@@ -17,6 +17,10 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
+#include <string.h>
+#if BUILD_PIE_DEFAULT
+# pragma GCC visibility push(hidden)
+#endif
#include <_itoa.h>
#include <assert.h>
#include <dl-writev.h>
@@ -25,11 +29,19 @@
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
-#include <string.h>
#include <sys/uio.h>
#include <unistd.h>
#include <intprops.h>
+/* The function might be called before the process is self-relocated. */
+static size_t
+_dl_debug_strlen (const char *s)
+{
+ const char *p = s;
+ for (; *s != '\0'; s++);
+ return s - p;
+}
+
/* Bare-bones printf implementation. This function only knows about
the formats and flags needed and can handle only up to 64 stripes in
the output. */
@@ -193,7 +205,7 @@ _dl_debug_vdprintf (int fd, int tag_p, const char *fmt, va_list arg)
case 's':
/* Get the string argument. */
iov[niov].iov_base = va_arg (arg, char *);
- iov[niov].iov_len = strlen (iov[niov].iov_base);
+ iov[niov].iov_len = _dl_debug_strlen (iov[niov].iov_base);
if (prec != -1)
iov[niov].iov_len = MIN ((size_t) prec, iov[niov].iov_len);
++niov;
@@ -460,6 +460,11 @@ CFLAGS-isoc23_scanf.c += -fexceptions
CFLAGS-dprintf.c += $(config-cflags-wno-ignored-attributes)
+# Called during static library initialization, so turn stack-protection
+# off for non-shared builds.
+CFLAGS-_itoa.o = $(no-stack-protector)
+CFLAGS-_itoa.op = $(no-stack-protector)
+
# scanf18.c and scanf19.c test a deprecated extension which is no
# longer visible under most conformance levels; see the source files
# for more detail.
@@ -16,6 +16,11 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
+/* Mark symbols hidden in static PIE for early self relocation to work.
+ Note: string.h may have ifuncs which cannot be hidden on i686. */
+#if BUILD_PIE_DEFAULT
+# pragma GCC visibility push(hidden)
+#endif
#include <gmp-mparam.h>
#include <gmp.h>
#include <limits.h>
new file mode 100644
@@ -0,0 +1,24 @@
+/* Message-writing for the dynamic linker. Linux/i386 version.
+ Copyright (C) 2013-2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#if BUILD_PIE_DEFAULT
+/* Can't use "call *%gs:SYSINFO_OFFSET" during startup in static PIE. */
+# define I386_USE_SYSENTER 0
+#endif
+
+#include <sysdeps/unix/sysv/linux/dl-writev.h>
The strlen might trigger and invalid GOT entry if it used before the process is self-relocated (for instance on dl-tunables if any error occurs). For i386, _dl_writev with PIE requires to use the old 'int $0x80' syscall mode because the calling the TLS register (gs) is not yet initialized. Checked on x86_64-linux-gnu. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org> --- elf/dl-printf.c | 16 ++++++++++++++-- stdio-common/Makefile | 5 +++++ stdio-common/_itoa.c | 5 +++++ sysdeps/unix/sysv/linux/i386/dl-writev.h | 24 ++++++++++++++++++++++++ 4 files changed, 48 insertions(+), 2 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/i386/dl-writev.h