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find-runtime-roots: fold into gc.cc

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This commit is contained in:
Shea Levy 2016-07-20 14:00:36 -04:00
parent 06068b353d
commit 3c46fe62b8
4 changed files with 110 additions and 88 deletions
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3
.gitignore vendored
View file

@ -60,6 +60,7 @@ Makefile.config
# /src/libstore/
/src/libstore/schema.sql.hh
/src/libstore/sandbox-defaults.sb
# /src/nix-env/
/src/nix-env/nix-env
@ -94,6 +95,8 @@ Makefile.config
/misc/systemd/nix-daemon.socket
/misc/upstart/nix-daemon.conf
inst/
*.a
*.o
*.so

79
scripts/find-runtime-roots.pl.in
View file

@ -1,79 +0,0 @@
#! @perl@ -w @perlFlags@
use strict;
use Nix::Utils;
use Nix::Config;
sub readProc {
return unless -d "/proc";
opendir DIR, "/proc" or return;
foreach my $name (readdir DIR) {
next unless $name =~ /^\d+$/;
my $process = "/proc/$name";
#print STDERR "=== $process\n";
my $target;
print "$target\n" if $target = readlink "$process/exe";
print "$target\n" if $target = readlink "$process/cwd";
if (opendir FDS, "$process/fd") {
foreach my $name (readdir FDS) {
$target = readlink "$process/fd/$name";
print "$target\n" if $target && substr($target, 0, 1) eq "/";
}
closedir FDS;
}
if (open MAP, "<$process/maps") {
while (<MAP>) {
next unless /^ \s* \S+ \s+ \S+ \s+ \S+ \s+ \S+ \s+ \S+ \s+ (\/\S+) \s* $/x;
print "$1\n";
}
close MAP;
}
# Get all store paths that appear in the environment of this process.
eval {
my $env = Nix::Utils::readFile "$process/environ";
my @matches = $env =~ /\Q$Nix::Config::storeDir\E\/[0-9a-z]+[0-9a-zA-Z\+\-\._\?=]*/g;
print "$_\n" foreach @matches;
}
}
closedir DIR;
}
sub lsof {
return unless open LSOF, "lsof -n -w -F n 2> /dev/null |";
while (<LSOF>) {
next unless /^n (\/ .*)$/x;
print $1, "\n";
}
close LSOF;
}
readProc;
lsof;
sub printFile {
my ($fn) = @_;
if (-e $fn) {
print Nix::Utils::readFile($fn), "\n";
}
}
# This is rather NixOS-specific, so it probably shouldn't be here.
printFile "/proc/sys/kernel/modprobe";
printFile "/proc/sys/kernel/fbsplash";
printFile "/proc/sys/kernel/poweroff_cmd";

2
scripts/local.mk
View file

@ -9,7 +9,6 @@ bin-scripts += $(nix_bin_scripts)
nix_noinst_scripts := \
$(d)/build-remote.pl \
$(d)/find-runtime-roots.pl \
$(d)/resolve-system-dependencies.pl \
$(d)/nix-http-export.cgi \
$(d)/nix-profile.sh \
@ -20,7 +19,6 @@ noinst-scripts += $(nix_noinst_scripts)
profiledir = $(sysconfdir)/profile.d
$(eval $(call install-file-as, $(d)/nix-profile.sh, $(profiledir)/nix.sh, 0644))
$(eval $(call install-program-in, $(d)/find-runtime-roots.pl, $(libexecdir)/nix))
$(eval $(call install-program-in, $(d)/build-remote.pl, $(libexecdir)/nix))
$(eval $(call install-program-in, $(d)/resolve-system-dependencies.pl, $(libexecdir)/nix))
$(eval $(call install-symlink, nix-build, $(bindir)/nix-shell))

114
src/libstore/gc.cc
View file

@ -5,13 +5,14 @@
#include <functional>
#include <queue>
#include <algorithm>
#include <regex>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <climits>
namespace nix {
@ -330,18 +331,117 @@ Roots LocalStore::findRoots()
}
static void readProcLink(const string & file, StringSet & paths)
{
/* 64 is the starting buffer size gnu readlink uses... */
auto bufsiz = ssize_t{64};
try_again:
char buf[bufsiz];
auto res = readlink(file.c_str(), buf, bufsiz);
if (res == -1) {
if (errno == ENOENT || errno == EACCES)
return;
throw SysError("reading symlink");
}
if (res == bufsiz) {
if (SSIZE_MAX / 2 < bufsiz)
throw Error("stupidly long symlink");
bufsiz *= 2;
goto try_again;
}
if (res > 0 && buf[0] == '/')
paths.emplace(static_cast<char *>(buf), res);
return;
}
static string quoteRegexChars(const string & raw)
{
static auto specialRegex = std::regex(R"([.^$\\*+?()\[\]{}|])");
return std::regex_replace(raw, specialRegex, R"(\$&)");
}
static void readFileRoots(const char * path, StringSet & paths)
{
try {
paths.emplace(readFile(path));
} catch (SysError & e) {
if (e.errNo != ENOENT && e.errNo != EACCES)
throw;
}
}
void LocalStore::findRuntimeRoots(PathSet & roots)
{
Path rootFinder = getEnv("NIX_ROOT_FINDER",
settings.nixLibexecDir + "/nix/find-runtime-roots.pl");
StringSet paths;
auto procDir = AutoCloseDir{opendir("/proc")};
if (procDir) {
struct dirent * ent;
auto digitsRegex = std::regex(R"(^\d+$)");
auto mapRegex = std::regex(R"(^\s*\S+\s+\S+\s+\S+\s+\S+\s+\S+\s+(/\S+)\s*$)");
auto storePathRegex = std::regex(quoteRegexChars(storeDir) + R"(/[0-9a-z]+[0-9a-zA-Z\+\-\._\?=]*)");
while (errno = 0, ent = readdir(procDir)) {
checkInterrupt();
if (std::regex_match(ent->d_name, digitsRegex)) {
readProcLink((format("/proc/%1%/exe") % ent->d_name).str(), paths);
readProcLink((format("/proc/%1%/cwd") % ent->d_name).str(), paths);
if (rootFinder.empty()) return;
auto fdStr = (format("/proc/%1%/fd") % ent->d_name).str();
auto fdDir = AutoCloseDir(opendir(fdStr.c_str()));
if (!fdDir) {
if (errno == ENOENT || errno == EACCES)
continue;
throw SysError(format("opening %1%") % fdStr);
}
struct dirent * fd_ent;
while (errno = 0, fd_ent = readdir(fdDir)) {
if (fd_ent->d_name[0] != '.') {
readProcLink((format("%1%/%2%") % fdStr % fd_ent->d_name).str(), paths);
}
}
if (errno)
throw SysError(format("iterating /proc/%1%/fd") % ent->d_name);
fdDir.close();
debug(format("executing ‘%1%’ to find additional roots") % rootFinder);
auto mapLines =
tokenizeString<std::vector<string>>(readFile((format("/proc/%1%/maps") % ent->d_name).str(), true), "\n");
for (const auto& line : mapLines) {
auto match = std::smatch{};
if (std::regex_match(line, match, mapRegex))
paths.emplace(match[1]);
}
string result = runProgram(rootFinder);
try {
auto envString = readFile((format("/proc/%1%/environ") % ent->d_name).str(), true);
auto env_end = std::sregex_iterator{};
for (auto i = std::sregex_iterator{envString.begin(), envString.end(), storePathRegex}; i != env_end; ++i)
paths.emplace(i->str());
} catch (SysError & e) {
if (errno == ENOENT || errno == EACCES)
continue;
throw;
}
}
}
if (errno)
throw SysError("iterating /proc");
}
StringSet paths = tokenizeString<StringSet>(result, "\n");
try {
auto lsofRegex = std::regex(R"(^n(/.*)$)");
auto lsofLines =
tokenizeString<std::vector<string>>(runProgram("lsof", true, { "-n", "-w", "-F", "n" }), "\n");
for (const auto & line : lsofLines) {
auto match = std::smatch{};
if (std::regex_match(line, match, lsofRegex))
paths.emplace(match[1]);
}
} catch (ExecError & e) {
/* lsof not installed, lsof failed */
}
readFileRoots("/proc/sys/kernel/modprobe", paths);
readFileRoots("/proc/sys/kernel/fbsplash", paths);
readFileRoots("/proc/sys/kernel/poweroff_cmd", paths);
for (auto & i : paths)
if (isInStore(i)) {