Make device name consistent between sar and iostat

Use a common function to determine the name of the device to be
displayed by sar (sar -d) and iostat.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>

common.c

@@ -36,6 +36,7 @@
 
 #include "version.h"
 #include "common.h"
+#include "ioconf.h"
 
 #ifdef USE_NLS
 #include <locale.h>
@@ -1048,6 +1049,154 @@ char *get_pretty_name_from_persistent(char *persistent)
 	return pretty;
 }
 
+/*
+ * **************************************************************************
+ * Try to get device real name from sysfs tree.
+ *
+ * IN:
+ * @major	Major number of the device.
+ * @minor	Minor number of the device.
+ *
+ * RETURNS:
+ * The name of the device, which may be the real name (as it appears in /dev)
+ * or NULL.
+ ***************************************************************************
+ */
+char *get_devname_from_sysfs(unsigned int major, unsigned int minor)
+{
+	static char link[256], target[PATH_MAX];
+	char *devname;
+	ssize_t r;
+
+	snprintf(link, 256, "%s/%u:%u", SYSFS_DEV_BLOCK, major, minor);
+
+	/* Get full path to device knowing its major and minor numbers */
+	r = readlink(link, target, PATH_MAX);
+	if (r <= 0 || r >= PATH_MAX) {
+		return (NULL);
+	}
+
+	target[r] = '\0';
+
+	/* Get device name */
+	devname = basename(target);
+	if (!devname || strnlen(devname, FILENAME_MAX) == 0) {
+		return (NULL);
+	}
+
+	return (devname);
+}
+
+/*
+ * **************************************************************************
+ * Get device real name if possible.
+ *
+ * IN:
+ * @major	Major number of the device.
+ * @minor	Minor number of the device.
+ *
+ * RETURNS:
+ * The name of the device, which may be the real name (as it appears in /dev)
+ * or a string with the following format devM-n.
+ ***************************************************************************
+ */
+char *get_devname(unsigned int major, unsigned int minor)
+{
+	static char buf[32];
+	char *name;
+
+	name = get_devname_from_sysfs(major, minor);
+	if (name != NULL)
+		return (name);
+
+	name = ioc_name(major, minor);
+	if ((name != NULL) && strcmp(name, K_NODEV))
+		return (name);
+
+	snprintf(buf, 32, "dev%u-%u", major, minor);
+	return (buf);
+}
+
+/*
+ * **************************************************************************
+ * Get device name (whether pretty-printed, persistent or not).
+ *
+ * IN:
+ * @major		Major number of the device.
+ * @minor		Minor number of the device.
+ * @wwn			WWN identifier of the device (0 if unknown).
+ * @part_nr		Partition number (0 if unknown).
+ * @disp_devmap_name	Display device mapper name.
+ * @disp_persist_name	Display persistent name of the device.
+ * @use_stable_id	Display stable-across-reboots name.
+ * @dflt_name		Device name to use by default (if existent).
+ *
+ * RETURNS:
+ * The name of the device.
+ ***************************************************************************
+ */
+char *get_device_name(unsigned int major, unsigned int minor, unsigned long long wwn[],
+		      unsigned int part_nr, unsigned int disp_devmap_name,
+		      unsigned int disp_persist_name, unsigned int use_stable_id,
+		      char *dflt_name)
+{
+	static unsigned int dm_major = 0;
+	char *dev_name = NULL, *persist_dev_name = NULL, *bang;
+	static char sid[64], dname[MAX_NAME_LEN];
+	char xsid[32] = "", pn[16] = "";
+
+	if (disp_persist_name) {
+		persist_dev_name = get_persistent_name_from_pretty(get_devname(major, minor));
+	}
+
+	if (persist_dev_name) {
+		dev_name = persist_dev_name;
+	}
+	else {
+		if (use_stable_id && (wwn[0] != 0)) {
+			if (wwn[1] != 0) {
+				sprintf(xsid, "%016llx", wwn[1]);
+			}
+			if (part_nr) {
+				sprintf(pn, "-%d", part_nr);
+			}
+			snprintf(sid, sizeof(sid), "%#016llx%s%s", wwn[0], xsid, pn);
+			dev_name = sid;
+		}
+		else if (disp_devmap_name) {
+			if (!dm_major) {
+				dm_major = get_devmap_major();
+			}
+			if (major == dm_major) {
+				dev_name = transform_devmapname(major, minor);
+			}
+		}
+
+		if (!dev_name) {
+			if (dflt_name) {
+				dev_name = dflt_name;
+			}
+			else {
+				dev_name = get_devname(major, minor);
+			}
+		}
+	}
+
+	strncpy(dname, dev_name, sizeof(dname));
+	dname[sizeof(dname) - 1] = '\0';
+
+	while ((bang = strchr(dname, '!'))) {
+		/*
+		 * Some devices may have had a slash replaced with
+		 * a bang character (eg. cciss!c0d0...)
+		 * Restore their original names.
+		 */
+		*bang = '/';
+	}
+
+	return dname;
+}
+
 /*
  ***************************************************************************
  * Init color strings.

common.h

@@ -273,6 +273,9 @@ void cprintf_x
 	(int, int, ...);
 char *device_name
 	(char *);
+char *get_device_name
+	(unsigned int, unsigned int, unsigned long long [],
+	 unsigned int, unsigned int, unsigned int, unsigned int, char *);
 unsigned int get_devmap_major
 	(void);
 unsigned long long get_interval

iostat.c

@@ -67,7 +67,6 @@ int dplaces_nr = -1;
 int group_nr = 0;	/* Nb of device groups */
 int cpu_nr = 0;		/* Nb of processors on the machine */
 int flags = 0;		/* Flag for common options and system state */
-unsigned int dm_major;	/* Device-mapper major number */
 
 long interval = 0;
 char timestamp[TIMESTAMP_LEN];
@@ -1709,7 +1708,7 @@ void write_stats(int curr, struct tm *rectime, int skip)
 	int h, hl = 0, hh = 0, fctr = 1, tab = 4, next = FALSE;
 	unsigned long long itv;
 	struct io_device *d, *dtmp, *g = NULL, *dnext = NULL;
-	char *dev_name, *pdname, *bang, dname[MAX_NAME_LEN];
+	char *dev_name, *pdname;
 
 	/* Test stdout */
 	TEST_STDOUT(STDOUT_FILENO);
@@ -1835,39 +1834,10 @@ void write_stats(int curr, struct tm *rectime, int skip)
 					    ioj = &iozero;
 				}
 
-				/* Get device name to print */
-				dev_name = NULL;
-
-				if ((DISPLAY_DEVMAP_NAME(flags)) && (d->major == dm_major)) {
-					/*
-					 * If the device is a device mapper device, try to get its
-					 * assigned name of its logical device.
-					 */
-					 dev_name = transform_devmapname(d->major, d->minor);
-				}
-
-				if (DISPLAY_PERSIST_NAME_I(flags)) {
-					pdname = get_persistent_name_from_pretty(dev_name ? dev_name : d->name);
-					if (pdname) {
-						dev_name = pdname;
-					}
-				}
-
-				if (!dev_name) {
-					dev_name = d->name;
-				}
-				strncpy(dname, dev_name, sizeof(dname));
-				dname[sizeof(dname) - 1] = '\0';
-
-				while ((bang = strchr(dname, '!'))) {
-					/*
-					 * Some devices may have had a slash replaced with
-					 * a bang character (eg. cciss!c0d0...)
-					 * Restore their original names.
-					 */
-					*bang = '/';
-				}
-
+				dev_name = get_device_name(d->major, d->minor, NULL, 0,
+							   DISPLAY_DEVMAP_NAME(flags),
+							   DISPLAY_PERSIST_NAME_I(flags),
+							   FALSE, d->name);
 #ifdef DEBUG
 				if (DISPLAY_DEBUG(flags)) {
 					/* Debug output */
@@ -1880,7 +1850,7 @@ void write_stats(int curr, struct tm *rectime, int skip)
 						"fl_ios=%lu fl_ticks=%u "
 						"ios_pgr=%u tot_ticks=%u "
 						"rq_ticks=%u }\n",
-						dname,
+						dev_name,
 						itv,
 						fctr,
 						ioi->rd_sectors,
@@ -1910,10 +1880,10 @@ void write_stats(int curr, struct tm *rectime, int skip)
 					next = TRUE;
 
 					if (DISPLAY_EXTENDED(flags)) {
-						write_ext_stat(itv, fctr, h, d, ioi, ioj, tab, dname);
+						write_ext_stat(itv, fctr, h, d, ioi, ioj, tab, dev_name);
 					}
 					else {
-						write_basic_stat(itv, fctr, d, ioi, ioj, tab, dname);
+						write_basic_stat(itv, fctr, d, ioi, ioj, tab, dev_name);
 					}
 				}
 			}
@@ -2349,10 +2319,6 @@ int main(int argc, char **argv)
 	/* Select disk output unit (kB/s or blocks/s) */
 	set_disk_output_unit();
 
-	if (DISPLAY_DEVMAP_NAME(flags)) {
-		dm_major = get_devmap_major();
-	}
-
 	if (DISPLAY_JSON_OUTPUT(flags)) {
 		/* Use a decimal point to make JSON code compliant with RFC7159 */
 		setlocale(LC_NUMERIC, "C");

json_stats.c

@@ -762,8 +762,9 @@ __print_funct_t json_print_disk_stats(struct activity *a, int curr, int tab,
 		}
 
 		/* Get device name */
-		dev_name = get_sa_devname(sdc->major, sdc->minor,
-					  sdc->wwn, sdc->part_nr, flags);
+		dev_name = get_device_name(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr,
+					   DISPLAY_PRETTY(flags), DISPLAY_PERSIST_NAME_S(flags),
+					   USE_STABLE_ID(flags), NULL);
 
 		if (a->item_list != NULL) {
 			/* A list of devices has been entered on the command line */

pcp_stats.c

@@ -610,8 +610,9 @@ __print_funct_t pcp_print_disk_stats(struct activity *a, int curr, unsigned long
 		}
 
 		/* Get device name */
-		dev_name = get_sa_devname(sdc->major, sdc->minor,
-					  sdc->wwn, sdc->part_nr, flags);
+		dev_name = get_device_name(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr,
+					   DISPLAY_PRETTY(flags), DISPLAY_PERSIST_NAME_S(flags),
+					   USE_STABLE_ID(flags), NULL);
 
 		if (a->item_list != NULL) {
 			/* A list of devices has been entered on the command line */

pr_stats.c

@@ -1049,7 +1049,9 @@ __print_funct_t print_disk_stats(struct activity *a, int prev, int curr,
 			continue;
 
 		/* Get device name */
-		dev_name = get_sa_devname(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr, flags);
+		dev_name = get_device_name(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr,
+					   DISPLAY_PRETTY(flags), DISPLAY_PERSIST_NAME_S(flags),
+					   USE_STABLE_ID(flags), NULL);
 
 		if (a->item_list != NULL) {
 			/* A list of devices has been entered on the command line */

raw_stats.c

@@ -537,8 +537,9 @@ __print_funct_t raw_print_disk_stats(struct activity *a, char *timestr, int curr
 		sdc = (struct stats_disk *) ((char *) a->buf[curr] + i * a->msize);
 
 		/* Get device name */
-		dev_name = get_sa_devname(sdc->major, sdc->minor,
-					  sdc->wwn, sdc->part_nr, flags);
+		dev_name = get_device_name(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr,
+					   DISPLAY_PRETTY(flags), DISPLAY_PERSIST_NAME_S(flags),
+					   USE_STABLE_ID(flags), NULL);
 
 		if (a->item_list != NULL) {
 			/* A list of devices has been entered on the command line */

rndr_stats.c

@@ -1091,8 +1091,9 @@ __print_funct_t render_disk_stats(struct activity *a, int isdb, char *pre,
 		}
 
 		/* Get device name */
-		dev_name = get_sa_devname(sdc->major, sdc->minor,
-					  sdc->wwn, sdc->part_nr, flags);
+		dev_name = get_device_name(sdc->major, sdc->minor, sdc->wwn, sdc->part_nr,
+					   DISPLAY_PRETTY(flags), DISPLAY_PERSIST_NAME_S(flags),
+					   USE_STABLE_ID(flags), NULL);
 
 		if (a->item_list != NULL) {
 			/* A list of devices has been entered on the command line */