iostat: Always display persistent names with option -j

When a persistent name (e.g. UUID) is entered on the command line,
iostat displayed the real name of the device instead of its persistent
name, e.g.:

$ iostat -d -j UUID 65ccf2b5-50de-4f89-bf8e-e3e88eae4c63
Linux 5.12.14-200.fc33.x86_64 (linux-1.home) 	07/14/2021 	_x86_64_	(8 CPU)

      tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read    kB_wrtn    kB_dscd Device
     1.89         6.73         0.00     31799.48      58452         12  276250680 sda

Fix this so that the persistent name appears in the report:

$ iostat -d -j UUID 65ccf2b5-50de-4f89-bf8e-e3e88eae4c63
Linux 5.12.14-200.fc33.x86_64 (linux-1.home) 	07/14/2021 	_x86_64_	(8 CPU)

      tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read    kB_wrtn    kB_dscd Device
     1.88         6.66         0.00     31489.67      58452         12  276250680 65ccf2b5-50de-4f89-bf8e-e3e88eae4c63

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

diff --git a/iostat.c b/iostat.c
index 330f8c11f73895fa1e001c5df70814541f3a80b6..fa91464d25e0bd024ae145b9be70c05ddba3bcae 100644 (file)
--- a/iostat.c
+++ b/iostat.c
@@ -185,6 +185,47 @@ void set_devices_nonexistent(struct io_device *dlist)
        }
 }
 
+/*
+ ***************************************************************************
+ * Get device major and minor numbers.
+ *
+ * IN:
+ * @filename   Name of the device ("sda", "/dev/sdb1"...)
+ *
+ * OUT:
+ * @major      Major number of the device.
+ * @minor      Minor number of the device.
+ *
+ * RETURNS:
+ * 0 on success, and -1 otherwise.
+ ***************************************************************************
+ */
+int get_major_minor_nr(char filename[], int *major, int *minor)
+{
+       struct stat statbuf;
+       char *bang;
+       char dfile[MAX_PF_NAME];
+
+       snprintf(dfile, sizeof(dfile), "%s%s", filename[0] == '/' ? "" : SLASH_DEV, filename);
+       dfile[sizeof(dfile) - 1] = '\0';
+
+       while ((bang = strchr(dfile, '!'))) {
+               /*
+                * Some devices may have had a slash replaced with a bang character (eg. cciss!c0d0...)
+                * Restore their original names so that they can be found in /dev directory.
+                */
+               *bang = '/';
+       }
+
+       if (__stat(dfile, &statbuf) < 0)
+               return -1;
+
+       *major = __major(statbuf.st_rdev);
+       *minor = __minor(statbuf.st_rdev);
+
+       return 0;
+}
+
 /*
  ***************************************************************************
  * Check if a device is present in the list, and add it if requested.
@@ -196,6 +237,10 @@ void set_devices_nonexistent(struct io_device *dlist)
  * @dtype      T_PART_DEV (=2) if the device and all its partitions should
  *             also be read (option -p used), T_GROUP (=3) if it's a group
  *             name, and 0 otherwise.
+ * @major      Major number of the device (set to UKWN_MAJ_NR by caller if
+ *             unknown: In this case, major and minor numbers will be
+ *             determined here).
+ * @minor      Minor number of the device.
  *
  * RETURNS:
  * Pointer on the io_device structure in the list where the device is located
@@ -204,10 +249,11 @@ void set_devices_nonexistent(struct io_device *dlist)
  * don't want to add it.
  ***************************************************************************
  */
-struct io_device *add_list_device(struct io_device **dlist, char *name, int dtype)
+struct io_device *add_list_device(struct io_device **dlist, char *name, int dtype,
+                                 int major, int minor)
 {
        struct io_device *d, *ds;
-       int i, rc = 0;
+       int i, rc = 0, maj_nr, min_nr;
 
        if (strnlen(name, MAX_NAME_LEN) == MAX_NAME_LEN)
                /* Device name is too long */
@@ -277,50 +323,22 @@ struct io_device *add_list_device(struct io_device **dlist, char *name, int dtyp
                        /* This is a partition (T_PART) */
                        d->dev_tp = T_PART;
                }
-       }
-
-       return d;
-}
-
-/*
- ***************************************************************************
- * Get device major and minor numbers.
- *
- * IN:
- * @filename   Name of the device ("sda", "/dev/sdb1"...)
- *
- * OUT:
- * @major      Major number of the device.
- * @minor      Minor number of the device.
- *
- * RETURNS:
- * 0 on success, and -1 otherwise.
- ***************************************************************************
- */
-int get_major_minor_nr(char filename[], int *major, int *minor)
-{
-       struct stat statbuf;
-       char *bang;
-       char dfile[MAX_PF_NAME];
-
-       snprintf(dfile, sizeof(dfile), "%s%s", filename[0] == '/' ? "" : SLASH_DEV, filename);
-       dfile[sizeof(dfile) - 1] = '\0';
 
-       while ((bang = strchr(dfile, '!'))) {
-               /*
-                * Some devices may have had a slash replaced with a bang character (eg. cciss!c0d0...)
-                * Restore their original names so that they can be found in /dev directory.
-                */
-               *bang = '/';
+               /* Save major and minor numbers */
+               if (major != UKWN_MAJ_NR) {
+                       d->major = major;
+                       d->minor = minor;
+               }
+               else {
+                       /* Look for device major and minor numbers */
+                       if (get_major_minor_nr(d->name, &maj_nr, &min_nr) == 0) {
+                               d->major = maj_nr;
+                               d->minor = min_nr;
+                       }
+               }
        }
 
-       if (__stat(dfile, &statbuf) < 0)
-               return -1;
-
-       *major = __major(statbuf.st_rdev);
-       *minor = __minor(statbuf.st_rdev);
-
-       return 0;
+       return d;
 }
 
 /*
@@ -466,7 +484,6 @@ int read_sysfs_device_part_stat_work(int curr, char *dname, char *sysdev)
        struct io_stats sdev;
        struct io_device *d;
        char dfile[MAX_PF_NAME], filename[MAX_PF_NAME + 512];
-       int major, minor;
 
        snprintf(dfile, sizeof(dfile), "%s/%s/%s", sysdev, __BLOCK, dname);
        dfile[sizeof(dfile) - 1] = '\0';
@@ -487,17 +504,9 @@ int read_sysfs_device_part_stat_work(int curr, char *dname, char *sysdev)
                if (read_sysfs_file_stat_work(filename, &sdev) < 0)
                        continue;
 
-               d = add_list_device(&dev_list, drd->d_name, 0);
+               d = add_list_device(&dev_list, drd->d_name, 0, UKWN_MAJ_NR, 0);
                if (d != NULL) {
                        *(d->dev_stats[curr]) = sdev;
-
-                       if (!d->major) {
-                               /* Get major and minor numbers for given device */
-                               if (get_major_minor_nr(d->name, &major, &minor) == 0) {
-                                       d->major = major;
-                                       d->minor = minor;
-                               }
-                       }
                }
        }
 
@@ -557,7 +566,6 @@ int read_sysfs_all_devices_stat_work(int curr, char *sysblock)
        struct io_stats sdev;
        struct io_device *d;
        char dfile[MAX_PF_NAME];
-       int major, minor;
 
        /* Open __sys/block directory */
        if ((dir = __opendir(sysblock)) == NULL)
@@ -575,17 +583,9 @@ int read_sysfs_all_devices_stat_work(int curr, char *sysblock)
                if (read_sysfs_file_stat_work(dfile, &sdev) < 0)
                        continue;
 
-               d = add_list_device(&dev_list, drd->d_name, 0);
+               d = add_list_device(&dev_list, drd->d_name, 0, UKWN_MAJ_NR, 0);
                if (d != NULL) {
                        *(d->dev_stats[curr]) = sdev;
-
-                       if (!d->major) {
-                               /* Get major and minor numbers for given device */
-                               if (get_major_minor_nr(d->name, &major, &minor) == 0) {
-                                       d->major = major;
-                                       d->minor = minor;
-                               }
-                       }
                }
        }
 
@@ -643,15 +643,6 @@ int read_sysfs_all_devices_stat(int curr)
 int read_sysfs_part_stat_work(int curr, struct io_device *d, char *sysdev)
 {
        char dfile[MAX_PF_NAME];
-       int major, minor;
-
-       if (!d->major) {
-               /* Get major and minor numbers for given device */
-               if (get_major_minor_nr(d->name, &major, &minor) < 0)
-                       return -1;
-               d->major = major;
-               d->minor = minor;
-       }
 
        /* Read stats for device */
        snprintf(dfile, sizeof(dfile), "%s/%s/%d:%d/%s",
@@ -817,11 +808,9 @@ void read_diskstats_stat_work(int curr, char *diskstats)
                        /* Unknown entry: Ignore it */
                        continue;
 
-               d = add_list_device(&dev_list, dev_name, 0);
+               d = add_list_device(&dev_list, dev_name, 0, major, minor);
                if (d != NULL) {
                        *d->dev_stats[curr] = sdev;
-                       d->major = major;
-                       d->minor = minor;
                }
        }
        fclose(fp);
@@ -2046,7 +2035,7 @@ int main(int argc, char **argv)
                                                        }
                                                }
                                                /* Store device name */
-                                               add_list_device(&dev_list, devname, T_PART_DEV);
+                                               add_list_device(&dev_list, devname, T_PART_DEV, 0, 0);
                                        }
                                }
                                opt++;
@@ -2067,7 +2056,7 @@ int main(int argc, char **argv)
                         * and one for the trailing '\0'.
                         */
                        snprintf(group_name, MAX_NAME_LEN, " %-.*s", MAX_NAME_LEN - 2, argv[opt++]);
-                       add_list_device(&dev_list, group_name, T_GROUP);
+                       add_list_device(&dev_list, group_name, T_GROUP, 0, 0);
                }
 
                else if (!strcmp(argv[opt], "--human")) {
@@ -2256,7 +2245,7 @@ int main(int argc, char **argv)
                                                devname = persist_devname;
                                        }
                                }
-                               add_list_device(&dev_list, devname, 0);
+                               add_list_device(&dev_list, devname, 0, UKWN_MAJ_NR, 0);
                        }
                        else {
                                flags |= I_D_ALL_DEVICES;

diff --git a/iostat.h b/iostat.h
index c051db17e2fbe9cafe8071d4ef84dacfa745f5c6..261271c19ec0beb2dbee5094c00deb6b9f2b078c 100644 (file)
--- a/iostat.h
+++ b/iostat.h
@@ -60,6 +60,8 @@
 #define T_PART_DEV     2
 #define T_GROUP                3
 
+#define UKWN_MAJ_NR    0
+
 /* Environment variable */
 #define ENV_POSIXLY_CORRECT    "POSIXLY_CORRECT"
 
@@ -117,7 +119,7 @@ struct io_device {
        int dev_tp;
        /* TRUE if device exists in /proc/diskstats or /sys. Don't apply for groups. */
        int exist;
-       /* major and minor numbers are set only for partitions (T_PART), not whole devices */
+       /* major and minor numbers (not set for T_GROUP "devices") */
        int major;
        int minor;
        struct io_stats *dev_stats[2];