use a default per-container logfile

configure.ac

@@ -157,6 +157,26 @@ AC_ARG_WITH([rootfs-path],
 		[lxc rootfs mount point]
 	)], [], [with_rootfs_path=['${libdir}/lxc/rootfs']])
 
+# Container log path.  By default, use $lxcpath.
+AC_MSG_CHECKING([Whether to place logfiles in container config path])
+AC_ARG_ENABLE([configpath-log],
+	[AC_HELP_STRING([--enable-configpath-log], [use logfiles in config path])],
+	[use_configpath_logs=yes], [use_configpath_logs=no])
+AC_MSG_RESULT([$use_configpath_logs])
+AM_CONDITIONAL([USE_CONFIGPATH_LOGS], [test "$use_configpath_logs" = "yes"])
+
+if test "$use_configpath_logs" = "yes"; then
+	default_log_path="${with_config_path}"
+else
+	default_log_path="/var/log/lxc"
+fi
+
+AC_ARG_WITH([log-path],
+	[AC_HELP_STRING(
+		[--with-log-path=dir],
+		[per container log path]
+	)], [], [with_log_path=['${default_log_path}']])
+
 # Expand some useful variables
 AS_AC_EXPAND(PREFIX, "$prefix")
 AS_AC_EXPAND(LIBDIR, "$libdir")
@@ -173,6 +193,7 @@ AS_AC_EXPAND(LXCPATH, "$with_config_path")
 AS_AC_EXPAND(LXCROOTFSMOUNT, "$with_rootfs_path")
 AS_AC_EXPAND(LXCTEMPLATEDIR, "$datadir/lxc/templates")
 AS_AC_EXPAND(LXCINITDIR, "$libexecdir")
+AS_AC_EXPAND(LOGPATH, "$with_log_path")
 
 # Check for some standard kernel headers
 AC_CHECK_HEADERS([linux/unistd.h linux/netlink.h linux/genetlink.h],

src/lxc/Makefile.am

@@ -89,12 +89,17 @@ AM_CFLAGS=-I$(top_srcdir)/src \
 	-DLXCROOTFSMOUNT=\"$(LXCROOTFSMOUNT)\" \
 	-DLXCPATH=\"$(LXCPATH)\" \
 	-DLXCINITDIR=\"$(LXCINITDIR)\" \
-	-DLXCTEMPLATEDIR=\"$(LXCTEMPLATEDIR)\"
+	-DLXCTEMPLATEDIR=\"$(LXCTEMPLATEDIR)\" \
+	-DLOGPATH=\"$(LOGPATH)\"
 
 if ENABLE_APPARMOR
 AM_CFLAGS += -DHAVE_APPARMOR
 endif
 
+if USE_CONFIGPATH_LOGS
+AM_CFLAGS += -DUSE_CONFIGPATH_LOGS
+endif
+
 if ENABLE_SECCOMP
 AM_CFLAGS += -DHAVE_SECCOMP
 liblxc_so_SOURCES += seccomp.c

src/lxc/confile.c

@@ -927,11 +927,6 @@ static int config_aa_profile(const char *key, const char *value,
 static int config_logfile(const char *key, const char *value,
 			     struct lxc_conf *lxc_conf)
 {
-	if (lxc_log_get_file()) {
-		DEBUG("Log file already specified - ignoring new value");
-		return 0;
-	}
-
 	return lxc_log_set_file(value);
 }
 

src/lxc/log.c

@@ -42,6 +42,8 @@
 int lxc_log_fd = -1;
 static char log_prefix[LXC_LOG_PREFIX_SIZE] = "lxc";
 static int lxc_loglevel_specified = 0;
+// if logfile was specifed on command line, it won't be overridden by lxc.logfile
+static int lxc_log_specified = 0;
 
 lxc_log_define(lxc_log, lxc);
 
@@ -123,6 +125,36 @@ extern void lxc_log_setprefix(const char *prefix)
 	log_prefix[sizeof(log_prefix) - 1] = 0;
 }
 
+static int build_dir(const char *name)
+{
+	char *n = strdup(name);  // because we'll be modifying it
+	char *p, *e;
+	int ret;
+
+	if (!n) {
+		ERROR("Out of memory while creating directory '%s'.", name);
+		return -1;
+	}
+
+	e = &n[strlen(n)];
+	for (p = n+1; p < e; p++) {
+		if (*p != '/')
+			continue;
+		*p = '\0';
+		if (access(n, F_OK)) {
+			ret = lxc_unpriv(mkdir(n, 0755));
+			if (ret && errno != -EEXIST) {
+				SYSERROR("failed to create directory '%s'.", n);
+				free(n);
+				return -1;
+			}
+		}
+		*p = '/';
+	}
+	free(n);
+	return 0;
+}
+
 /*---------------------------------------------------------------------------*/
 static int log_open(const char *name)
 {
@@ -148,11 +180,46 @@ static int log_open(const char *name)
 	return newfd;
 }
 
+static char *build_log_path(const char *name)
+{
+	char *p;
+	int len, ret;
+
+	/*
+	 * '$logpath' + '/' + '$name' + '.log' + '\0'
+	 * or
+	 * '$logpath' + '/' + '$name' + '/' + '$name' + '.log' + '\0'
+	 * sizeof(LOGPATH) includes its \0
+	 */
+	len = sizeof(LOGPATH) + strlen(name) + 6;
+#if USE_CONFIGPATH_LOGS
+	len += strlen(name) + 1;  /* add "/$container_name/" */
+#endif
+	p = malloc(len);
+	if (!p)
+		return p;
+#if USE_CONFIGPATH_LOGS
+	ret = snprintf(p, len, "%s/%s/%s.log", LOGPATH, name, name);
+#else
+	ret = snprintf(p, len, "%s/%s.log", LOGPATH, name);
+#endif
+	if (ret < 0 || ret >= len) {
+		free(p);
+		return NULL;
+	}
+	return p;
+}
+
+int do_lxc_log_set_file(const char *fname, int from_default);
+
 /*---------------------------------------------------------------------------*/
-extern int lxc_log_init(const char *file, const char *priority,
-			const char *prefix, int quiet)
+extern int lxc_log_init(const char *name, const char *file,
+			const char *priority, const char *prefix, int quiet)
 {
 	int lxc_priority = LXC_LOG_PRIORITY_ERROR;
+	int ret;
+	char *tmpfile = NULL;
+	int want_lxc_log_specified = 0;
 
 	if (lxc_log_fd != -1)
 		return 0;
@@ -176,10 +243,38 @@ extern int lxc_log_init(const char *file, const char *priority,
 	if (prefix)
 		lxc_log_setprefix(prefix);
 
-	if (file)
-		return lxc_log_set_file(file);
+	if (file && strcmp(file, "none") == 0) {
+		want_lxc_log_specified = 1;
+		return 0;
+	}
 
-	return 0;
+	if (!file) {
+		tmpfile = build_log_path(name);
+		if (!tmpfile) {
+			ERROR("could not build log path");
+			return -1;
+		}
+	} else {
+		want_lxc_log_specified = 1;
+	}
+
+	ret = do_lxc_log_set_file(tmpfile ? tmpfile : file, !want_lxc_log_specified);
+
+	if (want_lxc_log_specified)
+		lxc_log_specified = 1;
+	/*
+	 * If !want_lxc_log_specified, that is, if the user did not request
+	 * this logpath, then ignore failures and continue logging to console
+	 */
+	if (!want_lxc_log_specified && ret != 0) {
+		INFO("Ignoring failure to open default logfile.");
+		ret = 0;
+	}
+
+	if (tmpfile)
+		free(tmpfile);
+
+	return ret;
 }
 
 /*
@@ -200,30 +295,50 @@ extern int lxc_log_set_level(int level)
 }
 
 char *log_fname;  // default to NULL, set in lxc_log_set_file.
-
 /*
- * This is called when we read a lxc.logfile entry in a lxc.conf file.  This
- * happens after processing command line arguments, which override the .conf
- * settings.  So only set the logfile if previously unset.
+ * This can be called:
+ *   1. when a program calls lxc_log_init with no logfile parameter (in which
+ *      case the default is used).  In this case lxc.logfile can override this.
+ *   2. when a program calls lxc_log_init with a logfile parameter.  In this
+ *	case we don't want lxc.logfile to override this.
+ *   3. When a lxc.logfile entry is found in config file.
  */
-extern int lxc_log_set_file(const char *fname)
+int do_lxc_log_set_file(const char *fname, int from_default)
 {
+	if (lxc_log_specified) {
+		INFO("lxc.logfile overriden by command line");
+		return 0;
+	}
 	if (lxc_log_fd != -1) {
-		// this should've been caught at config_logfile.
-		ERROR("Race in setting logfile?");
+		// we are overriding the default.
+		close(lxc_log_fd);
+		free(log_fname);
+	}
+
+#if USE_CONFIGPATH_LOGS
+	// we don't build_dir for the default if the default is
+	// i.e. /var/lib/lxc/$container/$container.log
+	if (!from_default)
+#endif
+	if (build_dir(fname)) {
+		ERROR("failed to create dir for log file \"%s\" : %s", fname,
+		      strerror(errno));
 		return -1;
 	}
 
 	lxc_log_fd = log_open(fname);
-	if (lxc_log_fd == -1) {
-		ERROR("failed to open log file %s\n", fname);
+	if (lxc_log_fd == -1)
 		return -1;
-	}
 
 	log_fname = strdup(fname);
 	return 0;
 }
 
+extern int lxc_log_set_file(const char *fname)
+{
+	return do_lxc_log_set_file(fname, 0);
+}
+
 extern int lxc_log_get_level(void)
 {
 	if (!lxc_loglevel_specified)

src/lxc/log.h

@@ -287,8 +287,8 @@ extern struct lxc_log_category lxc_log_category_lxc;
 
 extern int lxc_log_fd;
 
-extern int lxc_log_init(const char *file, const char *priority,
-			const char *prefix, int quiet);
+extern int lxc_log_init(const char *name, const char *file,
+			const char *priority, const char *prefix, int quiet);
 
 extern void lxc_log_setprefix(const char *a_prefix);
 extern int lxc_log_set_level(int level);

src/lxc/lxc_attach.c

@@ -139,7 +139,7 @@ int main(int argc, char *argv[])
 	if (ret)
 		return ret;
 
-	ret = lxc_log_init(my_args.log_file, my_args.log_priority,
+	ret = lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			   my_args.progname, my_args.quiet);
 	if (ret)
 		return ret;

src/lxc/lxc_cgroup.c

@@ -68,7 +68,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_checkpoint.c

@@ -115,7 +115,7 @@ int main(int argc, char *argv[])
 	if (ret)
 		return ret;
 
-	ret = lxc_log_init(my_args.log_file, my_args.log_priority,
+	ret = lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			   my_args.progname, my_args.quiet);
 	if (ret)
 		return ret;

src/lxc/lxc_console.c

@@ -187,7 +187,7 @@ int main(int argc, char *argv[])
 	if (err)
 		return -1;
 
-	err = lxc_log_init(my_args.log_file, my_args.log_priority,
+	err = lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			   my_args.progname, my_args.quiet);
 	if (err)
 		return -1;

src/lxc/lxc_execute.c

@@ -99,7 +99,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_freeze.c

@@ -54,7 +54,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_info.c

@@ -79,7 +79,7 @@ int main(int argc, char *argv[])
 	if (ret)
 		return 1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return 1;
 

src/lxc/lxc_init.c

@@ -79,7 +79,7 @@ int main(int argc, char *argv[])
 	if (lxc_caps_init())
 		exit(err);
 
-	if (lxc_log_init(NULL, 0, basename(argv[0]), quiet))
+	if (lxc_log_init(NULL, "none", 0, basename(argv[0]), quiet))
 		exit(err);
 
 	if (!argv[optind]) {

src/lxc/lxc_kill.c

@@ -61,7 +61,7 @@ int main(int argc, char *argv[], char *envp[])
 	if (ret)
 		return ret;
 
-	ret = lxc_log_init(my_args.log_file, my_args.log_priority,
+	ret = lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			   my_args.progname, my_args.quiet);
 	if (ret)
 		return ret;

src/lxc/lxc_monitor.c

@@ -65,7 +65,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_restart.c

@@ -122,7 +122,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_start.c

@@ -164,7 +164,7 @@ int main(int argc, char *argv[])
 	else
 		args = my_args.argv;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return err;
 

src/lxc/lxc_stop.c

@@ -53,7 +53,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_unfreeze.c

@@ -53,7 +53,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxc_wait.c

@@ -83,7 +83,7 @@ int main(int argc, char *argv[])
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
-	if (lxc_log_init(my_args.log_file, my_args.log_priority,
+	if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 			 my_args.progname, my_args.quiet))
 		return -1;
 

src/lxc/lxccontainer.c

@@ -976,7 +976,7 @@ struct lxc_container *lxc_container_new(const char *name)
 	c->set_cgroup_item = lxcapi_set_cgroup_item;
 
 	/* we'll allow the caller to update these later */
-	if (lxc_log_init(NULL, NULL, "lxc_container", 0)) {
+	if (lxc_log_init(NULL, "none", NULL, "lxc_container", 0)) {
 		fprintf(stderr, "failed to open log\n");
 		goto err;
 	}