Kay Sievers wrote:
> Version 7.
>
> +Also inotify support is required now to run udev.
Hmm. Unsure if this was the intention or not, but this breaks compiling
against "old" glibc versions (the change to unconditionally include
<sys/signalfd.h> doesn't help either).
I have two machines; both run fairly old glibcs, but very recent kernels
(2.6.28.x and 2.6.29.x). I have no <sys/signalfd.h> on one, and neither
that nor <sys/inotify.h> on the other. (I compiled these systems'
glibcs in about 2006 and 2003. Upgrading the kernel is easy; upgrading
glibc to something that will have support for signalfd would entail
recompiling the entire machine, in both cases.)
Below is a patch to emulate <sys/signalfd.h> and <sys/inotify.h> if
those headers don't exist at configure time (via inline functions that
use syscall() directly). It has to pull __NR_xxx (for the various xxx
syscalls) from the kernel includes, which are per-arch, so there are a
few new configure.ac tests to find the appropriate arch. This takes a
while, but isn't run if both <sys/signalfd.h> and <sys/inotify.h> are
present.
Lots of this is copied from glibc-2.10.1, some from the kernel.
----
Don't require glibc to support signalfd and inotify: provide syscall
wrappers if needed.
Signed-Off-By: Bryan Kadzban <bryan@xxxxxxxxxxxxxxxxxxxxx>
configure.ac | 18 ++++++++
udev/Makefile.am | 1 +
udev/udev-sysdeps.h | 107 ++++++++++++++++++++++++++++++++++++++++++++++
udev/udev-watch.c | 2 +-
udev/udevd.c | 3 +-
5 files changed, 128 insertions(+), 3 deletions(-)
diff --git a/configure.ac b/configure.ac
index 9857d52..e2a39cb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,6 +24,24 @@ AC_SUBST(LIBUDEV_LT_AGE)
AC_PATH_PROG([XSLTPROC], [xsltproc])
+AC_CHECK_HEADER([sys/signalfd.h])
+AC_CHECK_HEADER([sys/inotify.h])
+
+if test x"$ac_cv_header_sys_signalfd_h" == xno || \
+ test x"$ac_cv_header_sys_inotify_h" == xno ; then
+ AC_MSG_CHECKING([kernel architecture string])
+ KERN_BASE=/lib/modules/`uname -r`/source
+ KERN_ARCH=`make -C $KERN_BASE -n -p | \
+ sed -n -e '/^hdr-arch/ { s/.*:= // p }'`
+ KERN_UNISTD=$KERN_BASE/arch/$KERN_ARCH/include/asm/unistd.h
+ AC_MSG_RESULT([$KERN_ARCH])
+else
+ KERN_UNISTD=
+fi
+
+AC_DEFINE_UNQUOTED([KERN_UNISTD], ["$KERN_UNISTD"],
+ [Path to kernel unistd.h])
+
AC_ARG_WITH(udev-prefix,
AS_HELP_STRING([--with-udev-prefix=DIR], [add prefix to internal udev
path names]),
[], [with_udev_prefix='${exec_prefix}'])
diff --git a/udev/Makefile.am b/udev/Makefile.am
index 94989e6..6cd2f23 100644
--- a/udev/Makefile.am
+++ b/udev/Makefile.am
@@ -14,6 +14,7 @@ common_ldadd =
common_files = \
udev.h \
+ udev-sysdeps.h \
udev-event.c \
udev-watch.c \
udev-node.c \
diff --git a/udev/udev-sysdeps.h b/udev/udev-sysdeps.h
new file mode 100644
index 0000000..718ee8b
--- /dev/null
+++ b/udev/udev-sysdeps.h
@@ -0,0 +1,107 @@
+/*
+ * wrapping of kernel interfaces
+ *
+ * Copyright (C) 2005-2009 Kay Sievers <kay.sievers@xxxxxxxx>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _UDEV_SYSDEPS_H_
+#define _UDEV_SYSDEPS_H_
+
+#include <stdint.h>
+#include <errno.h>
+
+#if HAVE_SYS_INOTIFY_H
+#include <sys/inotify.h>
+#else
+#include <unistd.h>
+#include KERN_UNISTD
+
+struct inotify_event
+{
+ int wd;
+ uint32_t mask;
+ uint32_t cookie;
+ uint32_t len;
+ char name[1];
+};
+
+#define IN_CREATE 0x00000100
+#define IN_DELETE 0x00000200
+#define IN_MOVED_FROM 0x00000040
+#define IN_MOVED_TO 0x00000080
+#define IN_MOVE (IN_MOVED_FROM | IN_MOVED_TO)
+#define IN_CLOSE_WRITE 0x00000008
+#define IN_IGNORED 0x00008000
+
+static inline int inotify_init(void)
+{
+ return syscall(__NR_inotify_init);
+}
+
+static inline int inotify_add_watch(int fd, const char *name,
+ uint32_t mask)
+{
+ return syscall(__NR_inotify_add_watch, fd, name, mask);
+}
+#endif /* HAVE_SYS_INOTIFY_H */
+
+#if HAVE_SYS_SIGNALFD_H
+#include <sys/signalfd.h>
+#else
+#include <unistd.h>
+#include <signal.h>
+#include KERN_UNISTD
+
+struct signalfd_siginfo {
+ uint32_t ssi_signo; /* Signal number */
+ int32_t ssi_errno; /* Error number (unused) */
+ int32_t ssi_code; /* Signal code */
+ uint32_t ssi_pid; /* PID of sender */
+ uint32_t ssi_uid; /* Real UID of sender */
+ int32_t ssi_fd; /* File descriptor (SIGIO) */
+ uint32_t ssi_tid; /* Kernel timer ID (POSIX timers) */
+ uint32_t ssi_band; /* Band event (SIGIO) */
+ uint32_t ssi_overrun; /* POSIX timer overrun count */
+ uint32_t ssi_trapno; /* Trap number that caused signal */
+ int32_t ssi_status; /* Exit status or signal (SIGCHLD) */
+ int32_t ssi_int; /* Integer sent by sigqueue(2) */
+ uint64_t ssi_ptr; /* Pointer sent by sigqueue(2) */
+ uint64_t ssi_utime; /* User CPU time consumed (SIGCHLD) */
+ uint64_t ssi_stime; /* System CPU time consumed (SIGCHLD) */
+ uint64_t ssi_addr; /* Address that generated signal
+ (for hardware-generated signals) */
+ uint8_t pad[48]; /* Pad size to 128 bytes (allow for
+ additional fields in the future) */
+};
+
+static inline int signalfd(int fd, sigset_t *mask, uint32_t flags)
+{
+ int rv = syscall(__NR_signalfd4, fd, mask, (size_t)8, flags);
+
+ if(rv < 0) {
+ if(flags != 0) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ return syscall(__NR_signalfd, fd, mask, (size_t)8);
+ }
+ else
+ return rv;
+}
+#endif /* HAVE_SYS_SIGNALFD_H */
+
+#endif
diff --git a/udev/udev-watch.c b/udev/udev-watch.c
index 5a49c96..944cd4a 100644
--- a/udev/udev-watch.c
+++ b/udev/udev-watch.c
@@ -26,8 +26,8 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
-#include <sys/inotify.h>
+#include "udev-sysdeps.h"
#include "udev.h"
static int inotify_fd = -1;
diff --git a/udev/udevd.c b/udev/udevd.c
index 2e7a179..a5d05fd 100644
--- a/udev/udevd.c
+++ b/udev/udevd.c
@@ -32,14 +32,13 @@
#include <dirent.h>
#include <sys/prctl.h>
#include <sys/socket.h>
-#include <sys/signalfd.h>
#include <sys/select.h>
#include <sys/poll.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
-#include <sys/inotify.h>
+#include "udev-sysdeps.h"
#include "udev.h"
#define UDEVD_PRIORITY -4
--
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