
Default Value:
  • 16
Type:
  • number

(static) SIGSTOP :number

Source:
Default Value:
  • 19
Type:
  • number

(static) SIGSYS :number

Source:
Default Value:
  • 31
Type:
  • number

(static) SIGTERM :number

Source:
Default Value:
  • 15
Type:
  • number

(static) SIGTRAP :number

Source:
Default Value:
  • 5
Type:
  • number

(static) SIGTSTP :number

Source:
Default Value:
  • 20
Type:
  • number

(static) SIGTTIN :number

Source:
Default Value:
  • 21
Type:
  • number

(static) SIGTTOU :number

Source:
Default Value:
  • 22
Type:
  • number

(static) SIGUNUSED :number

Source:
Default Value:
  • 31
Type:
  • number

(static) SIGURG :number

Source:
Default Value:
  • 23
Type:
  • number

(static) SIGUSR1 :number

Source:
Default Value:
  • 10
Type:
  • number

(static) SIGUSR2 :number

Source:
Default Value:
  • 12
Type:
  • number

(static) SIGVTALRM :number

Source:
Default Value:
  • 26
Type:
  • number

(static) SIGWINCH :number

Source:
Default Value:
  • 28
Type:
  • number

(static) SIGXCPU :number

Source:
Default Value:
  • 24
Type:
  • number

(static) SIGXFSZ :number

Source:
Default Value:
  • 25
Type:
  • number

(static) WCONTINUED :number

Source:
Default Value:
  • 8

Also return if a stopped child has been resumed by delivery of SIGCONT (since Linux 2.6.10)

Type:
  • number

(static) WNOHANG :number

Source:
Default Value:
  • 1

Return immediately if no child has exited

Type:
  • number

(static) WUNTRACED :number

Source:
Default Value:
  • 2

Also return if a child has stopped (but not traced via ptrace(2))

Type:
  • number

Methods

(static) alarm(seconds) → {number}

Source:

The alarm() function shall cause the system to generate a SIGALRM signal for the process after the number of realtime seconds specified by seconds have elapsed.

Processor scheduling delays may prevent the process from handling the signal as soon as it is generated.

If seconds is 0, a pending alarm request, if any, is canceled.

Alarm requests are not stacked; only one SIGALRM generation can be scheduled in this manner. If the SIGALRM signal has not yet been generated, the call shall result in rescheduling the time at which the SIGALRM signal is generated.

Parameters:
Name Type Description
seconds number
Returns:

If there is a previous alarm() request with time remaining, alarm() shall return a non-zero value that is the number of seconds until the previous request would have generated a SIGALRM signal.

Otherwise, alarm() shall return 0.

Type
number

(static) atexit(inheritopt, fn) → {void}

Source:

Register function handlers for the exit process event.

Note that, unlike the libc atexit() function, this one only invokes handlers which have been registered for the current process, and not its children.

In libc's atexit(), all handlers are inherited when a fork() is done, leading to children process to execute atexit() handlers too. In this framework, the default is not to inherit unless requested with inherit = true.

Parameters:
Name Type Attributes Default Description
inherit boolean <optional>
 false

Whether to inherit the handler in forked children
fn function

Handler function
Returns:
Type
void

(static) chdir() → {number}

Source:

Change process working directory.

Throws:
SysError
Returns:

0

Type
number

(static) exec(executable, argsopt, optsopt)

Source:

Replace the current process image with a new process image.

Note that this function either fails or doesn't return ever because it replaces the current process image.

Parameters:
Name Type Attributes Default Description
executable string

Path or name of executable
args Array.<string> <optional>
 []

Array of arguments to pass to program (not including argv[0]).
opts ProcExecOptions <optional>
 {}

Options for process execution.
Throws:
SysError

(static) exit(statusopt)

Source:

End current process returning given status code.

Note that this function doesn't return ever because it finishes the process.

Parameters:
Name Type Attributes Default Description
status number <optional>
 0

Status code to return to kernel

(static) fork(waitopt, fnopt) → {number|ProcResult}

Source:

This function creates a new process.

Examples
// Fork and return immediately (old school fork)
const pid = proc.fork();
if (pid === 0) {
  // Run child code
  ...
} else {
  // Run parent code
  ...

  // Wait for child to finish
  proc.waitpid(pid);
}
const pid = proc.fork(function() {
  // Run child code
  ...
});

// Wait for child to finish
proc.waitpid(pid);
const result = proc.fork(true, function() {
  // Run child code
  ...
});

// Check result
if (result.exit_status !== 0) {
  ...
}
Parameters:
Name Type Attributes Description
wait true <optional>

Pass true to wait for child to finish. Can only be given if fn is given since it doesn't make sense to wait for an empty child.
fn function <optional>

The function that implements the child process. If not given, the method returns and the return code must be inspected to decide whether to execute parent or child code.
Throws:
SysError
Returns:

If wait is true returns the result of proc.waitpid(), otherwise, the return value is 0 in the child and the pid of the child in the parent.

Type
number | ProcResult

(static) fork2(getpidopt, fn) → {void|number}

Source:

Double fork idiom used to launch detached (daemonized) processes. Note that it has builtin support to obtain the child pid if requested.

Examples
proc.fork2(function() {
  // Run fire and forget daemon
  ...
});
const pid = proc.fork2(true, function() {
  // Run managed daemon
  ...
});

...

// Kill daemon
proc.kill(pid);
Parameters:
Name Type Attributes Description
getpid true <optional>

Pass true to make the function return daemon's pid
fn function

The function that implements daemon's code
Throws:
SysError
Returns:

pid of daemon if getpid = true

Type
void | number

(static) getegid() → {number}

Source:

Get the effective group id of the running process.

Returns:

A group id

Type
number

(static) getenv(name) → {string|null}

Source:

Get the value of an environment variable

Parameters:
Name Type Description
name string

The name of the environment variable
Returns:

The value of the environment variable

Type
string | null

(static) geteuid() → {number}

Source:

Get the effective user id of the running process.

Returns:

A user id

Type
number

(static) getgid() → {number}

Source:

Get the group id of the running process.

Returns:

A group id

Type
number

(static) getpid() → {number}

Source:

Get the pid of the running process.

Returns:

A process id

Type
number

(static) getppid() → {number}

Source:

Get the pid of the parent process.

Returns:

A process id

Type
number

(static) getuid() → {number}

Source:

Get the user id of the running process.

Returns:

A user id

Type
number

(static) kill(pid, sig) → {0}

Source:

The kill() function can be used to send any signal to any process group or process.

For a process to have permission to send a signal, it must either be privileged (under Linux: have the CAP_KILL capability in the user namespace of the target process), or the real or effective user ID of the sending process must equal the real or saved set-user-ID of the target process. In the case of SIGCONT, it suffices when the sending and receiving processes belong to the same session.

Parameters:
Name Type Description
pid number

If pid is positive, then signal sig is sent to the process with the ID specified by pid.

If pid equals 0, then sig is sent to every process in the process group of the calling process.

If pid equals -1, then sig is sent to every process for which the calling process has permission to send signals, except for process 1 (init), but see below.

If pid is less than -1, then sig is sent to every process in the process group whose ID is -pid.
sig number

If sig is 0, then no signal is sent, but existence and permission checks are still performed; this can be used to check for the existence of a process ID or process group ID that the caller is permitted to signal.
Throws:
SysError
Returns:
Type
0

(static) setenv(name, value, overwriteopt) → {0}

Source:

Set an environment variable.

Parameters:
Name Type Attributes Default Description
name string

Name of variable
value string | null

Value to set or null to unset
overwrite boolean <optional>
 true

Whether to overwrite the value if it exists
Throws:

SysError

Returns:
Type
0

(static) setsid() → {number}

Source:

Creates a new session if the calling process is not a process group leader. The calling process is the leader of the new session (i.e., its session ID is made the same as its process ID).

The calling process also becomes the process group leader of a new process group in the session (i.e., its process group ID is made the same as its process ID).

The calling process will be the only process in the new process group and in the new session.

Initially, the new session has no controlling terminal. For details of how a session acquires a controlling terminal, see credentials(7).

Throws:

SysError

Returns:

The (new) session ID of the calling process

Type
number

(static) signal(sig, func) → {void}

Source:

The signal() function chooses one of three ways in which receipt of the signal number sig is to be subsequently handled.

Parameters:
Name Type Description
sig number

The signal number
func undefined | null | function

If the value of func is undefined, default handling for that signal shall occur.

If the value of func is null, the signal shall be ignored.

Otherwise, the application shall ensure that func points to a function to be called when that signal occurs.
Throws:

SysError

Returns:
Type
void

(static) sleep(seconds) → {0}

Source:

Pause execution of the running process for a given number of seconds.

Parameters:
Name Type Description
seconds number

Seconds to wait
Throws:

SysError

Returns:
Type
0

(static) unsetenv(name) → {0}

Source:

Delete an environment variable.

Parameters:
Name Type Description
name string

Name of environment variable
Throws:

SysError

Returns:
Type
0

(static) waitpid(pid, options) → {ProcResult}

Source:
Parameters:
Name Type Description
pid number

< -1 meaning wait for any child process whose process group ID is equal to the absolute value of pid.

-1 meaning wait for any child process.

0 meaning wait for any child process whose process group ID is equal to that of the calling process at the time of the call to waitpid().

> 0 meaning wait for the child whose process ID is equal to the value of pid.
options number

Zero or an OR of proc.WNOHANG, proc.WUNTRACED, or proc.WCONTINUED.
Throws:

SysError

Returns:
Type
ProcResult