thodg/got/lib/object.c

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• Hash : e033d803
  Author :
  Date : 2018-04-23T18:30:26
  

  read tree objects with privsep
  

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• lib/object.c

• /*
   * 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.
   */
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/queue.h>
  #include <sys/uio.h>
  #include <sys/socket.h>
  #include <sys/wait.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <stdint.h>
  #include <sha1.h>
  #include <zlib.h>
  #include <ctype.h>
  #include <limits.h>
  #include <imsg.h>
  
  #include "got_error.h"
  #include "got_object.h"
  #include "got_repository.h"
  
  #include "got_lib_sha1.h"
  #include "got_lib_delta.h"
  #include "got_lib_pack.h"
  #include "got_lib_path.h"
  #include "got_lib_zbuf.h"
  #include "got_lib_object.h"
  #include "got_lib_privsep.h"
  
  #ifndef MIN
  #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
  #endif
  
  #ifndef nitems
  #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
  #endif
  
  #define GOT_OBJ_TAG_COMMIT	"commit"
  #define GOT_OBJ_TAG_TREE	"tree"
  #define GOT_OBJ_TAG_BLOB	"blob"
  
  #define GOT_COMMIT_TAG_TREE		"tree "
  #define GOT_COMMIT_TAG_PARENT		"parent "
  #define GOT_COMMIT_TAG_AUTHOR		"author "
  #define GOT_COMMIT_TAG_COMMITTER	"committer "
  
  const struct got_error *
  got_object_id_str(char **outbuf, struct got_object_id *id)
  {
  	static const size_t len = SHA1_DIGEST_STRING_LENGTH;
  
  	*outbuf = calloc(1, len);
  	if (*outbuf == NULL)
  		return got_error_from_errno();
  
  	if (got_sha1_digest_to_str(id->sha1, *outbuf, len) == NULL) {
  		free(*outbuf);
  		*outbuf = NULL;
  		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
  	}
  
  	return NULL;
  }
  
  int
  got_object_id_cmp(struct got_object_id *id1, struct got_object_id *id2)
  {
  	return memcmp(id1->sha1, id2->sha1, SHA1_DIGEST_LENGTH);
  }
  
  struct got_object_id *
  got_object_id_dup(struct got_object_id *id1)
  {
  	struct got_object_id *id2;
  
  	id2 = malloc(sizeof(*id2));
  	if (id2 == NULL)
  		return NULL;
  	memcpy(id2, id1, sizeof(*id2));
  	return id2;
  }
  
  struct got_object_id *
  got_object_get_id(struct got_object *obj)
  {
  	return got_object_id_dup(&obj->id);
  }
  
  int
  got_object_get_type(struct got_object *obj)
  {
  	switch (obj->type) {
  	case GOT_OBJ_TYPE_COMMIT:
  	case GOT_OBJ_TYPE_TREE:
  	case GOT_OBJ_TYPE_BLOB:
  	case GOT_OBJ_TYPE_TAG:
  		return obj->type;
  	default:
  		abort();
  		break;
  	}
  
  	/* not reached */
  	return 0;
  }
  
  static const struct got_error *
  parse_object_header(struct got_object **obj, char *buf, size_t len)
  {
  	const char *obj_tags[] = {
  		GOT_OBJ_TAG_COMMIT,
  		GOT_OBJ_TAG_TREE,
  		GOT_OBJ_TAG_BLOB
  	};
  	const int obj_types[] = {
  		GOT_OBJ_TYPE_COMMIT,
  		GOT_OBJ_TYPE_TREE,
  		GOT_OBJ_TYPE_BLOB,
  	};
  	int type = 0;
  	size_t size = 0, hdrlen = 0;
  	int i;
  	char *p = strchr(buf, '\0');
  
  	if (p == NULL)
  		return got_error(GOT_ERR_BAD_OBJ_HDR);
  
  	hdrlen = strlen(buf) + 1 /* '\0' */;
  
  	for (i = 0; i < nitems(obj_tags); i++) {
  		const char *tag = obj_tags[i];
  		size_t tlen = strlen(tag);
  		const char *errstr;
  
  		if (strncmp(buf, tag, tlen) != 0)
  			continue;
  
  		type = obj_types[i];
  		if (len <= tlen)
  			return got_error(GOT_ERR_BAD_OBJ_HDR);
  		size = strtonum(buf + tlen, 0, LONG_MAX, &errstr);
  		if (errstr != NULL)
  			return got_error(GOT_ERR_BAD_OBJ_HDR);
  		break;
  	}
  
  	if (type == 0)
  		return got_error(GOT_ERR_BAD_OBJ_HDR);
  
  	*obj = calloc(1, sizeof(**obj));
  	if (*obj == NULL)
  		return got_error_from_errno();
  	(*obj)->type = type;
  	(*obj)->hdrlen = hdrlen;
  	(*obj)->size = size;
  	return NULL;
  }
  
  static const struct got_error *
  read_object_header(struct got_object **obj, FILE *f)
  {
  	const struct got_error *err;
  	struct got_zstream_buf zb;
  	char *buf;
  	const size_t zbsize = 64;
  	size_t outlen, totlen;
  	int i;
  
  	buf = calloc(zbsize, sizeof(char));
  	if (buf == NULL)
  		return got_error_from_errno();
  
  	err = got_inflate_init(&zb, NULL, zbsize);
  	if (err)
  		return err;
  
  	i = 0;
  	totlen = 0;
  	do {
  		err = got_inflate_read(&zb, f, &outlen);
  		if (err)
  			goto done;
  		if (strchr(zb.outbuf, '\0') == NULL) {
  			buf = recallocarray(buf, 1 + i, 2 + i, zbsize);
  			if (buf == NULL) {
  				err = got_error_from_errno();
  				goto done;
  			}
  		}
  		memcpy(buf + totlen, zb.outbuf, outlen);
  		totlen += outlen;
  		i++;
  	} while (strchr(zb.outbuf, '\0') == NULL);
  
  	err = parse_object_header(obj, buf, totlen);
  done:
  	got_inflate_end(&zb);
  	return err;
  }
  
  static void
  read_object_header_privsep_child(int obj_fd, int imsg_fds[2])
  {
  	const struct got_error *err = NULL;
  	struct got_object *obj = NULL;
  	struct imsgbuf ibuf;
  	FILE *f = NULL;
  	int status = 0;
  
  	setproctitle("got: read object header");
  	close(imsg_fds[0]);
  	imsg_init(&ibuf, imsg_fds[1]);
  
  	/* revoke access to most system calls */
  	if (pledge("stdio", NULL) == -1) {
  		err = got_error_from_errno();
  		goto done;
  	}
  
  	f = fdopen(obj_fd, "rb");
  	if (f == NULL) {
  		err = got_error_from_errno();
  		close(obj_fd);
  		goto done;
  	}
  
  	err = read_object_header(&obj, f);
  	if (err)
  		goto done;
  
  	err = got_privsep_send_obj(&ibuf, obj, 0);
  done:
  	if (obj)
  		got_object_close(obj);
  	if (err) {
  		got_privsep_send_error(&ibuf, err);
  		status = 1;
  	}
  	if (f)
  		fclose(f);
  	imsg_clear(&ibuf);
  	close(imsg_fds[1]);
  	_exit(status);
  }
  
  static const struct got_error *
  read_object_header_privsep(struct got_object **obj, int fd)
  {
  	struct imsgbuf parent_ibuf;
  	int imsg_fds[2];
  	const struct got_error *err = NULL;
  	pid_t pid;
  	int child_status;
  
  	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
  		return got_error_from_errno();
  
  	pid = fork();
  	if (pid == -1)
  		return got_error_from_errno();
  	else if (pid == 0) {
  		read_object_header_privsep_child(fd, imsg_fds);
  		/* not reached */
  	}
  
  	close(imsg_fds[1]);
  	imsg_init(&parent_ibuf, imsg_fds[0]);
  	err = got_privsep_recv_obj(obj, &parent_ibuf);
  	imsg_clear(&parent_ibuf);
  	waitpid(pid, &child_status, 0);
  	close(imsg_fds[0]);
  	return err;
  }
  
  static const struct got_error *
  object_path(char **path, struct got_object_id *id, struct got_repository *repo)
  {
  	const struct got_error *err = NULL;
  	char *hex;
  	char *path_objects = got_repo_get_path_objects(repo);
  
  	*path = NULL;
  
  	if (path_objects == NULL)
  		return got_error_from_errno();
  
  	err = got_object_id_str(&hex, id);
  	if (err)
  		return err;
  
  	if (asprintf(path, "%s/%.2x/%s", path_objects,
  	    id->sha1[0], hex + 2) == -1)
  		err = got_error_from_errno();
  
  	free(hex);
  	free(path_objects);
  	return err;
  }
  
  static const struct got_error *
  open_loose_object(int *fd, struct got_object *obj, struct got_repository *repo)
  {
  	const struct got_error *err = NULL;
  	char *path;
  
  	err = object_path(&path, &obj->id, repo);
  	if (err)
  		return err;
  	*fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
  	if (*fd == -1) {
  		err = got_error_from_errno();
  		goto done;
  	}
  done:
  	free(path);
  	return err;
  }
  
  const struct got_error *
  got_object_open(struct got_object **obj, struct got_repository *repo,
      struct got_object_id *id)
  {
  	const struct got_error *err = NULL;
  	char *path;
  	int fd;
  
  	err = object_path(&path, id, repo);
  	if (err)
  		return err;
  
  	fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
  	if (fd == -1) {
  		if (errno != ENOENT) {
  			err = got_error_from_errno();
  			goto done;
  		}
  		err = got_packfile_open_object(obj, id, repo);
  		if (err)
  			goto done;
  		if (*obj == NULL)
  			err = got_error(GOT_ERR_NO_OBJ);
  	} else {
  		err = read_object_header_privsep(obj, fd);
  		if (err)
  			goto done;
  		memcpy((*obj)->id.sha1, id->sha1, SHA1_DIGEST_LENGTH);
  	}
  done:
  	free(path);
  	if (fd != -1)
  		close(fd);
  	return err;
  
  }
  
  const struct got_error *
  got_object_open_by_id_str(struct got_object **obj, struct got_repository *repo,
      const char *id_str)
  {
  	struct got_object_id id;
  
  	if (!got_parse_sha1_digest(id.sha1, id_str))
  		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
  
  	return got_object_open(obj, repo, &id);
  }
  
  void
  got_object_close(struct got_object *obj)
  {
  	if (obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
  		struct got_delta *delta;
  		while (!SIMPLEQ_EMPTY(&obj->deltas.entries)) {
  			delta = SIMPLEQ_FIRST(&obj->deltas.entries);
  			SIMPLEQ_REMOVE_HEAD(&obj->deltas.entries, entry);
  			got_delta_close(delta);
  		}
  	}
  	if (obj->flags & GOT_OBJ_FLAG_PACKED)
  		free(obj->path_packfile);
  	free(obj);
  }
  
  struct got_commit_object *
  got_object_commit_alloc_partial(void)
  {
  	struct got_commit_object *commit;
  
  	commit = calloc(1, sizeof(*commit));
  	if (commit == NULL)
  		return NULL;
  	commit->tree_id = calloc(1, sizeof(*commit->tree_id));
  	if (commit->tree_id == NULL) {
  		free(commit);
  		return NULL;
  	}
  
  	SIMPLEQ_INIT(&commit->parent_ids);
  
  	return commit;
  }
  
  const struct got_error *
  got_object_commit_add_parent(struct got_commit_object *commit,
      const char *id_str)
  {
  	const struct got_error *err = NULL;
  	struct got_parent_id *pid;
  
  	pid = calloc(1, sizeof(*pid));
  	if (pid == NULL)
  		return got_error_from_errno();
  
  	pid->id = calloc(1, sizeof(*pid->id));
  	if (pid->id == NULL) {
  		err = got_error_from_errno();
  		free(pid);
  		return err;
  	}
  
  	if (!got_parse_sha1_digest(pid->id->sha1, id_str)) {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		free(pid->id);
  		free(pid);
  		return err;
  	}
  
  	SIMPLEQ_INSERT_TAIL(&commit->parent_ids, pid, entry);
  	commit->nparents++;
  
  	return NULL;
  }
  
  static const struct got_error *
  parse_commit_object(struct got_commit_object **commit, char *buf, size_t len)
  {
  	const struct got_error *err = NULL;
  	char *s = buf;
  	size_t tlen;
  	ssize_t remain = (ssize_t)len;
   
  	*commit = got_object_commit_alloc_partial();
  	if (*commit == NULL)
  		return got_error_from_errno();
  
  	tlen = strlen(GOT_COMMIT_TAG_TREE);
  	if (strncmp(s, GOT_COMMIT_TAG_TREE, tlen) == 0) {
  		remain -= tlen;
  		if (remain < SHA1_DIGEST_STRING_LENGTH) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		s += tlen;
  		if (!got_parse_sha1_digest((*commit)->tree_id->sha1, s)) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		remain -= SHA1_DIGEST_STRING_LENGTH;
  		s += SHA1_DIGEST_STRING_LENGTH;
  	} else {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		goto done;
  	}
  
  	tlen = strlen(GOT_COMMIT_TAG_PARENT);
  	while (strncmp(s, GOT_COMMIT_TAG_PARENT, tlen) == 0) {
  		remain -= tlen;
  		if (remain < SHA1_DIGEST_STRING_LENGTH) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		s += tlen;
  		err = got_object_commit_add_parent(*commit, s);
  		if (err)
  			goto done;
  
  		remain -= SHA1_DIGEST_STRING_LENGTH;
  		s += SHA1_DIGEST_STRING_LENGTH;
  	}
  
  	tlen = strlen(GOT_COMMIT_TAG_AUTHOR);
  	if (strncmp(s, GOT_COMMIT_TAG_AUTHOR, tlen) == 0) {
  		char *p;
  
  		remain -= tlen;
  		if (remain <= 0) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		s += tlen;
  		p = strchr(s, '\n');
  		if (p == NULL) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		*p = '\0';
  		(*commit)->author = strdup(s);
  		if ((*commit)->author == NULL) {
  			err = got_error_from_errno();
  			goto done;
  		}
  		s += strlen((*commit)->author) + 1;
  		remain -= strlen((*commit)->author) + 1;
  	}
  
  	tlen = strlen(GOT_COMMIT_TAG_COMMITTER);
  	if (strncmp(s, GOT_COMMIT_TAG_COMMITTER, tlen) == 0) {
  		char *p;
  
  		remain -= tlen;
  		if (remain <= 0) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		s += tlen;
  		p = strchr(s, '\n');
  		if (p == NULL) {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		*p = '\0';
  		(*commit)->committer = strdup(s);
  		if ((*commit)->committer == NULL) {
  			err = got_error_from_errno();
  			goto done;
  		}
  		s += strlen((*commit)->committer) + 1;
  		remain -= strlen((*commit)->committer) + 1;
  	}
  
  	(*commit)->logmsg = strndup(s, remain);
  	if ((*commit)->logmsg == NULL) {
  		err = got_error_from_errno();
  		goto done;
  	}
  done:
  	if (err) {
  		got_object_commit_close(*commit);
  		*commit = NULL;
  	}
  	return err;
  }
  
  static void
  tree_entry_close(struct got_tree_entry *te)
  {
  	free(te->id);
  	free(te->name);
  	free(te);
  }
  
  struct got_tree_entry *
  got_alloc_tree_entry_partial(void)
  {
  	struct got_tree_entry *te;
  
  	te = calloc(1, sizeof(*te));
  	if (te == NULL)
  		return NULL;
  
  	te->id = calloc(1, sizeof(*te->id));
  	if (te->id == NULL) {
  		free(te);
  		te = NULL;
  	}
  	return te;
  }
  
  static const struct got_error *
  parse_tree_entry(struct got_tree_entry **te, size_t *elen, char *buf,
      size_t maxlen)
  {
  	char *p = buf, *space;
  	const struct got_error *err = NULL;
  
  	*te = got_alloc_tree_entry_partial();
  	if (*te == NULL)
  		return got_error_from_errno();
  
  	*elen = strlen(buf) + 1;
  	if (*elen > maxlen) {
  		free(*te);
  		*te = NULL;
  		return got_error(GOT_ERR_BAD_OBJ_DATA);
  	}
  
  	space = strchr(buf, ' ');
  	if (space == NULL) {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		free(*te);
  		*te = NULL;
  		return err;
  	}
  	while (*p != ' ') {
  		if (*p < '0' && *p > '7') {
  			err = got_error(GOT_ERR_BAD_OBJ_DATA);
  			goto done;
  		}
  		(*te)->mode <<= 3;
  		(*te)->mode |= *p - '0';
  		p++;
  	}
  
  	(*te)->name = strdup(space + 1);
  	if (*elen > maxlen || maxlen - *elen < SHA1_DIGEST_LENGTH) {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		goto done;
  	}
  	buf += strlen(buf) + 1;
  	memcpy((*te)->id->sha1, buf, SHA1_DIGEST_LENGTH);
  	*elen += SHA1_DIGEST_LENGTH;
  done:
  	if (err) {
  		tree_entry_close(*te);
  		*te = NULL;
  	}
  	return err;
  }
  
  static const struct got_error *
  parse_tree_object(struct got_tree_object **tree, uint8_t *buf, size_t len)
  {
  	const struct got_error *err;
  	size_t remain = len;
  
  	*tree = calloc(1, sizeof(**tree));
  	if (*tree == NULL)
  		return got_error_from_errno();
  
  	SIMPLEQ_INIT(&(*tree)->entries);
  
  	while (remain > 0) {
  		struct got_tree_entry *te;
  		size_t elen;
  
  		err = parse_tree_entry(&te, &elen, buf, remain);
  		if (err)
  			return err;
  		(*tree)->nentries++;
  		SIMPLEQ_INSERT_TAIL(&(*tree)->entries, te, entry);
  		buf += elen;
  		remain -= elen;
  	}
  
  	if (remain != 0) {
  		got_object_tree_close(*tree);
  		return got_error(GOT_ERR_BAD_OBJ_DATA);
  	}
  
  	return NULL;
  }
  
  static const struct got_error *
  read_to_mem(uint8_t **outbuf, size_t *outlen, FILE *f)
  {
  	const struct got_error *err = NULL;
  	static const size_t blocksize = 512;
  	size_t n, total, remain;
  	uint8_t *buf;
  
  	*outbuf = NULL;
  	*outlen = 0;
  
  	buf = calloc(1, blocksize);
  	if (buf == NULL)
  		return got_error_from_errno();
  
  	remain = blocksize;
  	total = 0;
  	while (1) {
  		if (remain == 0) {
  			uint8_t *newbuf;
  			newbuf = reallocarray(buf, 1, total + blocksize);
  			if (newbuf == NULL) {
  				err = got_error_from_errno();
  				goto done;
  			}
  			buf = newbuf;
  			remain += blocksize;
  		}
  		n = fread(buf + total, 1, remain, f);
  		if (n == 0) {
  			if (ferror(f)) {
  				err = got_ferror(f, GOT_ERR_IO);
  				goto done;
  			}
  			break; /* EOF */
  		}
  		remain -= n;
  		total += n;
  	};
  
  done:
  	if (err == NULL) {
  		*outbuf = buf;
  		*outlen = total;
  	} else
  		free(buf);
  	return err;
  }
  
  static const struct got_error *
  read_commit_object(struct got_commit_object **commit, struct got_object *obj,
      FILE *f)
  {
  	const struct got_error *err = NULL;
  	size_t len;
  	uint8_t *p;
  
  	if (obj->flags & GOT_OBJ_FLAG_PACKED)
  		err = read_to_mem(&p, &len, f);
  	else
  		err = got_inflate_to_mem(&p, &len, f);
  	if (err)
  		return err;
  
  	if (len < obj->hdrlen + obj->size) {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		goto done;
  	}
  
  	/* Skip object header. */
  	len -= obj->hdrlen;
  	err = parse_commit_object(commit, p + obj->hdrlen, len);
  	free(p);
  done:
  	return err;
  }
  
  static void
  read_commit_object_privsep_child(struct got_object *obj, int obj_fd,
      int imsg_fds[2])
  {
  	const struct got_error *err = NULL;
  	struct got_commit_object *commit = NULL;
  	struct imsgbuf ibuf;
  	FILE *f = NULL;
  	int status = 0;
  
  	setproctitle("got: read commit object");
  	close(imsg_fds[0]);
  	imsg_init(&ibuf, imsg_fds[1]);
  
  	/* revoke access to most system calls */
  	if (pledge("stdio", NULL) == -1) {
  		err = got_error_from_errno();
  		goto done;
  	}
  
  	f = fdopen(obj_fd, "rb");
  	if (f == NULL) {
  		err = got_error_from_errno();
  		close(obj_fd);
  		goto done;
  	}
  
  	err = read_commit_object(&commit, obj, f);
  	if (err)
  		goto done;
  
  	err = got_privsep_send_commit_obj(&ibuf, commit);
  done:
  	if (commit)
  		got_object_commit_close(commit);
  	if (err) {
  		got_privsep_send_error(&ibuf, err);
  		status = 1;
  	}
  	if (f)
  		fclose(f);
  	imsg_clear(&ibuf);
  	close(imsg_fds[1]);
  	_exit(status);
  }
  
  static const struct got_error *
  read_commit_object_privsep(struct got_commit_object **commit,
      struct got_repository *repo, struct got_object *obj, int fd)
  {
  	const struct got_error *err = NULL;
  	struct imsgbuf parent_ibuf;
  	int imsg_fds[2];
  	pid_t pid;
  	int child_status;
  
  	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
  		return got_error_from_errno();
  
  	pid = fork();
  	if (pid == -1)
  		return got_error_from_errno();
  	else if (pid == 0) {
  		read_commit_object_privsep_child(obj, fd, imsg_fds);
  		/* not reached */
  	}
  
  	close(imsg_fds[1]);
  	imsg_init(&parent_ibuf, imsg_fds[0]);
  	err = got_privsep_recv_commit_obj(commit, &parent_ibuf);
  	imsg_clear(&parent_ibuf);
  	waitpid(pid, &child_status, 0);
  	close(imsg_fds[0]);
  	return err;
  }
  
  const struct got_error *
  got_object_commit_open(struct got_commit_object **commit,
      struct got_repository *repo, struct got_object *obj)
  {
  	const struct got_error *err = NULL;
  
  	if (obj->type != GOT_OBJ_TYPE_COMMIT)
  		return got_error(GOT_ERR_OBJ_TYPE);
  
  	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
  		uint8_t *buf;
  		size_t len;
  		err = got_packfile_extract_object_to_mem(&buf, &len, obj, repo);
  		if (err)
  			return err;
  		obj->size = len;
  		err = parse_commit_object(commit, buf, len);
  		free(buf);
  	} else {
  		int fd;
  		err = open_loose_object(&fd, obj, repo);
  		if (err)
  			return err;
  		err = read_commit_object_privsep(commit, repo, obj, fd);
  		close(fd);
  	}
  	return err;
  }
  
  void
  got_object_commit_close(struct got_commit_object *commit)
  {
  	struct got_parent_id *pid;
  
  	while (!SIMPLEQ_EMPTY(&commit->parent_ids)) {
  		pid = SIMPLEQ_FIRST(&commit->parent_ids);
  		SIMPLEQ_REMOVE_HEAD(&commit->parent_ids, entry);
  		free(pid->id);
  		free(pid);
  	}
  
  	free(commit->tree_id);
  	free(commit->author);
  	free(commit->committer);
  	free(commit->logmsg);
  	free(commit);
  }
  
  static const struct got_error *
  read_tree_object(struct got_tree_object **tree, struct got_object *obj, FILE *f)
  {
  	const struct got_error *err = NULL;
  	size_t len;
  	uint8_t *p;
  
  	if (obj->flags & GOT_OBJ_FLAG_PACKED)
  		err = read_to_mem(&p, &len, f);
  	else
  		err = got_inflate_to_mem(&p, &len, f);
  	if (err)
  		return err;
  
  	if (len < obj->hdrlen + obj->size) {
  		err = got_error(GOT_ERR_BAD_OBJ_DATA);
  		goto done;
  	}
  
  	/* Skip object header. */
  	len -= obj->hdrlen;
  	err = parse_tree_object(tree, p + obj->hdrlen, len);
  	free(p);
  done:
  	return err;
  }
  
  static void
  read_tree_object_privsep_child(struct got_object *obj, int obj_fd,
      int imsg_fds[2])
  {
  	const struct got_error *err = NULL;
  	struct got_tree_object *tree = NULL;
  	struct imsgbuf ibuf;
  	FILE *f = NULL;
  	int status = 0;
  
  	setproctitle("got: read tree object");
  	close(imsg_fds[0]);
  	imsg_init(&ibuf, imsg_fds[1]);
  
  	/* revoke access to most system calls */
  	if (pledge("stdio", NULL) == -1) {
  		err = got_error_from_errno();
  		goto done;
  	}
  
  	f = fdopen(obj_fd, "rb");
  	if (f == NULL) {
  		err = got_error_from_errno();
  		close(obj_fd);
  		goto done;
  	}
  
  	err = read_tree_object(&tree, obj, f);
  	if (err)
  		goto done;
  
  	err = got_privsep_send_tree_obj(&ibuf, tree);
  done:
  	if (tree)
  		got_object_tree_close(tree);
  	if (err) {
  		got_privsep_send_error(&ibuf, err);
  		status = 1;
  	}
  	if (f)
  		fclose(f);
  	imsg_clear(&ibuf);
  	close(imsg_fds[1]);
  	_exit(status);
  }
  
  static const struct got_error *
  read_tree_object_privsep(struct got_tree_object **tree, struct got_object *obj,
      int fd)
  {
  	const struct got_error *err = NULL;
  	struct imsgbuf parent_ibuf;
  	int imsg_fds[2];
  	pid_t pid;
  	int child_status;
  
  	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1)
  		return got_error_from_errno();
  
  	pid = fork();
  	if (pid == -1)
  		return got_error_from_errno();
  	else if (pid == 0) {
  		read_tree_object_privsep_child(obj, fd, imsg_fds);
  		/* not reached */
  	}
  
  	close(imsg_fds[1]);
  	imsg_init(&parent_ibuf, imsg_fds[0]);
  	err = got_privsep_recv_tree_obj(tree, &parent_ibuf);
  	imsg_clear(&parent_ibuf);
  	waitpid(pid, &child_status, 0);
  	close(imsg_fds[0]);
  	return err;
  }
  
  const struct got_error *
  got_object_tree_open(struct got_tree_object **tree,
      struct got_repository *repo, struct got_object *obj)
  {
  	const struct got_error *err = NULL;
  
  	if (obj->type != GOT_OBJ_TYPE_TREE)
  		return got_error(GOT_ERR_OBJ_TYPE);
  
  	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
  		uint8_t *buf;
  		size_t len;
  		err = got_packfile_extract_object_to_mem(&buf, &len, obj, repo);
  		if (err)
  			return err;
  		obj->size = len;
  		err = parse_tree_object(tree, buf, len);
  		free(buf);
  	} else {
  		int fd;
  		err = open_loose_object(&fd, obj, repo);
  		if (err)
  			return err;
  		err = read_tree_object_privsep(tree, obj, fd);
  		close(fd);
  	}
  	return err;
  }
  
  void
  got_object_tree_close(struct got_tree_object *tree)
  {
  	struct got_tree_entry *te;
  
  	while (!SIMPLEQ_EMPTY(&tree->entries)) {
  		te = SIMPLEQ_FIRST(&tree->entries);
  		SIMPLEQ_REMOVE_HEAD(&tree->entries, entry);
  		tree_entry_close(te);
  	}
  
  	free(tree);
  }
  
  const struct got_error *
  got_object_blob_open(struct got_blob_object **blob,
      struct got_repository *repo, struct got_object *obj, size_t blocksize)
  {
  	const struct got_error *err = NULL;
  
  	if (obj->type != GOT_OBJ_TYPE_BLOB)
  		return got_error(GOT_ERR_OBJ_TYPE);
  
  	if (blocksize < obj->hdrlen)
  		return got_error(GOT_ERR_NO_SPACE);
  
  	*blob = calloc(1, sizeof(**blob));
  	if (*blob == NULL)
  		return got_error_from_errno();
  
  	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
  		(*blob)->read_buf = calloc(1, blocksize);
  		if ((*blob)->read_buf == NULL) {
  			err = got_error_from_errno();
  			free(*blob);
  			*blob = NULL;
  			return err;
  		}
  		err = got_packfile_extract_object(&((*blob)->f), obj, repo);
  		if (err) {
  			free((*blob)->read_buf);
  			free(*blob);
  			*blob = NULL;
  			return err;
  		}
  	} else {
  		int fd;
  		err = open_loose_object(&fd, obj, repo);
  		if (err) {
  			free(*blob);
  			*blob = NULL;
  			return err;
  		}
  		(*blob)->f = fdopen(fd, "rb");
  		if ((*blob)->f == NULL) {
  			free(*blob);
  			*blob = NULL;
  			close(fd);
  			return err;
  		}
  
  		err = got_inflate_init(&(*blob)->zb, NULL, blocksize);
  		if (err != NULL) {
  			fclose((*blob)->f);
  			free(*blob);
  			*blob = NULL;
  			return err;
  		}
  
  		(*blob)->read_buf = (*blob)->zb.outbuf;
  		(*blob)->flags |= GOT_BLOB_F_COMPRESSED;
  	}
  
  	(*blob)->hdrlen = obj->hdrlen;
  	(*blob)->blocksize = blocksize;
  	memcpy(&(*blob)->id.sha1, obj->id.sha1, SHA1_DIGEST_LENGTH);
  
  	return err;
  }
  
  void
  got_object_blob_close(struct got_blob_object *blob)
  {
  	if (blob->flags & GOT_BLOB_F_COMPRESSED)
  		got_inflate_end(&blob->zb);
  	else
  		free(blob->read_buf);
  	fclose(blob->f);
  	free(blob);
  }
  
  char *
  got_object_blob_id_str(struct got_blob_object *blob, char *buf, size_t size)
  {
  	return got_sha1_digest_to_str(blob->id.sha1, buf, size);
  }
  
  size_t
  got_object_blob_get_hdrlen(struct got_blob_object *blob)
  {
  	return blob->hdrlen;
  }
  
  const uint8_t *
  got_object_blob_get_read_buf(struct got_blob_object *blob)
  {
  	return blob->read_buf;
  }
  
  const struct got_error *
  got_object_blob_read_block(size_t *outlenp, struct got_blob_object *blob)
  {
  	size_t n;
  
  	if (blob->flags & GOT_BLOB_F_COMPRESSED)
  		return got_inflate_read(&blob->zb, blob->f, outlenp);
  
  	n = fread(blob->read_buf, 1, blob->blocksize, blob->f);
  	if (n == 0 && ferror(blob->f))
  		return got_ferror(blob->f, GOT_ERR_IO);
  	*outlenp = n;
  	return NULL;
  }
  

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