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[PATCH 4/3] parse-options: make compiler check value type mismatch

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
May 24, 2019, 09:36 UTC
Message-ID
<20190524093611.1165-1-pclouds@gmail.com>
In-Reply-To
<20190524092442.701-1-pclouds@gmail.com>

There is a disconnect between the actual value type from parse-options user and the parser itself. This is because we have to store 'value' pointer as 'void *' and the compiler cannot help point out that the user is passing a 'long' while the parser expects an 'int'. This could lead to memory corruption.

In order to spot these type mismatch problems, a dummy inline function is used to process the 'value' input with the right type, before the input is stored in 'struct option'. This gives the compiler some context to start complaining.

The catch though, is that we can only call a function in variable declaration if it's in automatic scope. Global and static 'struct option' variables will fail to build after this. But I think this is an reasonable price to pay, compared to memory corruption.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 For the record, this is what I used to make patch 1/3 (I don't think I
 could just rely on manual code inspection to catch these problems)
 If we are doing something like this, then we have some clean up to do
 first. I think it's worth doing though. But maybe there's a better way?
 parse-options.h | 50 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 19 deletions(-)
diff --git a/parse-options.h b/parse-options.h
index ac6ba8abf9..b6ea0ac66d 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -128,55 +128,67 @@ struct option {
 	intptr_t extra;
 };
 
-#define OPT_BIT_F(s, l, v, h, b, f) { OPTION_BIT, (s), (l), (v), NULL, (h), \
+#define DEFINE_OPT_TYPE_CHECK(name, type)  \
+	static inline void *_opt_ ## name(type *p)	\
+	{						\
+		return p;				\
+	}
+
+DEFINE_OPT_TYPE_CHECK(int, int)
+DEFINE_OPT_TYPE_CHECK(ulong, unsigned long)
+DEFINE_OPT_TYPE_CHECK(string, const char *)
+DEFINE_OPT_TYPE_CHECK(string_list, struct string_list)
+DEFINE_OPT_TYPE_CHECK(timestamp, timestamp_t)
+
+#define OPT_BIT_F(s, l, v, h, b, f) { OPTION_BIT, (s), (l), _opt_int(v), NULL, (h), \
 				      PARSE_OPT_NOARG|(f), NULL, (b) }
-#define OPT_COUNTUP_F(s, l, v, h, f) { OPTION_COUNTUP, (s), (l), (v), NULL, \
+#define OPT_COUNTUP_F(s, l, v, h, f) { OPTION_COUNTUP, (s), (l), _opt_int(v), NULL, \
 				       (h), PARSE_OPT_NOARG|(f) }
-#define OPT_SET_INT_F(s, l, v, h, i, f) { OPTION_SET_INT, (s), (l), (v), NULL, \
+#define OPT_SET_INT_F(s, l, v, h, i, f) { OPTION_SET_INT, (s), (l), _opt_int(v), NULL, \
 					  (h), PARSE_OPT_NOARG | (f), NULL, (i) }
 #define OPT_BOOL_F(s, l, v, h, f)   OPT_SET_INT_F(s, l, v, h, 1, f)
 #define OPT_CALLBACK_F(s, l, v, a, h, f, cb)			\
 	{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), (cb) }
-#define OPT_STRING_F(s, l, v, a, h, f)   { OPTION_STRING,  (s), (l), (v), (a), (h), (f) }
-#define OPT_INTEGER_F(s, l, v, h, f)     { OPTION_INTEGER, (s), (l), (v), N_("n"), (h), (f) }
+#define OPT_STRING_F(s, l, v, a, h, f)   { OPTION_STRING,  (s), (l), _opt_string(v), (a), (h), (f) }
+#define OPT_INTEGER_F(s, l, v, h, f)     { OPTION_INTEGER, (s), (l), _opt_int(v), N_("n"), (h), (f) }
 
 #define OPT_END()                   { OPTION_END }
-#define OPT_ARGUMENT(l, v, h)       { OPTION_ARGUMENT, 0, (l), (v), NULL, \
+#define OPT_ARGUMENT(l, v, h)       { OPTION_ARGUMENT, 0, (l), _opt_int(v), NULL, \
 				      (h), PARSE_OPT_NOARG, NULL, 1 }
 #define OPT_GROUP(h)                { OPTION_GROUP, 0, NULL, NULL, NULL, (h) }
 #define OPT_BIT(s, l, v, h, b)      OPT_BIT_F(s, l, v, h, b, 0)
-#define OPT_BITOP(s, l, v, h, set, clear) { OPTION_BITOP, (s), (l), (v), NULL, (h), \
+#define OPT_BITOP(s, l, v, h, set, clear) { OPTION_BITOP, (s), (l), _opt_int(v), NULL, (h), \
 					    PARSE_OPT_NOARG|PARSE_OPT_NONEG, NULL, \
 					    (set), NULL, (clear) }
-#define OPT_NEGBIT(s, l, v, h, b)   { OPTION_NEGBIT, (s), (l), (v), NULL, \
+#define OPT_NEGBIT(s, l, v, h, b)   { OPTION_NEGBIT, (s), (l), _opt_int(v), NULL, \
 				      (h), PARSE_OPT_NOARG, NULL, (b) }
 #define OPT_COUNTUP(s, l, v, h)     OPT_COUNTUP_F(s, l, v, h, 0)
 #define OPT_SET_INT(s, l, v, h, i)  OPT_SET_INT_F(s, l, v, h, i, 0)
 #define OPT_BOOL(s, l, v, h)        OPT_BOOL_F(s, l, v, h, 0)
-#define OPT_HIDDEN_BOOL(s, l, v, h) { OPTION_SET_INT, (s), (l), (v), NULL, \
+#define OPT_HIDDEN_BOOL(s, l, v, h) { OPTION_SET_INT, (s), (l), _opt_int(v), NULL, \
 				      (h), PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1}
-#define OPT_CMDMODE(s, l, v, h, i)  { OPTION_CMDMODE, (s), (l), (v), NULL, \
+#define OPT_CMDMODE(s, l, v, h, i)  { OPTION_CMDMODE, (s), (l), _opt_int(v), NULL, \
 				      (h), PARSE_OPT_NOARG|PARSE_OPT_NONEG, NULL, (i) }
 #define OPT_INTEGER(s, l, v, h)     OPT_INTEGER_F(s, l, v, h, 0)
-#define OPT_MAGNITUDE(s, l, v, h)   { OPTION_MAGNITUDE, (s), (l), (v), \
+#define OPT_MAGNITUDE(s, l, v, h)   { OPTION_MAGNITUDE, (s), (l), _opt_ulong(v), \
 				      N_("n"), (h), PARSE_OPT_NONEG }
 #define OPT_STRING(s, l, v, a, h)   OPT_STRING_F(s, l, v, a, h, 0)
 #define OPT_STRING_LIST(s, l, v, a, h) \
-				    { OPTION_CALLBACK, (s), (l), (v), (a), \
+				    { OPTION_CALLBACK, (s), (l), _opt_string_list(v), (a), \
 				      (h), 0, &parse_opt_string_list }
-#define OPT_UYN(s, l, v, h)         { OPTION_CALLBACK, (s), (l), (v), NULL, \
+#define OPT_UYN(s, l, v, h)         { OPTION_CALLBACK, (s), (l), _opt_int(v), NULL, \
 				      (h), PARSE_OPT_NOARG, &parse_opt_tertiary }
 #define OPT_EXPIRY_DATE(s, l, v, h) \
-	{ OPTION_CALLBACK, (s), (l), (v), N_("expiry-date"),(h), 0,	\
+	{ OPTION_CALLBACK, (s), (l), _opt_timestamp(v), N_("expiry-date"),(h), 0,	\
 	  parse_opt_expiry_date_cb }
 #define OPT_CALLBACK(s, l, v, a, h, f) OPT_CALLBACK_F(s, l, v, a, h, 0, f)
 #define OPT_NUMBER_CALLBACK(v, h, f) \
 	{ OPTION_NUMBER, 0, NULL, (v), NULL, (h), \
 	  PARSE_OPT_NOARG | PARSE_OPT_NONEG, (f) }
-#define OPT_FILENAME(s, l, v, h)    { OPTION_FILENAME, (s), (l), (v), \
+#define OPT_FILENAME(s, l, v, h)    { OPTION_FILENAME, (s), (l), _opt_string(v), \
 				       N_("file"), (h) }
 #define OPT_COLOR_FLAG(s, l, v, h) \
-	{ OPTION_CALLBACK, (s), (l), (v), N_("when"), (h), PARSE_OPT_OPTARG, \
+	{ OPTION_CALLBACK, (s), (l), _opt_int(v), N_("when"), (h), PARSE_OPT_OPTARG, \
 		parse_opt_color_flag_cb, (intptr_t)"always" }
 
 #define OPT_NOOP_NOARG(s, l) \
@@ -301,14 +313,14 @@ int parse_opt_passthru_argv(const struct option *, const char *, int);
 #define OPT__VERBOSE(var, h)  OPT_COUNTUP('v', "verbose", (var), (h))
 #define OPT__QUIET(var, h)    OPT_COUNTUP('q', "quiet",   (var), (h))
 #define OPT__VERBOSITY(var) \
-	{ OPTION_CALLBACK, 'v', "verbose", (var), NULL, N_("be more verbose"), \
+	{ OPTION_CALLBACK, 'v', "verbose", _opt_int(var), NULL, N_("be more verbose"), \
 	  PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }, \
-	{ OPTION_CALLBACK, 'q', "quiet", (var), NULL, N_("be more quiet"), \
+	{ OPTION_CALLBACK, 'q', "quiet", _opt_int(var), NULL, N_("be more quiet"), \
 	  PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }
 #define OPT__DRY_RUN(var, h)  OPT_BOOL('n', "dry-run", (var), (h))
 #define OPT__FORCE(var, h, f) OPT_COUNTUP_F('f', "force",   (var), (h), (f))
 #define OPT__ABBREV(var)  \
-	{ OPTION_CALLBACK, 0, "abbrev", (var), N_("n"),	\
+	{ OPTION_CALLBACK, 0, "abbrev", _opt_int(var), N_("n"),	\
 	  N_("use <n> digits to display SHA-1s"),	\
 	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
 #define OPT__COLOR(var, h) \

-- 
2.22.0.rc0.322.g2b0371e29a
Previous: Nguyễn Thái Ngọc DuyNext: Todd Zullinger
Message 6 of 18 in “fix diff-parseopt regressions”
  1. 0/3 fix diff-parseopt regressionsNguyễn Thái Ngọc Duy, May 24, 2019
  2. 1/3 diff-parseopt: correct variable types that are used by parseoptNguyễn Thái Ngọc Duy, May 24, 2019
  3. Junio C HamanoMay 28, 2019
  4. 2/3 diff-parseopt: restore -U (no argument) behaviorNguyễn Thái Ngọc Duy, May 24, 2019
  5. 3/3 parse-options: check empty value in OPT_INTEGER and OPT_ABBREVNguyễn Thái Ngọc Duy, May 24, 2019
  6. 4/3 parse-options: make compiler check value type mismatchNguyễn Thái Ngọc Duy, May 24, 2019
  7. Todd ZullingerMay 24, 2019
  8. Todd ZullingerMay 24, 2019
  9. Duy NguyenMay 25, 2019
  10. Todd ZullingerMay 25, 2019
  11. 0/3 fix diff-parseopt regressionsNguyễn Thái Ngọc Duy, May 29, 2019
  12. 1/3 diff-parseopt: correct variable types that are used by parseoptNguyễn Thái Ngọc Duy, May 29, 2019
  13. Eric SunshineMay 29, 2019
  14. Todd ZullingerMay 29, 2019
  15. Junio C HamanoMay 29, 2019
  16. 2/3 diff-parseopt: restore -U (no argument) behaviorNguyễn Thái Ngọc Duy, May 29, 2019
  17. 3/3 parse-options: check empty value in OPT_INTEGER and OPT_ABBREVNguyễn Thái Ngọc Duy, May 29, 2019
  18. Junio C HamanoMay 29, 2019

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