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authorPatrick 'P. J.' McDermott <pj@pehjota.net>2013-09-11 23:13:36 -0400
committerMike Frysinger <vapier@gentoo.org>2013-10-14 01:57:46 -0400
commit94bf958a9435b8d8fbf92c15d8cd5d310029a22c (patch)
tree5b7d470cf9375acd4f7d1e5ee1711a65f9ac64e2 /elf
parent0abe1dd5368a91601dabcda484ecd873a5789497 (diff)
downloadglibc-94bf958a9435b8d8fbf92c15d8cd5d310029a22c.tar.gz
ldd: make try_trace more robust and portable
It was noted in 2005 (BZ #832), 2006 (BZ #3266), and 2007 [1] that ldd fails on shells other than Bash >= 3.0 because of the pipefail option around try_trace (added on 2004-12-08). EGLIBC was patched in 2008 [2] (r6912) to make the pipefail check run only on shells that support it, but RTLD output would still be lost on other shells with certain SELinux policies. This patch rewrites try_trace to work on any POSIX-conformant shell in such a way as to also work with such SELinux policies. It also obviates one difference between glibc and EGLIBC. URL: https://sourceware.org/ml/libc-alpha/2007-01/msg00041.html URL: http://www.eglibc.org/archives/patches/msg00526.html 2013-09-11 P. J. McDermott <pj@pehjota.net> [BZ #832] * elf/ldd.bash.in (try_trace): More robustly and portably work around SELinux terminal write permissions by using a command substitution instead of a pipeline and pipefail option.
Diffstat (limited to 'elf')
-rw-r--r--elf/ldd.bash.in25
1 files changed, 12 insertions, 13 deletions
diff --git a/elf/ldd.bash.in b/elf/ldd.bash.in
index 39aeca249d..c4a1a15139 100644
--- a/elf/ldd.bash.in
+++ b/elf/ldd.bash.in
@@ -106,19 +106,18 @@ if test "$unused" = yes; then
add_env="$add_env LD_DEBUG=\"$LD_DEBUG${LD_DEBUG:+,}unused\""
fi
-# The following use of cat is needed to make ldd work in SELinux
-# environments where the executed program might not have permissions
-# to write to the console/tty. But only bash 3.x supports the pipefail
-# option, and we don't bother to handle the case for older bash versions.
-if set -o pipefail 2> /dev/null; then
- try_trace() {
- eval $add_env '"$@"' | cat
- }
-else
- try_trace() {
- eval $add_env '"$@"'
- }
-fi
+# The following command substitution is needed to make ldd work in SELinux
+# environments where the RTLD might not have permission to write to the
+# terminal. The extra "x" character prevents the shell from trimming trailing
+# newlines from command substitution results. This function is defined as a
+# subshell compound list (using "(...)") to prevent parameter assignments from
+# affecting the calling shell execution environment.
+try_trace() (
+ output=$(eval $add_env '"$@"' 2>&1; rc=$?; printf 'x'; exit $rc)
+ rc=$?
+ printf '%s' "${output%x}"
+ return $rc
+)
case $# in
0)