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32 .\" @(#)getrlimit.2 8.1 (Berkeley) 6/4/93
33 .\" $FreeBSD: src/lib/libc/sys/getrlimit.2,v 1.10.2.5 2001/12/14 18:34:00 ru Exp $
34 .\" $DragonFly: src/lib/libc/sys/getrlimit.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
42 .Nd control maximum system resource consumption
50 .Fn getrlimit "int resource" "struct rlimit *rlp"
52 .Fn setrlimit "int resource" "const struct rlimit *rlp"
54 Limits on the consumption of system resources by the current process
55 and each process it creates may be obtained with the
57 call, and set with the
63 parameter is one of the following:
64 .Bl -tag -width RLIMIT_FSIZEAA
66 The largest size (in bytes)
68 file that may be created.
70 The maximum amount of cpu time (in seconds) to be used by
73 The maximum size (in bytes) of the data segment for a process;
74 this defines how far a program may extend its break with the
78 The largest size (in bytes) file that may be created.
80 The maximum size (in bytes) which a process may lock into memory
85 The maximum number of open files for this process.
87 The maximum number of simultaneous processes for this user id.
89 The maximum size (in bytes) to which a process's resident set size may
91 This imposes a limit on the amount of physical memory to be given to
92 a process; if memory is tight, the system will prefer to take memory
93 from processes that are exceeding their declared resident set size.
95 The maximum size (in bytes) of the stack segment for a process;
96 this defines how far a program's stack segment may be extended.
97 Stack extension is performed automatically by the system.
99 The maximum size (in bytes) of socket buffer usage for this user.
100 This limits the amount of network memory, and hence the amount of
101 mbufs, that this user may hold at any time.
104 A resource limit is specified as a soft limit and a hard limit. When a
105 soft limit is exceeded a process may receive a signal (for example, if
106 the cpu time or file size is exceeded), but it will be allowed to
107 continue execution until it reaches the hard limit (or modifies
108 its resource limit). The
110 structure is used to specify the hard and soft limits on a resource,
111 .Bd -literal -offset indent
113 rlim_t rlim_cur; /* current (soft) limit */
114 rlim_t rlim_max; /* maximum value for rlim_cur */
118 Only the super-user may raise the maximum limits. Other users
121 within the range from 0 to
123 or (irreversibly) lower
128 value for a limit is defined as
131 Because this information is stored in the per-process information,
132 this system call must be executed directly by the shell if it
133 is to affect all future processes created by the shell;
135 is thus a built-in command to
138 The system refuses to extend the data or stack space when the limits
139 would be exceeded in the normal way: a
141 call fails if the data space limit is reached.
142 When the stack limit is reached, the process receives
145 if this signal is not
146 caught by a handler using the signal stack, this signal
147 will kill the process.
149 A file I/O operation that would create a file larger that the process'
150 soft limit will cause the write to fail and a signal
153 generated; this normally terminates the process, but may be caught. When
154 the soft cpu time limit is exceeded, a signal
167 The address specified for
171 The limit specified to
174 raised the maximum limit value, and the caller is not the super-user.
186 function call appeared in