lix/src/libmain/shared.cc
Eelco Dolstra 9dbfe242e3 * Kill a build if it has gone for more than a certain number of
seconds without producing output on stdout or stderr (NIX-65).  This
  timeout can be specified using the `--max-silent-time' option or the
  `build-max-silent-time' configuration setting.  The default is
  infinity (0).

* Fix a tricky race condition: if we kill the build user before the
  child has done its setuid() to the build user uid, then it won't be
  killed, and we'll potentially lock up in pid.wait().  So also send a
  conventional kill to the child.
2006-12-08 15:44:00 +00:00

317 lines
9.1 KiB
C++

#include "shared.hh"
#include "globals.hh"
#include "store-api.hh"
#include "util.hh"
#include "config.h"
#include <iostream>
#include <cctype>
#include <sys/stat.h>
#include <unistd.h>
#include <aterm2.h>
namespace nix {
volatile sig_atomic_t blockInt = 0;
static void sigintHandler(int signo)
{
if (!blockInt) {
_isInterrupted = 1;
blockInt = 1;
}
}
Path makeRootName(const Path & gcRoot, int & counter)
{
counter++;
if (counter == 1)
return gcRoot;
else
return (format("%1%-%2%") % gcRoot % counter).str();
}
void printGCWarning()
{
static bool haveWarned = false;
warnOnce(haveWarned,
"you did not specify `--add-root'; "
"the result might be removed by the garbage collector");
}
static void setLogType(string lt)
{
if (lt == "pretty") logType = ltPretty;
else if (lt == "escapes") logType = ltEscapes;
else if (lt == "flat") logType = ltFlat;
else throw UsageError("unknown log type");
}
static unsigned int getIntArg(const string & opt,
Strings::iterator & i, const Strings::iterator & end)
{
++i;
if (i == end) throw UsageError(format("`%1%' requires an argument") % opt);
int n;
if (!string2Int(*i, n) || n < 0)
throw UsageError(format("`%1%' requires a non-negative integer") % opt);
return n;
}
struct RemoveTempRoots
{
~RemoveTempRoots()
{
removeTempRoots();
}
};
void initDerivationsHelpers();
/* Initialize and reorder arguments, then call the actual argument
processor. */
static void initAndRun(int argc, char * * argv)
{
string root = getEnv("NIX_ROOT");
if (root != "") {
if (chroot(root.c_str()) != 0)
throw SysError(format("changing root to `%1%'") % root);
}
/* Setup Nix paths. */
nixStore = canonPath(getEnv("NIX_STORE_DIR", getEnv("NIX_STORE", NIX_STORE_DIR)));
nixDataDir = canonPath(getEnv("NIX_DATA_DIR", NIX_DATA_DIR));
nixLogDir = canonPath(getEnv("NIX_LOG_DIR", NIX_LOG_DIR));
nixStateDir = canonPath(getEnv("NIX_STATE_DIR", NIX_STATE_DIR));
nixDBPath = getEnv("NIX_DB_DIR", nixStateDir + "/db");
nixConfDir = canonPath(getEnv("NIX_CONF_DIR", NIX_CONF_DIR));
nixLibexecDir = canonPath(getEnv("NIX_LIBEXEC_DIR", NIX_LIBEXEC_DIR));
nixBinDir = canonPath(getEnv("NIX_BIN_DIR", NIX_BIN_DIR));
/* Get some settings from the configuration file. */
thisSystem = querySetting("system", SYSTEM);
maxBuildJobs = queryIntSetting("build-max-jobs", 1);
maxSilentTime = queryIntSetting("build-max-silent-time", 0);
/* Catch SIGINT. */
struct sigaction act, oact;
act.sa_handler = sigintHandler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGINT, &act, &oact))
throw SysError("installing handler for SIGINT");
if (sigaction(SIGTERM, &act, &oact))
throw SysError("installing handler for SIGTERM");
if (sigaction(SIGHUP, &act, &oact))
throw SysError("installing handler for SIGHUP");
/* Ignore SIGPIPE. */
act.sa_handler = SIG_IGN;
act.sa_flags = 0;
if (sigaction(SIGPIPE, &act, &oact))
throw SysError("ignoring SIGPIPE");
/* There is no privacy in the Nix system ;-) At least not for
now. In particular, store objects should be readable by
everybody. This prevents nasty surprises when using a shared
store (with the setuid() hack). */
umask(0022);
/* Process the NIX_LOG_TYPE environment variable. */
string lt = getEnv("NIX_LOG_TYPE");
if (lt != "") setLogType(lt);
/* ATerm stuff. !!! find a better place to put this */
initDerivationsHelpers();
/* Put the arguments in a vector. */
Strings args, remaining;
while (argc--) args.push_back(*argv++);
args.erase(args.begin());
/* Expand compound dash options (i.e., `-qlf' -> `-q -l -f'), and
ignore options for the ATerm library. */
for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
string arg = *i;
if (string(arg, 0, 4) == "-at-") ;
else if (arg.length() > 2 && arg[0] == '-' && arg[1] != '-') {
for (unsigned int j = 1; j < arg.length(); j++)
if (isalpha(arg[j]))
remaining.push_back((string) "-" + arg[j]);
else {
remaining.push_back(string(arg, j));
break;
}
} else remaining.push_back(arg);
}
args = remaining;
remaining.clear();
/* Process default options. */
for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
string arg = *i;
if (arg == "--verbose" || arg == "-v")
verbosity = (Verbosity) ((int) verbosity + 1);
else if (arg == "--log-type") {
++i;
if (i == args.end()) throw UsageError("`--log-type' requires an argument");
setLogType(*i);
}
else if (arg == "--build-output" || arg == "-B")
; /* !!! obsolete - remove eventually */
else if (arg == "--no-build-output" || arg == "-Q")
buildVerbosity = lvlVomit;
else if (arg == "--help") {
printHelp();
return;
}
else if (arg == "--version") {
std::cout << format("%1% (Nix) %2%") % programId % NIX_VERSION << std::endl;
return;
}
else if (arg == "--keep-failed" || arg == "-K")
keepFailed = true;
else if (arg == "--keep-going" || arg == "-k")
keepGoing = true;
else if (arg == "--fallback")
tryFallback = true;
else if (arg == "--max-jobs" || arg == "-j")
maxBuildJobs = getIntArg(arg, i, args.end());
else if (arg == "--readonly-mode")
readOnlyMode = true;
else if (arg == "--max-silent-time")
maxSilentTime = getIntArg(arg, i, args.end());
else remaining.push_back(arg);
}
/* Automatically clean up the temporary roots file when we
exit. */
RemoveTempRoots removeTempRoots; /* unused variable - don't remove */
run(remaining);
/* Close the Nix database. */
store.reset((StoreAPI *) 0);
}
bool setuidMode = false;
static void setuidInit()
{
/* Don't do anything if this is not a setuid binary. */
if (getuid() == geteuid() && getgid() == getegid()) return;
uid_t nixUid = geteuid();
gid_t nixGid = getegid();
setuidCleanup();
/* Don't trust the current directory. */
if (chdir("/") == -1) abort();
/* Set the real (and preferably also the save) uid/gid to the
effective uid/gid. This matters mostly when we're not using
build-users (bad!), since some builders (like Perl) complain
when real != effective.
On systems where setresuid is unavailable, we can't drop the
saved uid/gid. This means that we could go back to the
original real uid (i.e., the uid of the caller). That's not
really a problem, except maybe when we execute a builder and
we're not using build-users. In that case, the builder may be
able to switch to the uid of the caller and possibly do bad
stuff. But note that when not using build-users, the builder
could also modify the Nix executables (say, replace them by a
Trojan horse), so the problem is already there. */
#if HAVE_SETRESUID
if (setresuid(nixUid, nixUid, nixUid)) abort();
if (setresgid(nixGid, nixGid, nixGid)) abort();
#elif HAVE_SETREUID
/* Note: doesn't set saved uid/gid! */
fprintf(stderr, "warning: cannot set saved uid\n");
if (setreuid(nixUid, nixUid)) abort();
if (setregid(nixGid, nixGid)) abort();
#else
/* Note: doesn't set real and saved uid/gid! */
fprintf(stderr, "warning: cannot set real and saved uids\n");
if (setuid(nixUid)) abort();
if (setgid(nixGid)) abort();
#endif
setuidMode = true;
}
}
static char buf[1024];
int main(int argc, char * * argv)
{
using namespace nix;
/* If we're setuid, then we need to take some security precautions
right away. */
if (argc == 0) abort();
setuidInit();
/* ATerm setup. */
ATerm bottomOfStack;
ATinit(argc, argv, &bottomOfStack);
/* Turn on buffering for cerr. */
#if HAVE_PUBSETBUF
std::cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));
#endif
std::ios::sync_with_stdio(false);
try {
try {
initAndRun(argc, argv);
} catch (...) {
/* Subtle: we have to make sure that any `interrupted'
condition is discharged before we reach printMsg()
below, since otherwise it will throw an (uncaught)
exception. */
blockInt = 1; /* ignore further SIGINTs */
_isInterrupted = 0;
throw;
}
} catch (UsageError & e) {
printMsg(lvlError,
format(
"error: %1%\n"
"Try `%2% --help' for more information.")
% e.what() % programId);
return 1;
} catch (Error & e) {
printMsg(lvlError, format("error: %1%") % e.msg());
return 1;
} catch (std::exception & e) {
printMsg(lvlError, format("error: %1%") % e.what());
return 1;
}
return 0;
}