Feature: CLI options for bundle directory and program name

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "editor.formatOnSave": false
+}

bootloader/common.h

@@ -5,6 +5,7 @@
 #define ARCHIVE_SECTION         ".staticx.archive"
 #define INTERP_FILENAME         ".staticx.interp"
 #define PROG_FILENAME           ".staticx.prog"
+#define BUNDLE_DIR_FILENAME     ".staticx.bundle-dir"
 
 static inline void *
 ptr_add(void *p, size_t off)

bootloader/main.c

@@ -11,6 +11,7 @@
 #include <fcntl.h>
 #include <elf.h>
 #include <sys/wait.h>
+#include <sys/param.h>
 #include "xz.h"
 #include "error.h"
 #include "mmap.h"
@@ -31,7 +32,7 @@
 
 
 /* The "bundle" directory, where the archive is extracted */
-static const char *m_bundle_dir;
+static char *m_bundle_dir;
 
 static char *
 path_join(const char *p1, const char *p2)
@@ -382,30 +383,58 @@ cleanup_bundle_dir(void)
         fprintf(stderr, "staticx: Failed to cleanup %s: %m\n", m_bundle_dir);
     }
 
-    free((void*)m_bundle_dir);
+    free(m_bundle_dir);
     m_bundle_dir = NULL;
 }
 
 /**
- * Returns the path to the actual user program to execute.
- * We resolve this manually rather than executing the symlink
- * to ensure the program sees the original argv[0]. See #134.
- *
- * Note however that we do not currently pass-through argv[0].
- * See #133.
+ * Returns the path stored in the specified symlink file.
+ * 
+ * We resolve this manually rather than executing the symlink for the program to ensure that the program sees the original argv[0] (see #134). Note however that we do not currently pass-through argv[0] (see #133).
  */
-static char *
-get_real_prog_path(void)
+static char *get_symlink(char *file_path)
 {
-    // PROG_FILENAME is a symlink to the user's program
-    char *linkpath = path_join(m_bundle_dir, PROG_FILENAME);
+    char *absolute_path = path_join(m_bundle_dir, file_path);
 
-    char *result = realpath(linkpath, NULL);
-    if (!result)
-        error(2, errno, "Failed to get realpath for %s", linkpath);
+    char *linked_path = malloc(MAXPATHLEN + 1);
+    ssize_t path_length = readlink(absolute_path, linked_path, MAXPATHLEN);
 
-    free(linkpath);
-    return result;
+    if (path_length == -1)
+        error(2, errno, "Failed to read the symlink for %s", absolute_path);
+    if (path_length > MAXPATHLEN)
+        error(2, errno, "Length of symlink value (%zu) for %s is too long", path_length, absolute_path);
+
+    free(absolute_path);
+    linked_path[path_length] = '\0';
+    return linked_path;
+}
+
+/**
+ * Moves and renames the bundle from `m_bundle_dir` to the `destination` and updates `m_bundle_dir` (do not free `destination`). Fails when a file or folder already exists at the `destination`.
+ */
+inline static void move_bundle(char *destination)
+{
+    char *origin = m_bundle_dir;
+    if (access(destination, F_OK) == 0)
+        error(2, 0, "Failed to move bundle from %s to %s because the destination already exists", origin, destination);
+
+    int result = rename(origin, destination);
+    if (result == -1)
+        error(2, errno, "Failed to move the bundle from %s to %s", origin, destination);
+
+    free(origin);
+    m_bundle_dir = destination;
+}
+
+/**
+ * Checks whether or not a file exists within the bundle. Does not follow symlinks.
+ */
+static bool file_exists(char *file_path)
+{
+    char *absolute_path = path_join(m_bundle_dir, file_path);
+    bool exists = faccessat(0, absolute_path, F_OK, AT_SYMLINK_NOFOLLOW) == 0;
+    free(absolute_path);
+    return exists;
 }
 
 static void identify(void)
@@ -432,8 +461,17 @@ main(int argc, char **argv)
     /* Extract the archive embedded in this program */
     extract_archive(m_bundle_dir);
 
+    /* Check for custom bundle directory and move the bundle */
+    if (file_exists(BUNDLE_DIR_FILENAME)) {
+        move_bundle(get_symlink(BUNDLE_DIR_FILENAME));
+        debug_printf("Moved the bundle dir to: %s\n", m_bundle_dir);
+    }
+
     /* Get path to user application inside temp dir */
-    char *prog_path = get_real_prog_path();
+    char *prog_name = get_symlink(PROG_FILENAME);
+    char *prog_path = path_join(m_bundle_dir, prog_name);
+    debug_printf("Program located at: %s\n", prog_path);
+    free(prog_name);
 
     /* Patch the user application ELF to run in the temp dir */
     patch_app(prog_path);

docs/usage.rst

@@ -3,11 +3,12 @@ Usage
 
 Synopsis
 --------
-.. code-block::
+.. code-block:: shell
 
    staticx [-h]
-           [-l LIB] [--strip] [--no-compress] [-V]
-           [--loglevel LEVEL]
+           [-l LIB] [--strip] [--no-compress]
+           [--bundle-dir BUNDLE_DIR] [--prog-name PROG_NAME]
+           [-V] [--loglevel LEVEL]
            PROG OUTPUT
 
 Positional Arguments:
@@ -19,12 +20,17 @@ Positional Arguments:
 
 Options:
   -h, --help            Show help message and exit
+
   -l LIB                Add additional library (absolute path)
 
                         This option can be given multiple times.
 
   --strip               Strip binaries before adding to archive (reduces size)
   --no-compress         Don't compress the archive (increases size)
+  --bundle-dir BUNDLE_DIR
+                        The directory that the program extracts to at runtime. When not specified, staticx extracts to ``/tmp/staticx-XXXXXX``.
+  --prog-name PROG_NAME
+                        The name that the program extracts to at runtime. When not specified, staticx uses the name of the input program.
   --loglevel LEVEL      Set the logging level (default: WARNING)
 
                         Options: DEBUG,INFO,WARNING,ERROR,CRITICAL
@@ -70,6 +76,5 @@ Run-time Information
 --------------------
 StaticX sets the following environment variables for the wrapped user program:
 
-- ``STATICX_BUNDLE_DIR``: The absolute path of the "bundle" directory, the
-  temporary dir where the archive has been extracted.
-- ``STATICX_PROG_PATH``: The absolute path of the program being executed.
+- ``STATICX_BUNDLE_DIR``: The absolute path of the "bundle" directory, a temporary directory, where the archive has been extracted.
+- ``STATICX_PROG_PATH``: The absolute path of the program being executed (not the extracted program in the bundle directory).

staticx/__main__.py

@@ -24,6 +24,10 @@ def parse_args():
             help = 'Strip binaries before adding to archive (reduces size)')
     ap.add_argument('--no-compress', action='store_true',
             help = "Don't compress the archive (increases size)")
+    ap.add_argument('--bundle-dir',
+            help = 'The directory that the program extracts to at runtime. When not specified, staticx extracts to /tmp/staticx-XXXXXX.')
+    ap.add_argument('--prog-name',
+            help = 'The name that the program extracts to at runtime. When not specified, staticx uses the name of the input program.')
 
     # Special / output-related options
     ap.add_argument('-V', '--version', action='version',
@@ -50,8 +54,9 @@ def main():
                 libs = args.libs,
                 strip = args.strip,
                 compress = not args.no_compress,
-                debug = args.debug,
-                )
+                bundle_dir = args.bundle_dir,
+                prog_name = args.prog_name,
+                debug = args.debug)
     except Error as e:
         if args.debug:
             raise

staticx/api.py

@@ -23,15 +23,21 @@ class StaticxGenerator:
     """StaticxGenerator is responsible for producing a staticx-ified executable.
     """
 
-    def __init__(self, prog, strip=False, compress=True, debug=False, cleanup=True):
+    def __init__(self, prog, strip=False, compress=True, bundle_dir=None, prog_name=None, debug=False, cleanup=True):
         """
-        Parameters:
-        prog:   Dynamic executable to staticx
-        debug:  Run in debug mode (use debug bootloader)
+            Parameters:
+            prog:       Dynamic executable to staticx
+            strip:      Strip binaries to reduce size
+            compress:   Whether or not to compress the archive
+            bundle_dir: The directory that the program extracts to at runtime
+            prog_name:  The name that the program extracts to at runtime
+            debug:      Run in debug mode (use debug bootloader)
         """
         self.orig_prog = prog
         self.strip = strip
         self.compress = compress
+        self.bundle_dir = bundle_dir
+        self.prog_name = prog_name
         self.debug = debug
         self.cleanup = cleanup
 
@@ -133,8 +139,10 @@ def generate(self, output):
         with self.sxar as ar:
             run_hooks(self)
 
-            ar.add_program(self.tmpprog, basename(self.orig_prog))
+            ar.add_program(self.tmpprog, self.prog_name or basename(self.orig_prog))
             ar.add_interp_symlink(orig_interp)
+            if self.bundle_dir is not None:
+                ar.add_bundle_dir_symlink(self.bundle_dir)
 
             # Add all of the libraries
             for libpath in get_shobj_deps(self.orig_prog):
@@ -294,15 +302,18 @@ def _fixup_prog(self):
                   force_rpath=True, no_default_lib=True)
 
 
-def generate(prog, output, libs=None, strip=False, compress=True, debug=False):
+def generate(prog, output, libs=None, strip=False, compress=True, bundle_dir=None, prog_name=None, debug=False):
     """Main API: Generate a staticx executable
 
     Parameters:
-    prog:   Dynamic executable to staticx
-    output: Path to result
-    libs: Extra libraries to include
-    strip: Strip binaries to reduce size
-    debug: Run in debug mode (use debug bootloader)
+    prog:       Dynamic executable to staticx
+    output:     Path to result
+    libs:       Extra libraries to include
+    strip:      Strip binaries to reduce size
+    compress:   Whether or not to compress the archive
+    bundle_dir: The directory that the program extracts to at runtime
+    prog_name:  The name that the program extracts to at runtime
+    debug:      Run in debug mode (use debug bootloader)
     """
 
     logging.info(f"Running StaticX version {__version__}")
@@ -319,8 +330,9 @@ def generate(prog, output, libs=None, strip=False, compress=True, debug=False):
             prog=prog,
             strip=strip,
             compress=compress,
-            debug=debug,
-            )
+            bundle_dir=bundle_dir,
+            prog_name=prog_name,
+            debug=debug)
     with gen:
         for lib in (libs or []):
             gen.add_library(lib)

staticx/archive.py

@@ -129,3 +129,7 @@ def add_file(self, path, arcname=None):
     def add_interp_symlink(self, interp):
         """Add symlink for ld.so interpreter"""
         self.add_symlink(INTERP_FILENAME, basename(interp))
+
+    def add_bundle_dir_symlink(self, bundle_dir):
+        """Adds a symlink that holds the path that the bundle directory will be moved to."""
+        self.add_symlink(BUNDLE_DIR_FILENAME, bundle_dir)

staticx/constants.py

@@ -1,6 +1,7 @@
-ARCHIVE_SECTION = ".staticx.archive"
-INTERP_FILENAME = ".staticx.interp"
-PROG_FILENAME   = ".staticx.prog"
+ARCHIVE_SECTION     = ".staticx.archive"
+INTERP_FILENAME     = ".staticx.interp"
+PROG_FILENAME       = ".staticx.prog"
+BUNDLE_DIR_FILENAME = ".staticx.bundle-dir"
 
 MAX_INTERP_LEN = 256
 MAX_RPATH_LEN = 256

test/bundle-dir-prog-name.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+set -e
+
+echo -e "\n\n--------------------------------------------------------------------------------"
+echo -e "Test StaticX --bundle-dir and --prog-name options."
+
+cd "$(dirname "${BASH_SOURCE[0]}")"
+
+app="$(which sh)"
+outfile="./sh.staticx"
+
+# The values we're going to be testing for.
+bundle_dir=$(mktemp --dry-run --tmpdir -d systemd-private-60ce0209a865480b817f3623184c43e2-dmesg.service-XXXXXX)
+prog_name="tmp"
+
+# Make a staticx executable from bash so we can check the STATICX_ env vars to know the bundle directory and program path.
+echo -e "\nMaking staticx executable (\$STATICX_FLAGS=$STATICX_FLAGS):"
+staticx $STATICX_FLAGS --bundle-dir $bundle_dir --prog-name $prog_name $app $outfile
+
+# Verify STATICX_BUNDLE_DIR matches the `--bundle-dir` option.
+test_bundle_dir=$($outfile -c 'echo $STATICX_BUNDLE_DIR')
+echo "STATICX_BUNDLE_DIR: $test_bundle_dir"
+if [[ "$test_bundle_dir" != "$bundle_dir" ]]; then
+    echo "STATICX_BUNDLE_DIR does not match --bundle-dir: \"$test_bundle_dir\" != \"$bundle_dir\""
+    exit 1
+fi
+
+# Verify that the program is renamed to `--prog-name` when specified.
+test_prog_name=$($outfile -c 'basename $0')
+echo "The program name is: $test_prog_name"
+if [[ "$test_prog_name" != "$prog_name" ]]; then
+    echo "The program name does not match --prog-name: \"$test_prog_name\" != \"$prog_name\""
+    exit 1
+fi

test/run_all.sh

@@ -9,6 +9,9 @@ cd "$(dirname "${BASH_SOURCE[0]}")"
 # Test environment variables
 ./staticx-env-vars.sh
 
+# Test --bundle-dir and --prog-name options
+./bundle-dir-prog-name.sh
+
 # Run test an executable linked against musl-libc
 musl/run_test.sh