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28 .\" @(#)getrlimit.2 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/lib/libc/sys/getrlimit.2,v 1.10.2.5 2001/12/14 18:34:00 ru Exp $
37 .Nd control maximum system resource consumption
45 .Fn getrlimit "int resource" "struct rlimit *rlp"
47 .Fn setrlimit "int resource" "const struct rlimit *rlp"
49 Limits on the consumption of system resources by the current process
50 and each process it creates may be obtained with the
52 call, and set with the
58 parameter is one of the following:
59 .Bl -tag -width ".Dv RLIMIT_POSIXLOCKS"
61 The maximum size (in bytes) of a process' total available memory.
62 If this limit is exceeded, the
66 functions will fail and
70 Moreover, the automatic stack growth will fail as well.
72 The largest size (in bytes)
74 file that may be created.
76 The maximum amount of cpu time (in seconds) to be used by
79 The maximum size (in bytes) of the data segment for a process;
80 this defines how far a program may extend its break with the
84 The largest size (in bytes) file that may be created.
86 The maximum size (in bytes) which a process may lock into memory
91 The maximum number of open files for this process.
93 The maximum number of simultaneous processes for this user id.
95 The maximum size (in bytes) to which a process's resident set size may
97 This imposes a limit on the amount of physical memory to be given to
98 a process; if memory is tight, the system will prefer to take memory
99 from processes that are exceeding their declared resident set size.
101 The maximum size (in bytes) of the stack segment for a process;
102 this defines how far a program's stack segment may be extended.
103 Stack extension is performed automatically by the system.
105 The maximum size (in bytes) of socket buffer usage for this user.
106 This limits the amount of network memory, and hence the amount of
107 mbufs, that this user may hold at any time.
108 .It Dv RLIMIT_POSIXLOCKS
109 The maximum number of POSIX-type advisory-mode locks available to
113 A resource limit is specified as a soft limit and a hard limit.
114 When a soft limit is exceeded a process may receive a signal (for example, if
115 the cpu time or file size is exceeded), but it will be allowed to
116 continue execution until it reaches the hard limit (or modifies
120 structure is used to specify the hard and soft limits on a resource,
121 .Bd -literal -offset indent
123 rlim_t rlim_cur; /* current (soft) limit */
124 rlim_t rlim_max; /* maximum value for rlim_cur */
128 Only the super-user may raise the maximum limits.
129 Other users may only alter
131 within the range from 0 to
133 or (irreversibly) lower
138 value for a limit is defined as
141 Because this information is stored in the per-process information,
142 this system call must be executed directly by the shell if it
143 is to affect all future processes created by the shell;
145 is thus a built-in command to
148 The system refuses to extend the data or stack space when the limits
149 would be exceeded in the normal way: an
151 call fails if the data space limit is reached.
152 When the stack limit is reached, the process receives
155 if this signal is not
156 caught by a handler using the signal stack, this signal
157 will kill the process.
159 A file I/O operation that would create a file larger than the process'
160 soft limit will cause the write to fail and a signal
163 generated; this normally terminates the process, but may be caught.
164 When the soft cpu time limit is exceeded, a signal
177 The address specified for
181 The limit specified to
184 raised the maximum limit value, and the caller is not the super-user.
197 function call appeared in