path: root/src/plugins/CCpp.cpp

/*
    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 <set>
#include "abrtlib.h"
#include "CCpp.h"
#include "abrt_exception.h"
#include "comm_layer_inner.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 %c"
#define CORE_PIPE_LIMIT_IFACE   "/proc/sys/kernel/core_pipe_limit"
/* core_pipe_limit specifies how many dump_helpers might run at the same time
 * 0 - means unlimited, but it's not guaranteed that /proc/<pid> of crashing
 * process will be available for dump_helper
 * 4 - means that 4 dump_helpers can run at the same time (the rest will also
 * run, but they will fail to read /proc/<pid>)
 * This should be enough for ABRT, we can miss some crashes, but what are
 * the odds that more processes crash at the same time?
 * The value of 4 has been recommended by nhorman.
 */
#define CORE_PIPE_LIMIT         "4"

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

CAnalyzerCCpp::CAnalyzerCCpp() :
    m_bBacktrace(true),
    m_bBacktraceRemotes(false),
    m_bMemoryMap(false),
    m_bInstallDebugInfo(true),
    m_nDebugInfoCacheMB(4000),
    m_nGdbTimeoutSec(60)
{}

/*
 this is just a workaround until kernel changes it's behavior
 when handling pipes in core_pattern
*/
#ifdef HOSTILE_KERNEL
#define CORE_SIZE_PATTERN "Max core file size=1:unlimited"
static int isdigit_str(char *str)
{
    do {
        if (*str < '0' || *str > '9')
            return 0;
    } while (*++str);
    return 1;
}

static int set_limits()
{
    DIR *dir = opendir("/proc");
    if (!dir) {
        /* this shouldn't fail, but to be safe.. */
        return 1;
    }

    struct dirent *ent;
    while ((ent = readdir(dir)) != NULL) {
        if (!isdigit_str(ent->d_name))
            continue;

        char limits_name[sizeof("/proc/%s/limits") + sizeof(long)*3];
        snprintf(limits_name, sizeof(limits_name), "/proc/%s/limits", ent->d_name);
        FILE *limits_fp = fopen(limits_name, "r");
        if (!limits_fp) {
            break;
        }

        char line[128];
        char *ulimit_c = NULL;
        while (1) {
            if (fgets(line, sizeof(line)-1, limits_fp) == NULL)
                break;
            if (strncmp(line, "Max core file size", sizeof("Max core file size")-1) == 0) {
                ulimit_c = skip_whitespace(line + sizeof("Max core file size")-1);
                skip_non_whitespace(ulimit_c)[0] = '\0';
                break;
            }
        }
        fclose(limits_fp);
        if (!ulimit_c || ulimit_c[0] != '0' || ulimit_c[1] != '\0') {
            /*process has nonzero ulimit -c, so need to modify it*/
            continue;
        }
        /* echo -n 'Max core file size=1:unlimited' >/proc/PID/limits */
        int fd = open(limits_name, O_WRONLY);
        if (fd >= 0) {
            errno = 0;
            /*full_*/
            ssize_t n = write(fd, CORE_SIZE_PATTERN, sizeof(CORE_SIZE_PATTERN)-1);
            if (n < sizeof(CORE_SIZE_PATTERN)-1)
                log("warning: can't write core_size limit to: %s", limits_name);
            close(fd);
        }
        else
        {
            log("warning: can't open %s for writing", limits_name);
        }
    }
    closedir(dir);
    return 0;
}
#endif /* HOSTILE_KERNEL */

void CAnalyzerCCpp::Init()
{
    FILE *fp = fopen(CORE_PATTERN_IFACE, "r");
    if (fp)
    {
        char line[PATH_MAX];
        if (fgets(line, sizeof(line), fp))
            m_sOldCorePattern = line;
        fclose(fp);
    }
    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);
        }
    }
#ifdef HOSTILE_KERNEL
    if (set_limits() != 0)
        log("warning: failed to set core_size limit, ABRT won't detect crashes in"
            "compiled apps");
#endif

    fp = fopen(CORE_PATTERN_IFACE, "w");
    if (fp)
    {
        fputs(CORE_PATTERN, fp);
        fclose(fp);
    }

    /* read the core_pipe_limit and change it if it's == 0
       otherwise the abrt-hook-ccpp won't be able to read /proc/<pid>
       of the crashing process
    */
    fp = fopen(CORE_PIPE_LIMIT_IFACE, "r");
    if (fp)
    {
        /* we care only about the first char, if it's
         * not '0' then we don't have to change it,
         * because it means that it's already != 0
         */
        char pipe_limit[2];
        if (!fgets(pipe_limit, sizeof(pipe_limit), fp))
            pipe_limit[0] = '1'; /* not 0 */
        fclose(fp);
        if (pipe_limit[0] == '0')
        {
            fp = fopen(CORE_PIPE_LIMIT_IFACE, "w");
            if (fp)
            {
                fputs(CORE_PIPE_LIMIT, fp);
                fclose(fp);
            }
            else
            {
                log("warning: failed to set core_pipe_limit, ABRT won't detect"
                    "crashes in compiled apps if kernel > 2.6.31");
            }
        }
    }
}

void CAnalyzerCCpp::DeInit()
{
    /* no need to restore the core_pipe_limit, because it's only used
       when there is s pipe in core_pattern
    */
    FILE *fp = fopen(CORE_PATTERN_IFACE, "w");
    if (fp)
    {
        fputs(m_sOldCorePattern.c_str(), fp);
        fclose(fp);
    }
}

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("Backtrace");
    if (it != end)
    {
        m_bBacktrace = string_to_bool(it->second.c_str());
    }
    it = pSettings.find("BacktraceRemotes");
    if (it != end)
    {
        m_bBacktraceRemotes = string_to_bool(it->second.c_str());
    }
    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 = xatou(it->second.c_str());
    }
    it = pSettings.find("GdbTimeoutSec");
    if (it != end)
    {
        m_nGdbTimeoutSec = xatoi_u(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",
            "");