--- /dev/null
+/* Copyright © 2013, Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/* dladdr is a glibc extension */
+#define _GNU_SOURCE
+#include <dlfcn.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <string.h>
+
+#include "dlwrap.h"
+
+#define STRNCMP_LITERAL(var, literal) \
+ strncmp ((var), (literal), sizeof (literal) - 1)
+
+void *libfips_handle;
+
+typedef void * (* fips_dlopen_t)(const char * filename, int flag);
+typedef void * (* fips_dlsym_t)(void *handle, const char *symbol);
+
+/* Many (most?) OpenGL programs dlopen libGL.so.1 rather than linking
+ * against it directly, which means they would not be seeing our
+ * wrapped GL symbols via LD_PRELOAD. So we catch the dlopen in a
+ * wrapper here and redirect it to our library.
+ */
+void *
+dlopen (const char *filename, int flag)
+{
+ Dl_info info;
+
+ /* Not libGL, so just return real dlopen */
+ if (STRNCMP_LITERAL (filename, "libGL.so"))
+ return dlwrap_real_dlopen (filename, flag);
+
+ /* Redirect all dlopens to libGL to our own wrapper library.
+ * We find our own filename by looking up this very function
+ * (that is, this "dlopen"), with dladdr).*/
+ if (dladdr (dlopen, &info)) {
+ libfips_handle = dlwrap_real_dlopen (info.dli_fname, flag);
+ return libfips_handle;
+ } else {
+ fprintf (stderr, "Error: Failed to redirect dlopen of %s:\n",
+ filename);
+ exit (1);
+ }
+}
+
+void *
+dlwrap_real_dlopen (const char *filename, int flag)
+{
+ fips_dlopen_t real_dlopen = NULL;
+
+ if (! real_dlopen) {
+ real_dlopen = (fips_dlopen_t) dlwrap_real_dlsym (RTLD_NEXT, "dlopen");
+ if (! real_dlopen) {
+ fprintf (stderr, "Error: Failed to find symbol for dlopen.\n");
+ exit (1);
+ }
+ }
+
+ return real_dlopen (filename, flag);
+}
+
+/* Since we redirect a dlopen of libGL.so to libfips we need to ensure
+ * that dlysm succeeds for all functions that might be defined in the
+ * real, underlying libGL library. But we're far too lazy to implement
+ * wrappers for function that would simply pass-through, so instead we
+ * also wrap dlysm and arrange for it to pass things through with
+ * RTLD_next if libfips does not have the function desired.
+*/
+void *
+dlsym (void *handle, const char *name)
+{
+ static void *libgl_handle = NULL;
+ static void *symbol;
+
+ /* All gl symbols are preferentially looked up in libfips. */
+ if (STRNCMP_LITERAL (name, "gl") == 0) {
+ symbol = dlwrap_real_dlsym (libfips_handle, name);
+ if (symbol)
+ return symbol;
+ }
+
+ /* Failing that, anything specifically requested from the
+ * libfips library should be redirected to a real GL
+ * library. */
+ if (handle == libfips_handle) {
+ if (! libgl_handle)
+ libgl_handle = dlwrap_real_dlopen ("libGL.so.1", RTLD_LAZY);
+ return dlwrap_real_dlsym (libgl_handle, name);
+ }
+
+ /* And anything else is some unrelated dlsym. Just pass it through. */
+ return dlwrap_real_dlsym (handle, name);
+}
+
+extern void *__dlsym (void *handle, const char *name);
+void *
+dlwrap_real_dlsym (void *handle, const char *name)
+{
+ static fips_dlsym_t real_dlsym = NULL;
+
+ if (! real_dlsym) {
+ /* FIXME: This brute-force, hard-coded searching for a versioned
+ * symbol is really ugly. The only reason I'm doing this is because
+ * I need some way to lookup the "dlsym" function in libdl, but
+ * I can't use 'dlsym' to do it. So dlvsym works, but forces me
+ * to guess what the right version is.
+ *
+ * Potential fixes here:
+ *
+ * 1. Use libelf to actually inspect libdl.so and
+ * find the right version, (finding the right
+ * libdl.so can be made easier with
+ * dl_iterate_phdr).
+ *
+ * 2. Use libelf to find the offset of the 'dlsym'
+ * symbol within libdl.so, (and then add this to
+ * the base address at which libdl.so is loaded
+ * as reported by dl_iterate_phdr).
+ *
+ * In the meantime, I'll just keep augmenting this
+ * hard-coded version list as people report bugs. */
+ const char *version[] = {
+ "GLIBC_2.2.5",
+ "GLIBC_2.0"
+ };
+ int num_versions = sizeof(version) / sizeof(version[0]);
+ int i;
+ for (i = 0; i < num_versions; i++) {
+ real_dlsym = (fips_dlsym_t) dlvsym (RTLD_NEXT, "dlsym",
+ version[i]);
+ if (real_dlsym)
+ break;
+ }
+ if (i == num_versions) {
+ fprintf (stderr, "Internal error: Failed to find real dlsym\n");
+ fprintf (stderr,
+"This may be a simple matter of fips not knowing about the version of GLIBC that\n"
+"your program is using. Current known versions are:\n\n\t");
+ for (i = 0; i < num_versions; i++)
+ fprintf (stderr, "%s ", version[i]);
+ fprintf(stderr,
+"\n\nYou can inspect your version by first finding libdl.so.2:\n"
+"\n"
+"\tldd <your-program> | grep libdl.so\n"
+"\n"
+"And then inspecting the version attached to the dlsym symbol:\n"
+"\n"
+"\treadelf -s /path/to/libdl.so.2 | grep dlsym\n"
+"\n"
+"And finally, adding the version to dlwrap.c:dlwrap_real_dlsym.\n");
+
+ exit (1);
+ }
+ }
+
+ return real_dlsym (handle, name);
+}
projects / fips / blobdiff