proc.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 *  proc.c
 *
 *  Copyright (C) 1995, 1996 by Paal-Kr. Engstad and Volker Lendecke
 *  Copyright (C) 1997 by Volker Lendecke
 *
 *  Please add a note about your changes to smbfs in the ChangeLog file.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/malloc.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/dcache.h>
#include <linux/dirent.h>
#include <linux/nls.h>

#include <linux/smb_fs.h>
#include <linux/smbno.h>
#include <linux/smb_mount.h>

#include <asm/string.h>

#include "smb_debug.h"


/* Features. Undefine if they cause problems, this should perhaps be a
   config option. */
#define SMBFS_POSIX_UNLINK 1

/* Allow smb_retry to be interrupted. Not sure of the benefit ... */
/* #define SMB_RETRY_INTR */

#define SMB_VWV(packet)  ((packet) + SMB_HEADER_LEN)
#define SMB_CMD(packet)  (*(packet+8))
#define SMB_WCT(packet)  (*(packet+SMB_HEADER_LEN - 1))
#define SMB_BCC(packet)  smb_bcc(packet)
#define SMB_BUF(packet)  ((packet) + SMB_HEADER_LEN + SMB_WCT(packet) * 2 + 2)

#define SMB_DIRINFO_SIZE 43
#define SMB_STATUS_SIZE  21

static int
smb_proc_setattr_ext(struct smb_sb_info *, struct inode *,
		     struct smb_fattr *);
static int
smb_proc_setattr_core(struct smb_sb_info *server, struct dentry *dentry,
                      __u16 attr);
static int
smb_proc_do_getattr(struct smb_sb_info *server, struct dentry *dir,
		    struct smb_fattr *fattr);


static inline void
smb_lock_server(struct smb_sb_info *server)
{
	down(&(server->sem));
}

static inline void
smb_unlock_server(struct smb_sb_info *server)
{
	up(&(server->sem));
}


static void
str_upper(char *name, int len)
{
	while (len--)
	{
		if (*name >= 'a' && *name <= 'z')
			*name -= ('a' - 'A');
		name++;
	}
}

static void
str_lower(char *name, int len)
{
	while (len--)
	{
		if (*name >= 'A' && *name <= 'Z')
			*name += ('a' - 'A');
		name++;
	}
}

/* reverse a string inline. This is used by the dircache walking routines */
static void reverse_string(char *buf, int len)
{
	char c;
	char *end = buf+len-1;

	while(buf < end) {
		c = *buf;
		*(buf++) = *end;
		*(end--) = c;
	}
}

/* no conversion, just a wrapper for memcpy. */
static int convert_memcpy(char *output, int olen,
			  const char *input, int ilen,
			  struct nls_table *nls_from,
			  struct nls_table *nls_to)
{
	memcpy(output, input, ilen);
	return ilen;
}

/* convert from one "codepage" to another (possibly being utf8). */
static int convert_cp(char *output, int olen,
		      const char *input, int ilen,
		      struct nls_table *nls_from,
		      struct nls_table *nls_to)
{
	int len = 0;
	int n;
	wchar_t ch;

	if (!nls_from || !nls_to) {
		PARANOIA("nls_from=%p, nls_to=%p\n", nls_from, nls_to);
		return convert_memcpy(output, olen, input, ilen, NULL, NULL);
	}

	while (ilen > 0) {
		/* convert by changing to unicode and back to the new cp */
		n = nls_from->char2uni((unsigned char *)input, ilen, &ch);
		if (n < 0)
			goto out;
		input += n;
		ilen -= n;

		n = nls_to->uni2char(ch, output, olen);
		if (n < 0)
			goto out;
		output += n;
		olen -= n;

		len += n;
	}
out:
	return len;
}

static int setcodepage(struct smb_sb_info *server,
		       struct nls_table **p, char *name)
{
	struct nls_table *nls;

	if (!name || !*name) {
		nls = NULL;
	} else if ( (nls = load_nls(name)) == NULL) {
		printk (KERN_ERR "smbfs: failed to load nls '%s'\n", name);
		return -EINVAL;
	}

	/* if already set, unload the previous one. */
	if (*p)
		unload_nls(*p);
	*p = nls;

	return 0;
}

/* Handles all changes to codepage settings. */
int smb_setcodepage(struct smb_sb_info *server, struct smb_nls_codepage *cp)
{
	int n;

	smb_lock_server(server);

	n = setcodepage(server, &server->local_nls, cp->local_name);
	if (n != 0)
		goto out;
	n = setcodepage(server, &server->remote_nls, cp->remote_name);
	if (n != 0)
		setcodepage(server, &server->local_nls, NULL);

out:
	if (server->local_nls != NULL && server->remote_nls != NULL)
		server->convert = convert_cp;
	else
		server->convert = convert_memcpy;

	smb_unlock_server(server);
	return n;
}


/*****************************************************************************/
/*                                                                           */
/*  Encoding/Decoding section                                                */
/*                                                                           */
/*****************************************************************************/

__u8 *
smb_encode_smb_length(__u8 * p, __u32 len)
{
	*p = 0;
	*(p+1) = 0;
	*(p+2) = (len & 0xFF00) >> 8;
	*(p+3) = (len & 0xFF);
	if (len > 0xFFFF)
	{
		*(p+1) = 1;
	}
	return p + 4;
}

/*
 * smb_build_path: build the path to entry and name storing it in buf.
 * The path returned will have the trailing '\0'.
 */
static int smb_build_path(struct smb_sb_info *server, char * buf,
			  struct dentry * entry, struct qstr * name)
{
	char *path = buf;
	int len;

	if (entry == NULL)
		goto test_name_and_out;

	/*
	 * If IS_ROOT, we have to do no walking at all.
	 */
	if (IS_ROOT(entry)) {
		*(path++) = '\\';
		if (name != NULL)
			goto name_and_out;
		goto out;
	}

	/*
	 * Build the path string walking the tree backward from end to ROOT
	 * and store it in reversed order [see reverse_string()]
	 */
	for (;;) {
		if (entry->d_name.len > SMB_MAXNAMELEN)
			return -ENAMETOOLONG;
		if (path - buf + entry->d_name.len > SMB_MAXPATHLEN)
			return -ENAMETOOLONG;

		len = server->convert(path, SMB_MAXNAMELEN, 
				      entry->d_name.name, entry->d_name.len,
				      server->local_nls, server->remote_nls);
		reverse_string(path, len);
		path += len;

		*(path++) = '\\';

		entry = entry->d_parent;

		if (IS_ROOT(entry))
			break;
	}

	reverse_string(buf, path-buf);

test_name_and_out:
	if (name != NULL) {
		*(path++) = '\\';
name_and_out:
		len = server->convert(path, SMB_MAXNAMELEN, 
				      name->name, name->len,
				      server->local_nls, server->remote_nls);
		path += len;
	}
out:
	*(path++) = '\0';
	return (path-buf);
}

static int smb_encode_path(struct smb_sb_info *server, char *buf,
			   struct dentry *dir, struct qstr *name)
{
	int result;

	result = smb_build_path(server, buf, dir, name);
	if (result < 0)
		goto out;
	if (server->opt.protocol <= SMB_PROTOCOL_COREPLUS)
		str_upper(buf, result);
out:
	return result;
}

/* The following are taken directly from msdos-fs */

/* Linear day numbers of the respective 1sts in non-leap years. */

static int day_n[] =
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0};
		  /* JanFebMarApr May Jun Jul Aug Sep Oct Nov Dec */


static time_t
utc2local(struct smb_sb_info *server, time_t time)
{
	return time - server->opt.serverzone*60;
}

static time_t
local2utc(struct smb_sb_info *server, time_t time)
{
	return time + server->opt.serverzone*60;
}

/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */

static time_t
date_dos2unix(struct smb_sb_info *server, __u16 date, __u16 time)
{
	int month, year;
	time_t secs;

	month = ((date >> 5) & 15) - 1;
	year = date >> 9;
	secs = (time & 31) * 2 + 60 * ((time >> 5) & 63) + (time >> 11) * 3600 + 86400 *
	    ((date & 31) - 1 + day_n[month] + (year / 4) + year * 365 - ((year & 3) == 0 &&
						   month < 2 ? 1 : 0) + 3653);
	/* days since 1.1.70 plus 80's leap day */
	return local2utc(server, secs);
}


/* Convert linear UNIX date to a MS-DOS time/date pair. */

static void
date_unix2dos(struct smb_sb_info *server,
	      int unix_date, __u16 *date, __u16 *time)
{
	int day, year, nl_day, month;

	unix_date = utc2local(server, unix_date);
	*time = (unix_date % 60) / 2 +
		(((unix_date / 60) % 60) << 5) +
		(((unix_date / 3600) % 24) << 11);

	day = unix_date / 86400 - 3652;
	year = day / 365;
	if ((year + 3) / 4 + 365 * year > day)
		year--;
	day -= (year + 3) / 4 + 365 * year;
	if (day == 59 && !(year & 3)) {
		nl_day = day;
		month = 2;
	} else {
		nl_day = (year & 3) || day <= 59 ? day : day - 1;
		for (month = 0; month < 12; month++)
			if (day_n[month] > nl_day)
				break;
	}
	*date = nl_day - day_n[month - 1] + 1 + (month << 5) + (year << 9);
}

/*****************************************************************************/
/*                                                                           */
/*  Support section.                                                         */
/*                                                                           */
/*****************************************************************************/

__u32
smb_len(__u8 * p)
{
	return ((*(p+1) & 0x1) << 16L) | (*(p+2) << 8L) | *(p+3);
}

static __u16
smb_bcc(__u8 * packet)
{
	int pos = SMB_HEADER_LEN + SMB_WCT(packet) * sizeof(__u16);
	return WVAL(packet, pos);
}

/* smb_valid_packet: We check if packet fulfills the basic
   requirements of a smb packet */

static int
smb_valid_packet(__u8 * packet)
{
	return (packet[4] == 0xff
		&& packet[5] == 'S'
		&& packet[6] == 'M'
		&& packet[7] == 'B'
		&& (smb_len(packet) + 4 == SMB_HEADER_LEN
		    + SMB_WCT(packet) * 2 + SMB_BCC(packet)));
}

/* smb_verify: We check if we got the answer we expected, and if we
   got enough data. If bcc == -1, we don't care. */

static int
smb_verify(__u8 * packet, int command, int wct, int bcc)
{
	if (SMB_CMD(packet) != command)
		goto bad_command;
	if (SMB_WCT(packet) < wct)
		goto bad_wct;
	if (bcc != -1 && SMB_BCC(packet) < bcc)
		goto bad_bcc;
	return 0;

bad_command:
	printk(KERN_ERR "smb_verify: command=%x, SMB_CMD=%x??\n",
	       command, SMB_CMD(packet));
	goto fail;
bad_wct:
	printk(KERN_ERR "smb_verify: command=%x, wct=%d, SMB_WCT=%d??\n",
	       command, wct, SMB_WCT(packet));
	goto fail;
bad_bcc:
	printk(KERN_ERR "smb_verify: command=%x, bcc=%d, SMB_BCC=%d??\n",
	       command, bcc, SMB_BCC(packet));
fail:
	return -EIO;
}

/*
 * Returns the maximum read or write size for the current packet size
 * and max_xmit value.
 * N.B. Since this value is usually computed before locking the server,
 * the server's packet size must never be decreased!
 */
static int
smb_get_xmitsize(struct smb_sb_info *server, int overhead)
{
	int size = server->packet_size;

	/*
	 * Start with the smaller of packet size and max_xmit ...
	 */
	if (size > server->opt.max_xmit)
		size = server->opt.max_xmit;
	return size - overhead;
}

/*
 * Calculate the maximum read size
 */
int
smb_get_rsize(struct smb_sb_info *server)
{
	int overhead = SMB_HEADER_LEN + 5 * sizeof(__u16) + 2 + 1 + 2;
	int size = smb_get_xmitsize(server, overhead);

	VERBOSE("packet=%d, xmit=%d, size=%d\n",
		server->packet_size, server->opt.max_xmit, size);

	return size;
}

/*
 * Calculate the maximum write size
 */
int
smb_get_wsize(struct smb_sb_info *server)
{
	int overhead = SMB_HEADER_LEN + 5 * sizeof(__u16) + 2 + 1 + 2;
	int size = smb_get_xmitsize(server, overhead);

	VERBOSE("packet=%d, xmit=%d, size=%d\n",
		server->packet_size, server->opt.max_xmit, size);

	return size;
}

int
smb_errno(struct smb_sb_info *server)
{
	int errcls = server->rcls;
	int error  = server->err;
	char *class = "Unknown";

	VERBOSE("errcls %d  code %d  from command 0x%x\n",
		errcls, error, SMB_CMD(server->packet));

	if (errcls == ERRDOS)
		switch (error)
		{
		case ERRbadfunc:
			return EINVAL;
		case ERRbadfile:
		case ERRbadpath:
			return ENOENT;
		case ERRnofids:
			return EMFILE;
		case ERRnoaccess:
			return EACCES;
		case ERRbadfid:
			return EBADF;
		case ERRbadmcb:
			return EREMOTEIO;
		case ERRnomem:
			return ENOMEM;
		case ERRbadmem:
			return EFAULT;
		case ERRbadenv:
		case ERRbadformat:
			return EREMOTEIO;
		case ERRbadaccess:
			return EACCES;
		case ERRbaddata:
			return E2BIG;
		case ERRbaddrive:
			return ENXIO;
		case ERRremcd:
			return EREMOTEIO;
		case ERRdiffdevice:
			return EXDEV;
		case ERRnofiles:	/* Why is this mapped to 0?? */
			return 0;
		case ERRbadshare:
			return ETXTBSY;
		case ERRlock:
			return EDEADLK;
		case ERRfilexists:
			return EEXIST;
		case 87:		/* should this map to 0?? */
			return 0;	/* Unknown error!! */
		case 123:		/* Invalid name?? e.g. .tmp* */
			return ENOENT;
		case 145:		/* Win NT 4.0: non-empty directory? */
			return ENOTEMPTY;
			/* This next error seems to occur on an mv when
			 * the destination exists */
		case 183:
			return EEXIST;
		default:
			class = "ERRDOS";
			goto err_unknown;
	} else if (errcls == ERRSRV)
		switch (error)
		{
		/* N.B. This is wrong ... EIO ? */
		case ERRerror:
			return ENFILE;
		case ERRbadpw:
			return EINVAL;
		case ERRbadtype:
			return EIO;
		case ERRaccess:
			return EACCES;
		/*
		 * This is a fatal error, as it means the "tree ID"
		 * for this connection is no longer valid. We map
		 * to a special error code and get a new connection.
		 */
		case ERRinvnid:
			return EBADSLT;
		default:
			class = "ERRSRV";
			goto err_unknown;
	} else if (errcls == ERRHRD)
		switch (error)
		{
		case ERRnowrite:
			return EROFS;
		case ERRbadunit:
			return ENODEV;
		case ERRnotready:
			return EUCLEAN;
		case ERRbadcmd:
		case ERRdata:
			return EIO;
		case ERRbadreq:
			return ERANGE;
		case ERRbadshare:
			return ETXTBSY;
		case ERRlock:
			return EDEADLK;
		default:
			class = "ERRHRD";
			goto err_unknown;
	} else if (errcls == ERRCMD)
		class = "ERRCMD";

err_unknown:
	printk(KERN_ERR "smb_errno: class %s, code %d from command 0x%x\n",
	       class, error, SMB_CMD(server->packet));
	return EIO;
}

/*
 * smb_retry: This function should be called when smb_request_ok has
 * indicated an error. If the error was indicated because the
 * connection was killed, we try to reconnect. If smb_retry returns 0,
 * the error was indicated for another reason, so a retry would not be
 * of any use.
 * N.B. The server must be locked for this call.
 */
static int
smb_retry(struct smb_sb_info *server)
{
	pid_t pid = server->conn_pid;
	int error, result = 0;

	if (server->state != CONN_INVALID)
		goto out;