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authorElliott Hughes <enh@google.com>2019-02-12 16:29:09 -0800
committerRob Landley <rob@landley.net>2019-02-12 21:31:20 -0600
commit7079a558d6e9448d5434965985b650c1e572140e (patch)
tree5421ca8fe368722a744a7a5c906b05a6a5780c55
parent8326fe1f7e141f49a46a57acc6221651298b42c9 (diff)
downloadtoybox-7079a558d6e9448d5434965985b650c1e572140e.tar.gz
sed: fix substitution of empty capturing groups.
The test for \N where N was larger than the number of capturing groups in the regular expression was incorrect, and firing for cases such as matching __(ARM_)?NR_([a-z]*) against __NR_read, where the first group is empty (because it failed to match) but the second group did match "read". Use regex_t's re_nsub for the error check, and treat rm_so == -1 as a signal to just copy nothing into the result. (Found trying to build minijail in AOSP.)
-rwxr-xr-xtests/sed.test11
-rw-r--r--toys/posix/sed.c9
2 files changed, 17 insertions, 3 deletions
diff --git a/tests/sed.test b/tests/sed.test
index f2ff8fd7..34dfa161 100755
--- a/tests/sed.test
+++ b/tests/sed.test
@@ -72,6 +72,8 @@ testing "aci" \
"sed -e '3a boom' -e '/hre/i bang' -e '3a whack' -e '3c bong'" \
"one\ntwo\nbang\nbong\nboom\nwhack\nfour\n" "" \
"one\ntwo\nthree\nfour\n"
+# TODO: next test is broken on new-ish debian/bash with never-ending
+# output of `sed: short write: Broken pipe`.
testing "b loop" "sed ':woo;=;b woo' | head -n 5" '1\n1\n1\n1\n1\n' "" "X"
testing "b skip" "sed -n '2b zap;d;:zap;p'" "two\n" "" "one\ntwo\nthree"
testing "b end" "sed -n '2b;p'" "one\nthree" "" "one\ntwo\nthree"
@@ -167,4 +169,13 @@ testing "end b with }" "sed -n '/START/{:a;n;/END/q;p;ba}'" "b\nc\n" \
testing '-z' 'sed -z "s/\n/-/g"' "a-b-c" "" "a\nb\nc"
+# toybox handling of empty capturing groups broke minjail. Check that we
+# correctly replace an empty capturing group with the empty string:
+testing '\n with empty capture' \
+ 'sed -E "s/(ARM_)?(NR_)([a-z]*) (.*)/\1\2\3/"' "NR_read" "" "NR_read foo"
+# ...but also that we report an error for a backreference to a group that
+# isn't in the pattern:
+testing '\n too high' \
+ 'sed -E "s/(.*)/\2/p" 2>/dev/null || echo OK' "OK\n" "" "foo"
+
# -i with $ last line test
diff --git a/toys/posix/sed.c b/toys/posix/sed.c
index 228055f9..0be2165e 100644
--- a/toys/posix/sed.c
+++ b/toys/posix/sed.c
@@ -528,15 +528,18 @@ static void sed_line(char **pline, long plen)
rswap[mlen-1] = new[off];
continue;
- } else if (match[cc].rm_so == -1) error_exit("no s//\\%d/", cc);
+ } else if (cc > reg->re_nsub) error_exit("no s//\\%d/", cc);
} else if (new[off] != '&') {
rswap[mlen++] = new[off];
continue;
}
- ll = match[cc].rm_eo-match[cc].rm_so;
- memcpy(rswap+mlen, rline+match[cc].rm_so, ll);
+ if (match[cc].rm_so == -1) ll = 0; // Empty match.
+ else {
+ ll = match[cc].rm_eo-match[cc].rm_so;
+ memcpy(rswap+mlen, rline+match[cc].rm_so, ll);
+ }
mlen += ll;
}