Merge branch 'nix' into 'master'.

1 files changed, 1105 insertions, 0 deletions

diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
new file mode 100644
index 0000000000..15c462ce4e
--- /dev/null
+++ b/nix/libutil/util.cc
@@ -0,0 +1,1105 @@
+#include "config.h"
+
+#include <iostream>
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+#include <sstream>
+#include <cstring>
+
+#include <sys/wait.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#ifdef __APPLE__
+#include <sys/syscall.h>
+#endif
+
+#include "util.hh"
+
+
+extern char * * environ;
+
+
+namespace nix {
+
+
+BaseError::BaseError(const FormatOrString & fs, unsigned int status)
+    : status(status)
+{
+    err = fs.s;
+}
+
+
+BaseError & BaseError::addPrefix(const FormatOrString & fs)
+{
+    prefix_ = fs.s + prefix_;
+    return *this;
+}
+
+
+SysError::SysError(const FormatOrString & fs)
+    : Error(format("%1%: %2%") % fs.s % strerror(errno))
+    , errNo(errno)
+{
+}
+
+
+string getEnv(const string & key, const string & def)
+{
+    char * value = getenv(key.c_str());
+    return value ? string(value) : def;
+}
+
+
+Path absPath(Path path, Path dir)
+{
+    if (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");
+            dir = buf;
+#ifdef __GNU__
+            free(buf);
+#endif
+        }
+        path = dir + "/" + path;
+    }
+    return canonPath(path);
+}
+
+
+Path canonPath(const Path & path, bool resolveSymlinks)
+{
+    string s;
+
+    if (path[0] != '/')
+        throw Error(format("not an absolute path: `%1%'") % path);
+
+    string::const_iterator i = path.begin(), end = path.end();
+    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 (i != end && *i == '/') i++;
+        if (i == end) break;
+
+        /* Ignore `.'. */
+        if (*i == '.' && (i + 1 == end || i[1] == '/'))
+            i++;
+
+        /* If `..', delete the last component. */
+        else if (*i == '.' && i + 1 < end && i[1] == '.' &&
+            (i + 2 == end || i[2] == '/'))
+        {
+            if (!s.empty()) s.erase(s.rfind('/'));
+            i += 2;
+        }
+
+        /* Normal component; copy it. */
+        else {
+            s += '/';
+            while (i != end && *i != '/') s += *i++;
+
+            /* If s points to a symlink, resolve it and restart (since
+               the symlink target might contain new symlinks). */
+            if (resolveSymlinks && isLink(s)) {
+                if (++followCount >= maxFollow)
+                    throw Error(format("infinite symlink recursion in path `%1%'") % path);
+                temp = absPath(readLink(s), dirOf(s))
+                    + string(i, end);
+                i = temp.begin(); /* restart */
+                end = temp.end();
+                s = "";
+                /* !!! potential for infinite loop */
+            }
+        }
+    }
+
+    return s.empty() ? "/" : s;
+}
+
+
+Path dirOf(const Path & path)
+{
+    Path::size_type pos = path.rfind('/');
+    if (pos == string::npos)
+        throw Error(format("invalid file name `%1%'") % path);
+    return pos == 0 ? "/" : Path(path, 0, pos);
+}
+
+
+string baseNameOf(const Path & path)
+{
+    Path::size_type pos = path.rfind('/');
+    if (pos == string::npos)
+        throw Error(format("invalid file name `%1%'") % path);
+    return string(path, pos + 1);
+}
+
+
+bool isInDir(const Path & path, const Path & dir)
+{
+    return path[0] == '/'
+        && string(path, 0, dir.size()) == dir
+        && path.size() >= dir.size() + 2
+        && path[dir.size()] == '/';
+}
+
+
+struct stat lstat(const Path & path)
+{
+    struct stat st;
+    if (lstat(path.c_str(), &st))
+        throw SysError(format("getting status of `%1%'") % path);
+    return st;
+}
+
+
+bool pathExists(const Path & path)
+{
+    int res;
+    struct stat st;
+    res = lstat(path.c_str(), &st);
+    if (!res) return true;
+    if (errno != ENOENT && errno != ENOTDIR)
+        throw SysError(format("getting status of %1%") % path);
+    return false;
+}
+
+
+Path readLink(const Path & path)
+{
+    checkInterrupt();
+    struct stat st = lstat(path);
+    if (!S_ISLNK(st.st_mode))
+        throw Error(format("`%1%' is not a symlink") % path);
+    char buf[st.st_size];
+    if (readlink(path.c_str(), buf, st.st_size) != st.st_size)
+        throw SysError(format("reading symbolic link `%1%'") % path);
+    return string(buf, st.st_size);
+}
+
+
+bool isLink(const Path & path)
+{
+    struct stat st = lstat(path);
+    return S_ISLNK(st.st_mode);
+}
+
+
+Strings readDirectory(const Path & path)
+{
+    Strings names;
+
+    AutoCloseDir dir = opendir(path.c_str());
+    if (!dir) throw SysError(format("opening directory `%1%'") % path);
+
+    struct dirent * dirent;
+    while (errno = 0, dirent = readdir(dir)) { /* sic */
+        checkInterrupt();
+        string name = dirent->d_name;
+        if (name == "." || name == "..") continue;
+        names.push_back(name);
+    }
+    if (errno) throw SysError(format("reading directory `%1%'") % path);
+
+    return names;
+}
+
+
+string readFile(int fd)
+{
+    struct stat st;
+    if (fstat(fd, &st) == -1)
+        throw SysError("statting file");
+
+    unsigned char * buf = new unsigned char[st.st_size];
+    AutoDeleteArray<unsigned char> d(buf);
+    readFull(fd, buf, st.st_size);
+
+    return string((char *) buf, st.st_size);
+}
+
+
+string readFile(const Path & path, bool drain)
+{
+    AutoCloseFD fd = open(path.c_str(), O_RDONLY);
+    if (fd == -1)
+        throw SysError(format("opening file `%1%'") % path);
+    return drain ? drainFD(fd) : readFile(fd);
+}
+
+
+void writeFile(const Path & path, const string & s)
+{
+    AutoCloseFD fd = open(path.c_str(), O_WRONLY | O_TRUNC | O_CREAT, 0666);
+    if (fd == -1)
+        throw SysError(format("opening file `%1%'") % path);
+    writeFull(fd, (unsigned char *) s.data(), s.size());
+}
+
+
+string readLine(int fd)
+{
+    string s;
+    while (1) {
+        checkInterrupt();
+        char ch;
+        ssize_t rd = read(fd, &ch, 1);
+        if (rd == -1) {
+            if (errno != EINTR)
+                throw SysError("reading a line");
+        } else if (rd == 0)
+            throw EndOfFile("unexpected EOF reading a line");
+        else {
+            if (ch == '\n') return s;
+            s += ch;
+        }
+    }
+}
+
+
+void writeLine(int fd, string s)
+{
+    s += '\n';
+    writeFull(fd, (const unsigned char *) s.data(), s.size());
+}
+
+
+static void _deletePath(const Path & path, unsigned long long & bytesFreed)
+{
+    checkInterrupt();
+
+    printMsg(lvlVomit, format("%1%") % path);
+
+    struct stat st = lstat(path);
+
+    if (!S_ISDIR(st.st_mode) && st.st_nlink == 1)
+        bytesFreed += st.st_blocks * 512;
+
+    if (S_ISDIR(st.st_mode)) {
+        Strings names = readDirectory(path);
+
+        /* Make the directory writable. */
+        if (!(st.st_mode & S_IWUSR)) {
+            if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1)
+                throw SysError(format("making `%1%' writable") % path);
+        }
+
+        for (Strings::iterator i = names.begin(); i != names.end(); ++i)
+            _deletePath(path + "/" + *i, bytesFreed);
+    }
+
+    if (remove(path.c_str()) == -1)
+        throw SysError(format("cannot unlink `%1%'") % path);
+}
+
+
+void deletePath(const Path & path)
+{
+    unsigned long long dummy;
+    deletePath(path, dummy);
+}
+
+
+void deletePath(const Path & path, unsigned long long & bytesFreed)
+{
+    startNest(nest, lvlDebug,
+        format("recursively deleting path `%1%'") % path);
+    bytesFreed = 0;
+    _deletePath(path, bytesFreed);
+}
+
+
+static Path tempName(Path tmpRoot, const Path & prefix, bool includePid,
+    int & counter)
+{
+    tmpRoot = canonPath(tmpRoot.empty() ? getEnv("TMPDIR", "/tmp") : tmpRoot, true);
+    if (includePid)
+        return (format("%1%/%2%-%3%-%4%") % tmpRoot % prefix % getpid() % counter++).str();
+    else
+        return (format("%1%/%2%-%3%") % tmpRoot % prefix % counter++).str();
+}
+
+
+Path createTempDir(const Path & tmpRoot, const Path & prefix,
+    bool includePid, bool useGlobalCounter, mode_t mode)
+{
+    static int globalCounter = 0;
+    int localCounter = 0;
+    int & counter(useGlobalCounter ? globalCounter : localCounter);
+
+    while (1) {
+        checkInterrupt();
+        Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
+        if (mkdir(tmpDir.c_str(), mode) == 0) {
+            /* Explicitly set the group of the directory.  This is to
+               work around around problems caused by BSD's group
+               ownership semantics (directories inherit the group of
+               the parent).  For instance, the group of /tmp on
+               FreeBSD is "wheel", so all directories created in /tmp
+               will be owned by "wheel"; but if the user is not in
+               "wheel", then "tar" will fail to unpack archives that
+               have the setgid bit set on directories. */
+            if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
+                throw SysError(format("setting group of directory `%1%'") % tmpDir);
+            return tmpDir;
+        }
+        if (errno != EEXIST)
+            throw SysError(format("creating directory `%1%'") % tmpDir);
+    }
+}
+
+
+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(format("creating directory `%1%'") % path);
+        st = lstat(path);
+        created.push_back(path);
+    }
+
+    if (!S_ISDIR(st.st_mode)) throw Error(format("`%1%' is not a directory") % path);
+
+    return created;
+}
+
+
+void createSymlink(const Path & target, const Path & link)
+{
+    if (symlink(target.c_str(), link.c_str()))
+        throw SysError(format("creating symlink from `%1%' to `%2%'") % link % target);
+}
+
+
+LogType logType = ltPretty;
+Verbosity verbosity = lvlInfo;
+
+static int nestingLevel = 0;
+
+
+Nest::Nest()
+{
+    nest = false;
+}
+
+
+Nest::~Nest()
+{
+    close();
+}
+
+
+static string escVerbosity(Verbosity level)
+{
+    return int2String((int) level);
+}
+
+
+void Nest::open(Verbosity level, const FormatOrString & fs)
+{
+    if (level <= verbosity) {
+        if (logType == ltEscapes)
+            std::cerr << "\033[" << escVerbosity(level) << "p"
+                      << fs.s << "\n";
+        else
+            printMsg_(level, fs);
+        nest = true;
+        nestingLevel++;
+    }
+}
+
+
+void Nest::close()
+{
+    if (nest) {
+        nestingLevel--;
+        if (logType == ltEscapes)
+            std::cerr << "\033[q";
+        nest = false;
+    }
+}
+
+
+void printMsg_(Verbosity level, const FormatOrString & fs)
+{
+    checkInterrupt();
+    if (level > verbosity) return;
+    string prefix;
+    if (logType == ltPretty)
+        for (int i = 0; i < nestingLevel; i++)
+            prefix += "|   ";
+    else if (logType == ltEscapes && level != lvlInfo)
+        prefix = "\033[" + escVerbosity(level) + "s";
+    string s = (format("%1%%2%\n") % prefix % fs.s).str();
+    writeToStderr(s);
+}
+
+
+void warnOnce(bool & haveWarned, const FormatOrString & fs)
+{
+    if (!haveWarned) {
+        printMsg(lvlError, format("warning: %1%") % fs.s);
+        haveWarned = true;
+    }
+}
+
+
+void writeToStderr(const string & s)
+{
+    try {
+        _writeToStderr((const unsigned char *) s.data(), s.size());
+    } catch (SysError & e) {
+        /* Ignore failing writes to stderr if we're in an exception
+           handler, otherwise throw an exception.  We need to ignore
+           write errors in exception handlers to ensure that cleanup
+           code runs to completion if the other side of stderr has
+           been closed unexpectedly. */
+        if (!std::uncaught_exception()) throw;
+    }
+}
+
+
+static void defaultWriteToStderr(const unsigned char * buf, size_t count)
+{
+    writeFull(STDERR_FILENO, buf, count);
+}
+
+
+void (*_writeToStderr) (const unsigned char * buf, size_t count) = defaultWriteToStderr;
+
+
+void readFull(int fd, unsigned char * buf, size_t count)
+{
+    while (count) {
+        checkInterrupt();
+        ssize_t res = read(fd, (char *) buf, count);
+        if (res == -1) {
+            if (errno == EINTR) continue;
+            throw SysError("reading from file");
+        }
+        if (res == 0) throw EndOfFile("unexpected end-of-file");
+        count -= res;
+        buf += res;
+    }
+}
+
+
+void writeFull(int fd, const unsigned char * buf, size_t count)
+{
+    while (count) {
+        checkInterrupt();
+        ssize_t res = write(fd, (char *) buf, count);
+        if (res == -1) {
+            if (errno == EINTR) continue;
+            throw SysError("writing to file");
+        }
+        count -= res;
+        buf += res;
+    }
+}
+
+
+string drainFD(int fd)
+{
+    string result;
+    unsigned char buffer[4096];
+    while (1) {
+        checkInterrupt();
+        ssize_t rd = read(fd, buffer, sizeof buffer);
+        if (rd == -1) {
+            if (errno != EINTR)
+                throw SysError("reading from file");
+        }
+        else if (rd == 0) break;
+        else result.append((char *) buffer, rd);
+    }
+    return result;
+}
+
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+AutoDelete::AutoDelete(const 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(format("cannot unlink `%1%'") % path);
+            }
+        }
+    } catch (...) {
+        ignoreException();
+    }
+}
+
+void AutoDelete::cancel()
+{
+    del = false;
+}
+
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+AutoCloseFD::AutoCloseFD()
+{
+    fd = -1;
+}
+
+
+AutoCloseFD::AutoCloseFD(int fd)
+{
+    this->fd = fd;
+}
+
+
+AutoCloseFD::AutoCloseFD(const AutoCloseFD & fd)
+{
+    /* Copying an AutoCloseFD isn't allowed (who should get to close
+       it?).  But as an edge case, allow copying of closed
+       AutoCloseFDs.  This is necessary due to tiresome reasons
+       involving copy constructor use on default object values in STL
+       containers (like when you do `map[value]' where value isn't in
+       the map yet). */
+    this->fd = fd.fd;
+    if (this->fd != -1) abort();
+}
+
+
+AutoCloseFD::~AutoCloseFD()
+{
+    try {
+        close();
+    } catch (...) {
+        ignoreException();
+    }
+}
+
+
+void AutoCloseFD::operator =(int fd)
+{
+    if (this->fd != fd) close();
+    this->fd = fd;
+}
+
+
+AutoCloseFD::operator int() const
+{
+    return fd;
+}
+
+
+void AutoCloseFD::close()
+{
+    if (fd != -1) {
+        if (::close(fd) == -1)
+            /* This should never happen. */
+            throw SysError(format("closing file descriptor %1%") % fd);
+        fd = -1;
+    }
+}
+
+
+bool AutoCloseFD::isOpen()
+{
+    return fd != -1;
+}
+
+
+/* Pass responsibility for closing this fd to the caller. */
+int AutoCloseFD::borrow()
+{
+    int oldFD = fd;
+    fd = -1;
+    return oldFD;
+}
+
+
+void Pipe::create()
+{
+    int fds[2];
+    if (pipe(fds) != 0) throw SysError("creating pipe");
+    readSide = fds[0];
+    writeSide = fds[1];
+    closeOnExec(readSide);
+    closeOnExec(writeSide);
+}
+
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+AutoCloseDir::AutoCloseDir()
+{
+    dir = 0;
+}
+
+
+AutoCloseDir::AutoCloseDir(DIR * dir)
+{
+    this->dir = dir;
+}
+
+
+AutoCloseDir::~AutoCloseDir()
+{
+    close();
+}
+
+
+void AutoCloseDir::operator =(DIR * dir)
+{
+    this->dir = dir;
+}
+
+
+AutoCloseDir::operator DIR *()
+{
+    return dir;
+}
+
+
+void AutoCloseDir::close()
+{
+    if (dir) {
+        closedir(dir);
+        dir = 0;
+    }
+}
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+Pid::Pid()
+{
+    pid = -1;
+    separatePG = false;
+    killSignal = SIGKILL;
+}
+
+
+Pid::~Pid()
+{
+    kill();
+}
+
+
+void Pid::operator =(pid_t pid)
+{
+    if (this->pid != pid) kill();
+    this->pid = pid;
+    killSignal = SIGKILL; // reset signal to default
+}
+
+
+Pid::operator pid_t()
+{
+    return pid;
+}
+
+
+void Pid::kill()
+{
+    if (pid == -1 || pid == 0) return;
+
+    printMsg(lvlError, format("killing process %1%") % pid);
+
+    /* Send the requested signal to the child.  If it has its own
+       process group, send the signal to every process in the child
+       process group (which hopefully includes *all* its children). */
+    if (::kill(separatePG ? -pid : pid, killSignal) != 0)
+        printMsg(lvlError, (SysError(format("killing process %1%") % pid).msg()));
+
+    /* Wait until the child dies, disregarding the exit status. */
+    int status;
+    while (waitpid(pid, &status, 0) == -1) {
+        checkInterrupt();
+        if (errno != EINTR) {
+            printMsg(lvlError,
+                (SysError(format("waiting for process %1%") % pid).msg()));
+            break;
+        }
+    }
+
+    pid = -1;
+}
+
+
+int Pid::wait(bool block)
+{
+    assert(pid != -1);
+    while (1) {
+        int status;
+        int res = waitpid(pid, &status, block ? 0 : WNOHANG);
+        if (res == pid) {
+            pid = -1;
+            return status;
+        }
+        if (res == 0 && !block) return -1;
+        if (errno != EINTR)
+            throw SysError("cannot get child exit status");
+        checkInterrupt();
+    }
+}
+
+
+void Pid::setSeparatePG(bool separatePG)
+{
+    this->separatePG = separatePG;
+}
+
+
+void Pid::setKillSignal(int signal)
+{
+    this->killSignal = signal;
+}
+
+
+void killUser(uid_t uid)
+{
+    debug(format("killing all processes running under uid `%1%'") % uid);
+
+    assert(uid != 0); /* just to be safe... */
+
+    /* The system call kill(-1, sig) sends the signal `sig' to all
+       users to which the current process can send signals.  So we
+       fork a process, switch to uid, and send a mass kill. */
+
+    Pid pid;
+    pid = fork();
+    switch (pid) {
+
+    case -1:
+        throw SysError("unable to fork");
+
+    case 0:
+        try { /* child */
+
+            if (setuid(uid) == -1)
+                throw SysError("setting uid");
+
+            while (true) {
+#ifdef __APPLE__
+                /* OSX's kill syscall takes a third parameter that, among other
+                   things, determines if kill(-1, signo) affects the calling
+                   process. In the OSX libc, it's set to true, which means
+                   "follow POSIX", which we don't want here
+                 */
+                if (syscall(SYS_kill, -1, SIGKILL, false) == 0) break;
+#else
+                if (kill(-1, SIGKILL) == 0) break;
+#endif
+                if (errno == ESRCH) break; /* no more processes */
+                if (errno != EINTR)
+                    throw SysError(format("cannot kill processes for uid `%1%'") % uid);
+            }
+
+        } catch (std::exception & e) {
+            writeToStderr((format("killing processes belonging to uid `%1%': %2%\n") % uid % e.what()).str());
+            _exit(1);
+        }
+        _exit(0);
+    }
+
+    /* parent */
+    int status = pid.wait(true);
+    if (status != 0)
+        throw Error(format("cannot kill processes for uid `%1%': %2%") % uid % statusToString(status));
+
+    /* !!! We should really do some check to make sure that there are
+       no processes left running under `uid', but there is no portable
+       way to do so (I think).  The most reliable way may be `ps -eo
+       uid | grep -q $uid'. */
+}
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+string runProgram(Path program, bool searchPath, const Strings & args)
+{
+    checkInterrupt();
+
+    std::vector<const char *> cargs; /* careful with c_str()! */
+    cargs.push_back(program.c_str());
+    for (Strings::const_iterator i = args.begin(); i != args.end(); ++i)
+        cargs.push_back(i->c_str());
+    cargs.push_back(0);
+
+    /* Create a pipe. */
+    Pipe pipe;
+    pipe.create();
+
+    /* Fork. */
+    Pid pid;
+    pid = maybeVfork();
+
+    switch (pid) {
+
+    case -1:
+        throw SysError("unable to fork");
+
+    case 0: /* child */
+        try {
+            if (dup2(pipe.writeSide, STDOUT_FILENO) == -1)
+                throw SysError("dupping stdout");
+
+            if (searchPath)
+                execvp(program.c_str(), (char * *) &cargs[0]);
+            else
+                execv(program.c_str(), (char * *) &cargs[0]);
+            throw SysError(format("executing `%1%'") % program);
+
+        } catch (std::exception & e) {
+            writeToStderr("error: " + string(e.what()) + "\n");
+        }
+        _exit(1);
+    }
+
+    /* Parent. */
+
+    pipe.writeSide.close();
+
+    string result = drainFD(pipe.readSide);
+
+    /* Wait for the child to finish. */
+    int status = pid.wait(true);
+    if (!statusOk(status))
+        throw Error(format("program `%1%' %2%")
+            % program % statusToString(status));
+
+    return result;
+}
+
+
+void closeMostFDs(const set<int> & exceptions)
+{
+    int maxFD = 0;
+    maxFD = sysconf(_SC_OPEN_MAX);
+    for (int fd = 0; fd < maxFD; ++fd)
+        if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO
+            && exceptions.find(fd) == exceptions.end())
+            close(fd); /* ignore result */
+}
+
+
+void closeOnExec(int fd)
+{
+    int prev;
+    if ((prev = fcntl(fd, F_GETFD, 0)) == -1 ||
+        fcntl(fd, F_SETFD, prev | FD_CLOEXEC) == -1)
+        throw SysError("setting close-on-exec flag");
+}
+
+
+#if HAVE_VFORK
+pid_t (*maybeVfork)() = vfork;
+#else
+pid_t (*maybeVfork)() = fork;
+#endif
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+volatile sig_atomic_t _isInterrupted = 0;
+
+void _interrupted()
+{
+    /* Block user interrupts while an exception is being handled.
+       Throwing an exception while another exception is being handled
+       kills the program! */
+    if (!std::uncaught_exception()) {
+        _isInterrupted = 0;
+        throw Interrupted("interrupted by the user");
+    }
+}
+
+
+
+//////////////////////////////////////////////////////////////////////
+
+
+template<class C> C tokenizeString(const string & s, const string & separators)
+{
+    C result;
+    string::size_type pos = s.find_first_not_of(separators, 0);
+    while (pos != string::npos) {
+        string::size_type end = s.find_first_of(separators, pos + 1);
+        if (end == string::npos) end = s.size();
+        string token(s, pos, end - pos);
+        result.insert(result.end(), token);
+        pos = s.find_first_not_of(separators, end);
+    }
+    return result;
+}
+
+template Strings tokenizeString(const string & s, const string & separators);
+template StringSet tokenizeString(const string & s, const string & separators);
+template vector<string> tokenizeString(const string & s, const string & separators);
+
+
+string concatStringsSep(const string & sep, const Strings & ss)
+{
+    string s;
+    foreach (Strings::const_iterator, i, ss) {
+        if (s.size() != 0) s += sep;
+        s += *i;
+    }
+    return s;
+}
+
+
+string concatStringsSep(const string & sep, const StringSet & ss)
+{
+    string s;
+    foreach (StringSet::const_iterator, i, ss) {
+        if (s.size() != 0) s += sep;
+        s += *i;
+    }
+    return s;
+}
+
+
+string chomp(const string & s)
+{
+    size_t i = s.find_last_not_of(" \n\r\t");
+    return i == string::npos ? "" : string(s, 0, i + 1);
+}
+
+
+string statusToString(int status)
+{
+    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+        if (WIFEXITED(status))
+            return (format("failed with exit code %1%") % WEXITSTATUS(status)).str();
+        else if (WIFSIGNALED(status)) {
+            int sig = WTERMSIG(status);
+#if HAVE_STRSIGNAL
+            const char * description = strsignal(sig);
+            return (format("failed due to signal %1% (%2%)") % sig % description).str();
+#else
+            return (format("failed due to signal %1%") % sig).str();
+#endif
+        }
+        else
+            return "died abnormally";
+    } else return "succeeded";
+}
+
+
+bool statusOk(int status)
+{
+    return WIFEXITED(status) && WEXITSTATUS(status) == 0;
+}
+
+
+bool hasSuffix(const string & s, const string & suffix)
+{
+    return s.size() >= suffix.size() && string(s, s.size() - suffix.size()) == suffix;
+}
+
+
+void expect(std::istream & str, const string & s)
+{
+    char s2[s.size()];
+    str.read(s2, s.size());
+    if (string(s2, s.size()) != s)
+        throw Error(format("expected string `%1%'") % s);
+}
+
+
+string parseString(std::istream & str)
+{
+    string res;
+    expect(str, "\"");
+    int c;
+    while ((c = str.get()) != '"')
+        if (c == '\\') {
+            c = str.get();
+            if (c == 'n') res += '\n';
+            else if (c == 'r') res += '\r';
+            else if (c == 't') res += '\t';
+            else res += c;
+        }
+        else res += c;
+    return res;
+}
+
+
+bool endOfList(std::istream & str)
+{
+    if (str.peek() == ',') {
+        str.get();
+        return false;
+    }
+    if (str.peek() == ']') {
+        str.get();
+        return true;
+    }
+    return false;
+}
+
+
+string decodeOctalEscaped(const string & s)
+{
+    string r;
+    for (string::const_iterator i = s.begin(); i != s.end(); ) {
+        if (*i != '\\') { r += *i++; continue; }
+        unsigned char c = 0;
+        ++i;
+        while (i != s.end() && *i >= '0' && *i < '8')
+            c = c * 8 + (*i++ - '0');
+        r += c;
+    }
+    return r;
+}
+
+
+void ignoreException()
+{
+    try {
+        throw;
+    } catch (std::exception & e) {
+        printMsg(lvlError, format("error (ignored): %1%") % e.what());
+    }
+}
+
+
+}