intro(2)
NAME
Intro, intro - introduction to system calls and error
numbers
SYNOPSIS
#include <errno.h>
DESCRIPTION
This section describes all of the system calls. Most of
these calls return one or more error conditions. An error
condition is indicated by an otherwise impossible return
value. This is almost always -1 or the null pointer; the
individual descriptions specify the details. An error
number is also made available in the external variable
errno, which is not cleared on successful calls, so it
should be tested only after an error has been indicated.
In the case of multithreaded applications, the -mt option
must be specified on the command line at compilation time
(see threads(3THR)). When the -mt option is specified,
errno becomes a macro that enables each thread to have its
own errno. This errno macro can be used on either side of
the assignment as though it were a variable.
Applications should use bound threads rather than the
_lwp_*() functions (see thr_create(3THR)). Using LWPs
(lightweight processes) directly is not advised because
libraries are only safe to use with threads, not LWPs.
Each system call description attempts to list all possible
error numbers. The following is a complete list of the error
numbers and their names as defined in <errno.h>.
1 EPERM
Not superuser
Typically this error indicates an attempt to modify a
file in some way forbidden except to its owner or the
super-user. It is also returned for attempts by ordi-
nary users to do things allowed only to the super-
user.
2 ENOENT
No such file or directory
A file name is specified and the file should exist but
doesn't, or one of the directories in a path name does
not exist.
3 ESRCH
No such process, LWP, or thread
No process can be found in the system that corresponds
to the specified PID, LWPID_t, or thread_t.
4 EINTR
Interrupted system call
An asynchronous signal (such as interrupt or quit),
which the user has elected to catch, occurred during a
system service function. If execution is resumed after
processing the signal, it will appear as if the inter-
rupted function call returned this error condition.
In a multithreaded application, EINTR may be returned
whenever another thread or LWP calls fork(2).
5 EIO I/O error
Some physical I/O error has occurred. This error may
in some cases occur on a call following the one to
which it actually applies.
6 ENXIO
No such device or address
I/O on a special file refers to a subdevice which does
not exist, or exists beyond the limit of the device.
It may also occur when, for example, a tape drive is
not on-line or no disk pack is loaded on a drive.
7 E2BIG
Arg list too long
An argument list longer than ARG_MAX bytes is
presented to a member of the exec family of functions
(see exec(2)). The argument list limit is the sum of
the size of the argument list plus the size of the
environment's exported shell variables.
8 ENOEXEC
Exec format error
A request is made to execute a file which, although it
has the appropriate permissions, does not start with a
valid format (see a.out(4)).
9 EBADF
Bad file number
Either a file descriptor refers to no open file, or a
read(2) (respectively, write(2)) request is made to
a file that is open only for writing (respectively,
reading).
10 ECHILD
No child processes
A wait(2) function was executed by a process that had
no existing or unwaited-for child processes.
11 EAGAIN
No more processes, or no more LWPs
For example, the fork(2) function failed because the
system's process table is full or the user is not
allowed to create any more processes, or a call failed
because of insufficient memory or swap space.
12 ENOMEM
Not enough space
During execution of brk() or sbrk() (see brk(2)), or
one of the exec family of functions, a program asks
for more space than the system is able to supply. This
is not a temporary condition; the maximum size is a
system parameter. On some architectures, the error may
also occur if the arrangement of text, data, and stack
segments requires too many segmentation registers, or
if there is not enough swap space during the fork(2)
function. If this error occurs on a resource associ-
ated with Remote File Sharing (RFS), it indicates a
memory depletion which may be temporary, dependent on
system activity at the time the call was invoked.
13 EACCES
Permission denied
An attempt was made to access a file in a way forbid-
den by the protection system.
14 EFAULT
Bad address
The system encountered a hardware fault in attempting
to use an argument of a routine. For example, errno
potentially may be set to EFAULT any time a routine
that takes a pointer argument is passed an invalid
address, if the system can detect the condition.
Because systems will differ in their ability to reli-
ably detect a bad address, on some implementations
passing a bad address to a routine will result in
undefined behavior.
15 ENOTBLK
Block device required
A non-block device or file was mentioned where a block
device was required (for example, in a call to the
mount(2) function).
16 EBUSY
Device busy
An attempt was made to mount a device that was already
mounted or an attempt was made to unmount a device on
which there is an active file (open file, current
directory, mounted-on file, active text segment). It
will also occur if an attempt is made to enable
accounting when it is already enabled. The device or
resource is currently unavailable. EBUSY is also
used by mutexes, semaphores, condition variables, and
r/w locks, to indicate that a lock is held, and by
the processor control function P_ONLINE.
17 EEXIST
File exists
An existing file was mentioned in an inappropriate
context (for example, call to the link(2) function).
18 EXDEV
Cross-device link
A hard link to a file on another device was attempted.
19 ENODEV
No such device
An attempt was made to apply an inappropriate opera-
tion to a device (for example, read a write-only dev-
ice).
20 ENOTDIR
Not a directory
A non-directory was specified where a directory is
required (for example, in a path prefix or as an argu-
ment to the chdir(2) function).
21 EISDIR
Is a directory
An attempt was made to write on a directory.
22 EINVAL
Invalid argument
An invalid argument was specified (for example,
unmounting a non-mounted device), mentioning an unde-
fined signal in a call to the signal(3C) or kill(2)
function, or an unsupported operation related to
extended attributes was attempted.
23 ENFILE
File table overflow
The system file table is full (that is, SYS_OPEN
files are open, and temporarily no more files can be
opened).
24 EMFILE
Too many open files
No process may have more than OPEN_MAX file descrip-
tors open at a time.
25 ENOTTY
Inappropriate ioctl for device
A call was made to the ioctl(2) function specifying a
file that is not a special character device.
26 ETXTBSY
Text file busy (obselete)
An attempt was made to execute a pure-procedure pro-
gram that is currently open for writing. Also an
attempt to open for writing or to remove a pure-
procedure program that is being executed. (This mes-
sage is obsolete.)
27 EFBIG
File too large
The size of the file exceeded the limit specified by
resource RLIMIT_FSIZE ; the file size exceeds the
maximum supported by the file system; or the file size
exceeds the offset maximum of the file descriptor.
See the File Descriptor subsection of the DEFINITIONS
section below.
28 ENOSPC
No space left on device
While writing an ordinary file or creating a directory
entry, there is no free space left on the device. In
the fcntl(2) function, the setting or removing of
record locks on a file cannot be accomplished because
there are no more record entries left on the system.
29 ESPIPE
Illegal seek
A call to the lseek(2) function was issued to a pipe.
30 EROFS
Read-only file system
An attempt to modify a file or directory was made on a
device mounted read-only.
31 EMLINK
Too many links
An attempt to make more than the maximum number of
links, LINK_MAX, to a file.
32 EPIPE
Broken pipe
A write on a pipe for which there is no process to
read the data. This condition normally generates a
signal; the error is returned if the signal is
ignored.
33 EDOM
Math argument out of domain of function
The argument of a function in the math package (3M) is
out of the domain of the function.
34 ERANGE
Math result not representable
The value of a function in the math package (3M) is
not representable within machine precision.
35 ENOMSG
No message of desired type
An attempt was made to receive a message of a type
that does not exist on the specified message queue
(see msgrcv(2)).
36 EIDRM
Identifier removed
This error is returned to processes that resume execu-
tion due to the removal of an identifier from the file
system's name space (see msgctl(2), semctl(2), and
shmctl(2)).
37 ECHRNG
Channel number out of range
38 EL2NSYNC
Level 2 not synchronized
39 EL3HLT
Level 3 halted
40 EL3RST
Level 3 reset
41 ELNRNG
Link number out of range
42 EUNATCH
Protocol driver not attached
43 ENOCSI
No CSI structure available
44 EL2HLT
Level 2 halted
45 EDEADLK
Deadlock condition
A deadlock situation was detected and avoided. This
error pertains to file and record locking, and also
applies to mutexes, semaphores, condition variables,
and r/w locks.
46 ENOLCK
No record locks available
There are no more locks available. The system lock
table is full (see fcntl(2)).
47 ECANCELED
Operation canceled
The associated asynchronous operation was canceled
before completion.
48 ENOTSUP
Not supported
This version of the system does not support this
feature. Future versions of the system may provide
support.
49 EDQUOT
Disc quota exceeded
A write(2) to an ordinary file, the creation of a
directory or symbolic link, or the creation of a
directory entry failed because the user's quota of
disk blocks was exhausted, or the allocation of an
inode for a newly created file failed because the
user's quota of inodes was exhausted.
58-59 Reserved
60 ENOSTR
Device not a stream
A putmsg(2) or getmsg(2) call was attempted on a file
descriptor that is not a STREAMS device.
61 ENODATA
No data available
62 ETIME
Timer expired
The timer set for a STREAMS ioctl(2) call has expired.
The cause of this error is device-specific and could
indicate either a hardware or software failure, or
perhaps a timeout value that is too short for the
specific operation. The status of the ioctl() opera-
tion is indeterminate. This is also returned in the
case of _lwp_cond_timedwait(2) or
cond_timedwait(3THR).
63 ENOSR
Out of stream resources
During a STREAMS open(2) call, either no STREAMS
queues or no STREAMS head data structures were avail-
able. This is a temporary condition; one may recover
from it if other processes release resources.
64 ENONET
Machine is not on the network
This error is Remote File Sharing (RFS) specific. It
occurs when users try to advertise, unadvertise,
mount, or unmount remote resources while the machine
has not done the proper startup to connect to the net-
work.
65 ENOPKG
Package not installed
This error occurs when users attempt to use a call
from a package which has not been installed.
66 EREMOTE
Object is remote
This error is RFS-specific. It occurs when users try
to advertise a resource which is not on the local
machine, or try to mount/unmount a device (or path-
name) that is on a remote machine.
67 ENOLINK
Link has been severed
This error is RFS-specific. It occurs when the link
(virtual circuit) connecting to a remote machine is
gone.
68 EADV
Advertise error
This error is RFS-specific. It occurs when users try
to advertise a resource which has been advertised
already, or try to stop RFS while there are resources
still advertised, or try to force unmount a resource
when it is still advertised.
69 ESRMNT
Srmount error
This error is RFS-specific. It occurs when an attempt
is made to stop RFS while resources are still mounted
by remote machines, or when a resource is readvertised
with a client list that does not include a remote
machine that currently has the resource mounted.
70 ECOMM
Communication error on send
This error is RFS-specific. It occurs when the current
process is waiting for a message from a remote
machine, and the virtual circuit fails.
71 EPROTO
Protocol error
Some protocol error occurred. This error is device-
specific, but is generally not related to a hardware
failure.
76 EDOTDOT
Error 76
This error is RFS-specific. A way for the server to
tell the client that a process has transferred back
from mount point.
77 EBADMSG
Not a data message
During a read(2), getmsg(2), or ioctl(2) I_RECVFD call
to a STREAMS device, something has come to the head of
the queue that can not be processed. That something
depends on the call:
read():
control information or passed file descriptor.
getmsg():
passed file descriptor.
ioctl():
control or data information.
78 ENAMETOOLONG
File name too long
The length of the path argument exceeds PATH_MAX, or
the length of a path component exceeds NAME_MAX while
_POSIX_NO_TRUNC is in effect; see limits(4).
79 EOVERFLOW
Value too large for defined data type.
80 ENOTUNIQ
Name not unique on network
Given log name not unique.
81 EBADFD
File descriptor in bad state
Either a file descriptor refers to no open file or a
read request was made to a file that is open only for
writing.
82 EREMCHG
Remote address changed
83 ELIBACC
Cannot access a needed share library
Trying to exec an a.out that requires a static shared
library and the static shared library does not exist
or the user does not have permission to use it.
84 ELIBBAD
Accessing a corrupted shared library
Trying to exec an a.out that requires a static shared
library (to be linked in) and exec could not load the
static shared library. The static shared library is
probably corrupted.
85 ELIBSCN
.lib section in a.out corrupted
Trying to exec an a.out that requires a static shared
library (to be linked in) and there was erroneous data
in the .lib section of the a.out. The .lib section
tells exec what static shared libraries are needed.
The a.out is probably corrupted.
86 ELIBMAX
Attempting to link in more shared libraries than sys-
tem limit
Trying to exec an a.out that requires more static
shared libraries than is allowed on the current confi-
guration of the system. See System Administration
Guide: IP Services
87 ELIBEXEC
Cannot exec a shared library directly
Attempting to exec a shared library directly.
88 EILSEQ
Error 88
Illegal byte sequence. Handle multiple characters as a
single character.
89 ENOSYS
Operation not applicable
90 ELOOP
Number of symbolic links encountered during path name
traversal exceeds MAXSYMLINKS
91 ESTART
Restartable system call
Interrupted system call should be restarted.
92 ESTRPIPE
If pipe/FIFO, don't sleep in stream head
Streams pipe error (not externally visible).
93 ENOTEMPTY
Directory not empty
94 EUSERS
Too many users
95 ENOTSOCK
Socket operation on non-socket
96 EDESTADDRREQ
Destination address required
A required address was omitted from an operation on a
transport endpoint. Destination address required.
97 EMGSIZE
Message too long
A message sent on a transport provider was larger than
the internal message buffer or some other network
limit.
98 EPROTOTYPE
Protocol wrong type for socket
A protocol was specified that does not support the
semantics of the socket type requested.
99 ENOPROTOOPT
Protocol not available
A bad option or level was specified when getting or
setting options for a protocol.
120 EPROTONOSUPPORT
Protocol not supported
The protocol has not been configured into the system
or no implementation for it exists.
121 ESOCKTNOSUPPORT
Socket type not supported
The support for the socket type has not been config-
ured into the system or no implementation for it
exists.
122 EOPNOTSUPP
Operation not supported on transport endpoint
For example, trying to accept a connection on a
datagram transport endpoint.
123 EPFNOSUPPORT
Protocol family not supported
The protocol family has not been configured into the
system or no implementation for it exists. Used for
the Internet protocols.
124 EAFNOSUPPORT
Address family not supported by protocol family
An address incompatible with the requested protocol
was used.
125 EADDRINUSE
Address already in use
User attempted to use an address already in use, and
the protocol does not allow this.
126 EADDRNOTAVAIL
Cannot assign requested address
Results from an attempt to create a transport endpoint
with an address not on the current machine.
127 ENETDOWN
Network is down
Operation encountered a dead network.
128 ENETUNREACH
Network is unreachable
Operation was attempted to an unreachable network.
129 ENETRESET
Network dropped connection because of reset
The host you were connected to crashed and rebooted.
130 ECONNABORTED
Software caused connection abort
A connection abort was caused internal to your host
machine.
131 ECONNRESET
Connection reset by peer
A connection was forcibly closed by a peer. This nor-
mally results from a loss of the connection on the
remote host due to a timeout or a reboot.
132 ENOBUFS
No buffer space available
An operation on a transport endpoint or pipe was not
performed because the system lacked sufficient buffer
space or because a queue was full.
133 EISCONN
Transport endpoint is already connected
A connect request was made on an already connected
transport endpoint; or, a sendto(3SOCKET) or
sendmsg(3SOCKET) request on a connected transport end-
point specified a destination when already connected.
134 ENOTCONN
Transport endpoint is not connected
A request to send or receive data was disallowed
because the transport endpoint is not connected and
(when sending a datagram) no address was supplied.
143 ESHUTDOWN
Cannot send after transport endpoint shutdown
A request to send data was disallowed because the
transport endpoint has already been shut down.
144 ETOOMANYREFS
Too many references: cannot splice
145 ETIMEDOUT
Connection timed out
A connect(3SOCKET) or send(3SOCKET) request failed
because the connected party did not properly respond
after a period of time; or a write(2) or fsync(3C)
request failed because a file is on an NFS file sys-
tem mounted with the soft option.
146 ECONNREFUSED
Connection refused
No connection could be made because the target machine
actively refused it. This usually results from trying
to connect to a service that is inactive on the remote
host.
147 EHOSTDOWN
Host is down
A transport provider operation failed because the des-
tination host was down.
148 EHOSTUNREACH
No route to host
A transport provider operation was attempted to an
unreachable host.
149 EALREADY
Operation already in progress
An operation was attempted on a non-blocking object
that already had an operation in progress.
150 EINPROGRESS
Operation now in progress
An operation that takes a long time to complete (such
as a connect()) was attempted on a non-blocking
object.
151 ESTALE
Stale NFS file handle
DEFINITIONS
Background Process Group
Any process group that is not the foreground process group
of a session that has established a connection with a con-
trolling terminal.
Controlling Process
A session leader that established a connection to a control-
ling terminal.
Controlling Terminal
A terminal that is associated with a session. Each session
may have, at most, one controlling terminal associated with
it and a controlling terminal may be associated with only
one session. Certain input sequences from the controlling
terminal cause signals to be sent to process groups in the
session associated with the controlling terminal; see
termio(7I).
Directory
Directories organize files into a hierarchical system where
directories are the nodes in the hierarchy. A directory is a
file that catalogs the list of files, including directories
(sub-directories), that are directly beneath it in the
hierarchy. Entries in a directory file are called links. A
link associates a file identifier with a filename. By con-
vention, a directory contains at least two links, . (dot)
and .. (dot-dot). The link called dot refers to the direc-
tory itself while dot-dot refers to its parent directory.
The root directory, which is the top-most node of the
hierarchy, has itself as its parent directory. The pathname
of the root directory is / and the parent directory of the
root directory is /.
Downstream
In a stream, the direction from stream head to driver.
Driver
In a stream, the driver provides the interface between peri-
pheral hardware and the stream. A driver can also be a
pseudo-driver, such as a multiplexor or log driver (see
log(7D)), which is not associated with a hardware device.
Effective User ID and Effective Group ID
An active process has an effective user ID and an effective
group ID that are used to determine file access permissions
(see below). The effective user ID and effective group ID
are equal to the process's real user ID and real group ID,
respectively, unless the process or one of its ancestors
evolved from a file that had the set-user-ID bit or set-
group-ID bit set (see exec(2)).
File Access Permissions
Read, write, and execute/search permissions for a file are
granted to a process if one or more of the following are
true:
o The effective user ID of the process is super-user.
o The effective user ID of the process matches the user
ID of the owner of the file and the appropriate access
bit of the "owner" portion (0700) of the file mode is
set.
o The effective user ID of the process does not match
the user ID of the owner of the file, but either the
effective group ID or one of the supplementary group
IDs of the process match the group ID of the file and
the appropriate access bit of the "group" portion
(0070) of the file mode is set.
o The effective user ID of the process does not match
the user ID of the owner of the file, and neither the
effective group ID nor any of the supplementary group
IDs of the process match the group ID of the file, but
the appropriate access bit of the "other" portion
(0007) of the file mode is set.
Otherwise, the corresponding permissions are denied.
File Descriptor
A file descriptor is a small integer used to perform I/O on
a file. The value of a file descriptor is from 0 to
(NOFILES-1). A process may have no more than NOFILES file
descriptors
open simultaneously. A file descriptor is returned by calls
such as open(2) or pipe(2). The file descriptor is used as
an argument by calls such as read(2), write(2), ioctl(2),
and close(2).
Each file descriptor has a corresponding offset maximum. For
regular files that were opened without setting the
O_LARGEFILE flag, the offset maximum is 2 Gbyte - 1 byte (2
**31 -1 bytes). For regular files that were opened with the
O_LARGEFILE flag set, the offset maximum is 2**63 -1 bytes.
File Name
Names consisting of 1 to NAME_MAX characters may be used to
name an ordinary file, special file or directory.
These characters may be selected from the set of all charac-
ter values excluding \0 (null) and the ASCII code for /
(slash).
Note that it is generally unwise to use *, ?, [, or ] as
part of file names because of the special meaning attached
to these characters by the shell (see sh(1), csh(1), and
ksh(1)). Although permitted, the use of unprintable charac-
ters in file names should be avoided.
A file name is sometimes referred to as a pathname com-
ponent. The interpretation of a pathname component is
dependent on the values of NAME_MAX and _POSIX_NO_TRUNC
associated with the path prefix of that component. If any
pathname component is longer than NAME_MAX and
_POSIX_NO_TRUNC is in effect for the path prefix of that
component (see fpathconf(2) and limits(4)), it shall be con-
sidered an error condition in that implementation. Other-
wise, the implementation shall use the first NAME_MAX bytes
of the pathname component.
Foreground Process Group
Each session that has established a connection with a con-
trolling terminal will distinguish one process group of the
session as the foreground process group of the controlling
terminal. This group has certain privileges when accessing
its controlling terminal that are denied to background pro-
cess groups.
{IOV_MAX}
Maximum number of entries in a struct iovec array.
{LIMIT}
The braces notation, {LIMIT}, is used to denote a magnitude
limitation imposed by the implementation. This indicates a
value which may be defined by a header file (without the
braces), or the actual value may be obtained at runtime by
a call to the configuration inquiry pathconf(2) with the
name argument _PC_LIMIT.
Masks
The file mode creation mask of the process used during any
create function calls to turn off permission bits in the
mode argument supplied. Bit positions that are set in
umask(cmask) are cleared in the mode of the created file.
Message
In a stream, one or more blocks of data or information, with
associated STREAMS control structures. Messages can be of
several defined types, which identify the message contents.
Messages are the only means of transferring data and commun-
icating within a stream.
Message Queue
In a stream, a linked list of messages awaiting processing
by a module or driver.
Message Queue Identifier
A message queue identifier (msqid) is a unique positive
integer created by a msgget(2) call. Each msqid has a mes-
sage queue and a data structure associated with it. The data
structure is referred to as msqid_ds and contains the fol-
lowing members:
struct ipc_perm msg_perm;
struct msg *msg_first;
struct msg *msg_last;
ulong_t msg_cbytes;
ulong_t msg_qnum;
ulong_t msg_qbytes;
pid_t msg_lspid;
pid_t msg_lrpid;
time_t msg_stime;
time_t msg_rtime;
time_t msg_ctime;
The following are descriptions of the msqid_ds structure
members:
The msg_perm member is an ipc_perm structure that specifies
the message operation permission (see below). This structure
includes the following members:
uid_t cuid; /* creator user id */
gid_t cgid; /* creator group id */
uid_t uid; /* user id */
gid_t gid; /* group id */
mode_t mode; /* r/w permission */
ulong_t seq; /* slot usage sequence # */
key_t key; /* key */
The *msg_first member is a pointer to the first message on
the queue.
The *msg_last member is a pointer to the last message on the
queue.
The msg_cbytes member is the current number of bytes on the
queue.
The msg_qnum member is the number of messages currently on
the queue.
The msg_qbytes member is the maximum number of bytes allowed
on the queue.
The msg_lspid member is the process ID of the last process
that performed a msgsnd() operation.
The msg_lrpid member is the process id of the last process
that performed a msgrcv() operation.
The msg_stime member is the time of the last msgsnd() opera-
tion.
The msg_rtime member is the time of the last msgrcv() opera-
tion.
The msg_ctime member is the time of the last msgctl() opera-
tion that changed a member of the above structure.
Message Operation Permissions
In the msgctl(2), msgget(2), msgrcv(2), and msgsnd(2) func-
tion descriptions, the permission required for an operation
is given as {token}, where token is the type of permission
needed, interpreted as follows:
00400 READ by user
00200 WRITE by user
00040 READ by group
00020 WRITE by group
00004 READ by others
00002 WRITE by others
Read and write permissions for a msqid are granted to a pro-
cess if one or more of the following are true:
o The effective user ID of the process is super-user.
o The effective user ID of the process matches
msg_perm.cuid or msg_perm.uid in the data structure
associated with msqid and the appropriate bit of the
"user" portion (0600) of msg_perm.mode is set.
o Any group ID in the process credentials from the set
(cr_gid, cr_groups) matches msg_perm.cgid or
msg_perm.gid and the appropriate bit of the "group"
portion (060) of msg_perm.mode is set.
o The appropriate bit of the "other" portion (006) of
msg_perm.mode is set."
Otherwise, the corresponding permissions are denied.
Module
A module is an entity containing processing routines for
input and output data. It always exists in the middle of a
stream, between the stream's head and a driver. A module is
the STREAMS counterpart to the commands in a shell pipeline
except that a module contains a pair of functions which
allow independent bidirectional (downstream and upstream)
data flow and processing.
Multiplexor
A multiplexor is a driver that allows streams associated
with several user processes to be connected to a single
driver, or several drivers to be connected to a single user
process. STREAMS does not provide a general multiplexing
driver, but does provide the facilities for constructing
them and for connecting multiplexed configurations of
streams.
Offset Maximum
An offset maximum is an attribute of an open file descrip-
tion representing the largest value that can be used as a
file offset.
Orphaned Process Group
A process group in which the parent of every member in the
group is either itself a member of the group, or is not a
member of the process group's session.
Path Name
A path name is a null-terminated character string starting
with an optional slash (/), followed by zero or more direc-
tory names separated by slashes, optionally followed by a
file name.
If a path name begins with a slash, the path search begins
at the root directory. Otherwise, the search begins from the
current working directory.
A slash by itself names the root directory.
Unless specifically stated otherwise, the null path name is
treated as if it named a non-existent file.
Process ID
Each process in the system is uniquely identified during its
lifetime by a positive integer called a process ID. A pro-
cess ID may not be reused by the system until the process
lifetime, process group lifetime, and session lifetime ends
for any process ID, process group ID, and session ID equal
to that process ID. Within a process, there are threads with
thread id's, called thread_t and LWPID_t. These threads are
not visible to the outside process.
Parent Process ID
A new process is created by a currently active process (see
fork(2)). The parent process ID of a process is the process
ID of its creator.
Privilege
Having appropriate privilege means having the capability to
override system restrictions.
Process Group
Each process in the system is a member of a process group
that is identified by a process group ID. Any process that
is not a process group leader may create a new process group
and become its leader. Any process that is not a process
group leader may join an existing process group that shares
the same session as the process. A newly created process
joins the process group of its parent.
Process Group Leader
A process group leader is a process whose process ID is the
same as its process group ID.
Process Group ID
Each active process is a member of a process group and is
identified by a positive integer called the process group
ID. This ID is the process ID of the group leader. This
grouping permits the signaling of related processes (see
kill(2)).
Process Lifetime
A process lifetime begins when the process is forked and
ends after it exits, when its termination has been ack-
nowledged by its parent process. See wait(2).
Process Group Lifetime
A process group lifetime begins when the process group is
created by its process group leader, and ends when the life-
time of the last process in the group ends or when the last
process in the group leaves the group.
Processor Set ID
The processors in a system may be divided into subsets,
known as processor sets. A process bound to one of these
sets will run only on processors in that set, and the pro-
cessors in the set will normally run only processes that
have been bound to the set. Each active processor set is
identified by a positive integer. See pset_create(2).
Read Queue
In a stream, the message queue in a module or driver con-
taining messages moving upstream.
Real User ID and Real Group ID
Each user allowed on the system is identified by a positive
integer (0 to MAXUID) called a real user ID.
Each user is also a member of a group. The group is identi-
fied by a positive integer called the real group ID.
An active process has a real user ID and real group ID that
are set to the real user ID and real group ID, respectively,
of the user responsible for the creation of the process.
Root Directory and Current Working Directory
Each process has associated with it a concept of a root
directory and a current working directory for the purpose of
resolving path name searches. The root directory of a pro-
cess need not be the root directory of the root file system.
Saved Resource Limits
Saved resource limits is an attribute of a process that pro-
vides some flexibility in the handling of unrepresentable
resource limits, as described in the exec family of func-
tions and setrlimit(2).
Saved User ID and Saved Group ID
The saved user ID and saved group ID are the values of the
effective user ID and effective group ID just after an exec
of a file whose set user or set group file mode bit has been
set (see exec(2)).
Semaphore Identifier
A semaphore identifier (semid) is a unique positive integer
created by a semget(2) call. Each semid has a set of sema-
phores and a data structure associated with it. The data
structure is referred to as semid_ds and contains the fol-
lowing members:
struct ipc_perm sem_perm; /* operation permission struct */
struct sem *sem_base; /* ptr to first semaphore in set */
ushort_t sem_nsems; /* number of sems in set */
time_t sem_otime; /* last operation time */
time_t sem_ctime; /* last change time */
/* Times measured in secs since */
/* 00:00:00 GMT, Jan. 1, 1970 */
The following are descriptions of the semid_ds structure
members:
The sem_perm member is an ipc_perm structure that specifies
the semaphore operation permission (see below). This struc-
ture includes the following members:
uid_t uid; /* user id */
gid_t gid; /* group id */
uid_t cuid; /* creator user id */
gid_t cgid; /* creator group id */
mode_t mode; /* r/a permission */
ulong_t seq; /* slot usage sequence number */
key_t key; /* key */
The sem_nsems member is equal to the number of semaphores in
the set. Each semaphore in the set is referenced by a nonne-
gative integer referred to as a sem_num. sem_num values run
sequentially from 0 to the value of sem_nsems minus 1.
The sem_otime member is the time of the last semop(2) opera-
tion.
The sem_ctime member is the time of the last semctl(2)
operation that changed a member of the above structure.
A semaphore is a data structure called sem that contains the
following members:
ushort_t semval; /* semaphore value */
pid_t sempid; /* pid of last operation */
ushort_t semncnt; /* # awaiting semval > cval */
ushort_t semzcnt; /* # awaiting semval = 0 */
The following are descriptions of the sem structure members:
The semval member is a non-negative integer that is the
actual value of the semaphore.
The sempid member is equal to the process ID of the
last process that performed a semaphore operation on
this semaphore.
The semncnt member is a count of the number of
processes that are currently suspended awaiting this
semaphore's semval to become greater than its current
value.
The semzcnt member is a count of the number of
processes that are currently suspended awaiting this
semaphore's semval to become 0.
Semaphore Operation Permissions
In the semop(2) and semctl(2) function descriptions, the
permission required for an operation is given as {token},
where token is the type of permission needed interpreted as
follows:
00400 READ by user
00200 ALTER by user
00040 READ by group
00020 ALTER by group
00004 READ by others
00002 ALTER by others
Read and alter permissions for a semid are granted to a pro-
cess if one or more of the following are true:
o The effective user ID of the process is super-user.
o The effective user ID of the process matches
sem_perm.cuid or sem_perm.uid in the data structure
associated with semid and the appropriate bit of the
"user" portion (0600) of sem_perm.mode is set.
o The effective group ID of the process matches
sem_perm.cgid or sem_perm.gid and the appropriate bit
of the "group" portion (060) of sem_perm.mode is set.
o The appropriate bit of the "other" portion (06) of
sem_perm.mode is set.
Otherwise, the corresponding permissions are denied.
Session
A session is a group of processes identified by a common ID
called a session ID, capable of establishing a connection
with a controlling terminal. Any process that is not a
process group leader may create a new session and process
group, becoming the session leader of the session and pro-
cess group leader of the process group. A newly created
process joins the session of its creator.
Session ID
Each session in the system is uniquely identified during its
lifetime by a positive integer called a session ID, the
process ID of its session leader.
Session Leader
A session leader is a process whose session ID is the same
as its process and process group ID.
Session Lifetime
A session lifetime begins when the session is created by its
session leader, and ends when the lifetime of the last pro-
cess that is a member of the session ends, or when the last
process that is a member in the session leaves the session.
Shared Memory Identifier
A shared memory identifier (shmid) is a unique positive
integer created by a shmget(2) call. Each shmid has a seg-
ment of memory (referred to as a shared memory segment) and
a data structure associated with it. (Note that these shared
memory segments must be explicitly removed by the user after
the last reference to them is removed.) The data structure
is referred to as shmid_ds and contains the following
members:
struct ipc_perm shm_perm; /* operation permission struct */
size_t shm_segsz; /* size of segment */
struct anon_map *shm_amp; /* ptr to region structure */
char pad[4]; /* for swap compatibility */
pid_t shm_lpid; /* pid of last operation */
pid_t shm_cpid; /* creator pid */
shmatt_t shm_nattch; /* number of current attaches */
ulong_t shm_cnattch; /* used only for shminfo */
time_t shm_atime; /* last attach time */
time_t shm_dtime; /* last detach time */
time_t shm_ctime; /* last change time */
/* Times measured in secs since */
/* 00:00:00 GMT, Jan. 1, 1970 */
The following are descriptions of the shmid_ds structure
members:
The shm_perm member is an ipc_perm structure that
specifies the shared memory operation permission (see
below). This structure includes the following members:
uid_t cuid; /* creator user id */
gid_t cgid; /* creator group id */
uid_t uid; /* user id */
gid_t gid; /* group id */
mode_t mode; /* r/w permission */
ulong_t seq; /* slot usage sequence # */
key_t key; /* key */
The shm_segsz member specifies the size of the shared
memory segment in bytes.
The shm_cpid member is the process ID of the process
that created the shared memory identifier.
The shm_lpid member is the process ID of the last pro-
cess that performed a shmat() or shmdt() operation (see
shmop(2)).
The shm_nattch member is the number of processes that
currently have this segment attached.
The shm_atime member is the time of the last shmat()
operation (see shmop(2)).
The shm_dtime member is the time of the last shmdt()
operation (see shmop(2)).
The shm_ctime member is the time of the last shmctl(2)
operation that changed one of the members of the above
structure.
Shared Memory Operation Permissions
In the shmctl(2), shmat(), and shmdt() (see shmop(2)) func-
tion descriptions, the permission required for an operation
is given as {token}, where token is the type of permission
needed interpreted as follows:
00400 READ by user
00200 WRITE by user
00040 READ by group
00020 WRITE by group
00004 READ by others
00002 WRITE by others
Read and write permissions for a shmid are granted to a pro-
cess if one or more of the following are true:
o The effective user ID of the process is super-user.
o The effective user ID of the process matches
shm_perm.cuid or shm_perm.uid in the data structure
associated with shmid and the appropriate bit of the
"user" portion (0600) of shm_perm.mode is set.
o The effective group ID of the process matches
shm_perm.cgid or shm_perm.gid and the appropriate bit
of the "group" portion (060) of shm_perm.mode is set.
o The appropriate bit of the "other" portion (06) of
shm_perm.mode is set.
Otherwise, the corresponding permissions are denied.
Special Processes
The process with ID 0 and the process with ID 1 are special
processes referred to as proc0 and proc1; see kill(2). proc0
is the process scheduler. proc1 is the initialization pro-
cess (init); proc1 is the ancestor of every other process in
the system and is used to control the process structure.
STREAMS
A set of kernel mechanisms that support the development of
network services and data communication drivers. It defines
interface standards for character input/output within the
kernel and between the kernel and user level processes. The
STREAMS mechanism is composed of utility routines, kernel
facilities and a set of data structures.
Stream
A stream is a full-duplex data path within the kernel
between a user process and driver routines. The primary com-
ponents are a stream head, a driver, and zero or more
modules between the stream head and driver. A stream is
analogous to a shell pipeline, except that data flow and
processing are bidirectional.
Stream Head
In a stream, the stream head is the end of the stream that
provides the interface between the stream and a user pro-
cess. The principal functions of the stream head are pro-
cessing STREAMS-related system calls and passing data and
information between a user process and the stream.
Super-user
A process is recognized as a super-user process and is
granted special privileges, such as immunity from file per-
missions, if its effective user ID is 0.
Upstream
In a stream, the direction from driver to stream head.
Write Queue
In a stream, the message queue in a module or driver con-
taining messages moving downstream.
LIST OF FUNCTIONS
Name Description
__sparc_utrap_install(2)
install a SPARC V9 user trap handler
_exit(2)
See exit(2)
_lwp_cond_broadcast(2)
See _lwp_cond_signal(2)
_lwp_cond_reltimedwait(2)
See _lwp_cond_wait(2)
_lwp_cond_signal(2)
signal a condition variable
_lwp_cond_timedwait(2)
See _lwp_cond_wait(2)
_lwp_cond_wait(2)
wait on a condition variable
_lwp_continue(2)
See _lwp_suspend(2)
_lwp_create(2)
create a new light-weight process
_lwp_detach(2)
detach an LWP
_lwp_exit(2)
terminate the calling LWP
_lwp_getprivate(2)
See _lwp_setprivate(2)
_lwp_info(2)
return the time-accounting information of a single LWP
_lwp_kill(2)
send a signal to a LWP
_lwp_makecontext(2)
initialize an LWP context
_lwp_mutex_lock(2)
mutual exclusion
_lwp_mutex_trylock(2)
See _lwp_mutex_lock(2)
_lwp_mutex_unlock(2)
See _lwp_mutex_lock(2)
_lwp_self(2)
get LWP identifier
_lwp_sema_init(2)
See _lwp_sema_wait(2)
_lwp_sema_post(2)
See _lwp_sema_wait(2)
_lwp_sema_trywait(2)
See _lwp_sema_wait(2)
_lwp_sema_wait(2)
semaphore operations
_lwp_setprivate(2)
set or get LWP specific storage
_lwp_suspend(2)
continue or suspend LWP execution
_lwp_wait(2)
wait for an LWP to terminate
access(2)
determine accessibility of a file
acct(2)
enable or disable process accounting
acl(2)
get or set a file's Access Control List (ACL)
adjtime(2)
correct the time to allow synchronization of the sys-
tem clock
alarm(2)
schedule an alarm signal
audit(2)
write a record to the audit log
auditon(2)
manipulate auditing
auditsvc(2)
write audit log to specified file descriptor
brk(2)
change the amount of space allocated for the calling
process's data segment
chdir(2)
change working directory
chmod(2)
change access permission mode of file
chown(2)
change owner and group of a file
chroot(2)
change root directory
close(2)
close a file descriptor
creat(2)
create a new file or rewrite an existing one
dup(2)
duplicate an open file descriptor
exec(2)
execute a file
execl(2)
See exec(2)
execle(2)
See exec(2)
execlp(2)
See exec(2)
execv(2)
See exec(2)
execve(2)
See exec(2)
execvp(2)
See exec(2)
exit(2)
terminate process
facl(2)
See acl(2)
fchdir(2)
See chdir(2)
fchmod(2)
See chmod(2)
fchown(2)
See chown(2)
fchownat(2)
See chown(2)
fchroot(2)
See chroot(2)
fcntl(2)
file control
fork(2)
create a new process
fork1(2)
See fork(2)
fpathconf(2)
get configurable pathname variables
fstat(2)
See stat(2)
fstatat(2)
See stat(2)
fstatvfs(2)
See statvfs(2)
futimesat(2)
See utimes(2)
getacct(2)
get, put, or write extended accounting data
getaudit(2)
get and set process audit information
getaudit_addr(2)
See getaudit(2)
getauid(2)
get and set user audit identity
getcontext(2)
get and set current user context
getdents(2)
read directory entries and put in a file system
independent format
getegid(2)
See getuid(2)
geteuid(2)
See getuid(2)
getgid(2)
See getuid(2)
getgroups(2)
get or set supplementary group access list IDs
getitimer(2)
get or set value of interval timer
getmsg(2)
get next message off a stream
getpgid(2)
See getpid(2)
getpgrp(2)
See getpid(2)
getpid(2)
get process, process group, and parent process IDs
getpmsg(2)
See getmsg(2)
getppid(2)
See getpid(2)
getprojid(2)
See settaskid(2)
getrctl(2)
See setrctl(2)
getrlimit(2)
control maximum system resource consumption
getsid(2)
get process group ID of session leader
gettaskid(2)
See settaskid(2)
getuid(2)
get real user, effective user, real group, and effec-
tive group IDs
getustack(2)
retrieve or change the address of per-LWP stack boun-
dary information
ioctl(2)
control device
issetugid(2)
determine if current executable is running setuid or
setgid
kill(2)
send a signal to a process or a group of processes
lchown(2)
See chown(2)
link(2)
link to a file
llseek(2)
move extended read/write file pointer
lseek(2)
move read/write file pointer
lstat(2)
See stat(2)
memcntl(2)
memory management control
meminfo(2)
provide information about memory
mincore(2)
determine residency of memory pages
mkdir(2)
make a directory
mknod(2)
make a directory, or a special or ordinary file
mmap(2)
map pages of memory
mount(2)
mount a file system
mprotect(2)
set protection of memory mapping
msgctl(2)
message control operations
msgget(2)
get message queue
msgids(2)
discover all message queue identifiers
msgrcv(2)
message receive operation
msgsnap(2)
message queue snapshot operation
msgsnd(2)
message send operation
munmap(2)
unmap pages of memory
nice(2)
change priority of a process
ntp_adjtime(2)
adjust local clock parameters
ntp_gettime(2)
get local clock values
open(2)
open a file
openat(2)
See open(2)
p_online(2)
return or change processor operational status
pathconf(2)
See fpathconf(2)
pause(2)
suspend process until signal
pcsample(2)
program execution time profile
pipe(2)
create an interprocess channel
poll(2)
input/output multiplexing
pread(2)
See read(2)
priocntl(2)
process scheduler control
priocntlset(2)
generalized process scheduler control
processor_bind(2)
bind LWPs to a processor
processor_info(2)
determine type and status of a processor
profil(2)
execution time profile
pset_assign(2)
See pset_create(2)
pset_bind(2)
bind LWPs to a set of processors
pset_create(2)
manage sets of processors
pset_destroy(2)
See pset_create(2)
pset_getattr(2)
See pset_setattr(2)
pset_info(2)
get information about a processor set
pset_list(2)
get list of processor sets
pset_setattr(2)
set or get processor set attributes
ptrace(2)
allows a parent process to control the execution of a
child process
putacct(2)
See getacct(2)
putmsg(2)
send a message on a stream
putpmsg(2)
See putmsg(2)
pwrite(2)
See write(2)
read(2)
read from file
readlink(2)
read the contents of a symbolic link
readv(2)
See read(2)
rename(2)
change the name of a file
renameat(2)
See rename(2)
resolvepath(2)
resolve all symbolic links of a path name
rmdir(2)
remove a directory
sbrk(2)
See brk(2)
semctl(2)
semaphore control operations
semget(2)
get set of semaphores
semids(2)
discover all semaphore identifiers
semop(2)
semaphore operations
semtimedop(2)
See semop(2)
setaudit(2)
See getaudit(2)
setaudit_addr(2)
See getaudit(2)
setauid(2)
See getauid(2)
setcontext(2)
See getcontext(2)
setegid(2)
See setuid(2)
seteuid(2)
See setuid(2)
setgid(2)
See setuid(2)
setgroups(2)
See getgroups(2)
setitimer(2)
See getitimer(2)
setpgid(2)
set process group ID
setpgrp(2)
set process group ID
setrctl(2)
set or get resource control values
setregid(2)
set real and effective group IDs
setreuid(2)
set real and effective user IDs
setrlimit(2)
See getrlimit(2)
setsid(2)
create session and set process group ID
settaskid(2)
set or get task or project IDs
setuid(2)
set user and group IDs
setustack(2)
See getustack(2)
shmat(2)
See shmop(2)
shmctl(2)
shared memory control operations
shmdt(2)
See shmop(2)
shmget(2)
get shared memory segment identifier
shmids(2)
discover all shared memory identifiers
shmop(2)
shared memory operations
sigaction(2)
detailed signal management
sigaltstack(2)
set or get signal alternate stack context
sigpending(2)
examine signals that are blocked and pending
sigprocmask(2)
change and/or examine caller's signal mask
sigsend(2)
send a signal to a process or a group of processes
sigsendset(2)
See sigsend(2)
sigsuspend(2)
install a signal mask and suspend caller until signal
sigwait(2)
wait until a signal is posted
stat(2)
get file status
statvfs(2)
get file system information
stime(2)
set system time and date
swapctl(2)
manage swap space
symlink(2)
make a symbolic link to a file
sync(2)
update super block
sysfs(2)
get file system type information
sysinfo(2)
get and set system information strings
time(2)
get time
times(2)
get process and child process times
uadmin(2)
administrative control
ulimit(2)
get and set process limits
umask(2)
set and get file creation mask
umount(2)
unmount a file system
umount2(2)
See umount(2)
uname(2)
get name of current operating system
unlink(2)
remove directory entry
unlinkat(2)
See unlink(2)
ustat(2)
get file system statistics
utime(2)
set file access and modification times
utimes(2)
set file access and modification times
vfork(2)
spawn new process in a virtual memory efficient way
vhangup(2)
virtually [ldquo ]hangup[rdquo ] the current control-
ling terminal
wait(2)
wait for child process to stop or terminate
waitid(2)
wait for child process to change state
waitpid(2)
wait for child process to change state
wracct(2)
See getacct(2)
write(2)
write on a file
writev(2)
See write(2)
yield(2)
yield execution to another lightweight process
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