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fd = open_a_file(fd->file);
 
fd = open_a_file(fd->file);
 
dup2(fd, fd->tgt_fd);
 
dup2(fd, fd->tgt_fd);
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close(fd);
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</pre>
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Now let's remember, that a file can be opened multiple times in one task, this is happens when you e.g. start a shell. One of the <code>/dev/tty</code> or alike files will sit under 0, 1 and 2 descriptors. Not a big deal, we just expand the <code>struct fd</code>
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<pre>
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struct fd {
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struct file *file;
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int n_fds;
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int *tgt_fds;
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} *fd;
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</pre>
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and the code itself:
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<pre>
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int fd, i;
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fd = open_a_file(fd->file);
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for (i = 0; i < fd->n_fds; i++)
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dup2(fd, fd->tgt_fds[i]);
 
close(fd);
 
close(fd);
 
</pre>
 
</pre>
    
[[Category:Under the hood]]
 
[[Category:Under the hood]]