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After rewriting a path, make it read-only

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This commit is contained in:
Eelco Dolstra 2020-09-23 19:10:16 +02:00
parent 31ab4c3816
commit 688bd4fb50
1 changed files with 15 additions and 32 deletions
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47
src/libstore/build.cc
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@ -3735,15 +3735,12 @@ void DerivationGoal::runChild()
}
static void moveCheckToStore(const Path & src, const Path & dst)
/* Move/rename path 'src' to 'dst'. Temporarily make 'src' writable if
it's a directory and we're not root (to be able to update the
directory's parent link ".."). */
static void movePath(const Path & src, const Path & dst)
{
/* For the rename of directory to succeed, we must be running as root or
the directory must be made temporarily writable (to update the
directory's parent link ".."). */
struct stat st;
if (lstat(src.c_str(), &st) == -1) {
throw SysError("getting attributes of path '%1%'", src);
}
auto st = lstat(src);
bool changePerm = (geteuid() && S_ISDIR(st.st_mode) && !(st.st_mode & S_IWUSR));
@ -3942,6 +3939,10 @@ void DerivationGoal::registerOutputs()
sink.s = make_ref<std::string>(rewriteStrings(*sink.s, outputRewrites));
StringSource source(*sink.s);
restorePath(actualPath, source);
/* FIXME: set proper permissions in restorePath() so
we don't have to do another traversal. */
canonicalisePathMetaData(actualPath, -1, inodesSeen);
}
};
@ -4024,7 +4025,7 @@ void DerivationGoal::registerOutputs()
[&](DerivationOutputInputAddressed output) {
/* input-addressed case */
auto requiredFinalPath = output.path;
/* Preemtively add rewrite rule for final hash, as that is
/* Preemptively add rewrite rule for final hash, as that is
what the NAR hash will use rather than normalized-self references */
if (scratchPath != requiredFinalPath)
outputRewrites.insert_or_assign(
@ -4098,27 +4099,9 @@ void DerivationGoal::registerOutputs()
else. No moving needed. */
assert(newInfo.ca);
} else {
/* Temporarily add write perm so we can move, will be fixed
later. */
{
struct stat st;
auto & mode = st.st_mode;
if (lstat(actualPath.c_str(), &st))
throw SysError("getting attributes of path '%1%'", actualPath);
mode |= 0200;
/* Try to change the perms, but only if the file isn't a
symlink as symlinks permissions are mostly ignored and
calling `chmod` on it will just forward the call to the
target of the link. */
if (!S_ISLNK(st.st_mode))
if (chmod(actualPath.c_str(), mode) == -1)
throw SysError("changing mode of '%1%' to %2$o", actualPath, mode);
}
if (rename(
actualPath.c_str(),
worker.store.toRealPath(finalDestPath).c_str()) == -1)
throw SysError("moving build output '%1%' from it's temporary location to the Nix store", finalDestPath);
actualPath = worker.store.toRealPath(finalDestPath);
auto destPath = worker.store.toRealPath(finalDestPath);
movePath(actualPath, destPath);
actualPath = destPath;
}
}
@ -4128,9 +4111,9 @@ void DerivationGoal::registerOutputs()
if (newInfo.narHash != oldInfo.narHash) {
worker.checkMismatch = true;
if (settings.runDiffHook || settings.keepFailed) {
Path dst = worker.store.toRealPath(finalDestPath + checkSuffix);
auto dst = worker.store.toRealPath(finalDestPath + checkSuffix);
deletePath(dst);
moveCheckToStore(actualPath, dst);
movePath(actualPath, dst);
handleDiffHook(
buildUser ? buildUser->getUID() : getuid(),