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stdio: Remove __libc_message alloca usage

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Use a fixed size array instead.  The maximum number of arguments
is set by macro tricks.
This commit is contained in:
Joe Simmons-Talbott 2023-08-31 16:20:59 -04:00 committed by Adhemerval Zanella
parent d3c34a2dd9
commit 742b35228f
2 changed files with 40 additions and 35 deletions
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28
include/stdio.h
View File

@ -172,10 +172,36 @@ extern int __gen_tempname (char *__tmpl, int __suffixlen, int __flags,
and abort. */
extern void __libc_fatal (const char *__message)
__attribute__ ((__noreturn__));
_Noreturn void __libc_message (const char *__fnt, ...) attribute_hidden;
extern void __fortify_fail (const char *msg) __attribute__ ((__noreturn__));
libc_hidden_proto (__fortify_fail)
/* The maximum number of varargs allowed in a __libc_message format string */
#define LIBC_MESSAGE_MAX_ARGS 4
_Noreturn void __libc_message_impl (const char *__fnt, ...) attribute_hidden;
#define __libc_message0(fmt) \
__libc_message_impl (fmt)
#define __libc_message1(fmt, a1) \
__libc_message_impl (fmt, a1)
#define __libc_message2(fmt, a1, a2) \
__libc_message_impl (fmt, a1, a2)
#define __libc_message3(fmt, a1, a2, a3) \
__libc_message_impl (fmt, a1, a2, a3)
#define __libc_message4(fmt, a1, a2, a3, a4) \
__libc_message_impl (fmt, a1, a2, a3, a4)
#define __libc_message_concat_x(a,b) a##b
#define __libc_message_concat(a,b) __libc_message_concat_x (a, b)
#define __libc_message_nargs_x(a0,a1,a2,a3,a4,a5,a6,...) a6
#define __libc_message_nargs(b, ...) \
__libc_message_nargs_x (__VA_ARGS__,6,5,4,3,2,1,0,)
#define __libc_message_disp(b, ...) \
__libc_message_concat (b, __libc_message_nargs (__VA_ARGS__))(__VA_ARGS__)
#define __libc_message(...) \
__libc_message_disp (__libc_message, __VA_ARGS__)
/* Acquire ownership of STREAM. */
extern void __flockfile (FILE *__stream) attribute_hidden;

47
sysdeps/posix/libc_fatal.c
View File

@ -45,22 +45,13 @@ writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total)
}
#endif
struct str_list
{
const char *str;
size_t len;
struct str_list *next;
};
/* Abort with an error message. */
void
__libc_message (const char *fmt, ...)
__libc_message_impl (const char *fmt, ...)
{
va_list ap;
int fd = -1;
va_start (ap, fmt);
#ifdef FATAL_PREPARE
FATAL_PREPARE;
#endif
@ -68,9 +59,11 @@ __libc_message (const char *fmt, ...)
if (fd == -1)
fd = STDERR_FILENO;
struct str_list *list = NULL;
int nlist = 0;
struct iovec iov[LIBC_MESSAGE_MAX_ARGS];
int iovcnt = 0;
ssize_t total = 0;
va_start (ap, fmt);
const char *cp = fmt;
while (*cp != '\0')
{
@ -100,28 +93,16 @@ __libc_message (const char *fmt, ...)
cp = next;
}
struct str_list *newp = alloca (sizeof (struct str_list));
newp->str = str;
newp->len = len;
newp->next = list;
list = newp;
++nlist;
iov[iovcnt].iov_base = (char *) str;
iov[iovcnt].iov_len = len;
total += len;
iovcnt++;
}
va_end (ap);
if (nlist > 0)
if (iovcnt > 0)
{
struct iovec *iov = alloca (nlist * sizeof (struct iovec));
ssize_t total = 0;
for (int cnt = nlist - 1; cnt >= 0; --cnt)
{
iov[cnt].iov_base = (char *) list->str;
iov[cnt].iov_len = list->len;
total += list->len;
list = list->next;
}
WRITEV_FOR_FATAL (fd, iov, nlist, total);
WRITEV_FOR_FATAL (fd, iov, iovcnt, total);
total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
struct abort_msg_s *buf = __mmap (NULL, total,
@ -131,7 +112,7 @@ __libc_message (const char *fmt, ...)
{
buf->size = total;
char *wp = buf->msg;
for (int cnt = 0; cnt < nlist; ++cnt)
for (int cnt = 0; cnt < iovcnt; ++cnt)
wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
*wp = '\0';
@ -144,8 +125,6 @@ __libc_message (const char *fmt, ...)
}
}
va_end (ap);
/* Kill the application. */
abort ();
}