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[Michael Schmitt]

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SheepShaver includes the C errno string in many error messages. One case is when it calls the memory allocation routines in the Basilisk II vm_alloc.cpp program.

This works when the memory allocation routine uses functions that set errno (such as mmap or malloc). For example, running SheepShaver on a Linux hosts produces meaningful error messages.

The problem is that when run on an OS X host, the memory allocation uses Mach routines such as vm_allocate, which do not set errno.

So when SheepShaver reported the error, it used a stale value of errno, which happened to be 17. The result was an extremely misleading error message: "Cannot map RAM: File already exists".

The fix is to change vm_alloc so that it translates Mac return codes into POSIX errno values.

It also initializes errno to 0 at the start of the memory allocation routine, so that no matter what path it takes, it won't return a stale value.
This commit is contained in:
asvitkine 2009-08-11 07:43:46 +00:00
parent fbef7bcf22
commit c6d88f213c
1 changed files with 31 additions and 2 deletions
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33
BasiliskII/src/Unix/vm_alloc.cpp
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@ -32,6 +32,7 @@
#include <windows.h>
#endif
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -151,6 +152,24 @@ static int translate_prot_flags(int prot_flags)
}
#endif
/* Translate Mach return codes to POSIX errno values. */
#ifdef HAVE_MACH_VM
static int vm_error(kern_return_t ret_code)
{
switch (ret_code) {
case KERN_SUCCESS:
return 0;
case KERN_INVALID_ADDRESS:
case KERN_NO_SPACE:
return ENOMEM;
case KERN_PROTECTION_FAILURE:
return EACCES;
default:
return EINVAL;
}
}
#endif
/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
int vm_init(void)
@ -186,6 +205,8 @@ void vm_exit(void)
void * vm_acquire(size_t size, int options)
{
void * addr;
errno = 0;
// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
if (options & VM_MAP_FIXED)
@ -198,8 +219,11 @@ void * vm_acquire(size_t size, int options)
#ifdef HAVE_MACH_VM
// vm_allocate() returns a zero-filled memory region
if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE);
if (ret_code != KERN_SUCCESS) {
errno = vm_error(ret_code);
return VM_MAP_FAILED;
}
#else
#ifdef HAVE_MMAP_VM
int fd = zero_fd;
@ -244,6 +268,8 @@ void * vm_acquire(size_t size, int options)
int vm_acquire_fixed(void * addr, size_t size, int options)
{
errno = 0;
// Fixed mappings are required to be private
if (options & VM_MAP_SHARED)
return -1;
@ -255,8 +281,11 @@ int vm_acquire_fixed(void * addr, size_t size, int options)
#ifdef HAVE_MACH_VM
// vm_allocate() returns a zero-filled memory region
if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0);
if (ret_code != KERN_SUCCESS) {
errno = vm_error(ret_code);
return -1;
}
#else
#ifdef HAVE_MMAP_VM
int fd = zero_fd;