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Diffstat (limited to '')
| -rw-r--r-- | methods/mirror.cc | 406 |
1 files changed, 406 insertions, 0 deletions
diff --git a/methods/mirror.cc b/methods/mirror.cc new file mode 100644 index 0000000..add9f08 --- /dev/null +++ b/methods/mirror.cc @@ -0,0 +1,406 @@ +// -*- mode: cpp; mode: fold -*- +// Description /*{{{*/ +/* ###################################################################### + + Mirror URI – This method helps avoiding hardcoding of mirrors in the + sources.lists by looking up a list of mirrors first to which the + following requests are redirected. + + ##################################################################### */ + /*}}}*/ +// Include Files /*{{{*/ +#include <config.h> + +#include "aptmethod.h" +#include <apt-pkg/configuration.h> +#include <apt-pkg/error.h> +#include <apt-pkg/fileutl.h> +#include <apt-pkg/metaindex.h> +#include <apt-pkg/sourcelist.h> +#include <apt-pkg/strutl.h> + +#include <functional> +#include <random> +#include <string> +#include <unordered_map> + +#include <sys/utsname.h> + +#include <apti18n.h> + /*}}}*/ +constexpr char const *const disallowLocal[] = {"ftp", "http", "https"}; + +static void sortByLength(std::vector<std::string> &vec) /*{{{*/ +{ + // this ensures having mirror://foo/ and mirror://foo/bar/ works as expected + // by checking for the longest matches first + std::sort(vec.begin(), vec.end(), [](std::string const &a, std::string const &b) { + return a.length() > b.length(); + }); +} + /*}}}*/ +class MirrorMethod : public aptMethod /*{{{*/ +{ + std::mt19937 genrng; + std::vector<std::string> sourceslist; + std::unordered_map<std::string, std::string> msgCache; + enum MirrorFileState + { + REQUESTED, + FAILED, + AVAILABLE + }; + struct MirrorInfo + { + std::string uri; + unsigned long priority = std::numeric_limits<decltype(priority)>::max(); + decltype(genrng)::result_type seed = 0; + std::unordered_map<std::string, std::vector<std::string>> tags; + MirrorInfo(std::string const &u, std::vector<std::string> &&ptags = {}) : uri(u) + { + for (auto &&tag : ptags) + { + auto const colonfound = tag.find(':'); + if (unlikely(colonfound == std::string::npos)) + continue; + auto name = tag.substr(0, colonfound); + auto value = tag.substr(colonfound + 1); + if (name == "arch") + tags["Architecture"].emplace_back(std::move(value)); + else if (name == "lang") + tags["Language"].emplace_back(std::move(value)); + else if (name == "priority") + priority = std::strtoul(value.c_str(), nullptr, 10); + else if (likely(name.empty() == false)) + { + if (name == "codename" || name == "suite") + tags["Release"].push_back(value); + name[0] = std::toupper(name[0]); + tags[std::move(name)].emplace_back(std::move(value)); + } + } + } + }; + struct MirrorListInfo + { + MirrorFileState state; + std::string baseuri; + std::vector<MirrorInfo> list; + }; + std::unordered_map<std::string, MirrorListInfo> mirrorfilestate; + + virtual bool URIAcquire(std::string const &Message, FetchItem *Itm) APT_OVERRIDE; + + void RedirectItem(MirrorListInfo const &info, FetchItem *const Itm, std::string const &Message); + bool MirrorListFileRecieved(MirrorListInfo &info, FetchItem *const Itm); + std::string GetMirrorFileURI(std::string const &Message, FetchItem *const Itm); + void DealWithPendingItems(std::vector<std::string> const &baseuris, MirrorListInfo const &info, FetchItem *const Itm, std::function<void()> handler); + + public: + MirrorMethod(std::string &&pProg) : aptMethod(std::move(pProg), "2.0", SingleInstance | Pipeline | SendConfig | AuxRequests), genrng(clock()) + { + SeccompFlags = aptMethod::BASE | aptMethod::DIRECTORY; + } +}; + /*}}}*/ +void MirrorMethod::RedirectItem(MirrorListInfo const &info, FetchItem *const Itm, std::string const &Message) /*{{{*/ +{ + std::unordered_map<std::string, std::string> matchers; + matchers.emplace("Architecture", LookupTag(Message, "Target-Architecture")); + matchers.emplace("Codename", LookupTag(Message, "Target-Codename")); + matchers.emplace("Component", LookupTag(Message, "Target-Component")); + matchers.emplace("Language", LookupTag(Message, "Target-Language")); + matchers.emplace("Release", LookupTag(Message, "Target-Release")); + matchers.emplace("Suite", LookupTag(Message, "Target-Suite")); + matchers.emplace("Type", LookupTag(Message, "Target-Type")); + decltype(info.list) possMirrors; + for (auto const &mirror : info.list) + { + bool failedMatch = false; + for (auto const &m : matchers) + { + if (m.second.empty()) + continue; + auto const tagsetiter = mirror.tags.find(m.first); + if (tagsetiter == mirror.tags.end()) + continue; + auto const tagset = tagsetiter->second; + if (tagset.empty() == false && std::find(tagset.begin(), tagset.end(), m.second) == tagset.end()) + { + failedMatch = true; + break; + } + } + if (failedMatch) + continue; + possMirrors.push_back(mirror); + } + for (auto &&mirror : possMirrors) + mirror.seed = genrng(); + std::sort(possMirrors.begin(), possMirrors.end(), [](MirrorInfo const &a, MirrorInfo const &b) { + if (a.priority != b.priority) + return a.priority < b.priority; + return a.seed < b.seed; + }); + std::string const path = Itm->Uri.substr(info.baseuri.length()); + std::string altMirrors; + std::unordered_map<std::string, std::string> fields; + fields.emplace("URI", Queue->Uri); + for (auto curMirror = possMirrors.cbegin(); curMirror != possMirrors.cend(); ++curMirror) + { + std::string mirror = curMirror->uri; + if (APT::String::Endswith(mirror, "/") == false) + mirror.append("/"); + mirror.append(path); + if (curMirror == possMirrors.cbegin()) + fields.emplace("New-URI", mirror); + else if (altMirrors.empty()) + altMirrors.append(mirror); + else + altMirrors.append("\n").append(mirror); + } + fields.emplace("Alternate-URIs", altMirrors); + SendMessage("103 Redirect", std::move(fields)); + Dequeue(); +} + /*}}}*/ +void MirrorMethod::DealWithPendingItems(std::vector<std::string> const &baseuris, /*{{{*/ + MirrorListInfo const &info, FetchItem *const Itm, + std::function<void()> handler) +{ + FetchItem **LastItm = &Itm->Next; + while (*LastItm != nullptr) + LastItm = &((*LastItm)->Next); + while (Queue != Itm) + { + if (APT::String::Startswith(Queue->Uri, info.baseuri) == false || + std::any_of(baseuris.cbegin(), baseuris.cend(), [&](std::string const &b) { return APT::String::Startswith(Queue->Uri, b); })) + { + // move the item behind the aux file not related to it + *LastItm = Queue; + Queue = QueueBack = Queue->Next; + (*LastItm)->Next = nullptr; + LastItm = &((*LastItm)->Next); + } + else + { + handler(); + } + } + // now remove out trigger + QueueBack = Queue = Queue->Next; + delete Itm; +} + /*}}}*/ +bool MirrorMethod::MirrorListFileRecieved(MirrorListInfo &info, FetchItem *const Itm) /*{{{*/ +{ + std::vector<std::string> baseuris; + for (auto const &i : mirrorfilestate) + if (info.baseuri.length() < i.second.baseuri.length() && + i.second.state == REQUESTED && + APT::String::Startswith(i.second.baseuri, info.baseuri)) + baseuris.push_back(i.second.baseuri); + sortByLength(baseuris); + + FileFd mirrorlist; + if (FileExists(Itm->DestFile) && mirrorlist.Open(Itm->DestFile, FileFd::ReadOnly, FileFd::Extension)) + { + auto const accessColon = info.baseuri.find(':'); + auto access = info.baseuri.substr(0, accessColon); + std::string prefixAccess; + if (APT::String::Startswith(access, "mirror") == false) + { + auto const plus = info.baseuri.find('+'); + prefixAccess = info.baseuri.substr(0, plus); + access.erase(0, plus + 1); + } + std::vector<std::string> limitAccess; + // If the mirror file comes from an online source, allow only other online + // sources, not e.g. file:///. If the mirrorlist comes from there we can assume + // the admin knows what (s)he is doing through and not limit the options. + if (std::any_of(std::begin(disallowLocal), std::end(disallowLocal), + [&access](char const *const a) { return APT::String::Endswith(access, std::string("+") + a); }) || + access == "mirror") + { + for (auto const &a : disallowLocal) + limitAccess.emplace_back(a); + } + std::string line; + while (mirrorlist.ReadLine(line)) + { + if (line.empty() || line[0] == '#') + continue; + auto const access = line.substr(0, line.find(':')); + if (limitAccess.empty() == false && std::find(limitAccess.begin(), limitAccess.end(), access) == limitAccess.end()) + continue; + auto const tab = line.find('\t'); + if (tab == std::string::npos) + { + if (prefixAccess.empty()) + info.list.emplace_back(std::move(line)); + else + info.list.emplace_back(prefixAccess + '+' + line); + } + else + { + auto uri = line.substr(0, tab); + if (prefixAccess.empty() == false) + uri = prefixAccess + '+' + uri; + auto tagline = line.substr(tab + 1); + std::replace_if(tagline.begin(), tagline.end(), isspace_ascii, ' '); + auto tags = VectorizeString(tagline, ' '); + tags.erase(std::remove_if(tags.begin(), tags.end(), [](std::string const &a) { return a.empty(); }), tags.end()); + info.list.emplace_back(std::move(uri), std::move(tags)); + } + } + mirrorlist.Close(); + + if (info.list.empty()) + { + info.state = FAILED; + DealWithPendingItems(baseuris, info, Itm, [&]() { + std::string msg; + strprintf(msg, "Mirror list %s is empty for %s", Itm->DestFile.c_str(), Queue->Uri.c_str()); + Fail(msg, false); + }); + } + else + { + info.state = AVAILABLE; + DealWithPendingItems(baseuris, info, Itm, [&]() { + RedirectItem(info, Queue, msgCache[Queue->Uri]); + }); + msgCache.clear(); + } + } + else + { + info.state = FAILED; + DealWithPendingItems(baseuris, info, Itm, [&]() { + std::string msg; + strprintf(msg, "Downloading mirror file %s failed for %s", Itm->DestFile.c_str(), Queue->Uri.c_str()); + Fail(msg, false); + }); + } + return true; +} + /*}}}*/ +std::string MirrorMethod::GetMirrorFileURI(std::string const &Message, FetchItem *const Itm) /*{{{*/ +{ + if (APT::String::Startswith(Itm->Uri, Binary)) + { + std::string const repouri = LookupTag(Message, "Target-Repo-Uri"); + if (repouri.empty() == false && std::find(sourceslist.cbegin(), sourceslist.cend(), repouri) == sourceslist.cend()) + sourceslist.push_back(repouri); + } + if (sourceslist.empty()) + { + // read sources.list and find the matching base uri + pkgSourceList sl; + if (sl.ReadMainList() == false) + { + _error->Error(_("The list of sources could not be read.")); + return ""; + } + std::string const needle = Binary + ":"; + for (auto const &SL : sl) + { + std::string uristr = SL->GetURI(); + if (APT::String::Startswith(uristr, needle)) + sourceslist.push_back(uristr); + } + sortByLength(sourceslist); + } + for (auto uristr : sourceslist) + { + if (APT::String::Startswith(Itm->Uri, uristr)) + { + uristr.erase(uristr.length() - 1); // remove the ending '/' + auto const colon = uristr.find(':'); + if (unlikely(colon == std::string::npos)) + continue; + auto const plus = uristr.find("+"); + if (plus < colon) + { + // started as tor+mirror+http we want to get the file via tor+http + auto access = uristr.substr(0, colon); + std::string prefixAccess; + if (APT::String::Startswith(access, "mirror") == false) + { + prefixAccess = uristr.substr(0, plus); + access.erase(0, plus + 1); + uristr.erase(plus, strlen("mirror") + 1); + return uristr; + } + else + return uristr.substr(plus + 1); + } + else + { + uristr.replace(0, strlen("mirror"), "http"); + return uristr; + } + } + } + return ""; +} + /*}}}*/ +bool MirrorMethod::URIAcquire(std::string const &Message, FetchItem *Itm) /*{{{*/ +{ + auto mirrorinfo = mirrorfilestate.find(Itm->Uri); + if (mirrorinfo != mirrorfilestate.end()) + return MirrorListFileRecieved(mirrorinfo->second, Itm); + + std::string const mirrorfileuri = GetMirrorFileURI(Message, Itm); + if (mirrorfileuri.empty()) + { + _error->Error("Couldn't determine mirror list to query for %s", Itm->Uri.c_str()); + return false; + } + if (DebugEnabled()) + std::clog << "Mirror-URI: " << mirrorfileuri << " for " << Itm->Uri << std::endl; + + // have we requested this mirror file already? + auto const state = mirrorfilestate.find(mirrorfileuri); + if (state == mirrorfilestate.end()) + { + msgCache[Itm->Uri] = Message; + MirrorListInfo info; + info.state = REQUESTED; + info.baseuri = mirrorfileuri + '/'; + auto const colon = info.baseuri.find(':'); + if (unlikely(colon == std::string::npos)) + return false; + info.baseuri.replace(0, colon, Binary); + mirrorfilestate[mirrorfileuri] = info; + std::unordered_map<std::string, std::string> fields; + fields.emplace("URI", Itm->Uri); + fields.emplace("MaximumSize", std::to_string(1 * 1024 * 1024)); //FIXME: 1 MB is enough for everyone + fields.emplace("Aux-ShortDesc", "Mirrorlist"); + fields.emplace("Aux-Description", mirrorfileuri + " Mirrorlist"); + fields.emplace("Aux-Uri", mirrorfileuri); + SendMessage("351 Aux Request", std::move(fields)); + return true; + } + + switch (state->second.state) + { + case REQUESTED: + // lets wait for the requested mirror file + msgCache[Itm->Uri] = Message; + return true; + case FAILED: + Fail("Downloading mirror file failed", false); + return true; + case AVAILABLE: + RedirectItem(state->second, Itm, Message); + return true; + } + return false; +} + /*}}}*/ + +int main(int, const char *argv[]) +{ + return MirrorMethod(flNotDir(argv[0])).Run(); +} |