lix/src/libmain/shared.cc
Eelco Dolstra a562d544d8 When ‘--help’ is given, just run ‘man’ to show the manual page
I.e. do what git does.  I'm too lazy to keep the builtin help text up
to date :-)

Also add ‘--help’ to various commands that lacked it
(e.g. nix-collect-garbage).
2012-10-03 16:40:09 -04:00

352 lines
10 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>
#if HAVE_BOEHMGC
#include <gc/gc.h>
#endif
namespace nix {
volatile sig_atomic_t blockInt = 0;
static void sigintHandler(int signo)
{
if (!blockInt) {
_isInterrupted = 1;
blockInt = 1;
}
}
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(StoreAPI & store, const PathSet & paths)
{
unsigned long long downloadSize, narSize;
PathSet willBuild, willSubstitute, unknown;
queryMissing(store, paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
if (!willBuild.empty()) {
printMsg(lvlInfo, format("these derivations will be built:"));
foreach (PathSet::iterator, i, willBuild)
printMsg(lvlInfo, format(" %1%") % *i);
}
if (!willSubstitute.empty()) {
printMsg(lvlInfo, format("these paths will be fetched (%.2f MiB download, %.2f MiB unpacked):")
% (downloadSize / (1024.0 * 1024.0))
% (narSize / (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 these paths%1%:")
% (settings.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");
}
static bool showTrace = false;
string getArg(const string & opt,
Strings::iterator & i, const Strings::iterator & end)
{
++i;
if (i == end) throw UsageError(format("`%1%' requires an argument") % opt);
return *i;
}
/* Initialize and reorder arguments, then call the actual argument
processor. */
static void initAndRun(int argc, char * * argv)
{
settings.processEnvironment();
settings.loadConfFile();
/* Catch SIGINT. */
struct sigaction act;
act.sa_handler = sigintHandler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGINT, &act, 0))
throw SysError("installing handler for SIGINT");
if (sigaction(SIGTERM, &act, 0))
throw SysError("installing handler for SIGTERM");
if (sigaction(SIGHUP, &act, 0))
throw SysError("installing handler for SIGHUP");
/* Ignore SIGPIPE. */
act.sa_handler = SIG_IGN;
act.sa_flags = 0;
if (sigaction(SIGPIPE, &act, 0))
throw SysError("ignoring SIGPIPE");
/* Reset SIGCHLD to its default. */
act.sa_handler = SIG_DFL;
act.sa_flags = 0;
if (sigaction(SIGCHLD, &act, 0))
throw SysError("resetting SIGCHLD");
/* 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);
/* 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 (arg.length() > 2 && arg[0] == '-' && arg[1] != '-' && !isdigit(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. */
int verbosityDelta = lvlInfo;
for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
string arg = *i;
if (arg == "--verbose" || arg == "-v") verbosityDelta++;
else if (arg == "--quiet") verbosityDelta--;
else if (arg == "--log-type") {
string s = getArg(arg, i, args.end());
setLogType(s);
}
else if (arg == "--no-build-output" || arg == "-Q")
settings.buildVerbosity = lvlVomit;
else if (arg == "--print-build-trace")
settings.printBuildTrace = true;
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")
settings.keepFailed = true;
else if (arg == "--keep-going" || arg == "-k")
settings.keepGoing = true;
else if (arg == "--fallback")
settings.set("build-fallback", "true");
else if (arg == "--max-jobs" || arg == "-j")
settings.set("build-max-jobs", getArg(arg, i, args.end()));
else if (arg == "--cores")
settings.set("build-cores", getArg(arg, i, args.end()));
else if (arg == "--readonly-mode")
settings.readOnlyMode = true;
else if (arg == "--max-silent-time")
settings.set("build-max-silent-time", getArg(arg, i, args.end()));
else if (arg == "--timeout")
settings.set("build-timeout", getArg(arg, i, args.end()));
else if (arg == "--no-build-hook")
settings.useBuildHook = false;
else if (arg == "--show-trace")
showTrace = true;
else if (arg == "--option") {
++i; if (i == args.end()) throw UsageError("`--option' requires two arguments");
string name = *i;
++i; if (i == args.end()) throw UsageError("`--option' requires two arguments");
string value = *i;
settings.set(name, value);
}
else remaining.push_back(arg);
}
verbosity = (Verbosity) (verbosityDelta < 0 ? 0 : verbosityDelta);
settings.update();
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;
}
/* Called when the Boehm GC runs out of memory. */
static void * oomHandler(size_t requested)
{
/* Convert this to a proper C++ exception. */
throw std::bad_alloc();
}
void showManPage(const string & name)
{
string cmd = "man " + name;
if (system(cmd.c_str()) != 0)
throw Error(format("command `%1%' failed") % cmd);
}
int exitCode = 0;
char * * argvSaved = 0;
}
static char buf[1024];
int main(int argc, char * * argv)
{
using namespace nix;
argvSaved = argv;
/* If we're setuid, then we need to take some security precautions
right away. */
if (argc == 0) abort();
setuidInit();
/* Turn on buffering for cerr. */
#if HAVE_PUBSETBUF
std::cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));
#endif
std::ios::sync_with_stdio(false);
#if HAVE_BOEHMGC
/* Initialise the Boehm garbage collector. This isn't necessary
on most platforms, but for portability we do it anyway. */
GC_INIT();
GC_oom_fn = oomHandler;
#endif
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%%2%") % (showTrace ? e.prefix() : "") % e.msg());
if (e.prefix() != "" && !showTrace)
printMsg(lvlError, "(use `--show-trace' to show detailed location information)");
return e.status;
} catch (std::exception & e) {
printMsg(lvlError, format("error: %1%") % e.what());
return 1;
}
return exitCode;
}