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[PATCH v3 5/7] Add __vsyslog_internal, with same flags as __v*printf_internal.
- From: "Gabriel F. T. Gomes" <gabriel at inconstante dot eti dot br>
- To: <libc-alpha at sourceware dot org>
- Date: Thu, 15 Nov 2018 19:44:47 -0200
- Subject: [PATCH v3 5/7] Add __vsyslog_internal, with same flags as __v*printf_internal.
- References: <20181115214449.19262-1-gabriel@inconstante.eti.br>
From: Zack Weinberg <zackw@panix.com>
Changes since v2
- None, but dependent on previous patch in the set, thus resending.
Changed since v1:
- Fixed white-space errors.
- Removed internal declaration of __vsyslog_chk, because it's no
longer called from within libc. There's a call to it in the inline
definition of vsyslog in bits/syslog.h, but that definition is only
inlined in user code with:
#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
- Removed libc_hidden_def and libc_hidden_proto for vsyslog, as it is
never called internally (it never was).
- Added attribute_hidden to the internal declaration of
__vsyslog_internal. Here are the objdumps of one internal call,
before and after this change, on a 32-bits powerpc machine:
Without attribute_hidden:
$ objdump -d --reloc SYSLOG-PRISTINE-glibc/libc.so | grep "<vsyslog@@GLIBC_2.4>:" -A 17
000fc790 <vsyslog@@GLIBC_2.4>:
fc790: 94 21 ff f0 stwu r1,-16(r1)
fc794: 38 c0 00 00 li r6,0
fc798: 7c 08 02 a6 mflr r0
fc79c: 42 9f 00 05 bcl 20,4*cr7+so,fc7a0 <vsyslog@@GLIBC_2.4+0x10>
fc7a0: 93 c1 00 08 stw r30,8(r1)
fc7a4: 90 01 00 14 stw r0,20(r1)
fc7a8: 7f c8 02 a6 mflr r30
fc7ac: 3f de 00 0a addis r30,r30,10
fc7b0: 3b de 38 54 addi r30,r30,14420
fc7b4: 4b ff f9 9d bl fc150 <__vsyslog_internal>
fc7b8: 80 01 00 14 lwz r0,20(r1)
fc7bc: 83 c1 00 08 lwz r30,8(r1)
fc7c0: 38 21 00 10 addi r1,r1,16
fc7c4: 7c 08 03 a6 mtlr r0
fc7c8: 4e 80 00 20 blr
fc7cc: 60 00 00 00 nop
With attribute_hidden:
$ objdump -d --reloc SYSLOG-PATCHED-glibc/libc.so | grep "<vsyslog@@GLIBC_2.4>:" -A 5
000fc780 <vsyslog@@GLIBC_2.4>:
fc780: 38 c0 00 00 li r6,0
fc784: 4b ff f9 cc b fc150 <__vsyslog_internal>
fc788: 60 00 00 00 nop
fc78c: 60 00 00 00 nop
-- 8< --
__nldbl___vsyslog_chk will ultimately want to pass PRINTF_LDBL_IS_DBL
down to __vfprintf_internal *as well as* possibly setting PRINTF_FORTIFY.
To make that possible, we need a __vsyslog_internal that takes the
same flags as printf. The code in misc/syslog.c does also get a
little simpler.
Tested for powerpc and powerpc64le.
2018-10-16 Zack Weinberg <zackw@panix.com>
Gabriel F. T. Gomes <gabriel@inconstante.eti.br>
* misc/syslog.c: Include libioP.h, not iolibio.h.
(__vsyslog_internal): New function with the former body of
__vsyslog_chk; takes mode_flags argument same as
__v*printf_internal. Call __vfprintf_internal directly.
(__vsyslog_chk): Now a wrapper around __vsyslog_internal.
Remove libc_hidden_def.
(__syslog, __syslog_chk): Use __vsyslog_internal.
(__vsyslog): Move to just below __syslog. Use __vsyslog_internal.
* include/sys/syslog.h: Add multiple inclusion guard.
Add prototype for __vsyslog_internal.
Remove declaration and libc_hidden_proto for __vsyslog_chk.
* sysdeps/ieee754/ldbl-opt/nldbl-compat.c (__nldbl___vsyslog_chk):
Use __vsyslog_internal.
---
include/sys/syslog.h | 19 ++++++++++-------
misc/syslog.c | 36 +++++++++++++++++----------------
sysdeps/ieee754/ldbl-opt/nldbl-compat.c | 2 +-
3 files changed, 32 insertions(+), 25 deletions(-)
diff --git a/include/sys/syslog.h b/include/sys/syslog.h
index 3be3189ed1..89d3479ebc 100644
--- a/include/sys/syslog.h
+++ b/include/sys/syslog.h
@@ -1,11 +1,16 @@
+#ifndef _LIBC_SYS_SYSLOG_H
+#define _LIBC_SYS_SYSLOG_H 1
#include <misc/sys/syslog.h>
-
#ifndef _ISOMAC
+
libc_hidden_proto (syslog)
-libc_hidden_proto (vsyslog)
-extern void __vsyslog_chk (int __pri, int __flag, const char *__fmt,
- __gnuc_va_list __ap)
- __attribute__ ((__format__ (__printf__, 3, 0)));
-libc_hidden_proto (__vsyslog_chk)
-#endif
+/* __vsyslog_internal uses the same mode_flags bits as
+ __v*printf_internal; see libio/libioP.h. */
+extern void __vsyslog_internal (int pri, const char *fmt, __gnuc_va_list ap,
+ unsigned int mode_flags)
+ attribute_hidden
+ __attribute__ ((__format__ (__printf__, 2, 0)));
+
+#endif /* _ISOMAC */
+#endif /* syslog.h */
diff --git a/misc/syslog.c b/misc/syslog.c
index 644dbe80ec..3a15da41ce 100644
--- a/misc/syslog.c
+++ b/misc/syslog.c
@@ -53,7 +53,7 @@ static char sccsid[] = "@(#)syslog.c 8.4 (Berkeley) 3/18/94";
#include <stdarg.h>
-#include <libio/iolibio.h>
+#include <libio/libioP.h>
#include <math_ldbl_opt.h>
#include <kernel-features.h>
@@ -114,24 +114,38 @@ __syslog(int pri, const char *fmt, ...)
va_list ap;
va_start(ap, fmt);
- __vsyslog_chk(pri, -1, fmt, ap);
+ __vsyslog_internal(pri, fmt, ap, 0);
va_end(ap);
}
ldbl_hidden_def (__syslog, syslog)
ldbl_strong_alias (__syslog, syslog)
+void
+__vsyslog(int pri, const char *fmt, va_list ap)
+{
+ __vsyslog_internal(pri, fmt, ap, 0);
+}
+ldbl_weak_alias (__vsyslog, vsyslog)
+
void
__syslog_chk(int pri, int flag, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
- __vsyslog_chk(pri, flag, fmt, ap);
+ __vsyslog_internal(pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
va_end(ap);
}
void
__vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
+{
+ __vsyslog_internal(pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
+}
+
+void
+__vsyslog_internal(int pri, const char *fmt, va_list ap,
+ unsigned int mode_flags)
{
struct tm now_tm;
time_t now;
@@ -215,11 +229,8 @@ __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
__set_errno (saved_errno);
/* We have the header. Print the user's format into the
- buffer. */
- if (flag == -1)
- vfprintf (f, fmt, ap);
- else
- __vfprintf_chk (f, flag, fmt, ap);
+ buffer. */
+ __vfprintf_internal (f, fmt, ap, mode_flags);
/* Close the memory stream; this will finalize the data
into a malloc'd buffer in BUF. */
@@ -316,15 +327,6 @@ __vsyslog_chk(int pri, int flag, const char *fmt, va_list ap)
if (buf != failbuf)
free (buf);
}
-libc_hidden_def (__vsyslog_chk)
-
-void
-__vsyslog(int pri, const char *fmt, va_list ap)
-{
- __vsyslog_chk (pri, -1, fmt, ap);
-}
-ldbl_hidden_def (__vsyslog, vsyslog)
-ldbl_weak_alias (__vsyslog, vsyslog)
static struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */
diff --git a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
index bda84af0bb..958bbc1834 100644
--- a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
+++ b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
@@ -843,7 +843,7 @@ attribute_compat_text_section
__nldbl___vsyslog_chk (int pri, int flag, const char *fmt, va_list ap)
{
set_no_long_double ();
- __vsyslog_chk (pri, flag, fmt, ap);
+ __vsyslog_internal (pri, fmt, ap, (flag > 0) ? PRINTF_FORTIFY : 0);
clear_no_long_double ();
}
libc_hidden_def (__nldbl___vsyslog_chk)
--
2.14.5