84778508d7
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5544 c046a42c-6fe2-441c-8c8c-71466251a162
77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
/* User memory access */
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#include <stdio.h>
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#include <string.h>
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#include "qemu.h"
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/* copy_from_user() and copy_to_user() are usually used to copy data
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* buffers between the target and host. These internally perform
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* locking/unlocking of the memory.
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*/
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abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
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{
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abi_long ret = 0;
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void *ghptr;
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if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) {
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memcpy(hptr, ghptr, len);
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unlock_user(ghptr, gaddr, 0);
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} else
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ret = -TARGET_EFAULT;
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return ret;
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}
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abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
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{
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abi_long ret = 0;
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void *ghptr;
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if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) {
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memcpy(ghptr, hptr, len);
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unlock_user(ghptr, gaddr, len);
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} else
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ret = -TARGET_EFAULT;
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return ret;
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}
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/* XXX: use host strnlen if available ? */
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static int qemu_strnlen(const char *s, int max_len)
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{
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int i;
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for(i = 0; i < max_len; i++) {
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if (s[i] == '\0')
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break;
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}
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return i;
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}
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/* Return the length of a string in target memory or -TARGET_EFAULT if
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access error */
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abi_long target_strlen(abi_ulong guest_addr1)
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{
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uint8_t *ptr;
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abi_ulong guest_addr;
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int max_len, len;
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guest_addr = guest_addr1;
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for(;;) {
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max_len = TARGET_PAGE_SIZE - (guest_addr & ~TARGET_PAGE_MASK);
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ptr = lock_user(VERIFY_READ, guest_addr, max_len, 1);
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if (!ptr)
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return -TARGET_EFAULT;
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len = qemu_strnlen(ptr, max_len);
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unlock_user(ptr, guest_addr, 0);
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guest_addr += len;
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/* we don't allow wrapping or integer overflow */
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if (guest_addr == 0 ||
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(guest_addr - guest_addr1) > 0x7fffffff)
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return -TARGET_EFAULT;
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if (len != max_len)
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break;
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}
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return guest_addr - guest_addr1;
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}
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