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-rw-r--r--firmware/common/file.c108
1 files changed, 70 insertions, 38 deletions
diff --git a/firmware/common/file.c b/firmware/common/file.c
index 86e1099918..41aaea570a 100644
--- a/firmware/common/file.c
+++ b/firmware/common/file.c
@@ -17,6 +17,7 @@
*
****************************************************************************/
#include <string.h>
+#include <errno.h>
#include "file.h"
#include "fat.h"
#include "types.h"
@@ -26,8 +27,10 @@
#define MAX_OPEN_FILES 4
struct filedesc {
- unsigned char sector[SECTOR_SIZE];
- int offset;
+ unsigned char cache[SECTOR_SIZE];
+ int cacheoffset;
+ int fileoffset;
+ int size;
struct fat_file fatfile;
bool busy;
};
@@ -45,6 +48,7 @@ int open(char* pathname, int flags)
if ( pathname[0] != '/' ) {
DEBUGF("'%s' is not an absolute path.\n",pathname);
DEBUGF("Only absolute pathnames supported at the moment\n");
+ errno = EINVAL;
return -1;
}
@@ -55,6 +59,7 @@ int open(char* pathname, int flags)
if ( fd == MAX_OPEN_FILES ) {
DEBUGF("Too many files open\n");
+ errno = EMFILE;
return -1;
}
@@ -72,6 +77,7 @@ int open(char* pathname, int flags)
}
if (!dir) {
DEBUGF("Failed opening dir\n");
+ errno = EIO;
return -1;
}
@@ -80,6 +86,7 @@ int open(char* pathname, int flags)
while ((entry = readdir(dir))) {
if ( !strncmp(name, entry->d_name, namelen) ) {
fat_open(entry->startcluster, &(openfiles[fd].fatfile));
+ openfiles[fd].size = entry->size;
break;
}
else {
@@ -89,11 +96,12 @@ int open(char* pathname, int flags)
closedir(dir);
if ( !entry ) {
DEBUGF("Couldn't find %s in %s\n",name,pathname);
- /* fixme: we need to use proper error codes */
+ errno = ENOENT;
return -1;
}
- openfiles[fd].offset = 0;
+ openfiles[fd].cacheoffset = 0;
+ openfiles[fd].fileoffset = 0;
openfiles[fd].busy = TRUE;
return fd;
}
@@ -109,57 +117,81 @@ int read(int fd, void* buf, int count)
int sectors;
int nread=0;
- /* are we in the middle of a cached sector? */
- if ( openfiles[fd].offset ) {
- if ( count > (SECTOR_SIZE - openfiles[fd].offset) ) {
- memcpy( buf, openfiles[fd].sector,
- SECTOR_SIZE - openfiles[fd].offset );
- openfiles[fd].offset = 0;
- nread = SECTOR_SIZE - openfiles[fd].offset;
- count -= nread;
+ if ( !openfiles[fd].busy ) {
+ errno = EBADF;
+ return -1;
+ }
+
+ /* attempt to read past EOF? */
+ if ( count > openfiles[fd].size - openfiles[fd].fileoffset )
+ count = openfiles[fd].size - openfiles[fd].fileoffset;
+
+ /* any head bytes? */
+ if ( openfiles[fd].cacheoffset ) {
+ int headbytes;
+ int offs = openfiles[fd].cacheoffset;
+ if ( count <= SECTOR_SIZE - openfiles[fd].cacheoffset ) {
+ headbytes = count;
+ openfiles[fd].cacheoffset += count;
+ if ( openfiles[fd].cacheoffset >= SECTOR_SIZE )
+ openfiles[fd].cacheoffset = 0;
}
else {
- memcpy( buf, openfiles[fd].sector, count );
- openfiles[fd].offset += count;
- nread = count;
- count = 0;
+ headbytes = SECTOR_SIZE - openfiles[fd].cacheoffset;
+ openfiles[fd].cacheoffset = 0;
}
+
+ /* eof? */
+ if ( openfiles[fd].fileoffset + headbytes > openfiles[fd].size )
+ headbytes = openfiles[fd].size - openfiles[fd].fileoffset;
+
+ memcpy( buf, openfiles[fd].cache + offs, headbytes );
+ nread = headbytes;
+ count -= headbytes;
}
/* read whole sectors right into the supplied buffer */
sectors = count / SECTOR_SIZE;
if ( sectors ) {
- if ( fat_read(&(openfiles[fd].fatfile), sectors, buf+nread ) < 0 ) {
+ int rc = fat_read(&(openfiles[fd].fatfile), sectors, buf+nread );
+ if ( rc < 0 ) {
DEBUGF("Failed reading %d sectors\n",sectors);
+ errno = EIO;
return -1;
}
- nread += sectors * SECTOR_SIZE;
- count -= sectors * SECTOR_SIZE;
- openfiles[fd].offset = 0;
+ else {
+ if ( rc > 0 ) {
+ nread += sectors * SECTOR_SIZE;
+ count -= sectors * SECTOR_SIZE;
+ }
+ else {
+ /* eof */
+ count=0;
+ }
+
+ openfiles[fd].cacheoffset = 0;
+ }
}
- /* trailing odd bytes? */
+ /* any tail bytes? */
if ( count ) {
- /* do we already have the sector cached? */
- if ( count < (SECTOR_SIZE - openfiles[fd].offset) ) {
- memcpy( buf + nread, openfiles[fd].sector, count );
- openfiles[fd].offset += count;
- nread += count;
- count = 0;
- }
- else {
- /* cache one sector and copy the trailing bytes */
- if ( fat_read(&(openfiles[fd].fatfile), 1,
- &(openfiles[fd].sector)) < 0 ) {
- DEBUGF("Failed reading odd sector\n");
- return -1;
- }
- memcpy( buf + nread, openfiles[fd].sector, count );
- openfiles[fd].offset = nread;
- nread += count;
+ if ( fat_read(&(openfiles[fd].fatfile), 1,
+ &(openfiles[fd].cache)) < 0 ) {
+ DEBUGF("Failed caching sector\n");
+ errno = EIO;
+ return -1;
}
+
+ /* eof? */
+ if ( openfiles[fd].fileoffset + count > openfiles[fd].size )
+ count = openfiles[fd].size - openfiles[fd].fileoffset;
+
+ memcpy( buf + nread, openfiles[fd].cache, count );
+ nread += count;
+ openfiles[fd].cacheoffset = count;
}
+ openfiles[fd].fileoffset += nread;
return nread;
}