Files
FastSync/src/shared/file.h
T
TapTap 67076bf218 feat(basis): rsync quick-check default + FastSync-only --verify-basis
- default basis match is rsync's metadata quick-check (size + mtime; size-only
  drops mtime; -I disables), no mandatory content digest
- new long-only --verify-basis (wire bool, protocol stays 2.28.0) restores the
  strict whole-file content equality
- --copy-dest re-applies source attributes; basis-hit 256 MiB cap removed by
  streaming the copy/hash; basis miss keeps the normal payload bound
- compare/copy/link-dest rows -> caveat; tally 116/13/28
2026-09-19 15:55:51 +02:00

200 lines
13 KiB
C

#ifndef FILE_H
#define FILE_H
#include "file_send.h"
#include "file_receive.h"
#include "file_types.h"
#include "checksum.h"
#include <stdbool.h>
#include <stdint.h>
#include <sys/stat.h>
/* File/FileMetadata lifecycle, local disk helpers, and secure filesystem
primitives shared by the send/receive pipelines. */
File* file_create(const char* path);
void file_destroy(void* item);
bool file_load_data(File* file);
/* Compute the whole-file content digest of `file` with the negotiated
* --checksum-choice algorithm and --checksum-seed. Writes the digest into
* `out` (capacity `out_capacity`) and its length into `*out_len`. Returns
* false on read/allocation failure or when the digest would not fit. */
bool file_checksum(File* file, ChecksumAlgo algo, uint64_t seed, uint8_t* out, size_t out_capacity,
size_t* out_len);
size_t file_content_to_buffer(File* file);
FileMetadata* file_metadata_create(const char* path, const struct stat* stats, bool capture_atime,
bool capture_crtime);
void file_metadata_destroy(void* metadata);
/* --open-noatime process-wide sender policy; see file.c. */
void file_set_open_noatime(bool enable);
bool file_get_open_noatime(void);
/* Capture the process umask ONCE, before any threads are created. Call this at
* the very top of main() in both entry points so the cached value is read while
* the process is still single-threaded: reading the umask needs a get+set round
* trip (umask(0); umask(old)), which would race against receiver threads
* creating files if it happened during the first write. Idempotent and safe to
* call more than once. */
void file_umask_capture(void);
/* Process-wide umask, captured once (thread-safe). Used to derive the mode of
* a brand-new destination like rsync: source_mode & 0777 & ~umask. Falls back
* to file_umask_capture() (behind pthread_once) if capture was never called. */
unsigned file_process_umask(void);
/* Open `path` read-only for transfer, honouring --open-noatime when set. */
int file_open_for_read(const char* path);
bool file_write_to_disk(const char* path, const void* data, unsigned long long data_size,
bool inplace, bool sparse);
/* Symlink trust-boundary helpers (Phase 4, symlink wave; rsync parity).
* --munge-links is a RECEIVER-side rewrite: rsync prefixes every stored symlink
* target with this marker, making the link unusable while the referenced
* directory does not exist. A SENDER receiving a munged source strips it back
* off before transmitting (so a munged tree round-trips through the receiver's
* re-munging). */
#define SYMLINK_MUNGE_PREFIX "/rsyncd-munged/"
char* file_symlink_munge(const char* target);
/* rsync 3.4.1 unsafe_symlink(): true when `target` escapes the transfer tree
* rooted at `link_path` (the symlink's transfer-relative path incl. its name).
* Absolute/empty targets and targets climbing above the transfer root (via
* "..") are unsafe, as are internal "/../" components and trailing "/..". */
bool file_symlink_unsafe(const char* target, const char* link_path);
/* True when a lexical target is relative and contains no ".." component, so it
* can never escape the receive root once created beneath it. */
bool file_symlink_target_contained(const char* target);
/* Strip a leading SYMLINK_MUNGE_PREFIX from `target` (mutable, in place);
* returns true when a marker was removed. */
bool file_symlink_unmunge(char* target);
/* Create a symlink at `path` -> `target`, confined below the authorized root
* (O_NOFOLLOW parent walk, symlinkat; the target is never followed). The link
* value is copied verbatim (rsync -l); only the placement path is confined.
* Returns false when a directory already occupies `path`. */
bool file_symlink_at_secure(const char* path, const char* target);
/* --keep-dirlinks (-K) receiver process-wide policy: allow an in-root existing
* symlink-to-directory to be followed as a directory. */
void file_set_keep_dirlinks(bool enable);
/* --trust-sender receiver process-wide policy (Phase 5). When set, the
* receiver trusts that the sender already produced a clean file list and skips
* its own redundant up-front re-validation of incoming paths (the empty/".."
* rejection and the escaping-symlink-target containment). The low-level
* fd-relative confinement primitives below are deliberately NOT disabled by
* this flag, so a hostile sender still cannot escape the authorized root. */
void file_set_trust_sender(bool enable);
bool file_get_trust_sender(void);
/* Secure path/filesystem primitives (symlink-safe, O_NOFOLLOW, root-confined). */
bool file_path_exists_secure(const char* path);
bool file_stat_secure(const char* path, struct stat* st);
bool file_destination_is_newer_secure(const char* path, const FileMetadata* metadata);
int file_open_secure_parent(const char* path, char** leaf_out, bool create_dirs);
/* Protocol 2.28.0 variant: also increments *dirs_created for every missing
* parent directory this walk creates that lies strictly below `count_floor`
* (a receive-root-relative path, or NULL to count all of them). */
int file_open_secure_parent_counted(const char* path, char** leaf_out, bool create_dirs,
unsigned* dirs_created, const char* count_floor);
bool file_ensure_directory_secure(const char* path);
bool file_directory_exists_secure(const char* path);
bool file_rename_secure(const char* old_path, const char* new_path);
/* Remove the whole directory tree at `path` (confined, symlink-safe). Used by
--force to clear a non-empty destination directory that blocks an incoming
regular file. See the .c for the exact success semantics. */
bool file_remove_tree_secure(const char* path);
/* Open a private 0700 directory (creating it on demand) that must live below
the authorized root. Used for the --delay-updates staging directory. */
int file_open_private_dir(const char* dir_path);
/* Open an existing --temp-dir scratch directory as-is (absolute or relative;
no creation, no root confinement), matching rsync's --temp-dir handling. */
int file_open_temp_dir(const char* dir_path);
/* The file_to_disk_secure* variants write a temporary copy in the destination
directory and atomically rename it over `path`. temp_dir is a scratch
directory (an absolute path, or one the caller already resolved against the
destination root): when it is non-NULL the temporary copy is instead created
there (with a name unique across the whole scratch directory) and atomically
renamed into the destination directory once fully written and fsynced. When
that rename/link fails with EXDEV (the scratch dir is on another filesystem)
the write falls back to a non-atomic copy directly in the destination
directory, matching rsync. Pass NULL for the same-directory behavior.
--inplace writes never use temp_dir. */
bool file_to_disk_secure(const char* path, const void* data, unsigned long long data_size,
bool inplace, bool sparse, bool preallocate, const FileMetadata* metadata,
FileAttrPolicy policy, const char* temp_dir);
bool file_to_disk_secure_with_fsync(const char* path, const void* data,
unsigned long long data_size, bool inplace, bool sparse,
bool preallocate, const FileMetadata* metadata,
FileAttrPolicy policy, bool use_fsync, const char* temp_dir);
/* With update enabled, an existing newer destination is left untouched. The
check is descriptor-based for inplace writes; atomic replacement still has
an unavoidable final rename race without filesystem locking. */
bool file_to_disk_secure_update(const char* path, const void* data, unsigned long long data_size,
bool inplace, bool sparse, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy,
const char* temp_dir);
bool file_to_disk_secure_no_replace(const char* path, const void* data,
unsigned long long data_size, bool sparse, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy,
const char* temp_dir);
/* Receiver write-path variant that also applies per-file xattrs (-X/-A) and the
* --fake-super stat xattr fd-relative before the final rename. `update` /
* `no_replace` / `use_fsync` mirror the plain wrappers above; `keep_partial`
* enables --partial best-effort retention of a failed write's temp. */
bool file_to_disk_secure_attrs(const char* path, const void* data, unsigned long long data_size,
bool inplace, bool sparse, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy, bool update,
bool no_replace, bool use_fsync, const FileXattrList* xattrs,
bool fake_super, bool keep_partial, const char* temp_dir);
/* Atomic --link-dest install: replace `path` with a hard link to `basis_path`
(via a temp name + rename); fall back to a byte-identical local copy from
`data` when the link is impossible (EXDEV/EPERM/unsupported filesystem).
`metadata` is applied only on the copy fallback. `preallocate` applies to
that copy fallback only (a hard-linked file shares the basis inode and is
never re-allocated). */
bool file_to_disk_secure_link(const char* path, const char* basis_path, const void* data,
unsigned long long data_size, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy, bool use_fsync,
const char* temp_dir);
/* Like file_to_disk_secure_link, but the byte-copy fallback also applies the
* per-file xattrs (-X/-A) and --fake-super stat xattr (fd-relative). On a
* successful hard link no attributes are applied (the shared inode already
* carries the basis's). */
bool file_to_disk_secure_link_attrs(const char* path, const char* basis_path, const void* data,
unsigned long long data_size, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy,
bool use_fsync, const FileXattrList* xattrs, bool fake_super,
const char* temp_dir);
/* Streaming --copy-dest install: atomically materialize `path` by copying the
* bytes of `basis_path` through a bounded buffer (no whole-file buffering, so
* an arbitrarily large basis works), applying the SOURCE metadata and the
* per-file xattrs / --fake-super record. `update` honors a newer destination;
* a --temp-dir scratch location falls back to a direct write on EXDEV. */
bool file_copy_basis_stream_attrs(const char* path, const char* basis_path,
unsigned long long expected_size, bool preallocate,
const FileMetadata* metadata, FileAttrPolicy policy, bool update,
bool use_fsync, const FileXattrList* xattrs, bool fake_super,
const char* temp_dir);
/* Protocol 2.28.0 receiver-stat variants: like the two above but additionally
* report through `dirs_created` (when non-NULL) how many parent directories the
* confined secure walk had to create that lie strictly below `count_floor` (a
* receive-root-relative prefix, or NULL for all). Used to reproduce rsync's
* `Number of created files` directory count on a fresh destination. */
bool file_to_disk_secure_attrs_counted(const char* path, const void* data,
unsigned long long data_size, bool inplace, bool sparse,
bool preallocate, const FileMetadata* metadata,
FileAttrPolicy policy, bool update, bool no_replace,
bool use_fsync, const FileXattrList* xattrs, bool fake_super,
bool keep_partial, const char* temp_dir,
unsigned* dirs_created, const char* count_floor);
bool file_to_disk_secure_link_attrs_counted(const char* path, const char* basis_path,
const void* data, unsigned long long data_size,
bool preallocate, const FileMetadata* metadata,
FileAttrPolicy policy, bool use_fsync,
const FileXattrList* xattrs, bool fake_super,
const char* temp_dir, unsigned* dirs_created,
const char* count_floor);
/* The logical transfer root expressed receive-root-relative, or NULL when the
* wire paths carry no mirror scaffolding above it. Caller frees non-NULL. */
char* file_transfer_root_floor(const Config* config);
#endif