trunk/src/files.c

/***************************************
 $Header: /home/amb/CVS/routino/src/files.c,v 1.13 2009-09-17 12:41:21 amb Exp $

 Functions to map a file into memory.

 Part of the Routino routing software.
 ******************/ /******************
 This file Copyright 2008,2009 Andrew M. Bishop

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 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 Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***************************************/


#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/types.h>

#include "functions.h"


struct mmapinfo
{
 const char  *filename;
       int    fd;
       void  *address;
       size_t length;
};

struct mmapinfo *mappedfiles;
int nmappedfiles=0;


/*++++++++++++++++++++++++++++++++++++++
  Return a filename composed of the dirname, prefix and filename.

  char *FileName Returns an allocated filename.

  const char *dirname The directory name.

  const char *prefix The file prefix.

  const char *name The filename.
  ++++++++++++++++++++++++++++++++++++++*/

char *FileName(const char *dirname,const char *prefix, const char *name)
{
 char *filename=(char*)malloc((dirname?strlen(dirname):0)+1+(prefix?strlen(prefix):0)+1+strlen(name));

 sprintf(filename,"%s%s%s%s%s",dirname?dirname:"",dirname?"/":"",prefix?prefix:"",prefix?"-":"",name);

 return(filename);
}


/*++++++++++++++++++++++++++++++++++++++
  Open a file and map it into memory.

  void *MapFile Returns the address of the file.

  const char *filename The name of the file to open.
  ++++++++++++++++++++++++++++++++++++++*/

void *MapFile(const char *filename)
{
 int fd;
 struct stat buf;
 void *address;

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' to read.\n",filename);
    exit(EXIT_FAILURE);
   }

 /* Get the length of the file */

 if(fstat(fd,&buf))
   {
    close(fd);

    fprintf(stderr,"Cannot stat file '%s'.\n",filename);
    exit(EXIT_FAILURE);
   }

 /* Map the file */

 address=mmap(NULL,buf.st_size,PROT_READ,MAP_SHARED,fd,0);

 if(address==MAP_FAILED)
   {
    close(fd);

    fprintf(stderr,"Cannot mmap file '%s'.\n",filename);
    exit(EXIT_FAILURE);
   }

 mappedfiles=(struct mmapinfo*)realloc((void*)mappedfiles,(nmappedfiles+1)*sizeof(struct mmapinfo));

 mappedfiles[nmappedfiles].filename=filename;
 mappedfiles[nmappedfiles].fd=fd;
 mappedfiles[nmappedfiles].address=address;
 mappedfiles[nmappedfiles].length=buf.st_size;

 nmappedfiles++;

 return(address);
}


/*++++++++++++++++++++++++++++++++++++++
  Unmap a file and optionally delete it.

  Returns NULL (for similarity to the MapFile function).

  const char *filename The name of the file when it was opened.
  ++++++++++++++++++++++++++++++++++++++*/

void *UnmapFile(const char *filename)
{
 int i;

 for(i=0;i<nmappedfiles;i++)
    if(!strcmp(mappedfiles[i].filename,filename))
       break;

 if(i==nmappedfiles)
   {
    fprintf(stderr,"Cannot find file '%s' to unmap.\n",filename);
    exit(EXIT_FAILURE);
   }

 /* Close the file */

 close(mappedfiles[i].fd);

 /* Unmap the file */

 munmap(mappedfiles[i].address,mappedfiles[i].length);

 /* Shuffle the list of files */

 nmappedfiles--;

 if(nmappedfiles>i)
    memmove(&mappedfiles[i],&mappedfiles[i+1],(nmappedfiles-i)*sizeof(struct mmapinfo));

 return(NULL);
}


/*++++++++++++++++++++++++++++++++++++++
  Open a new file on disk for writing to.

  int OpenFile Returns the file descriptor if OK or something negative in case of an error.

  const char *filename The name of the file to create.
  ++++++++++++++++++++++++++++++++++++++*/

int OpenFile(const char *filename)
{
 int fd;

 /* Open the file */

 fd=open(filename,O_WRONLY|O_CREAT|O_TRUNC,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' to write.\n",filename);
    exit(EXIT_FAILURE);
   }

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Open an existing file on disk for reading from.

  int OpenFile Returns the file descriptor if OK or something negative in case of an error.

  const char *filename The name of the file to open.
  ++++++++++++++++++++++++++++++++++++++*/

int ReOpenFile(const char *filename)
{
 int fd;

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' to read.\n",filename);
    exit(EXIT_FAILURE);
   }

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Write data to a file on disk.

  int WriteFile Returns 0 if OK or something else in case of an error.

  int fd The file descriptor to write to.

  const void *address The address of the data to be written from.

  size_t length The length of data to write.
  ++++++++++++++++++++++++++++++++++++++*/

int WriteFile(int fd,const void *address,size_t length)
{
 /* Write the data */

 if(write(fd,address,length)!=length)
    return(-1);

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Read data from a file on disk.

  int ReadFile Returns 0 if OK or something else in case of an error.

  int fd The file descriptor to read from.

  void *address The address of the data to be read into.

  size_t length The length of data to read.
  ++++++++++++++++++++++++++++++++++++++*/

int ReadFile(int fd,void *address,size_t length)
{
 /* Read the data */

 if(read(fd,address,length)!=length)
    return(-1);

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Seek to a position in a file on disk.

  int SeekFile Returns 0 if OK or something else in case of an error.

  int fd The file descriptor to seek within.

  size_t position The position to seek to.
  ++++++++++++++++++++++++++++++++++++++*/

int SeekFile(int fd,size_t position)
{
 /* Seek the data */

 if(lseek(fd,position,SEEK_SET)!=position)
    return(-1);

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Close a file on disk.

  int fd The file descriptor to close.
  ++++++++++++++++++++++++++++++++++++++*/

void CloseFile(int fd)
{
 close(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Delete a file from disk.

  int DeleteFile Returns 0 if OK or something else in case of an error.

  char *filename The name of the file to delete.
  ++++++++++++++++++++++++++++++++++++++*/

int DeleteFile(char *filename)
{
 unlink(filename);

 return(0);
}
1	/***************************************
2	$Header: /home/amb/CVS/routino/src/files.c,v 1.13 2009-09-17 12:41:21 amb Exp $
3
4	Functions to map a file into memory.
5
6	Part of the Routino routing software.
7	****************/ /****************
8	This file Copyright 2008,2009 Andrew M. Bishop
9
10	This program is free software: you can redistribute it and/or modify
11	it under the terms of the GNU Affero General Public License as published by
12	the Free Software Foundation, either version 3 of the License, or
13	(at your option) any later version.
14
15	This program is distributed in the hope that it will be useful,
16	but WITHOUT ANY WARRANTY; without even the implied warranty of
17	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18	GNU Affero General Public License for more details.
19
20	You should have received a copy of the GNU Affero General Public License
21	along with this program. If not, see <http://www.gnu.org/licenses/>.
22	***************************************/
23
24
25	#include <unistd.h>
26	#include <stdlib.h>
27	#include <string.h>
28	#include <fcntl.h>
29	#include <sys/stat.h>
30	#include <sys/mman.h>
31	#include <sys/types.h>
32
33	#include "functions.h"
34
35
36	struct mmapinfo
37	{
38	const char *filename;
39	int fd;
40	void *address;
41	size_t length;
42	};
43
44	struct mmapinfo *mappedfiles;
45	int nmappedfiles=0;
46
47
48	/*++++++++++++++++++++++++++++++++++++++
49	Return a filename composed of the dirname, prefix and filename.
50
51	char *FileName Returns an allocated filename.
52
53	const char *dirname The directory name.
54
55	const char *prefix The file prefix.
56
57	const char *name The filename.
58	++++++++++++++++++++++++++++++++++++++*/
59
60	char FileName(const char dirname,const char prefix, const char name)
61	{
62	char filename=(char)malloc((dirname?strlen(dirname):0)+1+(prefix?strlen(prefix):0)+1+strlen(name));
63
64	sprintf(filename,"%s%s%s%s%s",dirname?dirname:"",dirname?"/":"",prefix?prefix:"",prefix?"-":"",name);
65
66	return(filename);
67	}
68
69
70	/*++++++++++++++++++++++++++++++++++++++
71	Open a file and map it into memory.
72
73	void *MapFile Returns the address of the file.
74
75	const char *filename The name of the file to open.
76	++++++++++++++++++++++++++++++++++++++*/
77
78	void MapFile(const char filename)
79	{
80	int fd;
81	struct stat buf;
82	void *address;
83
84	/* Open the file */
85
86	fd=open(filename,O_RDONLY);
87
88	if(fd<0)
89	{
90	fprintf(stderr,"Cannot open file '%s' to read.\n",filename);
91	exit(EXIT_FAILURE);
92	}
93
94	/* Get the length of the file */
95
96	if(fstat(fd,&buf))
97	{
98	close(fd);
99
100	fprintf(stderr,"Cannot stat file '%s'.\n",filename);
101	exit(EXIT_FAILURE);
102	}
103
104	/* Map the file */
105
106	address=mmap(NULL,buf.st_size,PROT_READ,MAP_SHARED,fd,0);
107
108	if(address==MAP_FAILED)
109	{
110	close(fd);
111
112	fprintf(stderr,"Cannot mmap file '%s'.\n",filename);
113	exit(EXIT_FAILURE);
114	}
115
116	mappedfiles=(struct mmapinfo)realloc((void)mappedfiles,(nmappedfiles+1)*sizeof(struct mmapinfo));
117
118	mappedfiles[nmappedfiles].filename=filename;
119	mappedfiles[nmappedfiles].fd=fd;
120	mappedfiles[nmappedfiles].address=address;
121	mappedfiles[nmappedfiles].length=buf.st_size;
122
123	nmappedfiles++;
124
125	return(address);
126	}
127
128
129	/*++++++++++++++++++++++++++++++++++++++
130	Unmap a file and optionally delete it.
131
132	Returns NULL (for similarity to the MapFile function).
133
134	const char *filename The name of the file when it was opened.
135	++++++++++++++++++++++++++++++++++++++*/
136
137	void UnmapFile(const char filename)
138	{
139	int i;
140
141	for(i=0;i<nmappedfiles;i++)
142	if(!strcmp(mappedfiles[i].filename,filename))
143	break;
144
145	if(i==nmappedfiles)
146	{
147	fprintf(stderr,"Cannot find file '%s' to unmap.\n",filename);
148	exit(EXIT_FAILURE);
149	}
150
151	/* Close the file */
152
153	close(mappedfiles[i].fd);
154
155	/* Unmap the file */
156
157	munmap(mappedfiles[i].address,mappedfiles[i].length);
158
159	/* Shuffle the list of files */
160
161	nmappedfiles--;
162
163	if(nmappedfiles>i)
164	memmove(&mappedfiles[i],&mappedfiles[i+1],(nmappedfiles-i)*sizeof(struct mmapinfo));
165
166	return(NULL);
167	}
168
169
170	/*++++++++++++++++++++++++++++++++++++++
171	Open a new file on disk for writing to.
172
173	int OpenFile Returns the file descriptor if OK or something negative in case of an error.
174
175	const char *filename The name of the file to create.
176	++++++++++++++++++++++++++++++++++++++*/
177
178	int OpenFile(const char *filename)
179	{
180	int fd;
181
182	/* Open the file */
183
184	fd=open(filename,O_WRONLY\|O_CREAT\|O_TRUNC,S_IRUSR\|S_IWUSR\|S_IRGRP\|S_IROTH);
185
186	if(fd<0)
187	{
188	fprintf(stderr,"Cannot open file '%s' to write.\n",filename);
189	exit(EXIT_FAILURE);
190	}
191
192	return(fd);
193	}
194
195
196	/*++++++++++++++++++++++++++++++++++++++
197	Open an existing file on disk for reading from.
198
199	int OpenFile Returns the file descriptor if OK or something negative in case of an error.
200
201	const char *filename The name of the file to open.
202	++++++++++++++++++++++++++++++++++++++*/
203
204	int ReOpenFile(const char *filename)
205	{
206	int fd;
207
208	/* Open the file */
209
210	fd=open(filename,O_RDONLY);
211
212	if(fd<0)
213	{
214	fprintf(stderr,"Cannot open file '%s' to read.\n",filename);
215	exit(EXIT_FAILURE);
216	}
217
218	return(fd);
219	}
220
221
222	/*++++++++++++++++++++++++++++++++++++++
223	Write data to a file on disk.
224
225	int WriteFile Returns 0 if OK or something else in case of an error.
226
227	int fd The file descriptor to write to.
228
229	const void *address The address of the data to be written from.
230
231	size_t length The length of data to write.
232	++++++++++++++++++++++++++++++++++++++*/
233
234	int WriteFile(int fd,const void *address,size_t length)
235	{
236	/* Write the data */
237
238	if(write(fd,address,length)!=length)
239	return(-1);
240
241	return(0);
242	}
243
244
245	/*++++++++++++++++++++++++++++++++++++++
246	Read data from a file on disk.
247
248	int ReadFile Returns 0 if OK or something else in case of an error.
249
250	int fd The file descriptor to read from.
251
252	void *address The address of the data to be read into.
253
254	size_t length The length of data to read.
255	++++++++++++++++++++++++++++++++++++++*/
256
257	int ReadFile(int fd,void *address,size_t length)
258	{
259	/* Read the data */
260
261	if(read(fd,address,length)!=length)
262	return(-1);
263
264	return(0);
265	}
266
267
268	/*++++++++++++++++++++++++++++++++++++++
269	Seek to a position in a file on disk.
270
271	int SeekFile Returns 0 if OK or something else in case of an error.
272
273	int fd The file descriptor to seek within.
274
275	size_t position The position to seek to.
276	++++++++++++++++++++++++++++++++++++++*/
277
278	int SeekFile(int fd,size_t position)
279	{
280	/* Seek the data */
281
282	if(lseek(fd,position,SEEK_SET)!=position)
283	return(-1);
284
285	return(0);
286	}
287
288
289	/*++++++++++++++++++++++++++++++++++++++
290	Close a file on disk.
291
292	int fd The file descriptor to close.
293	++++++++++++++++++++++++++++++++++++++*/
294
295	void CloseFile(int fd)
296	{
297	close(fd);
298	}
299
300
301	/*++++++++++++++++++++++++++++++++++++++
302	Delete a file from disk.
303
304	int DeleteFile Returns 0 if OK or something else in case of an error.
305
306	char *filename The name of the file to delete.
307	++++++++++++++++++++++++++++++++++++++*/
308
309	int DeleteFile(char *filename)
310	{
311	unlink(filename);
312
313	return(0);
314	}