* 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 $SUBSYSTEM, extracts
*
* [-][subsystem/]device user:grp mode [>|=path] [@|$|*command args...]
* [-]@maj,min[-min2] user:grp mode [>|=path] [@|$|*command args...]
- *
- * The device name or "subsystem/device" combo is matched against 1st field
- * (which is a regex), or maj,min is matched against 1st field.
+ * [-]$envvar=val user:grp mode [>|=path] [@|$|*command args...]
*
* Leading minus in 1st field means "don't stop on this line", otherwise
* search is stopped after the matching line is encountered.
*
- * When line matches, the device node is created, chmod'ed and chown'ed.
- * Then it moved to path, and if >path, a symlink to moved node is created
+ * The device name or "subsystem/device" combo is matched against 1st field
+ * (which is a regex), or maj,min is matched against 1st field,
+ * or specified environment variable (as regex) is matched against 1st field.
+ *
+ * $envvar=val 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').
+ *
+ * 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.
*/
struct globals {
return alias;
}
-/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
-/* NB: "mdev -s" may call us many times, do not leak memory/fds! */
+/* 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 (IOW: to restore if needed)
+ * path string.
+ * NB2: "mdev -s" may call us many times, do not leak memory/fds!
+ */
static void make_device(char *path, int delete)
{
- const char *device_name;
+ char *device_name;
int major, minor, type, len;
- int mode;
- char *dev_maj_min = path + strlen(path);
+ mode_t mode;
parser_t *parser;
- /* Force the configuration file settings exactly. */
- umask(0);
-
/* 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.
*/
major = -1;
if (!delete) {
+ char *dev_maj_min = path + strlen(path);
+
strcpy(dev_maj_min, "/dev");
len = open_read_close(path, dev_maj_min + 1, 64);
- *dev_maj_min++ = '\0';
+ *dev_maj_min = '\0';
if (len < 1) {
if (!ENABLE_FEATURE_MDEV_EXEC)
return;
- /* no "dev" file, so just try to run script */
- *dev_maj_min = '\0';
- } else if (sscanf(dev_maj_min, "%u:%u", &major, &minor) != 2) {
+ /* no "dev" file, but we can still run scripts
+ * based on device name */
+ } else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) != 2) {
major = -1;
}
}
/* Determine device name, type, major and minor */
- device_name = bb_basename(path);
+ device_name = (char*) bb_basename(path);
/* 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,
parser = config_open2("/etc/mdev.conf", fopen_for_read);
do {
- regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
int keep_matching;
- char *val, *name;
struct bb_uidgid_t ugid;
char *tokens[4];
char *command = NULL;
if (ENABLE_FEATURE_MDEV_CONF
&& config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)
) {
+ char *val;
+ char *str_to_match;
+ regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
+
val = tokens[0];
keep_matching = ('-' == val[0]);
val += keep_matching; /* swallow leading dash */
/* Match against either "subsystem/device_name"
* or "device_name" alone */
- name = strchr(val, '/') ? path : (char *) device_name;
+ str_to_match = strchr(val, '/') ? path : device_name;
/* Fields: regex uid:gid mode [alias] [cmd] */
- /* 1st field: @<numeric maj,min>... */
if (val[0] == '@') {
- /* @major,minor[-last] */
+ /* @major,minor[-minor2] */
/* (useful when name is ambiguous:
* "/sys/class/usb/lp0" and
* "/sys/class/printer/lp0") */
) {
continue; /* this line doesn't match */
}
- } else { /* ... or regex to match device name */
+ goto line_matches;
+ }
+ if (val[0] == '$') {
+ /* regex to match an environment variable */
+ char *eq = strchr(++val, '=');
+ if (!eq)
+ continue;
+ *eq = '\0';
+ str_to_match = getenv(val);
+ if (!str_to_match)
+ continue;
+ str_to_match -= strlen(val) + 1;
+ *eq = '=';
+ }
+ /* else: regex to match [subsystem/]device_name */
+
+ {
regex_t match;
int result;
- /* Is this it? */
xregcomp(&match, val, REG_EXTENDED);
- result = regexec(&match, name, ARRAY_SIZE(off), off, 0);
+ result = regexec(&match, str_to_match, ARRAY_SIZE(off), off, 0);
regfree(&match);
-
//bb_error_msg("matches:");
//for (int i = 0; i < ARRAY_SIZE(off); i++) {
// if (off[i].rm_so < 0) continue;
// device_name + off[i].rm_so);
//}
- /* If not this device, skip rest of line */
+ /* If no match, skip rest of line */
/* (regexec returns whole pattern as "range" 0) */
if (result || off[0].rm_so
- || ((int)off[0].rm_eo != (int)strlen(name))
+ || ((int)off[0].rm_eo != (int)strlen(str_to_match))
) {
continue; /* this line doesn't match */
}
}
-
- /* This line matches: stop parsing the file after parsing
- * the rest of fields unless keep_matching == 1 */
+ line_matches:
+ /* This line matches. Stop parsing after parsing
+ * the rest the line unless keep_matching == 1 */
/* 2nd field: uid:gid - device ownership */
- parse_chown_usergroup_or_die(&ugid, tokens[1]);
+ if (get_uidgid(&ugid, tokens[1], 1) == 0)
+ bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno);
/* 3rd field: mode - device permissions */
- mode = strtoul(tokens[2], NULL, 8);
+ /* mode = strtoul(tokens[2], NULL, 8); */
+ bb_parse_mode(tokens[2], &mode);
val = tokens[3];
/* 4th field (opt): >|=alias */
if (*s++ == '%')
n++;
- p = alias = xzalloc(strlen(a) + n * strlen(name));
+ p = alias = xzalloc(strlen(a) + n * strlen(str_to_match));
s = a + 1;
while (*s) {
*p = *s;
i = (s[1] - '0');
if (i <= 9 && off[i].rm_so >= 0) {
n = off[i].rm_eo - off[i].rm_so;
- strncpy(p, name + off[i].rm_so, n);
+ strncpy(p, str_to_match + off[i].rm_so, n);
p += n - 1;
s++;
}
const char *s = "$@*";
const char *s2 = strchr(s, val[0]);
- if (!s2)
- bb_error_msg_and_die("bad line %u", parser->lineno);
+ if (!s2) {
+ bb_error_msg("bad line %u", parser->lineno);
+ if (ENABLE_FEATURE_MDEV_RENAME)
+ free(alias);
+ continue;
+ }
/* Are we running this command now?
* Run $cmd on delete, @cmd on create, *cmd on both
/* End of field parsing */
/* "Execute" the line we found */
-
- if (!delete && major >= 0) {
- if (ENABLE_FEATURE_MDEV_RENAME)
- unlink(device_name);
- if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
- bb_perror_msg_and_die("mknod %s", device_name);
- if (major == root_major && minor == root_minor)
- symlink(device_name, "root");
- if (ENABLE_FEATURE_MDEV_CONF) {
- chmod(device_name, mode);
- chown(device_name, ugid.uid, ugid.gid);
- }
- if (ENABLE_FEATURE_MDEV_RENAME && alias) {
- alias = build_alias(alias, device_name);
- /* move the device, and optionally
- * make a symlink to moved device node */
- if (rename(device_name, alias) == 0 && aliaslink == '>')
- symlink(alias, device_name);
- free(alias);
+ {
+ const char *node_name;
+
+ node_name = device_name;
+ if (ENABLE_FEATURE_MDEV_RENAME && alias)
+ node_name = alias = build_alias(alias, device_name);
+
+ if (!delete && major >= 0) {
+ if (mknod(node_name, mode | type, makedev(major, minor)) && errno != EEXIST)
+ bb_perror_msg("can't create %s", node_name);
+ if (major == root_major && minor == root_minor)
+ symlink(node_name, "root");
+ if (ENABLE_FEATURE_MDEV_CONF) {
+ chmod(node_name, mode);
+ chown(node_name, ugid.uid, ugid.gid);
+ }
+ if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+ if (aliaslink == '>')
+ 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", device_name);
- char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
- putenv(s);
- putenv(s1);
- if (system(command) == -1)
- bb_perror_msg_and_die("can't run '%s'", command);
- unsetenv("SUBSYSTEM");
- free(s1);
- unsetenv("MDEV");
- free(s);
- free(command);
- }
+ if (ENABLE_FEATURE_MDEV_EXEC && command) {
+ /* setenv will leak memory, use putenv/unsetenv/free */
+ char *s = xasprintf("%s=%s", "MDEV", node_name);
+ char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
+ putenv(s);
+ putenv(s1);
+ if (system(command) == -1)
+ bb_perror_msg("can't run '%s'", command);
+ unsetenv("SUBSYSTEM");
+ free(s1);
+ unsetenv("MDEV");
+ free(s);
+ free(command);
+ }
- if (delete) {
- unlink(device_name);
- /* At creation time, device might have been moved
- * and a symlink might have been created. Undo that. */
+ if (delete) {
+ if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+ if (aliaslink == '>')
+ unlink(device_name);
+ }
+ unlink(node_name);
+ }
- if (ENABLE_FEATURE_MDEV_RENAME && alias) {
- alias = build_alias(alias, device_name);
- unlink(alias);
+ if (ENABLE_FEATURE_MDEV_RENAME)
free(alias);
- }
}
/* We found matching line.
/* 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) {
char *seq;
char *action;
char *env_path;
+ static const char keywords[] ALIGN1 = "remove\0add\0";
+ enum { OP_remove = 0, OP_add };
+ smalluint op;
/* Hotplug:
* env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
if (!action || !env_path /*|| !subsystem*/)
bb_show_usage();
fw = getenv("FIRMWARE");
-
+ op = index_in_strings(keywords, action);
/* 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 */
}
snprintf(temp, PATH_MAX, "/sys%s", env_path);
- if (strcmp(action, "remove") == 0) {
+ if (op == OP_remove) {
/* Ignoring "remove firmware". It was reported
* to happen and to cause erroneous deletion
* of device nodes. */
if (!fw)
make_device(temp, 1);
}
- else if (strcmp(action, "add") == 0) {
+ else if (op == OP_add) {
make_device(temp, 0);
if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
if (fw)
projects / oweals / busybox.git / blobdiff