llvm-project/lldb/source/Host/freebsd/Host.cpp

//===-- source/Host/freebsd/Host.cpp ------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// C Includes
#include <stdio.h>
#include <dlfcn.h>
#include <execinfo.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/sysctl.h>
#include <sys/proc.h>

#include <sys/ptrace.h>
#include <sys/exec.h>
#include <machine/elf.h>

// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Core/Error.h"
#include "lldb/Host/Endian.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/HostInfo.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/StreamFile.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Core/Log.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Platform.h"

#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Utility/CleanUp.h"

#include "Plugins/Process/Utility/FreeBSDSignals.h"

#include "llvm/Support/Host.h"

extern "C" {
    extern char **environ;
}

using namespace lldb;
using namespace lldb_private;

void
Host::Backtrace (Stream &strm, uint32_t max_frames)
{
    char backtrace_path[] = "/tmp/lldb-backtrace-tmp-XXXXXX";
    int backtrace_fd = ::mkstemp (backtrace_path);
    if (backtrace_fd != -1)
    {
        std::vector<void *> frame_buffer (max_frames, NULL);
        int count = ::backtrace (&frame_buffer[0], frame_buffer.size());
        ::backtrace_symbols_fd (&frame_buffer[0], count, backtrace_fd);

        const off_t buffer_size = ::lseek(backtrace_fd, 0, SEEK_CUR);

        if (::lseek(backtrace_fd, 0, SEEK_SET) == 0)
        {
            char *buffer = (char *)::malloc (buffer_size);
            if (buffer)
            {
                ssize_t bytes_read = ::read (backtrace_fd, buffer, buffer_size);
                if (bytes_read > 0)
                    strm.Write(buffer, bytes_read);
                ::free (buffer);
            }
        }
        ::close (backtrace_fd);
        ::unlink (backtrace_path);
    }
}

size_t
Host::GetEnvironment (StringList &env)
{
    char *v;
    char **var = environ;
    for (; var != NULL && *var != NULL; ++var)
    {
        v = strchr(*var, (int)'-');
        if (v == NULL)
            continue;
        env.AppendString(v);
    }
    return env.GetSize();
}

static bool
GetFreeBSDProcessArgs (const ProcessInstanceInfoMatch *match_info_ptr,
                      ProcessInstanceInfo &process_info)
{
    if (process_info.ProcessIDIsValid())
    {
        int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_ARGS, (int)process_info.GetProcessID() };

        char arg_data[8192];
        size_t arg_data_size = sizeof(arg_data);
        if (::sysctl (mib, 4, arg_data, &arg_data_size , NULL, 0) == 0)
        {
            DataExtractor data (arg_data, arg_data_size, lldb::endian::InlHostByteOrder(), sizeof(void *));
            lldb::offset_t offset = 0;
            const char *cstr;

            cstr = data.GetCStr (&offset);
            if (cstr)
            {
                process_info.GetExecutableFile().SetFile(cstr, false);

                if (!(match_info_ptr == NULL ||
                    NameMatches (process_info.GetExecutableFile().GetFilename().GetCString(),
                                 match_info_ptr->GetNameMatchType(),
                                 match_info_ptr->GetProcessInfo().GetName())))
                    return false;

                Args &proc_args = process_info.GetArguments();
                while (1)
                {
                    const uint8_t *p = data.PeekData(offset, 1);
                    while ((p != NULL) && (*p == '\0') && offset < arg_data_size)
                    {
                        ++offset;
                        p = data.PeekData(offset, 1);
                    }
                    if (p == NULL || offset >= arg_data_size)
                        return true;

                    cstr = data.GetCStr(&offset);
                    if (cstr)
                        proc_args.AppendArgument(cstr);
                    else
                        return true;
                }
            }
        }
    }
    return false;
}

static bool
GetFreeBSDProcessCPUType (ProcessInstanceInfo &process_info)
{
    if (process_info.ProcessIDIsValid())
    {
        process_info.GetArchitecture() = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
        return true;
    }
    process_info.GetArchitecture().Clear();
    return false;
}

static bool
GetFreeBSDProcessUserAndGroup(ProcessInstanceInfo &process_info)
{
    struct kinfo_proc proc_kinfo;
    size_t proc_kinfo_size;

    if (process_info.ProcessIDIsValid())
    {
        int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PID,
            (int)process_info.GetProcessID() };
        proc_kinfo_size = sizeof(struct kinfo_proc);

        if (::sysctl (mib, 4, &proc_kinfo, &proc_kinfo_size, NULL, 0) == 0)
        {
            if (proc_kinfo_size > 0)
            {
                process_info.SetParentProcessID (proc_kinfo.ki_ppid);
                process_info.SetUserID (proc_kinfo.ki_ruid);
                process_info.SetGroupID (proc_kinfo.ki_rgid);
                process_info.SetEffectiveUserID (proc_kinfo.ki_uid);
                if (proc_kinfo.ki_ngroups > 0)
                    process_info.SetEffectiveGroupID (proc_kinfo.ki_groups[0]);
                else
                    process_info.SetEffectiveGroupID (UINT32_MAX);
                return true;
            }
        }
    }
    process_info.SetParentProcessID (LLDB_INVALID_PROCESS_ID);
    process_info.SetUserID (UINT32_MAX);
    process_info.SetGroupID (UINT32_MAX);
    process_info.SetEffectiveUserID (UINT32_MAX);
    process_info.SetEffectiveGroupID (UINT32_MAX);
    return false;
}

uint32_t
Host::FindProcesses (const ProcessInstanceInfoMatch &match_info, ProcessInstanceInfoList &process_infos)
{
    std::vector<struct kinfo_proc> kinfos;

    int mib[3] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL };

    size_t pid_data_size = 0;
    if (::sysctl (mib, 3, NULL, &pid_data_size, NULL, 0) != 0)
        return 0;

    // Add a few extra in case a few more show up
    const size_t estimated_pid_count = (pid_data_size / sizeof(struct kinfo_proc)) + 10;

    kinfos.resize (estimated_pid_count);
    pid_data_size = kinfos.size() * sizeof(struct kinfo_proc);

    if (::sysctl (mib, 3, &kinfos[0], &pid_data_size, NULL, 0) != 0)
        return 0;

    const size_t actual_pid_count = (pid_data_size / sizeof(struct kinfo_proc));

    bool all_users = match_info.GetMatchAllUsers();
    const ::pid_t our_pid = getpid();
    const uid_t our_uid = getuid();
    for (size_t i = 0; i < actual_pid_count; i++)
    {
        const struct kinfo_proc &kinfo = kinfos[i];
        const bool kinfo_user_matches = (all_users ||
                                         (kinfo.ki_ruid == our_uid) ||
                                         // Special case, if lldb is being run as root we can attach to anything.
                                         (our_uid == 0)
                                         );

        if (kinfo_user_matches == false      || // Make sure the user is acceptable
            kinfo.ki_pid == our_pid          || // Skip this process
            kinfo.ki_pid == 0                || // Skip kernel (kernel pid is zero)
            kinfo.ki_stat == SZOMB    || // Zombies are bad, they like brains...
            kinfo.ki_flag & P_TRACED  || // Being debugged?
            kinfo.ki_flag & P_WEXIT)     // Working on exiting
            continue;

        // Every thread is a process in FreeBSD, but all the threads of a single process
        // have the same pid. Do not store the process info in the result list if a process
        // with given identifier is already registered there.
        bool already_registered = false;
        for (uint32_t pi = 0;
             !already_registered &&
             (const int)kinfo.ki_numthreads > 1 &&
             pi < (const uint32_t)process_infos.GetSize(); pi++)
            already_registered = (process_infos.GetProcessIDAtIndex(pi) == (uint32_t)kinfo.ki_pid);

        if (already_registered)
            continue;

        ProcessInstanceInfo process_info;
        process_info.SetProcessID (kinfo.ki_pid);
        process_info.SetParentProcessID (kinfo.ki_ppid);
        process_info.SetUserID (kinfo.ki_ruid);
        process_info.SetGroupID (kinfo.ki_rgid);
        process_info.SetEffectiveUserID (kinfo.ki_svuid);
        process_info.SetEffectiveGroupID (kinfo.ki_svgid);

        // Make sure our info matches before we go fetch the name and cpu type
        if (match_info.Matches (process_info) &&
            GetFreeBSDProcessArgs (&match_info, process_info))
        {
            GetFreeBSDProcessCPUType (process_info);
            if (match_info.Matches (process_info))
                process_infos.Append (process_info);
        }
    }

    return process_infos.GetSize();
}

bool
Host::GetProcessInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info)
{
    process_info.SetProcessID(pid);

    if (GetFreeBSDProcessArgs(NULL, process_info))
    {
        // should use libprocstat instead of going right into sysctl?
        GetFreeBSDProcessCPUType(process_info);
        GetFreeBSDProcessUserAndGroup(process_info);
        return true;
    }

    process_info.Clear();
    return false;
}

lldb::DataBufferSP
Host::GetAuxvData(lldb_private::Process *process)
{
   int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_AUXV, 0 };
   size_t auxv_size = AT_COUNT * sizeof(Elf_Auxinfo);
   DataBufferSP buf_sp;

   std::unique_ptr<DataBufferHeap> buf_ap(new DataBufferHeap(auxv_size, 0));

   mib[3] = process->GetID();
   if (::sysctl(mib, 4, buf_ap->GetBytes(), &auxv_size, NULL, 0) == 0) {
           buf_sp.reset(buf_ap.release());
   } else {
           perror("sysctl failed on auxv");
   }

   return buf_sp;
}

const UnixSignalsSP&
Host::GetUnixSignals ()
{
    static const lldb_private::UnixSignalsSP s_unix_signals_sp (new FreeBSDSignals ());
    return s_unix_signals_sp;
}