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authorDenys Vlasenko <vda.linux@googlemail.com>2013-02-27 09:51:41 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2013-02-27 09:51:41 (GMT)
commit5bce135e36800a34a273376d5ea1f052ed2d4212 (patch)
tree00a35271b59d2e6e029555296ff6e0ee79451e30
parent9fed24c031a885264a9249eed3b6c654c32ce139 (diff)
downloadbusybox-5bce135e36800a34a273376d5ea1f052ed2d4212.tar.gz
busybox-5bce135e36800a34a273376d5ea1f052ed2d4212.tar.bz2
mdev: improve $SEQ handling; improve debug logging
Sequential run of concurrent mdev's was too simplistic: they waited for /dev/mdev.seq to match. This could sometimes cause cumulative loss of time on the order of a second. Added SIGCHLD signaling from exiting mdev to all other mdev's. Added debugging required to see that code actually works as intended. Example of /dev/mdev.log (with "woken up" elevated from dbg lvl 3 to 2): mdev[1023]: first seq written ^^^^ seq, not pid mdev[1023]: 35.022395 ACTION:add SUBSYSTEM:module DEVNAME:(null) DEVPATH:/module/lib80211 mdev[1023]: rule matched, line -1 ^^^^^^^ means "default rule" mdev[1023]: 35.022676 exiting ^^^^^^^^^ second,usec timestamp mdev[1024]: 35.069691 ACTION:add SUBSYSTEM:vc DEVNAME:vcs9 DEVPATH:/devices/virtual/vc/vcs9 mdev[1024]: dev 7,9 mdev[1025]: 35.069889 waiting for '1024' mdev[1026]: 35.069946 waiting for '1024' mdev[1027]: 35.070151 waiting for '1024' mdev[1024]: rule matched, line -1 mdev[1024]: mknod vcs9 (7,9) 20660 0:0 mdev[1024]: 35.070346 exiting mdev[1025]: woken up mdev[1026]: woken up mdev[1025]: 35.071213 ACTION:add SUBSYSTEM:vc DEVNAME:vcsa9 DEVPATH:/devices/virtual/vc/vcsa9 ^^^^^^^^^ took only a millisecond to start running after prev mdev exited mdev[1025]: dev 7,137 mdev[1027]: woken up mdev[1025]: rule matched, line -1 mdev[1025]: mknod vcsa9 (7,137) 20660 0:0 mdev[1025]: 35.072109 exiting function old new delta mdev_main 849 1372 +523 curtime - 59 +59 dirAction 87 134 +47 static.ts - 8 +8 keywords 19 12 -7 make_device 2189 2119 -70 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--examples/mdev_fat.conf7
-rw-r--r--util-linux/mdev.c265
2 files changed, 181 insertions, 91 deletions
diff --git a/examples/mdev_fat.conf b/examples/mdev_fat.conf
index ceba3a7..bceddb2 100644
--- a/examples/mdev_fat.conf
+++ b/examples/mdev_fat.conf
@@ -7,9 +7,9 @@
# instead of the default 0:0 660.
#
# Syntax:
-# [-]devicename_regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
-# [-]$ENVVAR=regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
-# [-]@maj,min[-min2] user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
+# [-][ENVVAR=regex;]...devicename_regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
+# [-][ENVVAR=regex;]...@maj,min[-min2] user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
+# [-]$ENVVAR=regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
#
# [-]: do not stop on this match, continue reading mdev.conf
# =: move, >: move and create a symlink
@@ -53,6 +53,7 @@ sr[0-9]* root:cdrom 660 @ln -sf $MDEV cdrom
fd[0-9]* root:floppy 660
# net devices
+SUBSYSTEM=net;.* root:root 600 @nameif
tun[0-9]* root:root 600 =net/
tap[0-9]* root:root 600 =net/
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 775e5c2..c5c0d61 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -230,7 +230,26 @@
* SUBSYSTEM=block
*/
-static const char keywords[] ALIGN1 = "add\0remove\0change\0";
+#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 {
@@ -256,6 +275,7 @@ 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;
@@ -263,6 +283,7 @@ struct globals {
unsigned rule_idx;
#endif
struct rule cur_rule;
+ char timestr[sizeof("60.123456")];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
@@ -277,13 +298,6 @@ struct globals {
/* We use additional 64+ bytes in make_device() */
#define SCRATCH_SIZE 80
-#if 0
-# define dbg(...) bb_error_msg(__VA_ARGS__)
-#else
-# define dbg(...) ((void)0)
-#endif
-
-
#if ENABLE_FEATURE_MDEV_CONF
static void make_default_cur_rule(void)
@@ -349,7 +363,7 @@ static void parse_next_rule(void)
break;
/* Fields: [-]regex uid:gid mode [alias] [cmd] */
- dbg("token1:'%s'", tokens[1]);
+ dbg3("token1:'%s'", tokens[1]);
/* 1st field */
val = tokens[0];
@@ -417,7 +431,7 @@ static void parse_next_rule(void)
clean_up_cur_rule();
} /* while (config_read) */
- dbg("config_close(G.parser)");
+ dbg3("config_close(G.parser)");
config_close(G.parser);
G.parser = NULL;
@@ -434,7 +448,7 @@ static const struct rule *next_rule(void)
/* Open conf file if we didn't do it yet */
if (!G.parser && G.filename) {
- dbg("config_open('%s')", G.filename);
+ dbg3("config_open('%s')", G.filename);
G.parser = config_open2(G.filename, fopen_for_read);
G.filename = NULL;
}
@@ -443,7 +457,7 @@ static const struct rule *next_rule(void)
/* mdev -s */
/* Do we have rule parsed already? */
if (G.rule_vec[G.rule_idx]) {
- dbg("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, 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();
@@ -460,7 +474,7 @@ static const struct rule *next_rule(void)
rule = memcpy(xmalloc(sizeof(G.cur_rule)), &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;
- dbg("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
+ dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
}
}
@@ -538,9 +552,6 @@ static void make_device(char *device_name, char *path, int operation)
{
int major, minor, type, len;
- if (G.verbose)
- bb_error_msg("device: %s, %s", device_name, 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.
@@ -559,8 +570,7 @@ static void make_device(char *device_name, char *path, int operation)
/* no "dev" file, but we can still run scripts
* based on device name */
} else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) == 2) {
- if (G.verbose)
- bb_error_msg("maj,min: %u,%u", major, minor);
+ dbg1("dev %u,%u", major, minor);
} else {
major = -1;
}
@@ -570,7 +580,8 @@ static void make_device(char *device_name, char *path, int operation)
/* Determine device name, type, major and minor */
if (!device_name)
device_name = (char*) bb_basename(path);
- /* http://kernel.org/doc/pending/hotplug.txt says that only
+ /*
+ * 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.
@@ -608,7 +619,7 @@ static void make_device(char *device_name, char *path, int operation)
}
if (rule->envvar) { /* $envvar=regex rule */
str_to_match = getenv(rule->envvar);
- dbg("getenv('%s'):'%s'", rule->envvar, str_to_match);
+ dbg3("getenv('%s'):'%s'", rule->envvar, str_to_match);
if (!str_to_match)
continue;
}
@@ -616,7 +627,7 @@ static void make_device(char *device_name, char *path, int operation)
if (rule->regex_compiled) {
int regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0);
- dbg("regex_match for '%s':%d", str_to_match, regex_match);
+ dbg3("regex_match for '%s':%d", str_to_match, regex_match);
//bb_error_msg("matches:");
//for (int i = 0; i < ARRAY_SIZE(off); i++) {
// if (off[i].rm_so < 0) continue;
@@ -636,7 +647,7 @@ static void make_device(char *device_name, char *path, int operation)
/* else: it's final implicit "match-all" rule */
rule_matches:
#endif
- dbg("rule matched");
+ dbg2("rule matched, line %d", G.parser ? G.parser->lineno : -1);
/* Build alias name */
alias = NULL;
@@ -680,34 +691,30 @@ static void make_device(char *device_name, char *path, int operation)
}
}
}
- dbg("alias:'%s'", alias);
+ dbg3("alias:'%s'", alias);
command = NULL;
IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
if (command) {
- const char *s = "$@*";
- const char *s2 = strchr(s, command[0]);
-
/* Are we running this command now?
- * Run $cmd on delete, @cmd on create, *cmd on both
+ * Run @cmd on create, $cmd on delete, *cmd on any
*/
- if (s2 - s != (operation == OP_remove) || *s2 == '*') {
- /* We are here if: '*',
- * or: '@' and delete = 0,
- * or: '$' and delete = 1
- */
+ if ((command[0] == '@' && operation == OP_add)
+ || (command[0] == '$' && operation == OP_remove)
+ || (command[0] == '*')
+ ) {
command++;
} else {
command = NULL;
}
}
- dbg("command:'%s'", command);
+ 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);
- dbg("alias2:'%s'", alias);
+ dbg3("alias2:'%s'", alias);
}
if (operation == OP_add && major >= 0) {
@@ -717,13 +724,20 @@ static void make_device(char *device_name, char *path, int operation)
mkdir_recursive(node_name);
*slash = '/';
}
- if (G.verbose)
- bb_error_msg("mknod: %s (%d,%d) %o", node_name, major, minor, rule->mode | type);
+ 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) {
- if (G.verbose)
- bb_error_msg("chmod: %o chown: %u:%u", rule->mode, rule->ugid.uid, rule->ugid.gid);
chmod(node_name, rule->mode);
chown(node_name, rule->ugid.uid, rule->ugid.gid);
}
@@ -734,8 +748,7 @@ static void make_device(char *device_name, char *path, int operation)
//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?
- if (G.verbose)
- bb_error_msg("symlink: %s", device_name);
+ dbg1("symlink: %s", device_name);
symlink(node_name, device_name);
}
}
@@ -744,27 +757,21 @@ static void make_device(char *device_name, char *path, int operation)
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", G.subsystem);
putenv(s);
- putenv(s1);
- if (G.verbose)
- bb_error_msg("running: %s", command);
+ dbg1("running: %s", command);
if (system(command) == -1)
bb_perror_msg("can't run '%s'", command);
- bb_unsetenv_and_free(s1);
bb_unsetenv_and_free(s);
}
if (operation == OP_remove && major >= -1) {
if (ENABLE_FEATURE_MDEV_RENAME && alias) {
if (aliaslink == '>') {
- if (G.verbose)
- bb_error_msg("unlink: %s", device_name);
+ dbg1("unlink: %s", device_name);
unlink(device_name);
}
}
- if (G.verbose)
- bb_error_msg("unlink: %s", node_name);
+ dbg1("unlink: %s", node_name);
unlink(node_name);
}
@@ -809,10 +816,15 @@ static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
* under /sys/class/ */
if (1 == depth) {
free(G.subsystem);
+ if (G.subsys_env) {
+ bb_unsetenv_and_free(G.subsys_env);
+ G.subsys_env = NULL;
+ }
G.subsystem = strrchr(fileName, '/');
if (G.subsystem) {
G.subsystem = xstrdup(G.subsystem + 1);
- xsetenv("SUBSYSTEM", G.subsystem);
+ G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
+ putenv(G.subsys_env);
}
}
@@ -885,6 +897,100 @@ static void load_firmware(const char *firmware, const char *sysfs_path)
}
}
+static char *curtime(void)
+{
+ struct timeval tv;
+ gettimeofday(&tv, NULL);
+ sprintf(G.timestr, "%u.%06u", (unsigned)tv.tv_sec % 60, (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(const char *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(int)*3 + 2];
+
+ if (seq_fd < 0) {
+ seq_fd = open("mdev.seq", O_RDWR);
+ if (seq_fd < 0)
+ break;
+ }
+ 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') {
+ /* seed file: write out seq ASAP */
+ xwrite_str(seq_fd, seq);
+ xlseek(seq_fd, 0, SEEK_SET);
+ dbg2("first seq written");
+ break;
+ }
+ if (strcmp(seq, seqbuf) == 0) {
+ /* correct idx */
+ break;
+ }
+ if (do_once) {
+ dbg2("%s waiting for '%s'", curtime(), seqbuf);
+ do_once = 0;
+ }
+ if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
+ dbg3("woken up");
+ continue; /* don't decrement timeout! */
+ }
+ if (--timeout == 0) {
+ dbg1("%s waiting for '%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)
{
@@ -946,11 +1052,13 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
char *action;
char *env_devname;
char *env_devpath;
+ unsigned my_pid;
+ int seq_fd;
smalluint op;
/* Hotplug:
* env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
- * ACTION can be "add" or "remove"
+ * ACTION can be "add", "remove", "change"
* DEVPATH is like "/block/sda" or "/class/input/mice"
*/
action = getenv("ACTION");
@@ -961,41 +1069,20 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
if (!action || !env_devpath /*|| !G.subsystem*/)
bb_show_usage();
fw = getenv("FIRMWARE");
- /* 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 */
seq = getenv("SEQNUM");
- if (seq) {
- int timeout = 2000 / 32; /* 2000 msec */
- do {
- int seqlen;
- char seqbuf[sizeof(int)*3 + 2];
-
- seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf) - 1);
- if (seqlen < 0) {
- seq = NULL;
- break;
- }
- seqbuf[seqlen] = '\0';
- if (seqbuf[0] == '\n' /* seed file? */
- || strcmp(seq, seqbuf) == 0 /* correct idx? */
- ) {
- break;
- }
- usleep(32*1000);
- } while (--timeout);
- }
- {
- int logfd = open("mdev.log", O_WRONLY | O_APPEND);
- if (logfd >= 0) {
- xmove_fd(logfd, STDERR_FILENO);
- G.verbose = 1;
- if (seq)
- applet_name = xasprintf("%s[%s]", applet_name, seq);
- bb_error_msg("action: %s", action);
- }
- }
+ my_pid = getpid();
+ open_mdev_log(seq, my_pid);
+
+ seq_fd = seq ? wait_for_seqfile(seq) : -1;
+
+ 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) {
@@ -1005,16 +1092,18 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
if (!fw)
make_device(env_devname, temp, op);
}
- else if (op == OP_add) {
+ else {
make_device(env_devname, temp, op);
if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
- if (fw)
+ if (op == OP_add && fw)
load_firmware(fw, temp);
}
}
- if (seq) {
- xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
+ dbg1("%s exiting", curtime());
+ if (seq_fd >= 0) {
+ xwrite_str(seq_fd, utoa(xatou(seq) + 1));
+ signal_mdevs(my_pid);
}
}