Allow string arguments to be read from files.

If a string argument to an option is prefixed with @, then a file with the
following name will be read into that string.

4 files changed, 53 insertions, 10 deletions

diff --git a/patchelf.1 b/patchelf.1
index 1016f69..d6ab167 100644
--- a/patchelf.1
+++ b/patchelf.1
@@ -23,6 +23,9 @@ of executables and change the RPATH of executables and libraries.
 
 The single option given operates on each FILE, editing in place.
 
+Any option taking a string argument can also take a file by prefixing the
+argument with the @ symbol. See EXAMPLES
+
 .IP "--page-size SIZE"
 Uses the given page size instead of the default.
 
@@ -72,11 +75,11 @@ DT_RUNPATH. By default DT_RPATH is converted to DT_RUNPATH.
 
 .IP "--add-needed LIBRARY"
 Adds a declared dependency on a dynamic library (DT_NEEDED).
-This option can be give multiple times.
+This option can be given multiple times.
 
 .IP "--replace-needed LIB_ORIG LIB_NEW"
 Replaces a declared dependency on a dynamic library with another one (DT_NEEDED).
-This option can be give multiple times.
+This option can be given multiple times.
 
 .IP "--remove-needed LIBRARY"
 Removes a declared dependency on LIBRARY (DT_NEEDED entry). This
@@ -95,6 +98,23 @@ Prints details of the changes made to the input file.
 .IP --version
 Shows the version of patchelf.
 
+.SH EXAMPLES
+
+To use the contents on an external file as a parameter:
+
+.RS
+$ patchelf a.out --add-rpath @/tmp/generated-rpath.bin
+.RE
+
+To change the RPATH of a binary. Note that
+.BR $ORIGIN
+is a special symbol used by the loader, so must be quoted.
+
+.RS
+patchelf --set-rpath '$ORIGIN/../lib64' a.out
+.RE
+
+
 .SH AUTHOR
 Eelco Dolstra <e.dolstra@tudelft.nl>
 
diff --git a/src/patchelf.cc b/src/patchelf.cc
index 3ca16c7..9518d4f 100644
--- a/src/patchelf.cc
+++ b/src/patchelf.cc
@@ -1870,6 +1870,15 @@ static void patchElf()
     }
 }
 
+std::string resolveArgument(const char *arg) {
+  if (strlen(arg) > 0 && arg[0] == '@') {
+    FileContents cnts = readFile(arg + 1);
+    return std::string((char *)cnts->data(), cnts->size());
+  }
+
+  return std::string(arg);
+}
+
 
 void showHelp(const std::string & progName)
 {
@@ -1914,7 +1923,7 @@ int mainWrapped(int argc, char * * argv)
         std::string arg(argv[i]);
         if (arg == "--set-interpreter" || arg == "--interpreter") {
             if (++i == argc) error("missing argument");
-            newInterpreter = argv[i];
+            newInterpreter = resolveArgument(argv[i]);
         }
         else if (arg == "--page-size") {
             if (++i == argc) error("missing argument");
@@ -1930,7 +1939,7 @@ int mainWrapped(int argc, char * * argv)
         else if (arg == "--set-soname") {
             if (++i == argc) error("missing argument");
             setSoname = true;
-            newSoname = argv[i];
+            newSoname = resolveArgument(argv[i]);
         }
         else if (arg == "--remove-rpath") {
             removeRPath = true;
@@ -1945,12 +1954,12 @@ int mainWrapped(int argc, char * * argv)
         else if (arg == "--set-rpath") {
             if (++i == argc) error("missing argument");
             setRPath = true;
-            newRPath = argv[i];
+            newRPath = resolveArgument(argv[i]);
         }
         else if (arg == "--add-rpath") {
             if (++i == argc) error("missing argument");
             addRPath = true;
-            newRPath = argv[i];
+            newRPath = resolveArgument(argv[i]);
         }
         else if (arg == "--print-rpath") {
             printRPath = true;
@@ -1974,11 +1983,11 @@ int mainWrapped(int argc, char * * argv)
         }
         else if (arg == "--add-needed") {
             if (++i == argc) error("missing argument");
-            neededLibsToAdd.insert(argv[i]);
+            neededLibsToAdd.insert(resolveArgument(argv[i]));
         }
         else if (arg == "--remove-needed") {
             if (++i == argc) error("missing argument");
-            neededLibsToRemove.insert(argv[i]);
+            neededLibsToRemove.insert(resolveArgument(argv[i]));
         }
         else if (arg == "--replace-needed") {
             if (i+2 >= argc) error("missing argument(s)");
@@ -1987,11 +1996,11 @@ int mainWrapped(int argc, char * * argv)
         }
         else if (arg == "--clear-symbol-version") {
             if (++i == argc) error("missing argument");
-            symbolsToClearVersion.insert(argv[i]);
+            symbolsToClearVersion.insert(resolveArgument(argv[i]));
         }
         else if (arg == "--output") {
             if (++i == argc) error("missing argument");
-            outputFileName = argv[i];
+            outputFileName = resolveArgument(argv[i]);
             alwaysWrite = true;
         }
         else if (arg == "--debug") {
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 46589ea..0622dbf 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -36,6 +36,7 @@ src_TESTS = \
   contiguous-note-sections.sh \
   no-gnu-hash.sh \
   no-dynamic-section.sh \
+  external.sh \
   basic-flags.sh
 
 build_TESTS = \
diff --git a/tests/external.sh b/tests/external.sh
new file mode 100755
index 0000000..0123692
--- /dev/null
+++ b/tests/external.sh
@@ -0,0 +1,13 @@
+#! /bin/sh -e
+SCRATCH=scratch/$(basename $0 .sh)
+
+rm -rf ${SCRATCH}
+mkdir -p ${SCRATCH}
+
+cp main ${SCRATCH}/
+RANDOM_PATH=$(pwd)/${SCRATCH}/$RANDOM
+echo -n ${RANDOM_PATH} >> ${SCRATCH}/add-rpath
+
+! ../src/patchelf --print-rpath ${SCRATCH}/main | grep $RANDOM_PATH
+../src/patchelf --add-rpath @${SCRATCH}/add-rpath ${SCRATCH}/main
+../src/patchelf --print-rpath ${SCRATCH}/main | grep $RANDOM_PATH