github.com/afumu/libc@v0.0.6/musl/src/unistd/ttyname_r.c (about)

     1  #include <unistd.h>
     2  #include <errno.h>
     3  #include <sys/stat.h>
     4  #include "syscall.h"
     5  
     6  int ttyname_r(int fd, char *name, size_t size)
     7  {
     8  	struct stat st1, st2;
     9  	char procname[sizeof "/proc/self/fd/" + 3*sizeof(int) + 2];
    10  	ssize_t l;
    11  
    12  	if (!isatty(fd)) return errno;
    13  
    14  	__procfdname(procname, fd);
    15  	l = readlink(procname, name, size);
    16  
    17  	if (l < 0) return errno;
    18  	else if (l == size) return ERANGE;
    19  
    20  	name[l] = 0;
    21  
    22  	if (stat(name, &st1) || fstat(fd, &st2))
    23  		return errno;
    24  	if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
    25  		return ENODEV;
    26  
    27  	return 0;
    28  }