How to get Linux kernel modules list from user space C code?

Question

I want to get the list of kernel modules by C code, and later on print their version.

From a script this is simple:

cat /proc/modules
lsmod

and later on, run for all drivers found:

modinfo driver_name

From C code, I can open /proc/modules, and analyze the data there, but is there a simpler way of reading this drivers list?

Answer 1

From C code, I can open /proc/modules, and analyze the data there, but is there a simpler way of reading this drivers list?

Depends on your definition of simple. The concept in Unix land of everything being a file does make everything simpler in one respect, because:

int fd = open("/proc/modules" | O_RDONLY);

while ( read(fd, &buffer, BUFFER_LIMIT) )
{
    // parse buffer
}

close(fd);

involves the same set of function calls as opening and reading any file.

The alternative mechanism would be for the kernel to allocate some memory in your process' address space pointing to that information (and you could probably do this with a custom system call) but there's really no need - as you've seen, this way works very well not just with C, but with scripts also.