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31 lines
763 B
C++
31 lines
763 B
C++
/*
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g++ mmap0.cpp -g -O0 -o mmap && ./mmap
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*/
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#include <stdio.h>
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#include <assert.h>
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#include <sys/mman.h>
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#include <string.h>
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int main(int argc, char** argv)
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{
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int zero_fd = -1;
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int size = 64 * 1024;
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int mmap_flags = MAP_PRIVATE | MAP_ANON;
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char* vaddr = (char*)mmap(NULL, size, PROT_READ | PROT_WRITE, mmap_flags, zero_fd, 0);
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assert (vaddr != (void *)MAP_FAILED);
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printf("vaddr=%p, size=%d\n", vaddr, size);
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vaddr[0] = 0x0f;
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printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
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int REDZONE = 4096;
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mprotect(vaddr, REDZONE, PROT_NONE);
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printf("protect vaddr=%p, [0, %d]\n", vaddr, REDZONE);
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printf("try to access vaddr\n");
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vaddr[0] = 0x0f;
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printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
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return 0;
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}
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