/* doshm.c: description
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/mman.h>
#include <asm/unistd.h>

#define FUTEX_WAIT		0
#define FUTEX_WAKE		1
#define FUTEX_FD		2
#define FUTEX_REQUEUE		3
#define FUTEX_CMP_REQUEUE	4
#define FUTEX_WAKE_OP		5
#define FUTEX_LOCK_PI		6
#define FUTEX_UNLOCK_PI		7
#define FUTEX_TRYLOCK_PI	8

static inline int futex(int *uaddr, int op, int val,
			const struct timespec *utime, int *uaddr2, int val3)
{
	return syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3);
}

#define MREMAP_MAYMOVE	1

#define SYSERROR(X, Y)					\
do {							\
	if ((long)(X) == -1L) {				\
		perror(Y);				\
		exit(1);				\
	}						\
} while(0)

void format(void)
{
	fprintf(stderr, "Format: doshm <cmd> [<args> ...]\n");
	exit(2);
}

void show_maps(void)
{
	char sysbuf[256];

	sprintf(sysbuf, "cat /proc/%d/maps", getpid());
	system(sysbuf);
}

void dosysvshm(int argc, char **argv)
{
	struct shmid_ds ds;
	void *mem, *mem2;
	int shmid = -1, tmp;

	shmid = shmget(IPC_PRIVATE, 1000*1024, IPC_CREAT|0666);
	SYSERROR(shmid, "shmget");

	printf("shmid: %d\n", shmid);

	mem = shmat(shmid, NULL, 0);
	SYSERROR(mem, "shmat");

	mem2 = shmat(shmid, NULL, 0);
	SYSERROR(mem, "shmat");

	printf("memory: %p\n", mem);

	show_maps();
//	raise(SIGSTOP);

	tmp = shmctl(shmid, IPC_STAT, &ds);
	SYSERROR(tmp, "shmctl");

	printf("nattch %lu\n", ds.shm_nattch);

	tmp = shmdt(mem);
	SYSERROR(tmp, "shmdt");

	tmp = shmdt(mem2);
	SYSERROR(tmp, "shmdt");

	tmp = shmctl(shmid, IPC_RMID, NULL);
	SYSERROR(tmp, "shmctl");

	exit(0);
}

void chardev(int argc, char **argv)
{
	void *mem, *mem2;
	int fd;

	fd = open("/dev/workram", O_RDWR, 0600);
	SYSERROR(fd, "open");

	mem = mmap(NULL, 16384, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	SYSERROR(mem, "mmap");

	mem2 = mmap(NULL, 16384, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	SYSERROR(mem, "mmap2");

	printf("mem: %p\n", mem);
	printf("mem2: %p\n", mem2);

	show_maps();

	exit(0);
}

void doposixshm(int argc, char **argv)
{
	size_t size;
	void *mem, *mem2;
	int fd, tmp;

	if (argc != 3)
		format();

	size = atol(argv[2]) * 16384 * 2;

#if 1
	fd = open(argv[1], O_CREAT | O_TRUNC | O_RDWR, 0600);
	SYSERROR(fd, "open");
#else
	fd = shm_open(argv[1], O_CREAT | O_TRUNC | O_RDWR, 0600);
	SYSERROR(fd, "shm_open");
#endif

	tmp = ftruncate(fd, size);
	SYSERROR(tmp, "truncate");

	mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	SYSERROR(mem, "mmap");

	mem2 = mmap(NULL, size / 2, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 16384);
	SYSERROR(mem, "mmap2");

	show_maps();

	printf("mem: %p\n", mem);
	printf("mem2: %p\n", mem2);

	exit(0);
}

void doshrinkmmap(int argc, char **argv)
{
	size_t size;
	void *mem, *mem2;
	int fd, tmp;

	if (argc != 3)
		format();

	size = atol(argv[2]) * 16384 * 2;

	fd = open(argv[1], O_CREAT | O_TRUNC | O_RDWR, 0600);
	SYSERROR(fd, "open");

	tmp = ftruncate(fd, size + 16384);
	SYSERROR(tmp, "truncate");

	mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	SYSERROR(mem, "mmap");

	mem2 = mmap(NULL, size / 2, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 16384);
	SYSERROR(mem, "mmap2");

	printf("mem: %p\n", mem);
	printf("mem2: %p\n", mem2);

	tmp = ftruncate(fd, size);
	SYSERROR(tmp, "truncate2");

	show_maps();

	exit(0);
}

void doxmmap(int argc, char **argv, const char *file)
{
	unsigned long prot, map;
	void *mem, *mem2;
	int fd, perm;

	argc--;
	argv++;

	perm = O_RDWR;
	prot = PROT_READ | PROT_WRITE;
	map = MAP_PRIVATE;

	for (; *argv; argv++) {
		if (strcmp(*argv, "r") == 0) {
			perm = O_RDONLY;
			prot = PROT_READ;
			continue;
		}

		if (strcmp(*argv, "w") == 0) {
			perm = O_RDWR;
			prot = PROT_READ | PROT_WRITE;
			continue;
		}

		if (strcmp(*argv, "p") == 0) {
			map = MAP_PRIVATE;
			continue;
		}

		if (strcmp(*argv, "s") == 0) {
			map = MAP_SHARED;
			continue;
		}
	}

	fd = open(file, perm, 0600);
	SYSERROR(fd, "open");

	mem = mmap(NULL, 16384, prot, map, fd, 0);
	SYSERROR(mem, "mmap");

	mem2 = mmap(NULL, 16384, prot, map, fd, 0);
	SYSERROR(mem, "mmap2");

	printf("mem: %p\n", mem);
	printf("mem2: %p\n", mem2);

	show_maps();

	exit(0);
}

void doremap(int argc, char **argv)
{
	void *mem, *mem2;

	mem = mmap(NULL, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
	SYSERROR(mem, "mmap");

	mem2 = mremap(mem, 16384, 8192, MREMAP_MAYMOVE);
	SYSERROR(mem2, "mmap");

	printf("mem: %p\n", mem);
	printf("mem2: %p\n", mem2);

	show_maps();

	exit(0);
}

void dowait(int argc, char **argv)
{
	int shmid, tmp, *f, n;

	shmid = shmget(23, 4, IPC_CREAT|0666);
	SYSERROR(shmid, "shmget");

	f = shmat(shmid, NULL, 0);
	SYSERROR(f, "shmat");

	n = *f;
	printf("WAIT: %p{%x}\n", f, n);
	tmp = futex(f, FUTEX_WAIT, n, NULL, NULL, 0);
	SYSERROR(tmp, "futex");
	printf("WAITED: %d\n", tmp);

	tmp = shmdt(f);
	SYSERROR(tmp, "shmdt");

	exit(0);
}

void dowake(int argc, char **argv)
{
	int shmid, tmp, *f;

	shmid = shmget(23, 4, IPC_CREAT|0666);
	SYSERROR(shmid, "shmget");

	f = shmat(shmid, NULL, 0);
	SYSERROR(f, "shmat");

	(*f)++;
	printf("WAKE: %p{%x}\n", f, *f);
	tmp = futex(f, FUTEX_WAKE, 1, NULL, NULL, 0);
	SYSERROR(tmp, "futex");
	printf("WOKE: %d\n", tmp);

	tmp = shmdt(f);
	SYSERROR(tmp, "shmdt");

	exit(0);
}

void badfutex(int argc, char **argv)
{
	int *x;
	int tmp;

	x = mmap(NULL, 16384, PROT_READ, MAP_PRIVATE|MAP_ANON, -1, 0);
	SYSERROR(x, "mmap");

	tmp = futex(x, FUTEX_WAIT, 0, NULL, NULL, 0);
	SYSERROR(tmp, "futex");
	exit(0);
}

/*
 * allocate a mapping that will be shaved by the mmap alloc shrinker
 */
void doshave(int argc, char **argv)
{
	void *x;

	x = mmap(NULL, 16384*16+1, PROT_READ, MAP_PRIVATE|MAP_ANON, -1, 0);
	SYSERROR(x, "mmap");
	exit(0);
}

int main(int argc, char **argv)
{
	if (argc <= 1)
		format();

	argc--;
	argv++;

	printf("Command: %s\n", argv[0]);

	if (strcmp(argv[0], "sysv") == 0)
		dosysvshm(argc, argv);

	if (strcmp(argv[0], "badfutex") == 0)
		badfutex(argc, argv);

	if (strcmp(argv[0], "chr") == 0)
		chardev(argc, argv);

	if (strcmp(argv[0], "posix") == 0)
		doposixshm(argc, argv);

	if (strcmp(argv[0], "remap") == 0)
		doremap(argc, argv);

	if (strcmp(argv[0], "shrink") == 0)
		doshrinkmmap(argc, argv);

	if (strcmp(argv[0], "file") == 0) {
		if (argc < 2)
			format();
		argv++;
		argc--;
		doxmmap(argc, argv, argv[0]);
	}

	if (strcmp(argv[0], "zero") == 0)
		doxmmap(argc, argv, "/dev/zero");

	if (strcmp(argv[0], "null") == 0)
		doxmmap(argc, argv, "/dev/null");

	if (strcmp(argv[0], "mtd") == 0)
		doxmmap(argc, argv, "/dev/mtd0");

	if (strcmp(argv[0], "wait") == 0)
		dowait(argc, argv);

	if (strcmp(argv[0], "wake") == 0)
		dowake(argc, argv);

	if (strcmp(argv[0], "shave") == 0)
		doshave(argc, argv);

	fprintf(stderr, "Unknown command\n");
	exit(1);
}