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28 .\" @(#)getrlimit.2 8.1 (Berkeley) 6/4/93
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 system call, and set with the
58 argument is one of the following:
59 .Bl -tag -width RLIMIT_FSIZEAA
61 The maximum amount (in bytes) of virtual memory the process is
64 The largest size (in bytes)
66 file that may be created.
68 The maximum amount of cpu time (in seconds) to be used by
71 The maximum size (in bytes) of the data segment for a process;
72 this defines how far a program may extend its break with the
76 The largest size (in bytes) file that may be created.
78 The maximum size (in bytes) which a process may lock into memory
83 The maximum number of open files for this process.
85 The maximum number of simultaneous processes for this user id.
87 The maximum size (in bytes) to which a process's resident set size may
89 This imposes a limit on the amount of physical memory to be given to
90 a process; if memory is tight, the system will prefer to take memory
91 from processes that are exceeding their declared resident set size.
93 The maximum size (in bytes) of socket buffer usage for this user.
94 This limits the amount of network memory, and hence the amount of
95 mbufs, that this user may hold at any time.
97 The maximum size (in bytes) of the stack segment for a process;
98 this defines how far a program's stack segment may be extended.
99 Stack extension is performed automatically by the system.
101 The maximum size (in bytes) of the swap space that may be reserved or
102 used by all of this user id's processes.
103 This limit is enforced only if bit 1 of the
108 for a complete description of this sysctl.
110 The maximum number of pseudo-terminals created by this user id.
113 A resource limit is specified as a soft limit and a hard limit.
115 soft limit is exceeded a process may receive a signal (for example, if
116 the cpu time or file size is exceeded), but it will be allowed to
117 continue execution until it reaches the hard limit (or modifies
121 structure is used to specify the hard and soft limits on a resource,
122 .Bd -literal -offset indent
124 rlim_t rlim_cur; /* current (soft) limit */
125 rlim_t rlim_max; /* maximum value for rlim_cur */
129 Only the super-user may raise the maximum limits.
133 within the range from 0 to
135 or (irreversibly) lower
140 value for a limit is defined as
143 Because this information is stored in the per-process information,
144 this system call must be executed directly by the shell if it
145 is to affect all future processes created by the shell;
147 is thus a built-in command to
150 The system refuses to extend the data or stack space when the limits
151 would be exceeded in the normal way: a
153 function fails if the data space limit is reached.
154 When the stack limit is reached, the process receives
157 if this signal is not
158 caught by a handler using the signal stack, this signal
159 will kill the process.
161 A file I/O operation that would create a file larger that the process'
162 soft limit will cause the write to fail and a signal
165 generated; this normally terminates the process, but may be caught.
167 the soft cpu time limit is exceeded, a signal
182 The address specified for
186 The limit specified to
189 raised the maximum limit value, and the caller is not the super-user.
202 system call appeared in