echfs: Add open and read functions
diff --git a/src/fs/echfs.c b/src/fs/echfs.c
index 20c1491f..95758a09 100644
--- a/src/fs/echfs.c
+++ b/src/fs/echfs.c
@@ -12,70 +12,86 @@ struct echfs_identity_table {
uint64_t block_size;
} __attribute__((packed));
-struct echfs_dir_entry {
- uint64_t parent_id;
- uint8_t type;
- char name[201];
- uint64_t atime;
- uint64_t mtime;
- uint16_t perms;
- uint16_t owner;
- uint16_t group;
- uint64_t ctime;
- uint64_t payload;
- uint64_t size;
-} __attribute__((packed));
-
#define ROOT_DIR_ID (~((uint64_t)0))
#define END_OF_CHAIN (~((uint64_t)0))
#define FILE_TYPE 0
-int load_echfs_file(int disk, int partition, void *buffer, const char *filename) {
- struct mbr_part mbr_part;
- mbr_get_part(&mbr_part, disk, partition);
+#define CACHE_ADDR ((uint8_t *)(0x1000000))
+
+static int cache_block(struct echfs_file_handle *file, uint64_t block) {
+ // Load the file.
+ uint64_t block_val = file->dir_entry.payload;
+ for (uint64_t i = 0; i < block; i++) {
+ if (block_val == END_OF_CHAIN)
+ return -1;
+
+ // Read the next block.
+ read_partition(file->disk, &file->mbr_part, &block_val, file->alloc_table_offset + block_val * sizeof(uint64_t),
+sizeof(uint64_t));
+ }
+
+ if (block_val == END_OF_CHAIN)
+ return -1;
+
+ return read_partition(file->disk, &file->mbr_part, CACHE_ADDR, block_val * file->block_size, file->block_size);
+}
+
+int echfs_read(struct echfs_file_handle *file, void *buf, uint64_t loc, uint64_t count) {
+ for (uint64_t progress = 0; progress < count;) {
+ /* cache the block */
+ uint64_t block = (loc + progress) / file->block_size;
+
+ int ret = cache_block(file, block);
+ if (ret)
+ return ret;
+
+ uint64_t chunk = count - progress;
+ uint64_t offset = (loc + progress) % file->block_size;
+ if (chunk > file->block_size - offset)
+ chunk = file->block_size - offset;
+
+ memcpy(buf + progress, &CACHE_ADDR[offset], chunk);
+ progress += chunk;
+ }
+
+ return 0;
+}
+
+int echfs_open(struct echfs_file_handle *ret, int disk, int partition, const char *filename) {
+ ret->disk = disk;
+
+ mbr_get_part(&ret->mbr_part, disk, partition);
struct echfs_identity_table id_table;
- read_partition(disk, &mbr_part, &id_table, 0, sizeof(struct echfs_identity_table));
+ read_partition(disk, &ret->mbr_part, &id_table, 0, sizeof(struct echfs_identity_table));
if (strncmp(id_table.signature, "_ECH_FS_", 8)) {
print("echfs: signature invalid\n", filename);
return -1;
}
- const uint64_t block_size = id_table.block_size;
- const uint64_t block_count = id_table.block_count;
- const uint64_t dir_length = id_table.dir_length * block_size;
- const uint64_t alloc_table_size = DIV_ROUNDUP(block_count * sizeof(uint64_t), block_size) * block_size;
- const uint64_t alloc_table_offset = 16 * block_size;
- const uint64_t dir_offset = alloc_table_offset + alloc_table_size;
+ ret->block_size = id_table.block_size;
+ ret->block_count = id_table.block_count;
+ ret->dir_length = id_table.dir_length * ret->block_size;
+ ret->alloc_table_size = DIV_ROUNDUP(ret->block_count * sizeof(uint64_t), ret->block_size) * ret->block_size;
+ ret->alloc_table_offset = 16 * ret->block_size;
+ ret->dir_offset = ret->alloc_table_offset + ret->alloc_table_size;
// Find the file in the root dir.
- struct echfs_dir_entry entry;
- for (uint64_t i = 0; i < dir_length; i += sizeof(struct echfs_dir_entry)) {
- read_partition(disk, &mbr_part, &entry, i + dir_offset, sizeof(struct echfs_dir_entry));
+ for (uint64_t i = 0; i < ret->dir_length; i += sizeof(struct echfs_dir_entry)) {
+ read_partition(disk, &ret->mbr_part, &ret->dir_entry, i + ret->dir_offset, sizeof(struct echfs_dir_entry));
- if (!entry.parent_id) {
+ if (!ret->dir_entry.parent_id) {
break;
}
- if (!strcmp(filename, entry.name) && entry.parent_id == ROOT_DIR_ID && entry.type == FILE_TYPE) {
- goto found;
+ if (!strcmp(filename, ret->dir_entry.name) &&
+ ret->dir_entry.parent_id == ROOT_DIR_ID &&
+ ret->dir_entry.type == FILE_TYPE) {
+ return 0;
}
}
print("echfs: file %s not found\n", filename);
return -1;
-
-found:;
- // Load the file.
- for (uint64_t i = entry.payload; i != END_OF_CHAIN;) {
- // Read block.
- read_partition(disk, &mbr_part, buffer, i * block_size, block_size);
- buffer += block_size;
-
- // Read the next block.
- read_partition(disk, &mbr_part, &i, alloc_table_offset + i * sizeof(uint64_t), sizeof(uint64_t));
- }
-
- return 0;
}
diff --git a/src/fs/echfs.h b/src/fs/echfs.h
index 7323e470..369212de 100644
--- a/src/fs/echfs.h
+++ b/src/fs/echfs.h
@@ -1,6 +1,36 @@
#ifndef __FS__ECHFS_H__
#define __FS__ECHFS_H__
-int load_echfs_file(int disk, int partition, void *buffer, const char *filename);
+#include <stdint.h>
+#include <lib/mbr.h>
+
+struct echfs_dir_entry {
+ uint64_t parent_id;
+ uint8_t type;
+ char name[201];
+ uint64_t atime;
+ uint64_t mtime;
+ uint16_t perms;
+ uint16_t owner;
+ uint16_t group;
+ uint64_t ctime;
+ uint64_t payload;
+ uint64_t size;
+} __attribute__((packed));
+
+struct echfs_file_handle {
+ int disk;
+ struct mbr_part mbr_part;
+ uint64_t block_size;
+ uint64_t block_count;
+ uint64_t dir_length;
+ uint64_t alloc_table_size;
+ uint64_t alloc_table_offset;
+ uint64_t dir_offset;
+ struct echfs_dir_entry dir_entry;
+};
+
+int echfs_open(struct echfs_file_handle *ret, int disk, int partition, const char *filename);
+int echfs_read(struct echfs_file_handle *file, void *buf, uint64_t loc, uint64_t count);
#endif
diff --git a/src/main.c b/src/main.c
index e83c90d0..bcb4eb4d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -21,6 +21,8 @@ extern symbol bss_end;
static int config_loaded = 0;
void main(int boot_drive) {
+ struct echfs_file_handle f;
+
// Zero out .bss section
for (uint8_t *p = bss_begin; p < bss_end; p++)
*p = 0;
@@ -43,7 +45,8 @@ void main(int boot_drive) {
} else {
print(" Found!\n");
if (!config_loaded) {
- if (!load_echfs_file(boot_drive, i, (void *)0x100000, CONFIG_NAME)) {
+ if (!echfs_open(&f, boot_drive, i, CONFIG_NAME)) {
+ echfs_read(&f, (void *)0x100000, 0, f.dir_entry.size);
config_loaded = 1;
print(" Config file found and loaded!\n");
}
@@ -77,7 +80,8 @@ void main(int boot_drive) {
}
}
- load_echfs_file(drive, part, (void *)0x100000, path);
+ echfs_open(&f, drive, part, path);
+ echfs_read(&f, (void *)0x100000, 0, f.dir_entry.size);
// Boot the kernel.
asm volatile (
