1 files changed, 123 insertions, 0 deletions
diff --git a/src/libstore/platform/linux.cc b/src/libstore/platform/linux.cc
new file mode 100644
index 000000000..9be3e47da
--- /dev/null
+++ b/src/libstore/platform/linux.cc
@@ -0,0 +1,123 @@
+#include "gc-store.hh"
+#include "signals.hh"
+#include "platform/linux.hh"
+
+#include <regex>
+
+namespace nix {
+static RegisterStoreImplementation<LinuxLocalStore, LocalStoreConfig> regLocalStore;
+
+static void readProcLink(const std::string & file, UncheckedRoots & roots)
+{
+    constexpr auto bufsiz = PATH_MAX;
+    char buf[bufsiz];
+    auto res = readlink(file.c_str(), buf, bufsiz);
+    if (res == -1) {
+        if (errno == ENOENT || errno == EACCES || errno == ESRCH) {
+            return;
+        }
+        throw SysError("reading symlink");
+    }
+    if (res == bufsiz) {
+        throw Error("overly long symlink starting with '%1%'", std::string_view(buf, bufsiz));
+    }
+    if (res > 0 && buf[0] == '/') {
+        roots[std::string(static_cast<char *>(buf), res)].emplace(file);
+    }
+}
+
+static std::string quoteRegexChars(const std::string & raw)
+{
+    static auto specialRegex = std::regex(R"([.^$\\*+?()\[\]{}|])");
+    return std::regex_replace(raw, specialRegex, R"(\$&)");
+}
+
+static void readFileRoots(const char * path, UncheckedRoots & roots)
+{
+    try {
+        roots[readFile(path)].emplace(path);
+    } catch (SysError & e) {
+        if (e.errNo != ENOENT && e.errNo != EACCES) {
+            throw;
+        }
+    }
+}
+
+void LinuxLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
+{
+    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.get())) {
+            checkInterrupt();
+            if (std::regex_match(ent->d_name, digitsRegex)) {
+                try {
+                    readProcLink(fmt("/proc/%s/exe", ent->d_name), unchecked);
+                    readProcLink(fmt("/proc/%s/cwd", ent->d_name), unchecked);
+
+                    auto fdStr = fmt("/proc/%s/fd", ent->d_name);
+                    auto fdDir = AutoCloseDir(opendir(fdStr.c_str()));
+                    if (!fdDir) {
+                        if (errno == ENOENT || errno == EACCES) {
+                            continue;
+                        }
+                        throw SysError("opening %1%", fdStr);
+                    }
+                    struct dirent * fd_ent;
+                    while (errno = 0, fd_ent = readdir(fdDir.get())) {
+                        if (fd_ent->d_name[0] != '.') {
+                            readProcLink(fmt("%s/%s", fdStr, fd_ent->d_name), unchecked);
+                        }
+                    }
+                    if (errno) {
+                        if (errno == ESRCH) {
+                            continue;
+                        }
+                        throw SysError("iterating /proc/%1%/fd", ent->d_name);
+                    }
+                    fdDir.reset();
+
+                    auto mapFile = fmt("/proc/%s/maps", ent->d_name);
+                    auto mapLines =
+                        tokenizeString<std::vector<std::string>>(readFile(mapFile), "\n");
+                    for (const auto & line : mapLines) {
+                        auto match = std::smatch{};
+                        if (std::regex_match(line, match, mapRegex)) {
+                            unchecked[match[1]].emplace(mapFile);
+                        }
+                    }
+
+                    auto envFile = fmt("/proc/%s/environ", ent->d_name);
+                    auto envString = readFile(envFile);
+                    auto env_end = std::sregex_iterator{};
+                    for (auto i =
+                             std::sregex_iterator{
+                                 envString.begin(), envString.end(), storePathRegex
+                             };
+                         i != env_end;
+                         ++i)
+                    {
+                        unchecked[i->str()].emplace(envFile);
+                    }
+                } catch (SysError & e) {
+                    if (errno == ENOENT || errno == EACCES || errno == ESRCH) {
+                        continue;
+                    }
+                    throw;
+                }
+            }
+        }
+        if (errno) {
+            throw SysError("iterating /proc");
+        }
+    }
+
+    readFileRoots("/proc/sys/kernel/modprobe", unchecked);
+    readFileRoots("/proc/sys/kernel/fbsplash", unchecked);
+    readFileRoots("/proc/sys/kernel/poweroff_cmd", unchecked);
+}
+}