util.{hh,cc}: Split out file-system.{hh,cc}

Change-Id: Ifa89a529e7e34e7291eca87d802d2f569cf2493e

1 files changed, 1 insertions, 500 deletions

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 63d9e5248..ac3071ba8 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -5,6 +5,7 @@
 #include "cgroup.hh"
 #include "signals.hh"
 #include "environment-variables.hh"
+#include "file-system.hh"
 
 #include <array>
 #include <cctype>
@@ -50,352 +51,6 @@
 
 namespace nix {
 
-Path absPath(Path path, std::optional<PathView> dir, bool resolveSymlinks)
-{
-    if (path.empty() || path[0] != '/') {
-        if (!dir) {
-#ifdef __GNU__
-            /* GNU (aka. GNU/Hurd) doesn't have any limitation on path
-               lengths and doesn't define `PATH_MAX'.  */
-            char *buf = getcwd(NULL, 0);
-            if (buf == NULL)
-#else
-            char buf[PATH_MAX];
-            if (!getcwd(buf, sizeof(buf)))
-#endif
-                throw SysError("cannot get cwd");
-            path = concatStrings(buf, "/", path);
-#ifdef __GNU__
-            free(buf);
-#endif
-        } else
-            path = concatStrings(*dir, "/", path);
-    }
-    return canonPath(path, resolveSymlinks);
-}
-
-
-Path canonPath(PathView path, bool resolveSymlinks)
-{
-    assert(path != "");
-
-    std::string s;
-    s.reserve(256);
-
-    if (path[0] != '/')
-        throw Error("not an absolute path: '%1%'", path);
-
-    std::string temp;
-
-    /* Count the number of times we follow a symlink and stop at some
-       arbitrary (but high) limit to prevent infinite loops. */
-    unsigned int followCount = 0, maxFollow = 1024;
-
-    while (1) {
-
-        /* Skip slashes. */
-        while (!path.empty() && path[0] == '/') path.remove_prefix(1);
-        if (path.empty()) break;
-
-        /* Ignore `.'. */
-        if (path == "." || path.substr(0, 2) == "./")
-            path.remove_prefix(1);
-
-        /* If `..', delete the last component. */
-        else if (path == ".." || path.substr(0, 3) == "../")
-        {
-            if (!s.empty()) s.erase(s.rfind('/'));
-            path.remove_prefix(2);
-        }
-
-        /* Normal component; copy it. */
-        else {
-            s += '/';
-            if (const auto slash = path.find('/'); slash == std::string::npos) {
-                s += path;
-                path = {};
-            } else {
-                s += path.substr(0, slash);
-                path = path.substr(slash);
-            }
-
-            /* If s points to a symlink, resolve it and continue from there */
-            if (resolveSymlinks && isLink(s)) {
-                if (++followCount >= maxFollow)
-                    throw Error("infinite symlink recursion in path '%1%'", path);
-                temp = concatStrings(readLink(s), path);
-                path = temp;
-                if (!temp.empty() && temp[0] == '/') {
-                    s.clear();  /* restart for symlinks pointing to absolute path */
-                } else {
-                    s = dirOf(s);
-                    if (s == "/") {  // we don’t want trailing slashes here, which dirOf only produces if s = /
-                        s.clear();
-                    }
-                }
-            }
-        }
-    }
-
-    return s.empty() ? "/" : std::move(s);
-}
-
-void chmodPath(const Path & path, mode_t mode)
-{
-    if (chmod(path.c_str(), mode) == -1)
-        throw SysError("setting permissions on '%s'", path);
-}
-
-Path dirOf(const PathView path)
-{
-    Path::size_type pos = path.rfind('/');
-    if (pos == std::string::npos)
-        return ".";
-    return pos == 0 ? "/" : Path(path, 0, pos);
-}
-
-
-std::string_view baseNameOf(std::string_view path)
-{
-    if (path.empty())
-        return "";
-
-    auto last = path.size() - 1;
-    if (path[last] == '/' && last > 0)
-        last -= 1;
-
-    auto pos = path.rfind('/', last);
-    if (pos == std::string::npos)
-        pos = 0;
-    else
-        pos += 1;
-
-    return path.substr(pos, last - pos + 1);
-}
-
-
-std::string expandTilde(std::string_view path)
-{
-    // TODO: expand ~user ?
-    auto tilde = path.substr(0, 2);
-    if (tilde == "~/" || tilde == "~")
-        return getHome() + std::string(path.substr(1));
-    else
-        return std::string(path);
-}
-
-
-bool isInDir(std::string_view path, std::string_view dir)
-{
-    return path.substr(0, 1) == "/"
-        && path.substr(0, dir.size()) == dir
-        && path.size() >= dir.size() + 2
-        && path[dir.size()] == '/';
-}
-
-
-bool isDirOrInDir(std::string_view path, std::string_view dir)
-{
-    return path == dir || isInDir(path, dir);
-}
-
-
-struct stat stat(const Path & path)
-{
-    struct stat st;
-    if (stat(path.c_str(), &st))
-        throw SysError("getting status of '%1%'", path);
-    return st;
-}
-
-
-struct stat lstat(const Path & path)
-{
-    struct stat st;
-    if (lstat(path.c_str(), &st))
-        throw SysError("getting status of '%1%'", path);
-    return st;
-}
-
-std::optional<struct stat> maybeLstat(const Path & path)
-{
-    std::optional<struct stat> st{std::in_place};
-    if (lstat(path.c_str(), &*st))
-    {
-        if (errno == ENOENT || errno == ENOTDIR)
-            st.reset();
-        else
-            throw SysError("getting status of '%s'", path);
-    }
-    return st;
-}
-
-bool pathExists(const Path & path)
-{
-    return maybeLstat(path).has_value();
-}
-
-bool pathAccessible(const Path & path)
-{
-    try {
-        return pathExists(path);
-    } catch (SysError & e) {
-        // swallow EPERM
-        if (e.errNo == EPERM) return false;
-        throw;
-    }
-}
-
-
-Path readLink(const Path & path)
-{
-    checkInterrupt();
-    std::vector<char> buf;
-    for (ssize_t bufSize = PATH_MAX/4; true; bufSize += bufSize/2) {
-        buf.resize(bufSize);
-        ssize_t rlSize = readlink(path.c_str(), buf.data(), bufSize);
-        if (rlSize == -1)
-            if (errno == EINVAL)
-                throw Error("'%1%' is not a symlink", path);
-            else
-                throw SysError("reading symbolic link '%1%'", path);
-        else if (rlSize < bufSize)
-            return std::string(buf.data(), rlSize);
-    }
-}
-
-
-bool isLink(const Path & path)
-{
-    struct stat st = lstat(path);
-    return S_ISLNK(st.st_mode);
-}
-
-
-DirEntries readDirectory(DIR *dir, const Path & path)
-{
-    DirEntries entries;
-    entries.reserve(64);
-
-    struct dirent * dirent;
-    while (errno = 0, dirent = readdir(dir)) { /* sic */
-        checkInterrupt();
-        std::string name = dirent->d_name;
-        if (name == "." || name == "..") continue;
-        entries.emplace_back(name, dirent->d_ino,
-#ifdef HAVE_STRUCT_DIRENT_D_TYPE
-            dirent->d_type
-#else
-            DT_UNKNOWN
-#endif
-        );
-    }
-    if (errno) throw SysError("reading directory '%1%'", path);
-
-    return entries;
-}
-
-DirEntries readDirectory(const Path & path)
-{
-    AutoCloseDir dir(opendir(path.c_str()));
-    if (!dir) throw SysError("opening directory '%1%'", path);
-
-    return readDirectory(dir.get(), path);
-}
-
-
-unsigned char getFileType(const Path & path)
-{
-    struct stat st = lstat(path);
-    if (S_ISDIR(st.st_mode)) return DT_DIR;
-    if (S_ISLNK(st.st_mode)) return DT_LNK;
-    if (S_ISREG(st.st_mode)) return DT_REG;
-    return DT_UNKNOWN;
-}
-
-
-std::string readFile(int fd)
-{
-    struct stat st;
-    if (fstat(fd, &st) == -1)
-        throw SysError("statting file");
-
-    return drainFD(fd, true, st.st_size);
-}
-
-
-std::string readFile(const Path & path)
-{
-    AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    return readFile(fd.get());
-}
-
-
-void readFile(const Path & path, Sink & sink)
-{
-    AutoCloseFD fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)};
-    if (!fd)
-        throw SysError("opening file '%s'", path);
-    drainFD(fd.get(), sink);
-}
-
-
-void writeFile(const Path & path, std::string_view s, mode_t mode, bool sync)
-{
-    AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    try {
-        writeFull(fd.get(), s);
-    } catch (Error & e) {
-        e.addTrace({}, "writing file '%1%'", path);
-        throw;
-    }
-    if (sync)
-        fd.fsync();
-    // Explicitly close to make sure exceptions are propagated.
-    fd.close();
-    if (sync)
-        syncParent(path);
-}
-
-
-void writeFile(const Path & path, Source & source, mode_t mode, bool sync)
-{
-    AutoCloseFD fd{open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-
-    std::vector<char> buf(64 * 1024);
-
-    try {
-        while (true) {
-            try {
-                auto n = source.read(buf.data(), buf.size());
-                writeFull(fd.get(), {buf.data(), n});
-            } catch (EndOfFile &) { break; }
-        }
-    } catch (Error & e) {
-        e.addTrace({}, "writing file '%1%'", path);
-        throw;
-    }
-    if (sync)
-        fd.fsync();
-    // Explicitly close to make sure exceptions are propagated.
-    fd.close();
-    if (sync)
-        syncParent(path);
-}
-
-void syncParent(const Path & path)
-{
-    AutoCloseFD fd{open(dirOf(path).c_str(), O_RDONLY, 0)};
-    if (!fd)
-        throw SysError("opening file '%1%'", path);
-    fd.fsync();
-}
 
 std::string readLine(int fd)
 {
@@ -425,98 +80,6 @@ void writeLine(int fd, std::string s)
 }
 
 
-static void _deletePath(int parentfd, const Path & path, uint64_t & bytesFreed)
-{
-    checkInterrupt();
-
-    std::string name(baseNameOf(path));
-
-    struct stat st;
-    if (fstatat(parentfd, name.c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
-        if (errno == ENOENT) return;
-        throw SysError("getting status of '%1%'", path);
-    }
-
-    if (!S_ISDIR(st.st_mode)) {
-        /* We are about to delete a file. Will it likely free space? */
-
-        switch (st.st_nlink) {
-            /* Yes: last link. */
-            case 1:
-                bytesFreed += st.st_size;
-                break;
-            /* Maybe: yes, if 'auto-optimise-store' or manual optimisation
-               was performed. Instead of checking for real let's assume
-               it's an optimised file and space will be freed.
-
-               In worst case we will double count on freed space for files
-               with exactly two hardlinks for unoptimised packages.
-             */
-            case 2:
-                bytesFreed += st.st_size;
-                break;
-            /* No: 3+ links. */
-            default:
-                break;
-        }
-    }
-
-    if (S_ISDIR(st.st_mode)) {
-        /* Make the directory accessible. */
-        const auto PERM_MASK = S_IRUSR | S_IWUSR | S_IXUSR;
-        if ((st.st_mode & PERM_MASK) != PERM_MASK) {
-            if (fchmodat(parentfd, name.c_str(), st.st_mode | PERM_MASK, 0) == -1)
-                throw SysError("chmod '%1%'", path);
-        }
-
-        int fd = openat(parentfd, path.c_str(), O_RDONLY);
-        if (fd == -1)
-            throw SysError("opening directory '%1%'", path);
-        AutoCloseDir dir(fdopendir(fd));
-        if (!dir)
-            throw SysError("opening directory '%1%'", path);
-        for (auto & i : readDirectory(dir.get(), path))
-            _deletePath(dirfd(dir.get()), path + "/" + i.name, bytesFreed);
-    }
-
-    int flags = S_ISDIR(st.st_mode) ? AT_REMOVEDIR : 0;
-    if (unlinkat(parentfd, name.c_str(), flags) == -1) {
-        if (errno == ENOENT) return;
-        throw SysError("cannot unlink '%1%'", path);
-    }
-}
-
-static void _deletePath(const Path & path, uint64_t & bytesFreed)
-{
-    Path dir = dirOf(path);
-    if (dir == "")
-        dir = "/";
-
-    AutoCloseFD dirfd{open(dir.c_str(), O_RDONLY)};
-    if (!dirfd) {
-        if (errno == ENOENT) return;
-        throw SysError("opening directory '%1%'", path);
-    }
-
-    _deletePath(dirfd.get(), path, bytesFreed);
-}
-
-
-void deletePath(const Path & path)
-{
-    uint64_t dummy;
-    deletePath(path, dummy);
-}
-
-
-void deletePath(const Path & path, uint64_t & bytesFreed)
-{
-    //Activity act(*logger, lvlDebug, "recursively deleting path '%1%'", path);
-    bytesFreed = 0;
-    _deletePath(path, bytesFreed);
-}
-
-
 std::string getUserName()
 {
     auto pw = getpwuid(geteuid());
@@ -632,28 +195,6 @@ std::optional<Path> getSelfExe()
 }
 
 
-Paths createDirs(const Path & path)
-{
-    Paths created;
-    if (path == "/") return created;
-
-    struct stat st;
-    if (lstat(path.c_str(), &st) == -1) {
-        created = createDirs(dirOf(path));
-        if (mkdir(path.c_str(), 0777) == -1 && errno != EEXIST)
-            throw SysError("creating directory '%1%'", path);
-        st = lstat(path);
-        created.push_back(path);
-    }
-
-    if (S_ISLNK(st.st_mode) && stat(path.c_str(), &st) == -1)
-        throw SysError("statting symlink '%1%'", path);
-
-    if (!S_ISDIR(st.st_mode)) throw Error("'%1%' is not a directory", path);
-
-    return created;
-}
-
 
 void readFull(int fd, char * buf, size_t count)
 {
@@ -762,46 +303,6 @@ unsigned int getMaxCPU()
 //////////////////////////////////////////////////////////////////////
 
 
-AutoDelete::AutoDelete() : del{false} {}
-
-AutoDelete::AutoDelete(const std::string & p, bool recursive) : path(p)
-{
-    del = true;
-    this->recursive = recursive;
-}
-
-AutoDelete::~AutoDelete()
-{
-    try {
-        if (del) {
-            if (recursive)
-                deletePath(path);
-            else {
-                if (remove(path.c_str()) == -1)
-                    throw SysError("cannot unlink '%1%'", path);
-            }
-        }
-    } catch (...) {
-        ignoreException();
-    }
-}
-
-void AutoDelete::cancel()
-{
-    del = false;
-}
-
-void AutoDelete::reset(const Path & p, bool recursive) {
-    path = p;
-    this->recursive = recursive;
-    del = true;
-}
-
-
-
-//////////////////////////////////////////////////////////////////////
-
-
 AutoCloseFD::AutoCloseFD() : fd{-1} {}