/* 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; }