Merge branch 'jk/tighten-alloc' into maint

* jk/tighten-alloc: (23 commits)
  compat/mingw: brown paper bag fix for 50a6c8e
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  ...

91 files changed, 441 insertions, 482 deletions

diff --git a/Documentation/technical/api-argv-array.txt b/Documentation/technical/api-argv-array.txt
index 8076172a08..cfc063018c 100644
--- a/Documentation/technical/api-argv-array.txt
+++ b/Documentation/technical/api-argv-array.txt
@@ -56,3 +56,10 @@ Functions
 `argv_array_clear`::
 	Free all memory associated with the array and return it to the
 	initial, empty state.
+
+`argv_array_detach`::
+	Disconnect the `argv` member from the `argv_array` struct and
+	return it. The caller is responsible for freeing the memory used
+	by the array, and by the strings it references. After detaching,
+	the `argv_array` is in a reinitialized state and can be pushed
+	into again.
diff --git a/alias.c b/alias.c
index a11229db9e..3b90397a99 100644
--- a/alias.c
+++ b/alias.c
@@ -23,7 +23,7 @@ int split_cmdline(char *cmdline, const char ***argv)
 	int src, dst, count = 0, size = 16;
 	char quoted = 0;
 
-	*argv = xmalloc(sizeof(**argv) * size);
+	ALLOC_ARRAY(*argv, size);
 
 	/* split alias_string */
 	(*argv)[count++] = cmdline;
diff --git a/archive.c b/archive.c
index 0687afae43..5d735ae603 100644
--- a/archive.c
+++ b/archive.c
@@ -171,8 +171,8 @@ static void queue_directory(const unsigned char *sha1,
 		unsigned mode, int stage, struct archiver_context *c)
 {
 	struct directory *d;
-	size_t len = base->len + 1 + strlen(filename) + 1;
-	d = xmalloc(sizeof(*d) + len);
+	size_t len = st_add4(base->len, 1, strlen(filename), 1);
+	d = xmalloc(st_add(sizeof(*d), len));
 	d->up	   = c->bottom;
 	d->baselen = base->len;
 	d->mode	   = mode;
diff --git a/argv-array.c b/argv-array.c
index eaed47712b..5d370fa336 100644
--- a/argv-array.c
+++ b/argv-array.c
@@ -74,3 +74,14 @@ void argv_array_clear(struct argv_array *array)
 	}
 	argv_array_init(array);
 }
+
+const char **argv_array_detach(struct argv_array *array)
+{
+	if (array->argv == empty_argv)
+		return xcalloc(1, sizeof(const char *));
+	else {
+		const char **ret = array->argv;
+		argv_array_init(array);
+		return ret;
+	}
+}
diff --git a/argv-array.h b/argv-array.h
index a2fa0aa606..29056e49a1 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -20,5 +20,6 @@ void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pushv(struct argv_array *, const char **);
 void argv_array_pop(struct argv_array *);
 void argv_array_clear(struct argv_array *);
+const char **argv_array_detach(struct argv_array *);
 
 #endif /* ARGV_ARRAY_H */
diff --git a/attr.c b/attr.c
index 086c08dcfa..6537a433da 100644
--- a/attr.c
+++ b/attr.c
@@ -93,9 +93,7 @@ static struct git_attr *git_attr_internal(const char *name, int len)
 	if (invalid_attr_name(name, len))
 		return NULL;
 
-	a = xmalloc(sizeof(*a) + len + 1);
-	memcpy(a->name, name, len);
-	a->name[len] = 0;
+	FLEX_ALLOC_MEM(a, name, name, len);
 	a->h = hval;
 	a->next = git_attr_hash[pos];
 	a->attr_nr = attr_nr++;
@@ -799,7 +797,7 @@ int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
 			++count;
 	}
 	*num = count;
-	*check = xmalloc(sizeof(**check) * count);
+	ALLOC_ARRAY(*check, count);
 	j = 0;
 	for (i = 0; i < attr_nr; i++) {
 		const char *value = check_all_attr[i].value;
diff --git a/bisect.c b/bisect.c
index 42aa7aa6aa..6d0793b9fc 100644
--- a/bisect.c
+++ b/bisect.c
@@ -708,10 +708,10 @@ static struct commit *get_commit_reference(const unsigned char *sha1)
 
 static struct commit **get_bad_and_good_commits(int *rev_nr)
 {
-	int len = 1 + good_revs.nr;
-	struct commit **rev = xmalloc(len * sizeof(*rev));
+	struct commit **rev;
 	int i, n = 0;
 
+	ALLOC_ARRAY(rev, 1 + good_revs.nr);
 	rev[n++] = get_commit_reference(current_bad_oid->hash);
 	for (i = 0; i < good_revs.nr; i++)
 		rev[n++] = get_commit_reference(good_revs.sha1[i]);
diff --git a/builtin/apply.c b/builtin/apply.c
index deb1364fa8..0db6d14cc2 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -2632,7 +2632,7 @@ static void update_image(struct image *img,
 	insert_count = postimage->len;
 
 	/* Adjust the contents */
-	result = xmalloc(img->len + insert_count - remove_count + 1);
+	result = xmalloc(st_add3(st_sub(img->len, remove_count), insert_count, 1));
 	memcpy(result, img->buf, applied_at);
 	memcpy(result + applied_at, postimage->buf, postimage->len);
 	memcpy(result + applied_at + postimage->len,
diff --git a/builtin/blame.c b/builtin/blame.c
index 5265f79edc..0b4f0bbb53 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -459,13 +459,11 @@ static void queue_blames(struct scoreboard *sb, struct origin *porigin,
 static struct origin *make_origin(struct commit *commit, const char *path)
 {
 	struct origin *o;
-	size_t pathlen = strlen(path) + 1;
-	o = xcalloc(1, sizeof(*o) + pathlen);
+	FLEX_ALLOC_STR(o, path, path);
 	o->commit = commit;
 	o->refcnt = 1;
 	o->next = commit->util;
 	commit->util = o;
-	memcpy(o->path, path, pathlen); /* includes NUL */
 	return o;
 }
 
@@ -2042,7 +2040,8 @@ static int prepare_lines(struct scoreboard *sb)
 	for (p = buf; p < end; p = get_next_line(p, end))
 		num++;
 
-	sb->lineno = lineno = xmalloc(sizeof(*sb->lineno) * (num + 1));
+	ALLOC_ARRAY(sb->lineno, num + 1);
+	lineno = sb->lineno;
 
 	for (p = buf; p < end; p = get_next_line(p, end))
 		*lineno++ = p - buf;
diff --git a/builtin/check-ref-format.c b/builtin/check-ref-format.c
index fd915d5984..eac499450f 100644
--- a/builtin/check-ref-format.c
+++ b/builtin/check-ref-format.c
@@ -20,7 +20,7 @@ static const char builtin_check_ref_format_usage[] =
  */
 static char *collapse_slashes(const char *refname)
 {
-	char *ret = xmalloc(strlen(refname) + 1);
+	char *ret = xmallocz(strlen(refname));
 	char ch;
 	char prev = '/';
 	char *cp = ret;
diff --git a/builtin/clean.c b/builtin/clean.c
index 919157bc2f..fb1824ce95 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -543,7 +543,7 @@ static int *list_and_choose(struct menu_opts *opts, struct menu_stuff *stuff)
 	int eof = 0;
 	int i;
 
-	chosen = xmalloc(sizeof(int) * stuff->nr);
+	ALLOC_ARRAY(chosen, stuff->nr);
 	/* set chosen as uninitialized */
 	for (i = 0; i < stuff->nr; i++)
 		chosen[i] = -1;
@@ -615,7 +615,7 @@ static int *list_and_choose(struct menu_opts *opts, struct menu_stuff *stuff)
 				nr += chosen[i];
 		}
 
-		result = xcalloc(nr + 1, sizeof(int));
+		result = xcalloc(st_add(nr, 1), sizeof(int));
 		for (i = 0; i < stuff->nr && j < nr; i++) {
 			if (chosen[i])
 				result[j++] = i;
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 2471297f71..8164b581a6 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -1021,7 +1021,7 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
 		const char **refspecs_str;
 		int i;
 
-		refspecs_str = xmalloc(sizeof(*refspecs_str) * refspecs_list.nr);
+		ALLOC_ARRAY(refspecs_str, refspecs_list.nr);
 		for (i = 0; i < refspecs_list.nr; i++)
 			refspecs_str[i] = refspecs_list.items[i].string;
 
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index cf3019e05b..7d5914f921 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -10,33 +10,24 @@ static const char fetch_pack_usage[] =
 "[--include-tag] [--upload-pack=<git-upload-pack>] [--depth=<n>] "
 "[--no-progress] [--diag-url] [-v] [<host>:]<directory> [<refs>...]";
 
-static void add_sought_entry_mem(struct ref ***sought, int *nr, int *alloc,
-				 const char *name, int namelen)
+static void add_sought_entry(struct ref ***sought, int *nr, int *alloc,
+			     const char *name)
 {
-	struct ref *ref = xcalloc(1, sizeof(*ref) + namelen + 1);
+	struct ref *ref;
 	struct object_id oid;
-	const int chunksz = GIT_SHA1_HEXSZ + 1;
 
-	if (namelen > chunksz && name[chunksz - 1] == ' ' &&
-		!get_oid_hex(name, &oid)) {
-		oidcpy(&ref->old_oid, &oid);
-		name += chunksz;
-		namelen -= chunksz;
-	}
+	if (!get_oid_hex(name, &oid) && name[GIT_SHA1_HEXSZ] == ' ')
+		name += GIT_SHA1_HEXSZ + 1;
+	else
+		oidclr(&oid);
 
-	memcpy(ref->name, name, namelen);
-	ref->name[namelen] = '\0';
+	ref = alloc_ref(name);
+	oidcpy(&ref->old_oid, &oid);
 	(*nr)++;
 	ALLOC_GROW(*sought, *nr, *alloc);
 	(*sought)[*nr - 1] = ref;
 }
 
-static void add_sought_entry(struct ref ***sought, int *nr, int *alloc,
-			     const char *string)
-{
-	add_sought_entry_mem(sought, nr, alloc, string, strlen(string));
-}
-
 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 {
 	int i, ret;
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 17f40e10f6..683f08ec91 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1107,7 +1107,7 @@ static int fetch_one(struct remote *remote, int argc, const char **argv)
 	if (argc > 0) {
 		int j = 0;
 		int i;
-		refs = xcalloc(argc + 1, sizeof(const char *));
+		refs = xcalloc(st_add(argc, 1), sizeof(const char *));
 		for (i = 0; i < argc; i++) {
 			if (!strcmp(argv[i], "tag")) {
 				i++;
diff --git a/builtin/grep.c b/builtin/grep.c
index 3ba35ecf93..65c02010c7 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -354,17 +354,17 @@ static void append_path(struct grep_opt *opt, const void *data, size_t len)
 static void run_pager(struct grep_opt *opt, const char *prefix)
 {
 	struct string_list *path_list = opt->output_priv;
-	const char **argv = xmalloc(sizeof(const char *) * (path_list->nr + 1));
+	struct child_process child = CHILD_PROCESS_INIT;
 	int i, status;
 
 	for (i = 0; i < path_list->nr; i++)
-		argv[i] = path_list->items[i].string;
-	argv[path_list->nr] = NULL;
+		argv_array_push(&child.args, path_list->items[i].string);
+	child.dir = prefix;
+	child.use_shell = 1;
 
-	status = run_command_v_opt_cd_env(argv, RUN_USING_SHELL, prefix, NULL);
+	status = run_command(&child);
 	if (status)
 		exit(status);
-	free(argv);
 }
 
 static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int cached)
diff --git a/builtin/help.c b/builtin/help.c
index 1cd0c1ee44..3c55ce4563 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -171,12 +171,10 @@ static void exec_man_cmd(const char *cmd, const char *page)
 static void add_man_viewer(const char *name)
 {
 	struct man_viewer_list **p = &man_viewer_list;
-	size_t len = strlen(name);
 
 	while (*p)
 		p = &((*p)->next);
-	*p = xcalloc(1, (sizeof(**p) + len + 1));
-	memcpy((*p)->name, name, len); /* NUL-terminated by xcalloc */
+	FLEX_ALLOC_STR(*p, name, name);
 }
 
 static int supported_man_viewer(const char *name, size_t len)
@@ -190,9 +188,8 @@ static void do_add_man_viewer_info(const char *name,
 				   size_t len,
 				   const char *value)
 {
-	struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
-
-	memcpy(new->name, name, len); /* NUL-terminated by xcalloc */
+	struct man_viewer_info_list *new;
+	FLEX_ALLOC_MEM(new, name, name, len);
 	new->info = xstrdup(value);
 	new->next = man_viewer_info_list;
 	man_viewer_info_list = new;
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 6a01509587..193908a619 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1346,7 +1346,7 @@ static void fix_unresolved_deltas(struct sha1file *f)
 	 * before deltas depending on them, a good heuristic is to start
 	 * resolving deltas in the same order as their position in the pack.
 	 */
-	sorted_by_pos = xmalloc(nr_ref_deltas * sizeof(*sorted_by_pos));
+	ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
 	for (i = 0; i < nr_ref_deltas; i++)
 		sorted_by_pos[i] = &ref_deltas[i];
 	qsort(sorted_by_pos, nr_ref_deltas, sizeof(*sorted_by_pos), delta_pos_compare);
@@ -1744,9 +1744,9 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 
 	curr_pack = open_pack_file(pack_name);
 	parse_pack_header();
-	objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
+	objects = xcalloc(st_add(nr_objects, 1), sizeof(struct object_entry));
 	if (show_stat)
-		obj_stat = xcalloc(nr_objects + 1, sizeof(struct object_stat));
+		obj_stat = xcalloc(st_add(nr_o