mirror of
https://github.com/privatevoid-net/nix-super.git
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Put canonicaliseTimestampAndPermissions in its own header/file
It is not inherently tied to `LocalStore`, it could probably even go in `libnixutil`. Functions not attached to `LocalStore` should not be declared in `local-store.hh`. I am moving it to facilitate experimenting for #9344. If canonicalisation should be done client-side in client-side builds, there wouldn't be a `LocalStore` at all so having to include that header to get this freestanding function is cumbersome and wrong. Perhaps canonicalisation should still be done server-side for security reasons --- I don't mean to make that judgement call now --- but even if so, this freestanding function still isn't connected to `LocalStore` so while less urgent it is still better to move out of this header.
This commit is contained in:
John Ericson
parent
9cd69e1c39
commit
f880469173
7 changed files with 218 additions and 192 deletions
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@ -19,6 +19,7 @@
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#include "namespaces.hh"
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#include "child.hh"
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#include "unix-domain-socket.hh"
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#include "posix-fs-canonicalise.hh"
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#include <regex>
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#include <queue>
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@ -11,6 +11,7 @@
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#include "finally.hh"
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#include "compression.hh"
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#include "signals.hh"
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#include "posix-fs-canonicalise.hh"
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#include <iostream>
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#include <algorithm>
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@ -581,164 +582,6 @@ void LocalStore::makeStoreWritable()
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}
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const time_t mtimeStore = 1; /* 1 second into the epoch */
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static void canonicaliseTimestampAndPermissions(const Path & path, const struct stat & st)
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{
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if (!S_ISLNK(st.st_mode)) {
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/* Mask out all type related bits. */
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mode_t mode = st.st_mode & ~S_IFMT;
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if (mode != 0444 && mode != 0555) {
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mode = (st.st_mode & S_IFMT)
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| 0444
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| (st.st_mode & S_IXUSR ? 0111 : 0);
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if (chmod(path.c_str(), mode) == -1)
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throw SysError("changing mode of '%1%' to %2$o", path, mode);
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}
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}
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if (st.st_mtime != mtimeStore) {
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struct timeval times[2];
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times[0].tv_sec = st.st_atime;
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times[0].tv_usec = 0;
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times[1].tv_sec = mtimeStore;
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times[1].tv_usec = 0;
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#if HAVE_LUTIMES
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if (lutimes(path.c_str(), times) == -1)
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if (errno != ENOSYS ||
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(!S_ISLNK(st.st_mode) && utimes(path.c_str(), times) == -1))
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#else
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if (!S_ISLNK(st.st_mode) && utimes(path.c_str(), times) == -1)
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#endif
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throw SysError("changing modification time of '%1%'", path);
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}
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}
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void canonicaliseTimestampAndPermissions(const Path & path)
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{
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canonicaliseTimestampAndPermissions(path, lstat(path));
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}
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static void canonicalisePathMetaData_(
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const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange,
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InodesSeen & inodesSeen)
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{
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checkInterrupt();
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#if __APPLE__
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/* Remove flags, in particular UF_IMMUTABLE which would prevent
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the file from being garbage-collected. FIXME: Use
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setattrlist() to remove other attributes as well. */
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if (lchflags(path.c_str(), 0)) {
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if (errno != ENOTSUP)
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throw SysError("clearing flags of path '%1%'", path);
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}
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#endif
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auto st = lstat(path);
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/* Really make sure that the path is of a supported type. */
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if (!(S_ISREG(st.st_mode) || S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode)))
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throw Error("file '%1%' has an unsupported type", path);
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#if __linux__
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/* Remove extended attributes / ACLs. */
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ssize_t eaSize = llistxattr(path.c_str(), nullptr, 0);
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if (eaSize < 0) {
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if (errno != ENOTSUP && errno != ENODATA)
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throw SysError("querying extended attributes of '%s'", path);
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} else if (eaSize > 0) {
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std::vector<char> eaBuf(eaSize);
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if ((eaSize = llistxattr(path.c_str(), eaBuf.data(), eaBuf.size())) < 0)
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throw SysError("querying extended attributes of '%s'", path);
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for (auto & eaName: tokenizeString<Strings>(std::string(eaBuf.data(), eaSize), std::string("\000", 1))) {
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if (settings.ignoredAcls.get().count(eaName)) continue;
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if (lremovexattr(path.c_str(), eaName.c_str()) == -1)
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throw SysError("removing extended attribute '%s' from '%s'", eaName, path);
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}
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}
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#endif
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/* Fail if the file is not owned by the build user. This prevents
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us from messing up the ownership/permissions of files
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hard-linked into the output (e.g. "ln /etc/shadow $out/foo").
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However, ignore files that we chown'ed ourselves previously to
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ensure that we don't fail on hard links within the same build
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(i.e. "touch $out/foo; ln $out/foo $out/bar"). */
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if (uidRange && (st.st_uid < uidRange->first || st.st_uid > uidRange->second)) {
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if (S_ISDIR(st.st_mode) || !inodesSeen.count(Inode(st.st_dev, st.st_ino)))
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throw BuildError("invalid ownership on file '%1%'", path);
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mode_t mode = st.st_mode & ~S_IFMT;
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assert(S_ISLNK(st.st_mode) || (st.st_uid == geteuid() && (mode == 0444 || mode == 0555) && st.st_mtime == mtimeStore));
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return;
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}
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inodesSeen.insert(Inode(st.st_dev, st.st_ino));
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canonicaliseTimestampAndPermissions(path, st);
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/* Change ownership to the current uid. If it's a symlink, use
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lchown if available, otherwise don't bother. Wrong ownership
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of a symlink doesn't matter, since the owning user can't change
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the symlink and can't delete it because the directory is not
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writable. The only exception is top-level paths in the Nix
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store (since that directory is group-writable for the Nix build
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users group); we check for this case below. */
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if (st.st_uid != geteuid()) {
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#if HAVE_LCHOWN
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if (lchown(path.c_str(), geteuid(), getegid()) == -1)
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#else
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if (!S_ISLNK(st.st_mode) &&
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chown(path.c_str(), geteuid(), getegid()) == -1)
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#endif
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throw SysError("changing owner of '%1%' to %2%",
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path, geteuid());
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}
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if (S_ISDIR(st.st_mode)) {
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DirEntries entries = readDirectory(path);
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for (auto & i : entries)
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canonicalisePathMetaData_(path + "/" + i.name, uidRange, inodesSeen);
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}
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}
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void canonicalisePathMetaData(
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const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange,
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InodesSeen & inodesSeen)
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{
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canonicalisePathMetaData_(path, uidRange, inodesSeen);
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/* On platforms that don't have lchown(), the top-level path can't
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be a symlink, since we can't change its ownership. */
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auto st = lstat(path);
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if (st.st_uid != geteuid()) {
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assert(S_ISLNK(st.st_mode));
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throw Error("wrong ownership of top-level store path '%1%'", path);
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}
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}
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void canonicalisePathMetaData(const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange)
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{
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InodesSeen inodesSeen;
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canonicalisePathMetaData(path, uidRange, inodesSeen);
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}
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void LocalStore::registerDrvOutput(const Realisation & info, CheckSigsFlag checkSigs)
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{
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experimentalFeatureSettings.require(Xp::CaDerivations);
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@ -371,38 +371,4 @@ private:
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friend struct DerivationGoal;
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};
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typedef std::pair<dev_t, ino_t> Inode;
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typedef std::set<Inode> InodesSeen;
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/**
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* "Fix", or canonicalise, the meta-data of the files in a store path
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* after it has been built. In particular:
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*
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* - the last modification date on each file is set to 1 (i.e.,
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* 00:00:01 1/1/1970 UTC)
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*
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* - the permissions are set of 444 or 555 (i.e., read-only with or
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* without execute permission; setuid bits etc. are cleared)
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*
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* - the owner and group are set to the Nix user and group, if we're
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* running as root.
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*
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* If uidRange is not empty, this function will throw an error if it
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* encounters files owned by a user outside of the closed interval
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* [uidRange->first, uidRange->second].
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*/
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void canonicalisePathMetaData(
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const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange,
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InodesSeen & inodesSeen);
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void canonicalisePathMetaData(
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const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange);
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void canonicaliseTimestampAndPermissions(const Path & path);
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MakeError(PathInUse, Error);
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}
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@ -1,6 +1,7 @@
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#include "local-store.hh"
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#include "globals.hh"
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#include "signals.hh"
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#include "posix-fs-canonicalise.hh"
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#include <cstdlib>
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#include <cstring>
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169
src/libstore/posix-fs-canonicalise.cc
Normal file
169
src/libstore/posix-fs-canonicalise.cc
Normal file
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@ -0,0 +1,169 @@
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#include <sys/xattr.h>
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#include "posix-fs-canonicalise.hh"
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#include "file-system.hh"
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#include "signals.hh"
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#include "util.hh"
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#include "globals.hh"
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#include "store-api.hh"
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namespace nix {
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const time_t mtimeStore = 1; /* 1 second into the epoch */
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static void canonicaliseTimestampAndPermissions(const Path & path, const struct stat & st)
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{
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if (!S_ISLNK(st.st_mode)) {
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/* Mask out all type related bits. */
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mode_t mode = st.st_mode & ~S_IFMT;
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if (mode != 0444 && mode != 0555) {
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mode = (st.st_mode & S_IFMT)
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| 0444
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| (st.st_mode & S_IXUSR ? 0111 : 0);
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if (chmod(path.c_str(), mode) == -1)
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throw SysError("changing mode of '%1%' to %2$o", path, mode);
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}
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}
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if (st.st_mtime != mtimeStore) {
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struct timeval times[2];
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times[0].tv_sec = st.st_atime;
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times[0].tv_usec = 0;
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times[1].tv_sec = mtimeStore;
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times[1].tv_usec = 0;
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#if HAVE_LUTIMES
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if (lutimes(path.c_str(), times) == -1)
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if (errno != ENOSYS ||
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(!S_ISLNK(st.st_mode) && utimes(path.c_str(), times) == -1))
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#else
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if (!S_ISLNK(st.st_mode) && utimes(path.c_str(), times) == -1)
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#endif
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throw SysError("changing modification time of '%1%'", path);
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}
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}
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void canonicaliseTimestampAndPermissions(const Path & path)
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{
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canonicaliseTimestampAndPermissions(path, lstat(path));
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}
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static void canonicalisePathMetaData_(
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const Path & path,
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std::optional<std::pair<uid_t, uid_t>> uidRange,
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InodesSeen & inodesSeen)
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{
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checkInterrupt();
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#if __APPLE__
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/* Remove flags, in particular UF_IMMUTABLE which would prevent
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the file from being garbage-collected. FIXME: Use
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setattrlist() to remove other attributes as well. */
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if (lchflags(path.c_str(), 0)) {
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if (errno != ENOTSUP)
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throw SysError("clearing flags of path '%1%'", path);
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}
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#endif
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auto st = lstat(path);
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/* Really make sure that the path is of a supported type. */
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if (!(S_ISREG(st.st_mode) || S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode)))
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throw Error("file '%1%' has an unsupported type", path);
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#if __linux__
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/* Remove extended attributes / ACLs. */
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ssize_t eaSize = llistxattr(path.c_str(), nullptr, 0);
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if (eaSize < 0) {
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if (errno != ENOTSUP && errno != ENODATA)
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throw SysError("querying extended attributes of '%s'", path);
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} else if (eaSize > 0) {
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std::vector<char> eaBuf(eaSize);
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if ((eaSize = llistxattr(path.c_str(), eaBuf.data(), eaBuf.size())) < 0)
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throw SysError("querying extended attributes of '%s'", path);
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for (auto & eaName: tokenizeString<Strings>(std::string(eaBuf.data(), eaSize), std::string("\000", 1))) {
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if (settings.ignoredAcls.get().count(eaName)) continue;
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if (lremovexattr(path.c_str(), eaName.c_str()) == -1)
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throw SysError("removing extended attribute '%s' from '%s'", eaName, path);
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}
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}
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#endif
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/* Fail if the file is not owned by the build user. This prevents
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us from messing up the ownership/permissions of files
|
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hard-linked into the output (e.g. "ln /etc/shadow $out/foo").
|
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However, ignore files that we chown'ed ourselves previously to
|
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ensure that we don't fail on hard links within the same build
|
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(i.e. "touch $out/foo; ln $out/foo $out/bar"). */
|
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if (uidRange && (st.st_uid < uidRange->first || st.st_uid > uidRange->second)) {
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if (S_ISDIR(st.st_mode) || !inodesSeen.count(Inode(st.st_dev, st.st_ino)))
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throw BuildError("invalid ownership on file '%1%'", path);
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mode_t mode = st.st_mode & ~S_IFMT;
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assert(S_ISLNK(st.st_mode) || (st.st_uid == geteuid() && (mode == 0444 || mode == 0555) && st.st_mtime == mtimeStore));
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return;
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}
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inodesSeen.insert(Inode(st.st_dev, st.st_ino));
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canonicaliseTimestampAndPermissions(path, st);
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|
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/* Change ownership to the current uid. If it's a symlink, use
|
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lchown if available, otherwise don't bother. Wrong ownership
|
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of a symlink doesn't matter, since the owning user can't change
|
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the symlink and can't delete it because the directory is not
|
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writable. The only exception is top-level paths in the Nix
|
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store (since that directory is group-writable for the Nix build
|
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users group); we check for this case below. */
|
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if (st.st_uid != geteuid()) {
|
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#if HAVE_LCHOWN
|
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if (lchown(path.c_str(), geteuid(), getegid()) == -1)
|
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#else
|
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if (!S_ISLNK(st.st_mode) &&
|
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chown(path.c_str(), geteuid(), getegid()) == -1)
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#endif
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throw SysError("changing owner of '%1%' to %2%",
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path, geteuid());
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}
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|
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if (S_ISDIR(st.st_mode)) {
|
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DirEntries entries = readDirectory(path);
|
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for (auto & i : entries)
|
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canonicalisePathMetaData_(path + "/" + i.name, uidRange, inodesSeen);
|
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}
|
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}
|
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|
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|
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void canonicalisePathMetaData(
|
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const Path & path,
|
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std::optional<std::pair<uid_t, uid_t>> uidRange,
|
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InodesSeen & inodesSeen)
|
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{
|
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canonicalisePathMetaData_(path, uidRange, inodesSeen);
|
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|
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/* On platforms that don't have lchown(), the top-level path can't
|
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be a symlink, since we can't change its ownership. */
|
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auto st = lstat(path);
|
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|
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if (st.st_uid != geteuid()) {
|
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assert(S_ISLNK(st.st_mode));
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throw Error("wrong ownership of top-level store path '%1%'", path);
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}
|
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}
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|
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|
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void canonicalisePathMetaData(const Path & path,
|
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std::optional<std::pair<uid_t, uid_t>> uidRange)
|
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{
|
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InodesSeen inodesSeen;
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canonicalisePathMetaData(path, uidRange, inodesSeen);
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}
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}
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45
src/libstore/posix-fs-canonicalise.hh
Normal file
45
src/libstore/posix-fs-canonicalise.hh
Normal file
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@ -0,0 +1,45 @@
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#pragma once
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///@file
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#include <sys/stat.h>
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#include <sys/time.h>
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|
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#include "types.hh"
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#include "error.hh"
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|
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namespace nix {
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|
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typedef std::pair<dev_t, ino_t> Inode;
|
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typedef std::set<Inode> InodesSeen;
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|
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|
||||
/**
|
||||
* "Fix", or canonicalise, the meta-data of the files in a store path
|
||||
* after it has been built. In particular:
|
||||
*
|
||||
* - the last modification date on each file is set to 1 (i.e.,
|
||||
* 00:00:01 1/1/1970 UTC)
|
||||
*
|
||||
* - the permissions are set of 444 or 555 (i.e., read-only with or
|
||||
* without execute permission; setuid bits etc. are cleared)
|
||||
*
|
||||
* - the owner and group are set to the Nix user and group, if we're
|
||||
* running as root.
|
||||
*
|
||||
* If uidRange is not empty, this function will throw an error if it
|
||||
* encounters files owned by a user outside of the closed interval
|
||||
* [uidRange->first, uidRange->second].
|
||||
*/
|
||||
void canonicalisePathMetaData(
|
||||
const Path & path,
|
||||
std::optional<std::pair<uid_t, uid_t>> uidRange,
|
||||
InodesSeen & inodesSeen);
|
||||
void canonicalisePathMetaData(
|
||||
const Path & path,
|
||||
std::optional<std::pair<uid_t, uid_t>> uidRange);
|
||||
|
||||
void canonicaliseTimestampAndPermissions(const Path & path);
|
||||
|
||||
MakeError(PathInUse, Error);
|
||||
|
||||
}
|
||||
|
|
@ -14,6 +14,7 @@
|
|||
#include "graphml.hh"
|
||||
#include "legacy.hh"
|
||||
#include "path-with-outputs.hh"
|
||||
#include "posix-fs-canonicalise.hh"
|
||||
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
|
|
|
|||
Loading…
Reference in a new issue