44 lines
1.3 KiB
C
44 lines
1.3 KiB
C
#include "fs.h"
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#include "../lib/string.h"
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#include "../drivers/ata.h"
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enum {
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fs_start = 1, // sector where the FS starts
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};
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int stat(const char* name, struct stat *buf) {
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struct dir dir;
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read_sectors_ATA_PIO(&dir, fs_start, 1);
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for (int i = 0; i < ents_in_dir; ++i) {
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struct dirent *e = &dir.entries[i];
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if (!strncmp(e->name, name, sizeof(e->name))) {
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buf->size = e->size_bytes;
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buf->reserved[0] = e->offset_sectors;
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return 0;
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}
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}
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return -1;
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}
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/* Find file by name and read it into buffer with size bufsize.
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* At most (bufsize & -512) bytes will be read.
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* Return number of bytes read or -1 on failure. */
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int read_file(const char* name, void* buf, uint32_t bufsize) {
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struct stat statbuf;
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if (stat(name, &statbuf) != 0) {
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return -1;
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}
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uint32_t sector = fs_start + statbuf.reserved[0];
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uint32_t bytes_read = 0;
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uint32_t file_sectors = (statbuf.size + sector_size - 1) / sector_size;
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while (bufsize >= sector_size && file_sectors > 0) {
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read_sectors_ATA_PIO(buf, sector, 1);
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sector++;
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file_sectors--;
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bufsize -= sector_size;
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buf += sector_size;
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bytes_read += sector_size;
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}
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return bytes_read < statbuf.size ? bytes_read : statbuf.size;
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}
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