266 lines
7.5 KiB
C
266 lines
7.5 KiB
C
#include <fs/iso9660.h>
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#include <lib/blib.h>
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#include <lib/libc.h>
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#include <mm/pmm.h>
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#define ISO9660_FIRST_VOLUME_DESCRIPTOR 0x10
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#define ISO9660_VOLUME_DESCRIPTOR_SIZE ISO9660_SECTOR_SIZE
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#define ROCK_RIDGE_MAX_FILENAME 255
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// --- Both endian structures ---
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struct BE16_t { uint16_t little, big; } __attribute__((packed));
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struct BE32_t { uint32_t little, big; } __attribute__((packed));
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// --- Directory entries ---
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struct iso9660_directory_entry {
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uint8_t length;
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uint8_t extended_attribute_length;
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struct BE32_t extent;
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struct BE32_t extent_size;
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uint8_t datetime[7];
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uint8_t flags;
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uint8_t interleaved_unit_size;
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uint8_t interleaved_gap_size;
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struct BE16_t volume_seq;
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uint8_t filename_size;
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char name[];
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} __attribute__((packed));
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// --- Volume descriptors ---
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// VDT = Volume Descriptor Type
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enum {
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ISO9660_VDT_BOOT_RECORD,
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ISO9660_VDT_PRIMARY,
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ISO9660_VDT_SUPPLEMENTARY,
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ISO9660_VDT_PARTITION_DESCRIPTOR,
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ISO9660_VDT_TERMINATOR = 255
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};
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struct iso9660_volume_descriptor {
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uint8_t type;
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char identifier[5];
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uint8_t version;
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} __attribute__((packed));
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struct iso9660_primary_volume {
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struct iso9660_volume_descriptor volume_descriptor;
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union {
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struct {
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uint8_t unused0[1];
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char system_identifier[32];
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char volume_identifier[32];
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uint8_t unused1[8];
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struct BE32_t space_size;
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uint8_t unused2[32];
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struct BE16_t set_size;
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struct BE16_t volume_seq;
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struct BE16_t LBA_size;
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struct BE32_t path_table_size;
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uint32_t LBA_path_table_little;
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uint32_t LBA_optional_path_table_little;
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uint32_t LBA_path_table_big;
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uint32_t LBA_optional_path_table_big;
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struct iso9660_directory_entry root;
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} __attribute__((packed));
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uint8_t padding[2041];
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};
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} __attribute__((packed));
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// --- Implementation ---
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struct iso9660_contexts_node {
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struct iso9660_context context;
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struct iso9660_contexts_node *next;
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};
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static struct iso9660_contexts_node *contexts = NULL;
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static void iso9660_find_PVD(struct iso9660_volume_descriptor *desc, struct volume *vol) {
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uint32_t lba = ISO9660_FIRST_VOLUME_DESCRIPTOR;
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while (true) {
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volume_read(vol, desc, lba * ISO9660_SECTOR_SIZE, ISO9660_SECTOR_SIZE);
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switch (desc->type) {
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case ISO9660_VDT_PRIMARY:
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return;
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case ISO9660_VDT_TERMINATOR:
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panic(false, "ISO9660: no primary volume descriptor");
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break;
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}
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++lba;
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}
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}
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static void iso9660_cache_root(struct volume *vol,
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void **root,
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uint32_t *root_size) {
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struct iso9660_primary_volume pv;
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iso9660_find_PVD((struct iso9660_volume_descriptor *)&pv, vol);
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*root_size = pv.root.extent_size.little;
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*root = ext_mem_alloc(*root_size);
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volume_read(vol, *root, pv.root.extent.little * ISO9660_SECTOR_SIZE, *root_size);
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}
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static struct iso9660_context *iso9660_get_context(struct volume *vol) {
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struct iso9660_contexts_node *current = contexts;
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while (current) {
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if (current->context.vol == vol)
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return ¤t->context;
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current = current->next;
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}
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// The context is not cached at this point
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struct iso9660_contexts_node *node = ext_mem_alloc(sizeof(struct iso9660_contexts_node));
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node->context.vol = vol;
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iso9660_cache_root(vol, &node->context.root, &node->context.root_size);
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node->next = contexts;
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contexts = node;
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return &node->context;
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}
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static bool load_name(char *buf, struct iso9660_directory_entry *entry) {
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unsigned char* sysarea = ((unsigned char*)entry) + sizeof(struct iso9660_directory_entry) + entry->filename_size;
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int sysarea_len = entry->length - sizeof(struct iso9660_directory_entry) - entry->filename_size;
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if ((entry->filename_size & 0x1) == 0) {
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sysarea++;
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sysarea_len--;
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}
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int rrnamelen = 0;
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while ((sysarea_len >= 4) && ((sysarea[3] == 1) || (sysarea[2] == 2))) {
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if (sysarea[0] == 'N' && sysarea[1] == 'M') {
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rrnamelen = sysarea[2] - 5;
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break;
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}
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sysarea_len -= sysarea[2];
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sysarea += sysarea[2];
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}
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size_t name_len = 0;
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if (rrnamelen) {
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/* rock ridge naming scheme */
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name_len = rrnamelen;
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memcpy(buf, sysarea + 5, name_len);
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buf[name_len] = 0;
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return true;
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} else {
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name_len = entry->filename_size;
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size_t j;
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for (j = 0; j < name_len; j++) {
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if (entry->name[j] == ';')
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break;
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if (entry->name[j] == '.' && entry->name[j+1] == ';')
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break;
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buf[j] = entry->name[j];
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}
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buf[j] = 0;
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return false;
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}
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}
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static struct iso9660_directory_entry *iso9660_find(void *buffer, uint32_t size, const char *filename) {
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while (size) {
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struct iso9660_directory_entry *entry = buffer;
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if (entry->length == 0) {
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if (size <= ISO9660_SECTOR_SIZE)
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return NULL;
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size_t prev_size = size;
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size = ALIGN_DOWN(size, ISO9660_SECTOR_SIZE);
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buffer += prev_size - size;
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continue;
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}
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char entry_filename[128];
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bool rr = load_name(entry_filename, entry);
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if (rr) {
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if (strcmp(filename, entry_filename) == 0) {
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return buffer;
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}
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} else {
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if (strcasecmp(filename, entry_filename) == 0) {
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return buffer;
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}
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}
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size -= entry->length;
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buffer += entry->length;
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}
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return NULL;
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}
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// --- Public functions ---
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int iso9660_check_signature(struct volume *vol) {
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char buf[6];
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const uint64_t signature = ISO9660_FIRST_VOLUME_DESCRIPTOR * ISO9660_SECTOR_SIZE + 1;
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volume_read(vol, buf, signature, 5);
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buf[5] = '\0';
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return !strcmp(buf, "CD001");
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}
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bool iso9660_open(struct iso9660_file_handle *ret, struct volume *vol, const char *path) {
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ret->context = iso9660_get_context(vol);
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while (*path == '/')
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++path;
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struct iso9660_directory_entry *current = ret->context->root;
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uint32_t current_size = ret->context->root_size;
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bool first = true;
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uint32_t next_sector = 0;
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uint32_t next_size = 0;
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char filename[ROCK_RIDGE_MAX_FILENAME];
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while (true) {
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char *aux = filename;
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while (!(*path == '/' || *path == '\0'))
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*aux++ = *path++;
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*aux = '\0';
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struct iso9660_directory_entry *entry = iso9660_find(current, current_size, filename);
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if (!entry)
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return false; // Not found :(
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next_sector = entry->extent.little;
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next_size = entry->extent_size.little;
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if (*path++ == '\0')
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break; // Found :)
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if (!first) {
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pmm_free(current, current_size);
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}
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current_size = next_size;
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current = ext_mem_alloc(current_size);
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first = false;
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volume_read(vol, current, next_sector * ISO9660_SECTOR_SIZE, current_size);
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}
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ret->LBA = next_sector;
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ret->size = next_size;
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return true;
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}
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void iso9660_read(struct iso9660_file_handle *file, void *buf, uint64_t loc, uint64_t count) {
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volume_read(file->context->vol, buf, file->LBA * ISO9660_SECTOR_SIZE + loc, count);
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}
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void iso9660_close(struct iso9660_file_handle *file) {
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pmm_free(file, sizeof(struct iso9660_file_handle));
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}
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