Remove escaping of backslashes to support literal ${var}

src/cfgprint.c

@@ -70,12 +70,15 @@ static void fwup_cfg_opt_nprint_var(cfg_opt_t *opt, unsigned int index, struct s
     case CFGT_STR:
     {
         const char *str = cfg_opt_getnstr(opt, index);
+        // Fwup's feature of re-evaluating strings when applying firmware
+        // updates is a feature and used to modify behavior when applying
+        // firmware updates (aka runtime). Fwup has always escaped double
+        // quotes, though, since it really messes up error messages when
+        // double quotes aren't escaped.
         ssprintf(s, "\"");
         while (str && *str) {
             if (*str == '"')
                 ssprintf(s, "\\\"");
-            else if (*str == '\\')
-                ssprintf(s, "\\\\");
             else
                 ssprintf(s, "%c", *str);
             str++;

tests/004_env_vars.test

@@ -16,6 +16,12 @@ cat >"$CONFIG" <<EOF
 # Test substitution in a field
 meta-product = \${TEST_ENV_VAR}
 
+# Test substitution in double quotes
+meta-author = "\${TEST_ENV_VAR}"
+
+# Test no substitution in single quotes
+meta-misc = '\${TEST_ENV_VAR}'
+
 # Test substitution in a resource name
 file-resource "\${TEST_ENV_VAR}" {
         # Test substitution in the middle of a string
@@ -30,6 +36,8 @@ EOF
 
 cat >"$EXPECTED_META_CONF" <<EOF
 meta-product="${TEST_ENV_VAR}"
+meta-author="${TEST_ENV_VAR}"
+meta-misc="\${TEST_ENV_VAR}"
 file-resource "${TEST_ENV_VAR}" {
   length=1024
   blake2b-256="b25c2dfe31707f5572d9a3670d0dcfe5d59ccb010e6aba3b81aad133eb5e378b"

tests/135_execute.test

@@ -14,7 +14,10 @@ EXE_CMD="dd if=${LOCAL_FILE} of=${OUTFILE}"
 
 if [ "$CC" = "x86_64-w64-mingw32-gcc" -o "$MODE" = "windows" ]; then
     # dd usually isn't available on Windows
-    EXE_CMD="copy work-135_execute.test\\\\somefile.txt work-135_execute.test\\\\output.txt"
+    #
+    # 8 backslashes to get 1 backslash since the string gets evaluated 3 times:
+    # shell script, fwup create, fwup apply. :(
+    EXE_CMD="copy work-135_execute.test\\\\\\\\somefile.txt work-135_execute.test\\\\\\\\output.txt"
 fi
 
 cat >$LOCAL_FILE <<EOF

tests/201_string_handling.test

@@ -0,0 +1,45 @@
+#!/bin/sh
+
+#
+# Test environment variables embedded in strings in the config files
+#
+# If this fails, you're using an old version of libconfuse. This is sadly
+# very common. See the readme, but the basic fix is to go to the libconfuse
+# GitHub and build it yourself.
+#
+
+. "$(cd "$(dirname "$0")" && pwd)/common.sh"
+
+export TEST_ENV_VAR=1K.bin
+
+cat >$CONFIG <<EOF
+# Escape sequence in double quotes
+meta-product = "Octal \044 and hex \x3c"
+# Backslashes are escaped
+meta-description = "\\\\$"
+# Escape sequences and variables dont get processed in single quotes
+meta-version = '\044 \x3c \${}'
+# Substitution happens in double quotes
+meta-author = "Substitution \${}"
+# Escapes quotes in double quotes (fwup weird behavior 1)
+meta-platform = "\"\""
+# Escapes quotes in single quotes (fwup weird behavior 2)
+meta-architecture = '""'
+EOF
+
+cat >$EXPECTED_META_CONF <<EOF
+meta-product="Octal $ and hex <"
+meta-description="\\$"
+meta-version="\044 \x3c \${}"
+meta-author="Substitution"
+meta-platform="\"\""
+meta-architecture="\"\""
+EOF
+
+$FWUP_CREATE -c -f $CONFIG -o $FWFILE
+
+# Check that the zip file was created as expected
+check_meta_conf
+
+# Check that the verify logic works on this file
+$FWUP_VERIFY -V -i $FWFILE

tests/Makefile.am

@@ -200,6 +200,7 @@ TESTS = 001_simple_fw.test \
 	197_fractional_end_segment.test \
 	198_gpt_partial.test \
 	199_partial_read.test \
-	200_uboot_redundant_255.test
+	200_uboot_redundant_255.test \
+	201_string_handling.test
 
 EXTRA_DIST = $(TESTS) common.sh 1K.bin 1K-corrupt.bin 150K.bin