build: fix invocation of bundled ld.so in SDK and Imagebuilder

[openwrt/openwrt.git] / scripts / bundle-libraries.sh

diff --git a/scripts/bundle-libraries.sh b/scripts/bundle-libraries.sh
index dfc2b85a47a922f6544e0c95206b0b15260a4ba7..b108fd8f7768a34205ae1529548bec08d9c978c1 100755 (executable)
--- a/scripts/bundle-libraries.sh
+++ b/scripts/bundle-libraries.sh
@@ -70,26 +70,27 @@ _relpath() {
        done
 }
 
-_wrapper() {
-       cat <<-EOT | ${CC:-gcc} -x c -o "$1" -
+_runas_so() {
+       cat <<-EOT | ${CC:-gcc} -x c -fPIC -shared -o "$1" -
                #include <unistd.h>
                #include <stdio.h>
+               #include <stdlib.h>
 
-               int main(int argc, char **argv) {
-                       const char *self   = argv[0];
-                       const char *target = argv[1];
+               int mangle_arg0(int argc, char **argv, char **env) {
+                       char *arg0 = getenv("RUNAS_ARG0");
 
-                       if (argc < 3) {
-                               fprintf(stderr, "Usage: %s executable arg0 [args...]\n", self);
-                               return 1;
-                       }
+                       if (arg0)
+                               argv[0] = arg0;
 
-                       return execv(target, argv + 2);
+                       return 0;
                }
+
+               __attribute__((section(".init_array")))
+               static void *mangle_arg0_constructor = &mangle_arg0;
        EOT
 
        [ -x "$1" ] || {
-               echo "compiling wrapper failed" >&2
+               echo "compiling preload library failed" >&2
                exit 5
        }
 }
@@ -113,13 +114,13 @@ for BIN in "$@"; do
                _ln "../lib" "$DIR/usr/lib"
        }
 
-       [ ! -x "$DIR/lib/runas" ] && {
-               _wrapper "$DIR/lib/runas"
+       [ ! -x "$DIR/lib/runas.so" ] && {
+               _runas_so "$DIR/lib/runas.so"
        }
 
        LDSO=""
 
-       [ -n "$LDD" ] && [ -x "$BIN" ] && file "$BIN" | grep -sqE "ELF.*executable" && {
+       [ -n "$LDD" ] && [ -x "$BIN" ] && file "$BIN" | grep -sqE "ELF.*(executable|interpreter)" && {
                for token in $("$LDD" "$BIN" 2>/dev/null); do
                        case "$token" in */*.so*)
                                case "$token" in
@@ -150,7 +151,9 @@ for BIN in "$@"; do
                cat <<-EOF > "$BIN"
                        #!/usr/bin/env bash
                        dir="\$(dirname "\$0")"
-                       exec "\$dir/${REL:+$REL/}$LDSO" --library-path "\$dir/${REL:+$REL/}" "\$dir/${REL:+$REL/}runas" "\$dir/.${BIN##*/}.bin" "\$0" "\$@"
+                       export RUNAS_ARG0="\$0"
+                       export LD_PRELOAD="\$dir/${REL:+$REL/}runas.so"
+                       exec "\$dir/${REL:+$REL/}$LDSO" --library-path "\$dir/${REL:+$REL/}" "\$dir/.${BIN##*/}.bin" "\$@"
                EOF
 
                chmod ${VERBOSE:+-v} 0755 "$BIN"