#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <fcntl.h>

struct state
{
    const char **cmd;
    int fd;
    const char *path;
};


static void
do_one_command(const char *cmd, struct state *state)
{
    if (!strcmp(cmd, "unlink"))
    {
	fprintf(stderr, "dangle: unlink\n");
	unlink(state->path);
    }
    else if (!strncmp(cmd, "write", 5))
    {
	const char *data;

	data = cmd+5;
	if (!*data)
	    data = "X";
	fprintf(stderr, "dangle: write(\"%s\")\n", data);
	write(state->fd, data, strlen(data));
    }
    else if (!strcmp(cmd, "fsync"))
    {
	fprintf(stderr, "dangle: fsync\n");
	fsync(state->fd);
    }
    else if (!strcmp(cmd, "fdatasync"))
    {
	fprintf(stderr, "dangle: fdatasync\n");
	fdatasync(state->fd);
    }
    else if (!strcmp(cmd, "sigpause"))
    {
	fprintf(stderr, "dangle: sigpause\n");
	sigpause(0);
    }
    else if (!strncmp(cmd, "loop", 4))
    {
	int i, N;

	N = atoi(cmd+4);
	fprintf(stderr, "dangle: looping, N=%d\n", N);
	state->cmd++;
	if (N == 0)
	{
	    for (;;)
		do_one_command(*state->cmd, state);
	}
	else
	{
	    for (i = 0 ; i < N ; i++)
		do_one_command(*state->cmd, state);
	}
    }
    else
    {
	fprintf(stderr, "dangle: unknown command \"%s\"\n", cmd);
	exit(1);
    }
}


static void
do_commands(struct state *state)
{
    for ( ; *state->cmd != NULL ; state->cmd++)
    {
	do_one_command(*state->cmd, state);
    }
}



int
main(int argc, char **argv)
{
    struct state state;

    if (argc < 2)
    {
	fprintf(stderr, "Usage: dangle filename [command...]\n");
	exit(1);
    }
    state.path = argv[1];
    state.cmd = (const char **)argv+2;

    fprintf(stderr, "dangle: open(\"%s\")\n", state.path);
    state.fd = open(state.path, O_RDWR|O_CREAT, 0);
    if (state.fd < 0)
    {
	perror(state.path);
	exit(1);
    }

    do_commands(&state);

    fprintf(stderr, "dangle: exiting\n");
    return 0;
}