thodg/got/lib/got_lib_privsep.h

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  Commit

• Author : Stefan Sperling
  Date : 2018-09-09 12:44:15
  Hash : f0b0c746
  Message : tweak comments in got_lib_privsep.h

• lib/got_lib_privsep.h

• /*
   * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  /*
   * All code runs under the same UID but sensitive code paths are
   * run in a separate process with tighter pledge(2) promises.
   * Data is communicated between processes via imsg_flush(3) and imsg_read(3).
   * This behaviour is transparent to users of the library.
   *
   * We generally transmit data in imsg buffers, split across several messages
   * if necessary. File descriptors are used in cases where this is impractical,
   * such as when accessing pack files or when transferring large blobs.
   *
   * We exec(2) after a fork(2). Parts of our library functionality are
   * accessible via separate executables in a libexec directory.
   */
  
  #define GOT_IMSG_FD_CHILD (STDERR_FILENO + 1)
  
  #ifndef GOT_LIBEXECDIR
  #define GOT_LIBEXECDIR /usr/libexec
  #endif
  
  /* Names of helper programs in libexec directory */
  #define GOT_PROG_READ_OBJECT	got-read-object
  #define GOT_PROG_READ_TREE	got-read-tree
  #define GOT_PROG_READ_COMMIT	got-read-commit
  #define GOT_PROG_READ_BLOB	got-read-blob
  
  #define GOT_STRINGIFY(x) #x
  #define GOT_STRINGVAL(x) GOT_STRINGIFY(x)
  
  /* Paths to helper programs in libexec directory */
  #define GOT_PATH_PROG_READ_OBJECT \
  	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_OBJECT)
  #define GOT_PATH_PROG_READ_TREE \
  	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_TREE)
  #define GOT_PATH_PROG_READ_COMMIT \
  	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_COMMIT)
  #define GOT_PATH_PROG_READ_BLOB \
  	GOT_STRINGVAL(GOT_LIBEXECDIR) "/" GOT_STRINGVAL(GOT_PROG_READ_BLOB)
  
  enum got_imsg_type {
  	/* An error occured while processing a request. */
  	GOT_IMSG_ERROR,
  
  	/* Stop the child process. */
  	GOT_IMSG_STOP,
  
  	/*
  	 * Messages concerned with read access to objects in a repository.
  	 * Object and pack files are opened by the main process, where
  	 * data may be read as a byte string but without any interpretation.
  	 * Decompression and parsing of object and pack files occurs in a
  	 * separate process which runs under pledge("stdio recvfd").
  	 * This sandboxes our own repository parsing code, as well as zlib.
  	 */
  	GOT_IMSG_OBJECT_REQUEST,
  	GOT_IMSG_OBJECT,
  	GOT_IMSG_COMMIT_REQUEST,
  	GOT_IMSG_COMMIT,
  	GOT_IMSG_TREE_REQUEST,
  	GOT_IMSG_TREE,
  	GOT_IMSG_TREE_ENTRY,
  	GOT_IMSG_BLOB_REQUEST,
  	GOT_IMSG_BLOB_OUTFD,
  	GOT_IMSG_BLOB,
  	/* Messages for transmitting deltas and associated delta streams: */
  	GOT_IMSG_DELTA,
  	GOT_IMSG_DELTA_STREAM,
  };
  
  /* Structure for GOT_IMSG_ERROR. */
  struct got_imsg_error {
  	int code; /* an error code from got_error.h */
  	int errno_code; /* in case code equals GOT_ERR_ERRNO */
  };
  
  /* Structure for GOT_IMSG_DELTA data. */
  struct got_imsg_delta {
  	/* These fields are the same as in struct got_delta. */
  	off_t offset;
  	size_t tslen;
  	int type;
  	size_t size;
  	off_t data_offset;
  	size_t delta_len;
  
  	/*
  	 * Followed by delta stream in remaining bytes of imsg buffer.
  	 * If delta_len exceeds imsg buffer length, followed by one or
  	 * more DELTA_STREAM messages until delta_len bytes of delta
  	 * stream have been transmitted.
  	 */
  };
  
  /* Structure for GOT_IMSG_DELTA_STREAM data. */
  struct got_imsg_delta_stream {
  	/*
  	 * Empty since the following is implied:
  	 * Read additional delta stream data from imsg buffer.
  	 */
  };
  
  /*
   * Structure for GOT_IMSG_TREE_REQUEST, GOT_IMSG_COMMIT_REQUEST,
   * and GOT_IMSG_OBJECT data.
   */
  struct got_imsg_object {
  	/* These fields are the same as in struct got_object. */
  	int type;
  	int flags;
  	size_t hdrlen;
  	size_t size;
  
  	int ndeltas; /* this many GOT_IMSG_DELTA messages follow */
  };
  
  /* Structure for GOT_IMSG_COMMIT data. */
  struct got_imsg_commit_object {
  	uint8_t tree_id[SHA1_DIGEST_LENGTH];
  	size_t author_len;
  	struct tm tm_author;
  	size_t committer_len;
  	struct tm tm_committer;
  	size_t logmsg_len;
  	int nparents;
  
  	/*
  	 * Followed by author_len + committer_len + logmsg_len data bytes
  	 */
  
  	/* Followed by 'nparents' SHA1_DIGEST_LENGTH length strings */
  
  	/* XXX should use more messages to support very large log messages */
  } __attribute__((__packed__));
  
  
  /* Structure for GOT_IMSG_TREE_ENTRY. */
  struct got_imsg_tree_entry {
  	char id[SHA1_DIGEST_LENGTH];
  	mode_t mode;
  	/* Followed by entry's name in remaining data of imsg buffer. */
  } __attribute__((__packed__));
  
  /* Structure for GOT_IMSG_TREE_OBJECT_REPLY data. */
  struct got_imsg_tree_object {
  	int nentries; /* This many TREE_ENTRY messages follow. */
  };
  
  /* Structure for GOT_IMSG_BLOB. */
  struct got_imsg_blob {
  	size_t size;
  };
  
  const struct got_error *got_privsep_send_stop(int);
  const struct got_error *got_privsep_recv_imsg(struct imsg *, struct imsgbuf *,
      size_t);
  void got_privsep_send_error(struct imsgbuf *, const struct got_error *);
  const struct got_error *got_privsep_send_obj_req(struct imsgbuf *, int,
      struct got_object *);
  const struct got_error *got_privsep_send_blob_req(struct imsgbuf *, int, int);
  const struct got_error *got_privsep_send_obj(struct imsgbuf *,
      struct got_object *, int);
  const struct got_error *got_privsep_recv_obj(struct got_object **,
      struct imsgbuf *);
  const struct got_error *got_privsep_send_commit(struct imsgbuf *,
      struct got_commit_object *);
  const struct got_error *got_privsep_recv_commit(struct got_commit_object **,
      struct imsgbuf *);
  const struct got_error *got_privsep_recv_tree(struct got_tree_object **,
      struct imsgbuf *);
  const struct got_error *got_privsep_send_tree(struct imsgbuf *,
      struct got_tree_object *);
  const struct got_error *got_privsep_send_blob(struct imsgbuf *, size_t);
  const struct got_error *got_privsep_recv_blob(size_t *, struct imsgbuf *);