1 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs %s
2 // RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral -isystem %S/Inputs -fno-signed-char %s
3
4 #include <stdarg.h>
5 #include <stddef.h>
6 #define __need_wint_t
7 #include <stddef.h> // For wint_t and wchar_t
8
9 typedef struct _FILE FILE;
10 int fprintf(FILE *, const char *restrict, ...);
11 int printf(const char *restrict, ...); // expected-note{{passing argument to parameter here}}
12 int snprintf(char *restrict, size_t, const char *restrict, ...);
13 int sprintf(char *restrict, const char *restrict, ...);
14 int vasprintf(char **, const char *, va_list);
15 int asprintf(char **, const char *, ...);
16 int vfprintf(FILE *, const char *restrict, va_list);
17 int vprintf(const char *restrict, va_list);
18 int vsnprintf(char *, size_t, const char *, va_list);
19 int vsprintf(char *restrict, const char *restrict, va_list); // expected-note{{passing argument to parameter here}}
20
21 int vscanf(const char *restrict format, va_list arg);
22
23 char * global_fmt;
24
check_string_literal(FILE * fp,const char * s,char * buf,...)25 void check_string_literal( FILE* fp, const char* s, char *buf, ... ) {
26
27 char * b;
28 va_list ap;
29 va_start(ap,buf);
30
31 printf(s); // expected-warning {{format string is not a string literal}}
32 // expected-note@-1{{treat the string as an argument to avoid this}}
33 vprintf(s,ap); // expected-warning {{format string is not a string literal}}
34 fprintf(fp,s); // expected-warning {{format string is not a string literal}}
35 // expected-note@-1{{treat the string as an argument to avoid this}}
36 vfprintf(fp,s,ap); // expected-warning {{format string is not a string literal}}
37 asprintf(&b,s); // expected-warning {{format string is not a string lit}}
38 // expected-note@-1{{treat the string as an argument to avoid this}}
39 vasprintf(&b,s,ap); // expected-warning {{format string is not a string literal}}
40 sprintf(buf,s); // expected-warning {{format string is not a string literal}}
41 // expected-note@-1{{treat the string as an argument to avoid this}}
42 snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
43 // expected-note@-1{{treat the string as an argument to avoid this}}
44 __builtin___sprintf_chk(buf,0,-1,s); // expected-warning {{format string is not a string literal}}
45 // expected-note@-1{{treat the string as an argument to avoid this}}
46 __builtin___snprintf_chk(buf,2,0,-1,s); // expected-warning {{format string is not a string lit}}
47 // expected-note@-1{{treat the string as an argument to avoid this}}
48 vsprintf(buf,s,ap); // expected-warning {{format string is not a string lit}}
49 vsnprintf(buf,2,s,ap); // expected-warning {{format string is not a string lit}}
50 vsnprintf(buf,2,global_fmt,ap); // expected-warning {{format string is not a string literal}}
51 __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // expected-warning {{format string is not a string lit}}
52 __builtin___vsnprintf_chk(buf,2,0,-1,global_fmt,ap); // expected-warning {{format string is not a string literal}}
53
54 vscanf(s, ap); // expected-warning {{format string is not a string literal}}
55
56 const char *const fmt = "%d"; // FIXME -- defined here
57 printf(fmt, 1, 2); // expected-warning{{data argument not used}}
58
59 // rdar://6079877
60 printf("abc"
61 "%*d", 1, 1); // no-warning
62 printf("abc\
63 def"
64 "%*d", 1, 1); // no-warning
65
66 // <rdar://problem/6079850>, allow 'unsigned' (instead of 'int') to be used for both
67 // the field width and precision. This deviates from C99, but is reasonably safe
68 // and is also accepted by GCC.
69 printf("%*d", (unsigned) 1, 1); // no-warning
70 }
71
72 // When calling a non-variadic format function (vprintf, vscanf, NSLogv, ...),
73 // warn only if the format string argument is a parameter that is not itself
74 // declared as a format string with compatible format.
75 __attribute__((__format__ (__printf__, 2, 4)))
check_string_literal2(FILE * fp,const char * s,char * buf,...)76 void check_string_literal2( FILE* fp, const char* s, char *buf, ... ) {
77 char * b;
78 va_list ap;
79 va_start(ap,buf);
80
81 printf(s); // expected-warning {{format string is not a string literal}}
82 // expected-note@-1{{treat the string as an argument to avoid this}}
83 vprintf(s,ap); // no-warning
84 fprintf(fp,s); // expected-warning {{format string is not a string literal}}
85 // expected-note@-1{{treat the string as an argument to avoid this}}
86 vfprintf(fp,s,ap); // no-warning
87 asprintf(&b,s); // expected-warning {{format string is not a string lit}}
88 // expected-note@-1{{treat the string as an argument to avoid this}}
89 vasprintf(&b,s,ap); // no-warning
90 sprintf(buf,s); // expected-warning {{format string is not a string literal}}
91 // expected-note@-1{{treat the string as an argument to avoid this}}
92 snprintf(buf,2,s); // expected-warning {{format string is not a string lit}}
93 // expected-note@-1{{treat the string as an argument to avoid this}}
94 __builtin___vsnprintf_chk(buf,2,0,-1,s,ap); // no-warning
95
96 vscanf(s, ap); // expected-warning {{format string is not a string literal}}
97 }
98
check_conditional_literal(const char * s,int i)99 void check_conditional_literal(const char* s, int i) {
100 printf(i == 1 ? "yes" : "no"); // no-warning
101 printf(i == 0 ? (i == 1 ? "yes" : "no") : "dont know"); // no-warning
102 printf(i == 0 ? (i == 1 ? s : "no") : "dont know"); // expected-warning{{format string is not a string literal}}
103 // expected-note@-1{{treat the string as an argument to avoid this}}
104 printf("yes" ?: "no %d", 1); // expected-warning{{data argument not used by format string}}
105 printf(0 ? "yes %s" : "no %d", 1); // no-warning
106 printf(0 ? "yes %d" : "no %s", 1); // expected-warning{{format specifies type 'char *'}}
107
108 printf(0 ? "yes" : "no %d", 1); // no-warning
109 printf(0 ? "yes %d" : "no", 1); // expected-warning{{data argument not used by format string}}
110 printf(1 ? "yes" : "no %d", 1); // expected-warning{{data argument not used by format string}}
111 printf(1 ? "yes %d" : "no", 1); // no-warning
112 printf(i ? "yes" : "no %d", 1); // no-warning
113 printf(i ? "yes %s" : "no %d", 1); // expected-warning{{format specifies type 'char *'}}
114 printf(i ? "yes" : "no %d", 1, 2); // expected-warning{{data argument not used by format string}}
115
116 printf(i ? "%*s" : "-", i, s); // no-warning
117 printf(i ? "yes" : 0 ? "no %*d" : "dont know %d", 1, 2); // expected-warning{{data argument not used by format string}}
118 printf(i ? "%i\n" : "%i %s %s\n", i, s); // expected-warning{{more '%' conversions than data arguments}}
119 }
120
check_writeback_specifier()121 void check_writeback_specifier()
122 {
123 int x;
124 char *b;
125 printf("%n", b); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
126 printf("%n", &x); // no-warning
127
128 printf("%hhn", (signed char*)0); // no-warning
129 printf("%hhn", (char*)0); // no-warning
130 printf("%hhn", (unsigned char*)0); // no-warning
131 printf("%hhn", (int*)0); // expected-warning{{format specifies type 'signed char *' but the argument has type 'int *'}}
132
133 printf("%hn", (short*)0); // no-warning
134 printf("%hn", (unsigned short*)0); // no-warning
135 printf("%hn", (int*)0); // expected-warning{{format specifies type 'short *' but the argument has type 'int *'}}
136
137 printf("%n", (int*)0); // no-warning
138 printf("%n", (unsigned int*)0); // no-warning
139 printf("%n", (char*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}
140
141 printf("%ln", (long*)0); // no-warning
142 printf("%ln", (unsigned long*)0); // no-warning
143 printf("%ln", (int*)0); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
144
145 printf("%lln", (long long*)0); // no-warning
146 printf("%lln", (unsigned long long*)0); // no-warning
147 printf("%lln", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
148
149 printf("%qn", (long long*)0); // no-warning
150 printf("%qn", (unsigned long long*)0); // no-warning
151 printf("%qn", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
152
153 printf("%Ln", 0); // expected-warning{{length modifier 'L' results in undefined behavior or no effect with 'n' conversion specifier}}
154 // expected-note@-1{{did you mean to use 'll'?}}
155 }
156
check_invalid_specifier(FILE * fp,char * buf)157 void check_invalid_specifier(FILE* fp, char *buf)
158 {
159 printf("%s%lb%d","unix",10,20); // expected-warning {{invalid conversion specifier 'b'}}
160 fprintf(fp,"%%%l"); // expected-warning {{incomplete format specifier}}
161 sprintf(buf,"%%%%%ld%d%d", 1, 2, 3); // expected-warning{{format specifies type 'long' but the argument has type 'int'}}
162 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 ';'}}
163 }
164
check_null_char_string(char * b)165 void check_null_char_string(char* b)
166 {
167 printf("\0this is bogus%d",1); // expected-warning {{string contains '\0'}}
168 snprintf(b,10,"%%%%%d\0%d",1,2); // expected-warning {{string contains '\0'}}
169 printf("%\0d",1); // expected-warning {{string contains '\0'}}
170 }
171
check_empty_format_string(char * buf,...)172 void check_empty_format_string(char* buf, ...)
173 {
174 va_list ap;
175 va_start(ap,buf);
176 vprintf("",ap); // expected-warning {{format string is empty}}
177 sprintf(buf, "", 1); // expected-warning {{format string is empty}}
178
179 // Don't warn about empty format strings when there are no data arguments.
180 // This can arise from macro expansions and non-standard format string
181 // functions.
182 sprintf(buf, ""); // no-warning
183 }
184
check_wide_string(char * b,...)185 void check_wide_string(char* b, ...)
186 {
187 va_list ap;
188 va_start(ap,b);
189
190 printf(L"foo %d",2); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
191 vsprintf(b,L"bar %d",ap); // expected-warning {{incompatible pointer types}}, expected-warning {{should not be a wide string}}
192 }
193
check_asterisk_precision_width(int x)194 void check_asterisk_precision_width(int x) {
195 printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
196 printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
197 printf("%*d",12,x); // no-warning
198 printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
199 printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
200 }
201
202 void __attribute__((format(printf,1,3))) myprintf(const char*, int blah, ...);
203
test_myprintf()204 void test_myprintf() {
205 myprintf("%d", 17, 18); // okay
206 }
207
test_constant_bindings(void)208 void test_constant_bindings(void) {
209 const char * const s1 = "hello";
210 const char s2[] = "hello";
211 const char *s3 = "hello";
212 char * const s4 = "hello";
213 extern const char s5[];
214
215 printf(s1); // no-warning
216 printf(s2); // no-warning
217 printf(s3); // expected-warning{{not a string literal}}
218 // expected-note@-1{{treat the string as an argument to avoid this}}
219 printf(s4); // expected-warning{{not a string literal}}
220 // expected-note@-1{{treat the string as an argument to avoid this}}
221 printf(s5); // expected-warning{{not a string literal}}
222 // expected-note@-1{{treat the string as an argument to avoid this}}
223 }
224
225
226 // Test what happens when -Wformat-security only.
227 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
228 #pragma GCC diagnostic warning "-Wformat-security"
229
test9(char * P)230 void test9(char *P) {
231 int x;
232 printf(P); // expected-warning {{format string is not a string literal (potentially insecure)}}
233 // expected-note@-1{{treat the string as an argument to avoid this}}
234 printf(P, 42);
235 }
236
torture(va_list v8)237 void torture(va_list v8) {
238 vprintf ("%*.*d", v8); // no-warning
239
240 }
241
test10(int x,float f,int i,long long lli)242 void test10(int x, float f, int i, long long lli) {
243 printf("%s"); // expected-warning{{more '%' conversions than data arguments}}
244 printf("%@", 12); // expected-warning{{invalid conversion specifier '@'}}
245 printf("\0"); // expected-warning{{format string contains '\0' within the string body}}
246 printf("xs\0"); // expected-warning{{format string contains '\0' within the string body}}
247 printf("%*d\n"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
248 printf("%*.*d\n", x); // expected-warning{{'.*' specified field precision is missing a matching 'int' argument}}
249 printf("%*d\n", f, x); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
250 printf("%*.*d\n", x, f, x); // expected-warning{{field precision should have type 'int', but argument has type 'double'}}
251 printf("%**\n"); // expected-warning{{invalid conversion specifier '*'}}
252 printf("%d%d\n", x); // expected-warning{{more '%' conversions than data arguments}}
253 printf("%d\n", x, x); // expected-warning{{data argument not used by format string}}
254 printf("%W%d\n", x, x); // expected-warning{{invalid conversion specifier 'W'}}
255 printf("%"); // expected-warning{{incomplete format specifier}}
256 printf("%.d", x); // no-warning
257 printf("%.", x); // expected-warning{{incomplete format specifier}}
258 printf("%f", 4); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
259 printf("%qd", lli); // no-warning
260 printf("%qd", x); // expected-warning{{format specifies type 'long long' but the argument has type 'int'}}
261 printf("%qp", (void *)0); // expected-warning{{length modifier 'q' results in undefined behavior or no effect with 'p' conversion specifier}}
262 printf("hhX %hhX", (unsigned char)10); // no-warning
263 printf("llX %llX", (long long) 10); // no-warning
264 // This is fine, because there is an implicit conversion to an int.
265 printf("%d", (unsigned char) 10); // no-warning
266 printf("%d", (long long) 10); // expected-warning{{format specifies type 'int' but the argument has type 'long long'}}
267 printf("%Lf\n", (long double) 1.0); // no-warning
268 printf("%f\n", (long double) 1.0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
269 // The man page says that a zero precision is okay.
270 printf("%.0Lf", (long double) 1.0); // no-warning
271 printf("%c\n", "x"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
272 printf("%c\n", 1.23); // expected-warning{{format specifies type 'int' but the argument has type 'double'}}
273 printf("Format %d, is %! %f", 1, 2, 4.4); // expected-warning{{invalid conversion specifier '!'}}
274 }
275
276 typedef unsigned char uint8_t;
277
should_understand_small_integers()278 void should_understand_small_integers() {
279 printf("%hhu", (short) 10); // expected-warning{{format specifies type 'unsigned char' but the argument has type 'short'}}
280 printf("%hu\n", (unsigned char) 1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'unsigned char'}}
281 printf("%hu\n", (uint8_t)1); // expected-warning{{format specifies type 'unsigned short' but the argument has type 'uint8_t'}}
282 }
283
test11(void * p,char * s)284 void test11(void *p, char *s) {
285 printf("%p", p); // no-warning
286 printf("%p", 123); // expected-warning{{format specifies type 'void *' but the argument has type 'int'}}
287 printf("%.4p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
288 printf("%+p", p); // expected-warning{{flag '+' results in undefined behavior with 'p' conversion specifier}}
289 printf("% p", p); // expected-warning{{flag ' ' results in undefined behavior with 'p' conversion specifier}}
290 printf("%0p", p); // expected-warning{{flag '0' results in undefined behavior with 'p' conversion specifier}}
291 printf("%s", s); // no-warning
292 printf("%+s", p); // expected-warning{{flag '+' results in undefined behavior with 's' conversion specifier}}
293 printf("% s", p); // expected-warning{{flag ' ' results in undefined behavior with 's' conversion specifier}}
294 printf("%0s", p); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
295 }
296
test12(char * b)297 void test12(char *b) {
298 unsigned char buf[4];
299 printf ("%.4s\n", buf); // no-warning
300 printf ("%.4s\n", &buf); // expected-warning{{format specifies type 'char *' but the argument has type 'unsigned char (*)[4]'}}
301
302 // Verify that we are checking asprintf
303 asprintf(&b, "%d", "asprintf"); // expected-warning{{format specifies type 'int' but the argument has type 'char *'}}
304 }
305
test13(short x)306 void test13(short x) {
307 char bel = 007;
308 printf("bel: '0%hhd'\n", bel); // no-warning
309 printf("x: '0%hhd'\n", x); // expected-warning {{format specifies type 'char' but the argument has type 'short'}}
310 }
311
312 typedef struct __aslclient *aslclient;
313 typedef struct __aslmsg *aslmsg;
314 int asl_log(aslclient asl, aslmsg msg, int level, const char *format, ...) __attribute__((__format__ (__printf__, 4, 5)));
test_asl(aslclient asl)315 void test_asl(aslclient asl) {
316 // Test case from <rdar://problem/7341605>.
317 asl_log(asl, 0, 3, "Error: %m"); // no-warning
318 asl_log(asl, 0, 3, "Error: %W"); // expected-warning{{invalid conversion specifier 'W'}}
319 }
320
321 // <rdar://problem/7595366>
322 typedef enum { A } int_t;
f0(int_t x)323 void f0(int_t x) { printf("%d\n", x); }
324
325 // Unicode test cases. These are possibly specific to Mac OS X. If so, they should
326 // eventually be moved into a separate test.
327
test_unicode_conversions(wchar_t * s)328 void test_unicode_conversions(wchar_t *s) {
329 printf("%S", s); // no-warning
330 printf("%s", s); // expected-warning{{format specifies type 'char *' but the argument has type 'wchar_t *'}}
331 printf("%C", s[0]); // no-warning
332 printf("%c", s[0]);
333 // FIXME: This test reports inconsistent results. On Windows, '%C' expects
334 // 'unsigned short'.
335 // printf("%C", 10);
336 printf("%S", "hello"); // expected-warning{{but the argument has type 'char *'}}
337 }
338
339 // Mac OS X supports positional arguments in format strings.
340 // This is an IEEE extension (IEEE Std 1003.1).
341 // FIXME: This is probably not portable everywhere.
test_positional_arguments()342 void test_positional_arguments() {
343 printf("%0$", (int)2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
344 printf("%1$*0$d", (int) 2); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
345 printf("%1$d", (int) 2); // no-warning
346 printf("%1$d", (int) 2, 2); // expected-warning{{data argument not used by format string}}
347 printf("%1$d%1$f", (int) 2); // expected-warning{{format specifies type 'double' but the argument has type 'int'}}
348 printf("%1$2.2d", (int) 2); // no-warning
349 printf("%2$*1$.2d", (int) 2, (int) 3); // no-warning
350 printf("%2$*8$d", (int) 2, (int) 3); // expected-warning{{specified field width is missing a matching 'int' argument}}
351 printf("%%%1$d", (int) 2); // no-warning
352 printf("%1$d%%", (int) 2); // no-warning
353 }
354
355 // PR 6697 - Handle format strings where the data argument is not adjacent to the format string
356 void myprintf_PR_6697(const char *format, int x, ...) __attribute__((__format__(printf,1, 3)));
test_pr_6697()357 void test_pr_6697() {
358 myprintf_PR_6697("%s\n", 1, "foo"); // no-warning
359 myprintf_PR_6697("%s\n", 1, (int)0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
360 // FIXME: Not everything should clearly support positional arguments,
361 // but we need a way to identify those cases.
362 myprintf_PR_6697("%1$s\n", 1, "foo"); // no-warning
363 myprintf_PR_6697("%2$s\n", 1, "foo"); // expected-warning{{data argument position '2' exceeds the number of data arguments (1)}}
364 myprintf_PR_6697("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (1)}}
365 myprintf_PR_6697("%1$s\n", 1, (int) 0); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
366 }
367
rdar8026030(FILE * fp)368 void rdar8026030(FILE *fp) {
369 fprintf(fp, "\%"); // expected-warning{{incomplete format specifier}}
370 }
371
bug7377_bad_length_mod_usage()372 void bug7377_bad_length_mod_usage() {
373 // Bad length modifiers
374 printf("%hhs", "foo"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
375 printf("%1$zp", (void *)0); // expected-warning{{length modifier 'z' results in undefined behavior or no effect with 'p' conversion specifier}}
376 printf("%ls", L"foo"); // no-warning
377 printf("%#.2Lf", (long double)1.234); // no-warning
378
379 // Bad flag usage
380 printf("%#p", (void *) 0); // expected-warning{{flag '#' results in undefined behavior with 'p' conversion specifier}}
381 printf("%0d", -1); // no-warning
382 printf("%#n", (int *) 0); // expected-warning{{flag '#' results in undefined behavior with 'n' conversion specifier}}
383 printf("%-n", (int *) 0); // expected-warning{{flag '-' results in undefined behavior with 'n' conversion specifier}}
384 printf("%-p", (void *) 0); // no-warning
385
386 // Bad optional amount use
387 printf("%.2c", 'a'); // expected-warning{{precision used with 'c' conversion specifier, resulting in undefined behavior}}
388 printf("%1n", (int *) 0); // expected-warning{{field width used with 'n' conversion specifier, resulting in undefined behavior}}
389 printf("%.9n", (int *) 0); // expected-warning{{precision used with 'n' conversion specifier, resulting in undefined behavior}}
390
391 // Ignored flags
392 printf("% +f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
393 printf("%+ f", 1.23); // expected-warning{{flag ' ' is ignored when flag '+' is present}}
394 printf("%0-f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
395 printf("%-0f", 1.23); // expected-warning{{flag '0' is ignored when flag '-' is present}}
396 printf("%-+f", 1.23); // no-warning
397 }
398
399 // PR 7981 - handle '%lc' (wint_t)
400
pr7981(wint_t c,wchar_t c2)401 void pr7981(wint_t c, wchar_t c2) {
402 printf("%lc", c); // no-warning
403 printf("%lc", 1.0); // expected-warning{{the argument has type 'double'}}
404 printf("%lc", (char) 1); // no-warning
405 printf("%lc", &c); // expected-warning{{the argument has type 'wint_t *'}}
406 // If wint_t and wchar_t are the same width and wint_t is signed where
407 // wchar_t is unsigned, an implicit conversion isn't possible.
408 #if defined(__WINT_UNSIGNED__) || !defined(__WCHAR_UNSIGNED__) || \
409 __WINT_WIDTH__ > __WCHAR_WIDTH__
410 printf("%lc", c2); // no-warning
411 #endif
412 }
413
414 // <rdar://problem/8269537> -Wformat-security says NULL is not a string literal
rdar8269537()415 void rdar8269537() {
416 // This is likely to crash in most cases, but -Wformat-nonliteral technically
417 // doesn't warn in this case.
418 printf(0); // no-warning
419 }
420
421 // Handle functions with multiple format attributes.
422 extern void rdar8332221_vprintf_scanf(const char *, va_list, const char *, ...)
423 __attribute__((__format__(__printf__, 1, 0)))
424 __attribute__((__format__(__scanf__, 3, 4)));
425
rdar8332221(va_list ap,int * x,long * y)426 void rdar8332221(va_list ap, int *x, long *y) {
427 rdar8332221_vprintf_scanf("%", ap, "%d", x); // expected-warning{{incomplete format specifier}}
428 }
429
430 // PR8641
pr8641()431 void pr8641() {
432 printf("%#x\n", 10);
433 printf("%#X\n", 10);
434 }
435
posix_extensions()436 void posix_extensions() {
437 // Test %'d, "thousands grouping".
438 // <rdar://problem/8816343>
439 printf("%'d\n", 123456789); // no-warning
440 printf("%'i\n", 123456789); // no-warning
441 printf("%'f\n", (float) 1.0); // no-warning
442 printf("%'p\n", (void*) 0); // expected-warning{{results in undefined behavior with 'p' conversion specifier}}
443 }
444
445 // PR8486
446 //
447 // Test what happens when -Wformat is on, but -Wformat-security is off.
448 #pragma GCC diagnostic warning "-Wformat"
449 #pragma GCC diagnostic ignored "-Wformat-security"
450
pr8486()451 void pr8486() {
452 printf("%s", 1); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
453 }
454
455 // PR9314
456 // Don't warn about string literals that are PreDefinedExprs, e.g. __func__.
pr9314()457 void pr9314() {
458 printf(__PRETTY_FUNCTION__); // no-warning
459 printf(__func__); // no-warning
460 }
461
462 int printf(const char * restrict, ...) __attribute__((__format__ (__printf__, 1, 2)));
463
rdar9612060(void)464 void rdar9612060(void) {
465 printf("%s", 2); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
466 }
467
check_char(unsigned char x,signed char y)468 void check_char(unsigned char x, signed char y) {
469 printf("%c", y); // no-warning
470 printf("%hhu", x); // no-warning
471 printf("%hhi", y); // no-warning
472 printf("%hhi", x); // no-warning
473 printf("%c", x); // no-warning
474 printf("%hhu", y); // no-warning
475 }
476
477 // Test suppression of individual warnings.
478
test_suppress_invalid_specifier()479 void test_suppress_invalid_specifier() {
480 #pragma clang diagnostic push
481 #pragma clang diagnostic ignored "-Wformat-invalid-specifier"
482 printf("%@", 12); // no-warning
483 #pragma clang diagnostic pop
484 }
485
486 // Make sure warnings are on for next test.
487 #pragma GCC diagnostic warning "-Wformat"
488 #pragma GCC diagnostic warning "-Wformat-security"
489
490 // Test that the printf call site is where the warning is attached. If the
491 // format string is somewhere else, point to it in a note.
pr9751()492 void pr9751() {
493 const char kFormat1[] = "%d %d \n"; // expected-note{{format string is defined here}}}
494 printf(kFormat1, 0); // expected-warning{{more '%' conversions than data arguments}}
495 printf("%d %s\n", 0); // expected-warning{{more '%' conversions than data arguments}}
496
497 const char kFormat2[] = "%18$s\n"; // expected-note{{format string is defined here}}
498 printf(kFormat2, 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
499 printf("%18$s\n", 1, "foo"); // expected-warning{{data argument position '18' exceeds the number of data arguments (2)}}
500
501 const char kFormat4[] = "%y"; // expected-note{{format string is defined here}}
502 printf(kFormat4, 5); // expected-warning{{invalid conversion specifier 'y'}}
503 printf("%y", 5); // expected-warning{{invalid conversion specifier 'y'}}
504
505 const char kFormat5[] = "%."; // expected-note{{format string is defined here}}
506 printf(kFormat5, 5); // expected-warning{{incomplete format specifier}}
507 printf("%.", 5); // expected-warning{{incomplete format specifier}}
508
509 const char kFormat6[] = "%s"; // expected-note{{format string is defined here}}
510 printf(kFormat6, 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
511 printf("%s", 5); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
512
513 const char kFormat7[] = "%0$"; // expected-note{{format string is defined here}}
514 printf(kFormat7, 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
515 printf("%0$", 5); // expected-warning{{position arguments in format strings start counting at 1 (not 0)}}
516
517 const char kFormat8[] = "%1$d %d"; // expected-note{{format string is defined here}}
518 printf(kFormat8, 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
519 printf("%1$d %d", 4, 4); // expected-warning{{cannot mix positional and non-positional arguments in format string}}
520
521 const char kFormat9[] = ""; // expected-note{{format string is defined here}}
522 printf(kFormat9, 4, 4); // expected-warning{{format string is empty}}
523 printf("", 4, 4); // expected-warning{{format string is empty}}
524
525 const char kFormat10[] = "\0%d"; // expected-note{{format string is defined here}}
526 printf(kFormat10, 4); // expected-warning{{format string contains '\0' within the string body}}
527 printf("\0%d", 4); // expected-warning{{format string contains '\0' within the string body}}
528
529 const char kFormat11[] = "%*d"; // expected-note{{format string is defined here}}
530 printf(kFormat11); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
531 printf("%*d"); // expected-warning{{'*' specified field width is missing a matching 'int' argument}}
532
533 const char kFormat12[] = "%*d"; // expected-note{{format string is defined here}}
534 printf(kFormat12, 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
535 printf("%*d", 4.4); // expected-warning{{field width should have type 'int', but argument has type 'double'}}
536
537 const char kFormat13[] = "%.3p"; // expected-note{{format string is defined here}}
538 void *p;
539 printf(kFormat13, p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
540 printf("%.3p", p); // expected-warning{{precision used with 'p' conversion specifier, resulting in undefined behavior}}
541
542 const char kFormat14[] = "%0s"; // expected-note{{format string is defined here}}
543 printf(kFormat14, "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
544 printf("%0s", "a"); // expected-warning{{flag '0' results in undefined behavior with 's' conversion specifier}}
545
546 const char kFormat15[] = "%hhs"; // expected-note{{format string is defined here}}
547 printf(kFormat15, "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
548 printf("%hhs", "a"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
549
550 const char kFormat16[] = "%-0d"; // expected-note{{format string is defined here}}
551 printf(kFormat16, 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
552 printf("%-0d", 5); // expected-warning{{flag '0' is ignored when flag '-' is present}}
553
554 // Make sure that the "format string is defined here" note is not emitted
555 // when the original string is within the argument expression.
556 printf(1 ? "yes %d" : "no %d"); // expected-warning{{more '%' conversions than data arguments}}
557
558 const char kFormat17[] = "%hu"; // expected-note{{format string is defined here}}}
559 printf(kFormat17, (int[]){0}); // expected-warning{{format specifies type 'unsigned short' but the argument}}
560
561 printf("%a", (long double)0); // expected-warning{{format specifies type 'double' but the argument has type 'long double'}}
562
563 // Test braced char[] initializers.
564 const char kFormat18[] = { "%lld" }; // expected-note{{format string is defined here}}
565 printf(kFormat18, 0); // expected-warning{{format specifies type}}
566
567 // Make sure we point at the offending argument rather than the format string.
568 const char kFormat19[] = "%d"; // expected-note{{format string is defined here}}
569 printf(kFormat19,
570 0.0); // expected-warning{{format specifies}}
571 }
572
pr18905()573 void pr18905() {
574 const char s1[] = "s\0%s"; // expected-note{{format string is defined here}}
575 const char s2[1] = "s"; // expected-note{{format string is defined here}}
576 const char s3[2] = "s\0%s"; // expected-warning{{initializer-string for char array is too long}}
577 const char s4[10] = "s";
578 const char s5[0] = "%s"; // expected-warning{{initializer-string for char array is too long}}
579 // expected-note@-1{{format string is defined here}}
580
581 printf(s1); // expected-warning{{format string contains '\0' within the string body}}
582 printf(s2); // expected-warning{{format string is not null-terminated}}
583 printf(s3); // no-warning
584 printf(s4); // no-warning
585 printf(s5); // expected-warning{{format string is not null-terminated}}
586 }
587
588 void __attribute__((format(strfmon,1,2))) monformat(const char *fmt, ...);
589 void __attribute__((format(strftime,1,0))) dateformat(const char *fmt);
590
591 // Other formats
test_other_formats()592 void test_other_formats() {
593 char *str = "";
594 monformat("", 1); // expected-warning{{format string is empty}}
595 monformat(str); // expected-warning{{format string is not a string literal (potentially insecure)}}
596 dateformat(""); // expected-warning{{format string is empty}}
597 dateformat(str); // no-warning (using strftime non-literal is not unsafe)
598 }
599
600 // Do not warn about unused arguments coming from system headers.
601 // <rdar://problem/11317765>
602 #include <format-unused-system-args.h>
test_unused_system_args(int x)603 void test_unused_system_args(int x) {
604 PRINT1("%d\n", x); // no-warning{{extra argument is system header is OK}}
605 }
606
pr12761(char c)607 void pr12761(char c) {
608 // This should not warn even with -fno-signed-char.
609 printf("%hhx", c);
610 }
611
612
613 // Test that we correctly merge the format in both orders.
614 extern void test14_foo(const char *, const char *, ...)
615 __attribute__((__format__(__printf__, 1, 3)));
616 extern void test14_foo(const char *, const char *, ...)
617 __attribute__((__format__(__scanf__, 2, 3)));
618
619 extern void test14_bar(const char *, const char *, ...)
620 __attribute__((__format__(__scanf__, 2, 3)));
621 extern void test14_bar(const char *, const char *, ...)
622 __attribute__((__format__(__printf__, 1, 3)));
623
test14_zed(int * p)624 void test14_zed(int *p) {
625 test14_foo("%", "%d", p); // expected-warning{{incomplete format specifier}}
626 test14_bar("%", "%d", p); // expected-warning{{incomplete format specifier}}
627 }
628
test_qualifiers(volatile int * vip,const int * cip,const volatile int * cvip)629 void test_qualifiers(volatile int *vip, const int *cip,
630 const volatile int *cvip) {
631 printf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
632 printf("%n", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}
633
634 printf("%n", vip); // No warning.
635 printf("%p", cip); // No warning.
636 printf("%p", cvip); // No warning.
637
638
639 typedef int* ip_t;
640 typedef const int* cip_t;
641 printf("%n", (ip_t)0); // No warning.
642 printf("%n", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
643 }
644
645 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
646 #pragma GCC diagnostic warning "-Wformat-security"
647 // <rdar://problem/14178260>
648 extern void test_format_security_extra_args(const char*, int, ...)
649 __attribute__((__format__(__printf__, 1, 3)));
test_format_security_pos(char * string)650 void test_format_security_pos(char* string) {
651 test_format_security_extra_args(string, 5); // expected-warning {{format string is not a string literal (potentially insecure)}}
652 // expected-note@-1{{treat the string as an argument to avoid this}}
653 }
654 #pragma GCC diagnostic warning "-Wformat-nonliteral"
655