/* -*-mode:c++;c-file-style:"bsd";c-basic-offset:4;indent-tabs-mode:nil-*-
    CCpp.cpp

    Copyright (C) 2009  Zdenek Prikryl (zprikryl@redhat.com)
    Copyright (C) 2009  RedHat inc.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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 General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
    */

#include <sys/wait.h>
#include <fstream>
#include <sstream>
#include <set>
#include <iomanip>
#include <nss.h>
#include <sechash.h>
#include <sysexits.h>
#include "abrtlib.h"
#include "CCpp.h"
#include "ABRTException.h"
#include "DebugDump.h"
#include "CommLayerInner.h"
#include "Polkit.h"

using namespace std;

#define CORE_PATTERN_IFACE      "/proc/sys/kernel/core_pattern"
#define CORE_PATTERN            "|"CCPP_HOOK_PATH" "DEBUG_DUMPS_DIR" %p %s %u"

#define FILENAME_COREDUMP       "coredump"
#define FILENAME_BACKTRACE      "backtrace"
#define FILENAME_MEMORYMAP      "memorymap"

#define DEBUGINFO_CACHE_DIR     LOCALSTATEDIR"/cache/abrt-di"

CAnalyzerCCpp::CAnalyzerCCpp() :
    m_bMemoryMap(false),
    m_bInstallDebugInfo(true),
    m_nDebugInfoCacheMB(4000)
{}

static string CreateHash(const char *pInput)
{
    string ret;
    HASHContext* hc;
    unsigned char hash[SHA1_LENGTH];
    unsigned int len;

    hc = HASH_Create(HASH_AlgSHA1);
    if (!hc)
    {
        error_msg_and_die("HASH_Create(HASH_AlgSHA1) failed"); /* paranoia */
    }
    HASH_Begin(hc);
    HASH_Update(hc, (const unsigned char*)pInput, strlen(pInput));
    HASH_End(hc, hash, &len, sizeof(hash));
    HASH_Destroy(hc);

    char hash_str[SHA1_LENGTH*2 + 1];
    char *d = hash_str;
    unsigned char *s = hash;
    while (len)
    {
        *d++ = "0123456789abcdef"[*s >> 4];
        *d++ = "0123456789abcdef"[*s & 0xf];
        s++;
        len--;
    }
    *d = '\0';

    return hash_str;
}

static string concat_str_vector(char **strings)
{
    string result;
    while (*strings)
    {
        result += *strings++;
        if (*strings)
            result += ' ';
    }
    return result;
}

/* Returns status. See `man 2 wait` for status information. */
static int ExecVP(char **pArgs, uid_t uid, string& pOutput)
{
    int pipeout[2];
    pid_t child;

    xpipe(pipeout);
    child = fork();
    if (child == -1)
    {
        perror_msg_and_die("fork");
    }
    if (child == 0)
    {
        VERB1 log("Executing: %s", concat_str_vector(pArgs).c_str());
        close(pipeout[0]); /* read side of the pipe */
        xmove_fd(pipeout[1], STDOUT_FILENO);
        /* Make sure stdin is safely open to nothing */
        xmove_fd(xopen("/dev/null", O_RDONLY), STDIN_FILENO);
        /* Not a good idea, we won't see any error messages */
        /* close(STDERR_FILENO); */

        struct passwd* pw = getpwuid(uid);
        gid_t gid = pw ? pw->pw_gid : uid;
        setgroups(1, &gid);
        xsetregid(gid, gid);
        xsetreuid(uid, uid);
        setsid();

        /* Nuke everything which may make setlocale() switch to non-POSIX locale:
         * we need to avoid having gdb output in some obscure language.
         */
        unsetenv("LANG");
        unsetenv("LC_ALL");
        unsetenv("LC_COLLATE");
        unsetenv("LC_CTYPE");
        unsetenv("LC_MESSAGES");
        unsetenv("LC_MONETARY");
        unsetenv("LC_NUMERIC");
        unsetenv("LC_TIME");

        execvp(pArgs[0], pArgs);
        /* VERB1 since sometimes we expect errors here */
        VERB1 perror_msg("Can't execute '%s'", pArgs[0]);
        exit(1);
    }

    close(pipeout[1]); /* write side of the pipe */

    int r;
    char buff[1024];
    while ((r = read(pipeout[0], buff, sizeof(buff) - 1)) > 0)
    {
        buff[r] = '\0';
        pOutput += buff;
    }

    close(pipeout[0]);
    int status;
    wait(&status); /* prevent having zombie child process */

    return status;
}

enum LineRating
{
    // RATING              EXAMPLE
    MissingEverything = 0, // #0 0x0000dead in ?? ()
    MissingFunction   = 1, // #0 0x0000dead in ?? () from /usr/lib/libfoobar.so.4
    MissingLibrary    = 2, // #0 0x0000dead in foobar()
    MissingSourceFile = 3, // #0 0x0000dead in FooBar::FooBar () from /usr/lib/libfoobar.so.4
    Good              = 4, // #0 0x0000dead in FooBar::crash (this=0x0) at /home/user/foobar.cpp:204
    BestRating = Good,
};

static LineRating rate_line(const char *line)
{
#define FOUND(x) (strstr(line, x) != NULL)
    /* see the "enum LineRating" comments for possible combinations */
    if (FOUND(" at "))
        return Good;
    const char *function = strstr(line, " in ");
    if (function)
    {
        if (function[4] == '?') /* " in ??" does not count */
        {
            function = NULL;
        }
    }
    bool library = FOUND(" from ");
    if (function && library)
        return MissingSourceFile;
    if (function)
        return MissingLibrary;
    if (library)
        return MissingFunction;

    return MissingEverything;
#undef FOUND
}

/* returns number of "stars" to show */
static int rate_backtrace(const char *backtrace)
{
    int i, j, len;
    int multiplier = 0;
    int rating = 0;
    int best_possible_rating = 0;

    /* We look at the frames in reversed order, since:
     * - rate_line() checks starting from the first line of the frame
     * (note: it may need to look at more than one line!)
     * - we increase weight (multiplier) for every frame,
     *   so that topmost frames end up most important
     */
    len = 0;
    for (i = strlen(backtrace) - 1; i >= 0; i--)
    {
        if (backtrace[i] == '#') /* this separates frames from each other */
        {
            string s(backtrace + i + 1, len);
            for (j=0; j<len; j++) /* replace tabs with spaces */
                if (s[j] == '\t')
                    s[j] = ' ';
            multiplier++;
            rating += rate_line(s.c_str()) * multiplier;
            best_possible_rating += BestRating * multiplier;
            len = 0; /* starting new line */
        }
        else
        {
            len++;
        }
    }

    /* Bogus "backtrace" with zero frames? */
    if (best_possible_rating == 0)
        return 0;

    /* Returning number of "stars" to show */
    if (rating*10 >= best_possible_rating*8) /* >= 0.8 */
        return 4;
    if (rating*10 >= best_possible_rating*6)
        return 3;
    if (rating*10 >= best_possible_rating*4)
        return 2;
    if (rating*10 >= best_possible_rating*2)
        return 1;

    return 0;
}

static void GetBacktrace(const char *pDebugDumpDir,
                         const char *pDebugInfoDirs,
                         string& pBacktrace)
{
    update_client(_("Generating backtrace"));

    string UID;
    string executable;
    {
        CDebugDump dd;
        dd.Open(pDebugDumpDir);
        dd.LoadText(FILENAME_EXECUTABLE, executable);
        dd.LoadText(FILENAME_UID, UID);
    }

    // Workaround for
    // http://sourceware.org/bugzilla/show_bug.cgi?id=9622
    unsetenv("TERM");
    putenv((char*)"TERM=dumb");

    char *args[13];
    args[0] = (char*)"gdb";
    args[1] = (char*)"-batch";

    // when/if gdb supports it:
    // (https://bugzilla.redhat.com/show_bug.cgi?id=528668):
    args[2] = (char*)"-ex";
    string dfd = "set debug-file-directory /usr/lib/debug";
    const char *p = pDebugInfoDirs;
    while (1)
    {
        const char *colon_or_nul = strchrnul(p, ':');
        dfd += ':';
        dfd.append(p, colon_or_nul - p);
        dfd += "/usr/lib/debug";
        if (*colon_or_nul != ':')
            break;
        p = colon_or_nul + 1;
    }
    args[3] = (char*)dfd.c_str();

    /*
     * Unfortunately, "file BINARY_FILE" doesn't work well if BINARY_FILE
     * was deleted (as often happens during system updates):
     * gdb uses specified BINARY_FILE
     * even if it is completely unrelated to the coredump
     * See https://bugzilla.redhat.com/show_bug.cgi?id=525721
     */
    args[4] = (char*)"-ex";
    string file = ssprintf("file %s", executable.c_str());
    args[5] = (char*)file.c_str();

    args[6] = (char*)"-ex";
    string corefile = ssprintf("core-file %s/"FILENAME_COREDUMP, pDebugDumpDir);
    args[7] = (char*)corefile.c_str();

    args[8] = (char*)"-ex";
    args[9] = (char*)"thread apply all backtrace full";
    args[10] = (char*)"-ex";
    args[11] = (char*)"info sharedlib";
    args[12] = NULL;

    ExecVP(args, atoi(UID.c_str()), pBacktrace);
}

static void GetIndependentBuildIdPC(const char *unstrip_n_output,
                                    string& pIndependentBuildIdPC)
{
    // lines look like this:
    // 0x400000+0x209000 23c77451cf6adff77fc1f5ee2a01d75de6511dda@0x40024c - - [exe]
    // 0x400000+0x209000 ab3c8286aac6c043fd1bb1cc2a0b88ec29517d3e@0x40024c /bin/sleep /usr/lib/debug/bin/sleep.debug [exe]
    // 0x7fff313ff000+0x1000 389c7475e3d5401c55953a425a2042ef62c4c7df@0x7fff313ff2f8 . - linux-vdso.so.1
    const char *line = unstrip_n_output;
    while (*line)
    {
        const char *eol = strchrnul(line, '\n');
        const char *plus = (char*)memchr(line, '+', eol - line);
        if (plus)
        {
            while (++plus < eol && *plus != '@')
            {
                if (!isspace(*plus))
                {
                    pIndependentBuildIdPC += *plus;
                }
            }
        }
        if (*eol != '\n') break;
        line = eol + 1;
    }
}

static string run_unstrip_n(const char *pDebugDumpDir)
{
    string UID;
    {
        CDebugDump dd;
        dd.Open(pDebugDumpDir);
        dd.LoadText(FILENAME_UID, UID);
    }

    char* args[4];
    args[0] = (char*)"eu-unstrip";
    args[1] = xasprintf("--core=%s/"FILENAME_COREDUMP, pDebugDumpDir);
    args[2] = (char*)"-n";
    args[3] = NULL;

    string output;
    ExecVP(args, atoi(UID.c_str()), output);

    free(args[1]);

    return output;
}

/* Needs gdb feature from here: https://bugzilla.redhat.com/show_bug.cgi?id=528668
 * It is slated to be in F12/RHEL6.
 */
static void InstallDebugInfos(const char *pDebugDumpDir,
                              const char *debuginfo_dirs,
                              string& build_ids)
{
    update_client(_("Starting debuginfo installation"));

    int pipeout[2]; //TODO: can we use ExecVP?
    xpipe(pipeout);

    pid_t child = fork();
    if (child < 0)
    {
        /*close(pipeout[0]); - why bother */
        /*close(pipeout[1]); */
        perror_msg_and_die("fork");
    }
    if (child == 0)
    {
        close(pipeout[0]);
        xmove_fd(pipeout[1], STDOUT_FILENO);
        xmove_fd(xopen("/dev/null", O_RDONLY), STDIN_FILENO);
        /* Not a good idea, we won't see any error messages */
        /*close(STDERR_FILENO);*/

        setsid();

        char *coredump = xasprintf("%s/"FILENAME_COREDUMP, pDebugDumpDir);
        /* SELinux guys are not happy with /tmp, using /var/run/abrt */
        char *tempdir = xasprintf(LOCALSTATEDIR"/run/abrt/tmp-%u-%lu", (int)getpid(), (long)time(NULL));
        /* log() goes to stderr/syslog, it's ok to use it here */
        VERB1 log("Executing: %s %s %s %s", "abrt-debuginfo-install", coredump, tempdir, debuginfo_dirs);
        execlp("abrt-debuginfo-install", "abrt-debuginfo-install", coredump, tempdir, debuginfo_dirs, NULL);
        exit(1);
    }

    close(pipeout[1]);

    FILE *pipeout_fp = fdopen(pipeout[0], "r");
    if (pipeout_fp == NULL) /* never happens */
    {
        close(pipeout[0]);
        wait(NULL);
        return;
    }

    char buff[1024];
    while (fgets(buff, sizeof(buff), pipeout_fp))
    {
        int last = strlen(buff) - 1;
        if (last >= 0 && buff[last] == '\n')
            buff[last] = '\0';

        if (strncmp(buff, "MISSING:", 8) == 0)
        {
            build_ids += "Debuginfo absent: ";
            build_ids += buff + 8;
            build_ids += "\n";
            continue;
        }

        const char *p = buff;
        while (*p == ' ' || *p == '\t')
        {
            p++;
        }
        if (*p)
        {
            VERB1 log("%s", buff);
            update_client("%s", buff);
        }
    }

    fclose(pipeout_fp);
    wait(NULL);
}

static double get_dir_size(const char *dirname,
                           string *worst_file,
                           double *maxsz)
{
    DIR *dp = opendir(dirname);
    if (dp == NULL)
        return 0;

    struct dirent *ep;
    struct stat stats;
    double size = 0;
    while ((ep = readdir(dp)) != NULL)
    {
        if (dot_or_dotdot(ep->d_name))
            continue;
        string dname = concat_path_file(dirname, ep->d_name);
        if (lstat(dname.c_str(), &stats) != 0)
            continue;
        if (S_ISDIR(stats.st_mode))
        {
            double sz = get_dir_size(dname.c_str(), worst_file, maxsz);
            size += sz;
        }
        else if (S_ISREG(stats.st_mode))
        {
            double sz = stats.st_size;
            size += sz;

            if (worst_file)
            {
                /* Calculate "weighted" size and age
                 * w = sz_kbytes * age_mins */
                sz /= 1024;
                long age = (time(NULL) - stats.st_mtime) / 60;
                if (age > 0)
                    sz *= age;

                if (sz > *maxsz)
                {
                    *maxsz = sz;
                    *worst_file = dname;
                }
            }
        }
    }
    closedir(dp);
    return size;
}

static void trim_debuginfo_cache(unsigned max_mb)
{
    while (1)
    {
        string worst_file;
        double maxsz = 0;
        double cache_sz = get_dir_size(DEBUGINFO_CACHE_DIR, &worst_file, &maxsz);
        if (cache_sz / (1024 * 1024) < max_mb)
            break;
        VERB1 log("%s is %.0f bytes (over %u MB), deleting '%s'",
                DEBUGINFO_CACHE_DIR, cache_sz, max_mb, worst_file.c_str());
        if (unlink(worst_file.c_str()) != 0)
            perror_msg("Can't unlink '%s'", worst_file.c_str());
    }
}

string CAnalyzerCCpp::GetLocalUUID(const char *pDebugDumpDir)
{
    log(_("Getting local universal unique identification..."));

    string executable;
    string package;
    {
        CDebugDump dd;
        dd.Open(pDebugDumpDir);
        dd.LoadText(FILENAME_EXECUTABLE, executable);
        dd.LoadText(FILENAME_PACKAGE, package);
    }

    string unstrip_n_output = run_unstrip_n(pDebugDumpDir);
    string independentBuildIdPC;
    GetIndependentBuildIdPC(unstrip_n_output.c_str(), independentBuildIdPC);
    return CreateHash((package + executable + independentBuildIdPC).c_str());
}

string CAnalyzerCCpp::GetGlobalUUID(const char *pDebugDumpDir)
{
    log(_("Getting global universal unique identification..."));

    string backtrace_path = (string)pDebugDumpDir + "/" + FILENAME_BACKTRACE;
    string executable;
    string package;
    string uid_str;
    {
        CDebugDump dd;
        dd.Open(pDebugDumpDir);
        dd.LoadText(FILENAME_EXECUTABLE, executable);
        dd.LoadText(FILENAME_PACKAGE, package);
        dd.LoadText(FILENAME_UID, uid_str);
    }

    /* Run abrt-backtrace to get independent backtrace suitable
       to UUID calculation. */
    char *args[6];
    args[0] = (char*)"abrt-backtrace";
    args[1] = (char*)"--single-thread";
    args[2] = (char*)"--remove-exit-handlers";
    args[3] = (char*)"--frame-depth=5";
    args[4] = (char*)backtrace_path.c_str();
    args[5] = NULL;

    int pipeout[2];
    xpipe(pipeout); /* stdout of abrt-backtrace */
    pid_t child = fork();
    if (child == -1)
        perror_msg_and_die("fork");
    if (child == 0)
    {
        VERB1 log("Executing: %s", concat_str_vector(args).c_str());

        xmove_fd(pipeout[1], STDOUT_FILENO);
        close(pipeout[0]); /* read side of the pipe */

        /* abrt-backtrace is executed under the user's uid and gid. */
        uid_t uid = atoi(uid_str.c_str());
        struct passwd* pw = getpwuid(uid);
        gid_t gid = pw ? pw->pw_gid : uid;
        setgroups(1, &gid);
        xsetregid(gid, gid);
        xsetreuid(uid, uid);

        execvp(args[0], args);
        VERB1 perror_msg("Can't execute '%s'", args[0]);
        exit(1);
    }

    close(pipeout[1]); /* write side of the pipe */

    /* Read the result from abrt-backtrace. */
    int r;
    char buff[1024];
    string independent_backtrace;
    while ((r = read(pipeout[0], buff, sizeof(buff) - 1)) > 0)
    {
        buff[r] = '\0';
        independent_backtrace += buff;
    }
    close(pipeout[0]);

    /* Wait until it ends, and check the exit status. */
    int status;
    wait(&status); /* prevent having zombie child process */
    if (!WIFEXITED(status))
    {
        perror_msg_and_die("abrt-backtrace not executed properly, "
                           "status: %x", status);
    }
    int exit_status = WEXITSTATUS(status);
    if (exit_status > 0 && exit_status <= EX__MAX)
    {
        error_msg_and_die("abrt-backtrace run failed, exit value: %d",
                          exit_status);
    }

    /*VERB1 log("abrt-backtrace result: %s", independent_backtrace.c_str());*/

    string hash_base = package + executable + independent_backtrace;
    return CreateHash(hash_base.c_str());
}

static bool DebuginfoCheckPolkit(int uid)
{
    int child_pid = fork();
    if (child_pid < 0)
    {
        perror_msg_and_die("fork");
    }
    if (child_pid == 0)
    {
        //child
        xsetreuid(uid, uid);
        PolkitResult result = polkit_check_authorization(getpid(),
                 "org.fedoraproject.abrt.install-debuginfos");
        exit(result != PolkitYes); //exit 1 (failure) if not allowed
    }

    //parent
    int status;
    if (waitpid(child_pid, &status, 0) > 0 && WEXITSTATUS(status) == 0)
    {
        return true; //authorization OK
    }
    log("UID %d is not authorized to install debuginfos", uid);
    return false;
}

void CAnalyzerCCpp::CreateReport(const char *pDebugDumpDir, int force)
{
    string package;
    string backtrace;
    string UID;

    CDebugDump dd;
    dd.Open(pDebugDumpDir);

    if (!force)
    {
        bool bt_exists = dd.Exist(FILENAME_BACKTRACE);
        if (bt_exists)
        {
            return; /* backtrace already exists */
        }
    }

    dd.LoadText(FILENAME_PACKAGE, package);
    dd.LoadText(FILENAME_UID, UID);
    dd.Close(); /* do not keep dir locked longer than needed */

    string build_ids;
    if (m_bInstallDebugInfo && DebuginfoCheckPolkit(atoi(UID.c_str())))
    {
        if (m_nDebugInfoCacheMB > 0)
        {
            trim_debuginfo_cache(m_nDebugInfoCacheMB);
        }
        InstallDebugInfos(pDebugDumpDir, m_sDebugInfoDirs.c_str(), build_ids);
    }
    else
    {
        VERB1 log(_("Skipping debuginfo installation"));
    }

    GetBacktrace(pDebugDumpDir, m_sDebugInfoDirs.c_str(), backtrace);

    dd.Open(pDebugDumpDir);
    dd.SaveText(FILENAME_BACKTRACE, (backtrace + build_ids).c_str());
    if (m_bMemoryMap)
    {
        dd.SaveText(FILENAME_MEMORYMAP, "memory map of the crashed C/C++ application, not implemented yet");
    }
    dd.SaveText(FILENAME_RATING, to_string(rate_backtrace(backtrace.c_str())).c_str());
    dd.Close();
}

void CAnalyzerCCpp::Init()
{
    ifstream fInCorePattern;
    fInCorePattern.open(CORE_PATTERN_IFACE);
    if (fInCorePattern.is_open())
    {
        getline(fInCorePattern, m_sOldCorePattern);
        fInCorePattern.close();
    }
    if (m_sOldCorePattern[0] == '|')
    {
        if (m_sOldCorePattern == CORE_PATTERN)
        {
            log("warning: %s already contains %s, "
                "did abrt daemon crash recently?",
                CORE_PATTERN_IFACE, CORE_PATTERN);
            /* There is no point in "restoring" CORE_PATTERN_IFACE
             * to CORE_PATTERN on exit. Will restore to a default value:
             */
            m_sOldCorePattern = "core";
        } else {
            log("warning: %s was already set to run a crash analyser (%s), "
                "abrt may interfere with it",
                CORE_PATTERN_IFACE, CORE_PATTERN);
        }
    }

    ofstream fOutCorePattern;
    fOutCorePattern.open(CORE_PATTERN_IFACE);
    if (fOutCorePattern.is_open())
    {
        fOutCorePattern << CORE_PATTERN << endl;
        fOutCorePattern.close();
    }
}

void CAnalyzerCCpp::DeInit()
{
    ofstream fOutCorePattern;
    fOutCorePattern.open(CORE_PATTERN_IFACE);
    if (fOutCorePattern.is_open())
    {
        fOutCorePattern << m_sOldCorePattern << endl;
        fOutCorePattern.close();
    }
}

void CAnalyzerCCpp::SetSettings(const map_plugin_settings_t& pSettings)
{
    m_pSettings = pSettings;

    map_plugin_settings_t::const_iterator end = pSettings.end();
    map_plugin_settings_t::const_iterator it;
    it = pSettings.find("MemoryMap");
    if (it != end)
    {
        m_bMemoryMap = string_to_bool(it->second.c_str());
    }
    it = pSettings.find("DebugInfo");
    if (it != end)
    {
        m_sDebugInfo = it->second;
    }
    it = pSettings.find("DebugInfoCacheMB");
    if (it != end)
    {
        m_nDebugInfoCacheMB = atoi(it->second.c_str());
    }
    it = pSettings.find("InstallDebugInfo");
    if (it == end) //compat, remove after 0.0.11
        it = pSettings.find("InstallDebuginfo");
    if (it != end)
    {
        m_bInstallDebugInfo = string_to_bool(it->second.c_str());
    }
    m_sDebugInfoDirs = DEBUGINFO_CACHE_DIR;
    it = pSettings.find("ReadonlyLocalDebugInfoDirs");
    if (it != end)
    {
        m_sDebugInfoDirs += ':';
        m_sDebugInfoDirs += it->second;
    }
}

//ok to delete?
//const map_plugin_settings_t& CAnalyzerCCpp::GetSettings()
//{
//    m_pSettings["MemoryMap"] = m_bMemoryMap ? "yes" : "no";
//    m_pSettings["DebugInfo"] = m_sDebugInfo;
//    m_pSettings["DebugInfoCacheMB"] = to_string(m_nDebugInfoCacheMB);
//    m_pSettings["InstallDebugInfo"] = m_bInstallDebugInfo ? "yes" : "no";
//
//    return m_pSettings;
//}

PLUGIN_INFO(ANALYZER,
            CAnalyzerCCpp,
            "CCpp",
            "0.0.1",
            "Analyzes crashes in C/C++ programs",
            "zprikryl@redhat.com",
            "https://fedorahosted.org/abrt/wiki",
            "");