[Bug 267752] devel/valgrind: Valgrind fails on programs compiled with -fsanitize=address

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=267752

--- Comment #4 from Paul Floyd <pjfloyd@wanadoo.fr> ---

'valgrind' is just a small exe. It modifies the environment to add some
LD_PRELOADs and adds an env var called VALGRIND_LAUNCHER. Then it execs the
tool (memcheck-amd64-freebsd for instance).

The tool code that fails is

   VG_(debugLog)(1, "main", "Getting launcher's name ...\n");
   VG_(name_of_launcher) = VG_(getenv)(VALGRIND_LAUNCHER);
   if (VG_(name_of_launcher) == NULL) {
      VG_(printf)("valgrind: You cannot run '%s' directly.\n", argv[0]);
      VG_(printf)("valgrind: You should use $prefix/bin/valgrind.\n");
      VG_(exit)(1);
   }

And here is the launcher code

   /* Figure out the name of this executable (viz, the launcher), so
      we can tell stage2.  stage2 will use the name for recursive
      invocations of valgrind on child processes. */
   memset(launcher_name, 0, PATH_MAX+1);

   oid[0] = CTL_KERN;
   oid[1] = KERN_PROC;
   oid[2] = KERN_PROC_PATHNAME;
   oid[3] = getpid();
   len = PATH_MAX;
   r = sysctl(oid, 4, launcher_name, &len, 0, 0);
   if (r != 0) {
      fprintf(stderr, "valgrind: warning (non-fatal): "
              "sysctl(\"kern.proc.pathname\") failed.\n");
      fprintf(stderr, "valgrind: continuing, however --trace-children=yes "
              "will not work.\n");
   }

   /* tediously augment the env: VALGRIND_LAUNCHER=launcher_name */
   new_line = malloc(strlen(VALGRIND_LAUNCHER) + 1
                     + strlen(launcher_name) + 1);
   if (new_line == NULL)
      barf("malloc of new_line failed.");
   strcpy(new_line, VALGRIND_LAUNCHER);
   strcat(new_line, "=");
   strcat(new_line, launcher_name);

   for (j = 0; envp[j]; j++)
      ;
   new_env = malloc((j+2) * sizeof(char*));

Does your exe run a bit and then fork/exec?
You you set --trace-children=yes (in your valgrind ini file)?

I don't know how the sanitized exe is interfering with this, it is all well
before the guest even gets loaded. Either the sysctl isn't working correctly or
the env var is getting corrupted.

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