lix/src/libmain/shared.cc
Eelco Dolstra 709b55ee02 * Put the chroots under /nix/var/nix/chroots to reduce the risk of
disasters involving `rm -rf' on bind mounts.  Will try the
  definitive fix (per-process mounts, apparently possible via the
  CLONE_NEWNS flag in clone()) some other time.
2008-10-29 15:34:48 +00:00

371 lines
11 KiB
C++

#include "config.h"
#include "shared.hh"
#include "globals.hh"
#include "store-api.hh"
#include "util.hh"
#include "misc.hh"
#include <iostream>
#include <cctype>
#include <exception>
#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");
}
void printMissing(const PathSet & paths)
{
unsigned long long downloadSize;
PathSet willBuild, willSubstitute, unknown;
queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize);
if (!willBuild.empty()) {
printMsg(lvlInfo, format("the following derivations will be built:"));
foreach (PathSet::iterator, i, willBuild)
printMsg(lvlInfo, format(" %1%") % *i);
}
if (!willSubstitute.empty()) {
printMsg(lvlInfo, format("the following paths will be downloaded/copied (%.2f MiB):") %
(downloadSize / (1024.0 * 1024.0)));
foreach (PathSet::iterator, i, willSubstitute)
printMsg(lvlInfo, format(" %1%") % *i);
}
if (!unknown.empty()) {
printMsg(lvlInfo, format("don't know how to build the following paths%1%:")
% (readOnlyMode ? " (may be caused by read-only store access)" : ""));
foreach (PathSet::iterator, i, unknown)
printMsg(lvlInfo, format(" %1%") % *i);
}
}
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");
}
unsigned long long getIntArg(const string & opt,
Strings::iterator & i, const Strings::iterator & end)
{
++i;
if (i == end) throw UsageError(format("`%1%' requires an argument") % opt);
long long n;
if (!string2Int(*i, n) || n < 0)
throw UsageError(format("`%1%' requires a non-negative integer") % opt);
return n;
}
void initDerivationsHelpers();
static void closeStore()
{
try {
throw;
} catch (std::exception & e) {
printMsg(lvlError,
format("FATAL: unexpected exception (closing store and aborting): %1%") % e.what());
}
try {
store.reset((StoreAPI *) 0);
} catch (...) {
ignoreException();
}
abort();
}
RemoveTempRoots::~RemoveTempRoots()
{
removeTempRoots();
}
/* Initialize and reorder arguments, then call the actual argument
processor. */
static void initAndRun(int argc, char * * argv)
{
/* 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));
nixChrootsDir = canonPath(getEnv("NIX_CHROOTS_DIR", nixStateDir + "/chroots"));
string subs = getEnv("NIX_SUBSTITUTERS", "default");
if (subs == "default") {
substituters.push_back(nixLibexecDir + "/nix/substituters/copy-from-other-stores.pl");
substituters.push_back(nixLibexecDir + "/nix/substituters/download-using-manifests.pl");
} else
substituters = tokenizeString(subs, ":");
/* 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 if (arg == "--no-build-hook")
useBuildHook = false;
else remaining.push_back(arg);
}
/* Automatically clean up the temporary roots file when we
exit. */
RemoveTempRoots removeTempRoots __attribute__((unused));
/* Make sure that the database gets closed properly, even if
terminate() is called (which happens sometimes due to bugs in
destructor/exceptions interaction, but that needn't preclude a
clean shutdown of the database). */
std::set_terminate(closeStore);
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 (BaseError & 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;
}