autofs-5.1.2 - create thread-local ID for mount attempts

From: Lars R. Damerow <lars@pixar.com>

This patch creates key_thread_attempt_id as a pthread key and populates it

in each new thread serving a mount attempt. This ID can be used in output logs

as an easy string to grep for, allowing admins to quickly see a mount attempt's

log entries without the messages from other attempts interleaved.

The contents of the ID are intended to be opaque, but to get a chance at

a unique value for each mount attempt, this patch does a very simple hash

computation of the thread's wait_queue_token, the pid of the requesting

process, and the key for the mount. The hash is based on the public domain

sdbm library.

Signed-off-by: Lars R. Damerow <lars@pixar.com>

Signed-off-by: Ian Kent <raven@themaw.net>

---

 CHANGELOG           |    1 +

 daemon/automount.c  |   24 ++++++++++++++++++++++++

 daemon/direct.c     |   17 +++++++++++++++++

 daemon/indirect.c   |   17 +++++++++++++++++

 include/automount.h |    6 ++++++

 5 files changed, 65 insertions(+)

--- autofs-5.0.7.orig/CHANGELOG

+++ autofs-5.0.7/CHANGELOG

@@ -236,6 +236,7 @@

 - fix bogus check in expire_cleanup().

 - delay submount exit for amd submounts.

 - add the mount requestor's pid to pending_args.

+- create thread-local ID for mount attempts.

 25/07/2012 autofs-5.0.7

 =======================

--- autofs-5.0.7.orig/daemon/automount.c

+++ autofs-5.0.7/daemon/automount.c

@@ -89,6 +89,7 @@ struct startup_cond suc = {

 	PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0};

 pthread_key_t key_thread_stdenv_vars;

+pthread_key_t key_thread_attempt_id = (pthread_key_t) 0L;

 #define MAX_OPEN_FILES		10240

@@ -98,6 +99,17 @@ static int umount_all(struct autofs_poin

 extern struct master *master_list;

+/* simple string hash based on public domain sdbm library */

+unsigned long sdbm_hash(const char *str, unsigned long seed)

+{

+	unsigned long hash = seed;

+	char c;

+

+	while ((c = *str++))

+		hash = c + (hash << 6) + (hash << 16) - hash;

+	return hash;

+}

+

 static int do_mkdir(const char *parent, const char *path, mode_t mode)

 {

 	int status;

@@ -2441,6 +2453,18 @@ int main(int argc, char *argv[])

 		       program);

 		master_kill(master_list);

 		res = write(start_pipefd[1], pst_stat, sizeof(*pst_stat));

+		close(start_pipefd[1]);

+		release_flag_file();

+		macro_free_global_table();

+		exit(1);

+	}

+

+	status = pthread_key_create(&key_thread_attempt_id, free);

+	if (status) {

+		logerr("%s: failed to create thread data key for attempt ID!",

+		       program);

+		master_kill(master_list);

+		res = write(start_pipefd[1], pst_stat, sizeof(*pst_stat));

 		close(start_pipefd[1]);

 		release_flag_file();

 		macro_free_global_table();

--- autofs-5.0.7.orig/daemon/direct.c

+++ autofs-5.0.7/daemon/direct.c

@@ -1210,6 +1210,8 @@ static void *do_mount_direct(void *arg)

 	struct autofs_point *ap;

 	struct stat st;

 	int status, state;

+	char attempt_id_comp[20];

+	unsigned long *attempt_id;

 	args = (struct pending_args *) arg;

@@ -1219,6 +1221,21 @@ static void *do_mount_direct(void *arg)

 	ap = mt.ap;

+	attempt_id = pthread_getspecific(key_thread_attempt_id);

+	if (attempt_id == NULL) {

+		attempt_id = (unsigned long *) calloc(1, sizeof(unsigned long));

+		if (attempt_id == NULL)

+			fatal(ENOMEM);

+		snprintf(attempt_id_comp, 20, "%ld", mt.wait_queue_token);

+		*attempt_id = sdbm_hash(attempt_id_comp, 0);

+		snprintf(attempt_id_comp, 20, "%u", mt.pid);

+		*attempt_id = sdbm_hash(attempt_id_comp, *attempt_id);

+		*attempt_id = sdbm_hash(mt.name, *attempt_id);

+		status = pthread_setspecific(key_thread_attempt_id, attempt_id);

+		if (status != 0)

+			fatal(status);

+	}

+

 	args->signaled = 1;

 	status = pthread_cond_signal(&args->cond);

 	if (status)

--- autofs-5.0.7.orig/daemon/indirect.c

+++ autofs-5.0.7/daemon/indirect.c

@@ -726,6 +726,8 @@ static void *do_mount_indirect(void *arg

 	char buf[PATH_MAX + 1];

 	struct stat st;

 	int len, status, state;

+	char attempt_id_comp[20];

+	unsigned long *attempt_id;

 	args = (struct pending_args *) arg;

@@ -735,6 +737,21 @@ static void *do_mount_indirect(void *arg

 	ap = mt.ap;

+	attempt_id = pthread_getspecific(key_thread_attempt_id);

+	if (attempt_id == NULL) {

+		attempt_id = (unsigned long *) calloc(1, sizeof(unsigned long));

+		if (attempt_id  == NULL)

+			fatal(ENOMEM);

+		snprintf(attempt_id_comp, 20, "%ld", mt.wait_queue_token);

+		*attempt_id = sdbm_hash(attempt_id_comp, 0);

+		snprintf(attempt_id_comp, 20, "%u", mt.pid);

+		*attempt_id = sdbm_hash(attempt_id_comp, *attempt_id);

+		*attempt_id = sdbm_hash(mt.name, *attempt_id);

+		status = pthread_setspecific(key_thread_attempt_id, attempt_id);

+		if (status != 0)

+			fatal(status);

+	}

+

 	args->signaled = 1;

 	status = pthread_cond_signal(&args->cond);

 	if (status)

--- autofs-5.0.7.orig/include/automount.h

+++ autofs-5.0.7/include/automount.h

@@ -76,6 +76,8 @@ int load_autofs4_module(void);

 #define SMB_SUPER_MAGIC    0x0000517BL

 #define CIFS_MAGIC_NUMBER  0xFF534D42L

+#define ATTEMPT_ID_SIZE 24

+

 /* This sould be enough for at least 20 host aliases */

 #define HOST_ENT_BUF_SIZE	2048

@@ -241,6 +243,8 @@ const char **copy_argv(int argc, const c

 int compare_argv(int argc1, const char **argv1, int argc2, const char **argv2);

 int free_argv(int argc, const char **argv);

+unsigned long sdbm_hash(const char *str, unsigned long seed);

+

 void dump_core(void);

 int aquire_lock(void);

 void release_lock(void);

@@ -480,6 +484,8 @@ struct thread_stdenv_vars {

 extern pthread_key_t key_thread_stdenv_vars;

+extern pthread_key_t key_thread_attempt_id;

+

 struct kernel_mod_version {

 	unsigned int major;

 	unsigned int minor;