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/* User memory access */
#include <stdio.h>
#include <string.h>
#include "qemu.h"
/* 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.
*/
abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
{
abi_long ret = 0;
void *ghptr;
if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) {
memcpy(hptr, ghptr, len);
unlock_user(ghptr, gaddr, 0);
} else
ret = -TARGET_EFAULT;
return ret;
}
abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
{
abi_long ret = 0;
void *ghptr;
if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) {
memcpy(ghptr, hptr, len);
unlock_user(ghptr, gaddr, len);
} else
ret = -TARGET_EFAULT;
return ret;
}
/* XXX: use host strnlen if available ? */
static int qemu_strnlen(const char *s, int max_len)
{
int i;
for(i = 0; i < max_len; i++) {
if (s[i] == '\0')
break;
}
return i;
}
/* Return the length of a string in target memory or -TARGET_EFAULT if
access error */
abi_long target_strlen(abi_ulong guest_addr1)
{
uint8_t *ptr;
abi_ulong guest_addr;
int 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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