set_lowest_fd()

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Arguments:

fd

The minimum file descriptor that you want to get.

Description:

The set_lowest_fd() function sets the lowest file descriptor number that will be returned by open(), pipe(), and other functions that return file descriptors. A process with the setuid/setgid file permission bit set can use this function at the begining of main() to ensure that it never unexpectedly gets back a file descriptor equal to 0, 1, or 2, which malicious programmers sometimes cause to happen by closing stdin, stdout, or stderr before spawning the process.

Returns:

The previous lowest number (0 for the first time it's called).

Classification:

QNX OS