pal.unix.cpp

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#include "pal.h"
#include "utils.h"
#include "trace.h"

#include <cassert>
#include <dlfcn.h>
#include <dirent.h>
#include <pwd.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <ctime>

#if defined(__APPLE__)
#include <mach-o/dyld.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#endif

#if defined(__LINUX__)
#define symlinkEntrypointExecutable "/proc/self/exe"
#elif !defined(__APPLE__)
#define symlinkEntrypointExecutable "/proc/curproc/exe"
#endif

pal::string_t pal::to_string(int value) { return std::to_string(value); }

pal::string_t pal::to_lower(const pal::string_t& in)
{
    pal::string_t ret = in;
    std::transform(ret.begin(), ret.end(), ret.begin(), ::tolower);
    return ret;
}

pal::string_t pal::get_timestamp()
{
    std::time_t t = std::time(nullptr);
    const std::size_t elems = 100;
    char_t buf[elems];
    std::strftime(buf, elems, _X("%c %Z"), std::gmtime(&t));

    return pal::string_t(buf);
}

bool pal::touch_file(const pal::string_t& path)
{
    int fd = open(path.c_str(), (O_CREAT | O_EXCL), (S_IRUSR | S_IRGRP | S_IROTH));
    if (fd == -1)
    {
        trace::warning(_X("open(%s) failed in %s"), path.c_str(), _STRINGIFY(__FUNCTION__));
        return false;
    }
    (void) close(fd);
    return true;
}

void* pal::map_file_readonly(const pal::string_t& path, size_t& length)
{
    int fd = open(path.c_str(), O_RDONLY, (S_IRUSR | S_IRGRP | S_IROTH));
    if (fd == -1)
    {
        trace::warning(_X("Failed to map file. open(%s) failed with error %d"), path.c_str(), errno);
        return nullptr;
    }

    struct stat buf;
    if (fstat(fd, &buf) != 0)
    {
        trace::warning(_X("Failed to map file. fstat(%s) failed with error %d"), path.c_str(), errno);
        close(fd);
        return nullptr;
    }

    length = buf.st_size;
    void* address = mmap(nullptr, length, PROT_READ, MAP_SHARED, fd, 0);

    if(address == nullptr)
    {
        trace::warning(_X("Failed to map file. mmap(%s) failed with error %d"), path.c_str(), errno);
        close(fd);
        return nullptr;
    }

    close(fd);
    return address;
}

bool pal::getcwd(pal::string_t* recv)
{
    recv->clear();
    pal::char_t* buf = ::getcwd(nullptr, 0);
    if (buf == nullptr)
    {
        if (errno == ENOENT)
        {
            return false;
        }

        trace::error(_X("getcwd() failed: %s"), strerror(errno));
        return false;
    }
    recv->assign(buf);
    ::free(buf);
    return true;
}

namespace
{
    bool get_loaded_library_from_proc_maps(const pal::char_t *library_name, pal::dll_t *dll, pal::string_t *path)
    {
        char *line = nullptr;
        size_t lineLen = 0;
        ssize_t read;
        FILE *file = pal::file_open(_X("/proc/self/maps"), _X("r"));
        if (file == nullptr)
            return false;

        // Read maps file line by line to check fo the library
        bool found = false;
        pal::string_t path_local;
        while ((read = getline(&line, &lineLen, file)) != -1)
        {
            char buf[PATH_MAX];
            if (sscanf(line, "%*p-%*p %*[-rwxsp] %*p %*[:0-9a-f] %*d %s\n", buf) == 1)
            {
                path_local = buf;
                size_t pos = path_local.rfind(DIR_SEPARATOR);
                if (pos == std::string::npos)
                    continue;

                pos = path_local.find(library_name, pos);
                if (pos != std::string::npos)
                {
                    found = true;
                    break;
                }
            }
        }

        fclose(file);
        if (!found)
            return false;

        pal::dll_t dll_maybe = dlopen(path_local.c_str(), RTLD_LAZY | RTLD_NOLOAD);
        if (dll_maybe == nullptr)
            return false;

        *dll = dll_maybe;
        path->assign(path_local);
        return true;
    }
}

bool pal::get_loaded_library(
    const char_t *library_name,
    const char *symbol_name,
    /*out*/ dll_t *dll,
    /*out*/ pal::string_t *path)
{
    pal::string_t library_name_local;
#if defined(__APPLE__)
    if (!pal::is_path_rooted(library_name))
        library_name_local.append("@rpath/");
#endif
    library_name_local.append(library_name);

    dll_t dll_maybe = dlopen(library_name_local.c_str(), RTLD_LAZY | RTLD_NOLOAD);
    if (dll_maybe == nullptr)
    {
        if (pal::is_path_rooted(library_name))
            return false;

        // dlopen on some systems only finds loaded libraries when given the full path
        // Check proc maps as a fallback
        return get_loaded_library_from_proc_maps(library_name, dll, path);
    }

    // Not all systems support getting the path from just the handle (e.g. dlinfo),
    // so we rely on the caller passing in a symbol name so that we get (any) address
    // in the library
    assert(symbol_name != nullptr);
    pal::proc_t proc = pal::get_symbol(dll_maybe, symbol_name);
    Dl_info info;
    if (dladdr(proc, &info) == 0)
        return false;

    *dll = dll_maybe;
    path->assign(info.dli_fname);
    return true;
}

bool pal::load_library(const string_t* path, dll_t* dll)
{
    *dll = dlopen(path->c_str(), RTLD_LAZY);
    if (*dll == nullptr)
    {
        trace::error(_X("Failed to load %s, error: %s"), path, dlerror());
        return false;
    }
    return true;
}

pal::proc_t pal::get_symbol(dll_t library, const char* name)
{
    auto result = dlsym(library, name);
    if (result == nullptr)
    {
        trace::info(_X("Probed for and did not find library symbol %s, error: %s"), name, dlerror());
    }

    return result;
}

void pal::unload_library(dll_t library)
{
    if (dlclose(library) != 0)
    {
        trace::warning(_X("Failed to unload library, error: %s"), dlerror());
    }
}

int pal::xtoi(const char_t* input)
{
    return atoi(input);
}

bool pal::is_path_rooted(const pal::string_t& path)
{
    return path.front() == '/';
}

bool pal::get_default_breadcrumb_store(string_t* recv)
{
    recv->clear();
    pal::string_t ext;
    if (pal::getenv(_X("CORE_BREADCRUMBS"), &ext) && pal::realpath(&ext))
    {
        // We should have the path in ext.
        trace::info(_X("Realpath CORE_BREADCRUMBS [%s]"), ext.c_str());
    }

    if (!pal::directory_exists(ext))
    {
        trace::info(_X("Directory core breadcrumbs [%s] was not specified or found"), ext.c_str());
        ext.clear();
        append_path(&ext, _X("opt"));
        append_path(&ext, _X("corebreadcrumbs"));
        if (!pal::directory_exists(ext))
        {
            trace::info(_X("Fallback directory core breadcrumbs at [%s] was not found"), ext.c_str());
            return false;
        }
    }

    if (access(ext.c_str(), (R_OK | W_OK)) != 0)
    {
        trace::info(_X("Breadcrumb store [%s] is not ACL-ed with rw-"), ext.c_str());
    }

    recv->assign(ext);
    return true;
}

bool pal::get_default_servicing_directory(string_t* recv)
{
    recv->clear();
    pal::string_t ext;
    if (pal::getenv(_X("CORE_SERVICING"), &ext) && pal::realpath(&ext))
    {
        // We should have the path in ext.
        trace::info(_X("Realpath CORE_SERVICING [%s]"), ext.c_str());
    }

    if (!pal::directory_exists(ext))
    {
        trace::info(_X("Directory core servicing at [%s] was not specified or found"), ext.c_str());
        ext.clear();
        append_path(&ext, _X("opt"));
        append_path(&ext, _X("coreservicing"));
        if (!pal::directory_exists(ext))
        {
            trace::info(_X("Fallback directory core servicing at [%s] was not found"), ext.c_str());
            return false;
        }
    }

    if (access(ext.c_str(), R_OK) != 0)
    {
        trace::info(_X("Directory core servicing at [%s] was not ACL-ed properly"), ext.c_str());
    }

    recv->assign(ext);
    trace::info(_X("Using core servicing at [%s]"), ext.c_str());
    return true;
}

bool is_read_write_able_directory(pal::string_t& dir)
{
    return pal::realpath(&dir) &&
           (access(dir.c_str(), R_OK | W_OK | X_OK) == 0);
}

bool pal::get_temp_directory(pal::string_t& tmp_dir)
{
    // First, check for the POSIX standard environment variable
    if (pal::getenv(_X("TMPDIR"), &tmp_dir))
    {
        return is_read_write_able_directory(tmp_dir);
    }

    // On non-compliant systems (ex: Ubuntu) try /var/tmp or /tmp directories.
    // /var/tmp is prefered since its contents are expected to survive across
    // machine reboot.
    pal::string_t _var_tmp = _X("/var/tmp/");
    if (is_read_write_able_directory(_var_tmp))
    {
        tmp_dir.assign(_var_tmp);
        return true;
    }

    pal::string_t _tmp = _X("/tmp/");
    if (is_read_write_able_directory(_tmp))
    {
        tmp_dir.assign(_tmp);
        return true;
    }

    return false;
}

bool pal::get_global_dotnet_dirs(std::vector<pal::string_t>* recv)
{
    // No support for global directories in Unix.
    return false;
}

bool pal::get_dotnet_self_registered_config_location(pal::string_t* recv)
{
    *recv = _X("/etc/dotnet/install_location");

    //  ***Used only for testing***
    pal::string_t environment_install_location_override;
    if (test_only_getenv(_X("_DOTNET_TEST_INSTALL_LOCATION_FILE_PATH"), &environment_install_location_override))
    {
        *recv = environment_install_location_override;
    }

    return true;
}

bool pal::get_dotnet_self_registered_dir(pal::string_t* recv)
{
    recv->clear();

    //  ***Used only for testing***
    pal::string_t environment_override;
    if (test_only_getenv(_X("_DOTNET_TEST_GLOBALLY_REGISTERED_PATH"), &environment_override))
    {
        recv->assign(environment_override);
        return true;
    }
    //  ***************************

    pal::string_t install_location_file_path;
    if (!get_dotnet_self_registered_config_location(&install_location_file_path))
    {
        return false;
    }
    //  ***************************

    trace::verbose(_X("Looking for install_location file in '%s'."), install_location_file_path.c_str());
    FILE* install_location_file = pal::file_open(install_location_file_path, "r");
    if (install_location_file == nullptr)
    {
        trace::verbose(_X("The install_location file failed to open."));
        return false;
    }

    bool result = false;

    char buf[PATH_MAX];
    char* install_location = fgets(buf, sizeof(buf), install_location_file);
    if (install_location != nullptr)
    {
        size_t len = pal::strlen(install_location);

        // fgets includes the newline character in the string - so remove it.
        if (len > 0 && len < PATH_MAX && install_location[len - 1] == '\n')
        {
            install_location[len - 1] = '\0';
        }

        trace::verbose(_X("Using install location '%s'."), install_location);
        *recv = install_location;
        result = true;
    }
    else
    {
        trace::verbose(_X("The install_location file first line could not be read."));
    }

    fclose(install_location_file);
    return result;
}

bool pal::get_default_installation_dir(pal::string_t* recv)
{
    //  ***Used only for testing***
    pal::string_t environmentOverride;
    if (test_only_getenv(_X("_DOTNET_TEST_DEFAULT_INSTALL_PATH"), &environmentOverride))
    {
        recv->assign(environmentOverride);
        return true;
    }
    //  ***************************

#if defined(__APPLE__)
     recv->assign(_X("/usr/local/share/dotnet"));
#else
     recv->assign(_X("/usr/share/dotnet"));
#endif
     return true;
}

pal::string_t trim_quotes(pal::string_t stringToCleanup)
{
    pal::char_t quote_array[2] = {'\"', '\''};
    for(size_t index = 0; index < sizeof(quote_array)/sizeof(quote_array[0]); index++)
    {
        size_t pos = stringToCleanup.find(quote_array[index]);
        while(pos != std::string::npos)
        {
            stringToCleanup = stringToCleanup.erase(pos, 1);
            pos = stringToCleanup.find(quote_array[index]);
        }
    }

    return stringToCleanup;
}

#if defined(__APPLE__)
pal::string_t pal::get_current_os_rid_platform()
{
    pal::string_t ridOS;

    char str[256];

    // There is no good way to get the visible version of OSX (i.e. something like 10.x.y) as
    // certain APIs work till 10.9 and have been deprecated and others require linking against
    // UI frameworks to get the data.
    //
    // We will, instead, use kern.osrelease and use its major version number
    // as a means to formulate the OSX 10.X RID.
    //
    // Needless to say, this will need to be updated if OSX RID were to become 11.* ever.
    size_t size = sizeof(str);
    int ret = sysctlbyname("kern.osrelease", str, &size, nullptr, 0);
    if (ret == 0)
    {
        std::string release(str, size);
        size_t pos = release.find('.');
        if (pos != std::string::npos)
        {
            // Extract the major version and subtract 4 from it
            // to get the Minor version used in OSX versioning scheme.
            // That is, given a version 10.X.Y, we will get X below.
            int minorVersion = stoi(release.substr(0, pos)) - 4;
            if (minorVersion < 10)
            {
                // On OSX, our minimum supported RID is 10.12.
                minorVersion = 12;
            }

            ridOS.append(_X("osx.10."));
            ridOS.append(pal::to_string(minorVersion));
        }
    }

    return ridOS;
}
#elif defined(__FreeBSD__)
// On FreeBSD get major verion. Minors should be compatible
pal::string_t pal::get_current_os_rid_platform()
{
    pal::string_t ridOS;

    char str[256];

    size_t size = sizeof(str);
    int ret = sysctlbyname("kern.osrelease", str, &size, NULL, 0);
    if (ret == 0)
    {
        char *pos = strchr(str,'.');
        if (pos)
        {
            *pos = '\0';
        }
        ridOS.append(_X("freebsd."));
        ridOS.append(str);
    }

    return ridOS;
}
#else
// For some distros, we don't want to use the full version from VERSION_ID. One example is
// Red Hat Enterprise Linux, which includes a minor version in their VERSION_ID but minor
// versions are backwards compatable.
//
// In this case, we'll normalized RIDs like 'rhel.7.2' and 'rhel.7.3' to a generic
// 'rhel.7'. This brings RHEL in line with other distros like CentOS or Debian which
// don't put minor version numbers in their VERSION_ID fields because all minor versions
// are backwards compatible.
static
pal::string_t normalize_linux_rid(pal::string_t rid)
{
    pal::string_t rhelPrefix(_X("rhel."));
    pal::string_t alpinePrefix(_X("alpine."));
    size_t lastVersionSeparatorIndex = std::string::npos;

    if (rid.compare(0, rhelPrefix.length(), rhelPrefix) == 0)
    {
        lastVersionSeparatorIndex = rid.find(_X("."), rhelPrefix.length());
    }
    else if (rid.compare(0, alpinePrefix.length(), alpinePrefix) == 0)
    {
        size_t secondVersionSeparatorIndex = rid.find(_X("."), alpinePrefix.length());
        if (secondVersionSeparatorIndex != std::string::npos)
        {
            lastVersionSeparatorIndex = rid.find(_X("."), secondVersionSeparatorIndex + 1);
        }
    }

    if (lastVersionSeparatorIndex != std::string::npos)
    {
        rid.erase(lastVersionSeparatorIndex, rid.length() - lastVersionSeparatorIndex);
    }

    return rid;
}

pal::string_t pal::get_current_os_rid_platform()
{
    pal::string_t ridOS;
    pal::string_t versionFile(_X("/etc/os-release"));

    if (pal::file_exists(versionFile))
    {
        // Read the file to get ID and VERSION_ID data that will be used
        // to construct the RID.
        std::fstream fsVersionFile;

        fsVersionFile.open(versionFile, std::fstream::in);

        // Proceed only if we were able to open the file
        if (fsVersionFile.good())
        {
            pal::string_t line;
            pal::string_t strID(_X("ID="));
            pal::string_t valID;
            pal::string_t strVersionID(_X("VERSION_ID="));
            pal::string_t valVersionID;

            bool fFoundID = false, fFoundVersion = false;

            // Read the first line
            std::getline(fsVersionFile, line);

            // Loop until we are at the end of file
            while (!fsVersionFile.eof())
            {
                // Look for ID if we have not found it already
                if (!fFoundID)
                {
                    size_t pos = line.find(strID);
                    if ((pos != std::string::npos) && (pos == 0))
                    {
                        valID.append(line.substr(3));
                        fFoundID = true;
                    }
                }

                // Look for VersionID if we have not found it already
                if (!fFoundVersion)
                {
                    size_t pos = line.find(strVersionID);
                    if ((pos != std::string::npos) && (pos == 0))
                    {
                        valVersionID.append(line.substr(11));
                        fFoundVersion = true;
                    }
                }

                if (fFoundID && fFoundVersion)
                {
                    // We have everything we need to form the RID - break out of the loop.
                    break;
                }

                // Read the next line
                std::getline(fsVersionFile, line);
            }

            // Close the file now that we are done with it.
            fsVersionFile.close();

            if (fFoundID)
            {
                ridOS.append(valID);
            }

            if (fFoundVersion)
            {
                ridOS.append(_X("."));
                ridOS.append(valVersionID);
            }

            if (fFoundID || fFoundVersion)
            {
                // Remove any double-quotes
                ridOS = trim_quotes(ridOS);
            }
        }
    }

    return normalize_linux_rid(ridOS);
}
#endif

#if defined(__APPLE__)
bool pal::get_own_executable_path(pal::string_t* recv)
{
    uint32_t path_length = 0;
    if (_NSGetExecutablePath(nullptr, &path_length) == -1)
    {
        char path_buf[path_length];
        if (_NSGetExecutablePath(path_buf, &path_length) == 0)
        {
            recv->assign(path_buf);
            return true;
        }
    }
    return false;
}
#elif defined(__FreeBSD__)
bool pal::get_own_executable_path(pal::string_t* recv)
{
    int mib[4];
    mib[0] = CTL_KERN;
    mib[1] = KERN_PROC;
    mib[2] = KERN_PROC_PATHNAME;
    mib[3] = -1;
    char buf[PATH_MAX];
    size_t cb = sizeof(buf);
    int error_code = 0;
    error_code = sysctl(mib, 4, buf, &cb, NULL, 0);
    if (error_code == 0)
    {
        recv->assign(buf);
        return true;
    }

    // ENOMEM
    if (error_code == ENOMEM)
    {
        size_t len = sysctl(mib, 4, NULL, NULL, NULL, 0);
        std::unique_ptr<char[]> buffer (new (std::nothrow) char[len]);

        if (buffer == NULL)
        {
            return false;
        }

        error_code = sysctl(mib, 4, buffer.get(), &len, NULL, 0);
        if (error_code == 0)
        {
            recv->assign(buffer.get());
            return true;
        }
    }
    return false;
}
#else
bool pal::get_own_executable_path(pal::string_t* recv)
{
    // Just return the symlink to the exe from /proc
    // We'll call realpath on it later
    recv->assign(symlinkEntrypointExecutable);
    return true;
}
#endif

bool pal::get_own_module_path(string_t* recv)
{
    Dl_info info;
    if (dladdr((void *)&pal::get_own_module_path, &info) == 0)
        return false;

    recv->assign(info.dli_fname);
    return true;
}

bool pal::get_module_path(dll_t module, string_t* recv)
{
    return false;
}

bool pal::get_current_module(dll_t *mod)
{
    return false;
}

// Returns true only if an env variable can be read successfully to be non-empty.
bool pal::getenv(const pal::char_t* name, pal::string_t* recv)
{
    recv->clear();

    auto result = ::getenv(name);
    if (result != nullptr)
    {
        recv->assign(result);
    }

    return (recv->length() > 0);
}

bool pal::realpath(pal::string_t* path, bool skip_error_logging)
{
    auto resolved = ::realpath(path->c_str(), nullptr);
    if (resolved == nullptr)
    {
        if (errno == ENOENT)
        {
            return false;
        }

        if (!skip_error_logging)
        {
            trace::error(_X("realpath(%s) failed: %s"), path->c_str(), strerror(errno));
        }

        return false;
    }

    path->assign(resolved);
    ::free(resolved);
    return true;
}

bool pal::file_exists(const pal::string_t& path)
{
    return (::access(path.c_str(), F_OK) == 0);
}

static void readdir(const pal::string_t& path, const pal::string_t& pattern, bool onlydirectories, std::vector<pal::string_t>* list)
{
    assert(list != nullptr);

    std::vector<pal::string_t>& files = *list;

    auto dir = opendir(path.c_str());
    if (dir != nullptr)
    {
        struct dirent* entry = nullptr;
        while ((entry = readdir(dir)) != nullptr)
        {
            if (fnmatch(pattern.c_str(), entry->d_name, FNM_PATHNAME) != 0)
            {
                continue;
            }

            // We are interested in files only
            switch (entry->d_type)
            {
            case DT_DIR:
                break;

            case DT_REG:
                if (onlydirectories)
                {
                    continue;
                }
                break;

            // Handle symlinks and file systems that do not support d_type
            case DT_LNK:
            case DT_UNKNOWN:
                {
                    struct stat sb;

                    if (fstatat(dirfd(dir), entry->d_name, &sb, 0) == -1)
                    {
                        continue;
                    }

                    if (onlydirectories)
                    {
                        if (!S_ISDIR(sb.st_mode))
                        {
                            continue;
                        }
                        break;
                    }
                    else if (!S_ISREG(sb.st_mode) && !S_ISDIR(sb.st_mode))
                    {
                        continue;
                    }
                }
                break;

            default:
                continue;
            }

            if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
            {
                continue;
            }

            files.emplace_back(entry->d_name);
        }

        closedir(dir);
    }
}

void pal::readdir(const string_t& path, const string_t& pattern, std::vector<pal::string_t>* list)
{
    ::readdir(path, pattern, false, list);
}

void pal::readdir(const pal::string_t& path, std::vector<pal::string_t>* list)
{
    ::readdir(path, _X("*"), false, list);
}

void pal::readdir_onlydirectories(const pal::string_t& path, const string_t& pattern, std::vector<pal::string_t>* list)
{
    ::readdir(path, pattern, true, list);
}

void pal::readdir_onlydirectories(const pal::string_t& path, std::vector<pal::string_t>* list)
{
    ::readdir(path, _X("*"), true, list);
}

bool pal::is_running_in_wow64()
{
    return false;
}

bool pal::are_paths_equal_with_normalized_casing(const string_t& path1, const string_t& path2)
{
#if defined(__APPLE__)
    // On Mac, paths are case-insensitive
    return (strcasecmp(path1.c_str(), path2.c_str()) == 0);
#else
    // On Linux, paths are case-sensitive
    return path1 == path2;
#endif
}