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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 $
41 .Nd control maximum system resource consumption
49 .Fn getrlimit "int resource" "struct rlimit *rlp"
51 .Fn setrlimit "int resource" "const struct rlimit *rlp"
53 Limits on the consumption of system resources by the current process
54 and each process it creates may be obtained with the
56 call, and set with the
62 parameter is one of the following:
63 .Bl -tag -width RLIMIT_FSIZEAA
65 The maximum size (in bytes) of a process' total available memory.
66 If this limit is exceeded, the
70 functions will fail and
74 Moreover, the automatic stack growth will fail as well.
76 The largest size (in bytes)
78 file that may be created.
80 The maximum amount of cpu time (in seconds) to be used by
83 The maximum size (in bytes) of the data segment for a process;
84 this defines how far a program may extend its break with the
88 The largest size (in bytes) file that may be created.
90 The maximum size (in bytes) which a process may lock into memory
95 The maximum number of open files for this process.
97 The maximum number of simultaneous processes for this user id.
99 The maximum size (in bytes) to which a process's resident set size may
101 This imposes a limit on the amount of physical memory to be given to
102 a process; if memory is tight, the system will prefer to take memory
103 from processes that are exceeding their declared resident set size.
105 The maximum size (in bytes) of the stack segment for a process;
106 this defines how far a program's stack segment may be extended.
107 Stack extension is performed automatically by the system.
109 The maximum size (in bytes) of socket buffer usage for this user.
110 This limits the amount of network memory, and hence the amount of
111 mbufs, that this user may hold at any time.
112 .It Li RLIMIT_POSIXLOCK
113 The maximum number of POSIX-type advisory-mode locks available to
117 A resource limit is specified as a soft limit and a hard limit.
118 When a soft limit is exceeded a process may receive a signal (for example, if
119 the cpu time or file size is exceeded), but it will be allowed to
120 continue execution until it reaches the hard limit (or modifies
124 structure is used to specify the hard and soft limits on a resource,
125 .Bd -literal -offset indent
127 rlim_t rlim_cur; /* current (soft) limit */
128 rlim_t rlim_max; /* maximum value for rlim_cur */
132 Only the super-user may raise the maximum limits.
133 Other users may only alter
135 within the range from 0 to
137 or (irreversibly) lower
142 value for a limit is defined as
145 Because this information is stored in the per-process information,
146 this system call must be executed directly by the shell if it
147 is to affect all future processes created by the shell;
149 is thus a built-in command to
152 The system refuses to extend the data or stack space when the limits
153 would be exceeded in the normal way: a
155 call fails if the data space limit is reached.
156 When the stack limit is reached, the process receives
159 if this signal is not
160 caught by a handler using the signal stack, this signal
161 will kill the process.
163 A file I/O operation that would create a file larger than the process'
164 soft limit will cause the write to fail and a signal
167 generated; this normally terminates the process, but may be caught.
168 When the soft cpu time limit is exceeded, a signal
181 The address specified for
185 The limit specified to
188 raised the maximum limit value, and the caller is not the super-user.
201 function call appeared in