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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