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glibc  2.9
vsnprintf_chk.c File Reference
#include <stdarg.h>
#include <stdio.h>
#include "../libio/libioP.h"
#include "../libio/strfile.h"

Go to the source code of this file.


int ___vsnprintf_chk (char *s, size_t maxlen, int flags, size_t slen, const char *format, va_list args)

Function Documentation

int ___vsnprintf_chk ( char *  s,
size_t  maxlen,
int  flags,
size_t  slen,
const char *  format,
va_list  args 

Definition at line 31 of file vsnprintf_chk.c.

  /* XXX Maybe for less strict version do not fail immediately.
     Though, maxlen is supposed to be the size of buffer pointed
     to by s, so a conforming program can't pass such maxlen
     to *snprintf.  */
  if (__builtin_expect (slen < maxlen, 0))
    __chk_fail ();

  _IO_strnfile sf;
  int ret;
#ifdef _IO_MTSAFE_IO
  sf.f._sbf._f._lock = NULL;

  /* We need to handle the special case where MAXLEN is 0.  Use the
     overflow buffer right from the start.  */
  if (maxlen == 0)
      s = sf.overflow_buf;
      maxlen = sizeof (sf.overflow_buf);

  _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
  _IO_JUMPS ((struct _IO_FILE_plus *) &sf.f._sbf) = &_IO_strn_jumps;
  s[0] = '\0';

  /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
     can only come from read-only format strings.  */
  if (flags > 0)
    sf.f._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;

  _IO_str_init_static_internal (&sf.f, s, maxlen - 1, s);
  ret = INTUSE(_IO_vfprintf) ((_IO_FILE *) &sf.f._sbf, format, args);

  if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf)
    *sf.f._sbf._f._IO_write_ptr = '\0';
  return ret;

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