emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
75d151e31d
busybox/util-linux/mdev.c
Denys Vlasenko 4eed2c6c50 Update menuconfig items with approximate applet sizes 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-07-18 22:01:24 +02:00

1152 lines
31 KiB
C
Raw Blame History

/* vi: set sw=4 ts=4: */
/*
* mdev - Mini udev for busybox
*
* Copyright 2005 Rob Landley <rob@landley.net>
* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config MDEV
//config: bool "mdev (16 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: mdev is a mini-udev implementation for dynamically creating device
//config: nodes in the /dev directory.
//config:
//config: For more information, please see docs/mdev.txt
//config:
//config:config FEATURE_MDEV_CONF
//config: bool "Support /etc/mdev.conf"
//config: default y
//config: depends on MDEV
//config: help
//config: Add support for the mdev config file to control ownership and
//config: permissions of the device nodes.
//config:
//config: For more information, please see docs/mdev.txt
//config:
//config:config FEATURE_MDEV_RENAME
//config: bool "Support subdirs/symlinks"
//config: default y
//config: depends on FEATURE_MDEV_CONF
//config: help
//config: Add support for renaming devices and creating symlinks.
//config:
//config: For more information, please see docs/mdev.txt
//config:
//config:config FEATURE_MDEV_RENAME_REGEXP
//config: bool "Support regular expressions substitutions when renaming device"
//config: default y
//config: depends on FEATURE_MDEV_RENAME
//config: help
//config: Add support for regular expressions substitutions when renaming
//config: device.
//config:
//config:config FEATURE_MDEV_EXEC
//config: bool "Support command execution at device addition/removal"
//config: default y
//config: depends on FEATURE_MDEV_CONF
//config: help
//config: This adds support for an optional field to /etc/mdev.conf for
//config: executing commands when devices are created/removed.
//config:
//config: For more information, please see docs/mdev.txt
//config:
//config:config FEATURE_MDEV_LOAD_FIRMWARE
//config: bool "Support loading of firmwares"
//config: default y
//config: depends on MDEV
//config: help
//config: Some devices need to load firmware before they can be usable.
//config:
//config: These devices will request userspace look up the files in
//config: /lib/firmware/ and if it exists, send it to the kernel for
//config: loading into the hardware.
//applet:IF_MDEV(APPLET(mdev, BB_DIR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_MDEV) += mdev.o
//usage:#define mdev_trivial_usage
//usage: "[-s]"
//usage:#define mdev_full_usage "\n\n"
//usage: "mdev -s is to be run during boot to scan /sys and populate /dev.\n"
//usage: "\n"
//usage: "Bare mdev is a kernel hotplug helper. To activate it:\n"
//usage: " echo /sbin/mdev >/proc/sys/kernel/hotplug\n"
//usage: IF_FEATURE_MDEV_CONF(
//usage: "\n"
//usage: "It uses /etc/mdev.conf with lines\n"
//usage: " [-][ENV=regex;]...DEVNAME UID:GID PERM"
//usage: IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]")
//usage: IF_FEATURE_MDEV_EXEC(" [@|$|*PROG]")
//usage: "\n"
//usage: "where DEVNAME is device name regex, @major,minor[-minor2], or\n"
//usage: "environment variable regex. A common use of the latter is\n"
//usage: "to load modules for hotplugged devices:\n"
//usage: " $MODALIAS=.* 0:0 660 @modprobe \"$MODALIAS\"\n"
//usage: )
//usage: "\n"
//usage: "If /dev/mdev.seq file exists, mdev will wait for its value\n"
//usage: "to match $SEQNUM variable. This prevents plug/unplug races.\n"
//usage: "To activate this feature, create empty /dev/mdev.seq at boot.\n"
//usage: "\n"
//usage: "If /dev/mdev.log file exists, debug log will be appended to it."
#include "libbb.h"
#include "common_bufsiz.h"
#include "xregex.h"
/* "mdev -s" scans /sys/class/xxx, looking for directories which have dev
* file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev
* contains "4:0\n". Directory name is taken as device name, path component
* directly after /sys/class/ as subsystem. In this example, "tty0" and "tty".
* Then mdev creates the /dev/device_name node.
* If /sys/class/.../dev file does not exist, mdev still may act
* on this device: see "@|$|*command args..." parameter in config file.
*
* mdev w/o parameters is called as hotplug helper. It takes device
* and subsystem names from $DEVPATH and $SUBSYSTEM, extracts
* maj,min from "/sys/$DEVPATH/dev" and also examines
* $ACTION ("add"/"delete") and $FIRMWARE.
*
* If action is "add", mdev creates /dev/device_name similarly to mdev -s.
* (todo: explain "delete" and $FIRMWARE)
*
* If /etc/mdev.conf exists, it may modify /dev/device_name's properties.
*
* Leading minus in 1st field means "don't stop on this line", otherwise
* search is stopped after the matching line is encountered.
*
* $envvar=regex format is useful for loading modules for hot-plugged devices
* which do not have driver loaded yet. In this case /sys/class/.../dev
* does not exist, but $MODALIAS is set to needed module's name
* (actually, an alias to it) by kernel. This rule instructs mdev
* to load the module and exit:
* $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"
* The kernel will generate another hotplug event when /sys/class/.../dev
* file appears.
*
* When line matches, the device node is created, chmod'ed and chown'ed,
* moved to path, and if >path, a symlink to moved node is created,
* all this if /sys/class/.../dev exists.
* Examples:
* =loop/ - moves to /dev/loop
* >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink
*
* Then "command args..." is executed (via sh -c 'command args...').
* @:execute on creation, $:on deletion, *:on both.
* This happens regardless of /sys/class/.../dev existence.
*/
/* Kernel's hotplug environment constantly changes.
* Here are new cases I observed on 3.1.0:
*
* Case with $DEVNAME and $DEVICE, not just $DEVPATH:
* ACTION=add
* BUSNUM=001
* DEVICE=/proc/bus/usb/001/003
* DEVNAME=bus/usb/001/003
* DEVNUM=003
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5
* DEVTYPE=usb_device
* MAJOR=189
* MINOR=2
* PRODUCT=18d1/4e12/227
* SUBSYSTEM=usb
* TYPE=0/0/0
*
* Case with $DEVICE, but no $DEVNAME - apparenty, usb iface notification?
* "Please load me a module" thing?
* ACTION=add
* DEVICE=/proc/bus/usb/001/003
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0
* DEVTYPE=usb_interface
* INTERFACE=8/6/80
* MODALIAS=usb:v18D1p4E12d0227dc00dsc00dp00ic08isc06ip50
* PRODUCT=18d1/4e12/227
* SUBSYSTEM=usb
* TYPE=0/0/0
*
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5
* DEVTYPE=scsi_host
* SUBSYSTEM=scsi
*
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/scsi_host/host5
* SUBSYSTEM=scsi_host
*
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0
* DEVTYPE=scsi_target
* SUBSYSTEM=scsi
*
* Case with strange $MODALIAS:
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0
* DEVTYPE=scsi_device
* MODALIAS=scsi:t-0x00
* SUBSYSTEM=scsi
*
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/scsi_disk/5:0:0:0
* SUBSYSTEM=scsi_disk
*
* ACTION=add
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/scsi_device/5:0:0:0
* SUBSYSTEM=scsi_device
*
* Case with explicit $MAJOR/$MINOR (no need to read /sys/$DEVPATH/dev?):
* ACTION=add
* DEVNAME=bsg/5:0:0:0
* DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/bsg/5:0:0:0
* MAJOR=253
* MINOR=1
* SUBSYSTEM=bsg
*
* ACTION=add
* DEVPATH=/devices/virtual/bdi/8:16
* SUBSYSTEM=bdi
*
* ACTION=add
* DEVNAME=sdb
* DEVPATH=/block/sdb
* DEVTYPE=disk
* MAJOR=8
* MINOR=16
* SUBSYSTEM=block
*
* Case with ACTION=change:
* ACTION=change
* DEVNAME=sdb
* DEVPATH=/block/sdb
* DEVTYPE=disk
* DISK_MEDIA_CHANGE=1
* MAJOR=8
* MINOR=16
* SUBSYSTEM=block
*/
#define DEBUG_LVL 2
#if DEBUG_LVL >= 1
# define dbg1(...) do { if (G.verbose) bb_error_msg(__VA_ARGS__); } while(0)
#else
# define dbg1(...) ((void)0)
#endif
#if DEBUG_LVL >= 2
# define dbg2(...) do { if (G.verbose >= 2) bb_error_msg(__VA_ARGS__); } while(0)
#else
# define dbg2(...) ((void)0)
#endif
#if DEBUG_LVL >= 3
# define dbg3(...) do { if (G.verbose >= 3) bb_error_msg(__VA_ARGS__); } while(0)
#else
# define dbg3(...) ((void)0)
#endif
static const char keywords[] ALIGN1 = "add\0remove\0"; // "change\0"
enum { OP_add, OP_remove };
struct envmatch {
struct envmatch *next;
char *envname;
regex_t match;
};
struct rule {
bool keep_matching;
bool regex_compiled;
mode_t mode;
int maj, min0, min1;
struct bb_uidgid_t ugid;
char *envvar;
char *ren_mov;
IF_FEATURE_MDEV_EXEC(char *r_cmd;)
regex_t match;
struct envmatch *envmatch;
};
struct globals {
int root_major, root_minor;
smallint verbose;
char *subsystem;
char *subsys_env; /* for putenv("SUBSYSTEM=subsystem") */
#if ENABLE_FEATURE_MDEV_CONF
const char *filename;
parser_t *parser;
struct rule **rule_vec;
unsigned rule_idx;
#endif
struct rule cur_rule;
char timestr[sizeof("HH:MM:SS.123456")];
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { \
setup_common_bufsiz(); \
IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.maj = -1;) \
IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.mode = 0660;) \
} while (0)
/* Prevent infinite loops in /sys symlinks */
#define MAX_SYSFS_DEPTH 3
/* We use additional bytes in make_device() */
#define SCRATCH_SIZE 128
#if ENABLE_FEATURE_MDEV_CONF
static void make_default_cur_rule(void)
{
memset(&G.cur_rule, 0, sizeof(G.cur_rule));
G.cur_rule.maj = -1; /* "not a @major,minor rule" */
G.cur_rule.mode = 0660;
}
static void clean_up_cur_rule(void)
{
struct envmatch *e;
free(G.cur_rule.envvar);
free(G.cur_rule.ren_mov);
if (G.cur_rule.regex_compiled)
regfree(&G.cur_rule.match);
IF_FEATURE_MDEV_EXEC(free(G.cur_rule.r_cmd);)
e = G.cur_rule.envmatch;
while (e) {
free(e->envname);
regfree(&e->match);
e = e->next;
}
make_default_cur_rule();
}
static char *parse_envmatch_pfx(char *val)
{
struct envmatch **nextp = &G.cur_rule.envmatch;
for (;;) {
struct envmatch *e;
char *semicolon;
char *eq = strchr(val, '=');
if (!eq /* || eq == val? */)
return val;
if (endofname(val) != eq)
return val;
semicolon = strchr(eq, ';');
if (!semicolon)
return val;
/* ENVVAR=regex;... */
*nextp = e = xzalloc(sizeof(*e));
nextp = &e->next;
e->envname = xstrndup(val, eq - val);
*semicolon = '\0';
xregcomp(&e->match, eq + 1, REG_EXTENDED);
*semicolon = ';';
val = semicolon + 1;
}
}
static void parse_next_rule(void)
{
/* Note: on entry, G.cur_rule is set to default */
while (1) {
char *tokens[4];
char *val;
/* No PARSE_EOL_COMMENTS, because command may contain '#' chars */
if (!config_read(G.parser, tokens, 4, 3, "# \t", PARSE_NORMAL & ~PARSE_EOL_COMMENTS))
break;
/* Fields: [-]regex uid:gid mode [alias] [cmd] */
dbg3("token1:'%s'", tokens[1]);
/* 1st field */
val = tokens[0];
G.cur_rule.keep_matching = ('-' == val[0]);
val += G.cur_rule.keep_matching; /* swallow leading dash */
val = parse_envmatch_pfx(val);
if (val[0] == '@') {
/* @major,minor[-minor2] */
/* (useful when name is ambiguous:
* "/sys/class/usb/lp0" and
* "/sys/class/printer/lp0")
*/
int sc = sscanf(val, "@%u,%u-%u", &G.cur_rule.maj, &G.cur_rule.min0, &G.cur_rule.min1);
if (sc < 2 || G.cur_rule.maj < 0) {
bb_error_msg("bad @maj,min on line %d", G.parser->lineno);
goto next_rule;
}
if (sc == 2)
G.cur_rule.min1 = G.cur_rule.min0;
} else {
char *eq = strchr(val, '=');
if (val[0] == '$') {
/* $ENVVAR=regex ... */
val++;
if (!eq) {
bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno);
goto next_rule;
}
G.cur_rule.envvar = xstrndup(val, eq - val);
val = eq + 1;
}
xregcomp(&G.cur_rule.match, val, REG_EXTENDED);
G.cur_rule.regex_compiled = 1;
}
/* 2nd field: uid:gid - device ownership */
if (get_uidgid(&G.cur_rule.ugid, tokens[1]) == 0) {
bb_error_msg("unknown user/group '%s' on line %d", tokens[1], G.parser->lineno);
goto next_rule;
}
/* 3rd field: mode - device permissions */
G.cur_rule.mode = bb_parse_mode(tokens[2], G.cur_rule.mode);
/* 4th field (opt): ">|=alias" or "!" to not create the node */
val = tokens[3];
if (ENABLE_FEATURE_MDEV_RENAME && val && strchr(">=!", val[0])) {
char *s = skip_non_whitespace(val);
G.cur_rule.ren_mov = xstrndup(val, s - val);
val = skip_whitespace(s);
}
if (ENABLE_FEATURE_MDEV_EXEC && val && val[0]) {
const char *s = "$@*";
const char *s2 = strchr(s, val[0]);
if (!s2) {
bb_error_msg("bad line %u", G.parser->lineno);
goto next_rule;
}
IF_FEATURE_MDEV_EXEC(G.cur_rule.r_cmd = xstrdup(val);)
}
return;
next_rule:
clean_up_cur_rule();
} /* while (config_read) */
dbg3("config_close(G.parser)");
config_close(G.parser);
G.parser = NULL;
return;
}
/* If mdev -s, we remember rules in G.rule_vec[].
* Otherwise, there is no point in doing it, and we just
* save only one parsed rule in G.cur_rule.
*/
static const struct rule *next_rule(void)
{
struct rule *rule;
/* Open conf file if we didn't do it yet */
if (!G.parser && G.filename) {
dbg3("config_open('%s')", G.filename);
G.parser = config_open2(G.filename, fopen_for_read);
G.filename = NULL;
}
if (G.rule_vec) {
/* mdev -s */
/* Do we have rule parsed already? */
if (G.rule_vec[G.rule_idx]) {
dbg3("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
return G.rule_vec[G.rule_idx++];
}
make_default_cur_rule();
} else {
/* not mdev -s */
clean_up_cur_rule();
}
/* Parse one more rule if file isn't fully read */
rule = &G.cur_rule;
if (G.parser) {
parse_next_rule();
if (G.rule_vec) { /* mdev -s */
rule = xmemdup(&G.cur_rule, sizeof(G.cur_rule));
G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
G.rule_vec[G.rule_idx++] = rule;
dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
}
}
return rule;
}
static int env_matches(struct envmatch *e)
{
while (e) {
int r;
char *val = getenv(e->envname);
if (!val)
return 0;
r = regexec(&e->match, val, /*size*/ 0, /*range[]*/ NULL, /*eflags*/ 0);
if (r != 0) /* no match */
return 0;
e = e->next;
}
return 1;
}
#else
# define next_rule() (&G.cur_rule)
#endif
static void mkdir_recursive(char *name)
{
/* if name has many levels ("dir1/dir2"),
* bb_make_directory() will create dir1 according to umask,
* not according to its "mode" parameter.
* Since we run with umask=0, need to temporarily switch it.
*/
umask(022); /* "dir1" (if any) will be 0755 too */
bb_make_directory(name, 0755, FILEUTILS_RECUR);
umask(0);
}
/* Builds an alias path.
* This function potentionally reallocates the alias parameter.
* Only used for ENABLE_FEATURE_MDEV_RENAME
*/
static char *build_alias(char *alias, const char *device_name)
{
char *dest;
/* ">bar/": rename to bar/device_name */
/* ">bar[/]baz": rename to bar[/]baz */
dest = strrchr(alias, '/');
if (dest) { /* ">bar/[baz]" ? */
*dest = '\0'; /* mkdir bar */
mkdir_recursive(alias);
*dest = '/';
if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
dest = alias;
alias = concat_path_file(alias, device_name);
free(dest);
}
}
return alias;
}
/* mknod in /dev based on a path like "/sys/block/hda/hda1"
* NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
* after NUL, but we promise to not mangle it (IOW: to restore NUL if needed).
* NB2: "mdev -s" may call us many times, do not leak memory/fds!
*
* device_name = $DEVNAME (may be NULL)
* path = /sys/$DEVPATH
*/
static void make_device(char *device_name, char *path, int operation)
{
int major, minor, type, len;
char *path_end = path + strlen(path);
/* 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
* because sscanf() will stop at the first nondigit, which \n is.
* We also depend on path having writeable space after it.
*/
major = -1;
if (operation == OP_add) {
strcpy(path_end, "/dev");
len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
*path_end = '\0';
if (len < 1) {
if (!ENABLE_FEATURE_MDEV_EXEC)
return;
/* no "dev" file, but we can still run scripts
* based on device name */
} else if (sscanf(path_end + 1, "%u:%u", &major, &minor) == 2) {
dbg1("dev %u,%u", major, minor);
} else {
major = -1;
}
}
/* else: for delete, -1 still deletes the node, but < -1 suppresses that */
/* Determine device name */
if (!device_name) {
/*
* There was no $DEVNAME envvar (for example, mdev -s never has).
* But it is very useful: it contains the *path*, not only basename,
* Thankfully, uevent file has it.
* Example of .../sound/card0/controlC0/uevent file on Linux-3.7.7:
* MAJOR=116
* MINOR=7
* DEVNAME=snd/controlC0
*/
strcpy(path_end, "/uevent");
len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
if (len < 0)
len = 0;
*path_end = '\0';
path_end[1 + len] = '\0';
device_name = strstr(path_end + 1, "\nDEVNAME=");
if (device_name) {
device_name += sizeof("\nDEVNAME=")-1;
strchrnul(device_name, '\n')[0] = '\0';
} else {
/* Fall back to just basename */
device_name = (char*) bb_basename(path);
}
}
/* Determine device type */
/*
* http://kernel.org/doc/pending/hotplug.txt says that only
* "/sys/block/..." is for block devices. "/sys/bus" etc is not.
* But since 2.6.25 block devices are also in /sys/class/block.
* We use strstr("/block/") to forestall future surprises.
*/
type = S_IFCHR;
if (strstr(path, "/block/") || (G.subsystem && is_prefixed_with(G.subsystem, "block")))
type = S_IFBLK;
#if ENABLE_FEATURE_MDEV_CONF
G.rule_idx = 0; /* restart from the beginning (think mdev -s) */
#endif
for (;;) {
const char *str_to_match;
regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
char *command;
char *alias;
char aliaslink = aliaslink; /* for compiler */
char *node_name;
const struct rule *rule;
str_to_match = device_name;
rule = next_rule();
#if ENABLE_FEATURE_MDEV_CONF
if (!env_matches(rule->envmatch))
continue;
if (rule->maj >= 0) { /* @maj,min rule */
if (major != rule->maj)
continue;
if (minor < rule->min0 || minor > rule->min1)
continue;
memset(off, 0, sizeof(off));
goto rule_matches;
}
if (rule->envvar) { /* $envvar=regex rule */
str_to_match = getenv(rule->envvar);
dbg3("getenv('%s'):'%s'", rule->envvar, str_to_match);
if (!str_to_match)
continue;
}
/* else: str_to_match = device_name */
if (rule->regex_compiled) {
int regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0);
dbg3("regex_match for '%s':%d", str_to_match, regex_match);
//bb_error_msg("matches:");
//for (int i = 0; i < ARRAY_SIZE(off); i++) {
// if (off[i].rm_so < 0) continue;
// bb_error_msg("match %d: '%.*s'\n", i,
// (int)(off[i].rm_eo - off[i].rm_so),
// device_name + off[i].rm_so);
//}
if (regex_match != 0
/* regexec returns whole pattern as "range" 0 */
|| off[0].rm_so != 0
|| (int)off[0].rm_eo != (int)strlen(str_to_match)
) {
continue; /* this rule doesn't match */
}
}
/* else: it's final implicit "match-all" rule */
rule_matches:
dbg2("rule matched, line %d", G.parser ? G.parser->lineno : -1);
#endif
/* Build alias name */
alias = NULL;
if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) {
aliaslink = rule->ren_mov[0];
if (aliaslink == '!') {
/* "!": suppress node creation/deletion */
major = -2;
}
else if (aliaslink == '>' || aliaslink == '=') {
if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
char *s;
char *p;
unsigned n;
/* substitute %1..9 with off[1..9], if any */
n = 0;
s = rule->ren_mov;
while (*s)
if (*s++ == '%')
n++;
p = alias = xzalloc(strlen(rule->ren_mov) + n * strlen(str_to_match));
s = rule->ren_mov + 1;
while (*s) {
*p = *s;
if ('%' == *s) {
unsigned i = (s[1] - '0');
if (i <= 9 && off[i].rm_so >= 0) {
n = off[i].rm_eo - off[i].rm_so;
strncpy(p, str_to_match + off[i].rm_so, n);
p += n - 1;
s++;
}
}
p++;
s++;
}
} else {
alias = xstrdup(rule->ren_mov + 1);
}
}
}
dbg3("alias:'%s'", alias);
command = NULL;
IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
if (command) {
/* Are we running this command now?
* Run @cmd on create, $cmd on delete, *cmd on any
*/
if ((command[0] == '@' && operation == OP_add)
|| (command[0] == '$' && operation == OP_remove)
|| (command[0] == '*')
) {
command++;
} else {
command = NULL;
}
}
dbg3("command:'%s'", command);
/* "Execute" the line we found */
node_name = device_name;
if (ENABLE_FEATURE_MDEV_RENAME && alias) {
node_name = alias = build_alias(alias, device_name);
dbg3("alias2:'%s'", alias);
}
if (operation == OP_add && major >= 0) {
char *slash = strrchr(node_name, '/');
if (slash) {
*slash = '\0';
mkdir_recursive(node_name);
*slash = '/';
}
if (ENABLE_FEATURE_MDEV_CONF) {
dbg1("mknod %s (%d,%d) %o"
" %u:%u",
node_name, major, minor, rule->mode | type,
rule->ugid.uid, rule->ugid.gid
);
} else {
dbg1("mknod %s (%d,%d) %o",
node_name, major, minor, rule->mode | type
);
}
if (mknod(node_name, rule->mode | type, makedev(major, minor)) && errno != EEXIST)
bb_perror_msg("can't create '%s'", node_name);
if (ENABLE_FEATURE_MDEV_CONF) {
chmod(node_name, rule->mode);
chown(node_name, rule->ugid.uid, rule->ugid.gid);
}
if (major == G.root_major && minor == G.root_minor)
symlink(node_name, "root");
if (ENABLE_FEATURE_MDEV_RENAME && alias) {
if (aliaslink == '>') {
//TODO: on devtmpfs, device_name already exists and symlink() fails.
//End result is that instead of symlink, we have two nodes.
//What should be done?
dbg1("symlink: %s", device_name);
symlink(node_name, device_name);
}
}
}
if (ENABLE_FEATURE_MDEV_EXEC && command) {
/* setenv will leak memory, use putenv/unsetenv/free */
char *s = xasprintf("%s=%s", "MDEV", node_name);
putenv(s);
dbg1("running: %s", command);
if (system(command) == -1)
bb_perror_msg("can't run '%s'", command);
bb_unsetenv_and_free(s);
}
if (operation == OP_remove && major >= -1) {
if (ENABLE_FEATURE_MDEV_RENAME && alias) {
if (aliaslink == '>') {
dbg1("unlink: %s", device_name);
unlink(device_name);
}
}
dbg1("unlink: %s", node_name);
unlink(node_name);
}
if (ENABLE_FEATURE_MDEV_RENAME)
free(alias);
/* We found matching line.
* Stop unless it was prefixed with '-'
*/
if (!ENABLE_FEATURE_MDEV_CONF || !rule->keep_matching)
break;
} /* for (;;) */
}
/* File callback for /sys/ traversal.
* We act only on "/sys/.../dev" (pseudo)file
*/
static int FAST_FUNC fileAction(const char *fileName,
struct stat *statbuf UNUSED_PARAM,
void *userData,
int depth UNUSED_PARAM)
{
size_t len = strlen(fileName) - 4; /* can't underflow */
char *path = userData; /* char array[PATH_MAX + SCRATCH_SIZE] */
char subsys[PATH_MAX];
int res;
/* Is it a ".../dev" file? (len check is for paranoid reasons) */
if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX - 32)
return FALSE; /* not .../dev */
strcpy(path, fileName);
path[len] = '\0';
/* Read ".../subsystem" symlink in the same directory where ".../dev" is */
strcpy(subsys, path);
strcpy(subsys + len, "/subsystem");
res = readlink(subsys, subsys, sizeof(subsys)-1);
if (res > 0) {
subsys[res] = '\0';
free(G.subsystem);
if (G.subsys_env) {
bb_unsetenv_and_free(G.subsys_env);
G.subsys_env = NULL;
}
/* Set G.subsystem and $SUBSYSTEM from symlink's last component */
G.subsystem = strrchr(subsys, '/');
if (G.subsystem) {
G.subsystem = xstrdup(G.subsystem + 1);
G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
putenv(G.subsys_env);
}
}
make_device(/*DEVNAME:*/ NULL, path, OP_add);
return TRUE;
}
/* Directory callback for /sys/ traversal */
static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
struct stat *statbuf UNUSED_PARAM,
void *userData UNUSED_PARAM,
int depth)
{
return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
}
/* For the full gory details, see linux/Documentation/firmware_class/README
*
* Firmware loading works like this:
* - kernel sets FIRMWARE env var
* - userspace checks /lib/firmware/$FIRMWARE
* - userspace waits for /sys/$DEVPATH/loading to appear
* - userspace writes "1" to /sys/$DEVPATH/loading
* - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
* - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
* - kernel loads firmware into device
*/
static void load_firmware(const char *firmware, const char *sysfs_path)
{
int cnt;
int firmware_fd, loading_fd;
/* check for /lib/firmware/$FIRMWARE */
firmware_fd = -1;
if (chdir("/lib/firmware") == 0)
firmware_fd = open(firmware, O_RDONLY); /* can fail */
/* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
xchdir(sysfs_path);
for (cnt = 0; cnt < 30; ++cnt) {
loading_fd = open("loading", O_WRONLY);
if (loading_fd >= 0)
goto loading;
sleep(1);
}
goto out;
loading:
cnt = 0;
if (firmware_fd >= 0) {
int data_fd;
/* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
if (full_write(loading_fd, "1", 1) != 1)
goto out;
/* load firmware into /sys/$DEVPATH/data */
data_fd = open("data", O_WRONLY);
if (data_fd < 0)
goto out;
cnt = bb_copyfd_eof(firmware_fd, data_fd);
if (ENABLE_FEATURE_CLEAN_UP)
close(data_fd);
}
/* Tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading"
* Note: we emit -1 also if firmware file wasn't found.
* There are cases when otherwise kernel would wait for minutes
* before timing out.
*/
if (cnt > 0)
full_write(loading_fd, "0", 1);
else
full_write(loading_fd, "-1", 2);
out:
xchdir("/dev");
if (ENABLE_FEATURE_CLEAN_UP) {
close(firmware_fd);
close(loading_fd);
}
}
static char *curtime(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
sprintf(
strftime_HHMMSS(G.timestr, sizeof(G.timestr), &tv.tv_sec),
".%06u",
(unsigned)tv.tv_usec
);
return G.timestr;
}
static void open_mdev_log(const char *seq, unsigned my_pid)
{
int logfd = open("mdev.log", O_WRONLY | O_APPEND);
if (logfd >= 0) {
xmove_fd(logfd, STDERR_FILENO);
G.verbose = 2;
applet_name = xasprintf("%s[%s]", applet_name, seq ? seq : utoa(my_pid));
}
}
/* If it exists, does /dev/mdev.seq match $SEQNUM?
* If it does not match, earlier mdev is running
* in parallel, and we need to wait.
* Active mdev pokes us with SIGCHLD to check the new file.
*/
static int
wait_for_seqfile(unsigned expected_seq)
{
/* We time out after 2 sec */
static const struct timespec ts = { 0, 32*1000*1000 };
int timeout = 2000 / 32;
int seq_fd = -1;
int do_once = 1;
sigset_t set_CHLD;
sigemptyset(&set_CHLD);
sigaddset(&set_CHLD, SIGCHLD);
sigprocmask(SIG_BLOCK, &set_CHLD, NULL);
for (;;) {
int seqlen;
char seqbuf[sizeof(long)*3 + 2];
unsigned seqbufnum;
if (seq_fd < 0) {
seq_fd = open("mdev.seq", O_RDWR);
if (seq_fd < 0)
break;
close_on_exec_on(seq_fd);
}
seqlen = pread(seq_fd, seqbuf, sizeof(seqbuf) - 1, 0);
if (seqlen < 0) {
close(seq_fd);
seq_fd = -1;
break;
}
seqbuf[seqlen] = '\0';
if (seqbuf[0] == '\n' || seqbuf[0] == '\0') {
/* seed file: write out seq ASAP */
xwrite_str(seq_fd, utoa(expected_seq));
xlseek(seq_fd, 0, SEEK_SET);
dbg2("first seq written");
break;
}
seqbufnum = atoll(seqbuf);
if (seqbufnum == expected_seq) {
/* correct idx */
break;
}
if (seqbufnum > expected_seq) {
/* a later mdev runs already (this was seen by users to happen) */
/* do not overwrite seqfile on exit */
close(seq_fd);
seq_fd = -1;
break;
}
if (do_once) {
dbg2("%s mdev.seq='%s', need '%u'", curtime(), seqbuf, expected_seq);
do_once = 0;
}
if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
dbg3("woken up");
continue; /* don't decrement timeout! */
}
if (--timeout == 0) {
dbg1("%s mdev.seq='%s'", "timed out", seqbuf);
break;
}
}
sigprocmask(SIG_UNBLOCK, &set_CHLD, NULL);
return seq_fd;
}
static void signal_mdevs(unsigned my_pid)
{
procps_status_t* p = NULL;
while ((p = procps_scan(p, PSSCAN_ARGV0)) != NULL) {
if (p->pid != my_pid
&& p->argv0
&& strcmp(bb_basename(p->argv0), "mdev") == 0
) {
kill(p->pid, SIGCHLD);
}
}
}
int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mdev_main(int argc UNUSED_PARAM, char **argv)
{
RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
INIT_G();
#if ENABLE_FEATURE_MDEV_CONF
G.filename = "/etc/mdev.conf";
#endif
/* We can be called as hotplug helper */
/* Kernel cannot provide suitable stdio fds for us, do it ourself */
bb_sanitize_stdio();
/* Force the configuration file settings exactly */
umask(0);
xchdir("/dev");
if (argv[1] && strcmp(argv[1], "-s") == 0) {
/*
* Scan: mdev -s
*/
struct stat st;
#if ENABLE_FEATURE_MDEV_CONF
/* Same as xrealloc_vector(NULL, 4, 0): */
G.rule_vec = xzalloc((1 << 4) * sizeof(*G.rule_vec));
#endif
xstat("/", &st);
G.root_major = major(st.st_dev);
G.root_minor = minor(st.st_dev);
putenv((char*)"ACTION=add");
/* Create all devices from /sys/dev hierarchy */
recursive_action("/sys/dev",
ACTION_RECURSE | ACTION_FOLLOWLINKS,
fileAction, dirAction, temp, 0);
} else {
char *fw;
char *seq;
char *action;
char *env_devname;
char *env_devpath;
unsigned my_pid;
unsigned seqnum = seqnum; /* for compiler */
int seq_fd;
smalluint op;
/* Hotplug:
* env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
* ACTION can be "add", "remove", "change"
* DEVPATH is like "/block/sda" or "/class/input/mice"
*/
env_devname = getenv("DEVNAME"); /* can be NULL */
G.subsystem = getenv("SUBSYSTEM");
action = getenv("ACTION");
env_devpath = getenv("DEVPATH");
if (!action || !env_devpath /*|| !G.subsystem*/)
bb_show_usage();
fw = getenv("FIRMWARE");
seq = getenv("SEQNUM");
op = index_in_strings(keywords, action);
my_pid = getpid();
open_mdev_log(seq, my_pid);
seq_fd = -1;
if (seq) {
seqnum = atoll(seq);
seq_fd = wait_for_seqfile(seqnum);
}
dbg1("%s "
"ACTION:%s SUBSYSTEM:%s DEVNAME:%s DEVPATH:%s"
"%s%s",
curtime(),
action, G.subsystem, env_devname, env_devpath,
fw ? " FW:" : "", fw ? fw : ""
);
snprintf(temp, PATH_MAX, "/sys%s", env_devpath);
if (op == OP_remove) {
/* Ignoring "remove firmware". It was reported
* to happen and to cause erroneous deletion
* of device nodes. */
if (!fw)
make_device(env_devname, temp, op);
}
else {
make_device(env_devname, temp, op);
if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
if (op == OP_add && fw)
load_firmware(fw, temp);
}
}
dbg1("%s exiting", curtime());
if (seq_fd >= 0) {
xwrite_str(seq_fd, utoa(seqnum + 1));
signal_mdevs(my_pid);
}
}
if (ENABLE_FEATURE_CLEAN_UP)
RELEASE_CONFIG_BUFFER(temp);
return EXIT_SUCCESS;
}
Reference in New Issue View Git Blame Copy Permalink