diff options
Diffstat (limited to 'source/pdf/pdf-write.c')
| -rw-r--r-- | source/pdf/pdf-write.c | 119 |
1 files changed, 118 insertions, 1 deletions
diff --git a/source/pdf/pdf-write.c b/source/pdf/pdf-write.c index a161c763..fd126aac 100644 --- a/source/pdf/pdf-write.c +++ b/source/pdf/pdf-write.c @@ -2270,6 +2270,117 @@ static void dump_object_details(pdf_document *doc, pdf_write_options *opts) } #endif +static void presize_unsaved_signature_byteranges(pdf_document *doc) +{ + if (doc->unsaved_sigs) + { + /* The ByteRange objects of signatures are initially written out with + * dummy values, and then overwritten later. We need to make sure their + * initial form at least takes enough sufficient file space */ + pdf_unsaved_sig *usig; + int n = 0; + + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + n++; + + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + { + /* There will be segments of bytes at the beginning, at + * the end and between each consecutive pair of signatures, + * hence n + 1 */ + int i; + pdf_obj *byte_range = pdf_dict_getp(usig->field, "V/ByteRange"); + + for (i = 0; i < n+1; i++) + { + pdf_array_push_drop(byte_range, pdf_new_int(doc, INT_MAX)); + pdf_array_push_drop(byte_range, pdf_new_int(doc, INT_MAX)); + } + } + } +} + +static void complete_signatures(pdf_document *doc, pdf_write_options *opts, char *filename) +{ + fz_context *ctx = doc->ctx; + pdf_unsaved_sig *usig; + FILE *f; + char buf[5120]; + int i; + int flen; + int last_end; + + if (doc->unsaved_sigs) + { + pdf_obj *byte_range; + + f = fopen(filename, "rb+"); + if (!f) + fz_throw(ctx, FZ_ERROR_GENERIC, "Failed to open %s to complete signatures", filename); + + fseek(f, 0, SEEK_END); + flen = ftell(f); + + /* Locate the byte ranges and contents in the saved file */ + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + { + char *bstr, *cstr, *fstr; + int pnum = pdf_obj_parent_num(pdf_dict_getp(usig->field, "V/ByteRange")); + fseek(f, opts->ofs_list[pnum], SEEK_SET); + (void)fread(buf, 1, sizeof(buf), f); + buf[sizeof(buf)-1] = 0; + + bstr = strstr(buf, "/ByteRange"); + cstr = strstr(buf, "/Contents"); + fstr = strstr(buf, "/Filter"); + + if (bstr && cstr && fstr && bstr < cstr && cstr < fstr) + { + usig->byte_range_start = bstr - buf + 10 + opts->ofs_list[pnum]; + usig->byte_range_end = cstr - buf + opts->ofs_list[pnum]; + usig->contents_start = cstr - buf + 9 + opts->ofs_list[pnum]; + usig->contents_end = fstr - buf + opts->ofs_list[pnum]; + } + } + + /* Recreate ByteRange with correct values. Initially store the + * recreated object in the first of the unsaved signatures */ + byte_range = pdf_new_array(doc, 4); + pdf_dict_putp_drop(doc->unsaved_sigs->field, "V/ByteRange", byte_range); + + last_end = 0; + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + { + pdf_array_push_drop(byte_range, pdf_new_int(doc, last_end)); + pdf_array_push_drop(byte_range, pdf_new_int(doc, usig->contents_start - last_end)); + last_end = usig->contents_end; + } + pdf_array_push_drop(byte_range, pdf_new_int(doc, last_end)); + pdf_array_push_drop(byte_range, pdf_new_int(doc, flen - last_end)); + + /* Copy the new ByteRange to the other unsaved signatures */ + for (usig = doc->unsaved_sigs->next; usig; usig = usig->next) + pdf_dict_putp_drop(usig->field, "V/ByteRange", pdf_copy_array(byte_range)); + + /* Write the byte range into buf, padding with spaces*/ + i = pdf_sprint_obj(buf, sizeof(buf), byte_range, 1); + memset(buf+i, ' ', sizeof(buf)-i); + + /* Write the byte range to the file */ + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + { + fseek(f, usig->byte_range_start, SEEK_SET); + fwrite(buf, 1, usig->byte_range_end - usig->byte_range_start, f); + } + + fclose(f); + + /* Write the digests into the file */ + for (usig = doc->unsaved_sigs; usig; usig = usig->next) + pdf_write_digest(doc, filename, byte_range, usig->contents_start, usig->contents_end - usig->contents_start, usig->signer); + } +} + void pdf_write_document(pdf_document *doc, char *filename, fz_write_options *fz_opts) { int lastfree; @@ -2285,6 +2396,7 @@ void pdf_write_document(pdf_document *doc, char *filename, fz_write_options *fz_ ctx = doc->ctx; pdf_finish_edit(doc); + presize_unsaved_signature_byteranges(doc); xref_len = pdf_xref_len(doc); @@ -2415,6 +2527,10 @@ void pdf_write_document(pdf_document *doc, char *filename, fz_write_options *fz_ writexref(doc, &opts, 0, xref_len, 1, 0, opts.first_xref_offset); } + fclose(opts.out); + opts.out = NULL; + complete_signatures(doc, &opts, filename); + doc->dirty = 0; } fz_always(ctx) @@ -2439,7 +2555,8 @@ void pdf_write_document(pdf_document *doc, char *filename, fz_write_options *fz_ pdf_drop_obj(opts.hints_s); pdf_drop_obj(opts.hints_length); page_objects_list_destroy(ctx, opts.page_object_lists); - fclose(opts.out); + if (opts.out) + fclose(opts.out); doc->freeze_updates = 0; } fz_catch(ctx) |