util_file.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/*
 * Unix SMB/CIFS implementation.
 * SMB parameters and setup
 * Copyright (C) Andrew Tridgell 1992-1998 Modified by Jeremy Allison 1995.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 675
 * Mass Ave, Cambridge, MA 02139, USA.
 */

#include "includes.h"

#ifndef MAP_FAILED
#define MAP_FAILED ((void *)-1)
#endif

static int gotalarm;

/***************************************************************
 Signal function to tell us we timed out.
****************************************************************/

static void gotalarm_sig(void)
{
	gotalarm = 1;
}

/***************************************************************
 Lock or unlock a fd for a known lock type. Abandon after waitsecs 
 seconds.
****************************************************************/

BOOL do_file_lock(int fd, int waitsecs, int type)
{
	SMB_STRUCT_FLOCK lock;
	int             ret;
	void (*oldsig_handler)(int);

	gotalarm = 0;
	oldsig_handler = CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);

	lock.l_type = type;
	lock.l_whence = SEEK_SET;
	lock.l_start = 0;
	lock.l_len = 1;
	lock.l_pid = 0;

	alarm(waitsecs);
	/* Note we must *NOT* use sys_fcntl here ! JRA */
	ret = fcntl(fd, SMB_F_SETLKW, &lock);
	alarm(0);
	CatchSignal(SIGALRM, SIGNAL_CAST oldsig_handler);

	if (gotalarm) {
		DEBUG(0, ("do_file_lock: failed to %s file.\n",
			type == F_UNLCK ? "unlock" : "lock"));
		return False;
	}

	return (ret == 0);
}

/***************************************************************
 Lock an fd. Abandon after waitsecs seconds.
****************************************************************/

BOOL file_lock(int fd, int type, int secs, int *plock_depth)
{
	if (fd < 0)
		return False;

	(*plock_depth)++;

	if ((*plock_depth) == 0) {
		if (!do_file_lock(fd, secs, type)) {
			DEBUG(10,("file_lock: locking file failed, error = %s.\n", strerror(errno)));
			return False;
		}
	}

	return True;
}

/***************************************************************
 Unlock an fd. Abandon after waitsecs seconds.
****************************************************************/

BOOL file_unlock(int fd, int *plock_depth)
{
	BOOL ret=True;

	if(*plock_depth == 1) {
		ret = do_file_lock(fd, 5, F_UNLCK);
	}

	(*plock_depth)--;

	if(!ret) {
		DEBUG(10,("file_unlock: unlocking file failed, error = %s.\n", strerror(errno)));
	}
	return ret;
}

/***************************************************************
 Locks a file for enumeration / modification.
 update to be set = True if modification is required.
****************************************************************/

void *startfilepwent(char *pfile, char *s_readbuf, int bufsize,
				int *file_lock_depth, BOOL update)
{
	FILE *fp = NULL;

	if (!*pfile) {
		DEBUG(0, ("startfilepwent: No file set\n"));
		return (NULL);
	}
	DEBUG(10, ("startfilepwent: opening file %s\n", pfile));

	fp = sys_fopen(pfile, update ? "r+b" : "rb");

	if (fp == NULL) {
		DEBUG(0, ("startfilepwent: unable to open file %s\n", pfile));
		return NULL;
	}

	/* Set a buffer to do more efficient reads */
	setvbuf(fp, s_readbuf, _IOFBF, bufsize);

	if (!file_lock(fileno(fp), (update ? F_WRLCK : F_RDLCK), 5, file_lock_depth)) {
		DEBUG(0, ("startfilepwent: unable to lock file %s\n", pfile));
		fclose(fp);
		return NULL;
	}

	/* Make sure it is only rw by the owner */
	chmod(pfile, 0600);

	/* We have a lock on the file. */
	return (void *)fp;
}

/***************************************************************
 End enumeration of the file.
****************************************************************/

void endfilepwent(void *vp, int *file_lock_depth)
{
	FILE *fp = (FILE *)vp;

	file_unlock(fileno(fp), file_lock_depth);
	fclose(fp);
	DEBUG(7, ("endfilepwent: closed file.\n"));
}

/*************************************************************************
 Return the current position in the file list as an SMB_BIG_UINT.
 This must be treated as an opaque token.
*************************************************************************/

SMB_BIG_UINT getfilepwpos(void *vp)
{
	return (SMB_BIG_UINT)sys_ftell((FILE *)vp);
}

/*************************************************************************
 Set the current position in the file list from an SMB_BIG_UINT.
 This must be treated as an opaque token.
*************************************************************************/

BOOL setfilepwpos(void *vp, SMB_BIG_UINT tok)
{
	return !sys_fseek((FILE *)vp, (SMB_OFF_T)tok, SEEK_SET);
}

/*************************************************************************
 Gets a line out of a file.
 line is of format "xxxx:xxxxxx:xxxxx:".
 lines with "#" at the front are ignored.
*************************************************************************/

int getfileline(void *vp, char *linebuf, int linebuf_size)
{
	/* Static buffers we will return. */
	FILE *fp = (FILE *)vp;
	unsigned char   c;
	unsigned char  *p;
	size_t linebuf_len;

	if (fp == NULL) {
		DEBUG(0,("getfileline: Bad file pointer.\n"));
		return -1;
	}

	/*
	 * Scan the file, a line at a time.
	 */
	while (!feof(fp)) {
		linebuf[0] = '\0';

		fgets(linebuf, linebuf_size, fp);
		if (ferror(fp)) {
			return -1;
		}

		/*
		 * Check if the string is terminated with a newline - if not
		 * then we must keep reading and discard until we get one.
		 */

		linebuf_len = strlen(linebuf);
		if (linebuf_len == 0) {
			linebuf[0] = '\0';
			return 0;
		}

		if (linebuf[linebuf_len - 1] != '\n') {
			c = '\0';
			while (!ferror(fp) && !feof(fp)) {
				c = fgetc(fp);
				if (c == '\n') {
					break;
				}
			}
		} else {
			linebuf[linebuf_len - 1] = '\0';
		}

#ifdef DEBUG_PASSWORD
		DEBUG(100, ("getfileline: got line |%s|\n", linebuf));
#endif
		if ((linebuf[0] == 0) && feof(fp)) {
			DEBUG(4, ("getfileline: end of file reached\n"));
			return 0;
		}

		if (linebuf[0] == '#' || linebuf[0] == '\0') {
			DEBUG(6, ("getfileline: skipping comment or blank line\n"));
			continue;
		}

		p = (unsigned char *) strchr_m(linebuf, ':');
		if (p == NULL) {
			DEBUG(0, ("getfileline: malformed line entry (no :)\n"));
			continue;
		}
		return linebuf_len;
	}
	return -1;
}

/****************************************************************************
 Read a line from a file with possible \ continuation chars. 
 Blanks at the start or end of a line are stripped.
 The string will be allocated if s2 is NULL.
****************************************************************************/

char *fgets_slash(char *s2,int maxlen,XFILE *f)
{
	char *s=s2;
	int len = 0;
	int c;
	BOOL start_of_line = True;

	if (x_feof(f)) {
		return(NULL);
	}

	if (maxlen <2) {
		return(NULL);
	}

	if (!s2) {
		maxlen = MIN(maxlen,8);
		s = (char *)SMB_MALLOC(maxlen);
	}

	if (!s) {
		return(NULL);
	}

	*s = 0;

	while (len < maxlen-1) {
		c = x_getc(f);
		switch (c) {
			case '\r':
				break;
			case '\n':
				while (len > 0 && s[len-1] == ' ') {
					s[--len] = 0;
				}
				if (len > 0 && s[len-1] == '\\') {
					s[--len] = 0;
					start_of_line = True;
					break;
				}
				return(s);
			case EOF:
				if (len <= 0 && !s2)  {
					SAFE_FREE(s);
				}
				return(len>0?s:NULL);
			case ' ':
				if (start_of_line) {
					break;
				}
			default:
				start_of_line = False;
				s[len++] = c;
				s[len] = 0;
		}

		if (!s2 && len > maxlen-3) {
			char *t;
	  
			maxlen *= 2;
			t = (char *)SMB_REALLOC(s,maxlen);
			if (!t) {
				DEBUG(0,("fgets_slash: failed to expand buffer!\n"));
				SAFE_FREE(s);
				return(NULL);
			} else {
				s = t;
			}
		}
	}
	return(s);
}

/****************************************************************************
 Load from a pipe into memory.
****************************************************************************/

char *file_pload(char *syscmd, size_t *size)
{
	int fd, n;
	char *p, *tp;
	pstring buf;
	size_t total;
	
	fd = sys_popen(syscmd);
	if (fd == -1) {
		return NULL;
	}

	p = NULL;
	total = 0;

	while ((n = read(fd, buf, sizeof(buf))) > 0) {
		tp = SMB_REALLOC(p, total + n + 1);
		if (!tp) {
		        DEBUG(0,("file_pload: failed to expand buffer!\n"));
			close(fd);
			SAFE_FREE(p);
			return NULL;
		} else {
			p = tp;
		}
		memcpy(p+total, buf, n);
		total += n;
	}
	if (p) p[total] = 0;

	/* FIXME: Perhaps ought to check that the command completed
	 * successfully (returned 0); if not the data may be
	 * truncated. */
	sys_pclose(fd);

	if (size) {
		*size = total;
	}

	return p;
}

/****************************************************************************
 Load a file into memory from a fd.
****************************************************************************/ 

char *fd_load(int fd, size_t *size)
{
	SMB_STRUCT_STAT sbuf;
	char *p;

	if (sys_fstat(fd, &sbuf) != 0) {
		return NULL;
	}

	p = (char *)SMB_MALLOC(sbuf.st_size+1);
	if (!p) {
		return NULL;
	}

	if (read(fd, p, sbuf.st_size) != sbuf.st_size) {
		SAFE_FREE(p);
		return NULL;
	}
	p[sbuf.st_size] = 0;

	if (size) {
		*size = sbuf.st_size;
	}

	return p;
}

/****************************************************************************
 Load a file into memory.
****************************************************************************/

char *file_load(const char *fname, size_t *size)
{
	int fd;
	char *p;

	if (!fname || !*fname) {
		return NULL;
	}
	
	fd = open(fname,O_RDONLY);
	if (fd == -1) {
		return NULL;
	}

	p = fd_load(fd, size);
	close(fd);
	return p;
}

/*******************************************************************
 mmap (if possible) or read a file.
********************************************************************/

void *map_file(char *fname, size_t size)
{
	size_t s2 = 0;
	void *p = NULL;
#ifdef HAVE_MMAP
	int fd;
	fd = open(fname, O_RDONLY, 0);
	if (fd == -1) {
		DEBUG(2,("map_file: Failed to load %s - %s\n", fname, strerror(errno)));
		return NULL;
	}
	p = mmap(NULL, size, PROT_READ, MAP_SHARED|MAP_FILE, fd, 0);
	close(fd);
	if (p == MAP_FAILED) {
		DEBUG(1,("map_file: Failed to mmap %s - %s\n", fname, strerror(errno)));
		return NULL;
	}
#endif
	if (!p) {
		p = file_load(fname, &s2);
		if (!p) {
			return NULL;
		}
		if (s2 != size) {
			DEBUG(1,("map_file: incorrect size for %s - got %lu expected %lu\n",
				 fname, (unsigned long)s2, (unsigned long)size));
			SAFE_FREE(p);	
			return NULL;
		}
	}
	return p;
}

/****************************************************************************
 Parse a buffer into lines.
****************************************************************************/

static char **file_lines_parse(char *p, size_t size, int *numlines)
{
	int i;
	char *s, **ret;

	if (!p) {
		return NULL;
	}

	for (s = p, i=0; s < p+size; s++) {
		if (s[0] == '\n') i++;
	}

	ret = SMB_MALLOC_ARRAY(char *, i+2);
	if (!ret) {
		SAFE_FREE(p);
		return NULL;
	}	
	memset(ret, 0, sizeof(ret[0])*(i+2));
	if (numlines) {
		*numlines = i;
	}

	ret[0] = p;
	for (s = p, i=0; s < p+size; s++) {
		if (s[0] == '\n') {
			s[0] = 0;
			i++;
			ret[i] = s+1;
		}
		if (s[0] == '\r') {
			s[0] = 0;
		}
	}

	return ret;
}

/****************************************************************************
 Load a file into memory and return an array of pointers to lines in the file
 must be freed with file_lines_free(). 
****************************************************************************/

char **file_lines_load(const char *fname, int *numlines)
{
	char *p;
	size_t size = 0;

	p = file_load(fname, &size);
	if (!p) {
		return NULL;
	}

	return file_lines_parse(p, size, numlines);
}

/****************************************************************************
 Load a fd into memory and return an array of pointers to lines in the file
 must be freed with file_lines_free(). If convert is true calls unix_to_dos on
 the list.
****************************************************************************/

char **fd_lines_load(int fd, int *numlines)
{
	char *p;
	size_t size;

	p = fd_load(fd, &size);
	if (!p) {
		return NULL;
	}

	return file_lines_parse(p, size, numlines);
}

/****************************************************************************
 Load a pipe into memory and return an array of pointers to lines in the data
 must be freed with file_lines_free(). 
****************************************************************************/

char **file_lines_pload(char *syscmd, int *numlines)
{
	char *p;
	size_t size;

	p = file_pload(syscmd, &size);
	if (!p) {
		return NULL;
	}

	return file_lines_parse(p, size, numlines);
}

/****************************************************************************
 Free lines loaded with file_lines_load.
****************************************************************************/

void file_lines_free(char **lines)
{
	if (!lines) {
		return;
	}
	SAFE_FREE(lines[0]);
	SAFE_FREE(lines);
}

/****************************************************************************
 Take a list of lines and modify them to produce a list where \ continues
 a line.
****************************************************************************/

void file_lines_slashcont(char **lines)
{
	int i, j;

	for (i=0; lines[i];) {
		int len = strlen(lines[i]);
		if (lines[i][len-1] == '\\') {
			lines[i][len-1] = ' ';
			if (lines[i+1]) {
				char *p = &lines[i][len];
				while (p < lines[i+1]) {
					*p++ = ' ';
				}
				for (j = i+1; lines[j]; j++) {
					lines[j] = lines[j+1];
				}
			}
		} else {
			i++;
		}
	}
}

/****************************************************************************
 Save a lump of data into a file. Mostly used for debugging.
****************************************************************************/

BOOL file_save(const char *fname, void *packet, size_t length)
{
	int fd;
	fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644);
	if (fd == -1) {
		return False;
	}
	if (write(fd, packet, length) != (size_t)length) {
		return False;
	}
	close(fd);
	return True;
}