diff options
| author | cinap_lenrek <cinap_lenrek@gmx.de> | 2013-09-24 01:52:20 +0200 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@gmx.de> | 2013-09-24 01:52:20 +0200 |
| commit | 62b3eea2715a9e67cdb0873faa0d802344bf7683 (patch) | |
| tree | 4b6449a693ab7f6a14bf819c81917d2eb10d40e3 /sys/src/9/port/sysproc.c | |
| parent | 365fd745d62e9fdc43b22a0a1916c595749eb575 (diff) | |
syssem*: eleminate redundant validaddr() checks
validaddr looks up the segments for an address range
and checks the flags and if the address range lies
within bounds on the segments.
as we'r going to lookup the segment in the syssem*
syscalls anyway, we can do the checks ourselfs avoiding
the double segment array lookups.
the implication of this tho is that now a semaphore cannot
span multiple segments. but this would be highly unusual
given that segments are page aligned.
Diffstat (limited to 'sys/src/9/port/sysproc.c')
| -rw-r--r-- | sys/src/9/port/sysproc.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/sys/src/9/port/sysproc.c b/sys/src/9/port/sysproc.c index 9f670a5a0..fbad6942f 100644 --- a/sys/src/9/port/sysproc.c +++ b/sys/src/9/port/sysproc.c @@ -1109,13 +1109,15 @@ syssemacquire(ulong *arg) long *addr; Segment *s; - validaddr(arg[0], sizeof(long), 1); evenaddr(arg[0]); addr = (long*)arg[0]; block = arg[1]; - - if((s = seg(up, (ulong)addr, 0)) == nil) + + s = seg(up, (ulong)addr, 0); + if(s == nil || (s->type&SG_RONLY) != 0 || (ulong)addr+sizeof(long) > s->top){ + validaddr((ulong)addr, sizeof(long), 1); error(Ebadarg); + } if(*addr < 0) error(Ebadarg); return semacquire(s, addr, block); @@ -1128,13 +1130,15 @@ systsemacquire(ulong *arg) ulong ms; Segment *s; - validaddr(arg[0], sizeof(long), 1); evenaddr(arg[0]); addr = (long*)arg[0]; ms = arg[1]; - if((s = seg(up, (ulong)addr, 0)) == nil) + s = seg(up, (ulong)addr, 0); + if(s == nil || (s->type&SG_RONLY) != 0 || (ulong)addr+sizeof(long) > s->top){ + validaddr((ulong)addr, sizeof(long), 1); error(Ebadarg); + } if(*addr < 0) error(Ebadarg); return tsemacquire(s, addr, ms); @@ -1146,13 +1150,15 @@ syssemrelease(ulong *arg) long *addr, delta; Segment *s; - validaddr(arg[0], sizeof(long), 1); evenaddr(arg[0]); addr = (long*)arg[0]; delta = arg[1]; - if((s = seg(up, (ulong)addr, 0)) == nil) + s = seg(up, (ulong)addr, 0); + if(s == nil || (s->type&SG_RONLY) != 0 || (ulong)addr+sizeof(long) > s->top){ + validaddr((ulong)addr, sizeof(long), 1); error(Ebadarg); + } /* delta == 0 is a no-op, not a release */ if(delta < 0 || *addr < 0) error(Ebadarg); |