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/*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*-
*
* librsync -- library for network deltas
*
* Copyright 2000, 2001, 2014, 2015 by Martin Pool <mbp@sourcefrog.net>
* Copyright (C) 2003 by Donovan Baarda <abo@minkirri.apana.org.au>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*=
| You should never wear your best
| trousers when you go out to fight for
| freedom and liberty.
| -- Henrik Ibsen
*/
/** \file librsync.h
* Public header for librsync. */
#ifndef _RSYNC_H
# define _RSYNC_H
# include <stdio.h>
# include <stdint.h>
# include <time.h>
# include "librsync_export.h"
# ifdef __cplusplus
extern "C" {
# endif
/** Library version string.
*
* \sa \ref versioning */
LIBRSYNC_EXPORT extern char const rs_librsync_version[];
typedef uint8_t rs_byte_t;
typedef intmax_t rs_long_t;
/*=
| "The IETF already has more than enough
| RFCs that codify the obvious, make
| stupidity illegal, support truth,
| justice, and the IETF way, and generally
| demonstrate the author is a brilliant and
| valuable Contributor to The Standards
| Process."
| -- Vernon Schryver
*/
/** A uint32 magic number, emitted in bigendian/network order at the start of
* librsync files. */
typedef enum {
/** A delta file.
*
* At present, there's only one delta format.
*
* The four-byte literal \c "rs\x026". */
RS_DELTA_MAGIC = 0x72730236,
/** A signature file with MD4 signatures.
*
* Backward compatible with librsync < 1.0, but strongly deprecated because
* it creates a security vulnerability on files containing partly untrusted
* data. See <https://github.com/librsync/librsync/issues/5>.
*
* The four-byte literal \c "rs\x016".
*
* \sa rs_sig_begin() */
RS_MD4_SIG_MAGIC = 0x72730136,
/** A signature file using the BLAKE2 hash. Supported from librsync 1.0.
*
* The four-byte literal \c "rs\x017".
*
* \sa rs_sig_begin() */
RS_BLAKE2_SIG_MAGIC = 0x72730137,
/** A signature file with RabinKarp rollsum and MD4 hash.
*
* Uses a faster/safer rollsum, but still strongly discouraged because of
* MD4's security vulnerability. Supported since librsync 2.2.0.
*
* The four-byte literal \c "rs\x01F".
*
* \sa rs_sig_begin() */
RS_RK_MD4_SIG_MAGIC = 0x72730146,
/** A signature file with RabinKarp rollsum and BLAKE2 hash.
*
* Uses a faster/safer rollsum together with the safer BLAKE2 hash. This is
* the recommended default supported since librsync 2.2.0.
*
* The four-byte literal \c "rs\x01G".
*
* \sa rs_sig_begin() */
RS_RK_BLAKE2_SIG_MAGIC = 0x72730147,
} rs_magic_number;
/** Log severity levels.
*
* These are the same as syslog, at least in glibc.
*
* \sa rs_trace_set_level() \sa \ref api_trace */
typedef enum {
RS_LOG_EMERG = 0, /**< System is unusable */
RS_LOG_ALERT = 1, /**< Action must be taken immediately */
RS_LOG_CRIT = 2, /**< Critical conditions */
RS_LOG_ERR = 3, /**< Error conditions */
RS_LOG_WARNING = 4, /**< Warning conditions */
RS_LOG_NOTICE = 5, /**< Normal but significant condition */
RS_LOG_INFO = 6, /**< Informational */
RS_LOG_DEBUG = 7 /**< Debug-level messages */
} rs_loglevel;
/** Callback to write out log messages.
*
* \param level a syslog level.
*
* \param msg message to be logged.
*
* \sa \ref api_trace */
typedef void rs_trace_fn_t(rs_loglevel level, char const *msg);
/** Set the least important message severity that will be output.
*
* \sa \ref api_trace */
LIBRSYNC_EXPORT void rs_trace_set_level(rs_loglevel level);
/** Set trace callback.
*
* \sa \ref api_trace */
LIBRSYNC_EXPORT void rs_trace_to(rs_trace_fn_t *);
/** Default trace callback that writes to stderr.
*
* Implements ::rs_trace_fn_t, and may be passed to rs_trace_to().
*
* \sa \ref api_trace */
LIBRSYNC_EXPORT void rs_trace_stderr(rs_loglevel level, char const *msg);
/** Check whether the library was compiled with debugging trace.
*
* \returns True if the library contains trace code; otherwise false.
*
* If this returns false, then trying to turn trace on will achieve nothing.
*
* \sa \ref api_trace */
LIBRSYNC_EXPORT int rs_supports_trace(void);
/** Convert \p from_len bytes at \p from_buf into a hex representation in \p
* to_buf, which must be twice as long plus one byte for the null terminator. */
LIBRSYNC_EXPORT void rs_hexify(char *to_buf, void const *from_buf,
int from_len);
/** Decode a base64 buffer in place.
*
* \returns The number of binary bytes. */
LIBRSYNC_EXPORT size_t rs_unbase64(char *s);
/** Encode a buffer as base64. */
LIBRSYNC_EXPORT void rs_base64(unsigned char const *buf, int n, char *out);
/** Return codes from nonblocking rsync operations.
*
* \sa rs_strerror() \sa api_callbacks */
typedef enum rs_result {
RS_DONE = 0, /**< Completed successfully. */
RS_BLOCKED = 1, /**< Blocked waiting for more data. */
RS_RUNNING = 2, /**< The job is still running, and not yet
* finished or blocked. (This value should
* never be seen by the application.) */
RS_TEST_SKIPPED = 77, /**< Test neither passed or failed. */
RS_IO_ERROR = 100, /**< Error in file or network IO. */
RS_SYNTAX_ERROR = 101, /**< Command line syntax error. */
RS_MEM_ERROR = 102, /**< Out of memory. */
RS_INPUT_ENDED = 103, /**< Unexpected end of input file, perhaps due
* to a truncated file or dropped network
* connection. */
RS_BAD_MAGIC = 104, /**< Bad magic number at start of stream.
* Probably not a librsync file, or possibly
* the wrong kind of file or from an
* incompatible library version. */
RS_UNIMPLEMENTED = 105, /**< Author is lazy. */
RS_CORRUPT = 106, /**< Unbelievable value in stream. */
RS_INTERNAL_ERROR = 107, /**< Probably a library bug. */
RS_PARAM_ERROR = 108 /**< Bad value passed in to library, probably
* an application bug. */
} rs_result;
/** Return an English description of a ::rs_result value. */
LIBRSYNC_EXPORT char const *rs_strerror(rs_result r);
/** Performance statistics from a librsync encoding or decoding operation.
*
* \sa api_stats \sa rs_format_stats() \sa rs_log_stats() */
typedef struct rs_stats {
char const *op; /**< Human-readable name of current operation.
* For example, "delta". */
int lit_cmds; /**< Number of literal commands. */
rs_long_t lit_bytes; /**< Number of literal bytes. */
rs_long_t lit_cmdbytes; /**< Number of bytes used in literal command
* headers. */
rs_long_t copy_cmds, copy_bytes, copy_cmdbytes;
rs_long_t sig_cmds, sig_bytes;
int false_matches;
rs_long_t sig_blocks; /**< Number of blocks described by the
* signature. */
size_t block_len;
rs_long_t in_bytes; /**< Total bytes read from input. */
rs_long_t out_bytes; /**< Total bytes written to output. */
time_t start, end;
} rs_stats_t;
/** MD4 message-digest accumulator.
*
* \sa rs_mdfour(), rs_mdfour_begin(), rs_mdfour_update(), rs_mdfour_result() */
typedef struct rs_mdfour rs_mdfour_t;
LIBRSYNC_EXPORT extern const int RS_MD4_SUM_LENGTH, RS_BLAKE2_SUM_LENGTH;
# define RS_MAX_STRONG_SUM_LENGTH 32
typedef uint32_t rs_weak_sum_t;
typedef unsigned char rs_strong_sum_t[RS_MAX_STRONG_SUM_LENGTH];
LIBRSYNC_EXPORT void rs_mdfour(unsigned char *out, void const *in, size_t);
LIBRSYNC_EXPORT void rs_mdfour_begin( /* @out@ */ rs_mdfour_t *md);
/** Feed some data into the MD4 accumulator.
*
* \param md MD4 accumulator.
*
* \param in_void Data to add.
*
* \param n Number of bytes fed in. */
LIBRSYNC_EXPORT void rs_mdfour_update(rs_mdfour_t *md, void const *in_void,
size_t n);
LIBRSYNC_EXPORT void rs_mdfour_result(rs_mdfour_t *md, unsigned char *out);
/** Return a human-readable representation of statistics.
*
* The string is truncated if it does not fit. 100 characters should be
* sufficient space.
*
* \param stats Statistics from an encoding or decoding operation.
*
* \param buf Buffer to receive result.
*
* \param size Size of buffer.
*
* \return \p buf.
*
* \sa \ref api_stats */
LIBRSYNC_EXPORT char *rs_format_stats(rs_stats_t const *stats, char *buf,
size_t size);
/** Write statistics into the current log as text.
*
* \sa \ref api_stats \sa \ref api_trace */
LIBRSYNC_EXPORT int rs_log_stats(rs_stats_t const *stats);
/** The signature datastructure type. */
typedef struct rs_signature rs_signature_t;
/** Log the rs_signature_delta match stats. */
LIBRSYNC_EXPORT void rs_signature_log_stats(rs_signature_t const *sig);
/** Deep deallocation of checksums. */
LIBRSYNC_EXPORT void rs_free_sumset(rs_signature_t *);
/** Dump signatures to the log. */
LIBRSYNC_EXPORT void rs_sumset_dump(rs_signature_t const *);
/** Description of input and output buffers.
*
* On each call to ::rs_job_iter(), the caller can make available
*
* - #avail_in bytes of input data at #next_in
*
* - #avail_out bytes of output space at #next_out
*
* - or some of both
*
* Buffers must be allocated and passed in by the caller.
*
* On input, the buffers structure must contain the address and length of the
* input and output buffers. The library updates these values to indicate the
* amount of \b remaining buffer. So, on return, #avail_out is not the amount
* of output data produced, but rather the amount of output buffer space still
* available.
*
* This means that the values on return are consistent with the values on
* entry, and suitable to be passed in on a second call, but they don't
* directly tell you how much output data was produced.
*
* Note also that if *#avail_in is nonzero on return, then not all of the input
* data has been consumed. The caller should either provide more output buffer
* space and call ::rs_job_iter() again passing the same #next_in and
* #avail_in, or put the remaining input data into some persistent buffer and
* call rs_job_iter() with it again when there is more output space.
*
* \sa rs_job_iter() */
struct rs_buffers_s {
/** Next input byte.
*
* References a pointer which on entry should point to the start of the
* data to be encoded. Updated to point to the byte after the last one
* consumed. */
char *next_in;
/** Number of bytes available at next_in.
*
* References the length of available input. Updated to be the number of
* unused data bytes, which will be zero if all the input was consumed. May
* be zero if there is no new input, but the caller just wants to drain
* output. */
size_t avail_in;
/** True if there is no more data after this. */
int eof_in;
/** Next output byte should be put there.
*
* References a pointer which on entry points to the start of the output
* buffer. Updated to point to the byte after the last one filled. */
char *next_out;
/** Remaining free space at next_out.
*
* References the size of available output buffer. Updated to the size of
* unused output buffer. */
size_t avail_out;
};
/** \sa ::rs_buffers_s */
typedef struct rs_buffers_s rs_buffers_t;
/** Default block length, if not determined by any other factors.
*
* The 2K default assumes a typical file is about 4MB and should be OK for
* files up to 32G with more than 1GB ram. */
# define RS_DEFAULT_BLOCK_LEN 2048
/** Default minimum strong sum length, if the filesize is unknown.
*
* This is conservative, and should be safe for files less than 45TB with a 2KB
* block_len, assuming no collision attack with crafted data. */
# define RS_DEFAULT_MIN_STRONG_LEN 12
/** Job of work to be done.
*
* Created by functions such as rs_sig_begin(), and then iterated over by
* rs_job_iter().
*
* The contents are opaque to the application, and instances are always
* allocated by the library.
*
* \sa \ref api_streaming \sa rs_job */
typedef struct rs_job rs_job_t;
/** Run a ::rs_job state machine until it blocks (::RS_BLOCKED), returns an
* error, or completes (::RS_DONE).
*
* \param job Description of job state.
*
* \param buffers Pointer to structure describing input and output buffers.
*
* \return The ::rs_result that caused iteration to stop.
*
* \c buffers->eof_in should be true if there is no more data after what's in
* the input buffer. The final block checksum will run across whatever's in
* there, without trying to accumulate anything else.
*
* \sa \ref api_streaming */
LIBRSYNC_EXPORT rs_result rs_job_iter(rs_job_t *job, rs_buffers_t *buffers);
/** Type of application-supplied function for rs_job_drive().
*
* \sa \ref api_pull */
typedef rs_result rs_driven_cb(rs_job_t *job, rs_buffers_t *buf,
void *opaque);
/** Actively process a job, by making callbacks to fill and empty the buffers
* until the job is done. */
LIBRSYNC_EXPORT rs_result rs_job_drive(rs_job_t *job, rs_buffers_t *buf,
rs_driven_cb in_cb, void *in_opaque,
rs_driven_cb out_cb, void *out_opaque);
/** Return a pointer to the statistics in a job. */
LIBRSYNC_EXPORT const rs_stats_t *rs_job_statistics(rs_job_t *job);
/** Deallocate job state. */
LIBRSYNC_EXPORT rs_result rs_job_free(rs_job_t *);
/** Get or check signature arguments for a given file size.
*
* This can be used to get the recommended arguments for generating a
* signature. On calling, old_fsize should be set to the old file size or -1
* for "unknown". The magic and block_len arguments should be set to a valid
* value or 0 for "recommended". The strong_len input should be set to a valid
* value, 0 for "maximum", or -1 for "miniumum". Use strong_len=0 for the best
* protection against active hash collision attacks for the given magic type.
* Use strong_len=-1 for the smallest signature size that is safe against
* random hash collisions for the block_len and old_fsize. Use strong_len=20
* for something probably good enough against attacks with smaller signatures.
* On return the 0 or -1 input args will be set to recommended values and the
* returned result will indicate if any inputs were invalid.
*
* \param old_fsize - the original file size (-1 for "unknown").
*
* \param *magic - the magic type to use (0 for "recommended").
*
* \param *block_len - the block length to use (0 for "recommended").
*
* \param *strong_len - the strongsum length to use (0 for "maximum", -1 for
* "minimum").
*
* \return RS_DONE if all arguments are valid, otherwise an error code. */
LIBRSYNC_EXPORT rs_result rs_sig_args(rs_long_t old_fsize,
rs_magic_number * magic,
size_t *block_len, size_t *strong_len);
/** Start generating a signature.
*
* It's recommended you use rs_sig_args() to get the recommended arguments for
* this based on the original file size.
*
* \return A new rs_job_t into which the old file data can be passed.
*
* \param sig_magic Signature file format to generate (0 for "recommended").
* See ::rs_magic_number.
*
* \param block_len Checksum block size to use (0 for "recommended"). Larger
* values make the signature shorter, and the delta longer.
*
* \param strong_len Strongsum length in bytes to use (0 for "maximum", -1 for
* "minimum"). Smaller values make the signature shorter but increase the risk
* of corruption from hash collisions.
*
* \sa rs_sig_file() */
LIBRSYNC_EXPORT rs_job_t *rs_sig_begin(size_t block_len, size_t strong_len,
rs_magic_number sig_magic);
/** Prepare to compute a streaming delta.
*
* \todo Add a version of this that takes a ::rs_magic_number controlling the
* delta format. */
LIBRSYNC_EXPORT rs_job_t *rs_delta_begin(rs_signature_t *);
/** Read a signature from a file into an ::rs_signature structure in memory.
*
* Once there, it can be used to generate a delta to a newer version of the
* file.
*
* \note After loading the signatures, you must call \ref rs_build_hash_table()
* before you can use them. */
LIBRSYNC_EXPORT rs_job_t *rs_loadsig_begin(rs_signature_t **);
/** Call this after loading a signature to index it.
*
* Use rs_free_sumset() to release it after use. */
LIBRSYNC_EXPORT rs_result rs_build_hash_table(rs_signature_t *sums);
/** Callback used to retrieve parts of the basis file.
*
* \param pos Position where copying should begin.
*
* \param len On input, the amount of data that should be retrieved. Updated to
* show how much is actually available, but should not be greater than the
* input value.
*
* \param buf On input, a buffer of at least \p *len bytes. May be updated to
* point to a buffer allocated by the callback if it prefers. */
typedef rs_result rs_copy_cb(void *opaque, rs_long_t pos, size_t *len,
void **buf);
/** Apply a \a delta to a \a basis file to recreate the \a new file.
*
* This gives you back a ::rs_job_t object, which can be cranked by calling
* rs_job_iter() and updating the stream pointers. When finished, call
* rs_job_free() to dispose of it.
*
* \param copy_cb Callback used to retrieve content from the basis file.
*
* \param copy_arg Opaque environment pointer passed through to the callback.
*
* \todo As output is produced, accumulate the MD4 checksum of the output. Then
* if we find a CHECKSUM command we can check it's contents against the output.
*
* \todo Implement COPY commands.
*
* \sa rs_patch_file() \sa \ref api_streaming */
LIBRSYNC_EXPORT rs_job_t *rs_patch_begin(rs_copy_cb * copy_cb, void *copy_arg);
# ifndef RSYNC_NO_STDIO_INTERFACE
# include <stdio.h>
/** Open a file with special handling for stdin or stdout.
*
* This provides a platform independent way to open large binary files. A
* filename "" or "-" means use stdin for reading, or stdout for writing.
*
* \param filename - The filename to open.
*
* \param mode - fopen style mode string.
*
* \param force - bool to force overwriting of existing files. */
LIBRSYNC_EXPORT FILE *rs_file_open(char const *filename, char const *mode,
int force);
/** Close a file with special handling for stdin or stdout.
*
* This will not actually close the file if it is stdin or stdout.
*
* \param file - the stdio file to close. */
LIBRSYNC_EXPORT int rs_file_close(FILE *file);
/** Get the size of a file.
*
* This provides a platform independent way to get the size of large files. It
* will return -1 if the size cannot be determined because it is not a regular
* file.
*
* \param file - the stdio file to get the size of. */
LIBRSYNC_EXPORT rs_long_t rs_file_size(FILE *file);
/** ::rs_copy_cb that reads from a stdio file. */
LIBRSYNC_EXPORT rs_result rs_file_copy_cb(void *arg, rs_long_t pos, size_t *len,
void **buf);
/** Buffer sizes for file IO.
*
* The default 0 means use the recommended buffer size for the operation being
* performed, any other value will override the recommended sizes. You probably
* only need to change these in testing. */
LIBRSYNC_EXPORT extern int rs_inbuflen, rs_outbuflen;
/** Generate the signature of a basis file, and write it out to another.
*
* It's recommended you use rs_sig_args() to get the recommended arguments for
* this based on the original file size.
*
* \param old_file Stdio readable file whose signature will be generated.
*
* \param sig_file Writable stdio file to which the signature will be written./
*
* \param block_len Checksum block size to use (0 for "recommended"). Larger
* values make the signature shorter, and the delta longer.
*
* \param strong_len Strongsum length in bytes to use (0 for "maximum", -1 for
* "minimum"). Smaller values make the signature shorter but increase the risk
* of corruption from hash collisions.
*
* \param sig_magic Signature file format to generate (0 for "recommended").
* See ::rs_magic_number.
*
* \param stats Optional pointer to receive statistics.
*
* \sa \ref api_whole */
LIBRSYNC_EXPORT rs_result rs_sig_file(FILE *old_file, FILE *sig_file,
size_t block_len, size_t strong_len,
rs_magic_number sig_magic,
rs_stats_t *stats);
/** Load signatures from a signature file into memory.
*
* \param sig_file Readable stdio file from which the signature will be read.
*
* \param sumset on return points to the newly allocated structure.
*
* \param stats Optional pointer to receive statistics.
*
* \sa \ref api_whole */
LIBRSYNC_EXPORT rs_result rs_loadsig_file(FILE *sig_file,
rs_signature_t **sumset,
rs_stats_t *stats);
/** Generate a delta between a signature and a new file into a delta file.
*
* \sa \ref api_whole */
LIBRSYNC_EXPORT rs_result rs_delta_file(rs_signature_t *, FILE *new_file,
FILE *delta_file, rs_stats_t *);
/** Apply a patch, relative to a basis, into a new file.
*
* \sa \ref api_whole */
LIBRSYNC_EXPORT rs_result rs_patch_file(FILE *basis_file, FILE *delta_file,
FILE *new_file, rs_stats_t *);
# endif /* !RSYNC_NO_STDIO_INTERFACE */
# ifdef __cplusplus
} /* extern "C" */
# endif
#endif /* !_RSYNC_H */