Add salt attribute to dir and remap-dir elements

'salt' attribute affects a cache filename to generate different name from directory name.
This is useful when sharing caches with host on sandbox and/or give a filename differently:

    <dir salt="randomdata">/usr/share/fonts</dir>
    <remap-dir as-path="/usr/share/fonts" salt="salt for /usr/share/fonts on host">/run/host/fonts</remap-dir>

Applications can read caches as-is for fonts on /run/host/fonts where is mounted from host.
and write a cache for their own fonts on /usr/share/fonts with different name.

src/fccache.c

@@ -152,14 +152,25 @@ FcDirCacheBasenameMD5 (FcConfig *config, const FcChar8 *dir, FcChar8 cache_base[
 {
     FcChar8		*new_dir;
     unsigned char 	hash[16];
-    FcChar8		*hex_hash;
+    FcChar8		*hex_hash, *key = NULL;
     int			cnt;
     struct MD5Context 	ctx;
+    const FcChar8	*salt;
 
+    salt = FcConfigMapSalt (config, dir);
     new_dir = FcConfigMapFontPath(config, dir);
     if (new_dir)
 	dir = new_dir;
+    if (salt)
+    {
+	size_t dl = strlen ((const char *) dir);
+	size_t sl = strlen ((const char *) salt);
 
+	key = (FcChar8 *) malloc (dl + sl + 1);
+	memcpy (key, dir, dl);
+	memcpy (key + dl, salt, sl + 1);
+	dir = key;
+    }
     MD5Init (&ctx);
     MD5Update (&ctx, (const unsigned char *)dir, strlen ((const char *) dir));
 
@@ -167,6 +178,8 @@ FcDirCacheBasenameMD5 (FcConfig *config, const FcChar8 *dir, FcChar8 cache_base[
 
     if (new_dir)
 	FcStrFree(new_dir);
+    if (key)
+	FcStrFree (key);
 
     cache_base[0] = '/';
     hex_hash = cache_base + 1;

src/fccfg.c

@@ -540,9 +540,10 @@ FcConfigGetConfigDirs (FcConfig   *config)
 FcBool
 FcConfigAddFontDir (FcConfig	    *config,
 		    const FcChar8   *d,
-		    const FcChar8   *m)
+		    const FcChar8   *m,
+		    const FcChar8   *salt)
 {
-    return FcStrSetAddFilenamePair (config->fontDirs, d, m);
+    return FcStrSetAddFilenamePairWithSalt (config->fontDirs, d, m, salt);
 }
 
 FcBool
@@ -587,7 +588,7 @@ FcConfigMapFontPath(FcConfig		*config,
 {
     FcStrList	*list;
     FcChar8	*dir;
-    FcChar8	*map;
+    const FcChar8 *map;
     FcChar8     *retval;
 
     list = FcConfigGetFontDirs(config);
@@ -599,7 +600,7 @@ FcConfigMapFontPath(FcConfig		*config,
     FcStrListDone(list);
     if (!dir)
 	return 0;
-    map = FcStrPairSecond(dir);
+    map = FcStrTripleSecond(dir);
     if (!map)
 	return 0;
     retval = FcStrBuildFilename(map, path + strlen((char *) dir), NULL);
@@ -615,6 +616,26 @@ FcConfigMapFontPath(FcConfig		*config,
     return retval;
 }
 
+const FcChar8 *
+FcConfigMapSalt (FcConfig      *config,
+		 const FcChar8 *path)
+{
+    FcStrList *list;
+    FcChar8 *dir;
+
+    list = FcConfigGetFontDirs (config);
+    if (!list)
+	return NULL;
+    while ((dir = FcStrListNext (list)))
+	if (FcConfigPathStartsWith (path, dir))
+	    break;
+    FcStrListDone (list);
+    if (!dir)
+	return NULL;
+
+    return FcStrTripleThird (dir);
+}
+
 FcBool
 FcConfigAddCacheDir (FcConfig	    *config,
 		     const FcChar8  *d)

src/fcint.h

@@ -660,7 +660,8 @@ FcConfigAddConfigDir (FcConfig	    *config,
 FcPrivate FcBool
 FcConfigAddFontDir (FcConfig	    *config,
 		    const FcChar8   *d,
-		    const FcChar8   *m);
+		    const FcChar8   *m,
+		    const FcChar8   *salt);
 
 FcPrivate FcBool
 FcConfigResetFontDirs (FcConfig *config);
@@ -669,6 +670,10 @@ FcPrivate FcChar8 *
 FcConfigMapFontPath(FcConfig		*config,
 		    const FcChar8	*path);
 
+FcPrivate const FcChar8 *
+FcConfigMapSalt (FcConfig      *config,
+		 const FcChar8 *path);
+
 FcPrivate FcBool
 FcConfigAddCacheDir (FcConfig	    *config,
 		     const FcChar8  *d);
@@ -1245,13 +1250,16 @@ FcPrivate void
 FcStrSetSort (FcStrSet * set);
 
 FcPrivate FcBool
-FcStrSetAddPair (FcStrSet *set, const FcChar8 *a, const FcChar8 *b);
+FcStrSetAddTriple (FcStrSet *set, const FcChar8 *a, const FcChar8 *b, const FcChar8 *c);
 
-FcPrivate FcChar8 *
+FcPrivate const FcChar8 *
-FcStrPairSecond (FcChar8 *s);
+FcStrTripleSecond (FcChar8 *s);
+
+FcPrivate const FcChar8 *
+FcStrTripleThird (FcChar8 *str);
 
 FcPrivate FcBool
-FcStrSetAddFilenamePair (FcStrSet *strs, const FcChar8 *d, const FcChar8 *m);
+FcStrSetAddFilenamePairWithSalt (FcStrSet *strs, const FcChar8 *d, const FcChar8 *m, const FcChar8 *salt);
 
 FcPrivate FcBool
 FcStrSetDeleteAll (FcStrSet *set);

src/fcstr.c

@@ -37,11 +37,12 @@ FcStrCopy (const FcChar8 *s)
 }
 
 static FcChar8 *
-FcStrMakePair (const FcChar8 *s1, const FcChar8 *s2)
+FcStrMakeTriple (const FcChar8 *s1, const FcChar8 *s2, const FcChar8 *s3)
 {
     int	    s1l = s1 ? strlen ((char *) s1) : 0;
     int	    s2l = s2 ? strlen ((char *) s2) : 0;
-    int	    l = s1l + 1 + s2l + 1;
+    int     s3l = s3 ? strlen ((char *) s3) : 0;
+    int	    l = s1l + 1 + s2l + 1 + s3l + 1;
     FcChar8 *s = malloc (l);
 
     if (!s)
@@ -54,6 +55,10 @@ FcStrMakePair (const FcChar8 *s1, const FcChar8 *s2)
 	memcpy (s + s1l + 1, s2, s2l + 1);
     else
 	s[s1l + 1] = '\0';
+    if (s3)
+	memcpy (s + s1l + 1 + s2l + 1, s3, s3l + 1);
+    else
+	s[s1l + 1 + s2l + 1] = '\0';
     return s;
 }
 
@@ -1255,9 +1260,9 @@ FcStrSetAdd (FcStrSet *set, const FcChar8 *s)
 }
 
 FcBool
-FcStrSetAddPair (FcStrSet *set, const FcChar8 *a, const FcChar8 *b)
+FcStrSetAddTriple (FcStrSet *set, const FcChar8 *a, const FcChar8 *b, const FcChar8 *c)
 {
-    FcChar8 *new = FcStrMakePair (a, b);
+    FcChar8 *new = FcStrMakeTriple (a, b, c);
     if (!new)
 	return FcFalse;
     if (!_FcStrSetAppend (set, new))
@@ -1268,8 +1273,8 @@ FcStrSetAddPair (FcStrSet *set, const FcChar8 *a, const FcChar8 *b)
     return FcTrue;
 }
 
-FcChar8 *
+const FcChar8 *
-FcStrPairSecond (FcChar8 *str)
+FcStrTripleSecond (FcChar8 *str)
 {
     FcChar8 *second = str + strlen((char *) str) + 1;
 
@@ -1278,6 +1283,17 @@ FcStrPairSecond (FcChar8 *str)
     return second;
 }
 
+const FcChar8 *
+FcStrTripleThird (FcChar8 *str)
+{
+    FcChar8 *second = str + strlen ((char *) str) + 1;
+    FcChar8 *third = second + strlen ((char *) second) + 1;
+
+    if (*third == '\0')
+	return 0;
+    return third;
+}
+
 FcBool
 FcStrSetAddFilename (FcStrSet *set, const FcChar8 *s)
 {
@@ -1293,7 +1309,7 @@ FcStrSetAddFilename (FcStrSet *set, const FcChar8 *s)
 }
 
 FcBool
-FcStrSetAddFilenamePair (FcStrSet *set, const FcChar8 *a, const FcChar8 *b)
+FcStrSetAddFilenamePairWithSalt (FcStrSet *set, const FcChar8 *a, const FcChar8 *b, const FcChar8 *salt)
 {
     FcChar8 *new_a = NULL;
     FcChar8 *new_b = NULL;
@@ -1315,7 +1331,7 @@ FcStrSetAddFilenamePair (FcStrSet *set, const FcChar8 *a, const FcChar8 *b)
 	    return FcFalse;
 	}
     }
-    ret = FcStrSetAddPair (set, new_a, new_b);
+    ret = FcStrSetAddTriple (set, new_a, new_b, salt);
     if (new_a)
 	FcStrFree (new_a);
     if (new_b)

src/fcxml.c

@@ -2057,7 +2057,7 @@ FcParseDescription (FcConfigParse *parse)
 static void
 FcParseRemapDir (FcConfigParse *parse)
 {
-    const FcChar8 *path, *attr, *data;
+    const FcChar8 *path, *attr, *data, *salt;
     FcChar8 *prefix = NULL;
 
     data = FcStrBufDoneStatic (&parse->pstack->str);
@@ -2073,12 +2073,13 @@ FcParseRemapDir (FcConfigParse *parse)
 	return;
     }
     attr = FcConfigGetAttribute (parse, "prefix");
+    salt = FcConfigGetAttribute (parse, "salt");
     prefix = _get_real_path_from_prefix (parse, data, attr);
     if (!prefix || prefix[0] == 0)
 	FcConfigMessage (parse, FcSevereWarning, "empty font directory name for remap ignored");
     else if (!parse->scanOnly && (!FcStrUsesHome (prefix) || FcConfigHome ()))
     {
-	if (!FcConfigAddFontDir (parse->config, prefix, path))
+	if (!FcConfigAddFontDir (parse->config, prefix, path, salt))
 	    FcConfigMessage (parse, FcSevereError, "out of memory; cannot create remap data for %s as %s", prefix, path);
     }
     FcStrBufDestroy (&parse->pstack->str);
@@ -2237,7 +2238,7 @@ FcParseUnary (FcConfigParse *parse, FcOp op)
 static void
 FcParseDir (FcConfigParse *parse)
 {
-    const FcChar8 *attr, *data;
+    const FcChar8 *attr, *data, *salt;
     FcChar8 *prefix = NULL;
 
     data = FcStrBufDoneStatic (&parse->pstack->str);
@@ -2247,12 +2248,13 @@ FcParseDir (FcConfigParse *parse)
 	return;
     }
     attr = FcConfigGetAttribute (parse, "prefix");
+    salt = FcConfigGetAttribute (parse, "salt");
     prefix = _get_real_path_from_prefix (parse, data, attr);
     if (!prefix || prefix[0] == 0)
 	FcConfigMessage (parse, FcSevereWarning, "empty font directory name ignored");
     else if (!parse->scanOnly && (!FcStrUsesHome (prefix) || FcConfigHome ()))
     {
-	if (!FcConfigAddFontDir (parse->config, prefix, NULL))
+	if (!FcConfigAddFontDir (parse->config, prefix, NULL, salt))
 	    FcConfigMessage (parse, FcSevereError, "out of memory; cannot add directory %s", prefix);
     }
     FcStrBufDestroy (&parse->pstack->str);

test/run-test.sh

@@ -172,6 +172,53 @@ if cmp flist1 flist2 > /dev/null ; then : ; else
   exit 1
 fi
 rm -rf $TESTTMPDIR out1 out2 xxx flist1 flist2 bind-fonts.conf
+
+dotest "Different directory content between host and sandbox"
+prep
+cp $FONT1 $FONTDIR
+$FCCACHE $FONTDIR
+sleep 1
+ls -1 --color=no $CACHEDIR/*cache*> out1
+stat -c '%n %s %y %z' `cat out1` > stat1
+TESTTMPDIR=`mktemp -d /tmp/fontconfig.XXXXXXXX`
+TESTTMP2DIR=`mktemp -d /tmp/fontconfig.XXXXXXXX`
+cp $FONT2 $TESTTMP2DIR
+sed "s!@FONTDIR@!$TESTTMPDIR/fonts</dir><dir salt="'"'"salt-to-make-different"'"'">$FONTDIR!
+s!@REMAPDIR@!<remap-dir as-path="'"'"$FONTDIR"'"'">$TESTTMPDIR/fonts</remap-dir>!
+s!@CACHEDIR@!$TESTTMPDIR/cache.dir!" < $TESTDIR/fonts.conf.in > bind-fonts.conf
+$BWRAP --bind / / --bind $CACHEDIR $TESTTMPDIR/cache.dir --bind $FONTDIR $TESTTMPDIR/fonts --bind $TESTTMP2DIR $FONTDIR --bind .. $TESTTMPDIR/build --dev-bind /dev /dev --setenv FONTCONFIG_FILE $TESTTMPDIR/build/test/bind-fonts.conf $TESTTMPDIR/build/fc-match/fc-match$EXEEXT -f "%{file}\n" ":foundry=Misc" > xxx
+$BWRAP --bind / / --bind $CACHEDIR $TESTTMPDIR/cache.dir --bind $FONTDIR $TESTTMPDIR/fonts --bind $TESTTMP2DIR $FONTDIR --bind .. $TESTTMPDIR/build --dev-bind /dev /dev --setenv FONTCONFIG_FILE $TESTTMPDIR/build/test/bind-fonts.conf $TESTTMPDIR/build/test/test-bz106618$EXEEXT | sort > flist1
+$BWRAP --bind / / --bind $CACHEDIR $TESTTMPDIR/cache.dir --bind $FONTDIR $TESTTMPDIR/fonts --bind $TESTTMP2DIR $FONTDIR --bind .. $TESTTMPDIR/build --dev-bind /dev /dev find $TESTTMPDIR/fonts/ -type f -name '*.pcf' | sort > flist2
+ls -1 --color=no $CACHEDIR/*cache* > out2
+stat -c '%n %s %y %z' `cat out1` > stat2
+if cmp stat1 stat2 > /dev/null ; then : ; else
+  echo "*** Test failed: $TEST"
+  echo "cache was created/updated."
+  cat stat1 stat2
+  exit 1
+fi
+if grep -v -- "`cat out1`" out2 > /dev/null ; then : ; else
+  echo "*** Test failed: $TEST"
+  echo "cache wasn't created for dir inside sandbox."
+  cat out1 out2
+  exit 1
+fi
+if [ x`cat xxx` != "x$TESTTMPDIR/fonts/4x6.pcf" ]; then
+  echo "*** Test failed: $TEST"
+  echo "file property doesn't point to the new place: $TESTTMPDIR/fonts/4x6.pcf"
+  exit 1
+fi
+if cmp flist1 flist2 > /dev/null ; then
+  echo "*** Test failed: $TEST"
+  echo "Missing fonts should be available on sandbox"
+  echo "Expected result:"
+  cat flist2
+  echo "Actual result:"
+  cat flist1
+  exit 1
+fi
+rm -rf $TESTTMPDIR $TESTTMP2DIR out1 out2 xxx flist1 flist2 stat1 stat2 bind-fonts.conf
+
 fi
 
 if [ "x$EXEEXT" = "x" ]; then