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logger: Fix inotify + honor the defaults and precedence of various ways to configure options #506

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merged 12 commits into from
Dec 7, 2018
Merged

logger: Fix inotify + honor the defaults and precedence of various ways to configure options #506

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3deee10
logger: check for -1 return value on open
Dec 3, 2018
a32069c
inotify: watch the directory not just file
Dec 3, 2018
790e977
config: cleanup few allocations and naming
Dec 3, 2018
9f427b8
logger-init: honor the defaults when config key:value pair is commented
Nov 30, 2018
dc31d81
config: deprecate tcmu_parse_config
Dec 3, 2018
776a5c4
main: organize the cleanup sequence
Dec 5, 2018
4bbecfe
dyn-logger-config: honor the precedence
Dec 3, 2018
e0e03d0
daemon: log start/exit msgs with crit level
Dec 3, 2018
bbafc08
doc: update readme
Dec 3, 2018
5705305
cmake_install: backup old tcmu.conf version as tcmu.conf.old
Dec 4, 2018
f7b766b
load_config: retry opening conf-file if the initial attempt fail
Dec 4, 2018
ad561ae
logger: skip resetting options if they match with current
Dec 4, 2018
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20 changes: 10 additions & 10 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -140,8 +140,8 @@ backstores.

- Logger setting:

There are 5 logging levels supported:

# There are 6 logging levels supported:
0. CRIT
1. ERROR
2. WARNING
3. INFO
Expand All @@ -153,15 +153,15 @@ uncomment the following line in /etc/tcmu/tcmu.conf and set your level number:

\# log_level = 3

The priority of the logdir setting can be managed via following options:

1. Cli argument
</br>eg: --tcmu_log_dir/-l `LOG_DIR_PATH` [Highest prio]
2. Environment variable
The precedence of the config settings is as mentioned belows:
1. Options set through config file /etc/tcmu/tcmu.conf [Top Prio]
</br>eg: uncommenting and adjusting key:value at /etc/tcmu/tcmu.conf
2. Arguments passed at daemon
</br>eg: -l/--tcmu-log-dir, -d/--debug
3. Environment variable.
</br>eg: export TCMU_LOGDIR="/var/log/mylogdir/"
3. Configuration file
</br>eg: uncommenting and adjusting value of 'log_dir_path' at /etc/tcmu/tcmu.conf
4. Default logdir as hard coded i.e. '/var/log/' [Least prio]
4. Code level defaults. [Least Prio]
</br>eg: TCMU_LOG_DIR_DEFAULT = '/var/log/' & TCMU_CONF_LOG_INFO = INFO

- System configuration:

Expand Down
218 changes: 103 additions & 115 deletions libtcmu_config.c
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -88,11 +88,6 @@ struct tcmu_conf_option {
* TCMU_PARSE_CFG_INT(cfg, log_level);
* TCMU_CONF_CHECK_LOG_LEVEL(log_level);
* }
* 4, Then add your own free method in if it's a STR KEY:
* static void tcmu_conf_free_str_keys(struct tcmu_config *cfg)
* {
* TCMU_FREE_CFG_STR_KEY(cfg, 'STR KEY');
* }
*
* Note: For now, if the options have been changed in config file, the
* system config reload thread daemon will try to update them for all the
Expand All @@ -113,76 +108,89 @@ static struct tcmu_conf_option * tcmu_get_option(const char *key)
return NULL;
}

static struct tcmu_conf_option *
tcmu_register_option(char *key, tcmu_option_type type)
{
struct tcmu_conf_option *option;

option = calloc(1, sizeof(*option));
if (!option)
return NULL;

option->key = strdup(key);
if (!option->key)
goto free_option;
option->type = type;
list_node_init(&option->list);

list_add_tail(&tcmu_options, &option->list);
return option;

free_option:
free(option);
return NULL;
}

/* The default value should be specified here,
* so the next time when users comment out an
* option in config file, here it will set the
* default value back.
*/
#define TCMU_PARSE_CFG_INT(cfg, key, def) \
#define TCMU_PARSE_CFG_INT(cfg, key) \
do { \
struct tcmu_conf_option *option; \
option = tcmu_get_option(#key); \
if (option) { \
if (!option) { \
option = tcmu_register_option(#key, TCMU_OPT_INT); \
cfg->key = cfg->def_##key; \
} else { \
cfg->key = option->opt_int; \
option->opt_int = def; \
} \
option->opt_int = cfg->def_##key;\
} while (0)

#define TCMU_PARSE_CFG_BOOL(cfg, key, def) \
#define TCMU_PARSE_CFG_BOOL(cfg, key) \
do { \
struct tcmu_conf_option *option; \
option = tcmu_get_option(#key); \
if (option) { \
if (!option) { \
option = tcmu_register_option(#key, TCMU_OPT_BOOL); \
cfg->key = cfg->def_##key; \
} else { \
cfg->key = option->opt_bool; \
option->opt_bool = def; \
} \
option->opt_bool = cfg->def_##key; \
} while (0)

#define TCMU_PARSE_CFG_STR(cfg, key, def) \
#define TCMU_PARSE_CFG_STR(cfg, key) \
do { \
struct tcmu_conf_option *option; \
char buf[1024]; \
option = tcmu_get_option(#key); \
if (option) { \
if (cfg->key) \
free(cfg->key); \
cfg->key = strdup(option->opt_str); \
memset(cfg->key, 0, sizeof(cfg->key)); \
if (!option) { \
option = tcmu_register_option(#key, TCMU_OPT_STR); \
snprintf(cfg->key, sizeof(cfg->key), cfg->def_##key); \
} else { \
snprintf(cfg->key, sizeof(cfg->key), option->opt_str); \
if (option->opt_str) \
free(option->opt_str); \
sprintf(buf, "%s", def); \
option->opt_str = strdup(buf); \
} \
} while (0);

#define TCMU_FREE_CFG_STR_KEY(cfg, key) \
do { \
free(cfg->key); \
option->opt_str = strdup(cfg->def_##key); \
} while (0);

static void tcmu_conf_set_options(struct tcmu_config *cfg)
{
/* set log_level option */
TCMU_PARSE_CFG_INT(cfg, log_level, TCMU_CONF_LOG_INFO);
TCMU_PARSE_CFG_INT(cfg, log_level);
tcmu_set_log_level(cfg->log_level);

/* set log_dir path option */
TCMU_PARSE_CFG_STR(cfg, log_dir_path, TCMU_LOG_DIR_DEFAULT);
if (cfg->log_dir_path)
tcmu_resetup_log_file(cfg->log_dir_path);
TCMU_PARSE_CFG_STR(cfg, log_dir);
tcmu_resetup_log_file(cfg->log_dir);

/* add your new config options */
}

static void tcmu_conf_free_str_keys(struct tcmu_config *cfg)
{
/* add your str type config options
*
* For example:
* TCMU_FREE_CFG_STR_KEY(cfg, 'STR KEY');
*/
TCMU_FREE_CFG_STR_KEY(cfg, log_dir_path);
}

#define TCMU_MAX_CFG_FILE_SIZE (2 * 1024 * 1024)
static int tcmu_read_config(int fd, char *buf, int count)
{
Expand Down Expand Up @@ -227,29 +235,6 @@ static int tcmu_read_config(int fd, char *buf, int count)
#define MAX_KEY_LEN 64
#define MAX_VAL_STR_LEN 256

static struct tcmu_conf_option *
tcmu_register_option(char *key, tcmu_option_type type)
{
struct tcmu_conf_option *option;

option = calloc(1, sizeof(*option));
if (!option)
return NULL;

option->key = strdup(key);
if (!option->key)
goto free_option;
option->type = type;
list_node_init(&option->list);

list_add_tail(&tcmu_options, &option->list);
return option;

free_option:
free(option);
return NULL;
}

static void tcmu_parse_option(char **cur, const char *end)
{
struct tcmu_conf_option *option;
Expand Down Expand Up @@ -365,18 +350,27 @@ static void tcmu_parse_options(struct tcmu_config *cfg, char *buf, int len)
tcmu_conf_set_options(cfg);
}

static int tcmu_load_config(struct tcmu_config *cfg)
int tcmu_load_config(struct tcmu_config *cfg)
{
int ret = -1;
int fd, len;
char *buf;
int i;

buf = malloc(TCMU_MAX_CFG_FILE_SIZE);
if (!buf)
return -ENOMEM;

fd = open(cfg->path, O_RDONLY);
if (fd < 0) {
for (i = 0; i < 5; i++) {
if ((fd = open(cfg->path, O_RDONLY)) == -1) {
/* give a moment for editor to restore
* the conf-file after edit and save */
sleep(1);
continue;
}
break;
}
if (fd == -1) {
tcmu_err("Failed to open file '%s', %m\n", cfg->path);
goto free_buf;
}
Expand Down Expand Up @@ -404,101 +398,97 @@ static void *dyn_config_start(void *arg)
struct tcmu_config *cfg = arg;
int monitor, wd, len;
char buf[BUF_LEN];
char cfg_dir[PATH_MAX];
char *p;

monitor = inotify_init();
if (monitor == -1) {
tcmu_err("Failed to init inotify %m\n");
return NULL;
}

wd = inotify_add_watch(monitor, cfg->path, IN_ALL_EVENTS);
snprintf(cfg_dir, PATH_MAX, cfg->path);
p = strrchr(cfg_dir, '/');
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Before it will allowed us to use /AA/BB, but now only /AA/BB/ is allowed.
Is this okay ?

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That shouldn't be a problem, ending the directory name with '/' makes it readable.

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okay.

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BTW - this is just conf file's dir path, not the log_dir path.

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yeah.

if (p) {
*(p + 1) = '\0';
} else {
snprintf(cfg_dir, PATH_MAX, "/etc/tcmu/");
}

/* Editors (vim, nano ..) follow different approaches to save conf file.
* The two commonly followed techniques are to overwrite the existing
* file, or to write to a new file (.swp, .tmp ..) and move it to actual
* file name later. In the later case, the inotify fails, because the
* file it's been intended to watch no longer exists, as the new file
* is a different file with just a same name.
* To handle both the file save approaches mentioned above, it is better
* we watch the directory and filter for MODIFY events.
*/
wd = inotify_add_watch(monitor, cfg_dir, IN_MODIFY);
if (wd == -1) {
tcmu_err("Failed to add \"%s\" to inotify %m\n", cfg->path);
tcmu_err("Failed to add \"%s\" to inotify %m\n", cfg_dir);
return NULL;
}

tcmu_info("Inotify is watching \"%s\", wd: %d, mask: IN_ALL_EVENTS\n",
cfg->path, wd);
tcmu_info("Inotify is watching \"%s\", wd: %d, mask: IN_MODIFY\n",
cfg_dir, wd);


while (1) {
struct inotify_event *event;
char *p;

len = read(monitor, buf, BUF_LEN);
if (len == -1) {
tcmu_warn("Failed to read inotify: %m\n");
continue;
}

for (p = buf; p < buf + len;) {
for (p = buf; p < buf + len;
p += sizeof(struct inotify_event) + event->len) {
event = (struct inotify_event *)p;

tcmu_info("event->mask: 0x%x\n", event->mask);

if (event->wd != wd)
continue;

/*
* If force to write to the unwritable or crashed
* config file, the vi/vim will try to move and
* delete the config file and then recreate it again
* via the *.swp
*/
if ((event->mask & IN_IGNORED) && !access(cfg->path, F_OK))
wd = inotify_add_watch(monitor, cfg->path, IN_ALL_EVENTS);

/* Try to reload the config file */
if (event->mask & IN_MODIFY || event->mask & IN_IGNORED)
if (event->mask & IN_MODIFY)
tcmu_load_config(cfg);

p += sizeof(struct inotify_event) + event->len;
}
}

return NULL;
}

struct tcmu_config *tcmu_parse_config(const char *path)
int tcmu_watch_config(struct tcmu_config *cfg)
{
return pthread_create(&cfg->thread_id, NULL, dyn_config_start, cfg);
}

void tcmu_unwatch_config(struct tcmu_config *cfg)
{
tcmu_thread_cancel(cfg->thread_id);
}

struct tcmu_config* tcmu_initialize_config(void)
{
struct tcmu_config *cfg;
char *log_dir;

cfg = calloc(1, sizeof(*cfg));
if (cfg == NULL) {
tcmu_err("Alloc TCMU config failed!\n");
tcmu_err("allocating TCMU config failed: %m\n");
errno = ENOMEM;
return NULL;
}

if (!path)
path = "/etc/tcmu/tcmu.conf"; /* the default config file */

cfg->path = strdup(path);
if (!cfg->path) {
tcmu_err("failed to copy path: %s\n", path);
goto free_cfg;
}

if (tcmu_load_config(cfg)) {
tcmu_err("Loading TCMU config failed!\n");
goto free_path;
}
log_dir = getenv("TCMU_LOGDIR");
snprintf(cfg->def_log_dir, PATH_MAX, log_dir ? log_dir : TCMU_LOG_DIR_DEFAULT);
cfg->def_log_level = TCMU_CONF_LOG_INFO;
snprintf(cfg->path, PATH_MAX, TCMU_CONFIGFILE_DEFAULT);

return cfg;

free_path:
free(cfg->path);
free_cfg:
free(cfg);
return NULL;
}

int tcmu_watch_config(struct tcmu_config *cfg)
{
return pthread_create(&cfg->thread_id, NULL, dyn_config_start, cfg);
}

void tcmu_unwatch_config(struct tcmu_config *cfg)
{
tcmu_thread_cancel(cfg->thread_id);
}

void tcmu_free_config(struct tcmu_config *cfg)
Expand All @@ -517,7 +507,5 @@ void tcmu_free_config(struct tcmu_config *cfg)
free(option);
}

tcmu_conf_free_str_keys(cfg);
free(cfg->path);
free(cfg);
}
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