#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
struct ioctl_gntdev_grant_ref {
	/* The domain ID of the grant to be mapped. */
	uint32_t domid;
	/* The grant reference of the grant to be mapped. */
	uint32_t ref;
};

/*
 * Allocates a new page and creates a new grant reference.
 */
#define IOCTL_GNTALLOC_ALLOC_GREF \
_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
struct ioctl_gntalloc_alloc_gref {
	/* IN parameters */
	/* The ID of the domain to be given access to the grants. */
	uint16_t domid;
	/* Flags for this mapping */
	uint16_t flags;
	/* Number of pages to map */
	uint32_t count;
	/* OUT parameters */
	/* The offset to be used on a subsequent call to mmap(). */
	uint64_t index;
	/* The grant references of the newly created grant, one per page */
	/* Variable size, depending on count */
	uint32_t gref_ids[1];
};

#define GNTALLOC_FLAG_WRITABLE 1

/*
 * Deallocates the grant reference, allowing the associated page to be freed if
 * no other domains are using it.
 */
#define IOCTL_GNTALLOC_DEALLOC_GREF \
_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
struct ioctl_gntalloc_dealloc_gref {
	/* IN parameters */
	/* The offset returned in the map operation */
	uint64_t index;
	/* Number of references to unmap */
	uint32_t count;
};

#define IOCTL_GNTDEV_MAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
struct ioctl_gntdev_map_grant_ref {
    /* IN parameters */
    /* The number of grants to be mapped. */
    uint32_t count;
    uint32_t pad;
    /* OUT parameters */
    /* The offset to be used on a subsequent call to mmap(). */
    uint64_t index;
    /* Variable IN parameter. */
    /* Array of grant references, of size @count. */
    struct ioctl_gntdev_grant_ref refs[1];
};
#define GNTDEV_MAP_WRITABLE 0x1

#define IOCTL_GNTDEV_UNMAP_GRANT_REF \
_IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))       
struct ioctl_gntdev_unmap_grant_ref {
    /* IN parameters */
    /* The offset was returned by the corresponding map operation. */
    uint64_t index;
    /* The number of pages to be unmapped. */
    uint32_t count;
    uint32_t pad;
};


int a_fd;
int d_fd;

struct data {
	uint64_t* mem;
	int handle;
} items[128];

void sa(int id) {
	struct ioctl_gntalloc_alloc_gref arg = {
		.domid = id,
		.flags = GNTALLOC_FLAG_WRITABLE,
		.count = 1
	};
	int rv = ioctl(a_fd, IOCTL_GNTALLOC_ALLOC_GREF, &arg);
	if (rv)
		printf("src-add error: %s (rv=%d)\n", strerror(errno), rv);
	else {
		int i=0;
		while (items[i].mem) i++;
		items[i].mem = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, a_fd, arg.index);
		items[i].handle = arg.index;
		printf("src-add mapped %d at %d=%ld\n", arg.gref_ids[0], arg.index, items[i].mem);
	}
}

void sd(int ref) {
	struct ioctl_gntalloc_dealloc_gref arg = {
		.index = ref,
		.count = 1
	};

	int rv = ioctl(a_fd, IOCTL_GNTALLOC_DEALLOC_GREF, &arg);
	if (rv)
		printf("src-del error: %s (rv=%d)\n", strerror(errno), rv);
}

void mm(int domid, int refid) {
	struct ioctl_gntdev_map_grant_ref arg = {
		.count = 1,
		.refs[0].domid = domid,
		.refs[0].ref = refid,
	};
	int rv = ioctl(d_fd, IOCTL_GNTDEV_MAP_GRANT_REF, &arg);
	if (rv)
		printf("mm error: %s (rv=%d)\n", strerror(errno), rv);
	else {
		int i=0;
		while (items[i].mem) i++;
		items[i].mem = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, d_fd, arg.index);
		items[i].handle = arg.index;
		printf("mapped index %d at %ld\n", arg.index, items[i].mem);
	}
}

void gu(int index) {
	struct ioctl_gntdev_unmap_grant_ref arg = {
		.index = index,
		.count = 1,
	};
	int rv = ioctl(d_fd, IOCTL_GNTDEV_UNMAP_GRANT_REF, &arg);
	if (rv)
		printf("gu error: %s (rv=%d)\n", strerror(errno), rv);
}

void mu(void* addr) {
	int i = 0;
	munmap(addr, 4096);
	while (i < 128)
	{
		if (items[i].mem == addr)
			items[i].mem = 0;
		i++;
	}
}

int bump;

void show() {
	int i;
	for(i=0; i < 128; i++) {
		if (!items[i].mem)
			continue;
		uint64_t val = items[i].mem[0];
		uint64_t repl = val + bump;
		printf("%02d(%ld,%d): current %16lx   new %16lx\n", i, items[i].mem, items[i].handle, val, repl);
		items[i].mem[0] = repl;
	}
	printf("END\n");
}

int main(int argc, char** argv) {
	a_fd = open("/dev/xen/gntalloc", O_RDWR);
	d_fd = open("/dev/xen/gntdev", O_RDWR);
	bump = 1 << (2 * (getpid() % 12));
	printf(
		"src-add <domid>       return gntref, address\n"
		"map <domid> <ref>     return index, address\n"
		"src-del <gntref>      no rv\n"
		"gu <index>            no rv\n"
		"unmap <address>       no rv\n"
		"show                  print and change mapped items\n"
		" This process bumps by %x\n",
		bump
	);
	while (1) {
		char line[80];
		char word[30];
		long a, b;
		printf("\n> ");
		fflush(stdout);
		fgets(line, 80, stdin);
		sscanf(line, "%s %ld %ld", word, &a, &b);
		if (!strcmp(word, "src-add")) {
			sa(a);
		} else if (!strcmp(word, "src-del")) {
			sd(a);
		} else if (!strcmp(word, "map")) {
			mm(a, b);
		} else if (!strcmp(word, "gu")) {
			gu(a);
		} else if (!strcmp(word, "unmap")) {
			mu((void*)a);
		} else {
			show();
		}
	}
}