/* 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(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;}