63 lines
867 B
C++
63 lines
867 B
C++
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#include <fcntl.h>
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#include <stdio.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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bool cat_file(int fd)
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{
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struct stat st;
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if (fstat(fd, &st) == -1)
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{
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perror("stat");
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return false;
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}
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void* addr = mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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if (addr == MAP_FAILED)
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{
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perror("mmap");
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return false;
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}
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ssize_t nwrite = write(STDOUT_FILENO, addr, st.st_size);
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if (nwrite == -1)
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perror("write");
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if (munmap(addr, st.st_size) == -1)
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{
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perror("munmap");
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return false;
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}
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return true;
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}
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int main(int argc, char** argv)
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{
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int ret = 0;
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if (argc > 1)
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{
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for (int i = 1; i < argc; i++)
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{
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int fd = open(argv[i], O_RDONLY);
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if (fd == -1)
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{
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perror(argv[i]);
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ret = 1;
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continue;
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}
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if (!cat_file(fd))
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ret = 1;
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close(fd);
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}
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}
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else
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{
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if (!cat_file(STDIN_FILENO))
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ret = 1;
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}
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return ret;
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}
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