text: // SPDX-License-Identifier: GPL-2.0
  /*
   * linux/drivers/scsi/scsi_proc.c
   *
   * The functions in this file provide an interface between
   * the PROC file system and the SCSI device drivers
   * It is mainly used for debugging, statistics and to pass 
   * information directly to the lowlevel driver.
   *
   * (c) 1995 Michael Neuffer neuffer@goofy.zdv.uni-mainz.de 
   * Version: 0.99.8   last change: 95/09/13
   * 
   * generic command parser provided by: 
   * Andreas Heilwagen <crashcar@informatik.uni-koblenz.de>
   *
   * generic_proc_info() support of xxxx_info() by:
   * Michael A. Griffith <grif@acm.org>
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/string.h>
  #include <linux/mm.h>
  #include <linux/proc_fs.h>
  #include <linux/errno.h>
  #include <linux/blkdev.h>
  #include <linux/seq_file.h>
  #include <linux/mutex.h>
  #include <linux/gfp.h>
  #include <linux/uaccess.h>
  
  #include <scsi/scsi.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_host.h>
  #include <scsi/scsi_transport.h>
  
  #include "scsi_priv.h"
  #include "scsi_logging.h"
  
  
  /* 4K page size, but our output routines, use some slack for overruns */
  #define PROC_BLOCK_SIZE (3*1024)
  
  static struct proc_dir_entry *proc_scsi;
  
  /* Protect sht->present and sht->proc_dir */
  static DEFINE_MUTEX(global_host_template_mutex);
  
  static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf,
                             size_t count, loff_t *ppos)
  {
  	struct Scsi_Host *shost = PDE_DATA(file_inode(file));
  	ssize_t ret = -ENOMEM;
  	char *page;
      
  	if (count > PROC_BLOCK_SIZE)
  		return -EOVERFLOW;
  
  	if (!shost->hostt->write_info)
  		return -EINVAL;
  
  	page = (char *)__get_free_page(GFP_KERNEL);
  	if (page) {
  		ret = -EFAULT;
  		if (copy_from_user(page, buf, count))
  			goto out;
  		ret = shost->hostt->write_info(shost, page, count);
  	}
  out:
  	free_page((unsigned long)page);
  	return ret;
  }
  
  static int proc_scsi_show(struct seq_file *m, void *v)
  {
  	struct Scsi_Host *shost = m->private;
  	return shost->hostt->show_info(m, shost);
  }
  
  static int proc_scsi_host_open(struct inode *inode, struct file *file)
  {
  	return single_open_size(file, proc_scsi_show, PDE_DATA(inode),
  				4 * PAGE_SIZE);
  }
  
  static const struct file_operations proc_scsi_fops = {
  	.open = proc_scsi_host_open,
  	.release = single_release,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.write = proc_scsi_host_write
  };
  
  /**
   * scsi_proc_hostdir_add - Create directory in /proc for a scsi host
   * @sht: owner of this directory
   *
   * Sets sht->proc_dir to the new directory.
   */
  
  void scsi_proc_hostdir_add(struct scsi_host_template *sht)
  {
  	if (!sht->show_info)
  		return;
  
  	mutex_lock(&global_host_template_mutex);
  	if (!sht->present++) {
  		sht->proc_dir = proc_mkdir(sht->proc_name, proc_scsi);
          	if (!sht->proc_dir)
  			printk(KERN_ERR "%s: proc_mkdir failed for %s\n",
  			       __func__, sht->proc_name);
  	}
  	mutex_unlock(&global_host_template_mutex);
  }
  
  /**
   * scsi_proc_hostdir_rm - remove directory in /proc for a scsi host
   * @sht: owner of directory
   */
  void scsi_proc_hostdir_rm(struct scsi_host_template *sht)
  {
  	if (!sht->show_info)
  		return;
  
  	mutex_lock(&global_host_template_mutex);
  	if (!--sht->present && sht->proc_dir) {
  		remove_proc_entry(sht->proc_name, proc_scsi);
  		sht->proc_dir = NULL;
  	}
  	mutex_unlock(&global_host_template_mutex);
  }
  
  
  /**
   * scsi_proc_host_add - Add entry for this host to appropriate /proc dir
   * @shost: host to add
   */
  void scsi_proc_host_add(struct Scsi_Host *shost)
  {
  	struct scsi_host_template *sht = shost->hostt;
  	struct proc_dir_entry *p;
  	char name[10];
  
  	if (!sht->proc_dir)
  		return;
  
  	sprintf(name,"%d", shost->host_no);
  	p = proc_create_data(name, S_IRUGO | S_IWUSR,
  		sht->proc_dir, &proc_scsi_fops, shost);
  	if (!p)
  		printk(KERN_ERR "%s: Failed to register host %d in"
  		       "%s\n", __func__, shost->host_no,
  		       sht->proc_name);
  }
  
  /**
   * scsi_proc_host_rm - remove this host's entry from /proc
   * @shost: which host
   */
  void scsi_proc_host_rm(struct Scsi_Host *shost)
  {
  	char name[10];
  
  	if (!shost->hostt->proc_dir)
  		return;
  
  	sprintf(name,"%d", shost->host_no);
  	remove_proc_entry(name, shost->hostt->proc_dir);
  }
  
  /**
   * proc_print_scsidevice - return data about this host
   * @dev: A scsi device
   * @data: &struct seq_file to output to.
   *
   * Description: prints Host, Channel, Id, Lun, Vendor, Model, Rev, Type,
   * and revision.
   */
  static int proc_print_scsidevice(struct device *dev, void *data)
  {
  #ifdef CONFIG_HISI_DEBUG_FS
  	struct scsi_device *sdev;
  	struct seq_file *s = data;
  	int i;
  
  	if (!scsi_is_sdev_device(dev))
  		goto out;
  
  	sdev = to_scsi_device(dev);
  	seq_printf(s,
  		"Host: scsi%d Channel: %02d Id: %02d Lun: %02llu\n  Vendor: ",
  		sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);
  	for (i = 0; i < 8; i++) {
  		if (sdev->vendor[i] >= 0x20)
  			seq_putc(s, sdev->vendor[i]);
  		else
  			seq_putc(s, ' ');
  	}
  
  	seq_puts(s, " Model: ");
  	for (i = 0; i < 16; i++) {
  		if (sdev->model[i] >= 0x20)
  			seq_putc(s, sdev->model[i]);
  		else
  			seq_putc(s, ' ');
  	}
  
  	seq_puts(s, " Rev: ");
  	for (i = 0; i < 4; i++) {
  		if (sdev->rev[i] >= 0x20)
  			seq_putc(s, sdev->rev[i]);
  		else
  			seq_putc(s, ' ');
  	}
  
  	seq_putc(s, '\n');
  
  	seq_printf(s, "  Type:   %s ", scsi_device_type(sdev->type));
  	seq_printf(s, "               ANSI  SCSI revision: %02x",
  			sdev->scsi_level - (sdev->scsi_level > 1));
  	if (sdev->scsi_level == 2)
  		seq_puts(s, " CCS\n");
  	else
  		seq_putc(s, '\n');
  
  out:
  #endif
  	return 0;
  }
  
  /**
   * scsi_add_single_device - Respond to user request to probe for/add device
   * @host: user-supplied decimal integer
   * @channel: user-supplied decimal integer
   * @id: user-supplied decimal integer
   * @lun: user-supplied decimal integer
   *
   * Description: called by writing "scsi add-single-device" to /proc/scsi/scsi.
   *
   * does scsi_host_lookup() and either user_scan() if that transport
   * type supports it, or else scsi_scan_host_selected()
   *
   * Note: this seems to be aimed exclusively at SCSI parallel busses.
   */
  
  static int scsi_add_single_device(uint host, uint channel, uint id, uint lun)
  {
  	struct Scsi_Host *shost;
  	int error = -ENXIO;
  
  	shost = scsi_host_lookup(host);
  	if (!shost)
  		return error;
  
  	if (shost->transportt->user_scan)
  		error = shost->transportt->user_scan(shost, channel, id, lun);
  	else
  		error = scsi_scan_host_selected(shost, channel, id, lun,
  						SCSI_SCAN_MANUAL);
  	scsi_host_put(shost);
  	return error;
  }
  
  /**
   * scsi_remove_single_device - Respond to user request to remove a device
   * @host: user-supplied decimal integer
   * @channel: user-supplied decimal integer
   * @id: user-supplied decimal integer
   * @lun: user-supplied decimal integer
   *
   * Description: called by writing "scsi remove-single-device" to
   * /proc/scsi/scsi.  Does a scsi_device_lookup() and scsi_remove_device()
   */
  static int scsi_remove_single_device(uint host, uint channel, uint id, uint lun)
  {
  	struct scsi_device *sdev;
  	struct Scsi_Host *shost;
  	int error = -ENXIO;
  
  	shost = scsi_host_lookup(host);
  	if (!shost)
  		return error;
  	sdev = scsi_device_lookup(shost, channel, id, lun);
  	if (sdev) {
  		scsi_remove_device(sdev);
  		scsi_device_put(sdev);
  		error = 0;
  	}
  
  	scsi_host_put(shost);
  	return error;
  }
  
  /**
   * proc_scsi_write - handle writes to /proc/scsi/scsi
   * @file: not used
   * @buf: buffer to write
   * @length: length of buf, at most PAGE_SIZE
   * @ppos: not used
   *
   * Description: this provides a legacy mechanism to add or remove devices by
   * Host, Channel, ID, and Lun.  To use,
   * "echo 'scsi add-single-device 0 1 2 3' > /proc/scsi/scsi" or
   * "echo 'scsi remove-single-device 0 1 2 3' > /proc/scsi/scsi" with
   * "0 1 2 3" replaced by the Host, Channel, Id, and Lun.
   *
   * Note: this seems to be aimed at parallel SCSI. Most modern busses (USB,
   * SATA, Firewire, Fibre Channel, etc) dynamically assign these values to
   * provide a unique identifier and nothing more.
   */
  
  
  static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
  			       size_t length, loff_t *ppos)
  {
  	int host, channel, id, lun;
  	char *buffer, *p;
  	int err;
  
  	if (!buf || length > PAGE_SIZE)
  		return -EINVAL;
  
  	buffer = (char *)__get_free_page(GFP_KERNEL);
  	if (!buffer)
  		return -ENOMEM;
  
  	err = -EFAULT;
  	if (copy_from_user(buffer, buf, length))
  		goto out;
  
  	err = -EINVAL;
  	if (length < PAGE_SIZE)
  		buffer[length] = '\0';
  	else if (buffer[PAGE_SIZE-1])
  		goto out;
  
  	/*
  	 * Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
  	 * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
  	 */
  	if (!strncmp("scsi add-single-device", buffer, 22)) {
  		p = buffer + 23;
  
  		host = simple_strtoul(p, &p, 0);
  		channel = simple_strtoul(p + 1, &p, 0);
  		id = simple_strtoul(p + 1, &p, 0);
  		lun = simple_strtoul(p + 1, &p, 0);
  
  		err = scsi_add_single_device(host, channel, id, lun);
  
  	/*
  	 * Usage: echo "scsi remove-single-device 0 1 2 3" >/proc/scsi/scsi
  	 * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
  	 */
  	} else if (!strncmp("scsi remove-single-device", buffer, 25)) {
  		p = buffer + 26;
  
  		host = simple_strtoul(p, &p, 0);
  		channel = simple_strtoul(p + 1, &p, 0);
  		id = simple_strtoul(p + 1, &p, 0);
  		lun = simple_strtoul(p + 1, &p, 0);
  
  		err = scsi_remove_single_device(host, channel, id, lun);
  	}
  
  	/*
  	 * convert success returns so that we return the 
  	 * number of bytes consumed.
  	 */
  	if (!err)
  		err = length;
  
   out:
  	free_page((unsigned long)buffer);
  	return err;
  }
  
  static int always_match(struct device *dev, void *data)
  {
  	return 1;
  }
  
  static inline struct device *next_scsi_device(struct device *start)
  {
  	struct device *next = bus_find_device(&scsi_bus_type, start, NULL,
  					      always_match);
  	put_device(start);
  	return next;
  }
  
  static void *scsi_seq_start(struct seq_file *sfile, loff_t *pos)
  {
  	struct device *dev = NULL;
  	loff_t n = *pos;
  
  	while ((dev = next_scsi_device(dev))) {
  		if (!n--)
  			break;
  		sfile->private++;
  	}
  	return dev;
  }
  
  static void *scsi_seq_next(struct seq_file *sfile, void *v, loff_t *pos)
  {
  	(*pos)++;
  	sfile->private++;
  	return next_scsi_device(v);
  }
  
  static void scsi_seq_stop(struct seq_file *sfile, void *v)
  {
  	put_device(v);
  }
  
  static int scsi_seq_show(struct seq_file *sfile, void *dev)
  {
  	if (!sfile->private)
  		seq_puts(sfile, "Attached devices:\n");
  
  	return proc_print_scsidevice(dev, sfile);
  }
  
  static const struct seq_operations scsi_seq_ops = {
  	.start	= scsi_seq_start,
  	.next	= scsi_seq_next,
  	.stop	= scsi_seq_stop,
  	.show	= scsi_seq_show
  };
  
  /**
   * proc_scsi_open - glue function
   * @inode: not used
   * @file: passed to single_open()
   *
   * Associates proc_scsi_show with this file
   */
  static int proc_scsi_open(struct inode *inode, struct file *file)
  {
  	/*
  	 * We don't really need this for the write case but it doesn't
  	 * harm either.
  	 */
  	return seq_open(file, &scsi_seq_ops);
  }
  
  static const struct file_operations proc_scsi_operations = {
  	.owner		= THIS_MODULE,
  	.open		= proc_scsi_open,
  	.read		= seq_read,
  	.write		= proc_scsi_write,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  
  /**
   * scsi_init_procfs - create scsi and scsi/scsi in procfs
   */
  int __init scsi_init_procfs(void)
  {
  	struct proc_dir_entry *pde;
  
  	proc_scsi = proc_mkdir("scsi", NULL);
  	if (!proc_scsi)
  		goto err1;
  
  	pde = proc_create("scsi/scsi", 0, NULL, &proc_scsi_operations);
  	if (!pde)
  		goto err2;
  
  	return 0;
  
  err2:
  	remove_proc_entry("scsi", NULL);
  err1:
  	return -ENOMEM;
  }
  
  /**
   * scsi_exit_procfs - Remove scsi/scsi and scsi from procfs
   */
  void scsi_exit_procfs(void)
  {
  	remove_proc_entry("scsi/scsi", NULL);
  	remove_proc_entry("scsi", NULL);
  }
  