Module Async_unix.Unix_syscalls

Unix_syscalls provides an interface to many of the functions in OCaml's standard Unix module. It uses a deferred in the return type of functions that would block. The idea is that in an Async program one does not use the standard Unix module, since in doing so one could accidentally block the whole program.

There are also a number of cosmetic changes (e.g. polymorphic variants) and other improvements (e.g. phantom types on sockets) over the standard Unix module.

module Syscall_result = Core.Unix.Syscall_result
module Exit : module type of Core.Unix.Exit
module Exit_or_signal : module type of Core.Unix.Exit_or_signal
module Exit_or_signal_or_stop : module type of Core.Unix.Exit_or_signal_or_stop
val system : string ‑> Exit_or_signal.t Import.Deferred.t
val system_exn : string ‑> unit Import.Deferred.t
val getpid : unit ‑> Core.Pid.t
val getppid : unit ‑> Core.Pid.t option
val getppid_exn : unit ‑> Core.Pid.t
val this_process_became_child_of_init : ?poll_delay:Core.Time.Span.t ‑> unit ‑> unit Import.Deferred.t

this_process_became_child_of_init returns a deferred that becomes determined when the current process becomes a child of init(8). This is useful to determine if one's parent has died, because in that case init will becomes one's parent.

See Linux_ext.pr_set_pdeathsig : Signal.t -> unit for related way to get information about parent death.

val nice : int ‑> int
val cores : (unit ‑> int Import.Deferred.t) Core.Or_error.t

cores () Returns the number of cores

type open_flag = [
| `Rdonly
| `Wronly
| `Rdwr
| `Nonblock
| `Append
| `Creat
| `Trunc
| `Excl
| `Noctty
| `Dsync
| `Sync
| `Rsync
]
type file_perm = int
val openfile : ?perm:file_perm ‑> string ‑> mode:open_flag list ‑> Fd.t Import.Deferred.t
val with_file : ?exclusive:[ `Read | `Write ] ‑> ?perm:file_perm ‑> string ‑> mode:open_flag list ‑> f:(Fd.t ‑> 'a Import.Deferred.t) ‑> 'a Import.Deferred.t

with_file file ~mode ~perm ~f ?exclusive opens file, and applies f to the resulting file descriptor. When the result of f becomes determined, it closes the descriptor and returns the result of f. If exclusive is supplied, then the file descriptor is locked before calling f and unlocked after calling f.

module Open_flags : module type of Core.Unix.Open_flags
val fcntl_getfl : Fd.t ‑> Open_flags.t Import.Deferred.t

fcntl_getfl and fcntl_setf are deferred wrappers around the corresponding functions in Core.Unix for accessing the open-file-descriptor table.

val fcntl_setfl : Fd.t ‑> Open_flags.t ‑> unit Import.Deferred.t
include module type of Fd.Close

The Close module exists to collect close and its associated types, so they can be easily reused elsewhere, e.g. Unix_syscalls.

type socket_handling =
| Shutdown_socket
| Do_not_shutdown_socket
type file_descriptor_handling =
| Close_file_descriptor of socket_handling
| Do_not_close_file_descriptor
val close : ?file_descriptor_handling:file_descriptor_handling ‑> Fd.t ‑> unit Import.Deferred.t

close t prevents further use of t, and makes shutdown() and close() system calls on t's underlying file descriptor according to the file_descriptor_handling argument and whether or not t is a socket, i.e. kind t = Socket `Active:

        | file_descriptor_handling                     | shutdown() | close() |
        |----------------------------------------------+------------+---------|
        | Do_not_close_file_descriptor                 | no         | no      |
        | Close_file_descriptor Shutdown_socket        | if socket  | yes     |
        | Close_file_descriptor Do_not_shutdown_socket | no         | yes     |

The result of close becomes determined once the system calls complete. It is OK to call close multiple times on the same t; calls subsequent to the initial call will have no effect, but will return the same deferred as the original call.

val lseek : Fd.t ‑> int64 ‑> mode:[< `Set | `Cur | `End ] ‑> int64 Import.Deferred.t
val truncate : string ‑> len:int64 ‑> unit Import.Deferred.t
val ftruncate : Fd.t ‑> len:int64 ‑> unit Import.Deferred.t
val fsync : Fd.t ‑> unit Import.Deferred.t
val fdatasync : Fd.t ‑> unit Import.Deferred.t
val sync : unit ‑> unit Import.Deferred.t
val lockf : ?len:Core.Int64.t ‑> Fd.t ‑> [ `Read | `Write ] ‑> unit Import.Deferred.t

lockf fd read_or_write ?len exclusively locks for reading/writing the section of the open file fd specified by the current file position and len (see man lockf). It returns when the lock has been acquired. It raises if fd is closed.

val try_lockf : ?len:Core.Int64.t ‑> Fd.t ‑> [ `Read | `Write ] ‑> bool

try_lockf fd read_or_write ?len attempts to exclusively lock for reading/writing the section of the open file fd specified by the current file position and len (see man lockf). It returns true if it acquired the lock. It raises if fd is closed.

val test_lockf : ?len:Core.Int64.t ‑> Fd.t ‑> bool

lockf_is_locked fd ?len checks the lock on section of the open file fd specified by the current file position and len (see man lockf). If the section is unlocked or locked by this process, it returns true, else it returns false. It raises if fd is closed.

val unlockf : ?len:Core.Int64.t ‑> Fd.t ‑> unit

unlockf fd ?len unlocks the section of the open file fd specified by the current file position and len (see man lockf). It raises if fd is closed.

module File_kind : sig ... end
module Stats : sig ... end
val fstat : Fd.t ‑> Stats.t Import.Deferred.t
val stat : string ‑> Stats.t Import.Deferred.t
val lstat : string ‑> Stats.t Import.Deferred.t
val isatty : Fd.t ‑> bool Import.Deferred.t
val remove : string ‑> unit Import.Deferred.t
val rename : src:string ‑> dst:string ‑> unit Import.Deferred.t
val chmod : string ‑> perm:file_perm ‑> unit Import.Deferred.t
val fchmod : Fd.t ‑> perm:file_perm ‑> unit Import.Deferred.t
val chown : string ‑> uid:int ‑> gid:int ‑> unit Import.Deferred.t
val fchown : Fd.t ‑> uid:int ‑> gid:int ‑> unit Import.Deferred.t
val access : string ‑> [ `Read | `Write | `Exec | `Exists ] list ‑> (unit, exn) Core.Result.t Import.Deferred.t
val access_exn : string ‑> [ `Read | `Write | `Exec | `Exists ] list ‑> unit Import.Deferred.t
val set_close_on_exec : Fd.t ‑> unit
val clear_close_on_exec : Fd.t ‑> unit
val mkdir : ?p:unit ‑> ?perm:file_perm ‑> string ‑> unit Import.Deferred.t
val rmdir : string ‑> unit Import.Deferred.t
val chdir : string ‑> unit Import.Deferred.t
val getcwd : unit ‑> string Import.Deferred.t
val chroot : string ‑> unit Import.Deferred.t
type dir_handle = Core.Unix.dir_handle
val opendir : string ‑> dir_handle Import.Deferred.t
val readdir_opt : dir_handle ‑> string option Import.Deferred.t

readdir_opt dir_handle returns the next directory member, or None when there are no more directory members to return.

val readdir : dir_handle ‑> string Import.Deferred.t
val rewinddir : dir_handle ‑> unit Import.Deferred.t
val closedir : dir_handle ‑> unit Import.Deferred.t
val pipe : Core.Info.t ‑> ([ `Reader of Fd.t ] * [ `Writer of Fd.t ]) Import.Deferred.t

The info supplied to pipe is debugging information that will be included in the returned Fds.

val mkfifo : ?perm:file_perm ‑> string ‑> unit Import.Deferred.t

Create a named pipe with the given permissions.

val mkstemp : string ‑> (string * Fd.t) Import.Deferred.t

mkstemp prefix creates and opens a unique temporary file with prefix, automatically appending a suffix of six random characters to make the name unique. Unlike C's mkstemp, prefix should not include six X's at the end.

val mkdtemp : string ‑> string Import.Deferred.t
val getgrouplist : string ‑> int ‑> int array Import.Deferred.t
type process_times = Core.Unix.process_times = {
tms_utime : float;

(** User time for the process *)

tms_stime : float;

(** System time for the process *)

tms_cutime : float;

(** User time for the children processes *)

tms_cstime : float;

(** System time for the children processes *)

}

Time functions.

val times : unit ‑> process_times
type tm = Core.Unix.tm = {
tm_sec : int;

(** Seconds 0..59 *)

tm_min : int;

(** Minutes 0..59 *)

tm_hour : int;

(** Hours 0..23 *)

tm_mday : int;

(** Day of month 1..31 *)

tm_mon : int;

(** Month of year 0..11 *)

tm_year : int;

(** Year - 1900 *)

tm_wday : int;

(** Day of week (Sunday is 0) *)

tm_yday : int;

(** Day of year 0..365 *)

tm_isdst : bool;

(** Daylight time savings in effect *)

}
val time : unit ‑> float
val gettimeofday : unit ‑> float
val gmtime : float ‑> tm
val localtime : float ‑> tm
val mktime : tm ‑> float * tm
val utimes : string ‑> access:float ‑> modif:float ‑> unit Import.Deferred.t
type env = Core.Unix.env
include sig ... end
val env_of_sexp : Sexplib.Sexp.t ‑> env
val sexp_of_env : env ‑> Sexplib.Sexp.t
val environment : unit ‑> string array
val getenv : string ‑> string option
val getenv_exn : string ‑> string
val putenv : key:string ‑> data:string ‑> unit
val unsetenv : string ‑> unit
val fork_exec : prog:string ‑> argv:string list ‑> ?use_path:bool ‑> ?env:[ env | `Replace_raw of string list ] ‑> unit ‑> Core.Pid.t Import.Deferred.t

fork_exec ~prog ~argv ?path ?env forks and execs prog with argv, and returns the child pid. If use_path = true (the default) and prog doesn't contain a slash, then fork_exec searches the PATH environment variable for prog. If env is supplied, it specifies the environment when prog is executed.

If env contains multiple bindings for the same variable, the last takes precedence. In the case of `Extend, bindings in env take precedence over the existing environment. See Unix.exec.

type wait_on = [
| `Any
| `Group of Core.Pid.t
| `My_group
| `Pid of Core.Pid.t
]
include sig ... end
val wait_on_of_sexp : Sexplib.Sexp.t ‑> wait_on
val __wait_on_of_sexp__ : Sexplib.Sexp.t ‑> wait_on
val sexp_of_wait_on : wait_on ‑> Sexplib.Sexp.t
val wait : wait_on ‑> (Core.Pid.t * Exit_or_signal.t) Import.Deferred.t
val wait_nohang : wait_on ‑> (Core.Pid.t * Exit_or_signal.t) option
val wait_untraced : wait_on ‑> (Core.Pid.t * Exit_or_signal_or_stop.t) Import.Deferred.t
val wait_nohang_untraced : wait_on ‑> (Core.Pid.t * Exit_or_signal_or_stop.t) option
val waitpid : Core.Pid.t ‑> Exit_or_signal.t Import.Deferred.t

waitpid pid returns a deferred that becomes determined with the child's exit status, when the child process with process id pid exits. waitpid_exn is like waitpid, except the result only becomes determined if the child exits with status zero; it raises if the child terminates in any other way.

val waitpid_exn : Core.Pid.t ‑> unit Import.Deferred.t
module Inet_addr : sig ... end
module Cidr : module type of Core.Unix.Cidr
module Protocol_family : sig ... end
val socketpair : unit ‑> Fd.t * Fd.t
module Socket : sig ... end
val bind_to_interface_exn : (Fd.t ‑> [ `Any | `Interface_name of string ] ‑> unit) Core.Or_error.t
module Host : sig ... end
type socket_domain = Core.Unix.socket_domain =
| PF_UNIX
| PF_INET
| PF_INET6
include sig ... end
val socket_domain_of_sexp : Sexplib.Sexp.t ‑> socket_domain
val sexp_of_socket_domain : socket_domain ‑> Sexplib.Sexp.t
val bin_socket_domain : socket_domain Bin_prot.Type_class.t
val bin_read_socket_domain : socket_domain Bin_prot.Read.reader
val __bin_read_socket_domain__ : (int ‑> socket_domain) Bin_prot.Read.reader
val bin_reader_socket_domain : socket_domain Bin_prot.Type_class.reader
val bin_size_socket_domain : socket_domain Bin_prot.Size.sizer
val bin_write_socket_domain : socket_domain Bin_prot.Write.writer
val bin_writer_socket_domain : socket_domain Bin_prot.Type_class.writer
val bin_shape_socket_domain : Bin_prot.Shape.t
type socket_type = Core.Unix.socket_type =
| SOCK_STREAM
| SOCK_DGRAM
| SOCK_RAW
| SOCK_SEQPACKET
include sig ... end
val socket_type_of_sexp : Sexplib.Sexp.t ‑> socket_type
val sexp_of_socket_type : socket_type ‑> Sexplib.Sexp.t
val bin_socket_type : socket_type Bin_prot.Type_class.t
val bin_read_socket_type : socket_type Bin_prot.Read.reader
val __bin_read_socket_type__ : (int ‑> socket_type) Bin_prot.Read.reader
val bin_reader_socket_type : socket_type Bin_prot.Type_class.reader
val bin_size_socket_type : socket_type Bin_prot.Size.sizer
val bin_write_socket_type : socket_type Bin_prot.Write.writer
val bin_writer_socket_type : socket_type Bin_prot.Type_class.writer
val bin_shape_socket_type : Bin_prot.Shape.t
type sockaddr = Core.Unix.sockaddr =
| ADDR_UNIX of string
| ADDR_INET of Inet_addr.t * int
include sig ... end
val sexp_of_sockaddr : sockaddr ‑> Sexplib.Sexp.t
val bin_sockaddr : sockaddr Bin_prot.Type_class.t
val bin_read_sockaddr : sockaddr Bin_prot.Read.reader
val __bin_read_sockaddr__ : (int ‑> sockaddr) Bin_prot.Read.reader
val bin_reader_sockaddr : sockaddr Bin_prot.Type_class.reader
val bin_size_sockaddr : sockaddr Bin_prot.Size.sizer
val bin_write_sockaddr : sockaddr Bin_prot.Write.writer
val bin_writer_sockaddr : sockaddr Bin_prot.Type_class.writer
val bin_shape_sockaddr : Bin_prot.Shape.t
val sockaddr_of_sexp : Core.Sexp.t ‑> sockaddr
type sockaddr_blocking_sexp = sockaddr

sockaddr_blocking_sexp is like sockaddr, with of_sexp that performs DNS lookup to resolve Inet_addr.t.

include sig ... end
val sockaddr_blocking_sexp_of_sexp : Sexplib.Sexp.t ‑> sockaddr_blocking_sexp
val sexp_of_sockaddr_blocking_sexp : sockaddr_blocking_sexp ‑> Sexplib.Sexp.t
val bin_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Type_class.t
val bin_read_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Read.reader
val __bin_read_sockaddr_blocking_sexp__ : (int ‑> sockaddr_blocking_sexp) Bin_prot.Read.reader
val bin_reader_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Type_class.reader
val bin_size_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Size.sizer
val bin_write_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Write.writer
val bin_writer_sockaddr_blocking_sexp : sockaddr_blocking_sexp Bin_prot.Type_class.writer
val bin_shape_sockaddr_blocking_sexp : Bin_prot.Shape.t
module Addr_info : sig ... end
module Name_info : sig ... end
val gethostname : unit ‑> string
val getuid : unit ‑> int
val geteuid : unit ‑> int
val getgid : unit ‑> int
val getegid : unit ‑> int
val setuid : int ‑> unit
module Error = Core.Unix.Error
type error = Core.Unix.Error.t =
| E2BIG
| EACCES
| EAGAIN
| EBADF
| EBUSY
| ECHILD
| EDEADLK
| EDOM
| EEXIST
| EFAULT
| EFBIG
| EINTR
| EINVAL
| EIO
| EISDIR
| EMFILE
| ENAMETOOLONG
| ENFILE
| ENODEV
| ENOENT
| ENOEXEC
| ENOLCK
| ENOMEM
| ENOSPC
| ENOSYS
| ENOTDIR
| ENOTEMPTY
| ENOTTY
| ENXIO
| EPERM
| EPIPE
| ERANGE
| EROFS
| ESPIPE
| ESRCH
| EXDEV
| EWOULDBLOCK
| EINPROGRESS
| EALREADY
| ENOTSOCK
| EDESTADDRREQ
| EMSGSIZE
| EPROTOTYPE
| ENOPROTOOPT
| EPROTONOSUPPORT
| ESOCKTNOSUPPORT
| EOPNOTSUPP
| EPFNOSUPPORT
| EAFNOSUPPORT
| EADDRINUSE
| EADDRNOTAVAIL
| ENETDOWN
| ENETUNREACH
| ENETRESET
| ECONNABORTED
| ECONNRESET
| ENOBUFS
| EISCONN
| ENOTCONN
| ESHUTDOWN
| ETOOMANYREFS
| ETIMEDOUT
| ECONNREFUSED
| EHOSTDOWN
| EHOSTUNREACH
| ELOOP
| EOVERFLOW
| EUNKNOWNERR of int
val sexp_of_error : Error.t ‑> Core.Sexp.t
val error_of_sexp : Core.Sexp.t ‑> Error.t
exception Unix_error of Error.t * string * string
module Terminal_io : sig ... end
module Passwd : sig ... end

Structure of entries in the passwd database.

module Group : sig ... end

Structure of entries in the groups database.

module Ifaddr = Core.Unix.Ifaddr
val getifaddrs : unit ‑> Ifaddr.t list Import.Deferred.t

getifaddrs gets the information using the socket-based netlink interface, which can block, see: https://www.infradead.org/~tgr/libnl/doc/core.html.

val getlogin : unit ‑> string Import.Deferred.t

Return the login name of the user executing the process.

This returns a deferred because the username may need to be looked up in what is essentially a database elsewhere on the network (winbound user, or NIS).

val wordexp : (?flags:[ `No_cmd | `Show_err | `Undef ] list ‑> string ‑> string array Import.Deferred.t) Core.Or_error.t