svn commit: r300269 - stable/10/usr.bin/catman

[Don Lewis]

Author: truckman
Date: Fri May 20 06:24:16 2016
New Revision: 300269
URL: https://svnweb.freebsd.org/changeset/base/300269

Log:
  MFC r299577, r299578, r299589
  
  r299577 | truckman | 2016-05-12 16:14:31 -0700 (Thu, 12 May 2016) | 15 lines
  
  Avoid Coverity NUL termination warning about strncpy() by using
  memcpy() instead.  It's probably a bit more optimal in this case
  anyway. [1]
  
  The program logic leading up to the creation of the strncpy/memcpy
  destination buffer is a bit hairy.  Add a call to assert() to make
  it clear what is happening here and detect any potential buffer
  overruns in the future.
  
  Check a couple syscall error returns.  Ignore the EEXIST error from
  link() to preserve existing behavior. [2] [3]
  
  r299578 | truckman | 2016-05-12 16:37:58 -0700 (Thu, 12 May 2016) | 2 lines
  
  If fchdir() fails, call err() instead of warn().
  
  r299589 | truckman | 2016-05-12 22:49:02 -0700 (Thu, 12 May 2016) | 4 lines
  
  Instead of ignoring the EEXIST from link(), unconditionally unlink
  the terget before calling link().  This should prevent links to an
  old copy of the file from being retained.
  
  Reported by:	Coverity
  CID:		1009659 [1], 1009349 [2], 1009350 [3]

Modified:
  stable/10/usr.bin/catman/catman.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/usr.bin/catman/catman.c
==============================================================================
--- stable/10/usr.bin/catman/catman.c	Fri May 20 06:19:00 2016	(r300268)
+++ stable/10/usr.bin/catman/catman.c	Fri May 20 06:24:16 2016	(r300269)
@@ -34,9 +34,11 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/utsname.h>
 
+#include <assert.h>
 #include <ctype.h>
 #include <dirent.h>
 #include <err.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <locale.h>
 #include <langinfo.h>
@@ -267,7 +269,8 @@ get_cat_section(char *section)
 	char *cat_section;
 
 	cat_section = strdup(section);
-	strncpy(cat_section, "cat", 3);
+	assert(strlen(section) > 3 && strncmp(section, "man", 3) == 0);
+	memcpy(cat_section, "cat", 3);
 	return cat_section;
 }
 
@@ -419,8 +422,11 @@ process_page(char *mandir, char *src, ch
 			fprintf(stderr, "%slink %s -> %s\n",
 			    verbose ? "\t" : "", cat, link_name);
 		}
-		if (!pretend)
-			link(link_name, cat);
+		if (!pretend) {
+			(void) unlink(cat);
+			if (link(link_name, cat) < 0)
+				warn("%s %s: link", link_name, cat);
+		}
 		return;
 	}
 	insert_hashtable(links, src_ino, src_dev, strdup(cat));
@@ -608,7 +614,8 @@ select_sections(const struct dirent *ent
 static void
 process_mandir(char *dir_name, char *section)
 {
-	fchdir(starting_dir);
+	if (fchdir(starting_dir) < 0)
+		err(1, "fchdir");
 	if (already_visited(NULL, dir_name, section == NULL))
 		return;
 	check_writable(dir_name);