109 lines
2.4 KiB
C
109 lines
2.4 KiB
C
#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fxgxa.h>
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/* invert_header(): Bit-invert a standard header
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Part of the header is stored inverted in files for obfuscation purposes. */
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static void invert_header(void *gxa)
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{
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uint8_t *data = gxa;
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for(size_t i = 0; i < 0x20; i++) data[i] = ~data[i];
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}
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#define fail(msg, ...) { \
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fprintf(stderr, "error: " msg ": %m\n", ##__VA_ARGS__); \
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close(fd); \
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free(data); \
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return NULL; \
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}
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/* load(): Fully load a file into memory
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Allocates a buffer with @prepend leading bytes initialized to zero. */
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static void *load(const char *filename, size_t *size, int header, int footer)
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{
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int fd;
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struct stat statbuf;
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void *data = NULL;
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size_t filesize;
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fd = open(filename, O_RDONLY);
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if(fd < 0) fail("cannot open %s", filename);
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int x = fstat(fd, &statbuf);
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if(x > 0) fail("cannot stat %s", filename);
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filesize = statbuf.st_size;
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data = malloc(header + filesize + footer);
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if(!data) fail("cannot load %s", filename);
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size_t remaining = filesize;
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while(remaining > 0)
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{
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size_t offset = header + filesize - remaining;
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ssize_t y = read(fd, data + offset, remaining);
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if(y < 0) fail("cannot read from %s", filename);
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remaining -= y;
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}
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close(fd);
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memset(data, 0, header);
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memset(data + header + filesize, 0, footer);
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if(size) *size = header + filesize + footer;
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return data;
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}
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void *load_gxa(const char *filename, size_t *size)
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{
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void *ret = load(filename, size, 0, 0);
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if(ret) invert_header(ret);
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return ret;
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}
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void *load_binary(const char *filename, size_t *size, int header, int footer)
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{
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void *ret = load(filename, size, header, footer);
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if(ret) invert_header(ret);
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return ret;
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}
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#undef fail
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#define fail(msg, ...) { \
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fprintf(stderr, "error: " msg ": %m\n", ##__VA_ARGS__); \
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rc = 1; \
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goto end; \
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}
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int save_gxa(const char *filename, void *gxa, size_t size)
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{
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/* Invert header before saving */
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invert_header(gxa);
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int rc = 0;
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int fd = creat(filename, 0644);
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if(fd < 0) fail("cannot open %s", filename);
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ssize_t status;
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size_t written = 0;
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while(written < size)
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{
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status = write(fd, gxa + written, size - written);
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if(status < 0) fail("cannot write to %s", filename);
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written += status;
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}
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end:
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/* Before returning, re-invert header for further use */
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if(fd >= 0) close(fd);
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invert_header(gxa);
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return rc;
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}
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