hang_processes.sh: Obtain list of loaded dynamic objects using strings

While this is quite ugly, it has the advantage that we get the path to
the object files actually loaded by the application.  So if it loaded
some particular shared object due due to some LD_LIBRARY_PATH value or
because it dlopen'ed them, we will catch them.

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>

diff --git a/scripts/lttng-tools/hang_processes.sh b/scripts/lttng-tools/hang_processes.sh
index 09672182b06f7012fff598c180a9b13b7103d205..f0d2ccf7cac09bd2c129bc5cf1ee5c39f54fa832 100755 (executable)
--- a/scripts/lttng-tools/hang_processes.sh
+++ b/scripts/lttng-tools/hang_processes.sh
@@ -17,7 +17,6 @@
 
 PGREP=pgrep
 pids=""
-dependencies=""
 file_list=$(mktemp)
 ret=0
 
@@ -34,39 +33,50 @@ if [ -n "$lttng_processes" ]; then
 
     # Stop the processes to make sure everything is frozen
     kill -SIGSTOP $pids
-
-    # Get dependencies for coredump analysis
-    # Use /proc/$PID/exe and ldd to get all shared libs necessary
-    array=(${pids})
-    # Add the /proc/ prefix using parameter expansion
-    array=("${array[@]/#/\/proc\/}")
-    # Add the /exe suffix using parameter expansion
-    array=("${array[@]/%/\/exe}")
-    dependencies=$(ldd "${array[@]}" | grep -v "not found")
-    dependencies=$(awk '/=>/{print$(NF-1)}' <<< "$dependencies" | sort | uniq)
-
     kill -SIGABRT $pids
     kill -SIGCONT $pids
     ret=1
 fi
 
-core_files=$(find "/tmp" -name "core\.[0-9]*" -type f 2>/dev/null) || true
-if [ -n "$core_files" ]; then
-    echo "$core_files" >> "$file_list"
-    echo "$dependencies" >> "$file_list"
+# Add the file passed as $1 to the list of files to collect.
+#
+# If that file is a symlink, follow it and collect the target, recursively.
+
+function collect_recursive
+{
+    file_to_collect=$1
+
+    if [ -f "$file_to_collect" ]; then
+        echo "$file_to_collect" >> "$file_list"
+
+        if [ -L "$file_to_collect" ]; then
+            collect_recursive "$(readlink "$file_to_collect")"
+        fi
+    fi
+}
 
-    # Make sure the coredump is finished using fuser
-    for core in $core_files; do
-        while fuser "$core"; do
-            sleep 1
-        done
+# For each core file...
+while read -r core_file; do
+    # Make sure the coredump is finished using fuser.
+    while fuser "$core_file"; do
+        sleep 1
     done
 
-    mkdir -p "${WORKSPACE}/build"
-    tar cfzh "${WORKSPACE}/build/core.tar.gz" -T "$file_list"
-    rm -f "$core_files"
+    # Collect everything in the core file that looks like a reference to a
+    # shared lib.
+    strings "$core_file" | grep '^/.*\.so.*' | while read -r str; do
+        collect_recursive "$str"
+    done
+
+    rm -f "$core_file"
     ret=1
+done < <(find "/tmp" -maxdepth 1 -name "core\.[0-9]*" -type f 2>/dev/null)
+
+# If we recorded some files to collect, pack them up.
+if [ -s "$file_list" ]; then
+    mkdir -p "${WORKSPACE}/build"
+    tar cfzh "${WORKSPACE}/build/core.tar.gz" -T <(sort "$file_list" | uniq)
 fi
 
-rm -rf "$file_list"
+rm -f "$file_list"
 exit $ret