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thodg/got/lib/object_parse.c

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  • Author : Stefan Sperling
    Date : 2019-02-01 22:46:32
    Hash : e0e55b50
    Message : Support tags in Linux git repo which do not carry name of tagger.

  • lib/object_parse.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/syslimits.h>
    #include <sys/wait.h>
    
    #include <errno.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 <unistd.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_inflate.h"
    #include "got_lib_object.h"
    #include "got_lib_object_cache.h"
    #include "got_lib_pack.h"
    #include "got_lib_privsep.h"
    #include "got_lib_repository.h"
    
    #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_OBJ_TAG_TAG		"tag"
    
    #define GOT_COMMIT_TAG_TREE		"tree "
    #define GOT_COMMIT_TAG_PARENT		"parent "
    #define GOT_COMMIT_TAG_AUTHOR		"author "
    #define GOT_COMMIT_TAG_COMMITTER	"committer "
    
    #define GOT_TAG_TAG_OBJECT		"object "
    #define GOT_TAG_TAG_TYPE		"type "
    #define GOT_TAG_TAG_TAG			"tag "
    #define GOT_TAG_TAG_TAGGER		"tagger "
    
    int
    got_object_id_cmp(const struct got_object_id *id1,
        const struct got_object_id *id2)
    {
    	return memcmp(id1->sha1, id2->sha1, SHA1_DIGEST_LENGTH);
    }
    
    const struct got_error *
    got_object_qid_alloc_partial(struct got_object_qid **qid)
    {
    	const struct got_error *err = NULL;
    
    	*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();
    		got_object_qid_free(*qid);
    		*qid = NULL;
    		return err;
    	}
    
    	return NULL;
    }
    
    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;
    }
    
    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);
    }
    
    void
    got_object_qid_free(struct got_object_qid *qid)
    {
    	free(qid->id);
    	free(qid);
    }
    
    const struct got_error *
    got_object_parse_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,
    		GOT_OBJ_TAG_TAG,
    	};
    	const int obj_types[] = {
    		GOT_OBJ_TYPE_COMMIT,
    		GOT_OBJ_TYPE_TREE,
    		GOT_OBJ_TYPE_BLOB,
    		GOT_OBJ_TYPE_TAG,
    	};
    	int type = 0;
    	size_t size = 0, hdrlen = 0;
    	int i;
    	char *p = strchr(buf, '\0');
    
    	*obj = NULL;
    
    	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;
    }
    
    const struct got_error *
    got_object_read_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 nbuf = 1;
    
    	*obj = NULL;
    
    	buf = malloc(zbsize);
    	if (buf == NULL)
    		return got_error_from_errno();
    
    	err = got_inflate_init(&zb, buf, zbsize);
    	if (err)
    		return err;
    
    	totlen = 0;
    	do {
    		err = got_inflate_read_fd(&zb, fd, &outlen);
    		if (err)
    			goto done;
    		if (outlen == 0)
    			break;
    		totlen += outlen;
    		if (strchr(zb.outbuf, '\0') == NULL) {
    			char *newbuf;
    			nbuf++;
    			newbuf = recallocarray(buf, nbuf - 1, nbuf, zbsize);
    			if (newbuf == NULL) {
    				err = got_error_from_errno();
    				goto done;
    			}
    			buf = newbuf;
    			zb.outbuf = newbuf + totlen;
    			zb.outlen = (nbuf * zbsize) - totlen;
    		}
    	} while (strchr(zb.outbuf, '\0') == NULL);
    
    	err = got_object_parse_header(obj, buf, totlen);
    done:
    	free(buf);
    	got_inflate_end(&zb);
    	return err;
    }
    
    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 = malloc(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_object_qid *qid;
    
    	err = got_object_qid_alloc_partial(&qid);
    	if (err)
    		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(time_t *time, time_t *gmtoff, char *committer)
    {
    	const struct got_error *err = NULL;
    	const char *errstr;
    	char *space, *tzstr;
    
    	/* 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. */
    	*time -= *gmtoff;
    
    	/* Strip off parsed time information, leaving just author and email. */
    	*space = '\0';
    
    	return NULL;
    }
    
    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);
    		got_object_qid_free(qid);
    	}
    
    	free(commit->tree_id);
    	free(commit->author);
    	free(commit->committer);
    	free(commit->logmsg);
    	free(commit);
    }
    
    struct got_object_id *
    got_object_commit_get_tree_id(struct got_commit_object *commit)
    {
    	return commit->tree_id;
    }
    
    int
    got_object_commit_get_nparents(struct got_commit_object *commit)
    {
    	return commit->nparents;
    }
    
    const struct got_object_id_queue *
    got_object_commit_get_parent_ids(struct got_commit_object *commit)
    {
    	return &commit->parent_ids;
    }
    
    const char *
    got_object_commit_get_author(struct got_commit_object *commit)
    {
    	return commit->author;
    }
    
    time_t
    got_object_commit_get_author_time(struct got_commit_object *commit)
    {
    	return commit->author_time;
    }
    
    time_t got_object_commit_get_author_gmtoff(struct got_commit_object *commit)
    {
    	return commit->author_gmtoff;
    }
    
    const char *
    got_object_commit_get_committer(struct got_commit_object *commit)
    {
    	return commit->committer;
    }
    
    time_t
    got_object_commit_get_committer_time(struct got_commit_object *commit)
    {
    	return commit->committer_time;
    }
    
    time_t
    got_object_commit_get_committer_gmtoff(struct got_commit_object *commit)
    {
    	return commit->committer_gmtoff;
    }
    
    const char *
    got_object_commit_get_logmsg(struct got_commit_object *commit)
    {
    	return commit->logmsg;
    }
    
    const struct got_error *
    got_object_parse_commit(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)->author_time,
    		    &(*commit)->author_gmtoff, 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)->committer_time,
    		    &(*commit)->committer_gmtoff, 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;
    }
    
    void
    got_object_tree_entry_close(struct got_tree_entry *te)
    {
    	free(te->id);
    	free(te->name);
    	free(te);
    }
    
    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);
    		got_object_tree_entry_close(te);
    	}
    
    	free(tree);
    }
    
    struct got_tree_entry *
    got_alloc_tree_entry_partial(void)
    {
    	struct got_tree_entry *te;
    
    	te = malloc(sizeof(*te));
    	if (te == NULL)
    		return NULL;
    
    	te->id = malloc(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;
    	}
    	(*te)->mode = 0;
    	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 += *elen;
    	memcpy((*te)->id->sha1, buf, SHA1_DIGEST_LENGTH);
    	*elen += SHA1_DIGEST_LENGTH;
    done:
    	if (err) {
    		got_object_tree_entry_close(*te);
    		*te = NULL;
    	}
    	return err;
    }
    
    const struct got_error *
    got_object_parse_tree(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);
    		*tree = NULL;
    		return got_error(GOT_ERR_BAD_OBJ_DATA);
    	}
    
    	return NULL;
    }
    
    void
    got_object_tag_close(struct got_tag_object *tag)
    {
    	free(tag->tag);
    	free(tag->tagger);
    	free(tag->tagmsg);
    	free(tag);
    }
    
    const struct got_error *
    got_object_parse_tag(struct got_tag_object **tag, uint8_t *buf, size_t len)
    {
    	const struct got_error *err = NULL;
    	size_t remain = len;
    	char *s = buf;
    	size_t tlen;
    
    	*tag = calloc(1, sizeof(**tag));
    	if (*tag == NULL)
    		return got_error_from_errno();
    
    	tlen = strlen(GOT_TAG_TAG_OBJECT);
    	if (strncmp(s, GOT_TAG_TAG_OBJECT, 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((*tag)->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;
    	}
    
    	if (remain <= 0) {
    		err = got_error(GOT_ERR_BAD_OBJ_DATA);
    		goto done;
    	}
    
    	tlen = strlen(GOT_TAG_TAG_TYPE);
    	if (strncmp(s, GOT_TAG_TAG_TYPE, tlen) == 0) {
    		remain -= tlen;
    		if (remain <= 0) {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    		s += tlen;
    		if (strncmp(s, GOT_OBJ_TAG_COMMIT,
    		    strlen(GOT_OBJ_TAG_COMMIT)) == 0) {
    			(*tag)->obj_type = GOT_OBJ_TYPE_COMMIT;
    			tlen = strlen(GOT_OBJ_TAG_COMMIT);
    			s += tlen;
    			remain -= tlen;
    		} else if (strncmp(s, GOT_OBJ_TAG_TREE,
    		    strlen(GOT_OBJ_TAG_TREE)) == 0) {
    			(*tag)->obj_type = GOT_OBJ_TYPE_TREE;
    			tlen = strlen(GOT_OBJ_TAG_TREE);
    			s += tlen;
    			remain -= tlen;
    		} else if (strncmp(s, GOT_OBJ_TAG_BLOB,
    		    strlen(GOT_OBJ_TAG_BLOB)) == 0) {
    			(*tag)->obj_type = GOT_OBJ_TYPE_BLOB;
    			tlen = strlen(GOT_OBJ_TAG_BLOB);
    			s += tlen;
    			remain -= tlen;
    		} else if (strncmp(s, GOT_OBJ_TAG_TAG,
    		    strlen(GOT_OBJ_TAG_TAG)) == 0) {
    			(*tag)->obj_type = GOT_OBJ_TYPE_TAG;
    			tlen = strlen(GOT_OBJ_TAG_TAG);
    			s += tlen;
    			remain -= tlen;
    		} else {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    
    		if (remain <= 0 || *s != '\n') {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    		s++;
    		remain--;
    		if (remain <= 0) {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    	} else {
    		err = got_error(GOT_ERR_BAD_OBJ_DATA);
    		goto done;
    	}
    
    	tlen = strlen(GOT_TAG_TAG_TAG);
    	if (strncmp(s, GOT_TAG_TAG_TAG, 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);
    		(*tag)->tag = strndup(s, slen);
    		if ((*tag)->tag == NULL) {
    			err = got_error_from_errno();
    			goto done;
    		}
    		s += slen + 1;
    		remain -= slen + 1;
    		if (remain <= 0) {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    	} else {
    		err = got_error(GOT_ERR_BAD_OBJ_DATA);
    		goto done;
    	}
    
    	tlen = strlen(GOT_TAG_TAG_TAGGER);
    	if (strncmp(s, GOT_TAG_TAG_TAGGER, 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(&(*tag)->tagger_time,
    		    &(*tag)->tagger_gmtoff, s);
    		if (err)
    			goto done;
    		(*tag)->tagger = strdup(s);
    		if ((*tag)->tagger == NULL) {
    			err = got_error_from_errno();
    			goto done;
    		}
    		s += slen + 1;
    		remain -= slen + 1;
    		if (remain <= 0) {
    			err = got_error(GOT_ERR_BAD_OBJ_DATA);
    			goto done;
    		}
    	} else {
    		/* Some old tags in the Linux git repo have no tagger. */
    		(*tag)->tagger = strdup("");
    		if ((*tag)->tagger == NULL) {
    			err = got_error_from_errno();
    			goto done;
    		}
    	}
    
    	(*tag)->tagmsg = strndup(s, remain);
    	if ((*tag)->tagmsg == NULL) {
    		err = got_error_from_errno();
    		goto done;
    	}
    done:
    	if (err) {
    		got_object_tag_close(*tag);
    		*tag = NULL;
    	}
    	return err;
    }
    
    const struct got_error *
    got_read_file_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;
    }