/* See LICENSE file for copyright and license details. */
#include "dwm.h"

void
fatal(char *fmt, ...) {
    va_list args;

    va_start(args, fmt);
    vfprintf(stderr, fmt, args);
    va_end(args);

    if(fmt[0] && fmt[strlen(fmt)-1] == ':') {
        fputc(' ', stderr);
        perror(NULL);
    } else {
        fputc('\n', stderr);
    }

    exit(1);
}

void *
ecalloc(size_t nmemb, size_t size)
{
	void *p;

	if (!(p = calloc(nmemb, size)))
		fatal("calloc:");
	return p;
}

pid_t
getparentprocess(pid_t p)
{
	uint v = 0;

#if defined(__linux__)
	io·Stream *f;
	char buf[256];
	snprintf(buf, sizeof(buf) - 1, "/proc/%u/stat", (unsigned)p);

	if (!(f = fopen(buf, "r")))
		return (pid_t)0;

	if (fscanf(f, "%*u %*s %*c %u", (unsigned *)&v) != 1)
		v = (pid_t)0;
	fclose(f);
#elif defined(__FreeBSD__)
	struct kinfo_proc *proc = kinfo_getproc(p);
	if (!proc)
		return (pid_t)0;

	v = proc->ki_ppid;
	free(proc);
#endif
	return (pid_t)v;
}

int
isdescendent(pid_t p, pid_t c)
{
	while (p != c && c != 0)
		c = getparentprocess(c);

	return (int)c;
}