scripts/populate: optimise search loop

Curently, populate will iterate over all ELF (shared objects|executables)
to look for missing NEEDED DSOs, adding to the list at every iterations
of the search loop.

Instead of looking again at previously handled ELF files, recursively
resolve every ELf files.

Also, in case there are a whole lot of files (more than the shell can
accept as arguments list, or creating a command line longer than the
shell can cope with), use a temporary file with the list of files
to search for missing dependencies.

scripts/populate.in

@@ -184,6 +184,12 @@ do_add_lib() {
     local dir
     local mode
 
+    for dir in lib usr/lib; do
+        if [ -e "${dir}/${libname}" ]; then
+            ${CT_PRINTF} "    already present\n"
+            return 0
+        fi
+    done
     for dir in lib usr/lib; do
         ${CT_PRINTF} "    trying in '%s'" "${dir}"
         libfile="${CT_SYSROOT_DIR}/${dir}/${libname}"
@@ -200,12 +206,36 @@ do_add_lib() {
             esac
             ${CT_PRINTF} "      installing as '%s/%s', mode='%s'\n" "${dir}" "${true_libname}" "${mode}"
             "${install}" -m "${mode}" "${libfile}" "${dir}/${true_libname}"
+            do_resolve_deps "${dir}/${true_libname}"
             return 0
         fi
     done
     return 1
 }
 
+# A function to resolve all NEEDED entries for the given file, relative
+# to the working directory (eg. dst_dir)
+# Usage: do_resolve_deps some/where/some/file
+# Returns: 0, meaning all dependencies were found
+# If not all dependencies could be found, exists with error code 1
+# (unless forced)
+do_resolve_deps() {
+    local file="${1}"
+    local libname
+    
+    for libname in $("${CT_READELF}" -d "${file}"                           \
+                     |"${grep}" -E '\(NEEDED\)[[:space:]]+Shared library:'  \
+                     |"${sed}" -r -e 's,.+\[(.+)\] *$,\1,;'                 \
+                    ); do
+        [ -n "${libname}" ] || continue
+        ${CT_PRINTF} "Searching for '%s' needed by '%s'\n" "${libname}" "${file}"
+        if ! do_add_lib "${libname}"; then
+            printf "$myname: library '${libname}' not found!\n"
+            [ "${CT_FORCE}" = "y" ] || exit 1
+        fi
+    done
+}
+
 # We'll work in the copied rootfs
 cd "${CT_ROOT_DST_DIR}"
 
@@ -223,12 +253,11 @@ CT_LIB_LIST=$(printf "${CT_LIB_LIST}:${lib_list}\n"         \
               |"${sed}" -r -e 's/^:+//; s/:+$//; s/:+/ /g;' \
              )
 if [ -n "${CT_LIB_LIST}" ]; then
-    ${CT_PRINTF} "Installing forced libraries...\n"
     for name in ${CT_LIB_LIST}; do
         [ -z "${name}" ] && continue
         found=0
         for libname in "lib${name}.so" "${name}.so" "${name}"; do
-            ${CT_PRINTF} "  searching for '%s'\n" "${libname}"
+            ${CT_PRINTF} "Searching for forced library '%s'\n" "${libname}"
             if do_add_lib "${libname}"; then
                 found=1
                 break
@@ -241,35 +270,28 @@ if [ -n "${CT_LIB_LIST}" ]; then
     done
 fi
 
-# Parse the working copy for executables and libraries
-still_needed=1
-while [ ${still_needed} -eq 1 ]; do
-    ${CT_PRINTF} "Looping...\n"
-    still_needed=0
-    for f in $(find . -type f -exec file {} \;                                              \
-               |"${grep}" -E ': ELF [[:digit:]]+-bit (L|M)SB (executable|shared object),'   \
-               |cut -d ":" -f 1                                                             \
-              ); do
-        ${CT_PRINTF} "Scanning '%s'\n" "${f}"
-        for libname in $("${CT_READELF}" -d "${f}"                              \
-                         |"${grep}" -E '\(NEEDED\)[[:space:]]+Shared library:'  \
-                         |"${sed}" -r -e 's,.+\[(.+)\] *$,\1,;'                 \
-                        ); do
-            ${CT_PRINTF} "  searching for '%s'\n" "${libname}"
-            if [    -e "lib/${libname}"     \
-                 -o -e "usr/lib/${libname}" ]; then
-                ${CT_PRINTF} "    already present\n"
-                continue
-            fi
-            if do_add_lib "${libname}"; then
-                still_needed=1
-            else
-                printf "$myname: library '${libname}' not found!\n"
-                [ "${CT_FORCE}" = "y" ] || exit 1
-            fi
-        done
-    done
-done
+# Create a temporary place where to store... temp files.
+rand="$( dd if=/dev/urandom bs=1024 count=1 2>/dev/null \
+         |md5sum                                        \
+         |awk '{ print $1; }'
+       )"
+CT_TMP_DIR="${TMPDIR:-/tmp}/populate-${rand}-${$}"
+( umask 0077; mkdir "${CT_TMP_DIR}" ) || { printf "Could not create temporary directory\n"; exit 1; }
+trap "rm -rf ${CT_TMP_DIR}" EXIT
+
+# List all ELF (executables|shared objects)...
+find . -type f -exec file {} \;                                             \
+|"${grep}" -E ': ELF [[:digit:]]+-bit (L|M)SB (executable|shared object),'  \
+|cut -d ":" -f 1                                                            \
+>"${CT_TMP_DIR}/files.list"
+
+# ... and use that list to find missing dependencies
+while read file; do
+    do_resolve_deps "${file}"
+done <"${CT_TMP_DIR}/files.list"
+
+rm -rf "${CT_TMP_DIR}"
+trap - EXIT
 
 # OK, we're done. Back off.
 cd - >/dev/null