Difference between revisions of "Contiki Coffee File System"
From Contiki
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(→cfs_open) |
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== cfs_open == | == cfs_open == | ||
| + | <source lang="c"> | ||
| + | typedef uint16_t packetbuf_attr_t; | ||
| + | |||
| + | struct packetbuf_attr { | ||
| + | int | ||
| + | cfs_open(const char *name, int flags) | ||
| + | { | ||
| + | int fd; | ||
| + | struct file_desc *fdp; | ||
| + | |||
| + | fd = get_available_fd(); | ||
| + | if(fd < 0) { | ||
| + | PRINTF("Coffee: Failed to allocate a new file descriptor!\n"); | ||
| + | return -1; | ||
| + | } | ||
| + | |||
| + | fdp = &coffee_fd_set[fd]; | ||
| + | fdp->flags = 0; | ||
| + | |||
| + | fdp->file = find_file(name); | ||
| + | if(fdp->file == NULL) { | ||
| + | if((flags & (CFS_READ | CFS_WRITE)) == CFS_READ) { | ||
| + | return -1; | ||
| + | } | ||
| + | fdp->file = reserve(name, page_count(COFFEE_DYN_SIZE), 1, 0); | ||
| + | if(fdp->file == NULL) { | ||
| + | return -1; | ||
| + | } | ||
| + | fdp->file->end = 0; | ||
| + | } else if(fdp->file->end == UNKNOWN_OFFSET) { | ||
| + | fdp->file->end = file_end(fdp->file->page); | ||
| + | } | ||
| + | |||
| + | fdp->flags |= flags; | ||
| + | fdp->offset = flags & CFS_APPEND ? fdp->file->end : 0; | ||
| + | fdp->file->references++; | ||
| + | |||
| + | return fd; | ||
| + | } | ||
| + | </source> | ||
Revision as of 12:56, 8 November 2014
Introduction
This tutorial is a introduction to cfs_open function of Coffee file system on Contiki OS 2.7.
You Will Learn
Through this tutorial you will learn about how the Coffee file system works.
Source Code
~/contiki-2.7/core/cfs/cfs-coffee.c ~/contiki-2.7/core/cfs/cfs-coffee.h
cfs_open
typedef uint16_t packetbuf_attr_t;
struct packetbuf_attr {
int
cfs_open(const char *name, int flags)
{
int fd;
struct file_desc *fdp;
fd = get_available_fd();
if(fd < 0) {
PRINTF("Coffee: Failed to allocate a new file descriptor!\n");
return -1;
}
fdp = &coffee_fd_set[fd];
fdp->flags = 0;
fdp->file = find_file(name);
if(fdp->file == NULL) {
if((flags & (CFS_READ | CFS_WRITE)) == CFS_READ) {
return -1;
}
fdp->file = reserve(name, page_count(COFFEE_DYN_SIZE), 1, 0);
if(fdp->file == NULL) {
return -1;
}
fdp->file->end = 0;
} else if(fdp->file->end == UNKNOWN_OFFSET) {
fdp->file->end = file_end(fdp->file->page);
}
fdp->flags |= flags;
fdp->offset = flags & CFS_APPEND ? fdp->file->end : 0;
fdp->file->references++;
return fd;
}