Retrieve filename from file descriptor in C

by

You can use readlink on /proc/self/fd/NNN where NNN is the file descriptor. This will give you the name of the file as it was when it was opened — however, if the file was moved or deleted since then, it may no longer be accurate (although Linux can track renames in some cases). To verify, stat the filename given and fstat the fd you have, and make sure st_dev and st_ino are the same.

Of course, not all file descriptors refer to files, and for those you’ll see some odd text strings, such as pipe:[1538488]. Since all of the real filenames will be absolute paths, you can determine which these are easily enough. Further, as others have noted, files can have multiple hardlinks pointing to them – this will only report the one it was opened with. If you want to find all names for a given file, you’ll just have to traverse the entire filesystem.

More Related Contents:

  1. what’s the differences between r and rb in fopen
  2. Why does stat fail using a name from readdir? [duplicate]
  3. Sending file descriptor by Linux socket
  4. Increasing limit of FD_SETSIZE and select
  5. How can I convert a file pointer ( FILE* fp ) to a file descriptor (int fd)?
  6. How to check if a given file descriptor stored in a variable is still valid?
  7. fcntl, lockf, which is better to use for file locking?
  8. How to read all files in a folder using C
  9. how to enter a function to a file in c
  10. How do I make this Linux program compile? [closed]
  11. Given an executable file, display its complete path [closed]
  12. Undefined reference to pthread_create in Linux
  13. How to read the content of a file to a string in C?
  14. C: Run a System Command and Get Output? [duplicate]
  15. Canonical Mode Linux Serial Port
  16. How to use EOF to run through a text file in C?
  17. Why does stdout need explicit flushing when redirected to file?
  18. When / How does Linux load shared libraries into address space?
  19. Is it possible to determine the thread holding a mutex?
  20. How to execute a shell script from C in Linux?
  21. How to get the current time in milliseconds from C in Linux?
  22. When to use pthread_exit() and when to use pthread_join() in Linux?
  23. Execute program from within a C program
  24. Beep on Linux in C
  25. Why does forking my process cause the file to be read infinitely
  26. What does a dot before the variable name in struct mean?
  27. How to do an atomic increment and fetch in C?
  28. How do I reimplement (or wrap) a syscall function on Linux?
  29. multiple threads able to get flock at the same time
  30. How to know if a Linux system call is restartable or not?

Leave a Comment