Merge branch 'jk/snprintf-cleanups'

Code clean-up.

* jk/snprintf-cleanups:
  daemon: use an argv_array to exec children
  gc: replace local buffer with git_path
  transport-helper: replace checked snprintf with xsnprintf
  convert unchecked snprintf into xsnprintf
  combine-diff: replace malloc/snprintf with xstrfmt
  replace unchecked snprintf calls with heap buffers
  receive-pack: print --pack-header directly into argv array
  name-rev: replace static buffer with strbuf
  create_branch: use xstrfmt for reflog message
  create_branch: move msg setup closer to point of use
  avoid using mksnpath for refs
  avoid using fixed PATH_MAX buffers for refs
  fetch: use heap buffer to format reflog
  tag: use strbuf to format tag header
  diff: avoid fixed-size buffer for patch-ids
  odb_mkstemp: use git_path_buf
  odb_mkstemp: write filename into strbuf
  do not check odb_mkstemp return value for errors

28 files changed, 239 insertions, 224 deletions

diff --git a/bisect.c b/bisect.c
index 30808cadf7..d12583eaac 100644
--- a/bisect.c
+++ b/bisect.c
@@ -200,6 +200,7 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
 {
 	struct commit_list *p;
 	struct commit_dist *array = xcalloc(nr, sizeof(*array));
+	struct strbuf buf = STRBUF_INIT;
 	int cnt, i;
 
 	for (p = list, cnt = 0; p; p = p->next) {
@@ -217,17 +218,18 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
 	}
 	QSORT(array, cnt, compare_commit_dist);
 	for (p = list, i = 0; i < cnt; i++) {
-		char buf[100]; /* enough for dist=%d */
 		struct object *obj = &(array[i].commit->object);
 
-		snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);
-		add_name_decoration(DECORATION_NONE, buf, obj);
+		strbuf_reset(&buf);
+		strbuf_addf(&buf, "dist=%d", array[i].distance);
+		add_name_decoration(DECORATION_NONE, buf.buf, obj);
 
 		p->item = array[i].commit;
 		p = p->next;
 	}
 	if (p)
 		p->next = NULL;
+	strbuf_release(&buf);
 	free(array);
 	return list;
 }
diff --git a/branch.c b/branch.c
index 5c12036b02..ad5a2299ba 100644
--- a/branch.c
+++ b/branch.c
@@ -234,7 +234,7 @@ void create_branch(const char *name, const char *start_name,
 {
 	struct commit *commit;
 	unsigned char sha1[20];
-	char *real_ref, msg[PATH_MAX + 20];
+	char *real_ref;
 	struct strbuf ref = STRBUF_INIT;
 	int forcing = 0;
 	int dont_change_ref = 0;
@@ -290,19 +290,18 @@ void create_branch(const char *name, const char *start_name,
 		die(_("Not a valid branch point: '%s'."), start_name);
 	hashcpy(sha1, commit->object.oid.hash);
 
-	if (forcing)
-		snprintf(msg, sizeof msg, "branch: Reset to %s",
-			 start_name);
-	else if (!dont_change_ref)
-		snprintf(msg, sizeof msg, "branch: Created from %s",
-			 start_name);
-
 	if (reflog)
 		log_all_ref_updates = LOG_REFS_NORMAL;
 
 	if (!dont_change_ref) {
 		struct ref_transaction *transaction;
 		struct strbuf err = STRBUF_INIT;
+		char *msg;
+
+		if (forcing)
+			msg = xstrfmt("branch: Reset to %s", start_name);
+		else
+			msg = xstrfmt("branch: Created from %s", start_name);
 
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
@@ -313,6 +312,7 @@ void create_branch(const char *name, const char *start_name,
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
+		free(msg);
 	}
 
 	if (real_ref && track)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 3ecc47bec0..bfa5419f33 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -908,11 +908,10 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
 	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
-	char src_ref[PATH_MAX];
-	snprintf(src_ref, PATH_MAX, "refs/heads/%s", name);
-	cb_data.src_ref = src_ref;
+	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	free(cb_data.src_ref);
 	if (cb_data.unique)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b5ad09d046..4ef7a08afc 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -421,7 +421,7 @@ static int s_update_ref(const char *action,
 			struct ref *ref,
 			int check_old)
 {
-	char msg[1024];
+	char *msg;
 	char *rla = getenv("GIT_REFLOG_ACTION");
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -431,7 +431,7 @@ static int s_update_ref(const char *action,
 		return 0;
 	if (!rla)
 		rla = default_rla.buf;
-	snprintf(msg, sizeof(msg), "%s: %s", rla, action);
+	msg = xstrfmt("%s: %s", rla, action);
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
@@ -449,11 +449,13 @@ static int s_update_ref(const char *action,
 
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
+	free(msg);
 	return 0;
 fail:
 	ref_transaction_free(transaction);
 	error("%s", err.buf);
 	strbuf_release(&err);
+	free(msg);
 	return df_conflict ? STORE_REF_ERROR_DF_CONFLICT
 			   : STORE_REF_ERROR_OTHER;
 }
diff --git a/builtin/gc.c b/builtin/gc.c
index c2c61a57bb..2daede7820 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -135,8 +135,6 @@ static int too_many_loose_objects(void)
 	 * distributed, we can check only one and get a reasonable
 	 * estimate.
 	 */
-	char path[PATH_MAX];
-	const char *objdir = get_object_directory();
 	DIR *dir;
 	struct dirent *ent;
 	int auto_threshold;
@@ -146,11 +144,7 @@ static int too_many_loose_objects(void)
 	if (gc_auto_threshold <= 0)
 		return 0;
 
-	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
-		warning(_("insanely long object directory %.*s"), 50, objdir);
-		return 0;
-	}
-	dir = opendir(path);
+	dir = opendir(git_path("objects/17"));
 	if (!dir)
 		return 0;
 
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 88d205f858..197c51912d 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -307,14 +307,15 @@ static const char *open_pack_file(const char *pack_name)
 	if (from_stdin) {
 		input_fd = 0;
 		if (!pack_name) {
-			static char tmp_file[PATH_MAX];
-			output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
+			struct strbuf tmp_file = STRBUF_INIT;
+			output_fd = odb_mkstemp(&tmp_file,
 						"pack/tmp_pack_XXXXXX");
-			pack_name = xstrdup(tmp_file);
-		} else
+			pack_name = strbuf_detach(&tmp_file, NULL);
+		} else {
 			output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
-		if (output_fd < 0)
-			die_errno(_("unable to create '%s'"), pack_name);
+			if (output_fd < 0)
+				die_errno(_("unable to create '%s'"), pack_name);
+		}
 		nothread_data.pack_fd = output_fd;
 	} else {
 		input_fd = open(pack_name, O_RDONLY);
@@ -1442,10 +1443,11 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
 	if (!from_stdin) {
 		printf("%s\n", sha1_to_hex(sha1));
 	} else {
-		char buf[48];
-		int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
-				   report, sha1_to_hex(sha1));
-		write_or_die(1, buf, len);
+		struct strbuf buf = STRBUF_INIT;
+
+		strbuf_addf(&buf, "%s\t%s\n", report, sha1_to_hex(sha1));
+		write_or_die(1, buf.buf, buf.len);
+		strbuf_release(&buf);
 
 		/*
 		 * Let's just mimic git-unpack-objects here and write
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 66cdd45cc1..b2d7d5ce68 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -17,17 +17,19 @@ static const char * const ls_remote_usage[] = {
 static int tail_match(const char **pattern, const char *path)
 {
 	const char *p;
-	char pathbuf[PATH_MAX];
+	char *pathbuf;
 
 	if (!pattern)
 		return 1; /* no restriction */
 
-	if (snprintf(pathbuf, sizeof(pathbuf), "/%s", path) > sizeof(pathbuf))
-		return error("insanely long ref %.*s...", 20, path);
+	pathbuf = xstrfmt("/%s", path);
 	while ((p = *(pattern++)) != NULL) {
-		if (!wildmatch(p, pathbuf, 0, NULL))
+		if (!wildmatch(p, pathbuf, 0, NULL)) {
+			free(pathbuf);
 			return 1;
+		}
 	}
+	free(pathbuf);
 	return 0;
 }
 
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 8bdc3eaa6f..92a5d8a5d2 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -238,10 +238,9 @@ static const char *get_exact_ref_match(const struct object *o)
 	return NULL;
 }
 
-/* returns a static buffer */
-static const char *get_rev_name(const struct object *o)
+/* may return a constant string or use "buf" as scratch space */
+static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 {
-	static char buffer[1024];
 	struct rev_name *n;
 	struct commit *c;
 
@@ -258,10 +257,9 @@ static const char *get_rev_name(const struct object *o)
 		int len = strlen(n->tip_name);
 		if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
 			len -= 2;
-		snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
-				n->generation);
-
-		return buffer;
+		strbuf_reset(buf);
+		strbuf_addf(buf, "%.*s~%d", len, n->tip_name, n->generation);
+		return buf->buf;
 	}
 }
 
@@ -271,10 +269,11 @@ static void show_name(const struct object *obj,
 {
 	const char *name;
 	const struct object_id *oid = &obj->oid;
+	struct strbuf buf = STRBUF_INIT;
 
 	if (!name_only)
 		printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
-	name = get_rev_name(obj);
+	name = get_rev_name(obj, &buf);
 	if (name)
 		printf("%s\n", name);
 	else if (allow_undefined)
@@ -283,6 +282,7 @@ static void show_name(const struct object *obj,
 		printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
 	else
 		die("cannot describe '%s'", oid_to_hex(oid));
+	strbuf_release(&buf);
 }
 
 static char const * const name_rev_usage[] = {
@@ -294,6 +294,7 @@ static char const * const name_rev_usage[] = {
 
 static void name_rev_line(char *p, struct name_ref_data *data)
 {
+	struct strbuf buf = STRBUF_INIT;
 	int forty = 0;
 	char *p_start;
 	for (p_start = p; *p; p++) {
@@ -314,7 +315,7 @@ static void name_rev_line(char *p, struct name_ref_data *data)
 				struct object *o =
 					lookup_object(sha1);
 				if (o)
-					name = get_rev_name(o);
+					name = get_rev_name(o, &buf);
 			}
 			*(p+1) = c;
 
@@ -332,6 +333,8 @@ static void name_rev_line(char *p, struct name_ref_data *data)
 	/* flush */
 	if (p_start != p)
 		fwrite(p_start, p - p_start, 1, stdout);
+
+	strbuf_release(&buf);
 }
 
 int cmd_name_rev(int argc, const char **argv, const char *prefix)
diff --git a/builtin/notes.c b/builtin/notes.c
index 0513f7455d..7b891471c4 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -554,7 +554,7 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 	struct notes_tree *t;
 	unsigned char object[20], new_note[20];
 	const unsigned char *note;
-	char logmsg[100];
+	char *logmsg;
 	const char * const *usage;
 	struct note_data d = { 0, 0, NULL, STRBUF_INIT };
 	struct option options[] = {
@@ -618,17 +618,16 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 		write_note_data(&d, new_note);
 		if (add_note(t, object, new_note, combine_notes_overwrite))
 			die("BUG: combine_notes_overwrite failed");
-		snprintf(logmsg, sizeof(logmsg), "Notes added by 'git notes %s'",
-			argv[0]);
+		logmsg = xstrfmt("Notes added by 'git notes %s'", argv[0]);
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
 			sha1_to_hex(object));
 		remove_note(t, object);
-		snprintf(logmsg, sizeof(logmsg), "Notes removed by 'git notes %s'",
-			argv[0]);
+		logmsg = xstrfmt("Notes removed by 'git notes %s'", argv[0]);
 	}
 	commit_notes(t, logmsg);
 
+	free(logmsg);
 	free_note_data(&d);
 	free_notes(t);
 	return 0;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index aca9c33d8d..7020278081 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1634,12 +1634,17 @@ static const char *parse_pack_header(struct pack_header *hdr)
 
 static const char *pack_lockfile;
 
+static void push_header_arg(struct argv_array *args, struct pack_header *hdr)
+{
+	argv_array_pushf(args, "--pack_header=%"PRIu32",%"PRIu32,
+			ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
+}
+
 static const char *unpack(int err_fd, struct shallow_info *si)
 {
 	struct pack_header hdr;
 	const char *hdr_err;
 	int status;
-	char hdr_arg[38];
 	struct child_process child = CHILD_PROCESS_INIT;
 	int fsck_objects = (receive_fsck_objects >= 0
 			    ? receive_fsck_objects
@@ -1653,9 +1658,6 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 			close(err_fd);
 		return hdr_err;
 	}
-	snprintf(hdr_arg, sizeof(hdr_arg),
-			"--pack_header=%"PRIu32",%"PRIu32,
-			ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 
 	if (si->nr_ours || si->nr_theirs) {
 		alt_shallow_file = setup_temporary_shallow(si->shallow);
@@ -1679,7 +1681,8 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 	tmp_objdir_add_as_alternate(tmp_objdir);
 
 	if (ntohl(hdr.hdr_entries) < unpack_limit) {
-		argv_array_pushl(&child.args, "unpack-objects", hdr_arg, NULL);
+		argv_array_push(&child.args, "unpack-objects");
+		push_header_arg(&child.args, &hdr);
 		if (quiet)
 			argv_array_push(&child.args, "-q");
 		if (fsck_objects)
@@ -1697,8 +1700,8 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 	} else {
 		char hostname[256];
 
-		argv_array_pushl(&child.args, "index-pack",
-				 "--stdin", hdr_arg, NULL);
+		argv_array_pushl(&child.args, "index-pack", "--stdin", NULL);
+		push_header_arg(&child.args, &hdr);
 
 		if (gethostname(hostname, sizeof(hostname)))
 			xsnprintf(hostname, sizeof(hostname), "localhost");
diff --git a/builtin/replace.c b/builtin/replace.c
index f83e7b8fc1..065515baba 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -93,26 +93,31 @@ typedef int (*each_replace_name_fn)(const char *name, const char *ref,
 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 {
 	const char **p, *full_hex;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
+	size_t base_len;
 	int had_error = 0;
 	struct object_id oid;
 
+	strbuf_addstr(&ref, git_replace_ref_base);
+	base_len = ref.len;
+
 	for (p = argv; *p; p++) {
 		if (get_oid(*p, &oid)) {
 			error("Failed to resolve '%s' as a valid ref.", *p);
 			had_error = 1;
 			continue;
 		}
-		full_hex = oid_to_hex(&oid);
-		snprintf(ref, sizeof(ref), "%s%s", git_replace_ref_base, full_hex);
-		/* read_ref() may reuse the buffer */
-		full_hex = ref + strlen(git_replace_ref_base);
-		if (read_ref(ref, oid.hash)) {
+
+		strbuf_setlen(&ref, base_len);
+		strbuf_addstr(&ref, oid_to_hex(&oid));
+		full_hex = ref.buf + base_len;
+
+		if (read_ref(ref.buf, oid.hash)) {
 			error("replace ref '%s' not found.", full_hex);
 			had_error = 1;
 			continue;
 		}
-		if (fn(full_hex, ref, &oid))
+		if (fn(full_hex, ref.buf, &oid))
 			had_error = 1;
 	}
 	return had_error;
@@ -129,21 +134,18 @@ static int delete_replace_ref(const char *name, const char *ref,
 
 static void check_ref_valid(struct object_id *object,
 			    struct object_id *prev,
-			    char *ref,
-			    int ref_size,
+			    struct strbuf *ref,
 			    int force)
 {
-	if (snprintf(ref, ref_size,
-		     "%s%s", git_replace_ref_base,
-		     oid_to_hex(object)) > ref_size - 1)
-		die("replace ref name too long: %.*s...", 50, ref);
-	if (check_refname_format(ref, 0))
-		die("'%s' is not a valid ref name.", ref);
-
-	if (read_ref(ref, prev->hash))
+	strbuf_reset(ref);
+	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
+	if (check_refname_format(ref->buf, 0))
+		die("'%s' is not a valid ref name.", ref->buf);
+
+	if (read_ref(ref->buf, prev->hash))
 		oidclr(prev);
 	else if (!force)
-		die("replace ref '%s' already exists", ref);
+		die("replace ref '%s' already exists", ref->buf);
 }
 
 static int replace_object_oid(const char *object_ref,
@@ -154,7 +156,7 @@ static int replace_object_oid(const char *object_ref,
 {
 	struct object_id prev;
 	enum object_type obj_type, repl_type;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
@@ -167,16 +169,17 @@ static int replace_object_oid(const char *object_ref,
 		    object_ref, typename(obj_type),
 		    replace_ref, typename(repl_type));
 
-	check_ref_valid(object, &prev, ref, sizeof(ref), force);
+	check_ref_valid(object, &prev, &ref, force);
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref, repl->hash, prev.hash,
+	    ref_transaction_update(transaction, ref.buf, repl->hash, prev.hash,
 				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 
 	ref_transaction_free(transaction);
+	strbuf_release(&ref);
 	return 0;
 }
 
@@ -280,7 +283,7 @@ static int edit_and_replace(const char *object_ref, int force, int raw)
 	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 	enum object_type type;
 	struct object_id old, new, prev;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 
 	if (get_oid(object_ref, &old) < 0)
 		die("Not a valid object name: '%s'", object_ref);
@@ -289,7 +292,8 @@ static int edit_and_replace(const char *object_ref, int force, int raw)
 	if (type < 0)
 		die("unable to get object type for %s", oid_to_hex(&old));
 
-	check_ref_valid(&old, &prev, ref, sizeof(ref), force);
+	check_ref_valid(&old, &prev, &ref, force);
+	strbuf_release(&ref);
 
 	export_object(&old, type, raw, tmpfile);
 	if (launch_editor(tmpfile, NULL, NULL) < 0)
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 9e53a1a7ca..f54d7b5028 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -213,13 +213,14 @@ static int show_abbrev(const unsigned char *sha1, void *cb_data)
 
 static void show_datestring(const char *flag, const char *datestr)
 {
-	static char buffer[100];
+	char *buffer;
 
 	/* date handling requires both flags and revs */
 	if ((filter & (DO_FLAGS | DO_REVS)) != (DO_FLAGS | DO_REVS))
 		return;
-	snprintf(buffer, sizeof(buffer), "%s%lu", flag, approxidate(datestr));
+	buffer = xstrfmt("%s%lu", flag, approxidate(datestr));
 	show(buffer);
+	free(buffer);
 }
 
 static int show_file(const char *arg, int output_prefix)
diff --git a/builtin/tag.c b/builtin/tag.c
index dbc6f5b74b..222404522f 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -72,25 +72,22 @@ static int for_each_tag_name(const char **argv, each_tag_name_fn fn,
 			     const void *cb_data)
 {
 	const char **p;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 	int had_error = 0;
 	unsigned char sha1[20];
 
 	for (p = argv; *p; p++) {
-		if (snprintf(ref, sizeof(ref), "refs/tags/%s", *p)
-					>= sizeof(ref)) {
-			error(_("tag name too long: %.*s..."), 50, *p);
-			had_error = 1;
-			continue;
-		}
-		if (read_ref(ref, sha1)) {
+		strbuf_reset(&ref);
+		strbuf_addf(&ref, "refs/tags/%s", *p);
+		if (read_ref(ref.buf, sha1)) {
 			error(_("tag '%s' not found."), *p);
 			had_error = 1;
 			continue;
 		}
-		if (fn(*p, ref, sha1, cb_data))
+		if (fn(*p, ref.buf, sha1, cb_data))
 			had_error = 1;
 	}
+	strbuf_release(&ref);
 	return had_error;
 }
 
@@ -231,26 +228,22 @@ static void create_tag(const unsigned char *object, const char *tag,
 		       unsigned char *prev, unsigned char *result)
 {
 	enum object_type type;
-	char header_buf[1024];
-	int header_len;
+	struct strbuf header = STRBUF_INIT;
 	char *path = NULL;
 
 	type = sha1_object_info(object, NULL);
 	if (type <= OBJ_NONE)
 	    die(_("bad object type."));
 
-	header_len = snprintf(header_buf, sizeof(header_buf),
-			  "object %s\n"
-			  "type %s\n"
-			  "tag %s\n"
-			  "tagger %s\n\n",
-			  sha1_to_hex(object),
-			  typename(type),
-			  tag,
-			  git_committer_info(IDENT_STRICT));
-
-	if (header_len > sizeof(header_buf) - 1)
-		die(_("tag header too big."));
+	strbuf_addf(&header,
+		    "object %s\n"
+		    "type %s\n"
+		    "tag %s\n"
+		    "tagger %s\n\n",
+		    sha1_to_hex(object),
+		    typename(type),
+		    tag,
+		    git_committer_info(IDENT_STRICT));
 
 	if (!opt->message_given) {
 		int fd;
@@ -288,7 +281,8 @@ static void create_tag(const unsigned char *object, const char *tag,
 	if (!opt->message_given && !buf->len)
 		die(_("no tag message?"));
 
-	strbuf_insert(buf, 0, header_buf, header_len);
+	strbuf_insert(buf, 0, header.buf, header.len);
+	strbuf_release(&header);
 
 	if (build_tag_object(buf, opt->sign, result) < 0) {
 		if (path)
diff --git a/cache.h b/cache.h
index 5c8078291c..556468c25b 100644
--- a/cache.h
+++ b/cache.h
@@ -1675,9 +1675,12 @@ extern struct packed_git *find_sha1_pack(const unsigned char *sha1,
 extern void pack_report(void);
 
 /*
- * Create a temporary file rooted in the object database directory.
+ * Create a temporary file rooted in the object database directory, or
+ * die on failure. The filename is taken from "pattern", which should have the
+ * usual "XXXXXX" trailer, and the resulting filename is written into the
+ * "template" buffer. Returns the open descriptor.
  */
-extern int odb_mkstemp(char *template, size_t limit, const char *pattern);
+extern int odb_mkstemp(struct strbuf *template, const char *pattern);
 
 /*
  * Generate the filename to be used for a pack file with checksum "sha1" and
diff --git a/combine-diff.c b/combine-diff.c
index 59501db99a..d3560573ac 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -292,9 +292,10 @@ static char *grab_blob(const struct object_id *oid, unsigned int mode,
 	enum object_type type;
 
 	if (S_ISGITLINK(mode)) {
-		blob = xmalloc(100);
-		*size = snprintf(blob, 100,
-				 "Subproject commit %s\n", oid_to_hex(oid));
+		struct strbuf buf = STRBUF_INIT;
+		strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
+		*size = buf.len;
+		blob = strbuf_detach(&buf, NULL);
 	} else if (is_null_oid(oid)) {
 		/* deleted blob */
 		*size = 0;
diff --git a/daemon.c b/daemon.c
index 473e6b6b63..f70d27b826 100644
--- a/daemon.c
+++ b/daemon.c
@@ -449,46 +449,42 @@ static void copy_to_log(int fd)
 	fclose(fp);
 }
 
-static int run_service_command(const char **argv)
+static int run_service_command(struct child_process *cld)
 {
-	struct child_process cld = CHILD_PROCESS_INIT;
-
-	cld.argv = argv;
-	cld.git_cmd = 1;
-	cld.err = -1;
-	if (start_command(&cld))
+	argv_array_push(&cld->args, ".");
+	cld->git_cmd = 1;
+	cld->err = -1;
+	if (start_command(cld))
 		return -1;
 
 	close(0);
 	close(1);
 
-	copy_to_log(cld.err);
+	copy_to_log(cld->err);
 
-	return finish_command(&cld);
+	return finish_command(cld);
 }
 
 static int upload_pack(void)
 {
-	/* Timeout as string */
-	char timeout_buf[64];
-	const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
-
-	argv[2] = timeout_buf;
-
-	snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_pushl(&cld.args, "upload-pack", "--strict", NULL);
+	argv_array_pushf(&cld.args, "--timeout=%u", timeout);
+	return run_service_command(&cld);
 }
 
 static int upload_archive(void)
 {
-	static const char *argv[] = { "upload-archive", ".", NULL };
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_push(&cld.args, "upload-archive");
+	return run_service_command(&cld);
 }
 
 static int receive_pack(void)
 {
-	static const char *argv[] = { "receive-pack", ".", NULL };
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_push(&cld.args, "receive-pack");
+	return run_service_command(&cld);
 }
 
 static struct daemon_service daemon_service[] = {
diff --git a/diff.c b/diff.c
index 58cb72d7e7..92d78e4596 100644
--- a/diff.c
+++ b/diff.c
@@ -4570,6 +4570,19 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 	data->patchlen += new_len;
 }
 
+static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
+{
+	git_SHA1_Update(ctx, str, strlen(str));
+}
+
+static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
+{
+	/* large enough for 2^32 in octal */
+	char buf[12];
+	int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
+	git_SHA1_Update(ctx, buf, len);
+}
+
 /* returns 0 upon success, and writes result into sha1 */
 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
 {
@@ -4577,7 +4590,6 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1,
 	int i;
 	git_SHA_CTX ctx;
 	struct patch_id_t data;
-	char buffer[PATH_MAX * 4 + 20];
 
 	git_SHA1_Init(&ctx);
 	memset(&data, 0, sizeof(struct patch_id_t));
@@ -4609,36 +4621,30 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1,
 
 		len1 = remove_space(p->one->path, strlen(p->one->path));
 		len2 = remove_space(p->two->path, strlen(p->two->path));
-		if (p->one->mode == 0)
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"newfilemode%06o"
-					"---/dev/null"
-					"+++b/%.*s",
-					len1, p->one->path,
-					len2, p->two->path,
-					p->two->mode,
-					len2, p->two->path);
-		else if (p->two->mode == 0)
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"deletedfilemode%06o"
-					"---a/%.*s"
-					"+++/dev/null",
-					len1, p->one->path,
-					len2, p->two->path,
-					p->one->mode,
-					len1, p->one->path);
-		else
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"---a/%.*s"
-					"+++b/%.*s",
-					len1, p->one->path,
-					len2, p->two->path,
-					len1, p->one->path,
-					len2, p->two->path);
-		git_SHA1_Update(&ctx, buffer, len1);
+		patch_id_add_string(&ctx, "diff--git");
+		patch_id_add_string(&ctx, "a/");
+		git_SHA1_Update(&ctx, p->one->path, len1);
+		patch_id_add_string(&ctx, "b/");
+		git_SHA1_Update(&ctx, p->two->path, len2);
+
+		if (p->one->mode == 0) {
+			patch_id_add_string(&ctx, "newfilemode");
+			patch_id_add_mode(&ctx, p->two->mode);
+			patch_id_add_string(&ctx, "---/dev/null");
+			patch_id_add_string(&ctx, "+++b/");
+			git_SHA1_Update(&ctx, p->two->path, len2);
+		} else if (p->two->mode == 0) {
+			patch_id_add_string(&ctx, "deletedfilemode");
+			patch_id_add_mode(&ctx, p->one->mode);
+			patch_id_add_string(&ctx, "---a/");
+			git_SHA1_Update(&ctx, p->one->path, len1);
+			patch_id_add_string(&ctx, "+++/dev/null");
+		} else {
+			patch_id_add_string(&ctx, "---a/");
+			git_SHA1_Update(&ctx, p->one->path, len1);
+			patch_id_add_string(&ctx, "+++b/");
+			git_SHA1_Update(&ctx, p->two->path, len2);
+		}
 
 		if (diff_header_only)
 			continue;
diff --git a/environment.c b/environment.c
index a17d96aa85..ff6e4f06e9 100644
--- a/environment.c
+++ b/environment.c
@@ -277,7 +277,7 @@ char *get_object_directory(void)
 	return git_object_dir;
 }
 
-int odb_mkstemp(char *template, size_t limit, const char *pattern)
+int odb_mkstemp(struct strbuf *template, const char *pattern)
 {
 	int fd;
 	/*
@@ -285,18 +285,16 @@ int odb_mkstemp(char *template, size_t limit, const char *pattern)
 	 * restrictive except to remove write permission.
 	 */
 	int mode = 0444;
-	snprintf(template, limit, "%s/%s",
-		 get_object_directory(), pattern);
-	fd = git_mkstemp_mode(template, mode);
+	git_path_buf(template, "objects/%s", pattern);
+	fd = git_mkstemp_mode(template->buf, mode);
 	if (0 <= fd)
 		return fd;
 
 	/* slow path */
 	/* some mkstemp implementations erase template on failure */
-	snprintf(template, limit, "%s/%s",
-		 get_object_directory(), pattern);
-	safe_create_leading_directories(template);
-	return xmkstemp_mode(template, mode);
+	git_path_buf(template, "objects/%s", pattern);
+	safe_create_leading_directories(template->buf);
+	return xmkstemp_mode(template->buf, mode);
 }
 
 int odb_pack_keep(const char *name)
diff --git a/fast-import.c b/fast-import.c
index f6f416f20a..1ea3a08609 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -890,14 +890,15 @@ static struct tree_content *dup_tree_content(struct tree_content *s)
 
 static void start_packfile(void)
 {
-	static char tmp_file[PATH_MAX];
+	struct strbuf tmp_file = STRBUF_INIT;
 	struct packed_git *p;
 	struct pack_header hdr;
 	int pack_fd;
 
-	pack_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
-			      "pack/tmp_pack_XXXXXX");
-	FLEX_ALLOC_STR(p, pack_name, tmp_file);
+	pack_fd = odb_mkstemp(&tmp_file, "pack/tmp_pack_XXXXXX");
+	FLEX_ALLOC_STR(p, pack_name, tmp_file.buf);
+	strbuf_release(&tmp_file);
+
 	p->pack_fd = pack_fd;
 	p->do_not_close = 1;
 	pack_file = sha1fd(pack_fd, p->pack_name);
diff --git a/grep.c b/grep.c
index 56ef0ecbff..47cee45067 100644
--- a/grep.c
+++ b/grep.c
@@ -1171,7 +1171,7 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 	}
 	if (opt->linenum) {
 		char buf[32];
-		snprintf(buf, sizeof(buf), "%d", lno);
+		xsnprintf(buf, sizeof(buf), "%d", lno);
 		output_color(opt, buf, strlen(buf), opt->color_lineno);
 		output_sep(opt, sign);
 	}
@@ -1653,7 +1653,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 				     opt->color_filename);
 			output_sep(opt, ':');
 		}
-		snprintf(buf, sizeof(buf), "%u\n", count);
+		xsnprintf(buf, sizeof(buf), "%u\n", count);
 		opt->output(opt, buf, strlen(buf));
 		return 1;
 	}
diff --git a/http.c b/http.c
index 96d84bbed3..8d94e2c63a 100644
--- a/http.c
+++ b/http.c
@@ -1366,9 +1366,9 @@ static int handle_curl_result(struct slot_results *results)
 		 * FAILONERROR it is lost, so we can give only the numeric
 		 * status code.
 		 */
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "The requested URL returned error: %ld",
-			 results->http_code);
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "The requested URL returned error: %ld",
+			  results->http_code);
 	}
 
 	if (results->curl_result == CURLE_OK) {
@@ -1410,8 +1410,8 @@ int run_one_slot(struct active_request_slot *slot,
 {
 	slot->results = results;
 	if (!start_active_slot(slot)) {
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "failed to start HTTP request");
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "failed to start HTTP request");
 		return HTTP_START_FAILED;
 	}
 
diff --git a/imap-send.c b/imap-send.c
index 5c7e27a894..857591660f 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -964,7 +964,7 @@ static struct imap_store *imap_open_store(struct imap_server_conf *srvc, char *f
 		int gai;
 		char portstr[6];
 
-		snprintf(portstr, sizeof(portstr), "%d", srvc->port);
+		xsnprintf(portstr, sizeof(portstr), "%d", srvc->port);
 
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_socktype = SOCK_STREAM;
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 9705596014..e313f4f2bc 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -508,18 +508,16 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
 			  const char *filename,
 			  uint16_t options)
 {
-	static char tmp_file[PATH_MAX];
 	static uint16_t default_version = 1;
 	static uint16_t flags = BITMAP_OPT_FULL_DAG;
+	struct strbuf tmp_file = STRBUF_INIT;
 	struct sha1file *f;
 
 	struct bitmap_disk_header header;
 
-	int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
+	int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
 
-	if (fd < 0)
-		die_errno("unable to create '%s'", tmp_file);
-	f = sha1fd(fd, tmp_file);
+	f = sha1fd(fd, tmp_file.buf);
 
 	memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 	header.version = htons(default_version);
@@ -539,9 +537,11 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
 
 	sha1close(f, NULL, CSUM_FSYNC);
 
-	if (adjust_shared_perm(tmp_file))
+	if (adjust_shared_perm(tmp_file.buf))
 		die_errno("unable to make temporary bitmap file readable");
 
-	if (rename(tmp_file, filename))
+	if (rename(tmp_file.buf, filename))
 		die_errno("unable to rename temporary bitmap file to '%s'", filename);
+
+	strbuf_release(&tmp_file);
 }
diff --git a/pack-write.c b/pack-write.c
index c057513f12..fa97b72559 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -71,15 +71,15 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 		f = sha1fd_check(index_name);
 	} else {
 		if (!index_name) {
-			static char tmp_file[PATH_MAX];
-			fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_idx_XXXXXX");
-			index_name = xstrdup(tmp_file);
+			struct strbuf tmp_file = STRBUF_INIT;
+			fd = odb_mkstemp(&tmp_file, "pack/tmp_idx_XXXXXX");
+			index_name = strbuf_detach(&tmp_file, NULL);
 		} else {
 			unlink(index_name);
 			fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
+			if (fd < 0)
+				die_errno("unable to create '%s'", index_name);
 		}
-		if (fd < 0)
-			die_errno("unable to create '%s'", index_name);
 		f = sha1fd(fd, index_name);
 	}
 
@@ -329,11 +329,11 @@ int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
 
 struct sha1file *create_tmp_packfile(char **pack_tmp_name)
 {
-	char tmpname[PATH_MAX];
+	struct strbuf tmpname = STRBUF_INIT;
 	int fd;
 
-	fd = odb_mkstemp(tmpname, sizeof(tmpname), "pack/tmp_pack_XXXXXX");
-	*pack_tmp_name = xstrdup(tmpname);
+	fd = odb_mkstemp(&tmpname, "pack/tmp_pack_XXXXXX");
+	*pack_tmp_name = strbuf_detach(&tmpname, NULL);
 	return sha1fd(fd, *pack_tmp_name);
 }
 
diff --git a/refs.c b/refs.c
index 0272e332cc..c2472184a7 100644
--- a/refs.c
+++ b/refs.c
@@ -429,29 +429,31 @@ int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 {
 	const char **p, *r;
 	int refs_found = 0;
+	struct strbuf fullref = STRBUF_INIT;
 
 	*ref = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
-		char fullref[PATH_MAX];
 		unsigned char sha1_from_ref[20];
 		unsigned char *this_result;
 		int flag;
 
 		this_result = refs_found ? sha1_from_ref : sha1;
-		mksnpath(fullref, sizeof(fullref), *p, len, str);
-		r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
+		strbuf_reset(&fullref);
+		strbuf_addf(&fullref, *p, len, str);
+		r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
 				       this_result, &flag);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
 			if (!warn_ambiguous_refs)
 				break;
-		} else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
-			warning("ignoring dangling symref %s.", fullref);
-		} else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
-			warning("ignoring broken ref %s.", fullref);
+		} else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
+			warning("ignoring dangling symref %s.", fullref.buf);
+		} else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
+			warning("ignoring broken ref %s.", fullref.buf);
 		}
 	}
+	strbuf_release(&fullref);
 	return refs_found;
 }
 
@@ -460,21 +462,22 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	char *last_branch = substitute_branch_name(&str, &len);
 	const char **p;
 	int logs_found = 0;
+	struct strbuf path = STRBUF_INIT;
 
 	*log = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
 		unsigned char hash[20];
-		char path[PATH_MAX];
 		const char *ref, *it;
 
-		mksnpath(path, sizeof(path), *p, len, str);
-		ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
+		strbuf_reset(&path);
+		strbuf_addf(&path, *p, len, str);
+		ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
 					 hash, NULL);
 		if (!ref)
 			continue;
-		if (reflog_exists(path))
-			it = path;
-		else if (strcmp(ref, path) && reflog_exists(ref))
+		if (reflog_exists(path.buf))
+			it = path.buf;
+		else if (strcmp(ref, path.buf) && reflog_exists(ref))
 			it = ref;
 		else
 			continue;
@@ -485,6 +488,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 		if (!warn_ambiguous_refs)
 			break;
 	}
+	strbuf_release(&path);
 	free(last_branch);
 	return logs_found;
 }
@@ -944,6 +948,7 @@ char *shorten_unambiguous_ref(const char *refname, int strict)
 	static char **scanf_fmts;
 	static int nr_rules;
 	char *short_name;
+	struct strbuf resolved_buf = STRBUF_INIT;
 
 	if (!nr_rules) {
 		/*
@@ -1002,7 +1007,6 @@ char *shorten_unambiguous_ref(const char *refname, int strict)
 		 */
 		for (j = 0; j < rules_to_fail; j++) {
 			const char *rule = ref_rev_parse_rules[j];
-			char refname[PATH_MAX];
 
 			/* skip matched rule */
 			if (i == j)
@@ -1013,9 +1017,10 @@ char *shorten_unambiguous_ref(const char *refname, int strict)
 			 * (with this previous rule) to a valid ref
 			 * read_ref() returns 0 on success
 			 */
-			mksnpath(refname, sizeof(refname),
-				 rule, short_name_len, short_name);
-			if (ref_exists(refname))
+			strbuf_reset(&resolved_buf);
+			strbuf_addf(&resolved_buf, rule,
+				    short_name_len, short_name);
+			if (ref_exists(resolved_buf.buf))
 				break;
 		}
 
@@ -1023,10 +1028,13 @@ char *shorten_unambiguous_ref(const char *refname, int strict)
 		 * short name is non-ambiguous if all previous rules
 		 * haven't resolved to a valid ref
 		 */
-		if (j == rules_to_fail)
+		if (j == rules_to_fail) {
+			strbuf_release(&resolved_buf);
 			return short_name;
+		}
 	}
 
+	strbuf_release(&resolved_buf);
 	free(short_name);
 	return xstrdup(refname);
 }
diff --git a/sha1_file.c b/sha1_file.c
index 71063890ff..43990dec73 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -3762,8 +3762,8 @@ static int for_each_file_in_obj_subdir(int subdir_nr,
 			char hex[GIT_SHA1_HEXSZ+1];
 			struct object_id oid;
 
-			snprintf(hex, sizeof(hex), "%02x%s",
-				 subdir_nr, de->d_name);
+			xsnprintf(hex, sizeof(hex), "%02x%s",
+				  subdir_nr, de->d_name);
 			if (!get_oid_hex(hex, &oid)) {
 				if (obj_cb) {
 					r = obj_cb(&oid, path->buf, data);
diff --git a/submodule.c b/submodule.c
index c52d6634c5..83b13b8ff5 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1436,7 +1436,7 @@ static int find_first_merges(struct object_array *result, const char *path,
 	memset(&rev_opts, 0, sizeof(rev_opts));
 
 	/* get all revisions that merge commit a */
-	snprintf(merged_revision, sizeof(merged_revision), "^%s",
+	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
 			oid_to_hex(&a->object.oid));
 	init_revisions(&revs, NULL);
 	rev_opts.submodule = path;
diff --git a/transport-helper.c b/transport-helper.c
index dc90a1fb76..36408046eb 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -347,14 +347,11 @@ static int set_helper_option(struct transport *transport,
 static void standard_options(struct transport *t)
 {
 	char buf[16];
-	int n;
 	int v = t->verbose;
 
 	set_helper_option(t, "progress", t->progress ? "true" : "false");
 
-	n = snprintf(buf, sizeof(buf), "%d", v + 1);
-	if (n >= sizeof(buf))
-		die("impossibly large verbosity value");
+	xsnprintf(buf, sizeof(buf), "%d", v + 1);
 	set_helper_option(t, "verbosity", buf);
 
 	switch (t->family) {