mdadm: load default sysfs attributes after assemblation

Added new type of line to mdadm.conf which allows to specify values of
sysfs attributes for MD devices that should be loaded after the array is
assembled. Each line is interpreted as list of structures containing
sysname of MD device (md126 etc.) and list of sysfs attributes and their
values.

Signed-off-by: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Signed-off-by: Krzysztof Smolinski <krzysztof.smolinski@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

1 files changed, 158 insertions, 0 deletions

diff --git a/sysfs.c b/sysfs.c
index 2dd9ab6..c313781 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -26,9 +26,22 @@
 #include	"mdadm.h"
 #include	<dirent.h>
 #include	<ctype.h>
+#include	"dlink.h"
 
 #define MAX_SYSFS_PATH_LEN	120
 
+struct dev_sysfs_rule {
+	struct dev_sysfs_rule *next;
+	char *devname;
+	int uuid[4];
+	int uuid_set;
+	struct sysfs_entry {
+		struct sysfs_entry *next;
+		char *name;
+		char *value;
+	} *entry;
+};
+
 int load_sys(char *path, char *buf, int len)
 {
 	int fd = open(path, O_RDONLY);
@@ -999,3 +1012,148 @@ int sysfs_wait(int fd, int *msec)
 	}
 	return n;
 }
+
+int sysfs_rules_apply_check(const struct mdinfo *sra,
+			    const struct sysfs_entry *ent)
+{
+	/* Check whether parameter is regular file,
+	 * exists and is under specified directory.
+	 */
+	char fname[MAX_SYSFS_PATH_LEN];
+	char dname[MAX_SYSFS_PATH_LEN];
+	char resolved_path[PATH_MAX];
+	char resolved_dir[PATH_MAX];
+
+	if (sra == NULL || ent == NULL)
+		return -1;
+
+	snprintf(dname, MAX_SYSFS_PATH_LEN, "/sys/block/%s/md/", sra->sys_name);
+	snprintf(fname, MAX_SYSFS_PATH_LEN, "%s/%s", dname, ent->name);
+
+	if (realpath(fname, resolved_path) == NULL ||
+	    realpath(dname, resolved_dir) == NULL)
+		return -1;
+
+	if (strncmp(resolved_dir, resolved_path,
+		    strnlen(resolved_dir, PATH_MAX)) != 0)
+		return -1;
+
+	return 0;
+}
+
+static struct dev_sysfs_rule *sysfs_rules;
+
+void sysfs_rules_apply(char *devnm, struct mdinfo *dev)
+{
+	struct dev_sysfs_rule *rules = sysfs_rules;
+
+	while (rules) {
+		struct sysfs_entry *ent = rules->entry;
+		int match  = 0;
+
+		if (!rules->uuid_set) {
+			if (rules->devname)
+				match = strcmp(devnm, rules->devname) == 0;
+		} else {
+			match = memcmp(dev->uuid, rules->uuid,
+				       sizeof(int[4])) == 0;
+		}
+
+		while (match && ent) {
+			if (sysfs_rules_apply_check(dev, ent) < 0)
+				pr_err("SYSFS: failed to write '%s' to '%s'\n",
+					ent->value, ent->name);
+			else
+				sysfs_set_str(dev, NULL, ent->name, ent->value);
+			ent = ent->next;
+		}
+		rules = rules->next;
+	}
+}
+
+static void sysfs_rule_free(struct dev_sysfs_rule *rule)
+{
+	struct sysfs_entry *entry;
+
+	while (rule) {
+		struct dev_sysfs_rule *tmp = rule->next;
+
+		entry = rule->entry;
+		while (entry) {
+			struct sysfs_entry *tmp = entry->next;
+
+			free(entry->name);
+			free(entry->value);
+			free(entry);
+			entry = tmp;
+		}
+
+		if (rule->devname)
+			free(rule->devname);
+		free(rule);
+		rule = tmp;
+	}
+}
+
+void sysfsline(char *line)
+{
+	struct dev_sysfs_rule *sr;
+	char *w;
+
+	sr = xcalloc(1, sizeof(*sr));
+	for (w = dl_next(line); w != line ; w = dl_next(w)) {
+		if (strncasecmp(w, "name=", 5) == 0) {
+			char *devname = w + 5;
+
+			if (strncmp(devname, "/dev/md/", 8) == 0) {
+				if (sr->devname)
+					pr_err("Only give one device per SYSFS line: %s\n",
+						devname);
+				else
+					sr->devname = xstrdup(devname);
+			} else {
+				pr_err("%s is an invalid name for an md device - ignored.\n",
+				       devname);
+			}
+		} else if (strncasecmp(w, "uuid=", 5) == 0) {
+			char *uuid = w + 5;
+
+			if (sr->uuid_set) {
+				pr_err("Only give one uuid per SYSFS line: %s\n",
+					uuid);
+			} else {
+				if (parse_uuid(w + 5, sr->uuid) &&
+				    memcmp(sr->uuid, uuid_zero,
+					   sizeof(int[4])) != 0)
+					sr->uuid_set = 1;
+				else
+					pr_err("Invalid uuid: %s\n", uuid);
+			}
+		} else {
+			struct sysfs_entry *prop;
+
+			char *sep = strchr(w, '=');
+
+			if (sep == NULL || *(sep + 1) == 0) {
+				pr_err("Cannot parse \"%s\" - ignoring.\n", w);
+				continue;
+			}
+
+			prop = xmalloc(sizeof(*prop));
+			prop->value = xstrdup(sep + 1);
+			*sep = 0;
+			prop->name = xstrdup(w);
+			prop->next = sr->entry;
+			sr->entry = prop;
+		}
+	}
+
+	if (!sr->devname && !sr->uuid_set) {
+		pr_err("Device name not found in sysfs config entry - ignoring.\n");
+		sysfs_rule_free(sr);
+		return;
+	}
+
+	sr->next = sysfs_rules;
+	sysfs_rules = sr;
+}