logs: introduce a thread-local 'current' lxc_config

src/lxc/Makefile.am

@@ -248,6 +248,7 @@ endif
 
 init_lxc_static_LDFLAGS = -static
 init_lxc_static_LDADD = @CAP_LIBS@
+init_lxc_static_CFLAGS = $(AM_CFLAGS) -DNO_LXC_CONF
 endif
 
 install-exec-local: install-soPROGRAMS

src/lxc/conf.c

@@ -178,6 +178,17 @@ struct caps_opt {
 	int value;
 };
 
+/*
+ * The lxc_conf of the container currently being worked on in an
+ * API call
+ * This is used in the error calls
+ */
+#ifdef HAVE_TLS
+__thread struct lxc_conf *current_config;
+#else
+struct lxc_conf *current_config;
+#endif
+
 /* Declare this here, since we don't want to reshuffle the whole file. */
 static int in_caplist(int cap, struct lxc_list *caps);
 
@@ -2563,6 +2574,7 @@ struct lxc_conf *lxc_conf_init(void)
 		return NULL;
 	}
 	new->kmsg = 0;
+	new->logfd = -1;
 	lxc_list_init(&new->cgroup);
 	lxc_list_init(&new->network);
 	lxc_list_init(&new->mount_list);
@@ -4236,6 +4248,8 @@ void lxc_conf_free(struct lxc_conf *conf)
 	free(conf->rootfs.path);
 	free(conf->rootfs.pivot);
 	free(conf->logfile);
+	if (conf->logfd != -1)
+		close(conf->logfd);
 	free(conf->utsname);
 	free(conf->ttydir);
 	free(conf->fstab);

src/lxc/conf.h

@@ -335,6 +335,7 @@ struct lxc_conf {
 	// store the config file specified values here.
 	char *logfile;  // the logfile as specifed in config
 	int loglevel;   // loglevel as specifed in config (if any)
+	int logfd;
 
 	int inherit_ns_fd[LXC_NS_MAX];
 
@@ -364,6 +365,12 @@ struct lxc_conf {
 	char *init_cmd;
 };
 
+#ifdef HAVE_TLS
+extern __thread struct lxc_conf *current_config;
+#else
+extern struct lxc_conf *current_config;
+#endif
+
 int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf,
 		  const char *lxcpath, char *argv[]);
 

src/lxc/confile.c

@@ -1171,15 +1171,15 @@ static int config_lsm_se_context(const char *key, const char *value,
 }
 
 static int config_logfile(const char *key, const char *value,
-			     struct lxc_conf *lxc_conf)
+			     struct lxc_conf *c)
 {
 	int ret;
 
 	// store these values in the lxc_conf, and then try to set for
 	// actual current logging.
-	ret = config_path_item(&lxc_conf->logfile, value);
+	ret = config_path_item(&c->logfile, value);
 	if (ret == 0)
-		ret = lxc_log_set_file(lxc_conf->logfile);
+		ret = lxc_log_set_file(&c->logfd, c->logfile);
 	return ret;
 }
 
@@ -1198,7 +1198,7 @@ static int config_loglevel(const char *key, const char *value,
 	// store these values in the lxc_conf, and then try to set for
 	// actual current logging.
 	lxc_conf->loglevel = newlevel;
-	return lxc_log_set_level(newlevel);
+	return lxc_log_set_level(&lxc_conf->loglevel, newlevel);
 }
 
 static int config_autodev(const char *key, const char *value,
@@ -2381,9 +2381,9 @@ int lxc_get_config_item(struct lxc_conf *c, const char *key, char *retv,
 	else if (strcmp(key, "lxc.se_context") == 0)
 		v = c->lsm_se_context;
 	else if (strcmp(key, "lxc.logfile") == 0)
-		v = lxc_log_get_file();
+		v = c->logfile;
 	else if (strcmp(key, "lxc.loglevel") == 0)
-		v = lxc_log_priority_to_string(lxc_log_get_level());
+		v = lxc_log_priority_to_string(c->loglevel);
 	else if (strcmp(key, "lxc.cgroup") == 0) // all cgroup info
 		return lxc_get_cgroup_entry(c, retv, inlen, "all");
 	else if (strncmp(key, "lxc.cgroup.", 11) == 0) // specific cgroup info

src/lxc/log.c

@@ -27,6 +27,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <string.h>
+#include <pthread.h>
 
 #define __USE_GNU /* for *_CLOEXEC */
 
@@ -40,27 +41,44 @@
 #define LXC_LOG_PREFIX_SIZE	32
 #define LXC_LOG_BUFFER_SIZE	512
 
-#ifdef HAVE_TLS
-__thread int lxc_log_fd = -1;
-static __thread char log_prefix[LXC_LOG_PREFIX_SIZE] = "lxc";
-static __thread char *log_fname = NULL;
-/* command line values for logfile or logpriority should always override
- * values from the configuration file or defaults
- */
-static __thread int lxc_logfile_specified = 0;
-static __thread int lxc_loglevel_specified = 0;
-static __thread int lxc_quiet_specified = 0;
-#else
+static pthread_mutex_t log_mutex = PTHREAD_MUTEX_INITIALIZER;
+static void lock_mutex(pthread_mutex_t *l)
+{
+	int ret;
+
+	if ((ret = pthread_mutex_lock(l)) != 0) {
+		fprintf(stderr, "pthread_mutex_lock returned:%d %s\n", ret, strerror(ret));
+		exit(1);
+	}
+}
+
+static void unlock_mutex(pthread_mutex_t *l)
+{
+	int ret;
+
+	if ((ret = pthread_mutex_unlock(l)) != 0) {
+		fprintf(stderr, "pthread_mutex_unlock returned:%d %s\n", ret, strerror(ret));
+		exit(1);
+	}
+}
+
+void log_lock(void)
+{
+	lock_mutex(&log_mutex);
+}
+
+void log_unlock(void)
+{
+	unlock_mutex(&log_mutex);
+}
+
 int lxc_log_fd = -1;
+int lxc_quiet_specified;
+int lxc_log_use_global_fd;
+static int lxc_loglevel_specified;
+
 static char log_prefix[LXC_LOG_PREFIX_SIZE] = "lxc";
 static char *log_fname = NULL;
-static int lxc_quiet_specified = 0;
-/* command line values for logfile or logpriority should always override
- * values from the configuration file or defaults
- */
-static int lxc_logfile_specified = 0;
-static int lxc_loglevel_specified = 0;
-#endif
 
 lxc_log_define(lxc_log, lxc);
 
@@ -85,8 +103,17 @@ static int log_append_logfile(const struct lxc_log_appender *appender,
 	char buffer[LXC_LOG_BUFFER_SIZE];
 	int n;
 	int ms;
+	int fd_to_use = -1;
 
-	if (lxc_log_fd == -1)
+#ifndef NO_LXC_CONF
+	if (!lxc_log_use_global_fd && current_config)
+		fd_to_use = current_config->logfd;
+#endif
+
+	if (fd_to_use == -1)
+		fd_to_use = lxc_log_fd;
+
+	if (fd_to_use == -1)
 		return 0;
 
 	ms = event->timestamp.tv_usec / 1000;
@@ -111,7 +138,7 @@ static int log_append_logfile(const struct lxc_log_appender *appender,
 
 	buffer[n] = '\n';
 
-	return write(lxc_log_fd, buffer, n + 1);
+	return write(fd_to_use, buffer, n + 1);
 }
 
 static struct lxc_log_appender log_appender_stderr = {
@@ -136,7 +163,7 @@ static struct lxc_log_category log_root = {
 struct lxc_log_category lxc_log_category_lxc = {
 	.name		= "lxc",
 	.priority	= LXC_LOG_PRIORITY_ERROR,
-	.appender	= &log_appender_stderr,
+	.appender	= &log_appender_logfile,
 	.parent		= &log_root
 };
 
@@ -305,6 +332,11 @@ static int _lxc_log_set_file(const char *name, const char *lxcpath, int create_d
 	return ret;
 }
 
+/*
+ * lxc_log_init:
+ * Called from lxc front-end programs (like lxc-create, lxc-start) to
+ * initalize the log defaults.
+ */
 extern int lxc_log_init(const char *name, const char *file,
 			const char *priority, const char *prefix, int quiet,
 			const char *lxcpath)
@@ -320,10 +352,12 @@ extern int lxc_log_init(const char *name, const char *file,
 	if (priority)
 		lxc_priority = lxc_log_priority_to_int(priority);
 
-	lxc_log_category_lxc.priority = lxc_priority;
+	if (!lxc_loglevel_specified) {
+		lxc_log_category_lxc.priority = lxc_priority;
+		lxc_loglevel_specified = 1;
+	}
 
 	if (!lxc_quiet_specified) {
-		lxc_log_category_lxc.appender = &log_appender_logfile;
 		if (!quiet)
 			lxc_log_category_lxc.appender->next = &log_appender_stderr;
 	}
@@ -335,6 +369,7 @@ extern int lxc_log_init(const char *name, const char *file,
 		if (strcmp(file, "none") == 0)
 			return 0;
 		ret = __lxc_log_set_file(file, 1);
+		lxc_log_use_global_fd = 1;
 	} else {
 		/* if no name was specified, there nothing to do */
 		if (!name)
@@ -385,15 +420,13 @@ extern void lxc_log_close(void)
  * happens after processing command line arguments, which override the .conf
  * settings.  So only set the level if previously unset.
  */
-extern int lxc_log_set_level(int level)
+extern int lxc_log_set_level(int *dest, int level)
 {
-	if (lxc_loglevel_specified)
-		return 0;
 	if (level < 0 || level >= LXC_LOG_PRIORITY_NOTSET) {
 		ERROR("invalid log priority %d", level);
 		return -1;
 	}
-	lxc_log_category_lxc.priority = level;
+	*dest = level;
 	return 0;
 }
 
@@ -415,11 +448,23 @@ extern bool lxc_log_has_valid_level(void)
  * happens after processing command line arguments, which override the .conf
  * settings.  So only set the file if previously unset.
  */
-extern int lxc_log_set_file(const char *fname)
+extern int lxc_log_set_file(int *fd, const char *fname)
 {
-	if (lxc_logfile_specified)
-		return 0;
-	return __lxc_log_set_file(fname, 0);
+	if (*fd != -1) {
+		close(*fd);
+		*fd = -1;
+	}
+
+	if (build_dir(fname)) {
+		ERROR("failed to create dir for log file \"%s\" : %s", fname,
+				strerror(errno));
+		return -1;
+	}
+
+	*fd = log_open(fname);
+	if (*fd == -1)
+		return -errno;
+	return 0;
 }
 
 extern const char *lxc_log_get_file(void)
@@ -440,11 +485,6 @@ extern const char *lxc_log_get_prefix(void)
 
 extern void lxc_log_options_no_override()
 {
-	if (lxc_log_get_file())
-		lxc_logfile_specified = 1;
-
-	if (lxc_log_get_level() != LXC_LOG_PRIORITY_NOTSET)
-		lxc_loglevel_specified = 1;
-
 	lxc_quiet_specified = 1;
+	lxc_loglevel_specified = 1;
 }

src/lxc/log.h

@@ -33,6 +33,8 @@
 #include <strings.h>
 #include <stdbool.h>
 
+#include "conf.h"
+
 #ifndef O_CLOEXEC
 #define O_CLOEXEC 02000000
 #endif
@@ -104,6 +106,10 @@ struct lxc_log_category {
 	const struct lxc_log_category	*parent;
 };
 
+#ifndef NO_LXC_CONF
+extern int lxc_log_use_global_fd;
+#endif
+
 /*
  * Returns true if the chained priority is equal to or higher than
  * given priority.
@@ -116,7 +122,14 @@ lxc_log_priority_is_enabled(const struct lxc_log_category* category,
 	       category->parent)
 		category = category->parent;
 
-	return priority >= category->priority;
+	int cmp_prio = category->priority;
+#ifndef NO_LXC_CONF
+	if (!lxc_log_use_global_fd && current_config &&
+			current_config->loglevel != LXC_LOG_PRIORITY_NOTSET)
+		cmp_prio = current_config->loglevel;
+#endif
+
+	return priority >= cmp_prio;
 }
 
 /*
@@ -294,18 +307,14 @@ ATTR_UNUSED static inline void LXC_##PRIORITY(struct lxc_log_locinfo* locinfo,	\
 	ERROR("%s - " format, strerror(errno), ##__VA_ARGS__);		\
 } while (0)
 
-#ifdef HAVE_TLS
-extern __thread int lxc_log_fd;
-#else
 extern int lxc_log_fd;
-#endif
 
 extern int lxc_log_init(const char *name, const char *file,
 			const char *priority, const char *prefix, int quiet,
 			const char *lxcpath);
 
-extern int lxc_log_set_file(const char *fname);
-extern int lxc_log_set_level(int level);
+extern int lxc_log_set_file(int *fd, const char *fname);
+extern int lxc_log_set_level(int *dest, int level);
 extern void lxc_log_set_prefix(const char *prefix);
 extern const char *lxc_log_get_file(void);
 extern int lxc_log_get_level(void);