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fat: Fix volume label detection

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This commit is contained in:
mintsuki 2022-07-07 11:13:45 +02:00
parent 00b9f44255
commit ff5d74511a
1 changed files with 49 additions and 19 deletions
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68
common/fs/fat32.s2.c
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@ -11,11 +11,12 @@
#define FAT32_ATTRIBUTE_SUBDIRECTORY 0x10
#define FAT32_LFN_ATTRIBUTE 0x0F
#define FAT32_ATTRIBUTE_VOLLABEL 0x08
struct fat32_context {
struct volume *part;
int type;
char label[12];
char *label;
uint16_t bytes_per_sector;
uint8_t sectors_per_cluster;
uint16_t reserved_sectors;
@ -95,6 +96,8 @@ struct fat32_lfn_entry {
char name3[4];
} __attribute__((packed));
static int fat32_open_in(struct fat32_context* context, struct fat32_directory_entry* directory, struct fat32_directory_entry* file, const char* name);
static int fat32_init_context(struct fat32_context* context, struct volume *part) {
context->part = part;
@ -151,15 +154,6 @@ valid:;
context->type = 32;
}
memcpy(context->label, bpb.label, 11);
context->label[11] = 0;
// remove trailing spaces
for (int i = 10; i >= 0; i--) {
if (context->label[i] == ' ') {
context->label[i] = 0;
}
}
context->bytes_per_sector = bpb.bytes_per_sector;
context->sectors_per_cluster = bpb.sectors_per_cluster;
context->reserved_sectors = bpb.reserved_sectors;
@ -183,6 +177,31 @@ valid:;
__builtin_unreachable();
}
// get the volume label
struct fat32_directory_entry _current_directory;
struct fat32_directory_entry *current_directory;
switch (context->type) {
case 12:
case 16:
current_directory = NULL;
break;
case 32:
_current_directory.cluster_num_low = context->root_directory_cluster & 0xFFFF;
_current_directory.cluster_num_high = context->root_directory_cluster >> 16;
current_directory = &_current_directory;
break;
default:
__builtin_unreachable();
}
char *vol_label;
if (fat32_open_in(context, current_directory, (struct fat32_directory_entry *)&vol_label, NULL) == 0) {
context->label = vol_label;
} else {
context->label = NULL;
}
return 0;
}
@ -334,6 +353,25 @@ static int fat32_open_in(struct fat32_context* context, struct fat32_directory_e
break;
}
if (name == NULL) {
if (directory_entries[i].attribute != FAT32_ATTRIBUTE_VOLLABEL) {
continue;
}
char *r = ext_mem_alloc(12);
memcpy(r, directory_entries[i].file_name_and_ext, 11);
// remove trailing spaces
for (int j = 10; j >= 0; j--) {
if (r[j] == ' ') {
r[j] = 0;
continue;
}
break;
}
*((char **)file) = r;
ret = 0;
goto out;
}
if (directory_entries[i].attribute == FAT32_LFN_ATTRIBUTE) {
struct fat32_lfn_entry* lfn = (struct fat32_lfn_entry*) &directory_entries[i];
@ -399,15 +437,7 @@ char *fat32_get_label(struct volume *part) {
return NULL;
}
size_t label_len = strlen(context.label);
if (label_len == 0) {
return NULL;
}
char *ret = ext_mem_alloc(label_len + 1);
strcpy(ret, context.label);
return ret;
return context.label;
}
static void fat32_read(struct file_handle *handle, void *buf, uint64_t loc, uint64_t count);