ash: expand: Fix trailing newlines processing in backquote expanding

Upstream commit:

    Date: Mon, 29 Apr 2019 19:13:37 +0500
    expand: Fix trailing newlines processing in backquote expanding

    According to POSIX.1-2008 we should remove newlines only at the end of
    the substitution. Newlines-only substitions causes dash to remove
    newlines before beggining of the substitution. The following code:

        cat <<END
        1
        $(echo "")
        2
        END

    prints "1<newline>2" instead of expected "1<newline><newline>2".

    This patch fixes trailing newlines processing in backquote expanding.

    Signed-off-by: Nikolai Merinov <n.merinov@inango-systems.com>
    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2020-02-17 10:24:32 +01:00
parent c2ce888030
commit 9ee5892798
5 changed files with 25 additions and 1 deletions

View File

@ -6578,7 +6578,7 @@ expbackq(union node *cmd, int flag)
/* Eat all trailing newlines */
dest = expdest;
for (; dest > (char *)stackblock() && dest[-1] == '\n';)
for (; dest > ((char *)stackblock() + startloc) && dest[-1] == '\n';)
STUNPUTC(dest);
expdest = dest;

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@ -0,0 +1,5 @@
1
2
3

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@ -0,0 +1,7 @@
cat <<END
1
$(echo "")
2
`echo ""`
3
END

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@ -0,0 +1,5 @@
1
2
3

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@ -0,0 +1,7 @@
cat <<END
1
$(echo "")
2
`echo ""`
3
END