rctl_add_rule
, rctl_get_limits
,
rctl_get_racct
,
rctl_get_rules
,
rctl_remove_rule
—
manipulate and query the resource limits database
Standard C Library (libc, -lc)
#include <sys/rctl.h>
int
rctl_add_rule
(const char
*inbufp, size_t inbuflen, char
*outbufp, size_t outbuflen);
int
rctl_get_limits
(const char
*inbufp, size_t inbuflen, char
*outbufp, size_t outbuflen);
int
rctl_get_racct
(const char
*inbufp, size_t inbuflen, char
*outbufp, size_t outbuflen);
int
rctl_get_rules
(const char
*inbufp, size_t inbuflen, char
*outbufp, size_t outbuflen);
int
rctl_remove_rule
(const char
*inbufp, size_t inbuflen, char
*outbufp, size_t outbuflen);
These system calls are used to manipulate and query the resource limits
database. For all functions, inbuflen refers to the
length of the buffer pointed to by inbufp and
outbuflen refers to the length of the buffer pointed to
by outbufp.
The rctl_add_rule
() function adds the rule
pointed to by inbufp to the resource limits database.
The outbufp and outbuflen
arguments are unused. Rule format is as described in
rctl(8),
with exceptions noted in the RULES
AND FILTERS section.
The rctl_get_limits
() function returns in
outbufp a comma-separated list of rules that apply to
the process that matches the filter specified in
inbufp. This includes rules with a subject of the
process itself as well as rules with a different subject (such as user or
loginclass) that apply to the process.
The rctl_get_racct
() function returns
resource usage information for a given subject. The subject is specified by
passing a filter in inbufp. Filter syntax is as
described in
rctl(8),
with exceptions noted in the RULES
AND FILTERS section. A comma-separated list of resources and the amount
used of each by the specified subject is returned in
outbufp. The resource and amount is formatted as
“resource=amount”.
The rctl_get_rules
() function returns in
outbufp a comma-separated list of rules from the
resource limits database that match the filter passed in
inbufp. Filter syntax is as described in
rctl(8),
with exceptions noted in the RULES
AND FILTERS section. A filter of :: may be passed
to return all rules.
The rctl_remove_rule
() function removes
all rules matching the filter passed in inbufp from
the resource limits database. Filter syntax is as described in
rctl(8),
with exceptions noted in the RULES
AND FILTERS section. outbufp and
outbuflen are unused.
This section explains how the rule and filter format described in
rctl(8)
differs from the format passed to the system calls themselves. The rctl tool
provides several conveniences that the system calls do not. When using the
system call:
- The subject must be fully specified. For example, abbreviating
‘
user
’ to
‘u
’ is not acceptable.
- User and group IDs must be numeric. For example,
‘
root
’ must be expressed as
‘0
’.
- Units are not permitted on resource amounts. For example, a quantity of
1024 bytes must be expressed as
‘
1024
’ and not
‘1k
’.
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable
errno is set to indicate the error.
The rctl system calls may fail if:
- [
ENOSYS
]
- RACCT/RCTL support is not present in the kernel or the
kern.racct.enable sysctl is 0.
- [
EINVAL
]
- The rule or filter passed in inbufp is invalid.
- [
EPERM
]
- User has insufficient privileges to carry out the requested
operation.
- [
E2BIG
]
- inbufp or outbufp are too
large.
- [
ESRCH
]
- No process matched the provided rule or filter.
- [
ENAMETOOLONG
]
- The loginclass or jail name specified is too long.
- [
ERANGE
]
- The rule amount is outside of the allowable range or
outbufp is too small.
- [
EOPNOTSUPP
]
- The requested operation is not supported for the given rule or
filter.
- [
EFAULT
]
- inbufp or outbufp refer to
invalid addresses.
The rctl family of system calls appeared in FreeBSD 9.0.
The rctl system calls were developed by Edward Tomasz
Napierala
<trasz@FreeBSD.org>
under sponsorship from the FreeBSD Foundation. This manual page was written by
Eric Badger
<badger@FreeBSD.org>.