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For hw.{physmem,realmem,usermem} MIBs, clamp instead truncating.

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If the memory size does not fit into u_long, current code truncates
the returned value and returns complete nonsense.  Make the result
slightly more useful by clamping it at ULONG_MAX.

Reported and tested :	pho
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
kib 2018-12-29 15:55:44 +00:00
parent 987c6b35ca
commit 0bf5594c41
1 changed files with 22 additions and 11 deletions
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33
sys/kern/kern_mib.c
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@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
@ -177,35 +178,45 @@ SYSCTL_PROC(_kern, KERN_ARND, arandom,
static int
sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
{
u_long val;
u_long val, p;
val = ctob(physmem);
p = SIZE_T_MAX >> PAGE_SHIFT;
if (physmem < p)
p = physmem;
val = ctob(p);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_physmem, "LU", "");
0, 0, sysctl_hw_physmem, "LU", "");
static int
sysctl_hw_realmem(SYSCTL_HANDLER_ARGS)
{
u_long val;
val = ctob(realmem);
u_long val, p;
p = SIZE_T_MAX >> PAGE_SHIFT;
if (realmem < p)
p = realmem;
val = ctob(p);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_REALMEM, realmem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_realmem, "LU", "");
0, 0, sysctl_hw_realmem, "LU", "");
static int
sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
{
u_long val;
u_long val, p, p1;
val = ctob(physmem - vm_wire_count());
p1 = physmem - vm_wire_count();
p = SIZE_T_MAX >> PAGE_SHIFT;
if (p1 < p)
p = p1;
val = ctob(p);
return (sysctl_handle_long(oidp, &val, 0, req));
}
SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_ULONG | CTLFLAG_RD,
0, 0, sysctl_hw_usermem, "LU", "");
0, 0, sysctl_hw_usermem, "LU", "");
SYSCTL_LONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &physmem, 0, "");