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/******************************************************************************
* pdf.c
*
* pdfresurrect - PDF history extraction tool
*
* Copyright (C) 2008-2010, 2012-2013, 2017-18, Matt Davis (enferex).
*
* Special thanks to all of the contributors: See AUTHORS.
*
* Special thanks to 757labs (757 crew), they are a great group
* of people to hack on projects and brainstorm with.
*
* pdf.c is part of pdfresurrect.
* pdfresurrect is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* pdfresurrect is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with pdfresurrect. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "pdf.h"
#include "main.h"
/*
* Macros
*/
/* SAFE_F
*
* Safe file read: use for fgetc() calls, this is really ugly looking.
* _fp: FILE * handle
* _expr: The expression with fgetc() in it:
*
* example: If we get a character from the file and it is ascii character 'a'
* This assumes the coder wants to store the 'a' in variable ch
* Kinda pointless if you already know that you have 'a', but for
* illustrative purposes.
*
* if (SAFE_F(my_fp, ((c=fgetc(my_fp)) == 'a')))
* do_way_cool_stuff();
*/
#define SAFE_F(_fp, _expr) \
((!ferror(_fp) && !feof(_fp) && (_expr)))
/* SAFE_E
*
* Safe expression handling. This macro is a wrapper
* that compares the result of an expression (_expr) to the expected
* value (_cmp).
*
* _expr: Expression to test.
* _cmp: Expected value, error if this returns false.
* _msg: What to say when an error occurs.
*/
#define SAFE_E(_expr, _cmp, _msg) \
do { \
if ((_expr) != (_cmp)) { \
ERR(_msg); \
exit(EXIT_FAILURE); \
} \
} while (0)
/*
* Forwards
*/
static int is_valid_xref(FILE *fp, pdf_t *pdf, xref_t *xref);
static void load_xref_entries(FILE *fp, xref_t *xref);
static void load_xref_from_plaintext(FILE *fp, xref_t *xref);
static void load_xref_from_stream(FILE *fp, xref_t *xref);
static void get_xref_linear_skipped(FILE *fp, xref_t *xref);
static void resolve_linearized_pdf(pdf_t *pdf);
static pdf_creator_t *new_creator(int *n_elements);
static void load_creator(FILE *fp, pdf_t *pdf);
static void load_creator_from_buf(FILE *fp, xref_t *xref, const char *buf);
static void load_creator_from_xml(xref_t *xref, const char *buf);
static void load_creator_from_old_format(
FILE *fp,
xref_t *xref,
const char *buf);
static char *get_object_from_here(FILE *fp, size_t *size, int *is_stream);
static char *get_object(
FILE *fp,
int obj_id,
const xref_t *xref,
size_t *size,
int *is_stream);
static void add_kid(int id, xref_t *xref);
static void load_kids(FILE *fp, int pages_id, xref_t *xref);
static const char *get_type(FILE *fp, int obj_id, const xref_t *xref);
/* static int get_page(int obj_id, const xref_t *xref); */
static char *get_header(FILE *fp);
static char *decode_text_string(const char *str, size_t str_len);
static int get_next_eof(FILE *fp);
/*
* Defined
*/
pdf_t *pdf_new(const char *name)
{
const char *n;
pdf_t *pdf;
pdf = calloc(1, sizeof(pdf_t));
if (name)
{
/* Just get the file name (not path) */
if ((n = strrchr(name, '/')))
++n;
else
n = name;
pdf->name = malloc(strlen(n) + 1);
strcpy(pdf->name, n);
}
else /* !name */
{
pdf->name = malloc(strlen("Unknown") + 1);
strcpy(pdf->name, "Unknown");
}
return pdf;
}
void pdf_delete(pdf_t *pdf)
{
int i;
for (i=0; i<pdf->n_xrefs; i++)
{
free(pdf->xrefs[i].creator);
free(pdf->xrefs[i].entries);
free(pdf->xrefs[i].kids);
}
free(pdf->name);
free(pdf->xrefs);
free(pdf);
}
int pdf_is_pdf(FILE *fp)
{
int is_pdf;
char *header;
header = get_header(fp);
if (header && strstr(header, "%PDF-"))
is_pdf = 1;
else
is_pdf = 0;
free(header);
return is_pdf;
}
void pdf_get_version(FILE *fp, pdf_t *pdf)
{
char *header, *c;
header = get_header(fp);
/* Locate version string start and make sure we dont go past header */
if ((c = strstr(header, "%PDF-")) &&
(c + strlen("%PDF-M.m") + 2))
{
pdf->pdf_major_version = atoi(c + strlen("%PDF-"));
pdf->pdf_minor_version = atoi(c + strlen("%PDF-M."));
}
free(header);
}
int pdf_load_xrefs(FILE *fp, pdf_t *pdf)
{
int i, ver, is_linear;
long pos, pos_count;
char x, *c, buf[256];
c = NULL;
/* Count number of xrefs */
pdf->n_xrefs = 0;
fseek(fp, 0, SEEK_SET);
while (get_next_eof(fp) >= 0)
++pdf->n_xrefs;
if (!pdf->n_xrefs)
return 0;
/* Load in the start/end positions */
fseek(fp, 0, SEEK_SET);
pdf->xrefs = calloc(1, sizeof(xref_t) * pdf->n_xrefs);
ver = 1;
for (i=0; i<pdf->n_xrefs; i++)
{
/* Seek to %%EOF */
if ((pos = get_next_eof(fp)) < 0)
break;
/* Set and increment the version */
pdf->xrefs[i].version = ver++;
/* Rewind until we find end of "startxref" */
pos_count = 0;
while (SAFE_F(fp, ((x = fgetc(fp)) != 'f')))
fseek(fp, pos - (++pos_count), SEEK_SET);
/* Suck in end of "startxref" to start of %%EOF */
memset(buf, 0, sizeof(buf));
SAFE_E(fread(buf, 1, pos_count, fp), pos_count,
"Failed to read startxref.\n");
c = buf;
while (*c == ' ' || *c == '\n' || *c == '\r')
++c;
/* xref start position */
pdf->xrefs[i].start = atol(c);
/* If xref is 0 handle linear xref table */
if (pdf->xrefs[i].start == 0)
get_xref_linear_skipped(fp, &pdf->xrefs[i]);
/* Non-linear, normal operation, so just find the end of the xref */
else
{
/* xref end position */
pos = ftell(fp);
fseek(fp, pdf->xrefs[i].start, SEEK_SET);
pdf->xrefs[i].end = get_next_eof(fp);
/* Look for next EOF and xref data */
fseek(fp, pos, SEEK_SET);
}
/* Check validity */
if (!is_valid_xref(fp, pdf, &pdf->xrefs[i]))
{
is_linear = pdf->xrefs[i].is_linear;
memset(&pdf->xrefs[i], 0, sizeof(xref_t));
pdf->xrefs[i].is_linear = is_linear;
rewind(fp);
get_next_eof(fp);
continue;
}
/* Load the entries from the xref */
load_xref_entries(fp, &pdf->xrefs[i]);
}
/* Now we have all xref tables, if this is linearized, we need
* to make adjustments so that things spit out properly
*/
if (pdf->xrefs[0].is_linear)
resolve_linearized_pdf(pdf);
/* Ok now we have all xref data. Go through those versions of the
* PDF and try to obtain creator information
*/
load_creator(fp, pdf);
return pdf->n_xrefs;
}
/* Load page information */
void pdf_load_pages_kids(FILE *fp, pdf_t *pdf)
{
int i, id, dummy;
char *buf, *c;
long start, sz;
start = ftell(fp);
/* Load all kids for all xref tables (versions) */
for (i=0; i<pdf->n_xrefs; i++)
{
if (pdf->xrefs[i].version && (pdf->xrefs[i].end != 0))
{
fseek(fp, pdf->xrefs[i].start, SEEK_SET);
while (SAFE_F(fp, (fgetc(fp) != 't')))
; /* Iterate to trailer */
/* Get root catalog */
sz = pdf->xrefs[i].end - ftell(fp);
buf = malloc(sz + 1);
SAFE_E(fread(buf, 1, sz, fp), sz, "Failed to load /Root.\n");
buf[sz] = '\0';
if (!(c = strstr(buf, "/Root")))
{
free(buf);
continue;
}
/* Jump to catalog (root) */
id = atoi(c + strlen("/Root") + 1);
free(buf);
buf = get_object(fp, id, &pdf->xrefs[i], NULL, &dummy);
if (!buf || !(c = strstr(buf, "/Pages")))
{
free(buf);
continue;
}
/* Start at the first Pages obj and get kids */
id = atoi(c + strlen("/Pages") + 1);
load_kids(fp, id, &pdf->xrefs[i]);
free(buf);
}
}
fseek(fp, start, SEEK_SET);
}
char pdf_get_object_status(
const pdf_t *pdf,
int xref_idx,
int entry_idx)
{
int i, curr_ver;
const xref_t *prev_xref;
const xref_entry_t *prev, *curr;
curr = &pdf->xrefs[xref_idx].entries[entry_idx];
curr_ver = pdf->xrefs[xref_idx].version;
if (curr_ver == 1)
return 'A';
/* Deleted (freed) */
if (curr->f_or_n == 'f')
return 'D';
/* Get previous version */
prev_xref = NULL;
for (i=xref_idx; i>-1; --i)
if (pdf->xrefs[i].version < curr_ver)
{
prev_xref = &pdf->xrefs[i];
break;
}
if (!prev_xref)
return '?';
/* Locate the object in the previous one that matches current one */
prev = NULL;
for (i=0; i<prev_xref->n_entries; ++i)
if (prev_xref->entries[i].obj_id == curr->obj_id)
{
prev = &prev_xref->entries[i];
break;
}
/* Added in place of a previously freed id */
if (!prev || ((prev->f_or_n == 'f') && (curr->f_or_n == 'n')))
return 'A';
/* Modified */
else if (prev->offset != curr->offset)
return 'M';
return '?';
}
void pdf_zero_object(
FILE *fp,
const pdf_t *pdf,
int xref_idx,
int entry_idx)
{
int i;
char *obj;
size_t obj_sz;
xref_entry_t *entry;
entry = &pdf->xrefs[xref_idx].entries[entry_idx];
fseek(fp, entry->offset, SEEK_SET);
/* Get object and size */
obj = get_object(fp, entry->obj_id, &pdf->xrefs[xref_idx], NULL, NULL);
i = obj_sz = 0;
while (strncmp((++i)+obj, "endobj", 6))
++obj_sz;
if (obj_sz)
obj_sz += strlen("endobj") + 1;
/* Zero object */
for (i=0; i<obj_sz; i++)
fputc('0', fp);
printf("Zeroed object %d\n", entry->obj_id);
free(obj);
}
/* Output information per version */
void pdf_summarize(
FILE *fp,
const pdf_t *pdf,
const char *name,
pdf_flag_t flags)
{
int i, j, page, n_versions, n_entries;
FILE *dst, *out;
char *dst_name, *c;
dst = NULL;
dst_name = NULL;
if (name)
{
dst_name = malloc(strlen(name) * 2 + 16);
sprintf(dst_name, "%s/%s", name, name);
if ((c = strrchr(dst_name, '.')) && (strncmp(c, ".pdf", 4) == 0))
*c = '\0';
strcat(dst_name, ".summary");
if (!(dst = fopen(dst_name, "w")))
{
ERR("Could not open file '%s' for writing\n", dst_name);
return;
}
}
/* Send output to file or stdout */
out = (dst) ? dst : stdout;
/* Count versions */
n_versions = pdf->n_xrefs;
if (n_versions && pdf->xrefs[0].is_linear)
--n_versions;
/* Ignore bad xref entry */
for (i=1; i<pdf->n_xrefs; ++i)
if (pdf->xrefs[i].end == 0)
--n_versions;
/* If we have no valid versions but linear, count that */
if (!pdf->n_xrefs || (!n_versions && pdf->xrefs[0].is_linear))
n_versions = 1;
/* Compare each object (if we dont have xref streams) */
n_entries = 0;
for (i=0; !(const int)pdf->has_xref_streams && i<pdf->n_xrefs; i++)
{
if (flags & PDF_FLAG_QUIET)
continue;
for (j=0; j<pdf->xrefs[i].n_entries; j++)
{
++n_entries;
fprintf(out,
"%s: --%c-- Version %d -- Object %d (%s)",
pdf->name,
pdf_get_object_status(pdf, i, j),
pdf->xrefs[i].version,
pdf->xrefs[i].entries[j].obj_id,
get_type(fp, pdf->xrefs[i].entries[j].obj_id,
&pdf->xrefs[i]));
/* TODO
page = get_page(pdf->xrefs[i].entries[j].obj_id, &pdf->xrefs[i]);
*/
if (0 /*page*/)
fprintf(out, " Page(%d)\n", page);
else
fprintf(out, "\n");
}
}
/* Trailing summary */
if (!(flags & PDF_FLAG_QUIET))
{
/* Let the user know that we cannot we print a per-object summary.
* If we have a 1.5 PDF using streams for xref, we have not objects
* to display, so let the user know whats up.
*/
if (pdf->has_xref_streams || !n_entries)
fprintf(out,
"%s: This PDF contains potential cross reference streams.\n"
"%s: An object summary is not available.\n",
pdf->name,
pdf->name);
fprintf(out,
"---------- %s ----------\n"
"Versions: %d\n",
pdf->name,
n_versions);
/* Count entries for summary */
if (!pdf->has_xref_streams)
for (i=0; i<pdf->n_xrefs; i++)
{
if (pdf->xrefs[i].is_linear)
continue;
n_entries = pdf->xrefs[i].n_entries;
/* If we are a linearized PDF, all versions are made from those
* objects too. So count em'
*/
if (pdf->xrefs[0].is_linear)
n_entries += pdf->xrefs[0].n_entries;
if (pdf->xrefs[i].version && n_entries)
fprintf(out,
"Version %d -- %d objects\n",
pdf->xrefs[i].version,
n_entries);
}
}
else /* Quiet output */
fprintf(out, "%s: %d\n", pdf->name, n_versions);
if (dst)
{
fclose(dst);
free(dst_name);
}
}
/* Returns '1' if we successfully display data (means its probably not xml) */
int pdf_display_creator(const pdf_t *pdf, int xref_idx)
{
int i;
if (!pdf->xrefs[xref_idx].creator)
return 0;
for (i=0; i<pdf->xrefs[xref_idx].n_creator_entries; ++i)
printf("%s: %s\n",
pdf->xrefs[xref_idx].creator[i].key,
pdf->xrefs[xref_idx].creator[i].value);
return (i > 0);
}
/* Checks if the xref is valid and sets 'is_stream' flag if the xref is a
* stream (PDF 1.5 or higher)
*/
static int is_valid_xref(FILE *fp, pdf_t *pdf, xref_t *xref)
{
int is_valid;
long start;
char *c, buf[16];
memset(buf, 0, sizeof(buf));
is_valid = 0;
start = ftell(fp);
fseek(fp, xref->start, SEEK_SET);
if (fgets(buf, 16, fp) == NULL) {
ERR("Failed to load xref string.");
exit(EXIT_FAILURE);
}
if (strncmp(buf, "xref", strlen("xref")) == 0)
is_valid = 1;
else
{
/* PDFv1.5+ allows for xref data to be stored in streams vs plaintext */
fseek(fp, xref->start, SEEK_SET);
c = get_object_from_here(fp, NULL, &xref->is_stream);
if (c && xref->is_stream)
{
free(c);
pdf->has_xref_streams = 1;
is_valid = 1;
}
}
fseek(fp, start, SEEK_SET);
return is_valid;
}
static void load_xref_entries(FILE *fp, xref_t *xref)
{
if (xref->is_stream)
load_xref_from_stream(fp, xref);
else
load_xref_from_plaintext(fp, xref);
}
static void load_xref_from_plaintext(FILE *fp, xref_t *xref)
{
int i, buf_idx, obj_id, added_entries;
char c, buf[21];
long start, pos;
start = ftell(fp);
/* Get number of entries */
pos = xref->end;
fseek(fp, pos, SEEK_SET);
while (ftell(fp) != 0)
if (SAFE_F(fp, (fgetc(fp) == '/' && fgetc(fp) == 'S')))
break;
else
SAFE_E(fseek(fp, --pos, SEEK_SET), 0, "Failed seek to xref /Size.\n");
SAFE_E(fread(buf, 1, 21, fp), 21, "Failed to load entry Size string.\n");
xref->n_entries = atoi(buf + strlen("ize "));
xref->entries = calloc(1, xref->n_entries * sizeof(struct _xref_entry));
/* Load entry data */
obj_id = 0;
fseek(fp, xref->start + strlen("xref"), SEEK_SET);
added_entries = 0;
for (i=0; i<xref->n_entries; i++)
{
/* Skip */
c = fgetc(fp);
while (c == '\n' || c == '\r')
c = fgetc(fp);
buf_idx = 0;
while (c != '\n' && c != '\r')
{
buf[buf_idx++] = c;
c = fgetc(fp);
}
buf[buf_idx] = '\0';
/* Went to far and hit start of trailer */
if (strchr(buf, 't'))
break;
/* Entry or object id */
if (strlen(buf) > 17)
{
xref->entries[i].obj_id = obj_id++;
xref->entries[i].offset = atol(strtok(buf, " "));
xref->entries[i].gen_num = atoi(strtok(NULL, " "));
xref->entries[i].f_or_n = buf[17];
++added_entries;
}
else
{
obj_id = atoi(buf);
--i;
}
}
xref->n_entries = added_entries;
fseek(fp, start, SEEK_SET);
}
/* Load an xref table from a stream (PDF v1.5 +) */
static void load_xref_from_stream(FILE *fp, xref_t *xref)
{
long start;
int is_stream;
char *stream;
size_t size;
start = ftell(fp);
fseek(fp, xref->start, SEEK_SET);
stream = NULL;
stream = get_object_from_here(fp, &size, &is_stream);
fseek(fp, start, SEEK_SET);
/* TODO: decode and analyize stream */
free(stream);
return;
}
static void get_xref_linear_skipped(FILE *fp, xref_t *xref)
{
int err;
char ch, buf[256];
if (xref->start != 0)
return;
/* Special case (Linearized PDF with initial startxref at 0) */
xref->is_linear = 1;
/* Seek to %%EOF */
if ((xref->end = get_next_eof(fp)) < 0)
return;
/* Locate the trailer */
err = 0;
while (!(err = ferror(fp)) && fread(buf, 1, 8, fp))
{
if (strncmp(buf, "trailer", strlen("trailer")) == 0)
break;
else if ((ftell(fp) - 9) < 0)
return;
fseek(fp, -9, SEEK_CUR);
}
if (err)
return;
/* If we found 'trailer' look backwards for 'xref' */
ch = 0;
while (SAFE_F(fp, ((ch = fgetc(fp)) != 'x')))
fseek(fp, -2, SEEK_CUR);
if (ch == 'x')
{
xref->start = ftell(fp) - 1;
fseek(fp, -1, SEEK_CUR);
}
/* Now continue to next eof ... */
fseek(fp, xref->start, SEEK_SET);
}
/* This must only be called after all xref and entries have been acquired */
static void resolve_linearized_pdf(pdf_t *pdf)
{
int i;
xref_t buf;
if (pdf->n_xrefs < 2)
return;
if (!pdf->xrefs[0].is_linear)
return;
/* Swap Linear with Version 1 */
buf = pdf->xrefs[0];
pdf->xrefs[0] = pdf->xrefs[1];
pdf->xrefs[1] = buf;
/* Resolve is_linear flag and version */
pdf->xrefs[0].is_linear = 1;
pdf->xrefs[0].version = 1;
pdf->xrefs[1].is_linear = 0;
pdf->xrefs[1].version = 1;
/* Adjust the other version values now */
for (i=2; i<pdf->n_xrefs; ++i)
--pdf->xrefs[i].version;
}
static pdf_creator_t *new_creator(int *n_elements)
{
pdf_creator_t *daddy;
static const pdf_creator_t creator_template[] =
{
{"Title", ""},
{"Author", ""},
{"Subject", ""},
{"Keywords", ""},
{"Creator", ""},
{"Producer", ""},
{"CreationDate", ""},
{"ModDate", ""},
{"Trapped", ""},
};
daddy = malloc(sizeof(creator_template));
memcpy(daddy, creator_template, sizeof(creator_template));
if (n_elements)
*n_elements = sizeof(creator_template) / sizeof(creator_template[0]);
return daddy;
}
#define END_OF_TRAILER(_c, _st, _fp) \
{ \
if (_c == '>') \
{ \
fseek(_fp, _st, SEEK_SET); \
continue; \
} \
}
static void load_creator(FILE *fp, pdf_t *pdf)
{
int i, buf_idx;
char c, *buf, obj_id_buf[32];
long start;
size_t sz;
start = ftell(fp);
/* For each PDF version */
for (i=0; i<pdf->n_xrefs; ++i)
{
if (!pdf->xrefs[i].version)
continue;
/* Find trailer */
fseek(fp, pdf->xrefs[i].start, SEEK_SET);
while (SAFE_F(fp, (fgetc(fp) != 't')))
; /* Iterate to "trailer" */
/* Look for "<< ....... /Info ......" */
c = '\0';
while (SAFE_F(fp, ((c = fgetc(fp)) != '>')))
if (SAFE_F(fp, ((c == '/') &&
(fgetc(fp) == 'I') && ((fgetc(fp) == 'n')))))
break;
/* Could not find /Info in trailer */
END_OF_TRAILER(c, start, fp);
while (SAFE_F(fp, (!isspace(c = fgetc(fp)) && (c != '>'))))
; /* Iterate to first white space /Info<space><data> */
/* No space between /Info and it's data */
END_OF_TRAILER(c, start, fp);
while (SAFE_F(fp, (isspace(c = fgetc(fp)) && (c != '>'))))
; /* Iterate right on top of first non-whitespace /Info data */
/* No data for /Info */
END_OF_TRAILER(c, start, fp);
/* Get obj id as number */
buf_idx = 0;
obj_id_buf[buf_idx++] = c;
while (SAFE_F(fp, (!isspace(c = fgetc(fp)) && (c != '>'))))
obj_id_buf[buf_idx++] = c;
END_OF_TRAILER(c, start, fp);
obj_id_buf[buf_idx] = '\0';
/* Get the object for the creator data. If linear, try both xrefs */
buf = get_object(fp, atoll(obj_id_buf), &pdf->xrefs[i], &sz, NULL);
if (!buf && pdf->xrefs[i].is_linear && (i+1 < pdf->n_xrefs))
buf = get_object(fp, atoll(obj_id_buf), &pdf->xrefs[i+1], &sz, NULL);
load_creator_from_buf(fp, &pdf->xrefs[i], buf);
free(buf);
}
fseek(fp, start, SEEK_SET);
}
static void load_creator_from_buf(FILE *fp, xref_t *xref, const char *buf)
{
int is_xml;
char *c;
if (!buf)
return;
/* Check to see if this is xml or old-school */
if ((c = strstr(buf, "/Type")))
while (*c && !isspace(*c))
++c;
/* Probably "Metadata" */
is_xml = 0;
if (c && (*c == 'M'))
is_xml = 1;
/* Is the buffer XML(PDF 1.4+) or old format? */
if (is_xml)
load_creator_from_xml(xref, buf);
else
load_creator_from_old_format(fp, xref, buf);
}
static void load_creator_from_xml(xref_t *xref, const char *buf)
{
/* TODO */
}
static void load_creator_from_old_format(
FILE *fp,
xref_t *xref,
const char *buf)
{
int i, n_eles, length, is_escaped, obj_id;
char *c, *ascii, *start, *s, *saved_buf_search, *obj;
pdf_creator_t *info;
info = new_creator(&n_eles);
for (i=0; i<n_eles; ++i)
{
if (!(c = strstr(buf, info[i].key)))
continue;
/* Find the value (skipping whitespace) */
c += strlen(info[i].key);
while (isspace(*c))
++c;
/* If looking at the start of a pdf token, we have gone too far */
if (*c == '/')
continue;
/* If the value is a number and not a '(' then the data is located in
* an object we need to fetch, and not inline
*/
obj = saved_buf_search = NULL;
if (isdigit(*c))
{
obj_id = atoi(c);
saved_buf_search = c;
s = saved_buf_search;
obj = get_object(fp, obj_id, xref, NULL, NULL);
c = obj;
/* Iterate to '(' */
while (c && (*c != '('))
++c;
/* Advance the search to the next token */
while (s && (*s == '/'))
++s;
saved_buf_search = s;
}
/* Find the end of the value */
start = c;
length = is_escaped = 0;
while (c && ((*c != '\r') && (*c != '\n') && (*c != '<')))
{
/* Bail out if we see an un-escaped ')' closing character */
if (!is_escaped && (*c == ')'))
break;
else if (*c == '\\')
is_escaped = 1;
else
is_escaped = 0;
++c;
++length;
}
if (length == 0)
continue;
/* Add 1 to length so it gets the closing ')' when we copy */
if (length)
length += 1;
length = (length > KV_MAX_VALUE_LENGTH) ? KV_MAX_VALUE_LENGTH : length;
strncpy(info[i].value, start, length);
info[i].value[KV_MAX_VALUE_LENGTH - 1] = '\0';
/* Restore where we were searching from */
if (saved_buf_search)
{
/* Release memory from get_object() called earlier */
free(obj);
c = saved_buf_search;
}
} /* For all creation information tags */
/* Go through the values and convert if encoded */
for (i=0; i<n_eles; ++i)
if ((ascii = decode_text_string(info[i].value, strlen(info[i].value))))
{
strncpy(info[i].value, ascii, strlen(info[i].value));
free(ascii);
}
xref->creator = info;
xref->n_creator_entries = n_eles;
}
/* Returns object data at the start of the file pointer
* This interfaces to 'get_object'
*/
static char *get_object_from_here(FILE *fp, size_t *size, int *is_stream)
{
long start;
char buf[256];
int obj_id;
xref_t xref;
xref_entry_t entry;
start = ftell(fp);
/* Object ID */
memset(buf, 0, 256);
SAFE_E(fread(buf, 1, 255, fp), 255, "Failed to load object ID.\n");
if (!(obj_id = atoi(buf)))
{
fseek(fp, start, SEEK_SET);
return NULL;
}
/* Create xref entry to pass to the get_object routine */
memset(&entry, 0, sizeof(xref_entry_t));
entry.obj_id = obj_id;
entry.offset = start;
/* Xref and single entry for the object we want data from */
memset(&xref, 0, sizeof(xref_t));
xref.n_entries = 1;
xref.entries = &entry;
fseek(fp, start, SEEK_SET);
return get_object(fp, obj_id, &xref, size, is_stream);
}
static char *get_object(
FILE *fp,
int obj_id,
const xref_t *xref,
size_t *size,
int *is_stream)
{
static const int blk_sz = 256;
int i, total_sz, read_sz, n_blks, search, stream;
size_t obj_sz;
char *c, *data;
long start;
const xref_entry_t *entry;
if (size)
*size = 0;
if (is_stream)
*is_stream = 0;
start = ftell(fp);
/* Find object */
entry = NULL;
for (i=0; i<xref->n_entries; i++)
if (xref->entries[i].obj_id == obj_id)
{
entry = &xref->entries[i];
break;
}
if (!entry)
return NULL;
/* Jump to object start */
fseek(fp, entry->offset, SEEK_SET);
/* Initial allocate */
obj_sz = 0; /* Bytes in object */
total_sz = 0; /* Bytes read in */
n_blks = 1;
data = malloc(blk_sz * n_blks);
memset(data, 0, blk_sz * n_blks);
/* Suck in data */
stream = 0;
while ((read_sz = fread(data+total_sz, 1, blk_sz-1, fp)) && !ferror(fp))
{
total_sz += read_sz;
*(data + total_sz) = '\0';
if (total_sz + blk_sz >= (blk_sz * n_blks))
data = realloc(data, blk_sz * (++n_blks));
search = total_sz - read_sz;
if (search < 0)
search = 0;
if ((c = strstr(data + search, "endobj")))
{
*(c + strlen("endobj") + 1) = '\0';
obj_sz = (void *)strstr(data + search, "endobj") - (void *)data;
obj_sz += strlen("endobj") + 1;
break;
}
else if (strstr(data, "stream"))
stream = 1;
}
clearerr(fp);
fseek(fp, start, SEEK_SET);
if (size)
*size = obj_sz;
if (is_stream)
*is_stream = stream;
return data;
}
static void add_kid(int id, xref_t *xref)
{
/* Make some space */
if (((xref->n_kids + 1) * KID_SIZE) > (xref->n_kids_allocs*KIDS_PER_ALLOC))
xref->kids = realloc(
xref->kids, (++xref->n_kids_allocs)*(KIDS_PER_ALLOC * KID_SIZE));
xref->kids[xref->n_kids++] = id;
}
/* Recursive */
static void load_kids(FILE *fp, int pages_id, xref_t *xref)
{
int dummy, buf_idx, kid_id;
char *data, *c, buf[32];
/* Get kids */
data = get_object(fp, pages_id, xref, NULL, &dummy);
if (!data || !(c = strstr(data, "/Kids")))
{
free(data);
return;
}
c = strchr(c, '[');
buf_idx = 0;
memset(buf, 0, sizeof(buf));
while (*(++c) != ']')
{
if (isdigit(*c) || (*c == ' '))
buf[buf_idx++] = *c;
else if (isalpha(*c))
{
kid_id = atoi(buf);
add_kid(kid_id, xref);
buf_idx = 0;
memset(buf, 0, sizeof(buf));
/* Check kids of kid */
load_kids(fp, kid_id, xref);
}
else if (*c == ']')
break;
}
free(data);
}
static const char *get_type(FILE *fp, int obj_id, const xref_t *xref)
{
int is_stream;
char *c, *obj, *endobj;
static char buf[32];
long start;
start = ftell(fp);
if (!(obj = get_object(fp, obj_id, xref, NULL, &is_stream)) ||
is_stream ||
!(endobj = strstr(obj, "endobj")))
{
free(obj);
fseek(fp, start, SEEK_SET);
if (is_stream)
return "Stream";
else
return "Unknown";
}
/* Get the Type value (avoiding font names like Type1) */
c = obj;
while ((c = strstr(c, "/Type")) && (c < endobj))
if (isdigit(*(c + strlen("/Type"))))
{
++c;
continue;
}
else
break;
if (!c || (c && (c > endobj)))
{
free(obj);
fseek(fp, start, SEEK_SET);
return "Unknown";
}
/* Skip to first blank/whitespace */
c += strlen("/Type");
while (isspace(*c) || *c == '/')
++c;
/* Return the value by storing it in static mem */
memcpy(buf, c, (((c - obj) < sizeof(buf)) ? c - obj : sizeof(buf)));
c = buf;
while (!(isspace(*c) || *c=='/' || *c=='>'))
++c;
*c = '\0';
free(obj);
fseek(fp, start, SEEK_SET);
return buf;
}
/* TODO
static int get_page(int obj_id, const xref_t *xref)
{
int i;
for (i=0; i<xref->n_kids; i++)
if (xref->kids[i] == obj_id)
break;
return i;
}
*/
static char *get_header(FILE *fp)
{
long start;
/* First 1024 bytes of doc must be header (1.7 spec pg 1102) */
char *header;
header = calloc(1, 1024);
start = ftell(fp);
fseek(fp, 0, SEEK_SET);
SAFE_E(fread(header, 1, 1023, fp), 1023, "Failed to load PDF header.\n");
fseek(fp, start, SEEK_SET);
return header;
}
static char *decode_text_string(const char *str, size_t str_len)
{
int idx, is_hex, is_utf16be, ascii_idx;
char *ascii, hex_buf[5] = {0};
is_hex = is_utf16be = idx = ascii_idx = 0;
/* Regular encoding */
if (str[0] == '(')
{
ascii = malloc(strlen(str) + 1);
strncpy(ascii, str, strlen(str) + 1);
return ascii;
}
else if (str[0] == '<')
{
is_hex = 1;
++idx;
}
/* Text strings can be either PDFDocEncoding or UTF-16BE */
if (is_hex && (str_len > 5) &&
(str[idx] == 'F') && (str[idx+1] == 'E') &&
(str[idx+2] == 'F') && (str[idx+3] == 'F'))
{
is_utf16be = 1;
idx += 4;
}
else
return NULL;
/* Now decode as hex */
ascii = malloc(str_len);
for ( ; idx<str_len; ++idx)
{
hex_buf[0] = str[idx++];
hex_buf[1] = str[idx++];
hex_buf[2] = str[idx++];
hex_buf[3] = str[idx];
ascii[ascii_idx++] = strtol(hex_buf, NULL, 16);
}
return ascii;
}
/* Return the offset to the beginning of the %%EOF string.
* A negative value is returned when done scanning.
*/
static int get_next_eof(FILE *fp)
{
int match, c;
const char buf[] = "%%EOF";
match = 0;
while ((c = fgetc(fp)) != EOF)
{
if (c == buf[match])
++match;
else
match = 0;
if (match == 5) /* strlen("%%EOF") */
return ftell(fp) - 5;
}
return -1;
}
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