/*    Copyright 2012 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

#include <cstdlib>
#include <string>

#include <kvm.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/vmmeter.h>
#include <unistd.h>

#include "mongo/util/scopeguard.h"
#include "processinfo.h"

namespace mongo {

    ProcessInfo::ProcessInfo(ProcessId pid) : _pid( pid ) {
    }

    ProcessInfo::~ProcessInfo() {
    }

    /**
     * Get a sysctl string value by name.  Use string specialization by default.
     */
    template <typename T>
    int getSysctlByIDWithDefault(const int *sysctlID, const int idLen,
                                   const T& defaultValue,
                                   T* result);

    template <>
    int getSysctlByIDWithDefault<uintptr_t>(const int *sysctlID,
                                              const int idLen,
                                              const uintptr_t& defaultValue,
                                              uintptr_t* result) {
        uintptr_t value = 0;
        size_t len = sizeof(value);
        if (sysctl(sysctlID, idLen, &value, &len, NULL, 0) == -1) {
            *result = defaultValue;
            return errno;
        }
        if (len > sizeof(value)) {
            *result = defaultValue;
            return EINVAL;
        }

        *result = value;
        return 0;
    }

    template <>
    int getSysctlByIDWithDefault<string>(const int *sysctlID,
                                         const int idLen,
                                           const string& defaultValue,
                                           string* result) {
        char value[256] = {0};
        size_t len = sizeof(value);
        if (sysctl(sysctlID, idLen, &value, &len, NULL, 0) == -1) {
            *result = defaultValue;
            return errno;
        }
        *result = value;
        return 0;
    }

    bool ProcessInfo::checkNumaEnabled() {
        return false;
    }

    int ProcessInfo::getVirtualMemorySize() {
        kvm_t *kd = NULL;
        int cnt = 0;
        char err[_POSIX2_LINE_MAX] = {0};
        if ((kd = kvm_openfiles(NULL, NULL, NULL, KVM_NO_FILES, err)) == NULL) {
            log() << "Unable to get virt mem size: " << err << endl;
            return -1;
        }

        kinfo_proc * task = kvm_getprocs(kd, KERN_PROC_PID, _pid.toNative(),
                sizeof(kinfo_proc), &cnt);
        kvm_close(kd);
        return ((task->p_vm_dsize + task->p_vm_ssize + task->p_vm_tsize) *
               sysconf( _SC_PAGESIZE )) / 1048576;
    }

    int ProcessInfo::getResidentSize() {
        kvm_t *kd = NULL;
        int cnt = 0;
        char err[_POSIX2_LINE_MAX] = {0};
        if ((kd = kvm_openfiles(NULL, NULL, NULL, KVM_NO_FILES, err)) == NULL) {
            log() << "Unable to get res mem size: " << err << endl;
            return -1;
        }
        kinfo_proc * task = kvm_getprocs(kd, KERN_PROC_PID, _pid.toNative(),
                sizeof(kinfo_proc), &cnt);
        kvm_close(kd);
        return (task->p_vm_rssize * sysconf( _SC_PAGESIZE )) / 1048576; // convert from pages to MB
    }

    void ProcessInfo::SystemInfo::collectSystemInfo() {
        osType = "BSD";
        osName = "OpenBSD";
        int mib[2];

        mib[0] = CTL_KERN;
        mib[1] = KERN_VERSION;
        int status = getSysctlByIDWithDefault(mib, 2, string("unknown"), &osVersion);
        if (status != 0)
            log() << "Unable to collect OS Version. (errno: " 
                  << status << " msg: " << strerror(status) << ")" << endl;

        mib[0] = CTL_HW;
        mib[1] = HW_MACHINE;
        status = getSysctlByIDWithDefault(mib, 2, string("unknown"), &cpuArch);
        if (status != 0)
            log() << "Unable to collect Machine Architecture. (errno: "
                  << status << " msg: " << strerror(status) << ")" << endl;
        addrSize = cpuArch.find("64") != std::string::npos ? 64 : 32;

        uintptr_t numBuffer;
        uintptr_t defaultNum = 1;
        mib[0] = CTL_HW;
        mib[1] = HW_PHYSMEM;
        status = getSysctlByIDWithDefault(mib, 2, defaultNum, &numBuffer);
        memSize = numBuffer;
        if (status != 0)
            log() << "Unable to collect Physical Memory. (errno: "
                  << status << " msg: " << strerror(status) << ")" << endl;

        mib[0] = CTL_HW;
        mib[1] = HW_NCPU;
        status = getSysctlByIDWithDefault(mib, 2, defaultNum, &numBuffer);
        numCores = numBuffer;
        if (status != 0)
            log() << "Unable to collect Number of CPUs. (errno: "
                  << status << " msg: " << strerror(status) << ")" << endl;

        pageSize = static_cast<unsigned long long>(sysconf(_SC_PAGESIZE));

        hasNuma = checkNumaEnabled();
    }

    void ProcessInfo::getExtraInfo( BSONObjBuilder& info ) {
    }

    bool ProcessInfo::supported() {
        return true;
    }

    bool ProcessInfo::blockCheckSupported() {
        return true;
    }

    bool ProcessInfo::blockInMemory(const void* start) {
         char x = 0;
         if (mincore((void*)alignToStartOfPage(start), getPageSize(), &x)) {
             log() << "mincore failed: " << errnoWithDescription() << endl;
             return 1;
         }
         return x & 0x1;
    }

    bool ProcessInfo::pagesInMemory(const void* start, size_t numPages, vector<char>* out) {
        out->resize(numPages);
        // int mincore(const void *addr, size_t len, char *vec);
        if (mincore((void*)alignToStartOfPage(start), numPages * getPageSize(),
                    &(out->front()))) {
            log() << "mincore failed: " << errnoWithDescription() << endl;
            return false;
        }
        for (size_t i = 0; i < numPages; ++i) {
            (*out)[i] = 0x1;
        }
        return true;
    }
}
