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-rw-r--r--libio/iovsprintf.c54
1 files changed, 49 insertions, 5 deletions
diff --git a/libio/iovsprintf.c b/libio/iovsprintf.c
index cf4b9973a73..513ca030131 100644
--- a/libio/iovsprintf.c
+++ b/libio/iovsprintf.c
@@ -27,8 +27,47 @@
#include "libioP.h"
#include "strfile.h"
+static int __THROW
+_IO_str_chk_overflow (FILE *fp, int c)
+{
+ /* If we get here, the user-supplied buffer would be overrun by
+ further output. */
+ __chk_fail ();
+}
+
+static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable =
+{
+ JUMP_INIT_DUMMY,
+ JUMP_INIT(finish, _IO_str_finish),
+ JUMP_INIT(overflow, _IO_str_chk_overflow),
+ JUMP_INIT(underflow, _IO_str_underflow),
+ JUMP_INIT(uflow, _IO_default_uflow),
+ JUMP_INIT(pbackfail, _IO_str_pbackfail),
+ JUMP_INIT(xsputn, _IO_default_xsputn),
+ JUMP_INIT(xsgetn, _IO_default_xsgetn),
+ JUMP_INIT(seekoff, _IO_str_seekoff),
+ JUMP_INIT(seekpos, _IO_default_seekpos),
+ JUMP_INIT(setbuf, _IO_default_setbuf),
+ JUMP_INIT(sync, _IO_default_sync),
+ JUMP_INIT(doallocate, _IO_default_doallocate),
+ JUMP_INIT(read, _IO_default_read),
+ JUMP_INIT(write, _IO_default_write),
+ JUMP_INIT(seek, _IO_default_seek),
+ JUMP_INIT(close, _IO_default_close),
+ JUMP_INIT(stat, _IO_default_stat),
+ JUMP_INIT(showmanyc, _IO_default_showmanyc),
+ JUMP_INIT(imbue, _IO_default_imbue)
+};
+
+/* This function is called by regular vsprintf with maxlen set to -1,
+ and by vsprintf_chk with maxlen set to the size of the output
+ string. In the former case, _IO_str_chk_overflow will never be
+ called; in the latter case it will crash the program if the buffer
+ overflows. */
+
int
-__vsprintf_internal (char *string, const char *format, va_list args,
+__vsprintf_internal (char *string, size_t maxlen,
+ const char *format, va_list args,
unsigned int mode_flags)
{
_IO_strfile sf;
@@ -38,17 +77,22 @@ __vsprintf_internal (char *string, const char *format, va_list args,
sf._sbf._f._lock = NULL;
#endif
_IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
- _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
- _IO_str_init_static_internal (&sf, string, -1, string);
+ _IO_JUMPS (&sf._sbf) = &_IO_str_chk_jumps;
+ string[0] = '\0';
+ _IO_str_init_static_internal (&sf, string,
+ (maxlen == -1) ? -1 : maxlen - 1,
+ string);
+
ret = __vfprintf_internal (&sf._sbf._f, format, args, mode_flags);
- _IO_putc_unlocked ('\0', &sf._sbf._f);
+
+ *sf._sbf._f._IO_write_ptr = '\0';
return ret;
}
int
__vsprintf (char *string, const char *format, va_list args)
{
- return __vsprintf_internal (string, format, args, 0);
+ return __vsprintf_internal (string, -1, format, args, 0);
}
ldbl_strong_alias (__vsprintf, _IO_vsprintf)