guix/src/libmain/shared.cc

287 lines
8.2 KiB
C++

#include <iostream>
#include <cctype>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
extern "C" {
#include <aterm2.h>
}
#include "globals.hh"
#include "shared.hh"
#include "config.h"
volatile sig_atomic_t blockInt = 0;
void sigintHandler(int signo)
{
if (!blockInt) {
_isInterrupted = 1;
blockInt = 1;
}
}
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");
}
void checkStoreNotSymlink(Path path)
{
struct stat st;
while (path.size()) {
if (lstat(path.c_str(), &st))
throw SysError(format("getting status of `%1%'") % path);
if (S_ISLNK(st.st_mode))
throw Error(format(
"the path `%1%' is a symlink; "
"this is not allowed for the Nix store and its parent directories")
% path);
path = dirOf(path);
}
}
/* 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 = getEnv("NIX_STORE_DIR", canonPath(NIX_STORE_DIR));
nixDataDir = getEnv("NIX_DATA_DIR", canonPath(NIX_DATA_DIR));
nixLogDir = getEnv("NIX_LOG_DIR", canonPath(NIX_LOG_DIR));
nixStateDir = getEnv("NIX_STATE_DIR", canonPath(NIX_STATE_DIR));
nixDBPath = getEnv("NIX_DB_DIR", nixStateDir + "/db");
/* Check that the store directory and its parent are not
symlinks. */
if (getEnv("NIX_IGNORE_SYMLINK_STORE") != "1")
checkStoreNotSymlink(nixStore);
/* 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");
/* Ignore SIGPIPE. */
act.sa_handler = SIG_IGN;
act.sa_flags = 0;
if (sigaction(SIGPIPE, &act, &oact))
throw SysError("ignoring SIGPIPE");
/* 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 (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") {
cout << format("%1% (Nix) %2%") % programId % NIX_VERSION << 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") {
++i;
if (i == args.end()) throw UsageError("`--max-jobs' requires an argument");
istringstream str(*i);
int n;
str >> n;
if (!str || !str.eof() || n < 0)
throw UsageError(format("`--max-jobs' requires a non-negative integer"));
maxBuildJobs = n;
}
else remaining.push_back(arg);
}
run(remaining);
}
void switchToNixUser()
{
#if SETUID_HACK
/* Here we set the uid and gid to the Nix user and group,
respectively, IF the current (real) user is a member of the Nix
group. Otherwise we just drop all privileges. */
/* Lookup the Nix gid. */
struct group * gr = getgrnam(NIX_GROUP);
if (!gr) {
cerr << format("missing group `%1%'\n") % NIX_GROUP;
exit(1);
}
/* Get the supplementary group IDs for the current user. */
int maxGids = 512, nrGids;
gid_t gids[maxGids];
if ((nrGids = getgroups(maxGids, gids)) == -1) {
cerr << format("unable to query gids\n");
exit(1);
}
/* Check that the current user is a member of the Nix group. */
bool found = false;
for (int i = 0; i < nrGids; ++i)
if (gids[i] == gr->gr_gid) {
found = true;
break;
}
if (!found) {
/* Not in the Nix group - drop all root/Nix privileges. */
setgid(getgid());
setuid(getuid());
return;
}
/* Set the real, effective and saved gids to gr->gr_gid. Also
make very sure that this succeeded. We switch the gid first
because we cannot do it after we have dropped root uid. */
if (setgid(gr->gr_gid) != 0 ||
getgid() != gr->gr_gid ||
getegid() != gr->gr_gid)
{
cerr << format("unable to set gid to `%1%'\n") % NIX_GROUP;
exit(1);
}
/* Lookup the Nix uid. */
struct passwd * pw = getpwnam(NIX_USER);
if (!pw) {
cerr << format("missing user `%1%'\n") % NIX_USER;
exit(1);
}
/* This will drop all root privileges, setting the real, effective
and saved uids to pw->pw_uid. Also make very sure that this
succeeded.*/
if (setuid(pw->pw_uid) != 0 ||
getuid() != pw->pw_uid ||
geteuid() != pw->pw_uid)
{
cerr << format("unable to set uid to `%1%'\n") % NIX_USER;
exit(1);
}
#endif
}
static char buf[1024];
int main(int argc, char * * argv)
{
/* If we are setuid root, we have to get rid of the excess
privileges ASAP. */
printMsg(lvlError, format("%1% %2% %3% %4%\n") % getuid() % geteuid()
% getgid() % getegid());
switchToNixUser();
printMsg(lvlError, format("%1% %2% %3% %4%\n") % getuid() % geteuid()
% getgid() % getegid());
/* ATerm setup. */
ATerm bottomOfStack;
ATinit(argc, argv, &bottomOfStack);
/* Turn on buffering for cerr. */
#if HAVE_PUBSETBUF
cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));
#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 (Error & e) {
printMsg(lvlError, format("error: %1%") % e.msg());
return 1;
} catch (exception & e) {
printMsg(lvlError, format("error: %1%") % e.what());
return 1;
}
return 0;
}