How can we block write function in linux?

Question

I'm trying to block write() function in linux in my code. What can we done to block the write() function in such a way it is blocked and returns -1?

I'm trying to fail write() function, to hit an error to check the code, I've written.

Should I block or unblock I/O to fail the write() function in linux? write() function that handles file descriptor.

Answer 1

What can we done to block the write() function in such a way it is blocked and returns -1?

Options:

• Just write your own write() function that returns -1.

  ssize_t write(int fd, const void *buf, size_t s) { return -1; }
  

  A bit of trivia: glibc and musl export weak symbols for most C library functions, and your code will be linked first before C standard library. This all makes the linker prefer the function that you provide over C standard library implementation.

• Use -Wl,--wrap=write when linking and provide __wrap_write implementation.

• ptrace the program and modify return value of write