xref: /llvm-project/clang/test/Sema/format-strings.c (revision c9dd94685283938a2d9227a0fa448f08d7b19ab4)
1 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral %s
2 
3 #include <stdarg.h>
4 typedef __typeof(sizeof(int)) size_t;
5 typedef struct _FILE FILE;
6 int fprintf(FILE *, const char *restrict, ...);
7 int printf(const char *restrict, ...); // expected-note{{passing argument to parameter here}}
8 int snprintf(char *restrict, size_t, const char *restrict, ...);
9 int sprintf(char *restrict, const char *restrict, ...);
10 int vasprintf(char **, const char *, va_list);
11 int asprintf(char **, const char *, ...);
12 int vfprintf(FILE *, const char *restrict, va_list);
13 int vprintf(const char *restrict, va_list);
14 int vsnprintf(char *, size_t, const char *, va_list);
15 int vsprintf(char *restrict, const char *restrict, va_list); // expected-note{{passing argument to parameter here}}
16 
17 int vscanf(const char *restrict format, va_list arg);
18 
19 char * global_fmt;
20 
21 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
22 
23   char * b;
24   va_list ap;
25   va_start(ap,buf);
26 
27   printf(s); // expected-warning {{format string is not a string literal}}
28   vprintf(s,ap); // expected-warning {{format string is not a string literal}}
29   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
30   vfprintf(fp,s,ap); // expected-warning {{format string is not a string literal}}
31   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
32   vasprintf(&b,s,ap); // expected-warning {{format string is not a string literal}}
33   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
34   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
35   __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
36   __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
37   vsprintf(buf,s,ap); // expected-warning {{format string is not a string lit}}
38   vsnprintf(buf,2,s,ap); // expected-warning {{format string is not a string lit}}
39   vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
40   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // expected-warning {{format string is not a string lit}}
41   __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
42 
43   vscanf(s, ap); // expected-warning {{format string is not a string literal}}
44 
45   // rdar://6079877
46   printf("abc"
47          "%*d", 1, 1); // no-warning
48   printf("abc\
49 def"
50          "%*d", 1, 1); // no-warning
51 
52   // <rdar://problem/6079850>, allow 'unsigned' (instead of 'int') to be used for both
53   // the field width and precision.  This deviates from C99, but is reasonably safe
54   // and is also accepted by GCC.
55   printf("%*d", (unsigned) 1, 1); // no-warning
56 }
57 
58 __attribute__((__format__ (__printf__, 2, 4)))
59 void check_string_literal2( FILE* fp, const char* s, char *buf, ... ) {
60   char * b;
61   va_list ap;
62   va_start(ap,buf);
63 
64   printf(s); // expected-warning {{format string is not a string literal}}
65   vprintf(s,ap); // no-warning
66   fprintf(fp,s); // expected-warning {{format string is not a string literal}}
67   vfprintf(fp,s,ap); // no-warning
68   asprintf(&b,s); // expected-warning {{format string is not a string lit}}
69   vasprintf(&b,s,ap); // no-warning
70   sprintf(buf,s); // expected-warning {{format string is not a string literal}}
71   snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
72   __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
73 
74   vscanf(s, ap); // expected-warning {{format string is not a string literal}}
75 }
76 
77 void check_conditional_literal(const char* s, int i) {
78   printf(i == 1 ? "yes" : "no"); // no-warning
79   printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
80   printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
81   printf("yes" ?: "no %d", 1); // expected-warning{{data argument not used by format string}}
82 }
83 
84 void check_writeback_specifier()
85 {
86   int x;
87   char *b;
88 
89   printf("%n",&x); // expected-warning {{'%n' in format string discouraged}}
90   sprintf(b,"%d%%%n",1, &x); // expected-warning {{'%n' in format string dis}}
91 }
92 
93 void check_invalid_specifier(FILE* fp, char *buf)
94 {
95   printf("%s%lb%d","unix",10,20); // expected-warning {{invalid conversion specifier 'b'}}
96   fprintf(fp,"%%%l"); // expected-warning {{incomplete format specifier}}
97   sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
98   snprintf(buf, 2, "%%%%%ld%;%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}} expected-warning {{invalid conversion specifier ';'}}
99 }
100 
101 void check_null_char_string(char* b)
102 {
103   printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
104   snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
105   printf("%\0d",1); // expected-warning {{string contains '\0'}}
106 }
107 
108 void check_empty_format_string(char* buf, ...)
109 {
110   va_list ap;
111   va_start(ap,buf);
112   vprintf("",ap); // expected-warning {{format string is empty}}
113   sprintf(buf, "", 1); // expected-warning {{format string is empty}}
114 
115   // Don't warn about empty format strings when there are no data arguments.
116   // This can arise from macro expansions and non-standard format string
117   // functions.
118   sprintf(buf, ""); // no-warning
119 }
120 
121 void check_wide_string(char* b, ...)
122 {
123   va_list ap;
124   va_start(ap,b);
125 
126   printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
127   vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
128 }
129 
130 void check_asterisk_precision_width(int x) {
131   printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
132   printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
133   printf("%*d",12,x); // no-warning
134   printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
135   printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
136 }
137 
138 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
139 
140 void test_myprintf() {
141   myprintf("%d", 17, 18); // okay
142 }
143 
144 void test_constant_bindings(void) {
145   const char * const s1 = "hello";
146   const char s2[] = "hello";
147   const char *s3 = "hello";
148   char * const s4 = "hello";
149   extern const char s5[];
150 
151   printf(s1); // no-warning
152   printf(s2); // no-warning
153   printf(s3); // expected-warning{{not a string literal}}
154   printf(s4); // expected-warning{{not a string literal}}
155   printf(s5); // expected-warning{{not a string literal}}
156 }
157 
158 
159 // Test what happens when -Wformat-security only.
160 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
161 #pragma GCC diagnostic warning "-Wformat-security"
162 
163 void test9(char *P) {
164   int x;
165   printf(P);   // expected-warning {{format string is not a string literal (potentially insecure)}}
166   printf(P, 42);
167   printf("%n", &x); // expected-warning {{use of '%n' in format string discouraged }}
168 }
169 
170 void torture(va_list v8) {
171   vprintf ("%*.*d", v8);  // no-warning
172 
173 }
174 
175 void test10(int x, float f, int i, long long lli) {
176   printf("%s"); // expected-warning{{more '%' conversions than data arguments}}
177   printf("%@", 12); // expected-warning{{invalid conversion specifier '@'}}
178   printf("\0"); // expected-warning{{format string contains '\0' within the string body}}
179   printf("xs\0"); // expected-warning{{format string contains '\0' within the string body}}
180   printf("%*d\n"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
181   printf("%*.*d\n", x); // expected-warning{{'.*' specified field precision is missing a matching 'int' argument}}
182   printf("%*d\n", f, x); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
183   printf("%*.*d\n", x, f, x); // expected-warning{{field precision should have type 'int', but argument has type 'double'}}
184   printf("%**\n"); // expected-warning{{invalid conversion specifier '*'}}
185   printf("%n", &i); // expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
186   printf("%d%d\n", x); // expected-warning{{more '%' conversions than data arguments}}
187   printf("%d\n", x, x); // expected-warning{{data argument not used by format string}}
188   printf("%W%d%Z\n", x, x, x); // expected-warning{{invalid conversion specifier 'W'}} expected-warning{{invalid conversion specifier 'Z'}}
189   printf("%"); // expected-warning{{incomplete format specifier}}
190   printf("%.d", x); // no-warning
191   printf("%.", x);  // expected-warning{{incomplete format specifier}}
192   printf("%f", 4); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
193   printf("%qd", lli); // no-warning
194   printf("%qd", x); // expected-warning{{format specifies type 'long long' but the argument has type 'int'}}
195   printf("%qp", (void *)0); // expected-warning{{length modifier 'q' results in undefined behavior or no effect with 'p' conversion specifier}}
196   printf("hhX %hhX", (unsigned char)10); // no-warning
197   printf("llX %llX", (long long) 10); // no-warning
198   // This is fine, because there is an implicit conversion to an int.
199   printf("%d", (unsigned char) 10); // no-warning
200   printf("%d", (long long) 10); // expected-warning{{format specifies type 'int' but the argument has type 'long long'}}
201   printf("%Lf\n", (long double) 1.0); // no-warning
202   printf("%f\n", (long double) 1.0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
203   // The man page says that a zero precision is okay.
204   printf("%.0Lf", (long double) 1.0); // no-warning
205   printf("%c\n", "x"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
206   printf("%c\n", 1.23); // expected-warning{{format specifies type 'int' but the argument has type 'double'}}
207   printf("Format %d, is %! %f", 1, 2, 4.4); // expected-warning{{invalid conversion specifier '!'}}
208 }
209 
210 typedef unsigned char uint8_t;
211 
212 void should_understand_small_integers() {
213   printf("%hhu", (short) 10); // expected-warning{{format specifies type 'unsigned char' but the argument has type 'short'}}
214   printf("%hu\n", (unsigned char) 1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'unsigned char'}}
215   printf("%hu\n", (uint8_t)1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'uint8_t'}}
216 }
217 
218 void test11(void *p, char *s) {
219   printf("%p", p); // no-warning
220   printf("%p", 123); // expected-warning{{format specifies type 'void *' but the argument has type 'int'}}
221   printf("%.4p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
222   printf("%+p", p); // expected-warning{{flag '+' results in undefined behavior with 'p' conversion specifier}}
223   printf("% p", p); // expected-warning{{flag ' ' results in undefined behavior with 'p' conversion specifier}}
224   printf("%0p", p); // expected-warning{{flag '0' results in undefined behavior with 'p' conversion specifier}}
225   printf("%s", s); // no-warning
226   printf("%+s", p); // expected-warning{{flag '+' results in undefined behavior with 's' conversion specifier}}
227   printf("% s", p); // expected-warning{{flag ' ' results in undefined behavior with 's' conversion specifier}}
228   printf("%0s", p); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
229 }
230 
231 void test12(char *b) {
232   unsigned char buf[4];
233   printf ("%.4s\n", buf); // no-warning
234   printf ("%.4s\n", &buf); // expected-warning{{format specifies type 'char *' but the argument has type 'unsigned char (*)[4]'}}
235 
236   // Verify that we are checking asprintf
237   asprintf(&b, "%d", "asprintf"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
238 }
239 
240 void test13(short x) {
241   char bel = 007;
242   printf("bel: '0%hhd'\n", bel); // no-warning
243   printf("x: '0%hhd'\n", x); // expected-warning {{format specifies type 'char' but the argument has type 'short'}}
244 }
245 
246 typedef struct __aslclient *aslclient;
247 typedef struct __aslmsg *aslmsg;
248 int asl_log(aslclient asl, aslmsg msg, int level, const char *format, ...) __attribute__((__format__ (__printf__, 4, 5)));
249 void test_asl(aslclient asl) {
250   // Test case from <rdar://problem/7341605>.
251   asl_log(asl, 0, 3, "Error: %m"); // no-warning
252   asl_log(asl, 0, 3, "Error: %W"); // expected-warning{{invalid conversion specifier 'W'}}
253 }
254 
255 // <rdar://problem/7595366>
256 typedef enum { A } int_t;
257 void f0(int_t x) { printf("%d\n", x); }
258 
259 // Unicode test cases.  These are possibly specific to Mac OS X.  If so, they should
260 // eventually be moved into a separate test.
261 typedef __WCHAR_TYPE__ wchar_t;
262 
263 void test_unicode_conversions(wchar_t *s) {
264   printf("%S", s); // no-warning
265   printf("%s", s); // expected-warning{{format specifies type 'char *' but the argument has type 'wchar_t *'}}
266   printf("%C", s[0]); // no-warning
267   printf("%c", s[0]);
268   // FIXME: This test reports inconsistent results. On Windows, '%C' expects
269   // 'unsigned short'.
270   // printf("%C", 10);
271   printf("%S", "hello"); // expected-warning{{but the argument has type 'char *'}}
272 }
273 
274 // Mac OS X supports positional arguments in format strings.
275 // This is an IEEE extension (IEEE Std 1003.1).
276 // FIXME: This is probably not portable everywhere.
277 void test_positional_arguments() {
278   printf("%0$", (int)2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
279   printf("%1$*0$d", (int) 2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
280   printf("%1$d", (int) 2); // no-warning
281   printf("%1$d", (int) 2, 2); // expected-warning{{data argument not used by format string}}
282   printf("%1$d%1$f", (int) 2); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
283   printf("%1$2.2d", (int) 2); // no-warning
284   printf("%2$*1$.2d", (int) 2, (int) 3); // no-warning
285   printf("%2$*8$d", (int) 2, (int) 3); // expected-warning{{specified field width is missing a matching 'int' argument}}
286   printf("%%%1$d", (int) 2); // no-warning
287   printf("%1$d%%", (int) 2); // no-warning
288 }
289 
290 // PR 6697 - Handle format strings where the data argument is not adjacent to the format string
291 void myprintf_PR_6697(const char *format, int x, ...) __attribute__((__format__(printf,1, 3)));
292 void test_pr_6697() {
293   myprintf_PR_6697("%s\n", 1, "foo"); // no-warning
294   myprintf_PR_6697("%s\n", 1, (int)0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
295   // FIXME: Not everything should clearly support positional arguments,
296   // but we need a way to identify those cases.
297   myprintf_PR_6697("%1$s\n", 1, "foo"); // no-warning
298   myprintf_PR_6697("%2$s\n", 1, "foo"); // expected-warning{{data argument position '2' exceeds the number of data arguments (1)}}
299   myprintf_PR_6697("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (1)}}
300   myprintf_PR_6697("%1$s\n", 1, (int) 0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
301 }
302 
303 void rdar8026030(FILE *fp) {
304   fprintf(fp, "\%"); // expected-warning{{incomplete format specifier}}
305 }
306 
307 void bug7377_bad_length_mod_usage() {
308   // Bad length modifiers
309   printf("%hhs", "foo"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
310   printf("%1$zp", (void *)0); // expected-warning{{length modifier 'z' results in undefined behavior or no effect with 'p' conversion specifier}}
311   printf("%ls", L"foo"); // no-warning
312   printf("%#.2Lf", (long double)1.234); // no-warning
313 
314   // Bad flag usage
315   printf("%#p", (void *) 0); // expected-warning{{flag '#' results in undefined behavior with 'p' conversion specifier}}
316   printf("%0d", -1); // no-warning
317   printf("%#n", (void *) 0); // expected-warning{{flag '#' results in undefined behavior with 'n' conversion specifier}} expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
318   printf("%-n", (void *) 0); // expected-warning{{flag '-' results in undefined behavior with 'n' conversion specifier}} expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
319   printf("%-p", (void *) 0); // no-warning
320 
321   // Bad optional amount use
322   printf("%.2c", 'a'); // expected-warning{{precision used with 'c' conversion specifier, resulting in undefined behavior}}
323   printf("%1n", (void *) 0); // expected-warning{{field width used with 'n' conversion specifier, resulting in undefined behavior}} expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
324   printf("%.9n", (void *) 0); // expected-warning{{precision used with 'n' conversion specifier, resulting in undefined behavior}} expected-warning{{use of '%n' in format string discouraged (potentially insecure)}}
325 
326   // Ignored flags
327   printf("% +f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
328   printf("%+ f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
329   printf("%0-f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
330   printf("%-0f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
331   printf("%-+f", 1.23); // no-warning
332 }
333 
334 // PR 7981 - handle '%lc' (wint_t)
335 #ifndef wint_t
336 typedef int __darwin_wint_t;
337 typedef __darwin_wint_t wint_t;
338 #endif
339 
340 void pr7981(wint_t c, wchar_t c2) {
341   printf("%lc", c); // no-warning
342   printf("%lc", 1.0); // expected-warning{{the argument has type 'double'}}
343   printf("%lc", (char) 1); // no-warning
344   printf("%lc", &c); // expected-warning{{the argument has type 'wint_t *' (aka 'int *')}}
345   printf("%lc", c2); // no-warning
346 }
347 
348 // <rdar://problem/8269537> -Wformat-security says NULL is not a string literal
349 void rdar8269537() {
350   // This is likely to crash in most cases, but -Wformat-nonliteral technically
351   // doesn't warn in this case.
352   printf(0); // no-warning
353 }
354 
355 // Handle functions with multiple format attributes.
356 extern void rdar8332221_vprintf_scanf(const char *, va_list, const char *, ...)
357      __attribute__((__format__(__printf__, 1, 0)))
358      __attribute__((__format__(__scanf__, 3, 4)));
359 
360 void rdar8332221(va_list ap, int *x, long *y) {
361   rdar8332221_vprintf_scanf("%", ap, "%d", x); // expected-warning{{incomplete format specifier}}
362 }
363 
364 // PR8641
365 void pr8641() {
366   printf("%#x\n", 10);
367   printf("%#X\n", 10);
368 }
369 
370 void posix_extensions() {
371   // Test %'d, "thousands grouping".
372   // <rdar://problem/8816343>
373   printf("%'d\n", 123456789); // no-warning
374   printf("%'i\n", 123456789); // no-warning
375   printf("%'f\n", (float) 1.0); // no-warning
376   printf("%'p\n", (void*) 0); // expected-warning{{results in undefined behavior with 'p' conversion specifier}}
377 }
378 
379 // PR8486
380 //
381 // Test what happens when -Wformat is on, but -Wformat-security is off.
382 #pragma GCC diagnostic warning "-Wformat"
383 #pragma GCC diagnostic ignored "-Wformat-security"
384 
385 void pr8486() {
386   printf("%s", 1); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
387 }
388 
389 // PR9314
390 // Don't warn about string literals that are PreDefinedExprs, e.g. __func__.
391 void pr9314() {
392   printf(__PRETTY_FUNCTION__); // no-warning
393   printf(__func__); // no-warning
394 }
395 
396 int printf(const char * restrict, ...) __attribute__((__format__ (__printf__, 1, 2)));
397 
398 void rdar9612060(void) {
399   printf("%s", 2); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
400 }
401 
402 void check_char(unsigned char x, signed char y) {
403   printf("%c", y); // no-warning
404   printf("%hhu", x); // no-warning
405   printf("%hhi", y); // no-warning
406   printf("%hhi", x); // no-warning
407   printf("%c", x); // no-warning
408   printf("%hhu", y); // no-warning
409 }
410 
411 // Test suppression of individual warnings.
412 
413 void test_suppress_invalid_specifier() {
414 #pragma clang diagnostic push
415 #pragma clang diagnostic ignored "-Wformat-invalid-specifier"
416   printf("%@", 12); // no-warning
417 #pragma clang diagnostic pop
418 }
419 
420 // Make sure warnings are on for next test.
421 #pragma GCC diagnostic warning "-Wformat"
422 #pragma GCC diagnostic warning "-Wformat-security"
423 
424 // Test that the printf call site is where the warning is attached.  If the
425 // format string is somewhere else, point to it in a note.
426 void pr9751() {
427   const char kFormat1[] = "%d %d \n"; // expected-note{{format string is defined here}}}
428   printf(kFormat1, 0); // expected-warning{{more '%' conversions than data arguments}}
429   printf("%d %s\n", 0); // expected-warning{{more '%' conversions than data arguments}}
430 
431   const char kFormat2[] = "%18$s\n"; // expected-note{{format string is defined here}}
432   printf(kFormat2, 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
433   printf("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
434 
435   const char kFormat3[] = "%n"; // expected-note{{format string is defined here}}
436   printf(kFormat3, "as"); // expected-warning{{use of '%n' in format string discouraged}}
437   printf("%n", "as"); // expected-warning{{use of '%n' in format string discouraged}}
438 
439   const char kFormat4[] = "%y"; // expected-note{{format string is defined here}}
440   printf(kFormat4, 5); // expected-warning{{invalid conversion specifier 'y'}}
441   printf("%y", 5); // expected-warning{{invalid conversion specifier 'y'}}
442 
443   const char kFormat5[] = "%."; // expected-note{{format string is defined here}}
444   printf(kFormat5, 5); // expected-warning{{incomplete format specifier}}
445   printf("%.", 5); // expected-warning{{incomplete format specifier}}
446 
447   const char kFormat6[] = "%s"; // expected-note{{format string is defined here}}
448   printf(kFormat6, 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
449   printf("%s", 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
450 
451   const char kFormat7[] = "%0$"; // expected-note{{format string is defined here}}
452   printf(kFormat7, 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
453   printf("%0$", 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
454 
455   const char kFormat8[] = "%1$d %d"; // expected-note{{format string is defined here}}
456   printf(kFormat8, 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
457   printf("%1$d %d", 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
458 
459   const char kFormat9[] = ""; // expected-note{{format string is defined here}}
460   printf(kFormat9, 4, 4); // expected-warning{{format string is empty}}
461   printf("", 4, 4); // expected-warning{{format string is empty}}
462 
463   const char kFormat10[] = "\0%d"; // expected-note{{format string is defined here}}
464   printf(kFormat10, 4); // expected-warning{{format string contains '\0' within the string body}}
465   printf("\0%d", 4); // expected-warning{{format string contains '\0' within the string body}}
466 
467   const char kFormat11[] = "%*d"; // expected-note{{format string is defined here}}
468   printf(kFormat11); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
469   printf("%*d"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
470 
471   const char kFormat12[] = "%*d"; // expected-note{{format string is defined here}}
472   printf(kFormat12, 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
473   printf("%*d", 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
474 
475   const char kFormat13[] = "%.3p"; // expected-note{{format string is defined here}}
476   void *p;
477   printf(kFormat13, p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
478   printf("%.3p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
479 
480   const char kFormat14[] = "%0s"; // expected-note{{format string is defined here}}
481   printf(kFormat14, "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
482   printf("%0s", "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
483 
484   const char kFormat15[] = "%hhs"; // expected-note{{format string is defined here}}
485   printf(kFormat15, "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
486   printf("%hhs", "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
487 
488   const char kFormat16[] = "%-0d"; // expected-note{{format string is defined here}}
489   printf(kFormat16, 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
490   printf("%-0d", 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
491 
492   // Make sure that the "format string is defined here" note is not emitted
493   // when the original string is within the argument expression.
494   printf(1 ? "yes %d" : "no %d"); // expected-warning 2{{more '%' conversions than data arguments}}
495 
496   const char kFormat17[] = "%hu"; // expected-note{{format string is defined here}}}
497   printf(kFormat17, (int[]){0}); // expected-warning{{format specifies type 'unsigned short' but the argument}}
498 
499   printf("%a", (long double)0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
500 }
501 
502 // PR 9466: clang: doesn't know about %Lu, %Ld, and %Lx
503 void printf_longlong(long long x, unsigned long long y) {
504   printf("%Ld", y); // no-warning
505   printf("%Lu", y); // no-warning
506   printf("%Lx", y); // no-warning
507   printf("%Ld", x); // no-warning
508   printf("%Lu", x); // no-warning
509   printf("%Lx", x); // no-warning
510   printf("%Ls", "hello"); // expected-warning {{length modifier 'L' results in undefined behavior or no effect with 's' conversion specifier}}
511 }
512 
513 void __attribute__((format(strfmon,1,2))) monformat(const char *fmt, ...);
514 void __attribute__((format(strftime,1,0))) dateformat(const char *fmt);
515 
516 // Other formats
517 void test_other_formats() {
518   char *str = "";
519   monformat("", 1); // expected-warning{{format string is empty}}
520   monformat(str); // expected-warning{{format string is not a string literal (potentially insecure)}}
521   dateformat(""); // expected-warning{{format string is empty}}
522   dateformat(str); // no-warning (using strftime non literal is not unsafe)
523 }
524