ybelkadi created this revision. ybelkadi added reviewers: labath, ovyalov. ybelkadi added a subscriber: lldb-commits.
Due to fork()/execve(), the launched inferior inherits the signal mask of its parent (lldb-server). But because lldb-server modifies its signal mask (It blocks SIGCHLD, for example), the inferior starts with some signals being initially blocked. One consequence is that TestCallThatRestarts.ExprCommandThatRestartsTestCase (test/expression_command/call-restarts) fails because sigchld_handler() in lotta-signals.c is not called, due to the SIGCHLD signal being blocked. To prevent the signal masking done by lldb-server from affecting the created inferior, the signal mask of the inferior is now cleared before the execve(). http://reviews.llvm.org/D12138 Files: source/Plugins/Process/Linux/NativeProcessLinux.cpp Index: source/Plugins/Process/Linux/NativeProcessLinux.cpp =================================================================== --- source/Plugins/Process/Linux/NativeProcessLinux.cpp +++ source/Plugins/Process/Linux/NativeProcessLinux.cpp @@ -554,7 +554,8 @@ eDupStderrFailed, eChdirFailed, eExecFailed, - eSetGidFailed + eSetGidFailed, + eSetSigMaskFailed }; // Child process. @@ -629,6 +630,12 @@ } } + // Clear the signal mask to prevent the child from being affected by + // any masking done by the parent. + sigset_t set; + if (sigemptyset(&set) != 0 || pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0) + exit(eSetSigMaskFailed); + // Execute. We should never return... execve(argv[0], const_cast<char *const *>(argv), @@ -686,6 +693,9 @@ case eSetGidFailed: error.SetErrorString("Child setgid failed."); break; + case eSetSigMaskFailed: + error.SetErrorString("Child failed to set signal mask."); + break; default: error.SetErrorString("Child returned unknown exit status."); break;
Index: source/Plugins/Process/Linux/NativeProcessLinux.cpp =================================================================== --- source/Plugins/Process/Linux/NativeProcessLinux.cpp +++ source/Plugins/Process/Linux/NativeProcessLinux.cpp @@ -554,7 +554,8 @@ eDupStderrFailed, eChdirFailed, eExecFailed, - eSetGidFailed + eSetGidFailed, + eSetSigMaskFailed }; // Child process. @@ -629,6 +630,12 @@ } } + // Clear the signal mask to prevent the child from being affected by + // any masking done by the parent. + sigset_t set; + if (sigemptyset(&set) != 0 || pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0) + exit(eSetSigMaskFailed); + // Execute. We should never return... execve(argv[0], const_cast<char *const *>(argv), @@ -686,6 +693,9 @@ case eSetGidFailed: error.SetErrorString("Child setgid failed."); break; + case eSetSigMaskFailed: + error.SetErrorString("Child failed to set signal mask."); + break; default: error.SetErrorString("Child returned unknown exit status."); break;
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