Commit 8f23294b authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r366985: 

------------------------------------------------------------------------
r366985 | labath | 2019-07-25 08:38:33 +0200 (Thu, 25 Jul 2019) | 16 lines

LLGS: fix tracking execve on linux

Summary:
Due to a logic error, lldb-server ended up asserting/crashing every time
the debugged process attempted an execve(). This fixes the error, and
extends TestExec to work on other platforms too. The "extension"
consists of avoiding non-standard posix_spawn extensions and using the
classic execve() call, which should be available on any platform that
actually supports re-execing. I change the test decorator from
@skipUnlessDarwin to @skipIfWindows.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D65207
------------------------------------------------------------------------

llvm-svn: 367128
parent cb4f3533

lldb/packages/Python/lldbsuite/test/functionalities/exec/TestExec.py

+2 −2
Original line number Diff line number Diff line
@@ -18,17 +18,17 @@ class ExecTestCase(TestBase): 


    mydir = TestBase.compute_mydir(__file__)



    @skipUnlessDarwin

    @expectedFailureAll(archs=['i386'], bugnumber="rdar://28656532")

    @expectedFailureAll(oslist=["ios", "tvos", "watchos", "bridgeos"], bugnumber="rdar://problem/34559552") # this exec test has problems on ios systems

    @skipIfSanitized # rdar://problem/43756823

    @skipIfWindows

    def test_hitting_exec (self):

        self.do_test(False)



    @skipUnlessDarwin

    @expectedFailureAll(archs=['i386'], bugnumber="rdar://28656532")

    @expectedFailureAll(oslist=["ios", "tvos", "watchos", "bridgeos"], bugnumber="rdar://problem/34559552") # this exec test has problems on ios systems

    @skipIfSanitized # rdar://problem/43756823

    @skipIfWindows

    def test_skipping_exec (self):

        self.do_test(True)

lldb/packages/Python/lldbsuite/test/functionalities/exec/main.cpp

+11 −71
Original line number Diff line number Diff line 
#include <errno.h>

#include <mach/mach.h>

#include <signal.h>

#include <stdio.h>

#include <stdint.h>

#include <stdlib.h>

#include <spawn.h>

#include <unistd.h>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <libgen.h>

#include <string>

#include <unistd.h>



static void

exit_with_errno (int err, const char *prefix)

{

    if (err)

    {

        fprintf (stderr,

                 "%s%s",

                 prefix ? prefix : "",

                 strerror(err));

        exit (err);

    }

}



static pid_t

spawn_process (const char *progname,

               const char **argv,

               const char **envp,

               int &err)

{

    pid_t pid = 0;



    const posix_spawn_file_actions_t *file_actions = NULL;

    posix_spawnattr_t attr;

    err = posix_spawnattr_init (&attr);

    if (err)

        return pid;



    short flags = POSIX_SPAWN_SETEXEC | POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK;

    err = posix_spawnattr_setflags (&attr, flags);

    if (err == 0)

    {

        // Use the default signal masks

        sigset_t no_signals;

        sigset_t all_signals;

        sigemptyset (&no_signals);

        sigfillset (&all_signals);

        posix_spawnattr_setsigmask(&attr, &no_signals);

        posix_spawnattr_setsigdefault(&attr, &all_signals);



        err = posix_spawn (&pid,

                           progname,

                           file_actions,

                           &attr,

                           (char * const *)argv,

                           (char * const *)envp);

        

        posix_spawnattr_destroy(&attr);

    }

    return pid;

}



int 

main (int argc, char const **argv)

{

    char *buf = (char*) malloc (strlen (argv[0]) + 12);

    strlcpy (buf, argv[0], strlen (argv[0]) + 1);

int main(int argc, char const **argv) {

  char *buf = strdup(argv[0]); // Set breakpoint 1 here

  std::string directory_name(::dirname(buf));



  std::string other_program = directory_name + "/secondprog";

    int err = 0;    // Set breakpoint 1 here

    spawn_process (other_program.c_str(), argv, NULL, err);

    if (err)

        exit_with_errno (err, "posix_spawn x86_64 error");

    return 0;

  execve(other_program.c_str(), const_cast<char *const *>(argv), nullptr);

  perror("execve");

  abort();

}

lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp

+3 −6
Original line number Diff line number Diff line
@@ -599,12 +599,9 @@ void NativeProcessLinux::MonitorSIGTRAP(const siginfo_t &info, 
    // which only copies the main thread.

    LLDB_LOG(log, "exec received, stop tracking all but main thread");



    for (auto i = m_threads.begin(); i != m_threads.end();) {

      if ((*i)->GetID() == GetID())

        i = m_threads.erase(i);

      else

        ++i;

    }

    llvm::erase_if(m_threads, [&](std::unique_ptr<NativeThreadProtocol> &t) {

      return t->GetID() != GetID();

    });

    assert(m_threads.size() == 1);

    auto *main_thread = static_cast<NativeThreadLinux *>(m_threads[0].get());