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author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
commit | be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da (patch) | |
tree | a18a706dffa5baf86a3b12bbfb4f81caa097f349 /lib/libc/sys/getrlimit.2 | |
parent | 2a27bd86e6002c871e3b5561a5334653bb222a77 (diff) | |
download | FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.zip FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.tar.gz |
BSD 4.4 Lite Lib Sources
Diffstat (limited to 'lib/libc/sys/getrlimit.2')
-rw-r--r-- | lib/libc/sys/getrlimit.2 | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/lib/libc/sys/getrlimit.2 b/lib/libc/sys/getrlimit.2 new file mode 100644 index 0000000..9aa3c8e --- /dev/null +++ b/lib/libc/sys/getrlimit.2 @@ -0,0 +1,191 @@ +.\" Copyright (c) 1980, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)getrlimit.2 8.1 (Berkeley) 6/4/93 +.\" +.Dd June 4, 1993 +.Dt GETRLIMIT 2 +.Os BSD 4 +.Sh NAME +.Nm getrlimit , +.Nm setrlimit +.Nd control maximum system resource consumption +.Sh SYNOPSIS +.Fd #include <sys/types.h> +.Fd #include <sys/time.h> +.Fd #include <sys/resource.h> +.Ft int +.Fn getrlimit "int resource" "struct rlimit *rlp" +.Ft int +.Fn setrlimit "int resource" "struct rlimit *rlp" +.Sh DESCRIPTION +Limits on the consumption of system resources by the current process +and each process it creates may be obtained with the +.Fn getrlimit +call, and set with the +.Fn setrlimit +call. +.Pp +The +.Fa resource +parameter is one of the following: +.Bl -tag -width RLIMIT_FSIZEAA +.It Li RLIMIT_CORE +The largest size (in bytes) +.Xr core +file that may be created. +.It Li RLIMIT_CPU +The maximum amount of cpu time (in seconds) to be used by +each process. +.It Li RLIMIT_DATA +The maximum size (in bytes) of the data segment for a process; +this defines how far a program may extend its break with the +.Xr sbrk 2 +system call. +.It Li RLIMIT_FSIZE +The largest size (in bytes) file that may be created. +.It Li RLIMIT_MEMLOCK +The maximum size (in bytes) which a process may lock into memory +using the +.Xr mlock 2 +function. +.It Li RLIMIT_NOFILE +The maximum number of open files for this process. +.It Li RLIMIT_NPROC +The maximum number of simultaneous processes for this user id. +.It Li RLIMIT_RSS +The maximum size (in bytes) to which a process's resident set size may +grow. +This imposes a limit on the amount of physical memory to be given to +a process; if memory is tight, the system will prefer to take memory +from processes that are exceeding their declared resident set size. +.It Li RLIMIT_STACK +The maximum size (in bytes) of the stack segment for a process; +this defines how far a program's stack segment may be extended. +Stack extension is performed automatically by the system. +.El +.Pp +A resource limit is specified as a soft limit and a hard limit. When a +soft limit is exceeded a process may receive a signal (for example, if +the cpu time or file size is exceeded), but it will be allowed to +continue execution until it reaches the hard limit (or modifies +its resource limit). The +.Em rlimit +structure is used to specify the hard and soft limits on a resource, +.Bd -literal -offset indent +struct rlimit { + quad_t rlim_cur; /* current (soft) limit */ + quad_t rlim_max; /* hard limit */ +}; +.Ed +.Pp +Only the super-user may raise the maximum limits. Other users +may only alter +.Fa rlim_cur +within the range from 0 to +.Fa rlim_max +or (irreversibly) lower +.Fa rlim_max . +.Pp +An +.Dq infinite +value for a limit is defined as +.Dv RLIM_INFINITY . +.Pp +Because this information is stored in the per-process information, +this system call must be executed directly by the shell if it +is to affect all future processes created by the shell; +.Ic limit +is thus a built-in command to +.Xr csh 1 . +.Pp +The system refuses to extend the data or stack space when the limits +would be exceeded in the normal way: a +.Xr break +call fails if the data space limit is reached. +When the stack limit is reached, the process receives +a segmentation fault +.Pq Dv SIGSEGV ; +if this signal is not +caught by a handler using the signal stack, this signal +will kill the process. +.Pp +A file I/O operation that would create a file larger that the process' +soft limit will cause the write to fail and a signal +.Dv SIGXFSZ +to be +generated; this normally terminates the process, but may be caught. When +the soft cpu time limit is exceeded, a signal +.Dv SIGXCPU +is sent to the +offending process. +.Sh RETURN VALUES +A 0 return value indicates that the call succeeded, changing +or returning the resource limit. A return value of -1 indicates +that an error occurred, and an error code is stored in the global +location +.Va errno . +.Sh ERRORS +.Fn Getrlimit +and +.Fn setrlimit +will fail if: +.Bl -tag -width Er +.It Bq Er EFAULT +The address specified for +.Fa rlp +is invalid. +.It Bq Er EPERM +The limit specified to +.Fn setrlimit +would have +raised the maximum limit value, and the caller is not the super-user. +.El +.Sh SEE ALSO +.Xr csh 1 , +.Xr quota 2 , +.Xr sigaltstack 2 , +.Xr sigvec 2 , +.Xr sysctl 3 +.Sh BUGS +There should be +.Ic limit +and +.Ic unlimit +commands in +.Xr sh 1 +as well as in +.Xr csh . +.Sh HISTORY +The +.Nm +function call appeared in +.Bx 4.2 . |