trunk/src/files.c

/***************************************
 Functions to handle files.

 Part of the Routino routing software.
 ******************/ /******************
 This file Copyright 2008-2013 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 <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/types.h>

#include "files.h"


/*+ A structure to contain the list of memory mapped files. +*/
struct mmapinfo
{
 const char  *filename;         /*+ The name of the file (the index of the list). +*/
       int    fd;               /*+ The file descriptor used when it was opened. +*/
       void  *address;          /*+ The address the file was mapped to. +*/
       size_t length;           /*+ The length of the file. +*/
};

/*+ The list of memory mapped files. +*/
static struct mmapinfo *mappedfiles;

/*+ The number of mapped files. +*/
static int nmappedfiles=0;


#define BUFFLEN 1024

/*+ A structure to contain the list of file buffers. +*/
struct filebuffer
{
 int    fd;                     /*+ The file descriptor used when it was opened. +*/
 char   buffer[BUFFLEN];        /*+ The data buffer. +*/
 size_t pointer;                /*+ The read/write pointer for the file buffer. +*/
 size_t length;                 /*+ The read pointer for the file buffer. +*/
 int    reading;                /*+ A flag to indicate if the file is for reading. +*/
};

/*+ The list of file buffers. +*/
static struct filebuffer **filebuffers=NULL;

/*+ The number of allocated file buffer pointers. +*/
static int nfilebuffers=0;


/* Local functions */

static void CreateFileBuffer(int fd,int read_write);


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

  char *FileName Returns a pointer to memory allocated to the filename.

  const char *dirname The directory name.

  const char *prefix The file prefix.

  const char *name The main part of the name.
  ++++++++++++++++++++++++++++++++++++++*/

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)+1);

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

 return(filename);
}


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

  void *MapFile Returns the address of the file or exits in case of an error.

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

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

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 /* Get its size */

 if(stat(filename,&buf))
   {
    fprintf(stderr,"Cannot stat file '%s' [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 size=buf.st_size;

 /* Map the file */

 address=mmap(NULL,size,PROT_READ,MAP_SHARED,fd,0);

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

    fprintf(stderr,"Cannot mmap file '%s' for reading [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 /* Store the information about the mapped file */

 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=size;

 nmappedfiles++;

 return(address);
}


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

  void *MapFileWriteable Returns the address of the file or exits in case of an error.

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

void *MapFileWriteable(const char *filename)
{
 int fd;
 struct stat buf;
 off_t size;
 void *address;

 /* Open the file */

 fd=open(filename,O_RDWR);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading and writing [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 /* Get its size */

 if(stat(filename,&buf))
   {
    fprintf(stderr,"Cannot stat file '%s' [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 size=buf.st_size;

 /* Map the file */

 address=mmap(NULL,size,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);

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

    fprintf(stderr,"Cannot mmap file '%s' for reading and writing [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 /* Store the information about the mapped file */

 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=size;

 nmappedfiles++;

 return(address);
}


/*++++++++++++++++++++++++++++++++++++++
  Unmap a file and close it.

  void *UnmapFile Returns NULL (for similarity to the MapFile function).

  const void *address The address of the mapped file in memory.
  ++++++++++++++++++++++++++++++++++++++*/

void *UnmapFile(const void *address)
{
 int i;

 for(i=0;i<nmappedfiles;i++)
    if(mappedfiles[i].address==address)
       break;

 if(i==nmappedfiles)
   {
    fprintf(stderr,"The data at address %p was not mapped using MapFile().\n",address);
    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 an existing file on disk for reading.

  int SlimMapFile Returns the file descriptor if OK or exits in case of an error.

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

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

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 CreateFileBuffer(fd,0);

 return(fd);
}


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

  int SlimMapFileWriteable Returns the file descriptor if OK or exits in case of an error.

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

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

 /* Open the file */

 fd=open(filename,O_RDWR);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading and writing [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 CreateFileBuffer(fd,0);

 return(fd);
}


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

  int SlimUnmapFile returns -1 (for similarity to the UnmapFile function).

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

int SlimUnmapFile(int fd)
{
 close(fd);

 return(-1);
}


/*++++++++++++++++++++++++++++++++++++++
  Open a new file on disk for writing (with buffering).

  int OpenFileBufferedNew Returns the file descriptor if OK or exits in case of an error.

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

int OpenFileBufferedNew(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' for writing [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 CreateFileBuffer(fd,-1);

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Open a new or existing file on disk for appending (with buffering).

  int OpenFileBufferedAppend Returns the file descriptor if OK or exits in case of an error.

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

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

 /* Open the file */

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

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for appending [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 CreateFileBuffer(fd,-1);

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Open an existing file on disk for reading (with buffering).

  int ReOpenFileBuffered Returns the file descriptor if OK or exits in case of an error.

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

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

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 CreateFileBuffer(fd,1);

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Write data to a file descriptor (via a buffer).

  int WriteFileBuffered 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.

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

int WriteFileBuffered(int fd,const void *address,size_t length)
{
 logassert(fd!=-1,"File descriptor is in error - report a bug");

 logassert(fd<nfilebuffers && filebuffers[fd],"File descriptor has no buffer - report a bug");

 logassert(!filebuffers[fd]->reading,"File descriptor was not opened for writing - report a bug");

 /* Write the data */

 if((filebuffers[fd]->pointer+length)>BUFFLEN)
   {
    if(write(fd,filebuffers[fd]->buffer,filebuffers[fd]->pointer)!=(ssize_t)filebuffers[fd]->pointer)
       return(-1);

    filebuffers[fd]->pointer=0;
   }

 if(length>=BUFFLEN)
   {
    if(write(fd,address,length)!=(ssize_t)length)
       return(-1);

    return(0);
   }

 memcpy(filebuffers[fd]->buffer+filebuffers[fd]->pointer,address,length);

 filebuffers[fd]->pointer+=length;

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Read data from a file descriptor (via a buffer).

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

  int fd The file descriptor to read from.

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

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

int ReadFileBuffered(int fd,void *address,size_t length)
{
 logassert(fd!=-1,"File descriptor is in error - report a bug");

 logassert(fd<nfilebuffers && filebuffers[fd],"File descriptor has no buffer - report a bug");

 logassert(filebuffers[fd]->reading,"File descriptor was not opened for reading - report a bug");

 /* Read the data */

 if((filebuffers[fd]->pointer+length)>filebuffers[fd]->length)
    if(filebuffers[fd]->pointer<filebuffers[fd]->length)
      {
       memcpy(address,filebuffers[fd]->buffer+filebuffers[fd]->pointer,filebuffers[fd]->length-filebuffers[fd]->pointer);

       address+=filebuffers[fd]->length-filebuffers[fd]->pointer;
       length-=filebuffers[fd]->length-filebuffers[fd]->pointer;

       filebuffers[fd]->pointer=0;
       filebuffers[fd]->length=0;
      }

 if(length>=BUFFLEN)
   {
    if(read(fd,address,length)!=(ssize_t)length)
       return(-1);

    return(0);
   }

 if(filebuffers[fd]->pointer==filebuffers[fd]->length)
   {
    ssize_t len=read(fd,filebuffers[fd]->buffer,BUFFLEN);

    if(len<=0)
       return(-1);


    filebuffers[fd]->length=len;
    filebuffers[fd]->pointer=0;
   }

 if(filebuffers[fd]->length==0)
    return(-1);

 memcpy(address,filebuffers[fd]->buffer+filebuffers[fd]->pointer,length);

 filebuffers[fd]->pointer+=length;

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Seek to a position in a file descriptor that uses a buffer.

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

  int fd The file descriptor to seek within.

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

int SeekFileBuffered(int fd,off_t position)
{
 logassert(fd!=-1,"File descriptor is in error - report a bug");

 logassert(fd<nfilebuffers && filebuffers[fd],"File descriptor has no buffer - report a bug");

 /* Seek the data - doesn't need to be highly optimised */

 if(!filebuffers[fd]->reading)
    if(write(fd,filebuffers[fd]->buffer,filebuffers[fd]->pointer)!=(ssize_t)filebuffers[fd]->pointer)
       return(-1);

 filebuffers[fd]->pointer=0;
 filebuffers[fd]->length=0;

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

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Skip forward by an offset in a file descriptor that uses a buffer.

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

  int fd The file descriptor to skip within.

  off_t skip The amount to skip forward.
  ++++++++++++++++++++++++++++++++++++++*/

int SkipFileBuffered(int fd,off_t skip)
{
 logassert(fd!=-1,"File descriptor is in error - report a bug");

 logassert(fd<nfilebuffers && filebuffers[fd],"File descriptor has no buffer - report a bug");

 logassert(filebuffers[fd]->reading,"File descriptor was not opened for reading - report a bug");

 /* Skip the data - needs to be optimised */

 if((filebuffers[fd]->pointer+skip)>filebuffers[fd]->length)
   {
    skip-=filebuffers[fd]->length-filebuffers[fd]->pointer;

    filebuffers[fd]->pointer=0;
    filebuffers[fd]->length=0;

    if(lseek(fd,skip,SEEK_CUR)==-1)
       return(-1);
   }
 else
    filebuffers[fd]->pointer+=skip;

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Get the size of a file.

  off_t SizeFile Returns the file size if OK or exits in case of an error.

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

off_t SizeFile(const char *filename)
{
 struct stat buf;

 if(stat(filename,&buf))
   {
    fprintf(stderr,"Cannot stat file '%s' [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 return(buf.st_size);
}


/*++++++++++++++++++++++++++++++++++++++
  Check if a file exists.

  int ExistsFile Returns 1 if the file exists and 0 if not.

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

int ExistsFile(const char *filename)
{
 struct stat buf;

 if(stat(filename,&buf))
    return(0);
 else
    return(1);
}


/*++++++++++++++++++++++++++++++++++++++
  Close a file on disk (and flush the buffer).

  int CloseFileBuffered returns -1 (for similarity to the *OpenFileBuffered* functions).

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

int CloseFileBuffered(int fd)
{
 logassert(fd<nfilebuffers && filebuffers[fd],"File descriptor has no buffer - report a bug");

 if(!filebuffers[fd]->reading)
    write(fd,filebuffers[fd]->buffer,filebuffers[fd]->pointer);

 close(fd);

 free(filebuffers[fd]);

 filebuffers[fd]=NULL;

 return(-1);
}


/*++++++++++++++++++++++++++++++++++++++
  Open an existing file on disk for reading (in a simple mode).

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

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

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

 /* Open the file */

 fd=open(filename,O_RDONLY);

 if(fd<0)
   {
    fprintf(stderr,"Cannot open file '%s' for reading [%s].\n",filename,strerror(errno));
    exit(EXIT_FAILURE);
   }

 return(fd);
}


/*++++++++++++++++++++++++++++++++++++++
  Close a file on disk (that was opened in simple mode).

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

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


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

  int DeleteFile Returns 0 if OK.

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

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

 return(0);
}


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

  int RenameFile Returns 0 if OK.

  const char *oldfilename The old name of the file before renaming.

  const char *newfilename The new name of the file after renaming.
  ++++++++++++++++++++++++++++++++++++++*/

int RenameFile(const char *oldfilename,const char *newfilename)
{
 rename(oldfilename,newfilename);

 return(0);
}


/*++++++++++++++++++++++++++++++++++++++
  Create a file buffer.

  int fd The file descriptor.

  int read_write A flag set to 1 for reading, -1 for writing and 0 for unbuffered.
  ++++++++++++++++++++++++++++++++++++++*/

static void CreateFileBuffer(int fd,int read_write)
{
 if(nfilebuffers<=fd)
   {
    int i;

    filebuffers=(struct filebuffer**)realloc((void*)filebuffers,(fd+1)*sizeof(struct filebuffer*));

    for(i=nfilebuffers;i<=fd;i++)
       filebuffers[i]=NULL;

    nfilebuffers=fd+1;
   }

 if(read_write)
   {
    filebuffers[fd]=(struct filebuffer*)calloc(sizeof(struct filebuffer),1);

    filebuffers[fd]->reading=(read_write==1);
   }
}