ef10d5274 — BusyBox

Subject

Upgrade mdev to allow commands to be run on create/delete.

SOURCE BUG

This commit was genuinely broken at the time (not related to our build system): scripts/config/mkconfigs.c (2005-08-01 - 2006-10-05 arasi) uretilen bbconfigopts.h icine .config satirlarini kacissiz, ham newline'larla gömüyordu - gecerli C degildi, busybox'un kendi bb_mkdep araci bile parse edemiyordu (7d219aab7 ile duzeltildi, mkconfigs shell scripte cevrildi)

→ Bu hatanin tam hikayesini ve duzeltme diffini gor

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

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Commit Diff GitHub →

include/usage.h +14 -8 util-linux/Config.in +21 -6 util-linux/mdev.c +95 -91

include/usage.h+14 -8

@@ -1799,19 +1799,25 @@ USE_FEATURE_DATE_ISOFMT( \
	"\t-s\tScan /sys and populate /dev during system boot\n\n" \
	"Called with no options (via hotplug) it uses environment variables\n" \
	"to determine which device to add/remove."
-	#ifdef CONFIG_FEATURE_MDEV_CONFIG
-	#define mdev_notes_usage \
+	#define mdev_notes_usage "" \
+	USE_FEATURE_MDEV_CONFIG( \
	"The mdev config file contains lines that look like:\n" \
	" hd[a-z][0-9]* 0:3 660\n\n" \
	"That's device name (with regex match), uid:gid, and permissions.\n\n" \
-	"Optionally, that can be followed (on the same line) by an asterisk\n" \
-	"and a command line to run after creating the corresponding device(s),\n"\
-	"ala:\n\n" \
-	" hdc root:cdrom 660 *ln -s hdc cdrom\n\n" \
+	USE_FEATURE_MDEV_EXEC( \
+	"Optionally, that can be followed (on the same line) by a special character\n" \
+	"and a command line to run after creating/before deleting the corresponding\n" \
+	"device(s). The environment variable $MDEV indicates the active device node\n" \
+	"(which is useful if it's a regex match). For example:\n\n" \
+	" hdc root:cdrom 660 *ln -s $MDEV cdrom\n\n" \
+	"The special characters are @ (run after creating), $ (run before deleting),\n" \
+	"and * (run both after creating and before deleting). The commands run in\n" \
+	"the /dev directory, and use system() which calls /bin/sh.\n\n" \
+	) \
	"Config file parsing stops on the first matching line. If no config\n"\
	"entry is matched, devices are created with default 0:0 660. (Make\n"\
-	"the last line match .* to override this.)\n\n"
-	#endif
+	"the last line match .* to override this.)\n\n" \
+	)

	#define mesg_trivial_usage \
	"[y\|n]"

util-linux/Config.in+21 -6

@@ -265,16 +265,31 @@ config CONFIG_FEATURE_MDEV_CONF

	That's device name (with regex match), uid:gid, and permissions.

-	Optionally, that can be followed (on the same line) by an asterisk
-	and a command line to run after creating the corresponding device(s),
-	ala:
-
-	hdc root:cdrom 660 *ln -s hdc cdrom
-
	Config file parsing stops on the first matching line. If no config
	entry is matched, devices are created with default 0:0 660. (Make
	the last line match .* to override this.)

+	config CONFIG_FEATURE_MDEV_EXEC
+	bool "Support command execution at device addition/removal"
+	default n
+	depends on CONFIG_FEATURE_MDEV_CONF
+	help
+	This adds support for an optional field to /etc/mdev.conf, consisting
+	of a special character and a command line to run after creating the
+	corresponding device(s) and before removing, ala:
+
+	hdc root:cdrom 660 *ln -s $MDEV cdrom
+
+	The $MDEV environment variable is set to the name of the device.
+
+	The special characters and their meanings are:
+	@ Run after creating the device.
+	$ Run before removing the device.
+	* Run both after creating and before removing the device.
+
+	Commands are executed via system() so you need /bin/sh, meaning you
+	probably want to select a default shell in the Shells menu.
+
	config CONFIG_MKSWAP
	bool "mkswap"
	default n

util-linux/mdev.c+95 -91

@@ -8,25 +8,14 @@
	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
	*/

+	#include "busybox.h"
	#include <ctype.h>
-	#include <dirent.h>
	#include <errno.h>
-	#include <fcntl.h>
-	#include <stdio.h>
-	#include <string.h>
	#include <sys/mman.h>
-	#include <sys/stat.h>
	#include <sys/sysmacros.h>
-	#include <sys/types.h>
-	#include <unistd.h>
-	#include <stdlib.h>
-	#include "busybox.h"
	#include "xregex.h"

	#define DEV_PATH "/dev"
-	#define MDEV_CONF "/etc/mdev.conf"
-
-	#include <busybox.h>

	struct mdev_globals
	{
@@ -36,14 +25,15 @@ struct mdev_globals
	#define bbg mdev_globals

	/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
-	static void make_device(char *path)
+	static void make_device(char *path, int delete)
	{
-	char device_name, s;
+	char *device_name;
	int major, minor, type, len, fd;
	int mode = 0660;
	uid_t uid = 0;
	gid_t gid = 0;
	char *temp = path + strlen(path);
+	char *command = NULL;

	/* Try to read major/minor string. Note that the kernel puts \n after
	* the data, so we don't need to worry about null terminating the string
@@ -69,7 +59,7 @@ static void make_device(char *path)
	char conf, pos, *end;

	/* mmap the config file */
-	if (-1 != (fd=open(MDEV_CONF,O_RDONLY))) {
+	if (-1 != (fd=open("/etc/mdev.conf",O_RDONLY))) {
	len = lseek(fd, 0, SEEK_END);
	conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
	if (conf) {
@@ -86,88 +76,89 @@ static void make_device(char *path)
	;

	/* Three fields: regex, uid:gid, mode */
-	for (field=3; field; field--) {
+	for (field=0; field < (3 + ENABLE_FEATURE_MDEV_EXEC);
+	field++)
+	{
	/* Skip whitespace */
-	while (pos<end && isspace(*pos))
-	pos++;
-	if (pos==end \|\| *pos=='#')
-	break;
-	for (end2=pos; end2<end && !isspace(end2) && end2!='#'; end2++)
+	while (pos<end && isspace(*pos)) pos++;
+	if (pos==end \|\| *pos=='#') break;
+	for (end2=pos;
+	end2<end && !isspace(end2) && end2!='#'; end2++)
	;

-	switch (field) {
+	if (!field) {
	/* Regex to match this device */
-	case 3:
-	{
-	char *regex = strndupa(pos,end2-pos);
-	regex_t match;
-	regmatch_t off;
-	int result;
-
-	/* Is this it? */
-	xregcomp(&match,regex,REG_EXTENDED);
-	result = regexec(&match,device_name,1,&off,0);
-	regfree(&match);
-
-	/* If not this device, skip rest of line */
-	if (result \|\| off.rm_so \|\| off.rm_eo!=strlen(device_name))
-	goto end_line;

+	char *regex = strndupa(pos, end2-pos);
+	regex_t match;
+	regmatch_t off;
+	int result;
+
+	/* Is this it? */
+	xregcomp(&match,regex, REG_EXTENDED);
+	result = regexec(&match, device_name, 1, &off, 0);
+	regfree(&match);
+
+	/* If not this device, skip rest of line */
+	if (result \|\| off.rm_so
+	\|\| off.rm_eo != strlen(device_name))
	break;
-	}
+
+	} else if (field == 1) {
	/* uid:gid */
-	case 2:
-	{
-	char *s2;
-
-	/* Find : */
-	for(s=pos; s<end2 && *s!=':'; s++)
-	;
-	if (s == end2)
-	goto end_line;
-
-	/* Parse UID */
-	uid = strtoul(pos,&s2,10);
-	if (s != s2) {
-	struct passwd *pass;
-	pass = getpwnam(strndupa(pos,s-pos));
-	if (!pass)
-	goto end_line;
-	uid = pass->pw_uid;
-	}
-	s++;
-	/* parse GID */
-	gid = strtoul(s,&s2,10);
-	if (end2 != s2) {
-	struct group *grp;
-	grp = getgrnam(strndupa(s,end2-s));
-	if (!grp)
-	goto end_line;
-	gid = grp->gr_gid;
-	}
-	break;
+
+	char s, s2;
+
+	/* Find : */
+	for(s=pos; s<end2 && *s!=':'; s++)
+	;
+	if (s == end2) break;
+
+	/* Parse UID */
+	uid = strtoul(pos,&s2,10);
+	if (s != s2) {
+	struct passwd *pass;
+	pass = getpwnam(strndupa(pos, s-pos));
+	if (!pass) break;
+	uid = pass->pw_uid;
+	}
+	s++;
+	/* parse GID */
+	gid = strtoul(s, &s2, 10);
+	if (end2 != s2) {
+	struct group *grp;
+	grp = getgrnam(strndupa(s, end2-s));
+	if (!grp) break;
+	gid = grp->gr_gid;
	}
+	} else if (field == 2) {
	/* mode */
-	case 1:
-	{
-	mode = strtoul(pos,&pos,8);
-	if (pos != end2)
-	goto end_line;
-	else
-	goto found_device;
+
+	mode = strtoul(pos, &pos, 8);
+	if (pos != end2) break;
+	} else if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
+	// Command to run
+	char s = "@$", *s2;
+	if (!(s2 = strchr(s, *pos++))) {
+	// Force error
+	field = 1;
+	break;
	}
+	if ((s2-s+1) & (1<<delete))
+	command = bb_xstrndup(pos, end-pos);
	}
+
	pos = end2;
	}
-	end_line:
+
	/* Did everything parse happily? */
-	if (field && field!=3)
-	bb_error_msg_and_die("Bad line %d",line);
+
+	if (field > 2) break;
+	if (field) bb_error_msg_and_die("Bad line %d",line);

	/* Next line */
	pos = ++end;
	}
-	found_device:
	munmap(conf, len);
	}
	close(fd);
@@ -175,13 +166,29 @@ found_device:
	}

	umask(0);
-	if (mknod(device_name, mode \| type, makedev(major, minor)) && errno != EEXIST)
-	bb_perror_msg_and_die("mknod %s failed", device_name);
+	if (!delete) {
+	if (mknod(device_name, mode \| type, makedev(major, minor)) && errno != EEXIST)
+	bb_perror_msg_and_die("mknod %s failed", device_name);

-	if (major==bbg.root_major && minor==bbg.root_minor)
-	symlink(device_name, "root");
+	if (major == bbg.root_major && minor == bbg.root_minor)
+	symlink(device_name, "root");

-	if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
+	if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
+	}
+	if (command) {
+	int rc;
+	char *s;
+
+	s=bb_xasprintf("MDEV=%s",device_name);
+	putenv(s);
+	rc = system(command);
+	s[4]=0;
+	putenv(s);
+	free(s);
+	free(command);
+	if (rc == -1) bb_perror_msg_and_die("Couldn't run %s", command);
+	}
+	if (delete) unlink(device_name);
	}

	/* Recursive search of /sys/block or /sys/class. path must be a writeable
@@ -212,7 +219,7 @@ static void find_dev(char *path)

	/* If there's a dev entry, mknod it */

-	if (!strcmp(entry->d_name, "dev")) make_device(path);
+	if (!strcmp(entry->d_name, "dev")) make_device(path, 0);
	}

	closedir(dir);
@@ -247,12 +254,9 @@ int mdev_main(int argc, char *argv[])
	if (!action \|\| !env_path)
	bb_show_usage();

-	if (!strcmp(action, "add")) {
-	sprintf(temp, "/sys%s", env_path);
-	make_device(temp);
-	} else if (!strcmp(action, "remove")) {
-	unlink(strrchr(env_path, '/') + 1);
-	}
+	sprintf(temp, "/sys%s", env_path);
+	if (!strcmp(action, "add")) make_device(temp,0);
+	else if (!strcmp(action, "remove")) make_device(temp,1);
	}

	if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);