C++ os_close_file函数代码示例

static void slirp_close(int fd, void *data)
{
	struct slirp_data *pri = data;
	int status,err;

	os_close_file(fd);
	os_close_file(pri->slave);

	pri->slave = -1;

	if(pri->pid<1) {
		printk("slirp_close: no child process to shut down\n");
		return;
	}

#if 0
	if(kill(pri->pid, SIGHUP)<0) {
		printk("slirp_close: sending hangup to %d failed (%d)\n",
			pri->pid, errno);
	}
#endif

	CATCH_EINTR(err = waitpid(pri->pid, &status, WNOHANG));
	if(err < 0) {
		printk("slirp_close: waitpid returned %d\n", errno);
		return;
	}

	if(err == 0) {
		printk("slirp_close: process %d has not exited\n", pri->pid);
		return;
	}

	pri->pid = -1;
}

unsigned long os_process_pc(int pid)
{
	char proc_stat[STAT_PATH_LEN], buf[256];
	unsigned long pc;
	int fd, err;

	sprintf(proc_stat, "/proc/%d/stat", pid);
	fd = os_open_file(proc_stat, of_read(OPENFLAGS()), 0);
	if(fd < 0){
		printk("os_process_pc - couldn't open '%s', err = %d\n",
		       proc_stat, -fd);
		return(ARBITRARY_ADDR);
	}
	err = os_read_file(fd, buf, sizeof(buf));
	if(err < 0){
		printk("os_process_pc - couldn't read '%s', err = %d\n",
		       proc_stat, -err);
		os_close_file(fd);
		return(ARBITRARY_ADDR);
	}
	os_close_file(fd);
	pc = ARBITRARY_ADDR;
	if(sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
		  "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
		  "%*d %*d %*d %*d %*d %lu", &pc) != 1){
		printk("os_process_pc - couldn't find pc in '%s'\n", buf);
	}
	return(pc);
}

static int slirp_open(void *data)
{
	struct slirp_data *pri = data;
	int fds[2], pid, err;

	err = os_pipe(fds, 1, 1);
	if(err)
		return(err);

	err = slirp_tramp(pri->argw.argv, fds[1]);
	if(err < 0){
		printk("slirp_tramp failed - errno = %d\n", -err);
		goto out;
	}
	pid = err;

	pri->slave = fds[1];
	pri->slip.pos = 0;
	pri->slip.esc = 0;
	pri->pid = err;

	return(fds[0]);
out:
	os_close_file(fds[0]);
	os_close_file(fds[1]);
	return err;
}

static void etap_pre_exec(void *arg)
{
	struct etap_pre_exec_data *data = arg;

	dup2(data->control_remote, 1);
	os_close_file(data->data_me);
	os_close_file(data->control_me);
}

static void daemon_remove(void *data)
{
	struct daemon_data *pri = data;

	os_close_file(pri->fd);
	os_close_file(pri->control);
	kfree(pri->data_addr);
	kfree(pri->ctl_addr);
	kfree(pri->local_addr);
}

static int slip_tramp(char **argv, int fd)
{
	struct slip_pre_exec_data pe_data;
	char *output;
	int status, pid, fds[2], err, output_len;

	err = os_pipe(fds, 1, 0);
	if(err < 0){
		printk("slip_tramp : pipe failed, err = %d\n", -err);
		goto out;
	}

	err = 0;
	pe_data.stdin = fd;
	pe_data.stdout = fds[1];
	pe_data.close_me = fds[0];
	err = run_helper(slip_pre_exec, &pe_data, argv, NULL);
	if(err < 0)
		goto out_close;
	pid = err;

	output_len = page_size();
	output = um_kmalloc(output_len);
	if(output == NULL){
		printk("slip_tramp : failed to allocate output buffer\n");
		os_kill_process(pid, 1);
		err = -ENOMEM;
		goto out_free;
	}

	os_close_file(fds[1]);
	read_output(fds[0], output, output_len);
	printk("%s", output);

	CATCH_EINTR(err = waitpid(pid, &status, 0));
	if(err < 0)
		err = errno;
	else if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0)){
		printk("'%s' didn't exit with status 0\n", argv[0]);
		err = -EINVAL;
	}
	else err = 0;

	os_close_file(fds[0]);

out_free:
	kfree(output);
	return err;

out_close:
	os_close_file(fds[0]);
	os_close_file(fds[1]);
out:
	return err;
}

static void pre_exec(void *d)
{
	struct dog_data *data = d;

	dup2(data->stdin, 0);
	dup2(data->stdout, 1);
	dup2(data->stdout, 2);
	os_close_file(data->stdin);
	os_close_file(data->stdout);
	os_close_file(data->close_me[0]);
	os_close_file(data->close_me[1]);
}

static void etap_close(int fd, void *data)
{
	struct ethertap_data *pri = data;

	iter_addresses(pri->dev, etap_close_addr, &pri->control_fd);
	os_close_file(fd);
	os_shutdown_socket(pri->data_fd, 1, 1);
	os_close_file(pri->data_fd);
	pri->data_fd = -1;
	os_close_file(pri->control_fd);
	pri->control_fd = -1;
}

int os_process_parent(int pid)
{
	char stat[STAT_PATH_LEN];
	char data[256];
	int parent, n, fd;

	if(pid == -1) return(-1);

	snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
	fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
	if(fd < 0){
		printk("Couldn't open '%s', err = %d\n", stat, -fd);
		return(FAILURE_PID);
	}

	n = os_read_file(fd, data, sizeof(data));
	os_close_file(fd);

	if(n < 0){
		printk("Couldn't read '%s', err = %d\n", stat, -n);
		return(FAILURE_PID);
	}

	parent = FAILURE_PID;
	n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
	if(n != 1)
		printk("Failed to scan '%s'\n", data);

	return(parent);
}

static void change_pre_exec(void *arg)
{
	struct change_pre_exec_data *data = arg;

	os_close_file(data->close_me);
	dup2(data->stdout, 1);
}

void file_close(file_t* file)
{
    u32 i;
    cache_entry_t* entry;
    
    /* Unmap cached pages. */
    for (i = 0; i < CACHE_SIZE; i++) {
        entry = &file->cache.entries[i];
        if (entry->ptr != NULL) {
            if (entry->ref > 0) {
                fprintf(stderr, "file_close: unmapping used page %u (%p)\n",
                        entry->pageid, entry->ptr);
            }
            
            DPRINT("file_close: unmapping cached page %u (%p)\n",
                   entry->pageid, entry->ptr);
            if (os_put_page(file->handle, entry->ptr) == 0)
                file->stats.unmapped++;
        }
    }
    
#if !defined(NSTATS)
    file_dump_info(file);
#endif /* !defined(NSTATS) */

    /* Unmap the header page. */
    os_put_page(file->handle, file->header);

    /* Close the file. */
    os_close_file(file->handle);

    /* Free the file object. */
    memset(file, 0, sizeof(file_t));
    free(file);
}

void destroy_context(struct mm_struct *mm)
{
	struct mm_context *mmu = &mm->context;

	if (proc_mm)
		os_close_file(mmu->id.u.mm_fd);
	else {
		/*
		 * If init_new_context wasn't called, this will be
		 * zero, resulting in a kill(0), which will result in the
		 * whole UML suddenly dying.  Also, cover negative and
		 * 1 cases, since they shouldn't happen either.
		 */
		if (mmu->id.u.pid < 2) {
			printk(KERN_ERR "corrupt mm_context - pid = %d\n",
			       mmu->id.u.pid);
			return;
		}
		os_kill_ptraced_process(mmu->id.u.pid, 1);
	}

	if (skas_needs_stub)
		free_page(mmu->id.stack);

	free_ldt(mmu);
}

static int file_removed(struct dentry *dentry, const char *file)
{
	char *host_file;
	int extra, fd;

	extra = 0;
	if(file != NULL) extra += strlen(file) + 1;

	host_file = dentry_name(dentry, extra + strlen("/remove"));
	if(host_file == NULL){
		printk("file_removed : allocation failed\n");
		return(-ENOMEM);
	}

	if(file != NULL){
		strcat(host_file, "/");
		strcat(host_file, file);
	}
	strcat(host_file, "/remove");

	fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
	kfree(host_file);
	if(fd >= 0){
		os_close_file(fd);
		return(1);
	}
	return(0);
}

unsigned long os_process_pc(int pid)
{
	char proc_stat[STAT_PATH_LEN], buf[256];
	unsigned long pc = ARBITRARY_ADDR;
	int fd, err;

	sprintf(proc_stat, "/proc/%d/stat", pid);
	fd = open(proc_stat, O_RDONLY, 0);
	if (fd < 0) {
		printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
		       "errno = %d\n", proc_stat, errno);
		goto out;
	}
	CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
	if (err < 0) {
		printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
		       "err = %d\n", proc_stat, errno);
		goto out_close;
	}
	os_close_file(fd);
	pc = ARBITRARY_ADDR;
	if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
		   "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
		   "%*d %*d %*d %*d %*d %lu", &pc) != 1)
		printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
		       buf);
 out_close:
	close(fd);
 out:
	return pc;
}

static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
			     char *buffer, int buffer_len, int *used_out)
{
	struct tuntap_pre_exec_data data;
	char version_buf[sizeof("nnnnn\0")];
	char *argv[] = { "uml_net", version_buf, "tuntap", "up", gate,
			 NULL };
	char buf[CMSG_SPACE(sizeof(*fd_out))];
	struct msghdr msg;
	struct cmsghdr *cmsg;
	struct iovec iov;
	int pid, n, err;

	sprintf(version_buf, "%d", UML_NET_VERSION);

	data.stdout = remote;
	data.close_me = me;

	pid = run_helper(tuntap_pre_exec, &data, argv, NULL);

	if(pid < 0) return(-pid);

	os_close_file(remote);

	msg.msg_name = NULL;
	msg.msg_namelen = 0;
	if(buffer != NULL){
		iov = ((struct iovec) { buffer, buffer_len });