oneechanhax/phunix
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Convert a few man pages to mandoc

Browse Source
This commit is contained in:
Thomas Veerman 2010-07-15 08:48:24 +00:00
parent 8a0c10fcb9
commit 3404e8e4e5
3 changed files with 694 additions and 509 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

883
man/man2/intro.2
View File

@ -1,460 +1,583 @@
.\" Copyright (c) 1980,1983,1986 Regents of the University of California. .\" Copyright (c) 1980, 1983, 1986, 1991, 1993
.\" The Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement .\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution. .\" specifies the terms and conditions for redistribution.
.\" .\"
.\" @(#)intro.2 6.7 (Berkeley) 5/23/86 .\" @(#)intro.2 8.5 (Berkeley) 2/27/95
.\" .\"
.TH INTRO 2 "June 30, 1986" .\" Adapted to MINIX 3
.UC 4 .\"
.de en .Dd July 14, 2010
.HP .Dt INTRO 2
\\$1 \\$2 \\$3 .Os
.br .Sh NAME
.. .Nm intro ,
.SH NAME .Nm errno
intro, errno \- introduction to system calls and error numbers .Nd introduction to system calls and error numbers
.SH SYNOPSIS .Sh SYNOPSIS
.B "#include <errno.h>" .In errno.h
.SH DESCRIPTION .Sh DESCRIPTION
This section describes all of the system calls. Most This section provides an overview of the system calls,
of these calls have one or more error returns. their error returns, and other common definitions and concepts.
An error condition is indicated by an otherwise impossible return .Sh DIAGNOSTICS
value. This is almost always \-1; the individual descriptions Nearly all of the system calls provide an error number in the external
specify the details. variable
Note that a number of system calls overload the meanings of these .Va errno .
error numbers, and that the meanings must be interpreted according .Pp
to the type and circumstances of the call. When a system call detects an error,
.PP it returns an integer value
As with normal arguments, all return codes and values from indicating failure (usually \-1)
functions are of type integer unless otherwise noted. and sets the variable
An error number is also made available in the external .Va errno
variable \fBerrno\fP, which is not cleared accordingly.
on successful calls. (This allows interpretation of the failure on receiving
Thus \fBerrno\fP should be tested only after an error has occurred. a \-1 and to take action accordingly.)
.PP Successful calls never set
.Va errno ;
once set, it remains until another error occurs.
It should only be examined after an error has been reported, because
otherwise a leftover value from some previous error may be found
instead.
.Po
Many library functions that are not system calls also set
.Va errno
on return, in the same fashion.
In these cases a nonzero value may be left in
.Va errno
even upon successful return if some internal action failed.
.Pc
.Pp
The manual page for each system call will list some of the common
errno codes that system call can return, but that should not be
considered an exhaustive list, i.e.
a properly written program should be able to gracefully recover from
any error that a system call might return.
Documenting all the error codes that a system call can return in
a more specification-like manner would take more resources than
this project has available.
.Pp
Note also that a number of system calls overload the meanings of these
error numbers, and that in these cases the meanings must be
interpreted according to the type and circumstances of the call.
.Pp
The following is a list of the errors and their The following is a list of the errors and their
names as given in names as given in
.RI < sys/errno.h >: .In errno.h .
.en 0 OK "Error 0 .Bl -hang -width Ds
Unused. (The symbol "OK" is only used inside the kernel source.) .It Er 0 OK Em "Error 0" .
.en 1 EPERM "Not owner Not used. (The symbol "OK" is only used inside the kernel source.)
Typically this error indicates .It 1 EPERM Em "Operation not permitted" .
an attempt to modify a file in some way forbidden An attempt was made to perform an operation limited to processes
except to its owner or super-user. with appropriate privileges or to the owner of a file or other
It is also returned for attempts resources.
by ordinary users to do things .It Er 2 ENOENT Em "No such file or directory" .
allowed only to the super-user. A component of a specified pathname did not exist, or the
.en 2 ENOENT "No such file or directory pathname was an empty string.
This error occurs when a file name is specified .It Er 3 ESRCH Em "No such process" .
and the file should exist but doesn't, or when one No process could be found corresponding to that specified by the given
of the directories in a path name does not exist. process ID.
.en 3 ESRCH "No such process It Er 4 EINTR Em "Interrupted function call" .
The process or process group whose number was given An asynchronous signal (such as
does not exist, or any such process is already dead. .Dv SIGINT
.en 4 EINTR "Interrupted system call
An asynchronous signal (such as interrupt or quit)
that the user has elected to catch
occurred during a system call.
If execution is resumed
after processing the signal
and the system call is not restarted,
it will appear as if the interrupted system call
returned this error condition.
.en 5 EIO "I/O error
Some physical I/O error occurred during an I/O operation, usually
.B read
or or
.BR write . .Dv SIGQUIT )
Operations on file descriptors that refer to devices that are forcefully was caught by the process during the execution of an interruptible
taken away or in a bad state will also provoke this error. function.
.en 6 ENXIO "No such device or address If the signal handler performs a normal return, the
I/O on a special file refers to a subdevice that does not interrupted function call will seem to have returned the error condition.
exist, .It Er 5 EIO Em "Input/output error" .
or beyond the limits of the device. Some physical input or output error occurred.
It may also occur when, for example, an illegal tape drive This error will not be reported until a subsequent operation on the same file
unit number is selected descriptor and may be lost (over written) by any subsequent errors.
or a disk pack is not loaded on a drive. .It Er 6 ENXIO Em "Device not configured" .
.en 7 E2BIG "Arg list too long Input or output on a special file referred to a device that did not
An argument list longer than ARG_MAX bytes is presented to exist, or
.BR execve . made a request beyond the limits of the device.
ARG_MAX is set to 4096 bytes for 16-bit MINIX 3, 16384 bytes for 32-bit This error may also occur when, for example,
MINIX 3, and unlimited for Minix-vmd as these systems are released. a tape drive is not online or no disk pack is
.en 8 ENOEXEC "Exec format error loaded on a drive.
A request is made to execute a file .It Er 7 E2BIG Em "Arg list too long" .
The number of bytes used for the argument and environment
list of the new process exceeded the current limit of
262144 bytes
.Pf ( Dv ARG_MAX
in
.In limits.h ) .
.It Er 8 ENOEXEC Em "Exec format error" .
A request was made to execute a file
that, although it has the appropriate permissions, that, although it has the appropriate permissions,
does not start with a valid magic number, (see was not in the format required for an
.BR a.out (5)). executable file.
.en 9 EBADF "Bad file number .It Er 9 EBADF Em "Bad file descriptor" .
Either a file descriptor refers to no A file descriptor argument was out of range, referred to no open file,
open file, or a
or a read (resp. write) request is made to .Xr read 2
a file that is open only for writing (resp. reading). (or
.en 10 ECHILD "No children .Xr write 2 )
.B Wait request was made to a file that was
and the process has no only open for writing (or reading).
living or unwaited-for children. .It Er 10 ECHILD Em "\&No child processes" .
.en 11 EAGAIN "Resource temporarily unavailable A
In a .Xr wait 2
.B fork,
the system's process table is full or the user is not allowed to create
any more processes, otherwise an operation that would cause a process to
block was attempted on an object in non-blocking mode (see \fBfcntl\fP(2)).
.en 12 ENOMEM "Not enough core
During an
.B execve
or or
.B brk, .Xr waitpid 2
a program asks for more (virtual) memory than the system is function was executed by a process that had no existing or unwaited-for
able to supply, child processes.
or a process size limit would be exceeded. .It Er 11 EAGAIN Em "Resource temporarily unavailable" .
The maximum size This is a temporary condition and later calls to the
of the data+stack segment is set by the same routine may complete normally.
.BR chmem (1) .It Er 12 ENOMEM Em "Cannot allocate memory" .
program. For Minix-vmd a small data+stack size is increased to 3 megabytes The new process image required more memory than was allowed by the hardware
when a program is executed. or by system-imposed memory management constraints.
.en 13 EACCES "Permission denied Soft limits may be increased to their corresponding hard limits.
.It Er 13 EACCES Em "Permission denied" .
An attempt was made to access a file in a way forbidden An attempt was made to access a file in a way forbidden
by the protection system. Also an attempt to open a device for writing by its file access permissions.
that is physically write protected. .It Er 14 EFAULT Em "Bad address" .
.en 14 EFAULT "Bad address The system detected an invalid address in attempting to
An argument of a system call is outside the address space allocated to a use an argument of a call.
process. The reliable detection of this error cannot be guaranteed and when not detected
.en 15 ENOTBLK "Block device required may result in the generation of a signal, indicating an address violation,
A plain file was mentioned where a block device was required, which is sent to the process.
e.g., in .It Er 15 ENOTBLK Em "Block device required" .
.BR mount . A block device operation was attempted on a non-block device or file.
.en 16 EBUSY "Resource busy .It Er 16 EBUSY Em "Resource busy" .
An attempt to mount a device that was already mounted or An attempt to use a system resource which was in use at the time
an attempt was made to dismount a device in a manner which would have conflicted with the request.
on which there is an active file .It Er 17 EEXIST Em "File exists" .
(open file, current directory, mounted-on file, or active text segment).
A request was made to an exclusive access device that was already in use.
.en 17 EEXIST "File exists
An existing file was mentioned in an inappropriate context, An existing file was mentioned in an inappropriate context,
e.g., for instance, as the new link name in a
.BR link . .Xr link 2
.en 18 EXDEV "Cross-device link function.
A hard link to a file on another device .It Er 18 EXDEV Em "Improper link" .
A hard link to a file on another file system
was attempted. was attempted.
.en 19 ENODEV "No such device .It Er 19 ENODEV Em "Operation not supported by device" .
An attempt was made to access a device that is not configured by the system, An attempt was made to apply an inappropriate
i.e., there is no driver for the device. function to a device,
.en 20 ENOTDIR "Not a directory for example,
A non-directory was specified where a directory trying to read a write-only device such as a printer.
is required, .It Er 20 ENOTDIR Em "Not a directory" .
for example, in a path name or A component of the specified pathname existed, but it was
as an argument to not a directory, when a directory was expected.
.BR chdir . .It Er 21 EISDIR Em "Is a directory" .
.en 21 EISDIR "Is a directory An attempt was made to open a directory with write mode specified.
An attempt to write on a directory. .It Er 22 EINVAL Em "Invalid argument" .
.en 22 EINVAL "Invalid argument Some invalid argument was supplied.
Some invalid argument: (For example, specifying an undefined signal to a
dismounting a non-mounted .Xr signal 3
device, or
mentioning an unknown signal in .Xr kill 2
.B signal, function).
or some other argument inappropriate for the call. .It Er 23 ENFILE Em "Too many open files in system" .
Also set by math functions, (see Maximum number of file descriptors allowable on the system
.BR math (3)). has been reached and a requests for an open cannot be satisfied
.en 23 ENFILE "File table overflow until at least one has been closed.
The system's table of open files is full, .It Er 24 EMFILE Em "Too many open files" .
and temporarily no more \*[Lt]As released, the limit on the number of
.I opens open files per process is 64.\*[Gt]
can be accepted. The
.en 24 EMFILE "Too many open files .Xr getrlimit 2
The limit on the number of open files per process, OPEN_MAX, is reached. call with the
As released, this limit is 20 for MINIX 3, and 30 for Minix-vmd. .Ar RLIMIT_NOFILE
.en 25 ENOTTY "Not a typewriter resource will obtain the current limit.
The file mentioned in an .It Er 25 ENOTTY Em "Inappropriate ioctl for device" .
.B ioctl A control function (see
is not a terminal or one of the .Xr ioctl 2 )
devices to which this call applies. (Often seen error from programs with was attempted for a file or
bugs in their error reporting code.) special device for which the operation was inappropriate.
.en 26 ETXTBSY "Text file busy .en 26 ETXTBSY "Text file busy
Attempt to execute a program that is open for writing. Obsolete under MINIX 3. Attempt to execute a program that is open for writing. Obsolete under MINIX 3.
.en 27 EFBIG "File too large .It Er 27 EFBIG Em "File too large" .
The size of a file exceeded the maximum (little over 64 megabytes for The size of a file exceeded the maximum.
the V2 file system). (The system-wide maximum file size is
.en 28 ENOSPC "No space left on device 2147483648 (2GB) bytes.
Each file system may impose a lower limit for files contained within it).
.It Er 28 ENOSPC Em "Device out of space" .
A A
.B write .Xr write 2
to an ordinary file, the creation of a to an ordinary file, the creation of a
directory or symbolic link, or the creation of a directory directory or symbolic link, or the creation of a directory
entry failed because no more disk blocks are available entry failed because no more disk blocks were available
on the file system, or the allocation of an inode for a newly on the file system, or the allocation of an inode for a newly
created file failed because no more inodes are available created file failed because no more inodes were available
on the file system. on the file system.
.en 29 ESPIPE "Illegal seek .It Er 29 ESPIPE Em "Illegal seek" .
An An
.B lseek .Xr lseek 2
was issued to a pipe or TCP/IP channel. function was issued on a socket, pipe or
This error may also be issued for .Tn FIFO .
other non-seekable devices. .It Er 30 EROFS Em "Read-only file system" .
.en 30 EROFS "Read-only file system An attempt was made to modify a file or directory
An attempt to modify a file or directory
was made was made
on a device mounted read-only. on a file system that was read-only at the time.
.en 31 EMLINK "Too many links .It Er 31 EMLINK Em "Too many links" .
An attempt to make more than a certain number of hard links to a file. The The number of hard links to a single file has exceeded the maximum.
advertized maximum, LINK_MAX, is 127, but Minix-vmd uses a much larger (The system-wide maximum number of hard links is 32767.
maximum of 32767 for the V2 file system. Each file system may impose a lower limit for files contained within it).
.en 32 EPIPE "Broken pipe .It Er 32 EPIPE Em "Broken pipe" .
A write on a pipe or TCP/IP channel for which there is no process A write on a pipe, socket or
.Tn FIFO
for which there is no process
to read the data. to read the data.
This condition normally generates the signal SIGPIPE; .It Er 33 EDOM Em "Numerical argument out of domain" .
the error is returned if the signal is caught or ignored. A numerical input argument was outside the defined domain of the mathematical
.en 33 EDOM "Math argument function.
The argument of a function in the math package .It Er 34 ERANGE Em "Result too large or too small" .
is out of the domain of the function. The result of the function is too large or too small to be represented
.en 34 ERANGE "Result too large in the available space.
The value of a function in the math package .It Er 35 EDEADLK Em "Resource deadlock avoided" .
is unrepresentable within machine precision. An attempt was made to lock a system resource that
.en 35 EDEADLK "Resource deadlock avoided would have resulted in a deadlock situation.
A process attempts to place a blocking lock on a file that is already .It Er 36 ENAMETOOLONG Em "File name too long" .
locked by another process and that process is waiting for the first A component of a path name exceeded
process to unlock a file that first process already has a lock on. .Pq Dv NAME_MAX
(The classic "lock A, lock B" by process 1, and "lock B, lock A" by characters, or an entire
process 2.) path name exceeded 255
.en 36 ENAMETOOLONG "File name too long" .Pq Dv PATH_MAX
The path name exceeds PATH_MAX characters. PATH_MAX equals 255 as characters.
distributed. .It Er 37 ENOLCK Em "No locks available" .
.en 37 ENOLCK "No locks available A system-imposed limit on the number of simultaneous file
The system's table of active locks is full. locks was reached.
.en 38 ENOSYS "Function not implemented .It Er 38 ENOSYS Em "Function not implemented" .
The system call is not supported. Either an old program uses an obsolete Attempted a system call that is not available on this
call, or a program for a more capable system is run on a less capable
system. system.
.en 39 ENOTEMPTY "Directory not empty" .It Er 39 ENOTEMPTY Em "Directory not empty" .
A directory with entries other than \*(lq.\*(rq and \*(lq..\*(rq A directory with entries other than
.Ql \&.
and
.Ql \&..
was supplied to a remove directory or rename call. was supplied to a remove directory or rename call.
.en 40 ELOOP "Too many symbolic links" .It Er 40 ELOOP Em "Too many levels of symbolic links" .
A path name lookup involved too many symbolic links. A path name lookup involved more than 16
.en 41 ERESTART "Service restarted .Pq Dv SYMLOOP_MAX
.en 43 EIDRM "Identifier removed symbolic links.
.en 44 EILSEQ "Illegal byte sequence .It Er 41 ERESTART Em "Service restarted" .
.en 45 EFTYPE "Wrong file format or type .It Er 43 ERESTART Em "Identifier removed" .
.en 50 EPACKSIZE "Invalid packet size An IPC identifier was removed while the current process was waiting on it.
.en 51 ENOBUFS "Not enough buffers left .It Er 44 EILSEQ Em "Illegal byte sequence" .
.en 52 EBADIOCTL "Illegal ioctl for device A wide character/multibyte character encoding error occurred.
.en 53 EBADMODE "Bad mode in ioctl .It Er 45 EFTYPE Em "Inappropriate file type or format" .
.en 54 EWOULDBLOCK "Would block Attempted a file operation on a file of a type for which it was invalid.
.en 55 ENETUNREACH "Network unreachable .It Er 50 EPACKSIZE Em "Invalid packet size" .
.en 56 EHOSTUNREACH "Host unreachable .It Er 51 ENOBUFS Em "\&No buffer space available" .
.en 57 EISCONN "Already connected An operation on a socket or pipe was not performed because
.en 58 EADDRINUSE "Address in use the system lacked sufficient buffer space or because a queue was full.
.en 59 ECONNREFUSED "Connection refused .It Er 52 EBADIOCTL Em "Illegal ioctl for device" .
.en 60 ECONNRESET "Connection reset .It Er 53 EBADMODE Em "Bad mode in ioctl" .
.en 61 ETIMEDOUT "Connection timed out .It Er 54 EWOULDBLOCK Em "Would block" .
.en 62 EURG "Urgent data present .It Er 55 ENETUNREACH Em "Network is unreachable" .
.en 63 ENOURG "No urgent data present A socket operation was attempted to an unreachable network.
.en 64 ENOTCONN "No connection .It Er 56 EHOSTUNREACH Em "No route to host" .
.en 65 ESHUTDOWN "Already shutdown A socket operation was attempted to an unreachable host.
.en 66 ENOCONN "No such connection .It Er 57 EISCONN Em "Socket is already connected" .
.en 67 EAFNOSUPPORT "Address family not supported A
.en 68 EPROTONOSUPPORT "Protocol not supported by AF .Xr connect 2
.en 69 EPROTOTYPE "Protocol wrong type for socket request was made on an already connected socket; or,
.en 70 EINPROGRESS "Operation now in progress a
.en 71 EADDRNOTAVAIL "Can't assign requested address .Xr sendto 2
.en 72 EALREADY "Operation already in progress or
.en 73 EMSGSIZE "Message too long .Xr sendmsg 2
.en 74 ENOTSOCK "Socket operation on non-socket request on a connected socket specified a destination
.en 75 ENOPROTOOPT "Protocol not available when already connected.
.en 76 EOPNOTSUPP "Operation not supported (has alias ENOTSUP) .It Er 58 EADDRINUSE Em "Address already in use" .
.en 77 ENETDOWN "Network is down Only one usage of each address is normally permitted.
.ig .It Er 59 ECONNREFUSED Em "Connection refused" .
.en XXX EDQUOT "Disc quota exceeded" No connection could be made because the target machine actively
A refused it.
.B write This usually results from trying to connect
to an ordinary file, the creation of a to a service that is inactive on the foreign host.
directory or symbolic link, or the creation of a directory .It Er 60 ECONNRESET Em "Connection reset by peer" .
entry failed because the user's quota of disk blocks was A connection was forcibly closed by a peer.
exhausted, or the allocation of an inode for a newly This normally results from a loss of the connection on the remote
created file failed because the user's quota of inodes socket due to a timeout or a reboot.
was exhausted. .It Er 61 ETIMEDOUT Em "Operation timed out" .
.en XXX ESTALE "Stale NFS file handle" A
A client referenced a an open file, when the file has been deleted. .Xr connect 2
.en XXX EREMOTE "Too many levels of remote in path" or
An attempt was made to remotely mount a file system into a path which .Xr send 2
already has a remotely mounted component. request failed because the connected party did not
.. properly respond after a period of time.
.SH DEFINITIONS (The timeout period is dependent on the communication protocol).
.TP 5 .It Er 62 EURG Em "Urgent data present" .
Process ID .It Er 63 ENOURG Em "No urgent data present" .
.br .It Er 64 ENOTCONN Em "Socket is not connected" .
An request to send or receive data was disallowed because
the socket was not connected and (when sending on a datagram socket)
no address was supplied.
.It Er 65 ESHUTDOWN Em "Cannot send after socket shutdown" .
A request to send data was disallowed because the socket
had already been shut down with a previous
.Xr shutdown 2
call.
.It Er 66 ENOCONN Em "No such connection" .
.It Er 67 EAFNOSUPPORT Em "Address family not supported by protocol family" .
An address incompatible with the requested protocol was used.
For example, you shouldn't necessarily expect to be able to use
.Tn NS
addresses with
.Tn ARPA
Internet protocols.
.It Er 68 EPROTONOSUPPORT Em "Protocol not supported" .
The protocol has not been configured into the
system or no implementation for it exists.
.It Er 69 EPROTOTYPE Em "Protocol wrong type for socket" .
A protocol was specified that does not support the semantics of the
socket type requested.
For example, you cannot use the
.Tn ARPA
Internet
.Tn UDP
protocol with type
.Dv SOCK_STREAM .
.It Er 70 EINPROGRESS Em "Operation now in progress" .
An operation that takes a long time to complete (such as
a
.Xr connect 2 )
was attempted on a non-blocking object (see
.Xr fcntl 2 ) .
.It Er 71 EADDRNOTAVAIL Em "Cannot assign requested address" .
Normally results from an attempt to create a socket with an
address not on this machine.
.It Er 72 EALREADY Em "Operation already in progress" .
An operation was attempted on a non-blocking object that already
had an operation in progress.
.It Er 73 EMSGSIZE Em "Message too long" .
A message sent on a socket was larger than the internal message buffer
or some other network limit.
.It Er 74 ENOTSOCK Em "Socket operation on non-socket" .
Self-explanatory.
.It Er 75 ENOPROTOOPT Em "Protocol option not available" .
A bad option or level was specified in a
.Xr getsockopt 2
or
.Xr setsockopt 2
call.
.It Er 76 EOPNOTSUPP Em "Operation not supported" (has alias ENOTSUP) .
The attempted operation is not supported for the type of object referenced.
Usually this occurs when a file descriptor refers to a file or socket
that cannot support this operation,
for example, trying to
.Em accept
a connection on a datagram socket.
.It Er 77 ENETDOWN Em "Network is down" .
A socket operation encountered a dead network.
.El
.Sh DEFINITIONS
.Bl -tag -width Ds
.It Process ID
Each active process in the system is uniquely identified by a positive Each active process in the system is uniquely identified by a positive
integer called a process ID. The range of this ID is from 1 to 29999. integer called a process ID. The range of this ID is from 1 to 29999.
The special process with process ID 1 is .It Parent process ID
.BR init ,
the ancestor of all processes.
.TP 5
Parent process ID
.br
A new process is created by a currently active process; (see A new process is created by a currently active process; (see
.BR fork (2)). .Xr fork 2 ) .
The parent process ID of a process is the process ID of its creator, The parent process ID of a process is initially the process ID of its creator.
unless the creator dies, then If the creating process exits,
.B init the parent process ID of each child is set to the ID of
becomes the parent of the orphaned process. .Em init ,
.TP 5 .Xr init 8 .
Process Group ID .It Process Group
.br
Each active process is a member of a process group that is identified by Each active process is a member of a process group that is identified by
a positive integer called the process group ID. This is the process a positive integer called the process group ID.
ID of the group leader. This grouping permits the signaling of related This is the process ID of the group leader.
processes (see This grouping permits the signaling of related processes (see
.BR kill (2)). .Xr termios 4 ).
.TP 5 .It Session
Real User ID and Real Group ID A session is a set of one or more process groups.
.br A session is created by a successful call to
.Xr setsid 2 ,
which causes the caller to become the only member of the only process
group in the new session.
.It Session leader
A process that has created a new session by a successful call to
.Xr setsid 2 ,
is known as a session leader.
Only a session leader may acquire a terminal as its controlling terminal (see
.Xr termios 4 ) .
.It Controlling process
A session leader with a controlling terminal is a controlling process.
.It Controlling terminal
A terminal that is associated with a session is known as the controlling
terminal for that session and its members.
.It "Real User ID and Real Group ID"
Each user on the system is identified by a positive integer Each user on the system is identified by a positive integer
termed the real user ID. termed the real user ID.
.IP .Pp
Each user is also a member of one or more groups. Each user is also a member of one or more groups.
One of these groups is distinguished from others and One of these groups is distinguished from others and
used in implementing accounting facilities. The positive used in implementing accounting facilities.
integer corresponding to this distinguished group is termed The positive integer corresponding to this distinguished group is
the real group ID. termed the real group ID.
(Under standard MINIX 3 this is the only group a process can be a member of.) .Pp
.IP
All processes have a real user ID and real group ID. All processes have a real user ID and real group ID.
These are initialized from the equivalent attributes These are initialized from the equivalent attributes
of the process that created it. of the process that created it.
.TP 5 .It "Effective User Id, Effective Group Id, and Group Access List"
Effective User Id, Effective Group Id, and Access Groups Access to system resources is governed by two values:
.br the effective user ID and the group access list.
Access to system resources is governed by three values: (In POSIX.1, the group access list is known as the set of supplementary
the effective user ID, the effective group ID, and the group IDs, and it is unspecified whether the effective group ID is
group access list. a member of the list.)
.IP .Pp
The effective user ID and effective group ID are initially the The effective user ID and effective group ID are initially the
process's real user ID and real group ID respectively. Either process's real user ID and real group ID respectively. Either
may be modified through execution of a set-user-ID or set-group-ID may be modified through execution of a set-user-ID or set-group-ID
file (possibly by one its ancestors) (see file (possibly by one its ancestors) (see
.BR execve (2)). .BR execve (2)).
.IP .Pp
The group access list is an additional set of group ID's The group access list is an additional set of group ID's
used only in determining resource accessibility. Access checks used only in determining resource accessibility.
are performed as described below in ``File Access Permissions''. Access checks are performed as described below in
The maximum number of additional group ID's is NGROUPS_MAX. .Qq File Access Permissions .
For MINIX 3 this is 0, but Minix-vmd supports a list of up to 16 It Super-user
additional group ID's. (Also known as ``supplemental'' group ID's.)
.TP 5
Super-user
.br
A process is recognized as a A process is recognized as a
.I super-user .Em super-user
process and is granted special privileges if its effective user ID is 0. process and is granted special privileges if its effective user ID is 0.
.TP 5 .It Descriptor
Descriptor An integer assigned by the system when a file is referenced
.br
An integer assigned by the system when a file or device is referenced
by by
.BR open (2), .Xr open 2
.BR dup (2)
or or
.BR fcntl (2) .Xr dup 2 ,
which uniquely identifies an access path to that file or device from or when a socket is created by
.Xr pipe 2 ,
.Xr socket 2 ,
or
.Xr socketpair 2 ,
which uniquely identifies an access path to that file or socket from
a given process or any of its children. a given process or any of its children.
.TP 5 .It File Name
File Descriptor Names consisting of up to 60
Older, and often used name for a descriptor. .Pq Dv NAME_MAX
.TP 5 characters may be used to name
File Name an ordinary file, special file, or directory.
.br .Pp
Names consisting of up to NAME_MAX characters may be used to name These characters may be selected from the set of all
an ordinary file, special file, or directory. NAME_MAX is the maximum .Tn ASCII
of the maximum file name lengths of the supported file systems. character
Excess characters are ignored when too long file names are used for excluding 0 (NUL) and the
files in a given file system. .Tn ASCII
The maximum file name length of the V1 and V2 file systems code for
is 14 characters. The Minix-vmd "flex" variants of V1 and V2 have a .Ql \&/
60 character maximum. (slash).
.IP (The parity bit, bit 7, must be 0).
The characters in a file name may assume any value representable in .Pp
eight bits excluding 0 (null) and the ASCII code for / (slash). Note that it is generally unwise to use
.IP .Ql \&* ,
Note that it is generally unwise to use one of \e'"<>();~$^&*|{}[]? .Ql \&? ,
as part of file names because of the special meaning attached to these .Ql \&[
characters by the shell. or
.TP 5 .Ql \&]
Path Name as part of
.br file names because of the special meaning attached to these characters
A path name is a null-terminated character string starting with an by the shell.
optional slash (/), followed by zero or more directory names separated .It Pathname
A path name is a
.Tn NUL Ns -terminated
character string starting with an
optional slash
.Ql \&/ ,
followed by zero or more directory names separated
by slashes, optionally followed by a file name. by slashes, optionally followed by a file name.
The total length of a path name must be less than PATH_MAX characters The total length of a path name must be less than 255
(255 as distributed.) .Pq Dv PATH_MAX
.IP characters.
.Pp
If a path name begins with a slash, the path search begins at the If a path name begins with a slash, the path search begins at the
.I root .Em root
directory. directory.
Otherwise, the search begins from the current working directory. Otherwise, the search begins from the current working directory.
A slash by itself names the root directory. A null pathname is A slash by itself names the root directory.
illegal, use "." to refer to the current working directory. An empty string is not a valid pathname.
.TP 5 .It Directory
Directory
.br
A directory is a special type of file that contains entries A directory is a special type of file that contains entries
that are references to other files. that are references to other files.
Directory entries are called links. By convention, a directory Directory entries are called links.
contains at least two links, . and .., referred to as By convention, a directory contains at least two links,
.I dot .Ql \&.
and and
.I dot-dot .Ql \&.. ,
respectively. Dot refers to the directory itself and referred to as
dot-dot refers to its parent directory. .Em dot
.TP 5 and
Root Directory and Current Working Directory .Em dot-dot
.br respectively.
Dot refers to the directory itself and dot-dot refers to its parent directory.
.It "Root Directory and Current Working Directory"
Each process has associated with it a concept of a root directory Each process has associated with it a concept of a root directory
and a current working directory for the purpose of resolving path and a current working directory for the purpose of resolving path
name searches. A process's root directory need not be the root name searches.
A process's root directory need not be the root
directory of the root file system. directory of the root file system.
.TP 5 .It File Access Permissions
File Access Permissions
.br
Every file in the file system has a set of access permissions. Every file in the file system has a set of access permissions.
These permissions are used in determining whether a process These permissions are used in determining whether a process
may perform a requested operation on the file (such as opening may perform a requested operation on the file (such as opening
a file for writing). Access permissions are established at the a file for writing).
time a file is created. They may be changed at some later time Access permissions are established at the time a file is created.
through the They may be changed at some later time through the
.BR chmod (2) .Xr chmod 2
call. call.
.IP .Pp
File access is broken down according to whether a file may be: read, File access is broken down according to whether a file may be: read,
written, or executed. Directory files use the execute written, or executed.
permission to control if the directory may be searched. Directory files use the execute permission to control if the
.IP directory may be searched.
.Pp
File access permissions are interpreted by the system as File access permissions are interpreted by the system as
they apply to three different classes of users: the owner they apply to three different classes of users: the owner
of the file, those users in the file's group, anyone else. of the file, those users in the file's group, anyone else.
Every file has an independent set of access permissions for Every file has an independent set of access permissions for
each of these classes. When an access check is made, the system each of these classes.
decides if permission should be granted by checking the access When an access check is made, the system decides if permission should be
information applicable to the caller. granted by checking the access information applicable to the caller.
.IP .Pp
Read, write, and execute/search permissions on Read, write, and execute/search permissions on
a file are granted to a process if: a file are granted to a process if:
.IP .Pp
The process's effective user ID is that of the super-user. The process's effective user ID is that of the super-user.
.IP (Note: even the super-user cannot execute a non-executable file).
.Pp
The process's effective user ID matches the user ID of the owner The process's effective user ID matches the user ID of the owner
of the file and the owner permissions allow the access. of the file and the owner permissions allow the access.
.IP .Pp
The process's effective user ID does not match the user ID of the The process's effective user ID does not match the user ID of the
owner of the file, and either the process's effective owner of the file, and either the process's effective
group ID matches the group ID group ID matches the group ID
of the file, or the group ID of the file is in of the file, or the group ID of the file is in
the process's group access list, the process's group access list,
and the group permissions allow the access. and the group permissions allow the access.
.IP .Pp
Neither the effective user ID nor effective group ID Neither the effective user ID nor effective group ID
and group access list of the process and group access list of the process
match the corresponding user ID and group ID of the file, match the corresponding user ID and group ID of the file,
but the permissions for ``other users'' allow access. but the permissions for ``other users'' allow access.
.IP .Pp
Otherwise, permission is denied. Otherwise, permission is denied.
.SH SEE ALSO .It Sockets and Address Families
.BR intro (3), A socket is an endpoint for communication between processes.
.BR strerror (3). Each socket has queues for sending and receiving data.
.Pp
Sockets are typed according to their communications properties.
These properties include whether messages sent and received
at a socket require the name of the partner, whether communication
is reliable, the format used in naming message recipients, etc.
.Pp
Each instance of the system supports some
collection of socket types; consult
.Xr socket 2
for more information about the types available and
their properties.
.Pp
Each instance of the system supports some number of sets of
communications protocols.
Each protocol set supports addresses of a certain format.
An Address Family is the set of addresses for a specific group of protocols.
Each socket has an address
chosen from the address family in which the socket was created.
.El
.Sh SEE ALSO
.Xr intro 3 ,
.Xr perror 3

184
man/man3/getcontext.3
View File

@ -1,96 +1,136 @@
.TH GETCONTEXT 3 "Mar 2, 2010" .Dd Mar 2, 2010
.SH NAME .Dt GETCONTEXT 3
getcontext, setcontext \- get and set current user context .Os
.SH SYNOPSIS .Sh NAME
.nf .Nm getcontext ,
.ft B .Nm setcontext
#include <ucontext.h> .Nd get and set current user context
.Sh LIBRARY
int getcontext(ucontext\_t *\fIucp\fP) .Lb libc
int setcontext(const ucontext\_t *\fIoucp\fP) .Sh SYNOPSIS
.SH DESCRIPTION .In ucontext.h
.Ft int
.Fn getcontext "ucontext_t *ucp"
.Ft int
.Fn setcontext "const ucontext_t *ucp"
.Sh DESCRIPTION
The The
.BR makecontext (3) .Xr makecontext 3
, ,
.BR swapcontext (3) .Xr swapcontext 3
, ,
.BR getcontext (3) .Xr getcontext 3
, and , and
.BR setcontext (3) .Xr setcontext 3
together form a set of functions that allow user-level context switching between multiple threads of control within a process. together form a set of functions that allow user-level context switching between multiple threads of control within a process.
.PP .Pp
The \fIucontext_t\fP type is a structure that has at least the following members: The
.in +4 .Vt ucontext_t
.nf type is a structure that has at least the following members:
.Bd -offset 4n -literal
typedef struct __ucontext { typedef struct __ucontext {
ucontext_t *uc_link; ucontext_t *uc_link;
sigset_t uc_sigmask; sigset_t uc_sigmask;
stack_t uc_stack; stack_t uc_stack;
mcontext_t uc_mcontext; mcontext_t uc_mcontext;
... ...
} ucontext_t; } ucontext_t;
.Ed
.fi with
.in .Vt sigset_t
with \fIsigset_t\fP and \fIstack_t\fP defined in and
.IR <signal.h> . .Vt stack_t
Here \fIuc_link\fP points to the context that will be resumed when the current context returns (if \fIuc_link\fP is NULL, the process exits), \fIsigset_t\fP is the set of signals blocks in this context, \fIuc_stack\fP is the stack used by this context (when the context was modified by defined in
.BR makecontext (3)), .In signal.h .
and \fIuc_mcontext\fP is the machine-specific representation of the saved context. The \fImcontext_t\fP type is machine-dependent and opaque. Here
.PP .Va uc_link
MINIX 3 has an additional \fIuc_flags\fP member that supports the following flags: points to the context that will be resumed when the current context returns (if
.PP .Va uc_link
.in +2 is NULL, the process exits),
.nf .Va uc_sigmask
is the set of signals blocked in this context,
.Va uc_stack
is the stack used by this context (when the context was modified by
.Xr makecontext 3 ),
and
.Va uc_mcontext
is the machine-specific representation of the saved context. The
.Vt mcontext_t
type is machine-dependent and opaque.
.Pp
MINIX 3 has an additional
.Va uc_flags
member that supports the following flags:
.Pp
.Bd -offset 4n -literal
UCF_IGNSIGM /* Current signal mask is not stored or restored */ UCF_IGNSIGM /* Current signal mask is not stored or restored */
UCF_IGNFPU /* FPU state is not stored or restored for this context */ UCF_IGNFPU /* FPU state is not stored or restored for this context */
.fi .Ed
.in .Pp
.PP
Not storing and restoring the signal mask and/or FPU state speeds up context switching considerably. Not storing and restoring the signal mask and/or FPU state speeds up context switching considerably.
.PP .Pp
The The
.BR getcontext () .Fn getcontext
function initializes the structure pointed to by \fIucp\fP to the current user context of the calling thread. function initializes the structure pointed to by
.PP .Va ucp
to the current user context of the calling thread.
.Pp
The The
.BR setcontext () .Fn setcontext
function restores the user context pointed to by \fIucp\fP. A succesful call does not return; program execution resumes at the point specified by the \fIucp\fP argument passed to function restores the user context pointed to by
.BR setcontext (). .Va ucp .
The \fIucp\fP argument should be created either by a prior call to A succesful call does not return; program execution resumes at the point specified by the
.BR getcontext () .Va ucp
argument passed to
.Fn setcontext .
The
.Va ucp
argument should be created either by a prior call to
.Fn getcontext
or or
.BR makecontext (). .Fn makecontext .
If the \fIucp\fP argument was created with If the
.BR getcontext (), .Va ucp
argument was created with
.Fn getcontext ,
program execution continues as if the corresponding call of program execution continues as if the corresponding call of
.BR getcontext () .Fn getcontext
had just returned. If the \fIucp\fP argument was created with had just returned. If the
.BR makecontext (), .Va ucp
argument was created with
.Fn makecontext ,
program execution continues with the function passed to program execution continues with the function passed to
.BR makecontext (). .Fn makecontext .
.SH "RETURN VALUE" .Sh RETURN VALUES
When successful, When successful,
.BR getcontext () .Fn getcontext
returns 0 and returns 0 and
.BR setcontext () .Fn setcontext
does not return. Otherwise, both return -1 and does not return. Otherwise, both return -1 and
.I errno .Va errno
is set to indicate the error. is set to indicate the error.
.SH "ERRORS" .Sh ERRORS
.TP 15 .Bl -tag -width Er
[EINVAL] .It Bq Er EINVAL
The context is not properly initialized. The context is not properly initialized.
.TP 15 .It Bq Er EFAULT
[EFAULT] .Va ucp
\fIucp\fP is a NULL pointer. is a NULL pointer.
.El
.SH "SEE ALSO" .Sh SEE ALSO
.BR makecontext (3). .Xr makecontext 3 ,
.Xr swapcontext 3
.SH "AUTHORS" .Sh STANDARDS
The
.Fn getcontext ,
and
.Fn setcontext
functions conform to
.St -xsh5
and
.St -p1003.1-2001 .
.Sh AUTHORS
Thomas Veerman Thomas Veerman

136
man/man3/makecontext.3
View File

@ -1,75 +1,97 @@
.TH MAKECONTEXT 3 "Mar 2, 2010" .Dd Mar 2, 2010
.SH NAME .Dt MAKECONTEXT 3
makecontext, swapcontext \- manipulate user contexts .Os
.SH SYNOPSIS .Sh NAME
.nf .Nm makecontext ,
.ft B .Nm swapcontext
#include <ucontext.h> .Nd manipulate user contexts
.Sh LIBRARY
void makecontext(ucontext\_t *\fIucp\fP, void \fI(*func)(void)\fP, int \fIargc\fP, ...) .Lb libc
int swapcontext(ucontext\_t *\fIoucp\fP, const ucontext\_t *\fIucp\fP) .Sh SYNOPSIS
.SH DESCRIPTION .In ucontext.h
.Ft void
.Fn makecontext "ucontext_t *ucp" "void (*func)(void)" "int argc" ...
.Ft int
.Fn swapcontext "ucontext_t *oucp" "const ucontext_t *ucp"
.Sh DESCRIPTION
The The
.BR makecontext (3) .Xr makecontext 3 ,
, .Xr swapcontext 3 ,
.BR swapcontext (3) .Xr getcontext 3 ,
, and
.BR getcontext (3) .Xr setcontext 3
, and
.BR setcontext (3)
together form a set of functions that allow user-level context switching between multiple threads of control within a process. together form a set of functions that allow user-level context switching between multiple threads of control within a process.
.PP .Pp
The The
.BR makecontext () .Fn makecontext
function modifies the user thread pointed to by function modifies the user thread pointed to by
.I ucp .Va ucp
to continue execution by invoking function to continue execution by invoking function
.I func .Va func
and passing that function a number of and passing that function a number of
.I argc .Va argc
integer arguments. The value of integer arguments. The value of
.I argc .Va argc
must match the number of integer arguments passed to must match the number of integer arguments passed to
.I func .Va func ,
, otherwise the behavior is undefined. Context otherwise the behavior is undefined. Context
.I ucp .Va ucp
must have been initialized by a call to must have been initialized by a call to
.BR getcontext (3) .Xr getcontext 3
and have a stack allocated for it. The address of the stack must be assigned to \fIucp\->uc_stack.ss_sp\fP and the size of the stack to \fIucp\->uc_stack.ss_size\fP. The \fIucp\->uc_link\fP member is used to determine which successor context is run after the context modified by and have a stack allocated for it. The address of the stack must be assigned to
.BR makecontext () .Va ucp->uc_stack.ss_sp
returns. If left NULL, the process exits. and the size of the stack to
.PP .Va ucp->uc_stack.ss_size .
The The
.BR swapcontext () .Va ucp->uc_link
member is used to determine which successor context is run after the context modified by
.Fn makecontext
returns. If left NULL, the process exits.
.Pp
The
.Fn swapcontext
function saves the current context in the context structure pointed to by function saves the current context in the context structure pointed to by
.I oucp .Va oucp
and sets the context to the context structure pointed to by \fIucp\fP. and sets the context to the context structure pointed to by
.Va ucp .
.SH "RETURN VALUE" .Sh RETURN VALUES
When successful, When successful,
.BR swapcontext () .Fn swapcontext
returns 0. Otherwise, -1 is returned and returns 0. Otherwise, -1 is returned and
.I errno .Va errno
is set to indicate the error. Note that a successful call to is set to indicate the error. Note that a successful call to
.BR swapcontext () .Fn swapcontext
actually does not return. Only after returning to the context that called actually does not return. Only after returning to the context that called
.BR swapcontext () .Fn swapcontext ,
, it appears as if it appears as if
.BR swapcontext () .Fn swapcontext
returned 0. returned 0.
.Sh ERRORS
.SH "ERRORS" .Bl -tag -width Er
.TP 15 .It Bq Er EFAULT
[EFAULT] Either the
Either the \fIucp\fP or \fIoucp\fP is a NULL pointer. .Va ucp
.TP 15 or
[EINVAL] .Va oucp
is a NULL pointer.
.It Bq Er EINVAL
The context is not properly initialized. The context is not properly initialized.
.TP 15 .It Bq Er ENOMEM
[ENOMEM] The
The \fIucp\fP argument does not have enough stack left to complete the operation. .Va ucp
.SH "SEE ALSO" argument does not have enough stack left to complete the operation.
.BR getcontext (3). .El
.Sh SEE ALSO
.SH "AUTHORS" .Xr getcontext 3 ,
.Xr setcontext 3
.Sh STANDARDS
The
.Fn makecontext ,
and
.Fn swapcontext
functions conform to
.St -xsh5
and
.St -p1003.1-2001 .
.Sh AUTHORS
Thomas Veerman Thomas Veerman