mirror of https://gitee.com/openkylin/qemu.git
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* User memory access */
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#include "qemu/osdep.h"
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#include "qemu/cutils.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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/* 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((const char *)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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