test/Sema/format-strings-scanf.c

// RUN: %clang_cc1 -fsyntax-only -verify -Wformat-nonliteral %s

// Test that -Wformat=0 works:
// RUN: %clang_cc1 -fsyntax-only -Werror -Wformat=0 %s

#include <stdarg.h>
typedef __typeof(sizeof(int)) size_t;
typedef struct _FILE FILE;
typedef __WCHAR_TYPE__ wchar_t;

int fscanf(FILE * restrict, const char * restrict, ...) ;
int scanf(const char * restrict, ...) ;
int sscanf(const char * restrict, const char * restrict, ...) ;
int my_scanf(const char * restrict, ...) __attribute__((__format__(__scanf__, 1, 2)));

int vscanf(const char * restrict, va_list);
int vfscanf(FILE * restrict, const char * restrict, va_list);
int vsscanf(const char * restrict, const char * restrict, va_list);

void test(const char *s, int *i) {
  scanf(s, i); // expected-warning{{ormat string is not a string literal}}
  scanf("%0d", i); // expected-warning{{zero field width in scanf format string is unused}}
  scanf("%00d", i); // expected-warning{{zero field width in scanf format string is unused}}
  scanf("%d%[asdfasdfd", i, s); // expected-warning{{no closing ']' for '%[' in scanf format string}}

  unsigned short s_x;
  scanf ("%" "hu" "\n", &s_x); // no-warning
  scanf("%y", i); // expected-warning{{invalid conversion specifier 'y'}}
  scanf("%%"); // no-warning
  scanf("%%%1$d", i); // no-warning
  scanf("%1$d%%", i); // no-warning
  scanf("%d", i, i); // expected-warning{{data argument not used by format string}}
  scanf("%*d", i); // // expected-warning{{data argument not used by format string}}
  scanf("%*d", i); // // expected-warning{{data argument not used by format string}}
  scanf("%*d%1$d", i); // no-warning

  scanf("%s", (char*)0); // no-warning
  scanf("%s", (volatile char*)0); // no-warning
  scanf("%s", (signed char*)0); // no-warning
  scanf("%s", (unsigned char*)0); // no-warning
  scanf("%hhu", (signed char*)0); // no-warning
}

void bad_length_modifiers(char *s, void *p, wchar_t *ws, long double *ld) {
  scanf("%hhs", "foo"); // expected-warning{{length modifier 'hh' results in undefined behavior or no effect with 's' conversion specifier}}
  scanf("%1$zp", &p); // expected-warning{{length modifier 'z' results in undefined behavior or no effect with 'p' conversion specifier}}
  scanf("%ls", ws); // no-warning
  scanf("%#.2Lf", ld); // expected-warning{{invalid conversion specifier '#'}}
}

// Test that the scanf call site is where the warning is attached.  If the
// format string is somewhere else, point to it in a note.
void pr9751() {
  int *i;
  char str[100];
  const char kFormat1[] = "%00d"; // expected-note{{format string is defined here}}}
  scanf(kFormat1, i); // expected-warning{{zero field width in scanf format string is unused}}
  scanf("%00d", i); // expected-warning{{zero field width in scanf format string is unused}}
  const char kFormat2[] = "%["; // expected-note{{format string is defined here}}}
  scanf(kFormat2, str); // expected-warning{{no closing ']' for '%[' in scanf format string}}
  scanf("%[", str); // expected-warning{{no closing ']' for '%[' in scanf format string}}
  const char kFormat3[] = "%hu"; // expected-note{{format string is defined here}}}
  scanf(kFormat3, &i); // expected-warning {{format specifies type 'unsigned short *' but the argument}}
  const char kFormat4[] = "%lp"; // expected-note{{format string is defined here}}}
  scanf(kFormat4, &i); // expected-warning {{length modifier 'l' results in undefined behavior or no effect with 'p' conversion specifier}}
}

void test_variants(int *i, const char *s, ...) {
  FILE *f = 0;
  char buf[100];

  fscanf(f, "%ld", i); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
  sscanf(buf, "%ld", i); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}
  my_scanf("%ld", i); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}

  va_list ap;
  va_start(ap, s);

  vscanf("%[abc", ap); // expected-warning{{no closing ']' for '%[' in scanf format string}}
  vfscanf(f, "%[abc", ap); // expected-warning{{no closing ']' for '%[' in scanf format string}}
  vsscanf(buf, "%[abc", ap); // expected-warning{{no closing ']' for '%[' in scanf format string}}
}

void test_scanlist(int *ip, char *sp, wchar_t *ls) {
  scanf("%[abc]", ip); // expected-warning{{format specifies type 'char *' but the argument has type 'int *'}}
  scanf("%h[abc]", sp); // expected-warning{{length modifier 'h' results in undefined behavior or no effect with '[' conversion specifier}}
  scanf("%l[xyx]", ls); // no-warning
  scanf("%ll[xyx]", ls); // expected-warning {{length modifier 'll' results in undefined behavior or no effect with '[' conversion specifier}}
}

void test_alloc_extension(char **sp, wchar_t **lsp, float *fp) {
  /* Make sure "%a" gets parsed as a conversion specifier for float,
   * even when followed by an 's', 'S' or '[', which would cause it to be
   * parsed as a length modifier in C90. */
  scanf("%as", sp); // expected-warning{{format specifies type 'float *' but the argument has type 'char **'}}
  scanf("%aS", lsp); // expected-warning{{format specifies type 'float *' but the argument has type 'wchar_t **'}}
  scanf("%a[bcd]", sp); // expected-warning{{format specifies type 'float *' but the argument has type 'char **'}}

  // Test that the 'm' length modifier is only allowed with s, S, c, C or [.
  // TODO: Warn that 'm' is an extension.
  scanf("%ms", sp); // No warning.
  scanf("%mS", lsp); // No warning.
  scanf("%mc", sp); // No warning.
  scanf("%mC", lsp); // No warning.
  scanf("%m[abc]", sp); // No warning.
  scanf("%md", sp); // expected-warning{{length modifier 'm' results in undefined behavior or no effect with 'd' conversion specifier}}

  // Test argument type check for the 'm' length modifier.
  scanf("%ms", fp); // expected-warning{{format specifies type 'char **' but the argument has type 'float *'}}
  scanf("%mS", fp); // expected-warning-re{{format specifies type 'wchar_t \*\*' \(aka '[^']+'\) but the argument has type 'float \*'}}
  scanf("%mc", fp); // expected-warning{{format specifies type 'char **' but the argument has type 'float *'}}
  scanf("%mC", fp); // expected-warning-re{{format specifies type 'wchar_t \*\*' \(aka '[^']+'\) but the argument has type 'float \*'}}
  scanf("%m[abc]", fp); // expected-warning{{format specifies type 'char **' but the argument has type 'float *'}}
}

void test_quad(int *x, long long *llx) {
  scanf("%qd", x); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}
  scanf("%qd", llx); // no-warning
}

void test_writeback(int *x) {
  scanf("%n", (void*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'void *'}}
  scanf("%n %c", x, x); // expected-warning{{format specifies type 'char *' but the argument has type 'int *'}}

  scanf("%hhn", (signed char*)0); // no-warning
  scanf("%hhn", (char*)0); // no-warning
  scanf("%hhn", (unsigned char*)0); // no-warning
  scanf("%hhn", (int*)0); // expected-warning{{format specifies type 'signed char *' but the argument has type 'int *'}}

  scanf("%hn", (short*)0); // no-warning
  scanf("%hn", (unsigned short*)0); // no-warning
  scanf("%hn", (int*)0); // expected-warning{{format specifies type 'short *' but the argument has type 'int *'}}

  scanf("%n", (int*)0); // no-warning
  scanf("%n", (unsigned int*)0); // no-warning
  scanf("%n", (char*)0); // expected-warning{{format specifies type 'int *' but the argument has type 'char *'}}

  scanf("%ln", (long*)0); // no-warning
  scanf("%ln", (unsigned long*)0); // no-warning
  scanf("%ln", (int*)0); // expected-warning{{format specifies type 'long *' but the argument has type 'int *'}}

  scanf("%lln", (long long*)0); // no-warning
  scanf("%lln", (unsigned long long*)0); // no-warning
  scanf("%lln", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}

  scanf("%qn", (long long*)0); // no-warning
  scanf("%qn", (unsigned long long*)0); // no-warning
  scanf("%qn", (int*)0); // expected-warning{{format specifies type 'long long *' but the argument has type 'int *'}}

}

void test_qualifiers(const int *cip, volatile int* vip,
                     const char *ccp, volatile char* vcp,
                     const volatile int *cvip) {
  scanf("%d", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
  scanf("%n", cip); // expected-warning{{format specifies type 'int *' but the argument has type 'const int *'}}
  scanf("%s", ccp); // expected-warning{{format specifies type 'char *' but the argument has type 'const char *'}}
  scanf("%d", cvip); // expected-warning{{format specifies type 'int *' but the argument has type 'const volatile int *'}}

  scanf("%d", vip); // No warning.
  scanf("%n", vip); // No warning.
  scanf("%c", vcp); // No warning.

  typedef int* ip_t;
  typedef const int* cip_t;
  scanf("%d", (ip_t)0); // No warning.
  scanf("%d", (cip_t)0); // expected-warning{{format specifies type 'int *' but the argument has type 'cip_t' (aka 'const int *')}}
}