wdvi

commit 6a793481211ba1d88161cb1edfb06668cd968833
parent 5ae2d85a7d48cba02d6aacaaccc2a24bf74a0bf7
Author: Kyle Milz <krwmilz@gmail.com>
Date:   Tue, 14 Sep 2021 01:42:30 +0000

add error checking to fseek()

Diffstat:
M
dvi-init.c
 | 
34
+++++++++++++++++++++++-----------

1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/dvi-init.c b/dvi-init.c
@@ -28,6 +28,7 @@ NOTE:
 \*========================================================================*/
 
 #include <err.h>
+#include <stdio.h>	/* fseek() */
 
 #include <X11/Shell.h>	/* defines XtNtitle and XtNiconName */
 
@@ -503,10 +504,12 @@ find_postamble()
 	ubyte	*p1;
 	ubyte	byte;
 
-	fseek(dvi_file, (long) 0, 2);
+	if (fseek(dvi_file, 0, SEEK_END) != 0)
+		err(1, "fseek");
 	pos = ftell(dvi_file) - TMPSIZ;
 	if (pos < 0) pos = 0;
-	fseek(dvi_file, pos, 0);
+	if (fseek(dvi_file, pos, SEEK_SET) != 0)
+		err(1, "fseek");
 	p = temp + fread((char *) temp, sizeof(char), TMPSIZ, dvi_file);
 	for (;;) {
 	    p1 = p;
@@ -521,14 +524,17 @@ find_postamble()
 	pos += p - temp;
 	byte = *p;
 	while (byte == TRAILER) {
-	    fseek(dvi_file, --pos, 0);
+	    if (fseek(dvi_file, --pos, SEEK_SET) != 0)
+		err(1, "fseek");
 	    byte = one(dvi_file);
 	}
 	if (byte != 2)
 	    /* Wrong version of DVI output for this program */
 	    return False;
-	fseek(dvi_file, pos - 4, 0);
-	fseek(dvi_file, sfour(dvi_file), 0);
+	if (fseek(dvi_file, pos - 4, SEEK_SET) != 0)
+		err(1, "fseek");
+	if (fseek(dvi_file, sfour(dvi_file), SEEK_SET) != 0)
+		err(1, "fseek");
 
 	return True;
 }
@@ -664,7 +670,7 @@ prepare_pages()
 {
 	int i;
 
-	page_info = xmalloc((unsigned) (total_pages + 1) * sizeof *page_info);
+	page_info = xmalloc((unsigned) (total_pages + 1) * sizeof(*page_info));
 	page_info->pw = unshrunk_paper_w;
 	page_info->ph = unshrunk_paper_h;
 	page_info->ww = dvi_unshrunk_page_w;
@@ -673,14 +679,18 @@ prepare_pages()
 
 	i = total_pages;
 	page_info[--i].offset = last_page_offset;
-	fseek(dvi_file, last_page_offset, 0);
+	if (fseek(dvi_file, last_page_offset, SEEK_SET) != 0)
+		err(1, "fseek");
 	/*
 	 * Follow back pointers through pages in the DVI file,
 	 * storing the offsets in the page_info[].offset table.
 	 */
 	while (i > 0) {
-	    fseek(dvi_file, (long) (1+4+(9*4)), 1);
-	    fseek(dvi_file, page_info[--i].offset = four(dvi_file), 0);
+		if (fseek(dvi_file, (long) (1+4+(9*4)), SEEK_CUR) != 0)
+			err(1, "fseek");
+		if (fseek(dvi_file, page_info[--i].offset = four(dvi_file),
+		    SEEK_SET) != 0)
+			err(1, "fseek");
 	}
 }
 
@@ -749,7 +759,8 @@ init_dvi_file()
 		goto err;
 
 	prepare_pages();
-	if (current_page >= total_pages) current_page = total_pages - 1;
+	if (current_page >= total_pages)
+		current_page = total_pages - 1;
 	warn_spec_now = warn_spec;
 	init_prescan();
 	set_titles();
@@ -797,7 +808,8 @@ reload_dvi_file()
 	for (fontp = font_head; fontp != NULL; fontp = fontp->next)
 	    fontp->flags &= ~FONT_IN_USE;
 
-	fseek(dvi_file, (long) 0, 0);
+	if (fseek(dvi_file, 0, SEEK_SET) != 0)
+		err(1, "fseek");
 	if (!init_dvi_file())
 		return False;
 	if (list_fonts)