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-rw-r--r--src/libutil/filesystem.cc172
-rw-r--r--src/libutil/util.cc93
-rw-r--r--src/libutil/util.hh11
3 files changed, 183 insertions, 93 deletions
diff --git a/src/libutil/filesystem.cc b/src/libutil/filesystem.cc
new file mode 100644
index 000000000..403389e60
--- /dev/null
+++ b/src/libutil/filesystem.cc
@@ -0,0 +1,172 @@
+#include <sys/time.h>
+#include <filesystem>
+
+#include "finally.hh"
+#include "util.hh"
+#include "types.hh"
+
+namespace fs = std::filesystem;
+
+namespace nix {
+
+static Path tempName(Path tmpRoot, const Path & prefix, bool includePid,
+ int & counter)
+{
+ tmpRoot = canonPath(tmpRoot.empty() ? getEnv("TMPDIR").value_or("/tmp") : tmpRoot, true);
+ if (includePid)
+ return (format("%1%/%2%-%3%-%4%") % tmpRoot % prefix % getpid() % counter++).str();
+ else
+ return (format("%1%/%2%-%3%") % tmpRoot % prefix % counter++).str();
+}
+
+Path createTempDir(const Path & tmpRoot, const Path & prefix,
+ bool includePid, bool useGlobalCounter, mode_t mode)
+{
+ static int globalCounter = 0;
+ int localCounter = 0;
+ int & counter(useGlobalCounter ? globalCounter : localCounter);
+
+ while (1) {
+ checkInterrupt();
+ Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
+ if (mkdir(tmpDir.c_str(), mode) == 0) {
+#if __FreeBSD__
+ /* Explicitly set the group of the directory. This is to
+ work around around problems caused by BSD's group
+ ownership semantics (directories inherit the group of
+ the parent). For instance, the group of /tmp on
+ FreeBSD is "wheel", so all directories created in /tmp
+ will be owned by "wheel"; but if the user is not in
+ "wheel", then "tar" will fail to unpack archives that
+ have the setgid bit set on directories. */
+ if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
+ throw SysError("setting group of directory '%1%'", tmpDir);
+#endif
+ return tmpDir;
+ }
+ if (errno != EEXIST)
+ throw SysError("creating directory '%1%'", tmpDir);
+ }
+}
+
+
+std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
+{
+ Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
+ // Strictly speaking, this is UB, but who cares...
+ // FIXME: use O_TMPFILE.
+ AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
+ if (!fd)
+ throw SysError("creating temporary file '%s'", tmpl);
+ closeOnExec(fd.get());
+ return {std::move(fd), tmpl};
+}
+
+void createSymlink(const Path & target, const Path & link,
+ std::optional<time_t> mtime)
+{
+ if (symlink(target.c_str(), link.c_str()))
+ throw SysError("creating symlink from '%1%' to '%2%'", link, target);
+ if (mtime) {
+ struct timeval times[2];
+ times[0].tv_sec = *mtime;
+ times[0].tv_usec = 0;
+ times[1].tv_sec = *mtime;
+ times[1].tv_usec = 0;
+ if (lutimes(link.c_str(), times))
+ throw SysError("setting time of symlink '%s'", link);
+ }
+}
+
+void replaceSymlink(const Path & target, const Path & link,
+ std::optional<time_t> mtime)
+{
+ for (unsigned int n = 0; true; n++) {
+ Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
+
+ try {
+ createSymlink(target, tmp, mtime);
+ } catch (SysError & e) {
+ if (e.errNo == EEXIST) continue;
+ throw;
+ }
+
+ renameFile(tmp, link);
+
+ break;
+ }
+}
+
+void setWriteTime(const fs::path & p, const struct stat & st)
+{
+ struct timeval times[2];
+ times[0] = {
+ .tv_sec = st.st_atime,
+ .tv_usec = 0,
+ };
+ times[1] = {
+ .tv_sec = st.st_mtime,
+ .tv_usec = 0,
+ };
+ if (lutimes(p.c_str(), times) != 0)
+ throw SysError("changing modification time of '%s'", p);
+}
+
+void copy(const fs::directory_entry & from, const fs::path & to, bool andDelete)
+{
+ // TODO: Rewrite the `is_*` to use `symlink_status()`
+ auto statOfFrom = lstat(from.path().c_str());
+ auto fromStatus = from.symlink_status();
+
+ // Mark the directory as writable so that we can delete its children
+ if (andDelete && fs::is_directory(fromStatus)) {
+ fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
+ }
+
+
+ if (fs::is_symlink(fromStatus) || fs::is_regular_file(fromStatus)) {
+ fs::copy(from.path(), to, fs::copy_options::copy_symlinks | fs::copy_options::overwrite_existing);
+ } else if (fs::is_directory(fromStatus)) {
+ fs::create_directory(to);
+ for (auto & entry : fs::directory_iterator(from.path())) {
+ copy(entry, to / entry.path().filename(), andDelete);
+ }
+ } else {
+ throw Error("file '%s' has an unsupported type", from.path());
+ }
+
+ setWriteTime(to, statOfFrom);
+ if (andDelete) {
+ if (!fs::is_symlink(fromStatus))
+ fs::permissions(from.path(), fs::perms::owner_write, fs::perm_options::add | fs::perm_options::nofollow);
+ fs::remove(from.path());
+ }
+}
+
+void renameFile(const Path & oldName, const Path & newName)
+{
+ fs::rename(oldName, newName);
+}
+
+void moveFile(const Path & oldName, const Path & newName)
+{
+ try {
+ renameFile(oldName, newName);
+ } catch (fs::filesystem_error & e) {
+ auto oldPath = fs::path(oldName);
+ auto newPath = fs::path(newName);
+ // For the move to be as atomic as possible, copy to a temporary
+ // directory
+ fs::path temp = createTempDir(newPath.parent_path(), "rename-tmp");
+ Finally removeTemp = [&]() { fs::remove(temp); };
+ auto tempCopyTarget = temp / "copy-target";
+ if (e.code().value() == EXDEV) {
+ fs::remove(newPath);
+ warn("Can’t rename %s as %s, copying instead", oldName, newName);
+ copy(fs::directory_entry(oldPath), tempCopyTarget, true);
+ renameFile(tempCopyTarget, newPath);
+ }
+ }
+}
+
+}
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index e11cb9c60..96ac11ea2 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -508,61 +508,6 @@ void deletePath(const Path & path, uint64_t & bytesFreed)
}
-static Path tempName(Path tmpRoot, const Path & prefix, bool includePid,
- int & counter)
-{
- tmpRoot = canonPath(tmpRoot.empty() ? getEnv("TMPDIR").value_or("/tmp") : tmpRoot, true);
- if (includePid)
- return (format("%1%/%2%-%3%-%4%") % tmpRoot % prefix % getpid() % counter++).str();
- else
- return (format("%1%/%2%-%3%") % tmpRoot % prefix % counter++).str();
-}
-
-
-Path createTempDir(const Path & tmpRoot, const Path & prefix,
- bool includePid, bool useGlobalCounter, mode_t mode)
-{
- static int globalCounter = 0;
- int localCounter = 0;
- int & counter(useGlobalCounter ? globalCounter : localCounter);
-
- while (1) {
- checkInterrupt();
- Path tmpDir = tempName(tmpRoot, prefix, includePid, counter);
- if (mkdir(tmpDir.c_str(), mode) == 0) {
-#if __FreeBSD__
- /* Explicitly set the group of the directory. This is to
- work around around problems caused by BSD's group
- ownership semantics (directories inherit the group of
- the parent). For instance, the group of /tmp on
- FreeBSD is "wheel", so all directories created in /tmp
- will be owned by "wheel"; but if the user is not in
- "wheel", then "tar" will fail to unpack archives that
- have the setgid bit set on directories. */
- if (chown(tmpDir.c_str(), (uid_t) -1, getegid()) != 0)
- throw SysError("setting group of directory '%1%'", tmpDir);
-#endif
- return tmpDir;
- }
- if (errno != EEXIST)
- throw SysError("creating directory '%1%'", tmpDir);
- }
-}
-
-
-std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
-{
- Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
- // Strictly speaking, this is UB, but who cares...
- // FIXME: use O_TMPFILE.
- AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
- if (!fd)
- throw SysError("creating temporary file '%s'", tmpl);
- closeOnExec(fd.get());
- return {std::move(fd), tmpl};
-}
-
-
std::string getUserName()
{
auto pw = getpwuid(geteuid());
@@ -684,44 +629,6 @@ Paths createDirs(const Path & path)
}
-void createSymlink(const Path & target, const Path & link,
- std::optional<time_t> mtime)
-{
- if (symlink(target.c_str(), link.c_str()))
- throw SysError("creating symlink from '%1%' to '%2%'", link, target);
- if (mtime) {
- struct timeval times[2];
- times[0].tv_sec = *mtime;
- times[0].tv_usec = 0;
- times[1].tv_sec = *mtime;
- times[1].tv_usec = 0;
- if (lutimes(link.c_str(), times))
- throw SysError("setting time of symlink '%s'", link);
- }
-}
-
-
-void replaceSymlink(const Path & target, const Path & link,
- std::optional<time_t> mtime)
-{
- for (unsigned int n = 0; true; n++) {
- Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
-
- try {
- createSymlink(target, tmp, mtime);
- } catch (SysError & e) {
- if (e.errNo == EEXIST) continue;
- throw;
- }
-
- if (rename(tmp.c_str(), link.c_str()) != 0)
- throw SysError("renaming '%1%' to '%2%'", tmp, link);
-
- break;
- }
-}
-
-
void readFull(int fd, char * buf, size_t count)
{
while (count) {
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 29227ecc6..cd83f250f 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -168,6 +168,17 @@ void createSymlink(const Path & target, const Path & link,
void replaceSymlink(const Path & target, const Path & link,
std::optional<time_t> mtime = {});
+void renameFile(const Path & src, const Path & dst);
+
+/**
+ * Similar to 'renameFile', but fallback to a copy+remove if `src` and `dst`
+ * are on a different filesystem.
+ *
+ * Beware that this might not be atomic because of the copy that happens behind
+ * the scenes
+ */
+void moveFile(const Path & src, const Path & dst);
+
/* Wrappers arount read()/write() that read/write exactly the
requested number of bytes. */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 19:20:08 +0000