searchlink.c

操作系统SunOS 4.1.3版本的源码

#ifndef lint
static char sccsid[] = "@(#)searchlink.c 1.1 92/07/30 Copyr 1988 Sun Micro";
#endif

/*
 * Copyright (c) 1987 Sun Microsystems, Inc.
 */

/*
 * Library routines to read/write .tfs_info files, which contain
 * searchlinks, backlinks, and whiteout information.  These routines
 * are called by the tfsd and by preserve, which creates rev-trees
 * behind the tfsd's back, and so needs to look at .tfs_info files
 * directly.
 */

#include <nse/stdio.h>
#include <strings.h>
#include <errno.h>
#include <sys/stat.h>
#include <nse/param.h>
#include <nse/util.h>
#include <nse/searchlink.h>
#include <nse/file_err.h>

#define STRIP_EOLN(string)	string[strlen(string) - 1] = '\0';

static Nse_err	tfs_file_move();
static Nse_err	tfs_file_read();
static Nse_err	do_file_read();
static Nse_err	tfs_file_write();
static Nse_err	write_tfs_file_contents();
static Nse_err	tfs_fgets();


/*
 * Returns the searchlink of 'directory' in the string 'name' (which should
 * be MAXPATHLEN chars long.)  If there is no searchlink for the directory,
 * ENOENT is returned as the error code.
 */
Nse_err
nse_get_searchlink(directory, name)
	char		*directory;
	char		*name;
{
	Nse_err		result;

	result = tfs_file_read(directory, name,
				(int *) NULL, (Nse_whiteout *) NULL,
				(Nse_whiteout *) NULL, (FILE **) NULL);
	if ((result == NULL) && (name[0] == '\0')) {
		errno = ENOENT;
		result = nse_err_format_errno("Tfs read of searchlink in directory \"%s\"", 
		    directory);
	}
	return (result);
}


/*
 * Set searchlink of 'directory' to 'name', regardless of whether or not a
 * searchlink already exists for 'directory'.
 */
Nse_err
nse_set_searchlink(directory, name)
	char		*directory;
	char		*name;
{
	FILE		*file;
	char		old_link[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	wo;
	Nse_err		result;

	if (result = tfs_file_read(directory, old_link, &blct, &bl,
				   &wo, &file)) {
		return (result);
	}
	result = tfs_file_write(directory, name, blct, bl, wo, file);
	nse_dispose_whiteout(bl);
	nse_dispose_whiteout(wo);
	return (result);
}


/*
 * Set the searchlink of 'directory' to 'name' only if 'directory' does not
 * already have a searchlink.  An error code is returned in two cases:
 * either the directory already has a searchlink which has a value
 * different from 'name', in which case NSE_SL_ALREADY_SET_DIFF is
 * returned and 'old_name' contains the old searchlink; or an error
 * occurred, in which case the intro(2) error code is returned.
 *
 * The boolean pointed at by `changedp' is set to indicate if the
 * searchlink changed.
 */
Nse_err
nse_set_cond_searchlink(directory, name, old_name, changedp)
	char		*directory;
	char		*name;
	char		*old_name;
	bool_t		*changedp;
{
	FILE		*file;
	Nse_whiteout	wo;
	int		blct;
	Nse_whiteout	bl;
	Nse_err		result;

	*changedp = FALSE;
	if (result = tfs_file_read(directory, old_name, &blct, &bl,
				   &wo, &file)) {
		return (result);
	}
	if (old_name[0] != '\0') {
		fclose(file);
		if (!NSE_STREQ(name, old_name)) {
			result = nse_err_format(NSE_SL_ALREADY_SET_DIFF,
						directory);
		}
	} else {
		*changedp = TRUE;
		result = tfs_file_write(directory, name, blct, bl, wo, file);
	}
	nse_dispose_whiteout(bl);
	nse_dispose_whiteout(wo);
	return (result);
}

/*
 * Returns list of white-out entries in directory.
 */
Nse_err
nse_get_whiteout(directory, wop)
	char		*directory;
	Nse_whiteout	*wop;
{
	char		searchlink[MAXPATHLEN];

	return tfs_file_read(directory, searchlink, (int *) NULL,
				(Nse_whiteout *) NULL, wop, (FILE **) NULL);
}


/*
 * Set a new whiteout entry 'name' in 'directory'.  This function is a
 * no-op if whiteout entry 'name' is already set for the directory.
 */
Nse_err
nse_set_whiteout(directory, name)
	char		*directory;
	char		*name;
{
	FILE		*file;
	char		searchlink[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	wo_first;
	Nse_whiteout	wo;
	int		found = 0;
	Nse_err		result;

	if (result = tfs_file_read(directory, searchlink, &blct,
					&bl, &wo_first, &file)) {
		return (result);
	}

	wo = wo_first;
	while (wo != NULL) {
		if (NSE_STREQ(name, wo->name)) {
			found = 1;
			break;
		}
		wo = wo->next;
	}
	if (found) {
		fclose(file);
	} else {
		wo = NSE_NEW(Nse_whiteout);
		wo->name = NSE_STRDUP(name);
		wo->next = wo_first;
		wo_first = wo;
		result = tfs_file_write(directory, searchlink, blct, bl,
						wo_first, file);
	}
	nse_dispose_whiteout(bl);
	nse_dispose_whiteout(wo_first);
	return (result);
}


/*
 * Clear whiteout entry 'name' from the whiteout list of 'directory'.  If
 * 'name' is not in the whiteout list of 'directory', 0 is returned.
 */
Nse_err
nse_clear_whiteout(directory, name)
	char		*directory;
	char		*name;
{
	FILE		*file;
	char		searchlink[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	wo_first;
	Nse_whiteout	wo;
	Nse_whiteout	wo_prev = NULL;
	int		found = 0;
	Nse_err		result;

	if (result = tfs_file_read(directory, searchlink, &blct,
					&bl, &wo_first, &file)) {
		return (result);
	}

	wo = wo_first;
	while (wo != NULL) {
		if (NSE_STREQ(name, wo->name)) {
			found = 1;
			break;
		}
		wo_prev = wo;
		wo = wo->next;
	}
	if (found) {
		if (wo_prev == NULL) {
			wo_first = wo->next;
		} else {
			wo_prev->next = wo->next;
		}
		free(wo->name);
		free((char *) wo);
		result = tfs_file_write(directory, searchlink,
					blct, bl, wo_first, file);
	} else {
		fclose(file);
	}
	nse_dispose_whiteout(bl);
	nse_dispose_whiteout(wo_first);
	return (result);
}

/*
 * Purge all whiteout info from a tfs file and replace search link.
 *
 */
Nse_err
nse_purge_whiteout(directory, newlink)
	char		*directory;
	char		*newlink;
{
	FILE		*file;
	char		searchlink[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	wo;
	Nse_err		result;

	if (result = tfs_file_read(directory, searchlink, &blct,
					&bl, &wo, &file)) {
		return result;
	}
	nse_dispose_whiteout(wo);
	result = tfs_file_write(directory, newlink,
					blct, bl, (Nse_whiteout) NULL, file);
	nse_dispose_whiteout(bl);
	return result;
}


/*
 * Release the list allocated by nse_get_whiteout.
 */
void
nse_dispose_whiteout(wo)
	Nse_whiteout	wo;
{
	Nse_whiteout	wo_next;

	while (wo != NULL) {
		wo_next = wo->next;
		free(wo->name);
		free((char *) wo);
		wo = wo_next;
	}
}


/*
 * Returns list of backlink entries in directory.
 */
Nse_err
nse_get_backlink(directory, blp)
	char		*directory;
	Nse_whiteout	*blp;
{
	char		searchlink[MAXPATHLEN];
	int		blct;

	return tfs_file_read(directory, searchlink, &blct, blp,
				(Nse_whiteout *) NULL, (FILE **) NULL);
}


/*
 * Set a new backlink entry 'name' in 'directory'.  This function is a
 * no-op if backlink entry 'name' is already set for the directory.
 */
Nse_err
nse_set_backlink(directory, name)
	char		*directory;
	char		*name;
{
	FILE		*file;
	char		searchlink[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	bl_first;
	Nse_whiteout	wo;
	int		found = 0;
	Nse_err		result;

	if (result = tfs_file_read(directory, searchlink, &blct,
					&bl_first, &wo, &file)) {
		return (result);
	}

	bl = bl_first;
	while (bl != NULL) {
		if (NSE_STREQ(name, bl->name)) {
			found = 1;
			break;
		}
		bl = bl->next;
	}
	if (found) {
		fclose(file);
	} else {
		bl = NSE_NEW(Nse_whiteout);
		bl->name = NSE_STRDUP(name);
		bl->next = bl_first;
		bl_first = bl;
		blct++;
		result = tfs_file_write(directory, searchlink, blct, bl_first,
						wo, file);
	}
	nse_dispose_whiteout(bl_first);
	nse_dispose_whiteout(wo);
	return (result);
}


/*
 * Clear backlink entry 'name' from the backlink list of 'directory'.  If
 * 'name' is not in the backlink list of 'directory', 0 is returned.
 */
Nse_err
nse_clear_backlink(directory, name)
	char		*directory;
	char		*name;
{
	FILE		*file;
	char		searchlink[MAXPATHLEN];
	int		blct;
	Nse_whiteout	bl;
	Nse_whiteout	bl_first;
	Nse_whiteout	wo;
	Nse_whiteout	bl_prev = NULL;
	int		found = 0;
	Nse_err		result;

	if (result = tfs_file_read(directory, searchlink, &blct,
					&bl_first, &wo, &file)) {
		return (result);
	}

	bl = bl_first;
	while (bl != NULL) {
		if (NSE_STREQ(name, bl->name)) {
			found = 1;
			break;
		}
		bl_prev = bl;
		bl = bl->next;
	}
	if (found) {
		if (bl_prev == NULL) {
			bl_first = bl->next;
		} else {
			bl_prev->next = bl->next;
		}
		free(bl->name);
		free((char *) bl);
		blct--;
		result = tfs_file_write(directory, searchlink,
					blct, bl_first, wo, file);
	} else {
		fclose(file);
	}
	nse_dispose_whiteout(bl_first);
	nse_dispose_whiteout(wo);
	return (result);
}


static FILE	*tfs_info_file;

/*
 * Return both the searchlink, backlink, and the white-out entries in
 * 'directory'.
 */
Nse_err
nse_get_tfs_info(directory, name, blp, wop, will_write_later)
	char		*directory;
	char		*name;
	Nse_whiteout	*blp;
	Nse_whiteout	*wop;
	bool_t		will_write_later;
{
	FILE		**filep;
	int		blct;

	if (will_write_later) {
		filep = &tfs_info_file;
	} else {
		filep = NULL;
	}
	return tfs_file_read(directory, name, &blct, blp, wop, filep);
}


/*
 * Set all tfs info for 'directory'.
 */
Nse_err
nse_set_tfs_info(directory, name, bl_first, wo)
	char		*directory;
	char		*name;
	Nse_whiteout	bl_first;
	Nse_whiteout	wo;
{
	int		blct = 0;