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Diffstat (limited to 'contrib/bmake/unit-tests/varmod-loop-delete.mk')
| -rw-r--r-- | contrib/bmake/unit-tests/varmod-loop-delete.mk | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/contrib/bmake/unit-tests/varmod-loop-delete.mk b/contrib/bmake/unit-tests/varmod-loop-delete.mk new file mode 100644 index 000000000000..1ec6d361949d --- /dev/null +++ b/contrib/bmake/unit-tests/varmod-loop-delete.mk @@ -0,0 +1,34 @@ +# $NetBSD: varmod-loop-delete.mk,v 1.3 2023/06/01 20:56:35 rillig Exp $ +# +# Tests for the variable modifier ':@', which as a side effect allows to +# delete an arbitrary variable. + +# A side effect of the modifier ':@' is that the loop variable is created as +# an actual variable in the current evaluation scope (Command/Global/target), +# and at the end of the loop, this variable is deleted. Since var.c 1.204 +# from 2016-02-18 and before var.c 1.963 from 2021-12-05, a variable could be +# deleted while it was in use, leading to a use-after-free bug. +# +# See Var_Parse, comment 'the value of the variable must not change'. + +# Set up the variable that deletes itself when it is evaluated. +VAR= ${:U:@VAR@@} rest of the value + +# In an assignment, the scope is 'Global'. Since the variable 'VAR' is +# defined in the global scope, it deletes itself. +# expect+1: Cannot delete variable "VAR" while it is used +EVAL:= ${VAR} +.if ${EVAL} != " rest of the value" +. error +.endif + +VAR= ${:U:@VAR@@} rest of the value +all: .PHONY + # In the command that is associated with a target, the scope is the + # one from the target. That scope only contains a few variables like + # '.TARGET', '.ALLSRC', '.IMPSRC'. Make does not expect that these + # variables get modified from the outside. + # + # There is no variable named 'VAR' in the local scope, so nothing + # happens. + : $@: '${VAR}' |