1 /* User memory access */ 2 #include <stdio.h> 3 #include <string.h> 4 5 #include "qemu.h" 6 7 /* copy_from_user() and copy_to_user() are usually used to copy data 8 * buffers between the target and host. These internally perform 9 * locking/unlocking of the memory. 10 */ 11 abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len) 12 { 13 abi_long ret = 0; 14 void *ghptr; 15 16 if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) { 17 memcpy(hptr, ghptr, len); 18 unlock_user(ghptr, gaddr, 0); 19 } else 20 ret = -TARGET_EFAULT; 21 22 return ret; 23 } 24 25 26 abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len) 27 { 28 abi_long ret = 0; 29 void *ghptr; 30 31 if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) { 32 memcpy(ghptr, hptr, len); 33 unlock_user(ghptr, gaddr, len); 34 } else 35 ret = -TARGET_EFAULT; 36 37 return ret; 38 } 39 40 /* XXX: use host strnlen if available ? */ 41 static int qemu_strnlen(const char *s, int max_len) 42 { 43 int i; 44 for(i = 0; i < max_len; i++) { 45 if (s[i] == '\0') 46 break; 47 } 48 return i; 49 } 50 51 /* Return the length of a string in target memory or -TARGET_EFAULT if 52 access error */ 53 abi_long target_strlen(abi_ulong guest_addr1) 54 { 55 uint8_t *ptr; 56 abi_ulong guest_addr; 57 int max_len, len; 58 59 guest_addr = guest_addr1; 60 for(;;) { 61 max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK); 62 ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1); 63 if (!ptr) 64 return -TARGET_EFAULT; 65 len = qemu_strnlen((const char *)ptr, max_len); 66 unlock_user(ptr, guest_addr, 0); 67 guest_addr += len; 68 /* we don't allow wrapping or integer overflow */ 69 if (guest_addr == 0 || 70 (guest_addr - guest_addr1) > 0x7fffffff) 71 return -TARGET_EFAULT; 72 if (len != max_len) 73 break; 74 } 75 return guest_addr - guest_addr1; 76 } 77