[PATCH] The Ubuntu Collection: Winter/Spring 2006

[Scott James Remnant <scott@ubuntu.com>]

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Further patches added to udev since the last drop to the list; note that
we've frozen at 079 for the time being as we're planning on releasing
with 2.6.15 so wanted a version "well tested" with that; as such these
patches are aimed at that, though should apply to later.


New patches:

70-ifrename-wait-on-eexist.patch
    This is an improvement to the rename_net_if() function to allow
    interface names to be swapped if probed at the same time.  Should
    the ioctl return the EEXIST error, the interface is instead renamed
    to something temporary (__name) and then goes into a loop
    trying to rename to the desired interface.

    The theory is that another udev process will do the opposite, and
    both renames will succeed.

80-extras-iftab_helper.patch
    Adds an iftab_helper program that parses a tiny subset of the
    ifrename-style /etc/iftab file and outputs the name the interface
    should have.

    As an improvement, if the kernel-assigned name would be taken by an
    interface in this file and the selectors don't match, the interface
    is renamed out of the kernel namespace (_name) so it doesn't clash
    later.

We use the above patches for the following rule:

	SUBSYSTEM=="net", ACTION=="add", \
		PROGRAM="iftab_helper %k $sysfs{address}", \
		NAME="$result"

Scott
-- 
Scott James Remnant
scott@ubuntu.com

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diff -ruNp udev-079~/udev_add.c udev-079/udev_add.c
--- udev-079~/udev_add.c	2005-12-22 23:51:30.000000000 +0000
+++ udev-079/udev_add.c	2006-02-09 22:25:59.498029768 +0000
@@ -32,6 +32,7 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 #include <linux/sockios.h>
+#include <errno.h>
 
 #include "libsysfs/sysfs/libsysfs.h"
 #include "udev_libc_wrapper.h"
@@ -262,10 +263,30 @@ static int rename_net_if(struct udevice 
 	strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
 
 	retval = ioctl(sk, SIOCSIFNAME, &ifr);
-	if (retval != 0)
+	if ((retval != 0) && (errno == EEXIST)) {
+		/* Rename to something temporary then keep trying until
+		 * the name we want stops being hogged. */
+		strlcpy(ifr.ifr_newname, "__", IFNAMSIZ);
+		strlcat(ifr.ifr_newname, udev->name, IFNAMSIZ);
+
+		retval = ioctl(sk, SIOCSIFNAME, &ifr);
+		if (retval != 0)
+			err("error changing net interface name: %s", strerror(errno));
+
+		strlcpy(ifr.ifr_newname, udev->name, IFNAMSIZ);
+		while ((retval = ioctl(sk, SIOCSIFNAME, &ifr)) != 0) {
+			if (errno != EEXIST) {
+				err("error changing net interface name: %s", strerror(errno));
+				break;
+			}
+
+			usleep(10000);
+		}
+	} else if (retval != 0) {
 		err("error changing net interface name: %s", strerror(errno));
-	close(sk);
+	}
 
+	close(sk);
 	return retval;
 }
 

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diff -ruNp udev-079~/extras/iftab/Makefile udev-079/extras/iftab/Makefile
--- udev-079~/extras/iftab/Makefile	1970-01-01 01:00:00.000000000 +0100
+++ udev-079/extras/iftab/Makefile	2006-02-09 21:41:12.115562240 +0000
@@ -0,0 +1,68 @@
+# Copyright © 2006 Canonical Ltd.
+# Author: Scott James Remnant <scott@ubuntu.com>
+#
+# Released under the GNU General Public License, version 2.
+
+PROG = iftab_helper
+OBJ =
+HEADERS =
+GEN_HEADERS =
+MAN_PAGES =
+
+prefix =
+etcdir =	${prefix}/etc
+sbindir =	${prefix}/sbin
+usrbindir =	${prefix}/usr/bin
+usrsbindir =	${prefix}/usr/sbin
+libudevdir =	${prefix}/lib/udev
+mandir =	${prefix}/usr/share/man
+configdir =	${etcdir}/udev/
+
+INSTALL = /usr/bin/install -c
+INSTALL_PROGRAM = ${INSTALL}
+INSTALL_DATA  = ${INSTALL} -m 644
+INSTALL_SCRIPT = ${INSTALL_PROGRAM}
+
+all: $(PROG) $(MAN_PAGES)
+.PHONY: all
+.DEFAULT: all
+
+%.o: %.c $(GEN_HEADERS)
+	$(QUIET) $(CC) -c $(CFLAGS) $< -o $@
+
+$(PROG): %: $(HEADERS) %.o $(OBJS)
+	$(QUIET) $(LD) $(LDFLAGS) $@.o $(OBJS) -o $@ $(LIBUDEV) $(LIBSYSFS) $(LIB_OBJS)
+ifneq ($(strip $(STRIPCMD)),)
+	$(QUIET) $(STRIPCMD) $@
+endif
+
+# man pages
+%.8: %.xml
+	xmlto man $?
+.PRECIOUS: %.8
+
+clean:
+	rm -f $(PROG) $(OBJS) $(GEN_HEADERS)
+.PHONY: clean
+
+install-bin: all
+	$(INSTALL_PROGRAM) -D $(PROG) $(DESTDIR)$(libudevdir)/$(PROG)
+.PHONY: install-bin
+
+uninstall-bin:
+	- rm $(DESTDIR)$(libudevdir)/$(PROG)
+.PHONY: uninstall-bin
+
+install-man:
+	$(INSTALL_DATA) -D $(PROG).8 $(DESTDIR)$(mandir)/man8/$(PROG).8
+	$(INSTALL_DATA) -D iftab.5 $(DESTDIR)$(mandir)/man5/iftab.5
+.PHONY: uninstall-man
+
+uninstall-man:
+	-rm -f $(DESTDIR)$(mandir)/man8/$(PROG).8
+	-rm -f $(DESTDIR)$(mandir)/man5/iftab.5
+.PHONY: uninstall-man
+
+install-config:
+	@echo "no config file to install"
+.PHONY: install-config
diff -ruNp udev-079~/extras/iftab/iftab.5 udev-079/extras/iftab/iftab.5
--- udev-079~/extras/iftab/iftab.5	1970-01-01 01:00:00.000000000 +0100
+++ udev-079/extras/iftab/iftab.5	2006-02-09 21:41:43.575779560 +0000
@@ -0,0 +1,74 @@
+.TH IFTAB 5 "February 2006" "" "Linux Administrator's Manual"
+.SH NAME
+iftab \- assign consistent names to network interfaces
+.SH DESCRIPTION
+The file
+.B /etc/iftab
+contains descriptive information about the various network interfaces and
+is used by
+.BR udev (8)
+and its
+.BR iftab_helper (8)
+to assign consistent names to network interfaces.
+
+.B /etc/iftab
+defines a set of \fImappings\fR.  Each mapping contains an interface name
+and a set of selectors which identify the physical network device that
+should be assigned that name.
+
+If a network device matches all selectors of a mapping, \fBudev\fR will
+rename the interface to the name given by the mapping.
+
+If a network device \fIdoes not\fR match all of the selectors,
+but has the same name as the mapping, \fBudev\fR instead will rename the
+interface so that it does not have the name given by the kernel.
+.\"
+.SH COMPATIBILITY
+Please note that this file format is a subset of that supported by the
+.BR ifrename (8)
+tool you may find in other distributions, and does not (yet) support the
+full range of selectors and features.
+.\"
+.SH MAPPINGS
+Each mapping is described on a separate line, which may be broken across
+multiple lines by terminating the first line with a backslash.  A mapping
+starts with an \fIinterface name\fR and contains a set of \fIselector\fR
+name and value pairs; all separated by space or tabs.
+
+The relationship between selectors of a mapping is a \fIlogical and\fR.
+A mapping only matches a network deivce if all of the selectors for it
+match.
+
+When multiple matching selectors are present, the last in the file is used.
+.\"
+.SH SELECTORS
+Each selector is composed of a selector name and selector value
+separated by spaces or tabs.  Selectors specify a static attribute of a
+network device, the goal being to uniquely identify each piece of hardware.
+
+Currently only the \fBmac\fR selector is supported, other selectors supported
+by the
+.BR ifrename (8)
+tool will be supported as and when required.
+
+.TP
+.BI mac mac-address
+Matches the MAC address of the device which can be obtained by using
+.BR ifconfig (8)
+or
+.BR ip (8).
+.\"
+.SH EXAMPLE
+# This is a comment
+.br
+eth0	mac 00:12:79:59:8D:38
+.br
+eth1	mac 00:0B:CD:5C:9E:2A
+.SH SEE ALSO
+.BR udev (8)
+.BR iftab_helper (8)
+.BR ifconfig (8)
+.BR ip (8)
+.BR ifrename (8)
+.SH AUTHORS
+Scott James Remnant <scott@ubuntu.com>
diff -ruNp udev-079~/extras/iftab/iftab_helper.8 udev-079/extras/iftab/iftab_helper.8
--- udev-079~/extras/iftab/iftab_helper.8	1970-01-01 01:00:00.000000000 +0100
+++ udev-079/extras/iftab/iftab_helper.8	2006-02-09 21:49:48.502059560 +0000
@@ -0,0 +1,33 @@
+.TH IFTAB_HELPER 8 "February 2006" "" "Linux Administrator's Manual"
+.SH NAME
+iftab_helper \- udev callout to parse /etc/iftab and name network devices
+.SH SYNOPSIS
+.BI iftab_helper
+\fIdevicename\fP \fIaddress\fP
+.SH DESCRIPTION
+.B iftab_helper
+is normally called from a udev rule to provide the name for a detected
+network device.  Udev can use this information to rename devices and thus
+provide consistent names for network devices.
+.SH USAGE
+.B iftab_helper
+looks up the address specified on the command-line in the \fI/etc/iftab\fR
+file and returns the name assigned to it in that file.  If it is not present
+it checks whether the kernel-assigned name is assigned to a different device
+in that file and if so returns a new name for the device.
+
+.B iftab_helper
+is not responsible for performing the actual renaming, that is instead
+eperformed by udev using a NAME rule.  This replaces the functionality
+previously offered by
+.BR ifrename (8)
+though note that
+.B iftab_helper
+does not support as wide a range of selectors for devices and files may
+need to be simplified.
+.SH SEE ALSO
+.BR iftab (5)
+.BR ifrename (8)
+.BR udev (8)
+.SH AUTHORS
+Scott James Remnant <scott@ubuntu.com>
diff -ruNp udev-079~/extras/iftab/iftab_helper.c udev-079/extras/iftab/iftab_helper.c
--- udev-079~/extras/iftab/iftab_helper.c	1970-01-01 01:00:00.000000000 +0100
+++ udev-079/extras/iftab/iftab_helper.c	2006-02-09 21:49:09.995913384 +0000
@@ -0,0 +1,205 @@
+/*
+ * iftab_helper - parses /etc/iftab and outputs network device name
+ *
+ * Copyright © 2006 Canonical Ltd.
+ * Author: Scott James Remnant <scott@ubuntu.com>
+ *
+ *	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 version 2 of the License.
+ *
+ *	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, write to the Free Software Foundation, Inc.,
+ *	51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "../../logging.h"
+#include "../../udev_utils.h"
+
+#define IFTAB "/etc/iftab"
+
+#ifdef USE_LOG
+void log_message(int priority, const char *format, ...)
+{
+	va_list args;
+	static int udev_log = -1;
+
+	if (udev_log == -1) {
+		const char *value;
+
+		value = getenv("UDEV_LOG");
+		if (value)
+			udev_log = log_priority(value);
+		else
+			udev_log = LOG_ERR;
+	}
+
+	if (priority > udev_log)
+		return;
+
+	va_start(args, format);
+	vprintf(format, args);
+	if (format[strlen(format)-1] != '\n')
+		printf("\n");
+	vsyslog(priority, format, args);
+	va_end(args);
+}
+#endif
+
+char *next_token(char **linepos)
+{
+	char *token = *linepos;
+
+	/* read up to whitespace */
+	while (**linepos && !isspace(**linepos))
+		(*linepos)++;
+
+	/* split the string and skip over whitespace */
+	if (**linepos) {
+		*((*linepos)++) = '\0';
+		while (isspace(**linepos))
+			(*linepos)++;
+	}
+
+	return token;
+}
+
+const char *whats_my_name(const char *name, const char *address)
+{
+	static char iftab_name[NAME_SIZE] = "";
+	char *buf;
+	size_t bufsize, cur, lineno;
+
+	if (file_map(IFTAB, &buf, &bufsize)) {
+		if (errno != ENOENT)
+			err("%s: unable to open: %s", IFTAB, strerror(errno));
+		return NULL;
+	}
+
+	cur = 0;
+	lineno = 0;
+	while (cur < bufsize) {
+		char line[LINE_SIZE], *bufline, *linepos;
+		char *ifname;
+		size_t count;
+		int match = 1;
+
+		count = buf_get_line(buf, bufsize, cur);
+		bufline = &buf[cur];
+		cur += count+1;
+		lineno++;
+
+		if (count >= sizeof(line)) {
+			err("%s:%d: line too long", IFTAB, lineno);
+			continue;
+		}
+
+		/* eat initial whitespace */
+		while ((count > 0) && isspace(bufline[0])) {
+			bufline++;
+			count--;
+		}
+		if (!count)
+			continue;
+
+		/* comment? */
+		if (bufline[0] == '#')
+			continue;
+
+		/* copy into buffer */
+		memcpy(line, bufline, count);
+		line[count] = '\0';
+		linepos = line;
+
+		/* up to the first whitespace is the interface name */
+		ifname = next_token(&linepos);
+		if (!*linepos) {
+			err("%s:%d: no selectors for %s", IFTAB, lineno, ifname);
+			continue;
+		}
+
+		while (*linepos) {
+			char *selector, *value;
+
+			/* read selector name and value */
+			selector = next_token(&linepos);
+			if (!*linepos) {
+				err("%s:%d: no value after %s selector for %s", IFTAB, lineno, selector, ifname);
+				break;
+			}
+			value = next_token(&linepos);
+
+			if (!strcasecmp(selector, "mac")) {
+				if (strcasecmp(value, address))
+					match = 0;
+
+			} else {
+				err("%s:%d: unknown or unsupported %s selector for %s", IFTAB, lineno, selector, ifname);
+			}
+		}
+
+		if (match) {
+			/* Matched details: use assigned name */
+			strncpy(iftab_name, ifname, sizeof(iftab_name));
+			iftab_name[sizeof(iftab_name)-1] = '\0';
+		} else if (!strcasecmp(ifname, name)) {
+			/* Name already used: invent new name */
+			snprintf(iftab_name, sizeof(iftab_name), "_%s", name);
+		}
+	}
+
+	file_unmap(buf, bufsize);
+	return iftab_name;
+}
+
+
+int main(int argc, char *argv[])
+{
+	const char *name = NULL, *address = NULL, *iftab_name;
+	int ret = 0;
+	int i;
+
+	logging_init("iftab_helper");
+
+	for (i = 1; i < argc; i++) {
+		if (!name) {
+			name = argv[i];
+		} else if (!address) {
+			address = argv[i];
+		}
+	}
+
+	if (!name) {
+		err("no device name specified");
+		ret = 1;
+		goto exit;
+	}
+
+	if (!address) {
+		err("no mac address specified");
+		ret = 1;
+		goto exit;
+	}
+
+	iftab_name = whats_my_name(name, address);
+	if (!*iftab_name)
+		iftab_name = name;
+
+	printf("%s\n", iftab_name);
+
+exit:
+	logging_close();
+	return ret;
+}

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