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 | .\" | |
| 79e6b3c8 | 5 | .\" @(#)vlimit.3 6.3 (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 | |
| 374b2a7f | 16 | .ft B |
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17 | This interface is obsoleted by getrlimit(2). |
| 18 | .br | |
| 19 | It is available from the compatibility library, libcompat. | |
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20 | .ft R |
| 21 | .PP | |
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22 | Limits the consumption by the current process and each process |
| 23 | it creates to not individually exceed | |
| 24 | .I value | |
| 25 | on the specified | |
| 26 | .I resource. | |
| 27 | If | |
| 28 | .I value | |
| 29 | is specified as \-1, then the current limit is returned and the | |
| 30 | limit is unchanged. | |
| 31 | The resources which are currently controllable are: | |
| 32 | .TP 15 | |
| 374b2a7f | 33 | LIM_NORAISE |
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34 | A pseudo-limit; if set non-zero then the limits may not be raised. |
| 35 | Only the super-user may remove the \fInoraise\fR restriction. | |
| 36 | .TP 15 | |
| 374b2a7f | 37 | LIM_CPU |
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38 | the maximum |
| 39 | number of cpu-seconds to be used by each process | |
| 40 | .TP 15 | |
| 374b2a7f | 41 | LIM_FSIZE |
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42 | the largest single file which can be created |
| 43 | .TP 15 | |
| 374b2a7f | 44 | LIM_DATA |
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45 | the maximum growth of the data+stack region via |
| 46 | .IR sbrk (2) | |
| 47 | beyond the end of the program text | |
| 48 | .TP 15 | |
| 374b2a7f | 49 | LIM_STACK |
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50 | the maximum |
| 51 | size of the automatically-extended stack region | |
| 52 | .TP 15 | |
| 374b2a7f | 53 | LIM_CORE |
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54 | the size of the largest core dump that will be created. |
| 55 | .TP 15 | |
| 374b2a7f | 56 | LIM_MAXRSS |
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57 | a soft limit for the amount of physical memory (in bytes) to be given |
| 58 | to the program. If memory is tight, the system will prefer to take memory | |
| 59 | from processes which are exceeding their declared LIM_MAXRSS. | |
| 60 | .PP | |
| 61 | Because this information is stored in the per-process information | |
| 62 | this system call must be executed directly by the shell if it | |
| 63 | is to affect all future processes created by the shell; | |
| 64 | .I limit | |
| 65 | is thus a built-in command to | |
| 66 | .IR csh (1). | |
| 67 | .PP | |
| 68 | The system refuses to extend the data or stack space when the limits | |
| 69 | would be exceeded in the normal way; a | |
| 70 | .I break | |
| 71 | call fails if the data space limit is reached, or the process is | |
| 72 | killed when the stack limit is reached (since the stack cannot be | |
| 73 | extended, there is no way to send a signal!). | |
| 74 | .PP | |
| 75 | A file i/o operation which would create a file which is too large | |
| 76 | will cause a signal SIGXFSZ to be generated, this normally terminates | |
| 77 | the process, but may be caught. | |
| 78 | When the cpu time limit is exceeded, a signal SIGXCPU is sent to the | |
| 79 | offending process; to allow it time to process the signal it is | |
| 80 | given 5 seconds grace by raising the cpu time limit. | |
| 81 | .SH SEE ALSO | |
| 82 | csh(1) | |
| 83 | .SH BUGS | |
| 3311b706 | 84 | LIM_NORAISE no longer exists. |