Python 3 – os.fchown() Method
In Python, the os
module provides access to many platform-specific functionalities such as disk and file operations, environment management, and process management. The os.fchown()
method is one such function belonging to this module that is used for changing the owner of a file using its file descriptor.
Syntax
The syntax for os.fchown()
method is:
os.fchown(fd, uid, gid)
Here, fd
is the file descriptor of the file for which the owner has to be changed. uid
and gid
are the user and group identifier numbers respectively.
Parameters
The following are the parameters of the os.fchown()
method:
Parameter | Description |
---|---|
fd | It is the file descriptor of the file for which the owner has to be modified. |
uid | It is the user identifier number of the user who would become the new owner of the file. |
gid | It is the group identifier number of the group who would become the new group owner of the file. |
Return Value
The os.fchown()
method returns None on successful execution. It can raise the following exceptions:
- OSError: if an error occurred while changing the owner of the file.
Example
Let’s look at an example of using os.fchown()
method in Python:
import os
# Open a file for reading
file = open("my_file.txt", "r")
fd = file.fileno()
# Get the user and group identifier numbers
uid = os.getuid()
gid = os.getgid()
# Change the owner of the file using its file descriptor
os.fchown(fd, uid, gid)
Here, we first open a file "my_file.txt"
using the "r"
mode, which means we are opening it in read mode. We then obtain its file descriptor using the fileno()
method of the file object.
Next, we use the os.getuid()
and os.getgid()
methods, which return the user and group identifier numbers respectively.
Finally, we use the os.fchown()
method to change the owner of the file using its file descriptor fd
, the obtained user identifier uid
and group identifier gid
.
Conclusion
The os.fchown()
method is a powerful function provided by Python’s os
module for changing the owner of a file using its file descriptor, user identifier number, and group identifier number. It can be used to provide enhanced security to files and directories by allowing only authorized users to access them.