Is there a C function like sprintf in the Linux kernel?

Question

Is there function like sprintf() in Linux Kernel (like printf()->printk())?

Answer 1

yes there is check out here for example

you can use grep to see if it is in the kernel's source code

Answer 2

yes. https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/lib/vsprintf.c#n1828

int snprintf(char *buf, size_t size, const char *fmt, ...)
{
    va_list args;
    int i;

    va_start(args, fmt);
    i = vsnprintf(buf, size, fmt, args);
    va_end(args);

    return i;
}
EXPORT_SYMBOL(snprintf);

sprintf() by itself is prone to buffer overflows. ^{CERT buffer overflows, Apple, etc}

Answer 3

Running crash on a live 2.6 kernel confirms sprintf() is defined, and where it is defined.

crash> sym sprintf

ffffffff81267ba0 (T) sprintf ../debug/kernel-2.6.39/linux-2.6.39-400.210.2.el6uek/lib/vsprintf.c: 1442

Answer 4

Yes, just include linux/kernel.h

Answer 5

sprintf() is unsafe because of buffer overflow. If you need to pass data from user space to kernel space, use instead copy_from_user(); it acts like copy_to_user() but in reverse direction.