/**************************************************************************** * fs_fat32.c * * Copyright (C) 2007 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name Gregory Nutt nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include "fs_internal.h" #include "fs_fat32.h" #if CONFIG_FS_FAT /**************************************************************************** * Definitions ****************************************************************************/ /* Access to data in raw sector data */ #define UBYTE_VAL(p,o) (((ubyte*)(p))[o]) #define UBYTE_PTR(p,o) &UBYTE_VAL(p,o) #define UBYTE_PUT(p,o,v) (UBYTE_VAL(p,o)=(ubyte)(v)) #define UINT16_PTR(p,o) ((uint16*)UBYTE_PTR(p,o)) #define UINT16_VAL(p,o) (*UINT16_PTR(p,o)) #define UINT16_PUT(p,o,v) (UINT16_VAL(p,o)=(uint16)(v)) #define UINT32_PTR(p,o) ((uint32*)UBYTE_PTR(p,o)) #define UINT32_VAL(p,o) (*UINT32_PTR(p,o)) #define UINT32_PUT(p,o,v) (UINT32_VAL(p,o)=(uint32)(v)) /* Regardless of the endian-ness of the target or alignment of the data, no * special operations are required for byte, string or byte array accesses. * The FAT data stream is little endian so multiple byte values must be * accessed byte-by-byte for big-endian targets. */ #define MBR_GETSECPERCLUS(p) UBYTE_VAL(p,BS_SECPERCLUS) #define MBR_GETNUMFATS(p) UBYTE_VAL(p,BS_NUMFATS) #define MBR_GETMEDIA(p) UBYTE_VAL(p,BS_MEDIA) #define MBR_GETDRVNUM(p) UBYTE_VAL(p,BS32_DRVNUM) #define MBR_GETBOOTSIG(p) UBYTE_VAL(p,BS32_BOOTSIG) #define MBR_PUTSECPERCLUS(p,v) UBYTE_PUT(p,BS_SECPERCLUS),v) #define MBR_PUTNUMFATS(p,v) UBYTE_PUT(p,BS_NUMFATS,v) #define MBR_PUTMEDIA(p,v) UBYTE_PUT(p,BS_MEDIA,v) #define MBR_PUTDRVNUM(p,v) UBYTE_PUT(p,BS32_DRVNUM,v) #define MBR_PUTBOOTSIG(p,v) UBYTE_PUT(p,BS32_BOOTSIG,v) /* For the all targets, unaligned values need to be accessed byte-by-byte. * Some architectures may handle unaligned accesses with special interrupt * handlers. But even in that case, it is more efficient to avoid the traps. */ /* Unaligned multi-byte access macros */ #define MBR_GETBYTESPERSEC(p) fat_getuint16(UBYTE_PTR(p,BS_BYTESPERSEC)) #define MBR_GETROOTENTCNT(p) fat_getuint16(UBYTE_PTR(p,BS_ROOTENTCNT)) #define MBR_GETTOTSEC16(p) fat_getuint16(UBYTE_PTR(p,BS_TOTSEC16)) #define MBR_GETVOLID(p) fat_getuint32(UBYTE_PTR(p,BS32_VOLID)) #define MBR_PUTBYTESPERSEC(p,v) fat_putuint16(UBYTE_PTR(p,BS_BYTESPERSEC),v) #define MBR_PUTROOTENTCNT(p,v) fat_putuint16(UBYTE_PTR(p,BS_ROOTENTCNT),v) #define MBR_PUTTOTSEC16(p,v) fat_putuint16(UBYTE_PTR(p,BS_TOTSEC16),v) #define MBR_PUTVOLID(p,v) fat_putuint32(UBYTE_PTR(p,BS32_VOLID),v) /* But for multi-byte values, the endian-ness of the target vs. the little * endian order of the byte stream or alignment of the data within the byte * stream can force special, byte-by-byte accesses. */ #ifdef CONFIG_ARCH_BIGENDIAN /* If the target is big-endian, then even aligned multi-byte values must be * accessed byte-by-byte. */ # define MBR_GETRESVDSECCOUNT(p) fat_getuint16(UBYTE_PTR(p,BS_RESVDSECCOUNT)) # define MBR_GETFATSZ16(p) fat_getuint16(UBYTE_PTR(p,BS_FATSZ16)) # define MBR_GETSECPERTRK(p) fat_getuint16(UBYTE_PTR(p,BS_SECPERTRK)) # define MBR_GETNUMHEADS(p) fat_getuint16(UBYTE_PTR(p,BS_NUMHEADS)) # define MBR_GETHIDSEC(p) fat_getuint32(UBYTE_PTR(p,BS_HIDSEC)) # define MBR_GETTOTSEC32(p) fat_getuint32(UBYTE_PTR(p,BS_TOTSEC32)) # define MBR_GETFATSZ32(p) fat_getuint32(UBYTE_PTR(p,BS32_FATSZ32)) # define MBR_GETEXTFLAGS(p) fat_getuint16(UBYTE_PTR(p,BS32_EXTFLAGS)) # define MBR_GETFSVER(p) fat_getuint16(UBYTE_PTR(p,BS32_FSVER)) # define MBR_GETROOTCLUS(p) fat_getuint32(UBYTE_PTR(p,BS32_ROOTCLUS)) # define MBR_GETFSINFO(p) fat_getuint16(UBYTE_PTR(p,BS32_FSINFO)) # define MBR_GETBKBOOTSEC(p) fat_getuint16(UBYTE_PTR(p,BS32_BKBOOTSEC)) # define MBR_GETSIGNATURE(p) fat_getuint16(UBYTE_PTR(p,BS_SIGNATURE)) # define MBR_GETPARTSECTOR(s) fat_getuint32(s); # define FSI_GETLEADSIG(p) fat_getuint32(UBYTE_PTR(p,FSI_LEADSIG)) # define FSI_GETSTRUCTSIG(p) fat_getuint32(UBYTE_PTR(p,FSI_STRUCTSIG)) # define FSI_GETFREECOUNT(p) fat_getuint32(UBYTE_PTR(p,FSI_FREECOUNT)) # define FSI_GETNXTFREE(p) fat_getuint32(UBYTE_PTR(p,FSI_NXTFREE)) # define FSI_GETTRAILSIG(p) fat_getuint32(UBYTE_PTR(p,FSI_TRAILSIG)) # define MBR_PUTRESVDSECCOUNT(p,v) fat_putuint16(UBYTE_PTR(p,BS_RESVDSECCOUNT,v)) # define MBR_PUTFATSZ16(p,v) fat_putuint16(UBYTE_PTR(p,BS_FATSZ16,v)) # define MBR_PUTSECPERTRK(p,v) fat_putuint16(UBYTE_PTR(p,BS_SECPERTRK,v)) # define MBR_PUTNUMHEADS(p,v) fat_putuint16(UBYTE_PTR(p,BS_NUMHEADS,v)) # define MBR_PUTHIDSEC(p,v) fat_putuint32(UBYTE_PTR(p,BS_HIDSEC,v)) # define MBR_PUTTOTSEC32(p,v) fat_putuint32(UBYTE_PTR(p,BS_TOTSEC32,v)) # define MBR_PUTFATSZ32(p,v) fat_putuint32(UBYTE_PTR(p,BS32_FATSZ32,v)) # define MBR_PUTEXTFLAGS(p,v) fat_putuint16(UBYTE_PTR(p,BS32_EXTFLAGS,v)) # define MBR_PUTFSVER(p,v) fat_putuint16(UBYTE_PTR(p,BS32_FSVER,v)) # define MBR_PUTROOTCLUS(p,v) fat_putuint32(UBYTE_PTR(p,BS32_ROOTCLUS,v)) # define MBR_PUTFSINFO(p,v) fat_putuint16(UBYTE_PTR(p,BS32_FSINFO,v)) # define MBR_PUTBKBOOTSEC(p,v) fat_putuint16(UBYTE_PTR(p,BS32_BKBOOTSEC,v)) # define MBR_PUTSIGNATURE(p,v) fat_getuint16(UBYTE_PTR(p,BS_SIGNATURE),v) # define FSI_PUTLEADSIG(p,v) fat_putuint32(UBYTE_PTR(p,FSI_LEADSIG),v) # define FSI_PUTSTRUCTSIG(p,v) fat_putuint32(UBYTE_PTR(p,FSI_STRUCTSIG),v) # define FSI_PUTFREECOUNT(p,v) fat_putuint32(UBYTE_PTR(p,FSI_FREECOUNT),v) # define FSI_PUTNXTFREE(p,v) fat_putuint32(UBYTE_PTR(p,FSI_NXTFREE),v) # define FSI_PUTTRAILSIG(p,v) fat_putuint32(UBYTE_PTR(p,FSI_TRAILSIG),v) #else /* But nothing special has to be done for the little endian-case for access * to aligned mulitbyte values. */ # define MBR_GETRESVDSECCOUNT(p) UINT16_VAL(p,BS_RESVDSECCOUNT) # define MBR_GETFATSZ16(p) UINT16_VAL(p,BS_FATSZ16) # define MBR_GETSECPERTRK(p) UINT16_VAL(p,BS_SECPERTRK) # define MBR_GETNUMHEADS(p) UINT16_VAL(p,BS_NUMHEADS) # define MBR_GETHIDSEC(p) UINT32_VAL(p,BS_HIDSEC) # define MBR_GETTOTSEC32(p) UINT32_VAL(p,BS_TOTSEC32) # define MBR_GETFATSZ32(p) UINT32_VAL(p,BS32_FATSZ32) # define MBR_GETEXTFLAGS(p) UINT16_VAL(p,BS32_EXTFLAGS) # define MBR_GETFSVER(p) UINT16_VAL(p,BS32_FSVER) # define MBR_GETROOTCLUS(p) UINT32_VAL(p,BS32_ROOTCLUS) # define MBR_GETFSINFO(p) UINT16_VAL(p,BS32_FSINFO) # define MBR_GETBKBOOTSEC(p) UINT16_VAL(p,BS32_BKBOOTSEC) # define MBR_GETSIGNATURE(p) UINT16_VAL(p,BS_SIGNATURE) # define MBR_GETPARTSECTOR(s) (*((uint32*)(s))) # define FSI_GETLEADSIG(p) UINT32_VAL(p,FSI_LEADSIG) # define FSI_GETSTRUCTSIG(p) UINT32_VAL(p,FSI_STRUCTSIG) # define FSI_GETFREECOUNT(p) UINT32_VAL(p,FSI_FREECOUNT) # define FSI_GETNXTFREE(p) UINT32_VAL(p,FSI_NXTFREE) # define FSI_GETTRAILSIG(p) UINT32_VAL(p,FSI_TRAILSIG) # define MBR_PUTRESVDSECCOUNT(p,v) UINT16_PUT(p,BS_RESVDSECCOUNT,v) # define MBR_PUTFATSZ16(p,v) UINT16_PUT(p,BS_FATSZ16,v) # define MBR_PUTSECPERTRK(p,v) UINT16_PUT(p,BS_SECPERTRK,v) # define MBR_PUTNUMHEADS(p,v) UINT16_PUT(p,BS_NUMHEADS,v) # define MBR_PUTHIDSEC(p,v) UINT32_PUT(p,BS_HIDSEC,v) # define MBR_PUTTOTSEC32(p,v) UINT32_PUT(p,BS_TOTSEC32,v) # define MBR_PUTFATSZ32(p,v) UINT32_PUT(p,BS32_FATSZ32,v) # define MBR_PUTEXTFLAGS(p,v) UINT16_PUT(p,BS32_EXTFLAGS,v) # define MBR_PUTFSVER(p,v) UINT16_PUT(p,BS32_FSVER,v) # define MBR_PUTROOTCLUS(p,v) UINT32_PUT(p,BS32_ROOTCLUS,v) # define MBR_PUTFSINFO(p,v) UINT16_PUT(p,BS32_FSINFO,v) # define MBR_PUTBKBOOTSEC(p,v) UINT16_PUT(p,BS32_BKBOOTSEC,v) # define MBR_PUTSIGNATURE(p,v) UINT16_PUT(p,BS_SIGNATURE,v) # define FSI_PUTLEADSIG(p) UINT32_PUT(p,FSI_LEADSIG) # define FSI_PUTSTRUCTSIG(p) UINT32_PUT(p,FSI_STRUCTSIG) # define FSI_PUTFREECOUNT(p) UINT32_PUT(p,FSI_FREECOUNT) # define FSI_PUTNXTFREE(p) UINT32_PUT(p,FSI_NXTFREE) # define FSI_PUTTRAILSIG(p) UINT32_PUT(p,FSI_TRAILSIG) #endif /**************************************************************************** * Private Types ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int fat_open(FAR struct file *filp, const char *rel_path, int oflags, mode_t mode); static int fat_close(FAR struct file *filp); static ssize_t fat_read(FAR struct file *filp, char *buffer, size_t buflen); static ssize_t fat_write(FAR struct file *filp, const char *buffer, size_t buflen); static off_t fat_seek(FAR struct file *filp, off_t offset, int whence); static int fat_ioctl(FAR struct file *filp, int cmd, unsigned long arg); static int fat_bind(FAR struct inode *blkdriver, const void *data, void **handle); static int fat_unbind(void *handle); /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Public Variables ****************************************************************************/ /* See fs_mount.c -- this structure is explicitly externed there. * We use the old-fashioned kind of initializers so that this will compile * with any compiler. */ const struct mountpt_operations fat_operations = { fat_open, fat_close, fat_read, fat_write, fat_seek, fat_ioctl, fat_bind, fat_unbind }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: fat_getuint16 ****************************************************************************/ static uint16 fat_getuint16(ubyte *ptr) { #ifdef CONFIG_ARCH_BIGENDIAN /* The bytes always have to be swapped if the target is big-endian */ return ((uint16)ptr[0] << 8) | ptr[1]; #else /* Byte-by-byte transfer is still necessary if the address is un-aligned */ return ((uint16)ptr[1] << 8) | ptr[0]; #endif } /**************************************************************************** * Name: fat_getuint32 ****************************************************************************/ static uint32 fat_getuint32(ubyte *ptr) { #ifdef CONFIG_ARCH_BIGENDIAN /* The bytes always have to be swapped if the target is big-endian */ return ((uint32)fat_getuint16(&ptr[0]) << 16) | fat_getuint16(&ptr[2]); #else /* Byte-by-byte transfer is still necessary if the address is un-aligned */ return ((uint32)fat_getuint16(&ptr[2]) << 16) | fat_getuint16(&ptr[0]); #endif } /**************************************************************************** * Name: fat_putuint16 ****************************************************************************/ static void fat_putuint16(ubyte *ptr, uint16 value16) { ubyte *val = (ubyte*)&value16; #ifdef CONFIG_ARCH_BIGENDIAN /* The bytes always have to be swapped if the target is big-endian */ ptr[0] = val[1]; ptr[1] = val[0]; #else /* Byte-by-byte transfer is still necessary if the address is un-aligned */ ptr[0] = val[0]; ptr[1] = val[1]; #endif } /**************************************************************************** * Name: fat_putuint32 ****************************************************************************/ static void fat_putuint32(ubyte *ptr, uint32 value32) { uint16 *val = (uint16*)&value32; #ifdef CONFIG_ARCH_BIGENDIAN /* The bytes always have to be swapped if the target is big-endian */ fat_putuint16(&ptr[0], val[2]); fat_putuint16(&ptr[2], val[0]); #else /* Byte-by-byte transfer is still necessary if the address is un-aligned */ fat_putuint16(&ptr[0], val[0]); fat_putuint16(&ptr[2], val[2]); #endif } /**************************************************************************** * Name: fat_semtake ****************************************************************************/ static void fat_semtake(struct fat_mountpt_s *fs) { /* Take the semaphore (perhaps waiting) */ while (sem_wait(&fs->fs_sem) != 0) { /* The only case that an error should occur here is if * the wait was awakened by a signal. */ ASSERT(*get_errno_ptr() == EINTR); } } /**************************************************************************** * Name: fat_semgive ****************************************************************************/ static inline void fat_semgive(struct fat_mountpt_s *fs) { sem_post(&fs->fs_sem); } /**************************************************************************** * Name: fat_checkmount * * Desciption: Check if the mountpoint is still valid. * * The caller should hold the mountpoint semaphore * ****************************************************************************/ static int fat_checkmount(struct fat_mountpt_s *fs) { /* If the fs_mounted flag is FALSE, then we have already handled the loss * of the mount. */ if (fs->fs_mounted) { struct fat_file_s *file; /* We still think the mount is healthy. Check an see if this is * still the case */ if (fs->fs_blkdriver) { struct inode *inode = fs->fs_blkdriver; if (inode && inode->u.i_bops && inode->u.i_bops->geometry) { struct geometry geo; int errcode = inode->u.i_bops->geometry(inode, &geo); if (errcode == OK && geo.geo_available && !geo.geo_mediachanged) { return OK; } } } /* If we get here, the mount is NOT healthy */ fs->fs_mounted = FALSE; /* Make sure that this is flagged in every opened file */ for (file = fs->fs_head; file; file = file->ff_next) { file->ff_open = FALSE; } } return -ENODEV; } /**************************************************************************** * Name: fat_bread * * Desciption: Read the specified sector * ****************************************************************************/ static int fat_bread(struct fat_mountpt_s *fs, size_t sector) { int ret = -ENODEV; if (fs && fs->fs_blkdriver ) { struct inode *inode = fs->fs_blkdriver; if (inode && inode->u.i_bops && inode->u.i_bops->read) { ssize_t nSectorsRead = inode->u.i_bops->read(inode, fs->fs_buffer, sector, 1); if (nSectorsRead == 1) { ret = OK; } else if (nSectorsRead < 0) { ret = nSectorsRead; } } } return ret; } /**************************************************************************** * Name: fat_readfsinfo * * Desciption: Read the FAT32 FSINFO sector * ****************************************************************************/ static int fat_readfsinfo(struct fat_mountpt_s *fs) { /* Verify that this is, indeed, an FSINFO sector */ if (FSI_GETLEADSIG(fs->fs_buffer) == 0x41615252 && FSI_GETSTRUCTSIG(fs->fs_buffer) == 0x61417272 && FSI_GETTRAILSIG(fs->fs_buffer) == 0xaa550000) { fs->fs_fsinextfree = FSI_GETFREECOUNT(fs->fs_buffer); fs->fs_fsifreecount = FSI_GETNXTFREE(fs->fs_buffer); return OK; } return -ENODEV; } /**************************************************************************** * Name: fat_checkbootrecord * * Desciption: Read a sector and verify that it is a a FAT boot record. * ****************************************************************************/ static int fat_checkbootrecord(struct fat_mountpt_s *fs) { uint32 ndatasectors; uint32 fatsize; /* Verify the MBR signature at offset 510 in the sector (true even * if the sector size is greater than 512. All FAT file systems have * this signature. On a FAT32 volume, the RootEntCount , FatSz16, and * FatSz32 values should always be zero. The FAT sector size should * match the reported hardware sector size. */ if (MBR_GETSIGNATURE(fs->fs_buffer) != 0xaa55 || MBR_GETROOTENTCNT(fs->fs_buffer) != 0 || MBR_GETBYTESPERSEC(fs->fs_buffer) != fs->fs_hwsectorsize) { return -ENODEV; } /* Verify the FAT32 file system type. The determination of the file * system type is based on the number of clusters on the volume: FAT12 * volume has < 4085 cluseter, a FAT16 volume has fewer than 65,525 * clusters, and any larger is FAT32. * * Determine the number of sectors in a FAT. */ fs->fs_fatsize = MBR_GETFATSZ16(fs->fs_buffer); /* Should be zero */ if (!fs->fs_fatsize) { fs->fs_fatsize = MBR_GETFATSZ32(fs->fs_buffer); } if (fs->fs_fatsize >= fs->fs_hwnsectors) { return -ENODEV; } /* Get the total number of sectors on the volume. */ fs->fs_fattotsec = MBR_GETTOTSEC16(fs->fs_buffer); /* Should be zero */ if (!fs->fs_fattotsec) { fs->fs_fattotsec = MBR_GETTOTSEC32(fs->fs_buffer); } if (fs->fs_fattotsec > fs->fs_hwnsectors) { return -ENODEV; } /* Get the total number of reserved sectors */ fs->fs_fatresvdseccount = MBR_GETRESVDSECCOUNT(fs->fs_buffer); if (fs->fs_fatresvdseccount > fs->fs_hwnsectors) { return -ENODEV; } /* Get the number of FATs. This is probably two but could have other values */ fs->fs_fatnumfats = MBR_GETNUMFATS(fs->fs_buffer); fatsize = fs->fs_fatnumfats * fs->fs_fatsize; /* Get the total number of data sectors */ ndatasectors = fs->fs_fattotsec - fs->fs_fatresvdseccount - fatsize; if (ndatasectors > fs->fs_hwnsectors) { return -ENODEV; } /* Get the sectors per cluster */ fs->fs_fatsecperclus = MBR_GETSECPERCLUS(fs->fs_buffer); /* Calculate the number of clusters */ fs->fs_nclusters = ndatasectors / fs->fs_fatsecperclus; /* Finally, the test: */ if (fs->fs_nclusters < 65525) { return -ENODEV; } /* We have what appears to be a valid FAT filesystem! Save a few more things * from the boot record that we will need later. */ fs->fs_fsinfo = fs->fs_fatbase + MBR_GETFSINFO(fs->fs_buffer); fs->fs_fatbase += fs->fs_fatresvdseccount; fs->fs_database = fs->fs_fatbase + fatsize; fs->fs_rootclus = MBR_GETROOTCLUS(fs->fs_buffer); fs->fs_fsifreecount = 0xffffffff; return OK; } /**************************************************************************** * Name: fat_mount * * Desciption: This function is called only when the mountpoint is first * established. It initializes the mountpoint structure and verifies * that a valid FAT32 filesystem is provided by the block driver. * * The caller should hold the mountpoint semaphore * ****************************************************************************/ static int fat_mount(struct fat_mountpt_s *fs, boolean writeable) { FAR struct inode *inode; struct geometry geo; int ret; /* Assume that the mount is successful */ fs->fs_mounted = TRUE; /* Check if there is media available */ inode = fs->fs_blkdriver; if (!inode || !inode->u.i_bops || !inode->u.i_bops->geometry || inode->u.i_bops->geometry(inode, &geo) != OK || !geo.geo_available) { ret = -ENODEV; goto errout; } /* Make sure that that the media is write-able (if write access is needed) */ if (writeable && !geo.geo_writeenabled) { ret = -EACCES; goto errout; } /* Save the hardware geometry */ fs->fs_hwsectorsize = geo.geo_sectorsize; fs->fs_hwnsectors = geo.geo_nsectors; /* Allocate a buffer to hold one hardware sector */ fs->fs_buffer = (ubyte*)malloc(fs->fs_hwsectorsize); if (!fs->fs_buffer) { ret = -ENOMEM; goto errout; } /* Search FAT boot record on the drive. First check at sector zero. This * could be either the boot record or a partition that refers to the boot * record. * * First read sector zero. This will be the first access to the drive and a * likely failure point. */ fs->fs_fatbase = 0; ret = fat_bread(fs, 0); if (ret < 0) { goto errout_with_buffer; } if (fat_checkbootrecord(fs) != OK) { /* The contents of sector 0 is not a boot record. It could be a * partition, however. Assume it is a partition and get the offset * into the partition table. This table is at offset MBR_TABLE and is * indexed by 16x the partition number. Here we support only * parition 0. */ ubyte *partition = &fs->fs_buffer[MBR_TABLE + 0]; /* Check if the partition exists and, if so, get the bootsector for that * partition and see if we can find the boot record there. */ if (partition[4]) { /* There appears to be a partition, get the sector number of the * partition (LBA) */ fs->fs_fatbase = MBR_GETPARTSECTOR(&partition[8]); /* Read the new candidate boot sector */ ret = fat_bread(fs, 0); if (ret < 0) { goto errout_with_buffer; } /* Check if this is a boot record */ if (fat_checkbootrecord(fs) != OK) { goto errout_with_buffer; } } } /* We have what appears to be a valid FAT filesystem! Now read the * FSINFO sector. */ ret = fat_readfsinfo(fs); if (ret != OK) { goto errout_with_buffer; } /* We did it! */ return OK; errout_with_buffer: free(fs->fs_buffer); fs->fs_buffer = 0; errout: fs->fs_mounted = FALSE; return ret; } /**************************************************************************** * Name: fat_open ****************************************************************************/ static int fat_open(FAR struct file *filp, const char *rel_path, int oflags, mode_t mode) { struct fat_mountpt_s *fs = filp->f_priv; int ret; /* Make sure that the mount is still healthy */ ret = fat_checkmount(fs); if (ret != OK) { return ret; } return -ENOSYS; } /**************************************************************************** * Name: fat_close ****************************************************************************/ static int fat_close(FAR struct file *filp) { struct fat_mountpt_s *fs = filp->f_priv; /* Do not check if the mount is healthy. We must support closing of * the file even when there is healthy mount. */ return -ENOSYS; } /**************************************************************************** * Name: fat_read ****************************************************************************/ static ssize_t fat_read(FAR struct file *filp, char *buffer, size_t buflen) { struct fat_mountpt_s *fs = filp->f_priv; int ret; /* Make sure that the mount is still healthy */ ret = fat_checkmount(fs); if (ret != OK) { return ret; } return -ENOSYS; } /**************************************************************************** * Name: fat_write ****************************************************************************/ static ssize_t fat_write(FAR struct file *filp, const char *buffer, size_t buflen) { struct fat_mountpt_s *fs = filp->f_priv; int ret; /* Make sure that the mount is still healthy */ ret = fat_checkmount(fs); if (ret != OK) { return ret; } return -ENOSYS; } /**************************************************************************** * Name: fat_seek ****************************************************************************/ static off_t fat_seek(FAR struct file *filp, off_t offset, int whence) { struct fat_mountpt_s *fs = filp->f_priv; int ret; /* Make sure that the mount is still healthy */ ret = fat_checkmount(fs); if (ret != OK) { return ret; } return -ENOSYS; } /**************************************************************************** * Name: fat_ioctl ****************************************************************************/ static int fat_ioctl(FAR struct file *filp, int cmd, unsigned long arg) { struct fat_mountpt_s *fs = filp->f_priv; int ret; /* Make sure that the mount is still healthy */ ret = fat_checkmount(fs); if (ret != OK) { return ret; } /* ioctl calls are just passed through to the contained block driver */ return -ENOSYS; } /**************************************************************************** * Name: fat_bind * * Description: This implements a portion of the mount operation. This * function allocates and initializes the mountpoint private data and * binds the blockdriver inode to the filesystem private data. The final * binding of the private data (containing the blockdriver) to the * mountpoint is performed by mount(). * ****************************************************************************/ static int fat_bind(FAR struct inode *blkdriver, const void *data, void **handle) { struct fat_mountpt_s *fs; int ret; /* Create an instance of the mountpt state structure */ fs = (struct fat_mountpt_s *)zalloc(sizeof(struct fat_mountpt_s)); if ( !fs ) { return -ENOMEM; } /* Initialize the allocated mountpt state structure */ fs->fs_blkdriver = blkdriver; sem_init(&fs->fs_sem, 0, 0); /* Then get information about the FAT32 filesystem on the devices managed * by this block driver. */ ret = fat_mount(fs, TRUE); if ( ret != 0 ) { sem_destroy(&fs->fs_sem); free(fs); return ret; } *handle = (void*)fs; fat_semgive(fs); return OK; } /**************************************************************************** * Name: fat_unbind * * Description: This implements the filesystem portion of the umount * operation. * ****************************************************************************/ static int fat_unbind(void *handle) { struct fat_mountpt_s *fs = (struct fat_mountpt_s*)handle; int ret; if ( !fs ) { return -EINVAL; } /* Check if there are sill any files opened on the filesystem. */ ret = OK; /* Assume success */ fat_semtake(fs); if (fs->fs_head) { /* We cannot unmount now.. there are open files */ ret = -EBUSY; } else { /* Unmount ... close the block driver */ if (fs->fs_blkdriver) { struct inode *inode = fs->fs_blkdriver; if (inode && inode->u.i_bops && inode->u.i_bops->close) { (void)inode->u.i_bops->close(inode); } } /* Release the mountpoint private data */ if (fs->fs_buffer) { free(fs->fs_buffer); } free(fs); } fat_semgive(fs); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ #endif /* CONFIG_FS_FAT */