Seán Healy
38dfc87459
Also, can now feed image in through stdin (useful for `pv image.iso | ./revocer-pdfs ...` workflow
134 lines
3.0 KiB
C
134 lines
3.0 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#define CHUNK 4096
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#define MAX_PDF_SIZE (100LL * 1024 * 1024) // 100 MB
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int valid_pdf_header(const unsigned char *buf, size_t len) {
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if (len < 9) return 0;
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if (memcmp(buf, "%PDF-", 5) != 0)
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return 0;
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if (buf[5] < '0' || buf[5] > '9') return 0;
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if (buf[6] != '.') return 0;
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if (buf[7] < '0' || buf[7] > '9') return 0;
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size_t i = 8;
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if (buf[i] >= '0' && buf[i] <= '9') i++;
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if (buf[i] == '\r' && buf[i + 1] == '\n') return 1;
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if (buf[i] == '\n') return 1;
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return 0;
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}
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size_t find_eof(const unsigned char *buf, size_t len) {
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for (size_t i = 0; i + 5 <= len; i++) {
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if (memcmp(buf + i, "%%EOF", 5) == 0)
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return i;
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}
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return (size_t)-1;
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}
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void write_pdf(const unsigned char *data, size_t len, int idx, const char *outdir) {
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char path[512];
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snprintf(path, sizeof(path), "%s/pdf_%04d.pdf", outdir, idx);
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FILE *f = fopen(path, "wb");
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if (!f) return;
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fwrite(data, 1, len, f);
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fclose(f);
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}
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int main(int argc, char **argv) {
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if (argc != 3) {
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fprintf(stderr, "Usage: %s <image_file> <output_dir>\n", argv[0]);
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return 1;
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}
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const char *infile = argv[1];
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const char *outdir = argv[2];
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mkdir(outdir, 0755);
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if (strcmp(infile, "-") == 0) {
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infile = "/dev/stdin";
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}
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FILE *f = fopen(infile, "rb");
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if (!f) {
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perror("open input");
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return 1;
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}
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unsigned char *buf = malloc(CHUNK * 2);
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size_t buf_len = 0;
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unsigned char *pdf_buf = NULL;
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size_t pdf_size = 0;
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int collecting = 0;
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int pdf_count = 0;
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while (!feof(f)) {
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size_t r = fread(buf + buf_len, 1, CHUNK, f);
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buf_len += r;
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size_t i = 0;
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while (i < buf_len) {
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if (!collecting) {
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if (i + 10 < buf_len && valid_pdf_header(buf + i, buf_len - i)) {
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collecting = 1;
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pdf_buf = malloc(1024);
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pdf_size = 0;
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}
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}
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if (collecting) {
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// HARD SIZE LIMIT CHECK
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if (pdf_size >= MAX_PDF_SIZE) {
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free(pdf_buf);
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pdf_buf = NULL;
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pdf_size = 0;
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collecting = 0;
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continue;
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}
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if (pdf_size % 1024 == 0) {
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pdf_buf = realloc(pdf_buf, pdf_size + 1024);
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}
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pdf_buf[pdf_size++] = buf[i];
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size_t eof_pos = find_eof(pdf_buf, pdf_size);
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if (eof_pos != (size_t)-1) {
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size_t end = eof_pos + 5;
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write_pdf(pdf_buf, end, pdf_count++, outdir);
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free(pdf_buf);
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pdf_buf = NULL;
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pdf_size = 0;
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collecting = 0;
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}
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}
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i++;
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}
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buf_len = 0;
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}
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free(buf);
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fclose(f);
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return 0;
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}
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