projects / unix-history / blame
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1 | .\" Copyright (c) 1980 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 3311b706 | 5 | .\" @(#)vlimit.3 6.2 (Berkeley) %G% |
| 59c7bf5e | 6 | .\" |
| 0223f0b6 | 7 | .TH VLIMIT 3C "" |
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8 | .UC 4 |
| 9 | .SH NAME | |
| 10 | vlimit \- control maximum system resource consumption | |
| 11 | .SH SYNOPSIS | |
| 12 | .B "#include <sys/vlimit.h>" | |
| 13 | .PP | |
| 14 | .B vlimit(resource, value) | |
| 15 | .SH DESCRIPTION | |
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16 | .ft B |
| 17 | This facility is superseded by getrlimit(2). | |
| 18 | .ft R | |
| 19 | .PP | |
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20 | Limits the consumption by the current process and each process |
| 21 | it creates to not individually exceed | |
| 22 | .I value | |
| 23 | on the specified | |
| 24 | .I resource. | |
| 25 | If | |
| 26 | .I value | |
| 27 | is specified as \-1, then the current limit is returned and the | |
| 28 | limit is unchanged. | |
| 29 | The resources which are currently controllable are: | |
| 30 | .TP 15 | |
| 374b2a7f | 31 | LIM_NORAISE |
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32 | A pseudo-limit; if set non-zero then the limits may not be raised. |
| 33 | Only the super-user may remove the \fInoraise\fR restriction. | |
| 34 | .TP 15 | |
| 374b2a7f | 35 | LIM_CPU |
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36 | the maximum |
| 37 | number of cpu-seconds to be used by each process | |
| 38 | .TP 15 | |
| 374b2a7f | 39 | LIM_FSIZE |
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40 | the largest single file which can be created |
| 41 | .TP 15 | |
| 374b2a7f | 42 | LIM_DATA |
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43 | the maximum growth of the data+stack region via |
| 44 | .IR sbrk (2) | |
| 45 | beyond the end of the program text | |
| 46 | .TP 15 | |
| 374b2a7f | 47 | LIM_STACK |
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48 | the maximum |
| 49 | size of the automatically-extended stack region | |
| 50 | .TP 15 | |
| 374b2a7f | 51 | LIM_CORE |
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52 | the size of the largest core dump that will be created. |
| 53 | .TP 15 | |
| 374b2a7f | 54 | LIM_MAXRSS |
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55 | a soft limit for the amount of physical memory (in bytes) to be given |
| 56 | to the program. If memory is tight, the system will prefer to take memory | |
| 57 | from processes which are exceeding their declared LIM_MAXRSS. | |
| 58 | .PP | |
| 59 | Because this information is stored in the per-process information | |
| 60 | this system call must be executed directly by the shell if it | |
| 61 | is to affect all future processes created by the shell; | |
| 62 | .I limit | |
| 63 | is thus a built-in command to | |
| 64 | .IR csh (1). | |
| 65 | .PP | |
| 66 | The system refuses to extend the data or stack space when the limits | |
| 67 | would be exceeded in the normal way; a | |
| 68 | .I break | |
| 69 | call fails if the data space limit is reached, or the process is | |
| 70 | killed when the stack limit is reached (since the stack cannot be | |
| 71 | extended, there is no way to send a signal!). | |
| 72 | .PP | |
| 73 | A file i/o operation which would create a file which is too large | |
| 74 | will cause a signal SIGXFSZ to be generated, this normally terminates | |
| 75 | the process, but may be caught. | |
| 76 | When the cpu time limit is exceeded, a signal SIGXCPU is sent to the | |
| 77 | offending process; to allow it time to process the signal it is | |
| 78 | given 5 seconds grace by raising the cpu time limit. | |
| 79 | .SH SEE ALSO | |
| 80 | csh(1) | |
| 81 | .SH BUGS | |
| 3311b706 | 82 | LIM_NORAISE no longer exists. |