runtime: correct return value checks for mmap on darwin/freebsd

On Darwin and FreeBSD, the mmap syscall return value is returned
unmodified. This means that the return value will either be a
valid address or a positive error number.

Also check return value from mmap in SysReserve - the callers of
SysReserve expect nil to be returned if the allocation failed.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7871043

diff --git a/src/pkg/runtime/mem_darwin.c b/src/pkg/runtime/mem_darwin.c
index 04e71939440aa4a0ad1f8c185bf25007b9f71c8b..7aa607f8ee727d2809980b6ca0047ca5268493be 100644 (file)
--- a/src/pkg/runtime/mem_darwin.c
+++ b/src/pkg/runtime/mem_darwin.c
@@ -37,7 +37,12 @@ runtime·SysFree(void *v, uintptr n)
 void*
 runtime·SysReserve(void *v, uintptr n)
 {
-       return runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       void *p;
+
+       p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       if(p < (void*)4096)
+               return nil;
+       return p;
 }
 
 enum
@@ -52,7 +57,7 @@ runtime·SysMap(void *v, uintptr n)
        
        mstats.sys += n;
        p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
-       if(p == (void*)-ENOMEM)
+       if(p == (void*)ENOMEM)
                runtime·throw("runtime: out of memory");
        if(p != v)
                runtime·throw("runtime: cannot map pages in arena address space");

diff --git a/src/pkg/runtime/mem_freebsd.c b/src/pkg/runtime/mem_freebsd.c
index f217e9db1ee559c2874a3b355f0d9b6502dcde04..805e74cffba6943373787ab909a36aed6c2c339a 100644 (file)
--- a/src/pkg/runtime/mem_freebsd.c
+++ b/src/pkg/runtime/mem_freebsd.c
@@ -8,6 +8,11 @@
 #include "os_GOOS.h"
 #include "malloc.h"
 
+enum
+{
+       ENOMEM = 12,
+};
+
 void*
 runtime·SysAlloc(uintptr n)
 {
@@ -36,20 +41,20 @@ runtime·SysFree(void *v, uintptr n)
 void*
 runtime·SysReserve(void *v, uintptr n)
 {
+       void *p;
+
        // On 64-bit, people with ulimit -v set complain if we reserve too
        // much address space.  Instead, assume that the reservation is okay
        // and check the assumption in SysMap.
        if(sizeof(void*) == 8)
                return v;
        
-       return runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+       if(p < (void*)4096)
+               return nil;
+       return p;
 }
 
-enum
-{
-       ENOMEM = 12,
-};
-
 void
 runtime·SysMap(void *v, uintptr n)
 {
@@ -60,7 +65,7 @@ runtime·SysMap(void *v, uintptr n)
        // On 64-bit, we don't actually have v reserved, so tread carefully.
        if(sizeof(void*) == 8) {
                p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
-               if(p == (void*)-ENOMEM)
+               if(p == (void*)ENOMEM)
                        runtime·throw("runtime: out of memory");
                if(p != v) {
                        runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
@@ -70,7 +75,7 @@ runtime·SysMap(void *v, uintptr n)
        }
 
        p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
-       if(p == (void*)-ENOMEM)
+       if(p == (void*)ENOMEM)
                runtime·throw("runtime: out of memory");
        if(p != v)
                runtime·throw("runtime: cannot map pages in arena address space");