Use the right type for pid_t on FreeBSD

[davide]

Summary

pid_t is int32_t on FreeBSD, not uint64_t. I think it's better committing a small sin her rather than changing it globally.

[davide]

Updated patch after suggestion from Chaoren on IRC.

[emaste]

I'm not sure it's uint64_t anywhere, actually, and I think PseudoTerminal::Fork ought to return a ::pid_t as well. But this change is OK as long as it works - specifically, the if ((pid = terminal.Fork(err_str, err_len)) == -1)

[davide]

Just for the records, it's uint64_t as defined in lldb_types.h. pid_t is int32_t at least on FreeBSD and Mac OS (didn't check Linux). Also, clang complains about signed vs unsigned comparison:

../tools/lldb/source/Plugins/Process/FreeBSD/ProcessMonitor.cpp:973:49: warning: comparison of integers of different signs: 'lldb::pid_t' (aka 'unsigned long') and 'int' [-Wsign-compare]

if ((pid = terminal.Fork(err_str, err_len)) == -1)
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  ^  ~~

so actually this change make the logic correct in case fork() fails and therefore returns -1 to the parent.

[zturner]

all of the lldb:: types are 64 bit because it needs to be able to hold a
pid of any platform (if you are remote debugging for example). You need to
cast to and from ::pid_t inside your host layer

[emaste]

In D8491#144558, @zturner wrote:

all of the lldb:: types are 64 bit because it needs to be able to hold a
pid of any platform (if you are remote debugging for example). You need to
cast to and from ::pid_t inside your host layer

Right - what I meant is I'm not aware of any platform that has a 64-bit pid type.

[zturner]

I'm not either fwiw, just explaining the motivation for Davide :)

[davide]

Thank for the clarification Zachary. While at it, are you OK with this patch or you have ohter comments?

[zturner]

If Ed says it's fine then I'm fine too.

lldb/trunk/source/Plugins/Process/FreeBSD/ProcessMonitor.cpp

ProcessMonitor::Launch(LaunchArgs *args)
     const char *stdin_path = args->m_stdin_path;
     const char *stdout_path = args->m_stdout_path;
     const char *stderr_path = args->m_stderr_path;
     const char *working_dir = args->m_working_dir;
 
     lldb_utility::PseudoTerminal terminal;
     const size_t err_len = 1024;
     char err_str[err_len];
-    lldb::pid_t pid;
+    ::pid_t pid;
 
     // Propagate the environment if one is not supplied.
     if (envp == NULL || envp[0] == NULL)
         envp = const_cast<const char **>(environ);
 
     if ((pid = terminal.Fork(err_str, err_len)) == -1)
     {
         args->m_error.SetErrorToGenericError();