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lix/src/libutil/util.cc
Eelco Dolstra 3007f57377 Remove tabs
2013-01-03 13:00:46 +01:00

1144 lines
25 KiB
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#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>
#include "util.hh"
extern char * * environ;
namespace nix {
BaseError::BaseError(const format & f, unsigned int status)
: status(status)
{
err = f.str();
}
BaseError & BaseError::addPrefix(const format & f)
{
prefix_ = f.str() + prefix_;
return *this;
}
SysError::SysError(const format & f)
: Error(format("%1%: %2%") % f.str() % 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);
}
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 _computePathSize(const Path & path,
unsigned long long & bytes, unsigned long long & blocks)
{
checkInterrupt();
struct stat st = lstat(path);
bytes += st.st_size;
blocks += st.st_blocks;
if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
for (Strings::iterator i = names.begin(); i != names.end(); ++i)
_computePathSize(path + "/" + *i, bytes, blocks);
}
}
void computePathSize(const Path & path,
unsigned long long & bytes, unsigned long long & blocks)
{
bytes = 0;
blocks = 0;
_computePathSize(path, bytes, blocks);
}
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);
}
void makePathReadOnly(const Path & path)
{
checkInterrupt();
struct stat st = lstat(path);
if (!S_ISLNK(st.st_mode) && (st.st_mode & S_IWUSR)) {
if (chmod(path.c_str(), st.st_mode & ~S_IWUSR) == -1)
throw SysError(format("making `%1%' read-only") % path);
}
if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
for (Strings::iterator i = names.begin(); i != names.end(); ++i)
makePathReadOnly(path + "/" + *i);
}
}
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;
}
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 format & f)
{
if (level <= verbosity) {
if (logType == ltEscapes)
std::cerr << "\033[" << escVerbosity(level) << "p"
<< f.str() << "\n";
else
printMsg_(level, f);
nest = true;
nestingLevel++;
}
}
void Nest::close()
{
if (nest) {
nestingLevel--;
if (logType == ltEscapes)
std::cerr << "\033[q";
nest = false;
}
}
void printMsg_(Verbosity level, const format & f)
{
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 % f.str()).str();
writeToStderr(s);
}
void warnOnce(bool & haveWarned, const format & f)
{
if (!haveWarned) {
printMsg(lvlError, format("warning: %1%") % f.str());
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 a AutoCloseFD isn't allowed (who should get to close
it?). But as a 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)
{
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) {
if (kill(-1, SIGKILL) == 0) break;
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");
}
void setuidCleanup()
{
/* Don't trust the environment. */
environ = 0;
/* Make sure that file descriptors 0, 1, 2 are open. */
for (int fd = 0; fd <= 2; ++fd) {
struct stat st;
if (fstat(fd, &st) == -1) abort();
}
}
#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;
}
string int2String(int n)
{
std::ostringstream str;
str << n;
return str.str();
}
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());
}
}
}
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