[Fontconfig] [PATCH] fc-list: Exit with an error for invalid patterns

[W. Trevor King]

From: "W. Trevor King" <wking at tremily.us>

Instead of segfaulting as we do now:

  $ fc-list :charset=263A
  Fontconfig error: Cannot load default config file
  Segmentation fault (core dumped)
  $ gdb fc-list core
  …
  Core was generated by `fc-list :charset=263A'.
  Program terminated with signal 11, Segmentation fault.
  #0  0x00007f8b7903e7ca in FcListPatternMatchAny (p=0x0, font=0x1316568)
      at fclist.c:215
  215         for (i = 0; i < p->num; i++)
  (gdb) bt
  #0  0x00007f8b7903e7ca in FcListPatternMatchAny (p=0x0, font=0x1316568)
      at fclist.c:215
  #1  0x00007f8b7903f1a0 in IA__FcFontSetList (config=0x12da0c0,
      sets=0x7fff4959f430, nsets=1, p=0x0, os=0x12da010) at fclist.c:513
  #2  0x00007f8b7903f3b7 in IA__FcFontList (config=0x12da0c0, p=0x0,
      os=0x12da010) at fclist.c:601
  #3  0x0000000000401115 in main (argc=2, argv=0x7fff4959f598) at fc-list.c:157
  (gdb) printf "%p\n", p
  (nil)
  (gdb) up 3
  #3  0x0000000000401115 in main (argc=2, argv=0x7fff4959f598) at fc-list.c:157
  157         fs = FcFontList (0, pat, os);
  (gdb) printf "%p\n", pat
  (nil)
  (gdb) printf "%d: %s\n", argc, argv[1]
  2: :charset=263A

Now fc-list has the same invalid-pattern handling that fc-match.c has
used since ae2aafe (Fix double free (spotted by Coverity, CID #1965),
2006-04-10) and fc-pattern has used since it's creation in ba7b50a
(Add fc-pattern cmdline tool, 2010-04-20).

After this commit, all FcNameParse calls in the utility programs are
checked for invalid patterns, and the FcPatternCreate calls that
happen when no pattern is given are checked for malloc errors.
---
 fc-list/fc-list.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fc-list/fc-list.c b/fc-list/fc-list.c
index 5ad1333..4593260 100644
--- a/fc-list/fc-list.c
+++ b/fc-list/fc-list.c
@@ -148,6 +148,10 @@ main (int argc, char **argv)
     }
     else
 	pat = FcPatternCreate ();
+
+    if (!pat)
+	return 1;
+
     if (quiet && !os)
 	os = FcObjectSetCreate ();
     if (!verbose && !format && !os)
@@ -157,8 +161,7 @@ main (int argc, char **argv)
     fs = FcFontList (0, pat, os);
     if (os)
 	FcObjectSetDestroy (os);
-    if (pat)
-	FcPatternDestroy (pat);
+    FcPatternDestroy (pat);
 
     if (!quiet && fs)
     {
-- 
1.8.1.5