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thodg/got/lib/object.c

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  • Author : Stefan Sperling
    Date : 2018-07-13 00:30:22
    Hash : 062ebb78
    Message : replace some calloc() with malloc() in object.c

  • 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 <time.h>
    
    #include "got_error.h"
    #include "got_object.h"
    #include "got_repository.h"
    #include "got_opentemp.h"
    
    #include "got_lib_sha1.h"
    #include "got_lib_delta.h"
    #include "got_lib_pack.h"
    #include "got_lib_path.h"
    #include "got_lib_inflate.h"
    #include "got_lib_object.h"
    #include "got_lib_privsep.h"
    #include "got_lib_repository.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 = malloc(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);
    }
    
    const struct got_error *
    got_object_get_id_str(char **outbuf, struct got_object *obj)
    {
    	return got_object_id_str(outbuf, &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, int fd)
    {
    	const struct got_error *err;
    	struct got_zstream_buf zb;
    	char *buf;
    	const size_t zbsize = 64;
    	size_t outlen, totlen;
    	int i;
    
    	buf = malloc(zbsize);
    	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_fd(&zb, fd, &outlen);
    		if (err)
    			goto done;
    		if (strchr(zb.outbuf, '\0') == NULL) {
    			buf = reallocarray(buf, 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;
    	int status = 0;
    
    	setproctitle("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;
    	}
    
    	err = read_object_header(&obj, obj_fd);
    	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;
    	}
    	close(obj_fd);
    	imsg_clear(&ibuf);
    	close(imsg_fds[1]);
    	_exit(status);
    }
    
    static const struct got_error *
    wait_for_child(pid_t pid)
    {
    	int child_status;
    
    	waitpid(pid, &child_status, 0);
    
    	if (!WIFEXITED(child_status))
    		return got_error(GOT_ERR_PRIVSEP_DIED);
    
    	if (WEXITSTATUS(child_status) != 0)
    		return got_error(GOT_ERR_PRIVSEP_EXIT);
    
    	return NULL;
    }
    
    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, *err_child = NULL;
    	pid_t pid;
    
    	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);
    	err_child = wait_for_child(pid);
    	close(imsg_fds[0]);
    	return err ? err : err_child;
    }
    
    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;
    
    	*obj = got_repo_get_cached_object(repo, id);
    	if (*obj != NULL) {
    		(*obj)->refcnt++;
    		return NULL;
    	}
    
    	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);
    	}
    
    	if (err == NULL) {
    		(*obj)->refcnt++;
    		err = got_repo_cache_object(repo, id, *obj);
    	}
    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->refcnt > 0) {
    		obj->refcnt--;
    		if (obj->refcnt > 0)
    			return;
    	}
    
    	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_open_as_commit(struct got_commit_object **commit,
        struct got_repository *repo, struct got_object_id *id)
    {
    	const struct got_error *err;
    	struct got_object *obj;
    
    	*commit = NULL;
    
    	err = got_object_open(&obj, repo, id);
    	if (err)
    		return err;
    	if (got_object_get_type(obj) != GOT_OBJ_TYPE_COMMIT) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	err = got_object_commit_open(commit, repo, obj);
    done:
    	got_object_close(obj);
    	return err;
    }
    
    const struct got_error *
    got_object_qid_alloc(struct got_object_qid **qid, struct got_object_id *id)
    {
    	const struct got_error *err = NULL;
    
    	*qid = calloc(1, sizeof(**qid));
    	if (*qid == NULL)
    		return got_error_from_errno();
    
    	(*qid)->id = got_object_id_dup(id);
    	if ((*qid)->id == NULL) {
    		err = got_error_from_errno();
    		free(*qid);
    		*qid = NULL;
    		return err;
    	}
    
    	return NULL;
    }
    
    void
    got_object_qid_free(struct got_object_qid *qid)
    {
    	free(qid->id);
    	free(qid);
    }
    
    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_object_qid *qid;
    
    	qid = malloc(sizeof(*qid));
    	if (qid == NULL)
    		return got_error_from_errno();
    
    	qid->id = malloc(sizeof(*qid->id));
    	if (qid->id == NULL) {
    		err = got_error_from_errno();
    		free(qid);
    		return err;
    	}
    
    	if (!got_parse_sha1_digest(qid->id->sha1, id_str)) {
    		err = got_error(GOT_ERR_BAD_OBJ_DATA);
    		free(qid->id);
    		free(qid);
    		return err;
    	}
    
    	SIMPLEQ_INSERT_TAIL(&commit->parent_ids, qid, entry);
    	commit->nparents++;
    
    	return NULL;
    }
    
    static const struct got_error *
    parse_gmtoff(time_t *gmtoff, const char *tzstr)
    {
    	int sign = 1;
    	const char *p = tzstr;
    	time_t h, m;
    
    	*gmtoff = 0;
    
    	if (*p == '-')
    		sign = -1;
    	else if (*p != '+')
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    	p++;
    	if (!isdigit(*p) && !isdigit(*(p + 1)))
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    	h = (((*p - '0') * 10) + (*(p + 1) - '0'));
    
    	p += 2;
    	if (!isdigit(*p) && !isdigit(*(p + 1)))
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    	m = ((*p - '0') * 10) + (*(p + 1) - '0');
    
    	*gmtoff = (h * 60 * 60 + m * 60) * sign;
    	return NULL;
    }
    
    static const struct got_error *
    parse_commit_time(struct tm *tm, char *committer)
    {
    	const struct got_error *err = NULL;
    	const char *errstr;
    	char *space, *tzstr;
    	time_t gmtoff;
    	time_t time;
    
    	/* Parse and strip off trailing timezone indicator string. */
    	space = strrchr(committer, ' ');
    	if (space == NULL)
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    	tzstr = strdup(space + 1);
    	if (tzstr == NULL)
    		return got_error_from_errno();
    	err = parse_gmtoff(&gmtoff, tzstr);
    	free(tzstr);
    	if (err)
    		return err;
    	*space = '\0';
    
    	/* Timestamp is separated from committer name + email by space. */
    	space = strrchr(committer, ' ');
    	if (space == NULL)
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    
    	/* Timestamp parsed here is expressed in comitter's local time. */
    	time = strtonum(space + 1, 0, INT64_MAX, &errstr);
    	if (errstr)
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    
    	/* Express the time stamp in UTC. */
    	memset(tm, 0, sizeof(*tm));
    	time -= gmtoff;
    	if (localtime_r(&time, tm) == NULL)
    		return got_error_from_errno();
    	tm->tm_gmtoff = gmtoff;
    
    	/* Strip off parsed time information, leaving just author and email. */
    	*space = '\0';
    
    	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;
    		size_t slen;
    
    		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';
    		slen = strlen(s);
    		err = parse_commit_time(&(*commit)->tm_author, s);
    		if (err)
    			goto done;
    		(*commit)->author = strdup(s);
    		if ((*commit)->author == NULL) {
    			err = got_error_from_errno();
    			goto done;
    		}
    		s += slen + 1;
    		remain -= slen + 1;
    	}
    
    	tlen = strlen(GOT_COMMIT_TAG_COMMITTER);
    	if (strncmp(s, GOT_COMMIT_TAG_COMMITTER, tlen) == 0) {
    		char *p;
    		size_t slen;
    
    		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';
    		slen = strlen(s);
    		err = parse_commit_time(&(*commit)->tm_committer, s);
    		if (err)
    			goto done;
    		(*commit)->committer = strdup(s);
    		if ((*commit)->committer == NULL) {
    			err = got_error_from_errno();
    			goto done;
    		}
    		s += slen + 1;
    		remain -= slen + 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.head);
    
    	while (remain > 0) {
    		struct got_tree_entry *te;
    		size_t elen;
    
    		err = parse_tree_entry(&te, &elen, buf, remain);
    		if (err)
    			return err;
    		(*tree)->entries.nentries++;
    		SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, 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 = malloc(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("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(&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, *err_child = NULL;
    	struct imsgbuf parent_ibuf;
    	int imsg_fds[2];
    	pid_t pid;
    
    	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(commit, &parent_ibuf);
    	imsg_clear(&parent_ibuf);
    	err_child = wait_for_child(pid);
    	close(imsg_fds[0]);
    	return err ? err : err_child;
    }
    
    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;
    
    	*commit = got_repo_get_cached_commit(repo, &obj->id);
    	if (*commit != NULL) {
    		(*commit)->refcnt++;
    		return 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);
    	}
    
    	if (err == NULL) {
    		(*commit)->refcnt++;
    		err = got_repo_cache_commit(repo, &obj->id, *commit);
    	}
    
    	return err;
    }
    
    void
    got_object_commit_close(struct got_commit_object *commit)
    {
    	struct got_object_qid *qid;
    
    	if (commit->refcnt > 0) {
    		commit->refcnt--;
    		if (commit->refcnt > 0)
    			return;
    	}
    
    	while (!SIMPLEQ_EMPTY(&commit->parent_ids)) {
    		qid = SIMPLEQ_FIRST(&commit->parent_ids);
    		SIMPLEQ_REMOVE_HEAD(&commit->parent_ids, entry);
    		free(qid->id);
    		free(qid);
    	}
    
    	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("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(&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, *err_child = NULL;
    	struct imsgbuf parent_ibuf;
    	int imsg_fds[2];
    	pid_t pid;
    
    	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(tree, &parent_ibuf);
    	imsg_clear(&parent_ibuf);
    	err_child = wait_for_child(pid);
    	close(imsg_fds[0]);
    	return err ? err : err_child;
    }
    
    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;
    
    	*tree = got_repo_get_cached_tree(repo, &obj->id);
    	if (*tree != NULL) {
    		(*tree)->refcnt++;
    		return 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);
    	}
    
    	if (err == NULL) {
    		(*tree)->refcnt++;
    		err = got_repo_cache_tree(repo, &obj->id, *tree);
    	}
    
    	return err;
    }
    
    const struct got_error *
    got_object_open_as_tree(struct got_tree_object **tree,
        struct got_repository *repo, struct got_object_id *id)
    {
    	const struct got_error *err;
    	struct got_object *obj;
    
    	*tree = NULL;
    
    	err = got_object_open(&obj, repo, id);
    	if (err)
    		return err;
    	if (got_object_get_type(obj) != GOT_OBJ_TYPE_TREE) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	err = got_object_tree_open(tree, repo, obj);
    done:
    	got_object_close(obj);
    	return err;
    }
    
    void
    got_object_tree_close(struct got_tree_object *tree)
    {
    	struct got_tree_entry *te;
    
    	if (tree->refcnt > 0) {
    		tree->refcnt--;
    		if (tree->refcnt > 0)
    			return;
    	}
    
    	while (!SIMPLEQ_EMPTY(&tree->entries.head)) {
    		te = SIMPLEQ_FIRST(&tree->entries.head);
    		SIMPLEQ_REMOVE_HEAD(&tree->entries.head, entry);
    		tree_entry_close(te);
    	}
    
    	free(tree);
    }
    
    const struct got_tree_entries *
    got_object_tree_get_entries(struct got_tree_object *tree)
    {
    	return &tree->entries;
    }
    
    static const struct got_error *
    read_blob_object_privsep_child(int outfd, int infd, int imsg_fds[2])
    {
    	const struct got_error *err = NULL;
    	struct imsgbuf ibuf;
    	int status = 0;
    	size_t size;
    	FILE *infile = NULL;
    
    	setproctitle("read blob 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;
    	}
    
    	infile = fdopen(infd, "rb");
    	if (infile == NULL) {
    		err = got_error_from_errno();
    		close(infd);
    		goto done;
    	}
    	err = got_inflate_to_fd(&size, infile, outfd);
    	fclose(infile);
    	if (err)
    		goto done;
    
    	err = got_privsep_send_blob(&ibuf, size);
    done:
    	if (err) {
    		got_privsep_send_error(&ibuf, err);
    		status = 1;
    	}
    	close(outfd);
    	imsg_clear(&ibuf);
    	close(imsg_fds[1]);
    	_exit(status);
    }
    
    static const struct got_error *
    read_blob_object_privsep(size_t *size, int outfd, int infd)
    {
    	struct imsgbuf parent_ibuf;
    	int imsg_fds[2];
    	const struct got_error *err = NULL, *err_child = NULL;
    	pid_t pid;
    
    	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_blob_object_privsep_child(outfd, infd, imsg_fds);
    		/* not reached */
    	}
    
    	close(imsg_fds[1]);
    	imsg_init(&parent_ibuf, imsg_fds[0]);
    	err = got_privsep_recv_blob(size, &parent_ibuf);
    	imsg_clear(&parent_ibuf);
    	err_child = wait_for_child(pid);
    	close(imsg_fds[0]);
    	if (lseek(outfd, SEEK_SET, 0) == -1)
    		err = got_error_from_errno();
    	return err ? err : err_child;
    }
    
    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();
    
    	(*blob)->read_buf = malloc(blocksize);
    	if ((*blob)->read_buf == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	if (obj->flags & GOT_OBJ_FLAG_PACKED) {
    		err = got_packfile_extract_object(&((*blob)->f), obj, repo);
    		if (err)
    			goto done;
    	} else {
    		int infd, outfd;
    		size_t size;
    		struct stat sb;
    
    		err = open_loose_object(&infd, obj, repo);
    		if (err)
    			goto done;
    
    
    		outfd = got_opentempfd();
    		if (outfd == -1) {
    			err = got_error_from_errno();
    			close(infd);
    			goto done;
    		}
    
    		err = read_blob_object_privsep(&size, outfd, infd);
    		close(infd);
    		if (err)
    			goto done;
    
    		if (size != obj->hdrlen + obj->size) {
    			err = got_error(GOT_ERR_PRIVSEP_LEN);
    			close(outfd);
    			goto done;
    		}
    
    		if (fstat(outfd, &sb) == -1) {
    			err = got_error_from_errno();
    			close(outfd);
    			goto done;
    		}
    
    		if (sb.st_size != size) {
    			err = got_error(GOT_ERR_PRIVSEP_LEN);
    			close(outfd);
    			goto done;
    		}
    
    		(*blob)->f = fdopen(outfd, "rb");
    		if ((*blob)->f == NULL) {
    			err = got_error_from_errno();
    			close(outfd);
    			goto done;
    		}
    	}
    
    	(*blob)->hdrlen = obj->hdrlen;
    	(*blob)->blocksize = blocksize;
    	memcpy(&(*blob)->id.sha1, obj->id.sha1, SHA1_DIGEST_LENGTH);
    
    done:
    	if (err && *blob) {
    		if ((*blob)->f)
    			fclose((*blob)->f);
    		free((*blob)->read_buf);
    		free(*blob);
    		*blob = NULL;
    	}
    	return err;
    }
    
    const struct got_error *
    got_object_open_as_blob(struct got_blob_object **blob,
        struct got_repository *repo, struct got_object_id *id,
        size_t blocksize)
    {
    	const struct got_error *err;
    	struct got_object *obj;
    
    	*blob = NULL;
    
    	err = got_object_open(&obj, repo, id);
    	if (err)
    		return err;
    	if (got_object_get_type(obj) != GOT_OBJ_TYPE_BLOB) {
    		err = got_error(GOT_ERR_OBJ_TYPE);
    		goto done;
    	}
    
    	err = got_object_blob_open(blob, repo, obj, blocksize);
    done:
    	got_object_close(obj);
    	return err;
    }
    
    void
    got_object_blob_close(struct got_blob_object *blob)
    {
    	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;
    
    	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;
    }
    
    const struct got_error *
    got_object_blob_dump_to_file(size_t *total_len, size_t *nlines,
        FILE *outfile, struct got_blob_object *blob)
    {
    	const struct got_error *err = NULL;
    	size_t len, hdrlen;
    	const uint8_t *buf;
    	int i;
    
    	if (total_len)
    		*total_len = 0;
    	if (nlines)
    		*nlines = 0;
    
    	hdrlen = got_object_blob_get_hdrlen(blob);
    	do {
    		err = got_object_blob_read_block(&len, blob);
    		if (err)
    			return err;
    		if (len == 0)
    			break;
    		if (total_len)
    			*total_len += len;
    		buf = got_object_blob_get_read_buf(blob);
    		if (nlines) {
    			for (i = 0; i < len; i++) {
    				if (buf[i] == '\n')
    					(*nlines)++;
    			}
    		}
    		/* Skip blob object header first time around. */
    		fwrite(buf + hdrlen, len - hdrlen, 1, outfile);
    		hdrlen = 0;
    	} while (len != 0);
    
    	fflush(outfile);
    	rewind(outfile);
    
    	return NULL;
    }
    
    static struct got_tree_entry *
    find_entry_by_name(struct got_tree_object *tree, const char *name)
    {
    	struct got_tree_entry *te;
    
    	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
    		if (strcmp(te->name, name) == 0)
    			return te;
    	}
    	return NULL;
    }
    
    const struct got_error *
    got_object_open_by_path(struct got_object **obj, struct got_repository *repo,
        struct got_object_id *commit_id, const char *path)
    {
    	const struct got_error *err = NULL;
    	struct got_commit_object *commit = NULL;
    	struct got_tree_object *tree = NULL;
    	struct got_tree_entry *te = NULL;
    	char *seg, *s, *s0 = NULL;
    	size_t len = strlen(path);
    
    	*obj = NULL;
    
    	/* We are expecting an absolute in-repository path. */
    	if (path[0] != '/')
    		return got_error(GOT_ERR_NOT_ABSPATH);
    
    	err = got_object_open_as_commit(&commit, repo, commit_id);
    	if (err)
    		goto done;
    
    	/* Handle opening of root of commit's tree. */
    	if (path[1] == '\0') {
    		err = got_object_open(obj, repo, commit->tree_id);
    		if (err)
    			goto done;
    		return NULL;
    	}
    
    	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
    	if (err)
    		goto done;
    
    	s0 = strdup(path);
    	if (s0 == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    	err = got_canonpath(path, s0, len + 1);
    	if (err)
    		goto done;
    
    	s = s0;
    	s++; /* skip leading '/' */
    	len--;
    	seg = s;
    	while (len > 0) {
    		struct got_tree_object *next_tree;
    
    		if (*s != '/') {
    			s++;
    			len--;
    			if (*s)
    				continue;
    		}
    
    		/* end of path segment */
    		*s = '\0';
    
    		te = find_entry_by_name(tree, seg);
    		if (te == NULL) {
    			err = got_error(GOT_ERR_NO_OBJ);
    			goto done;
    		}
    
    		if (len == 0)
    			break;
    
    		seg = s + 1;
    		s++;
    		len--;
    		if (*s) {
    			err = got_object_open_as_tree(&next_tree, repo,
    			    te->id);
    			te = NULL;
    			if (err)
    				goto done;
    			got_object_tree_close(tree);
    			tree = next_tree;
    		}
    	}
    
    	if (te) {
    		err = got_object_open(obj, repo, te->id);
    		if (err)
    			goto done;
    	} else
    		err = got_error(GOT_ERR_NO_OBJ);
    done:
    	free(s0);
    	if (commit)
    		got_object_commit_close(commit);
    	if (tree)
    		got_object_tree_close(tree);
    	return err;
    }