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/* User memory access */
#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qemu.h"
#include "user-internals.h"
void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy)
{
void *host_addr;
guest_addr = cpu_untagged_addr(thread_cpu, guest_addr);
if (!access_ok_untagged(type, guest_addr, len)) {
return NULL;
}
host_addr = g2h_untagged(guest_addr);
#ifdef CONFIG_DEBUG_REMAP
if (copy) {
host_addr = g_memdup(host_addr, len);
} else {
host_addr = g_malloc0(len);
}
#endif
return host_addr;
}
#ifdef CONFIG_DEBUG_REMAP
void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len)
{
void *host_ptr_conv;
if (!host_ptr) {
return;
}
host_ptr_conv = g2h(thread_cpu, guest_addr);
if (host_ptr == host_ptr_conv) {
return;
}
if (len > 0) {
memcpy(host_ptr_conv, host_ptr, len);
}
g_free(host_ptr);
}
#endif
void *lock_user_string(abi_ulong guest_addr)
{
ssize_t len = target_strlen(guest_addr);
if (len < 0) {
return NULL;
}
return lock_user(VERIFY_READ, guest_addr, len + 1, 1);
}
/* copy_from_user() and copy_to_user() are usually used to copy data
* buffers between the target and host. These internally perform
* locking/unlocking of the memory.
*/
int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len)
{
int ret = 0;
void *ghptr = lock_user(VERIFY_READ, gaddr, len, 1);
if (ghptr) {
memcpy(hptr, ghptr, len);
unlock_user(ghptr, gaddr, 0);
} else {
ret = -TARGET_EFAULT;
}
return ret;
}
int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len)
{
int ret = 0;
void *ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0);
if (ghptr) {
memcpy(ghptr, hptr, len);
unlock_user(ghptr, gaddr, len);
} else {
ret = -TARGET_EFAULT;
}
return ret;
}
/* Return the length of a string in target memory or -TARGET_EFAULT if
access error */
ssize_t target_strlen(abi_ulong guest_addr1)
{
uint8_t *ptr;
abi_ulong guest_addr;
size_t max_len, len;
guest_addr = guest_addr1;
for(;;) {
max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
if (!ptr)
return -TARGET_EFAULT;
len = qemu_strnlen((const char *)ptr, max_len);
unlock_user(ptr, guest_addr, 0);
guest_addr += len;
/* we don't allow wrapping or integer overflow */
if (guest_addr == 0 || (guest_addr - guest_addr1) > 0x7fffffff) {
return -TARGET_EFAULT;
}
if (len != max_len) {
break;
}
}
return guest_addr - guest_addr1;
}
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