elf/tst-glibc-hwcaps-prepend-cache.c

   1 /* Test that --glibc-hwcaps-prepend works, using dlopen and /etc/ld.so.cache.
   2    Copyright (C) 2020-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <dlfcn.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <support/check.h>
  25 #include <support/support.h>
  26 #include <support/xdlfcn.h>
  27 #include <support/xunistd.h>
  28
  29 /* Invoke /sbin/ldconfig with some error checking.  */
  30 static void
  31 run_ldconfig (void)
  32 {
  33   char *command = xasprintf ("%s/ldconfig", support_install_rootsbindir);
  34   TEST_COMPARE (system (command), 0);
  35   free (command);
  36 }
  37
  38 /* The library under test.  */
  39 #define SONAME "libmarkermod1.so"
  40
  41 static int
  42 do_test (void)
  43 {
  44   if (dlopen (SONAME, RTLD_NOW) != NULL)
  45     FAIL_EXIT1 (SONAME " is already on the search path");
  46
  47   /* Install the default implementation of libmarkermod1.so.  */
  48   xmkdirp ("/etc", 0777);
  49   support_write_file_string ("/etc/ld.so.conf", "/glibc-test/lib\n");
  50   xmkdirp ("/glibc-test/lib/glibc-hwcaps/prepend2", 0777);
  51   xmkdirp ("/glibc-test/lib/glibc-hwcaps/prepend3", 0777);
  52   {
  53     char *src = xasprintf ("%s/elf/libmarkermod1-1.so", support_objdir_root);
  54     support_copy_file (src, "/glibc-test/lib/" SONAME);
  55     free (src);
  56   }
  57   run_ldconfig ();
  58   {
  59     /* The default implementation can now be loaded.  */
  60     void *handle = xdlopen (SONAME, RTLD_NOW);
  61     int (*marker1) (void) = xdlsym (handle, "marker1");
  62     TEST_COMPARE (marker1 (), 1);
  63     xdlclose (handle);
  64   }
  65
  66   /* Add the first override to the directory that is searched last.  */
  67   {
  68     char *src = xasprintf ("%s/elf/libmarkermod1-2.so", support_objdir_root);
  69     support_copy_file (src, "/glibc-test/lib/glibc-hwcaps/prepend2/"
  70                        SONAME);
  71     free (src);
  72   }
  73   {
  74     /* This is still the first implementation.  The cache has not been
  75        updated.  */
  76     void *handle = xdlopen (SONAME, RTLD_NOW);
  77     int (*marker1) (void) = xdlsym (handle, "marker1");
  78     TEST_COMPARE (marker1 (), 1);
  79     xdlclose (handle);
  80   }
  81   run_ldconfig ();
  82   {
  83     /* After running ldconfig, it is the second implementation.  */
  84     void *handle = xdlopen (SONAME, RTLD_NOW);
  85     int (*marker1) (void) = xdlsym (handle, "marker1");
  86     TEST_COMPARE (marker1 (), 2);
  87     xdlclose (handle);
  88   }
  89
  90   /* Add the second override to the directory that is searched first.  */
  91   {
  92     char *src = xasprintf ("%s/elf/libmarkermod1-3.so", support_objdir_root);
  93     support_copy_file (src, "/glibc-test/lib/glibc-hwcaps/prepend3/"
  94                        SONAME);
  95     free (src);
  96   }
  97   {
  98     /* This is still the second implementation.  */
  99     void *handle = xdlopen (SONAME, RTLD_NOW);
 100     int (*marker1) (void) = xdlsym (handle, "marker1");
 101     TEST_COMPARE (marker1 (), 2);
 102     xdlclose (handle);
 103   }
 104   run_ldconfig ();
 105   {
 106     /* After running ldconfig, it is the third implementation.  */
 107     void *handle = xdlopen (SONAME, RTLD_NOW);
 108     int (*marker1) (void) = xdlsym (handle, "marker1");
 109     TEST_COMPARE (marker1 (), 3);
 110     xdlclose (handle);
 111   }
 112
 113   /* Remove the second override again, without running ldconfig.
 114      Ideally, this would revert to implementation 2.  However, in the
 115      current implementation, the cache returns exactly one file name
 116      which does not exist after unlinking, so the dlopen fails.  */
 117   xunlink ("/glibc-test/lib/glibc-hwcaps/prepend3/" SONAME);
 118   TEST_VERIFY (dlopen (SONAME, RTLD_NOW) == NULL);
 119   run_ldconfig ();
 120   {
 121     /* After running ldconfig, the second implementation is available
 122        once more.  */
 123     void *handle = xdlopen (SONAME, RTLD_NOW);
 124     int (*marker1) (void) = xdlsym (handle, "marker1");
 125     TEST_COMPARE (marker1 (), 2);
 126     xdlclose (handle);
 127   }
 128
 129   return 0;
 130 }
 131
 132 static void
 133 prepare (int argc, char **argv)
 134 {
 135   const char *no_restart = "no-restart";
 136   if (argc == 2 && strcmp (argv[1], no_restart) == 0)
 137     return;
 138   /* Re-execute the test with an explicit loader invocation.  */
 139   execl (support_objdir_elf_ldso,
 140          support_objdir_elf_ldso,
 141          "--glibc-hwcaps-prepend", "prepend3:prepend2",
 142          argv[0], no_restart,
 143          NULL);
 144   printf ("error: execv of %s failed: %m\n", argv[0]);
 145   _exit (1);
 146 }
 147
 148 #define PREPARE prepare
 149 #include <support/test-driver.c>