diff options
| -rw-r--r-- | lib/libc/gen/Makefile.inc | 4 | ||||
| -rw-r--r-- | lib/libc/gen/sysctl.3 | 55 |
2 files changed, 56 insertions, 3 deletions
diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc index 9e42d7a1e44d..cde0adc246fb 100644 --- a/lib/libc/gen/Makefile.inc +++ b/lib/libc/gen/Makefile.inc @@ -25,7 +25,7 @@ SRCS+= _rand48.c _spinlock_stub.c alarm.c arc4random.c assert.c \ setdomainname.c sethostname.c setjmperr.c setmode.c setproctitle.c \ shmat.c shmctl.c shmdt.c shmget.c siginterrupt.c siglist.c signal.c \ sigsetops.c sleep.c srand48.c stringlist.c strtofflags.c \ - sysconf.c sysctl.c sysctlbyname.c \ + sysconf.c sysctl.c sysctlbyname.c sysctlnametomib.c \ syslog.c telldir.c termios.c time.c times.c timezone.c ttyname.c \ ttyslot.c ualarm.c uname.c unvis.c usleep.c utime.c valloc.c vis.c \ wait.c wait3.c waitpid.c @@ -115,7 +115,7 @@ MLINKS+=sigsetops.3 sigaddset.3 sigsetops.3 sigdelset.3 \ sigsetops.3 sigismember.3 MLINKS+=stringlist.3 sl_add.3 stringlist.3 sl_find.3 \ stringlist.3 sl_free.3 stringlist.3 sl_init.3 -MLINKS+=sysctl.3 sysctlbyname.3 +MLINKS+=sysctl.3 sysctlbyname.3 sysctl.3 sysctlnametomib.3 MLINKS+=syslog.3 closelog.3 syslog.3 openlog.3 syslog.3 setlogmask.3 \ syslog.3 vsyslog.3 MLINKS+=tcsendbreak.3 tcdrain.3 tcsendbreak.3 tcflow.3 tcsendbreak.3 tcflush.3 diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3 index 197aefe354b8..d719b06a88a0 100644 --- a/lib/libc/gen/sysctl.3 +++ b/lib/libc/gen/sysctl.3 @@ -37,7 +37,8 @@ .Os .Sh NAME .Nm sysctl , -.Nm sysctlbyname +.Nm sysctlbyname , +.Nm sysctlnametomib .Nd get or set system information .Sh LIBRARY .Lb libc @@ -48,6 +49,8 @@ .Fn sysctl "int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" .Ft int .Fn sysctlbyname "const char *name" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" +.Ft int +.Fn sysctlnametomib "const char *name" "int *mibp" "size_t *sizep" .Sh DESCRIPTION The .Fn sysctl @@ -126,6 +129,56 @@ should be set to NULL and .Fa newlen set to 0. .Pp +The +.Fn sysctlnametomib +function accepts an ASCII representation of the name, +looks up the integer name vector, +and returns the numeric representation in the mib array pointed to by +.Fa mibp . +The number of elements in the mib array is given by the location specified by +.Fa sizep +before the call, +and that location gives the number of entries copied after a successful call. +The resulting +.Fa mib +and +.Fa size +may be used in subsequent +.Fn sysctl +calls to get the data associated with the requested ASCII name. +This interface is intended for use by applications that want to +repeatedly request the same variable (the +.Fn sysctl +function runs in about a third the time as the same request made via the +.Fn sysctlbyname +function). +The +.Fn sysctlbyname +function is also useful for fetching mib prefixes and then adding +a final component. +For example, to fetch process information +for processes with pid's less than 100: + +.Bd -literal -offset indent -compact +int i, mib[4]; +size_t len; +struct kinfo_proc kp; + +/* Fill out the first three components of the mib */ +len = 4; +sysctlnametomib("kern.proc.pid", mib, &len); + +/* Fetch and print entries for pid's < 100 */ +for (i = 0; i < 100; i++) { + mib[3] = i; + len = sizeof(kp); + if (sysctl(mib, 4, &kp, &len, NULL, 0) == -1) + perror("sysctl"); + else if (len > 0) + printkproc(&kp); +} +.Ed +.Pp The top level names are defined with a CTL_ prefix in .Aq Pa sys/sysctl.h , and are as follows. |