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xmount_fuse.c
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xmount_fuse.c
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/*******************************************************************************
* xmount Copyright (c) 2008-2016 by Gillen Daniel <gillen.dan@pinguin.lu> *
* *
* 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 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 General Public License for *
* more details. *
* *
* You should have received a copy of the GNU General Public License along with *
* this program. If not, see <http://www.gnu.org/licenses/>. *
*******************************************************************************/
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <sys/types.h>
#include "xmount_fuse.h"
#include "xmount.h"
#define LOG_WARNING(...) { \
LIBXMOUNT_LOG_WARNING(__VA_ARGS__); \
}
#define LOG_ERROR(...) { \
LIBXMOUNT_LOG_ERROR(__VA_ARGS__); \
}
#define LOG_DEBUG(...) { \
LIBXMOUNT_LOG_DEBUG(glob_xmount.debug,__VA_ARGS__); \
}
/*******************************************************************************
* FUSE function implementation
******************************************************************************/
//! FUSE access implementation
/*!
* \param p_path Path of file to get attributes from
* \param perm Requested permissisons
* \return 0 on success, negated error code on error
*/
/*
int Xmount_FuseAccess(const char *path, int perm) {
// TODO: Implement propper file permission handling
// http://www.cs.cf.ac.uk/Dave/C/node20.html
// Values for the second argument to access.
// These may be OR'd together.
//#define R_OK 4 // Test for read permission.
//#define W_OK 2 // Test for write permission.
//#define X_OK 1 // Test for execute permission.
//#define F_OK 0 // Test for existence.
return 0;
}
*/
//! FUSE getattr implementation
/*!
* \param p_path Path of file to get attributes from
* \param p_stat Pointer to stat structure to save attributes to
* \return 0 on success, negated error code on error
*/
int Xmount_FuseGetAttr(const char *p_path, struct stat *p_stat) {
te_XmountError xmount_ret=e_XmountError_None;
memset(p_stat,0,sizeof(struct stat));
if((xmount_ret=Xmount_GetFileAttr(p_path,p_stat))!=e_XmountError_None) {
LOG_ERROR("Couldn't get file attributes: Error code %u!\n",xmount_ret);
return -ENOENT;
}
/*
if(strcmp(p_path,"/")==0) {
// Attributes of mountpoint
p_stat->st_mode=S_IFDIR | 0777;
p_stat->st_nlink=2;
} else if(strcmp(p_path,glob_xmount.output.p_virtual_image_path)==0) {
// Attributes of virtual image
if(!glob_xmount.output.writable) p_stat->st_mode=S_IFREG | 0444;
else p_stat->st_mode=S_IFREG | 0666;
p_stat->st_nlink=1;
// Get output image file size
if(!GetOutputImageSize((uint64_t*)&(p_stat->st_size))) {
LOG_ERROR("Couldn't get image size!\n");
return -ENOENT;
}
// Make sure virtual image seems to be fully allocated (not sparse file).
p_stat->st_blocks=p_stat->st_size/512;
if(p_stat->st_size%512!=0) p_stat->st_blocks++;
} else if(strcmp(p_path,glob_xmount.output.p_info_path)==0) {
// Attributes of virtual image info file
p_stat->st_mode=S_IFREG | 0444;
p_stat->st_nlink=1;
// Get virtual image info file size
if(glob_xmount.output.p_info_file!=NULL) {
p_stat->st_size=strlen(glob_xmount.output.p_info_file);
} else p_stat->st_size=0;
} else return -ENOENT;
// Set uid and gid of all files to uid and gid of current process
p_stat->st_uid=getuid();
p_stat->st_gid=getgid();
*/
return 0;
}
//! FUSE mkdir implementation
/*!
* \param p_path Directory path
* \param mode Directory permissions
* \return 0 on success, negated error code on error
*/
int Xmount_FuseMkDir(const char *p_path, mode_t mode) {
// TODO: Implement
LOG_ERROR("Attempt to create directory \"%s\" "
"on read-only filesystem!\n",p_path)
return -1;
}
//! FUSE create implementation.
/*!
* \param p_path File to create
* \param mode File mode
* \param dev ??? but not used
* \return 0 on success, negated error code on error
*/
int Xmount_FuseMkNod(const char *p_path, mode_t mode, dev_t dev) {
// TODO: Implement
LOG_ERROR("Attempt to create illegal file \"%s\"\n",p_path)
return -1;
}
//! FUSE readdir implementation
/*!
* \param p_path Path from where files should be listed
* \param p_buf Buffer to write file entrys to
* \param filler Function to write dir entrys to buffer
* \param offset ??? but not used
* \param p_fi File info struct
* \return 0 on success, negated error code on error
*/
int Xmount_FuseReadDir(const char *p_path,
void *p_buf,
fuse_fill_dir_t filler,
off_t offset,
struct fuse_file_info *p_fi)
{
uint64_t dir_entries=0;
char **pp_dir_entries=NULL;
te_XmountError xmount_ret=e_XmountError_None;
// Ignore some params
(void)offset;
(void)p_fi;
// Get directory listing
xmount_ret=Xmount_GetDirListing(p_path,
&dir_entries,
&pp_dir_entries);
if(xmount_ret!=e_XmountError_None) {
LOG_ERROR("Couldn't get directory listing: Error code %u!\n",xmount_ret);
return -ENOENT;
}
// Add std . and .. entrys
filler(p_buf,".",NULL,0);
filler(p_buf,"..",NULL,0);
// Add retrieved entries
for(uint64_t i=0;i<dir_entries;i++) {
filler(p_buf,pp_dir_entries[i],NULL,0);
XMOUNT_FREE(pp_dir_entries[i]);
}
XMOUNT_FREE(pp_dir_entries);
return 0;
}
//! FUSE open implementation
/*!
* \param p_path Path to file to open
* \param p_fi File info struct
* \return 0 on success, negated error code on error
*/
int Xmount_FuseOpen(const char *p_path, struct fuse_file_info *p_fi) {
#define CHECK_OPEN_PERMS() { \
if(!glob_xmount.output.writable && (p_fi->flags & 3)!=O_RDONLY) { \
LOG_DEBUG("Attempt to open the read-only file \"%s\" for writing.\n", \
p_path) \
return -EACCES; \
} \
return 0; \
}
if(strcmp(p_path,glob_xmount.output.p_virtual_image_path)==0 ||
strcmp(p_path,glob_xmount.output.p_info_path)==0)
{
CHECK_OPEN_PERMS();
}
#undef CHECK_OPEN_PERMS
LOG_DEBUG("Attempt to open inexistant file \"%s\".\n",p_path);
return -ENOENT;
}
//! FUSE read implementation
/*!
* \param p_path Path (relative to mount folder) of file to read data from
* \param p_buf Pre-allocated buffer where read data should be written to
* \param size Number of bytes to read
* \param offset Offset to start reading at
* \param p_fi: File info struct
* \return Read bytes on success, negated error code on error
*/
int Xmount_FuseRead(const char *p_path,
char *p_buf,
size_t size,
off_t offset,
struct fuse_file_info *p_fi)
{
(void)p_fi;
int ret;
uint64_t len;
#define READ_MEM_FILE(filebuf,filesize,filetypestr,mutex) { \
len=filesize; \
if(offset<len) { \
if(offset+size>len) { \
LOG_DEBUG("Attempt to read past EOF of virtual " filetypestr " file\n"); \
LOG_DEBUG("Adjusting read size from %u to %u\n",size,len-offset); \
size=len-offset; \
} \
pthread_mutex_lock(&mutex); \
memcpy(p_buf,filebuf+offset,size); \
pthread_mutex_unlock(&mutex); \
LOG_DEBUG("Read %" PRIu64 " bytes at offset %" PRIu64 \
" from virtual " filetypestr " file\n",size,offset); \
ret=size; \
} else { \
LOG_DEBUG("Attempt to read behind EOF of virtual " filetypestr " file\n"); \
ret=0; \
} \
}
if(strcmp(p_path,glob_xmount.output.p_virtual_image_path)==0) {
// Read data from virtual output file
// Wait for other threads to end reading/writing data
pthread_mutex_lock(&(glob_xmount.mutex_image_rw));
// Get requested data
if((ret=ReadOutputImageData(p_buf,offset,size))<0) {
LOG_ERROR("Couldn't read data from virtual image file!\n")
}
// Allow other threads to read/write data again
pthread_mutex_unlock(&(glob_xmount.mutex_image_rw));
} else if(strcmp(p_path,glob_xmount.output.p_info_path)==0) {
// Read data from virtual info file
READ_MEM_FILE(glob_xmount.output.p_info_file,
strlen(glob_xmount.output.p_info_file),
"info",
glob_xmount.mutex_info_read);
} else {
// Attempt to read non existant file
LOG_DEBUG("Attempt to read from non existant file \"%s\"\n",p_path)
ret=-ENOENT;
}
#undef READ_MEM_FILE
// TODO: Return size of read data!!!!!
return ret;
}
//! FUSE rename implementation
/*!
* \param p_path File to rename
* \param p_npath New filename
* \return 0 on error, negated error code on error
*/
int Xmount_FuseRename(const char *p_path, const char *p_npath) {
// TODO: Implement
return -ENOENT;
}
//! FUSE rmdir implementation
/*!
* \param p_path Directory to delete
* \return 0 on success, negated error code on error
*/
int Xmount_FuseRmDir(const char *p_path) {
// TODO: Implement
return -1;
}
//! FUSE unlink implementation
/*!
* \param p_path File to delete
* \return 0 on success, negated error code on error
*/
int Xmount_FuseUnlink(const char *p_path) {
// TODO: Implement
return -1;
}
//! FUSE statfs implementation
/*!
* \param p_path Get stats for fs that the specified file resides in
* \param stats Stats
* \return 0 on success, negated error code on error
*/
/*
int Xmount_FuseStatFs(const char *p_path, struct statvfs *stats) {
struct statvfs CacheFileFsStats;
int ret;
if(glob_xmount.writable==TRUE) {
// If write support is enabled, return stats of fs upon which cache file
// resides in
if((ret=statvfs(glob_xmount.p_cache_file,&CacheFileFsStats))==0) {
memcpy(stats,&CacheFileFsStats,sizeof(struct statvfs));
return 0;
} else {
LOG_ERROR("Couldn't get stats for fs upon which resides \"%s\"\n",
glob_xmount.p_cache_file)
return ret;
}
} else {
// TODO: Return read only
return 0;
}
}
*/
// FUSE write implementation
/*!
* \param p_buf Buffer containing data to write
* \param size Number of bytes to write
* \param offset Offset to start writing at
* \param p_fi: File info struct
*
* Returns:
* Written bytes on success, negated error code on error
*/
int Xmount_FuseWrite(const char *p_path,
const char *p_buf,
size_t size,
off_t offset,
struct fuse_file_info *p_fi)
{
(void)p_fi;
uint64_t len;
if(strcmp(p_path,glob_xmount.output.p_virtual_image_path)==0) {
// Wait for other threads to end reading/writing data
pthread_mutex_lock(&(glob_xmount.mutex_image_rw));
// Get output image file size
if(!GetOutputImageSize(&len)) {
LOG_ERROR("Couldn't get virtual image size!\n")
pthread_mutex_unlock(&(glob_xmount.mutex_image_rw));
return 0;
}
if(offset<len) {
if(offset+size>len) size=len-offset;
if(WriteOutputImageData(p_buf,offset,size)!=size) {
LOG_ERROR("Couldn't write data to virtual image file!\n")
pthread_mutex_unlock(&(glob_xmount.mutex_image_rw));
return 0;
}
} else {
LOG_DEBUG("Attempt to write past EOF of virtual image file\n")
pthread_mutex_unlock(&(glob_xmount.mutex_image_rw));
return 0;
}
// Allow other threads to read/write data again
pthread_mutex_unlock(&(glob_xmount.mutex_image_rw));
} else if(strcmp(p_path,glob_xmount.output.p_info_path)==0) {
// Attempt to write data to read only image info file
LOG_DEBUG("Attempt to write data to virtual info file\n");
return -ENOENT;
} else {
// Attempt to write to non existant file
LOG_DEBUG("Attempt to write to the non existant file \"%s\"\n",p_path)
return -ENOENT;
}
return size;
}

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