[shellprocess] Migrate towards 'standard' variable substitutions

src/modules/shellprocess/Tests.cpp

@@ -146,14 +146,14 @@ script:
     QVariant plainScript = CalamaresUtils::yamlMapToVariant( doc ).value( "script" );
     QVariant rootScript = CalamaresUtils::yamlMapToVariant( YAML::Load( R"(---
 script:
-    - "ls @@ROOT@@"
+    - "ls ${ROOT}"
 )" ) )
                               .value( "script" );
     QVariant userScript = CalamaresUtils::yamlMapToVariant( YAML::Load( R"(---
 script:
-    - mktemp -d @@ROOT@@/calatestXXXXXXXX
-    - "chown @@USER@@ @@ROOT@@/calatest*"
-    - rm -rf @@ROOT@@/calatest*
+    - mktemp -d ${ROOT}/calatestXXXXXXXX
+    - "chown ${USER} ${ROOT}/calatest*"
+    - rm -rf ${ROOT}/calatest*
 )" ) )
                               .value( "script" );
 
@@ -167,13 +167,13 @@ script:
 
     qDebug() << "Expect WARNING, ERROR, WARNING";
 
-    // Doesn't use @@ROOT@@, so no failures
+    // Doesn't use ${ROOT}, so no failures
     QVERIFY( bool( CommandList( plainScript, false, 10s ).run() ) );
 
-    // Doesn't use @@ROOT@@, but does chroot, so fails
+    // Doesn't use ${ROOT}, but does chroot, so fails
     QVERIFY( !bool( CommandList( plainScript, true, 10s ).run() ) );
 
-    // Does use @@ROOT@@, which is not set, so fails
+    // Does use ${ROOT}, which is not set, so fails
     QVERIFY( !bool( CommandList( rootScript, false, 10s ).run() ) );
     // .. fails for two reasons
     QVERIFY( !bool( CommandList( rootScript, true, 10s ).run() ) );

src/modules/shellprocess/Tests.h

@@ -31,7 +31,7 @@ private Q_SLOTS:
     void testProcessFromObject();
     // Create from a complex YAML list
     void testProcessListFromObject();
-    // Check @@ROOT@@ substitution
+    // Check variable substitution
     void testRootSubstitution();
 };
 

src/modules/shellprocess/shellprocess.conf

@@ -7,11 +7,13 @@
 # If the top-level key *dontChroot* is true, then the commands
 # are executed in the context of the live system, otherwise
 # in the context of the target system. In all of the commands,
-# the following substitutions will take place:
-#  - `@@ROOT@@` is replaced by the root mount point of the **target**
-#    system from the point of view of the command (for chrooted
-#    commands, that will be */*).
-#  - `@@USER@@` is replaced by the username, set on the user page.
+# the following variable expansions will take place:
+#  - `ROOT` is replaced by the root mount point of the **target**
+#    system from the point of view of the command (when run in the target
+#    system, e.g. when *dontChroot* is false, that will be `/`).
+#  - `USER` is replaced by the username, set on the user page.
+#
+# Variables are written as `${var}`, e.g. `${ROOT}`.
 #
 # The (global) timeout for the command list can be set with
 # the *timeout* key. The value is a time in seconds, default
@@ -72,7 +74,7 @@ dontChroot: false
 # ignored; the slowloris command has a different timeout from the
 # other commands in the list):
 script:
-    - "-touch @@ROOT@@/tmp/thingy"
+    - "-touch ${ROOT}/tmp/thingy"
     - "/usr/bin/true"
     - command: "/usr/local/bin/slowloris"
       timeout: 3600