lsblk: add inverse tree support (-s)

$ lsblk --inverse -o NAME /dev/dm-0
NAME
luks-10d813de-fa82-4f67-a86c-23d5d0e7c30e (dm-0)
└─sda6
  └─sda

Signed-off-by: Peter Rajnoha <prajnoha@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/lib/sysfs.c b/lib/sysfs.c
index 2340d3046df1a5a68105775956f059d90cc0d21b..a57c0a6baf57be2bc06471a2aa99430133ee6525 100644 (file)
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -281,10 +281,11 @@ int sysfs_is_partition_dirent(DIR *dir, struct dirent *d, const char *parent_nam
        char path[256];
 
 #ifdef _DIRENT_HAVE_D_TYPE
-       if (d->d_type != DT_DIR)
+       if (d->d_type != DT_DIR &&
+           d->d_type != DT_LNK)
                return 0;
 #endif
-       if (strncmp(parent_name, d->d_name, strlen(parent_name)))
+       if (parent_name && strncmp(parent_name, d->d_name, strlen(parent_name)))
                return 0;
 
        /* Cannot use /partition file, not supported on old sysfs */

diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index 52833d6747885cbe16b7607715323242a120416b..10627d3c75bf5baaeed106ad79af382570da9941 100644 (file)
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -134,6 +134,7 @@ struct lsblk {
        struct tt *tt;                  /* output table */
        unsigned int all_devices:1;     /* print all devices */
        unsigned int bytes:1;           /* print SIZE in bytes */
+       unsigned int inverse:1;         /* print inverse dependencies */
        unsigned int nodeps:1;          /* don't print slaves/holders */
 };
 
@@ -166,8 +167,9 @@ struct blkdev_cxt {
        char *uuid;             /* UUID of device / filesystem */
        char *label;            /* FS label */
 
+       int npartitions;        /* # of partitions this device has */
        int nholders;           /* # of devices mapped directly to this device
-                                * /sys/block/.../holders + number of partition */
+                                * /sys/block/.../holders */
        int nslaves;            /* # of devices this device maps to */
        int maj, min;           /* devno */
        int discard;            /* supports discard */
@@ -529,7 +531,7 @@ static void set_tt_data(struct blkdev_cxt *cxt, int col, int id, struct tt_line
                        tt_line_set_data(ln, col, xstrdup(cxt->fstype));
                break;
        case COL_TARGET:
-               if (!cxt->nholders) {
+               if (!(cxt->nholders + cxt->npartitions)) {
                        p = get_device_mountpoint(cxt);
                        if (p)
                                tt_line_set_data(ln, col, p);
@@ -551,8 +553,8 @@ static void set_tt_data(struct blkdev_cxt *cxt, int col, int id, struct tt_line
                break;
        case COL_RM:
                p = sysfs_strdup(&cxt->sysfs, "removable");
-               if (!p && cxt->parent)
-                       p = sysfs_strdup(&cxt->parent->sysfs, "removable");
+               if (!p && cxt->sysfs.parent)
+                       p = sysfs_strdup(cxt->sysfs.parent, "removable");
                if (p)
                        tt_line_set_data(ln, col, p);
                break;
@@ -685,14 +687,14 @@ static void print_device(struct blkdev_cxt *cxt, struct tt_line *tt_parent)
 
 static int set_cxt(struct blkdev_cxt *cxt,
                    struct blkdev_cxt *parent,
-                   const char *name,
-                   int partition)
+                   struct blkdev_cxt *wholedisk,
+                   const char *name)
 {
        dev_t devno;
 
        cxt->parent = parent;
        cxt->name = xstrdup(name);
-       cxt->partition = partition;
+       cxt->partition = wholedisk != NULL;
 
        cxt->filename = get_device_path(cxt);
        if (!cxt->filename) {
@@ -700,16 +702,25 @@ static int set_cxt(struct blkdev_cxt *cxt,
                return -1;
        }
 
-       devno = sysfs_devname_to_devno(name,
-                       partition && parent ? parent->name : NULL);
+       devno = sysfs_devname_to_devno(name, wholedisk ? wholedisk->name : NULL);
+
        if (!devno) {
                warnx(_("%s: unknown device name"), name);
                return -1;
        }
 
-       if (sysfs_init(&cxt->sysfs, devno, parent ? &parent->sysfs : NULL)) {
-               warnx(_("%s: failed to initialize sysfs handler"), name);
-               return -1;
+       if (lsblk->inverse) {
+               if (sysfs_init(&cxt->sysfs, devno, wholedisk ? &wholedisk->sysfs : NULL)) {
+                       warnx(_("%s: failed to initialize sysfs handler"), name);
+                       return -1;
+               }
+               if (parent)
+                       parent->sysfs.parent = &cxt->sysfs;
+       } else {
+               if (sysfs_init(&cxt->sysfs, devno, parent ? &parent->sysfs : NULL)) {
+                       warnx(_("%s: failed to initialize sysfs handler"), name);
+                       return -1;
+               }
        }
 
        cxt->maj = major(devno);
@@ -731,70 +742,157 @@ static int set_cxt(struct blkdev_cxt *cxt,
                        return -1;
                }
        }
-       cxt->nholders = sysfs_count_dirents(&cxt->sysfs, "holders") +
-                       sysfs_count_partitions(&cxt->sysfs, name);
 
+       cxt->npartitions = sysfs_count_partitions(&cxt->sysfs, name);
+       cxt->nholders = sysfs_count_dirents(&cxt->sysfs, "holders");
        cxt->nslaves = sysfs_count_dirents(&cxt->sysfs, "slaves");
 
        return 0;
 }
 
+static int process_blkdev(struct blkdev_cxt *cxt, struct blkdev_cxt *parent,
+                         int do_partitions, const char *part_name);
+
 /*
- * List devices (holders) mapped to device
+ * List device partitions if any.
  */
-static int list_holders(struct blkdev_cxt *cxt)
+static int list_partitions(struct blkdev_cxt *wholedisk_cxt, struct blkdev_cxt *parent_cxt,
+                          const char *part_name)
 {
        DIR *dir;
        struct dirent *d;
-       struct blkdev_cxt holder = {};
-
-       assert(cxt);
+       struct blkdev_cxt part_cxt = {};
+       int r = -1;
 
-       if (lsblk->nodeps)
-               return 0;
+       assert(wholedisk_cxt);
 
-       if (!cxt->nholders)
-               return 0;
+       /*
+        * Do not process further if there are no partitions for
+        * this device or the device itself is a partition.
+        */
+       if (!wholedisk_cxt->npartitions || wholedisk_cxt->partition)
+               return -1;
 
-       /* Partitions */
-       dir = sysfs_opendir(&cxt->sysfs, NULL);
+       dir = sysfs_opendir(&wholedisk_cxt->sysfs, NULL);
        if (!dir)
                err(EXIT_FAILURE, _("failed to open device directory in sysfs"));
 
        while ((d = xreaddir(dir))) {
-               if (!sysfs_is_partition_dirent(dir, d, cxt->name))
+               /* Process particular partition only? */
+               if (part_name && strcmp(part_name, d->d_name))
                        continue;
 
-               if (set_cxt(&holder, cxt, d->d_name, 1)) {
-                       reset_blkdev_cxt(&holder);
+               if (!(sysfs_is_partition_dirent(dir, d, wholedisk_cxt->name)))
                        continue;
+
+               if (lsblk->inverse) {
+                       /*
+                        * <parent_cxt>
+                        * `-<part_cxt>
+                        *   `-<wholedisk_cxt>
+                        *    `-...
+                        */
+                       if (set_cxt(&part_cxt, parent_cxt, wholedisk_cxt, d->d_name))
+                               goto next;
+
+                       if (!parent_cxt && part_cxt.nholders)
+                               goto next;
+
+                       wholedisk_cxt->parent = &part_cxt;
+                       print_device(&part_cxt, parent_cxt ? parent_cxt->tt_line : NULL);
+                       if (!lsblk->nodeps)
+                               process_blkdev(wholedisk_cxt, &part_cxt, 0, NULL);
+               } else {
+                       /*
+                        * <parent_cxt>
+                        * `-<wholedisk_cxt>
+                        *   `-<part_cxt>
+                        *    `-...
+                        */
+                       if (set_cxt(&part_cxt, wholedisk_cxt, wholedisk_cxt, d->d_name))
+                               goto next;
+                       /* Print whole disk only once */
+                       if (r)
+                               print_device(wholedisk_cxt, parent_cxt ? parent_cxt->tt_line : NULL);
+                       if (!lsblk->nodeps)
+                               process_blkdev(&part_cxt, wholedisk_cxt, 0, NULL);
                }
-               print_device(&holder, cxt->tt_line);
-               list_holders(&holder);
-               reset_blkdev_cxt(&holder);
+       next:
+               reset_blkdev_cxt(&part_cxt);
+               r = 0;
        }
+
        closedir(dir);
+       return r;
+}
+
+static int get_wholedisk_from_partition_dirent(DIR *dir, struct dirent *d,
+                                              struct blkdev_cxt *cxt)
+{
+       char path[PATH_MAX];
+       char *p;
+       int len;
+
+       if ((len = readlinkat(dirfd(dir), d->d_name, path, sizeof(path))) < 0)
+               return 0;
+       path[len]='\0';
+
+       /* The path ends with ".../<device>/<partition>" */
+       p = strrchr(path, '/'); *p = '\0';
+       p = strrchr(path, '/'); p++;
 
-       /* Holders */
-       dir = sysfs_opendir(&cxt->sysfs, "holders");
+       return set_cxt(cxt, NULL, NULL, p);
+}
+
+/*
+ * List device dependencies: partitions, holders (inverse = 0) or slaves (inverse = 1).
+ */
+static int list_deps(struct blkdev_cxt *cxt)
+{
+       DIR *dir;
+       struct dirent *d;
+       struct blkdev_cxt dep = {};
+
+       assert(cxt);
+
+       if (lsblk->nodeps)
+               return 0;
+
+       if (!(lsblk->inverse ? cxt->nslaves : cxt->nholders))
+               return 0;
+
+       dir = sysfs_opendir(&cxt->sysfs, lsblk->inverse ? "slaves" : "holders");
        if (!dir)
                return 0;
 
        while ((d = xreaddir(dir))) {
-               if (set_cxt(&holder, cxt, d->d_name, 0)) {
-                       reset_blkdev_cxt(&holder);
-                       continue;
+               /* Is the dependency a partition? */
+               if (sysfs_is_partition_dirent(dir, d, NULL)) {
+                   if (!get_wholedisk_from_partition_dirent(dir, d, &dep))
+                           process_blkdev(&dep, cxt, 1, d->d_name);
                }
-               print_device(&holder, cxt->tt_line);
-               list_holders(&holder);
-               reset_blkdev_cxt(&holder);
+               /* The dependency is a whole device. */
+               else if (!set_cxt(&dep, cxt, NULL, d->d_name))
+                       process_blkdev(&dep, cxt, 1, NULL);
+
+               reset_blkdev_cxt(&dep);
        }
        closedir(dir);
 
        return 0;
 }
 
-/* Iterate top-level devices in sysfs */
+static int process_blkdev(struct blkdev_cxt *cxt, struct blkdev_cxt *parent,
+                         int do_partitions, const char *part_name)
+{
+       if (do_partitions && cxt->npartitions)
+               return list_partitions(cxt, parent, part_name);
+
+       print_device(cxt, parent ? parent->tt_line : NULL);
+       return list_deps(cxt);
+}
+
+/* Iterate devices in sysfs */
 static int iterate_block_devices(void)
 {
        DIR *dir;
@@ -805,18 +903,17 @@ static int iterate_block_devices(void)
                return EXIT_FAILURE;
 
        while ((d = xreaddir(dir))) {
-               if (set_cxt(&cxt, NULL, d->d_name, 0))
+               if (set_cxt(&cxt, NULL, NULL, d->d_name))
                        goto next;
 
-               /* Skip devices in the middle of dependence tree */
-               if (cxt.nslaves > 0)
+               if (!lsblk->all_devices && is_maj_excluded(cxt.maj))
                        goto next;
 
-               if (!lsblk->all_devices && is_maj_excluded(cxt.maj))
+               /* Skip devices in the middle of dependency tree. */
+               if ((lsblk->inverse ? cxt.nholders : cxt.nslaves) > 0)
                        goto next;
 
-               print_device(&cxt, NULL);
-               list_holders(&cxt);
+               process_blkdev(&cxt, NULL, 1, NULL);
        next:
                reset_blkdev_cxt(&cxt);
        }
@@ -844,13 +941,14 @@ static int process_one_device(char *devname)
        }
        if (st.st_rdev == disk) {
                /*
-                * unpartitioned device
+                * Device is not a partition.
                 */
-               if (set_cxt(&cxt, NULL, buf, 0))
+               if (set_cxt(&cxt, NULL, NULL, buf))
                        goto leave;
+               process_blkdev(&cxt, NULL, !lsblk->inverse, NULL);
        } else {
                /*
-                * Parititioned, read sysfs name of the device
+                * Partition, read sysfs name of the device.
                 */
                ssize_t len;
                char path[PATH_MAX], *name;
@@ -871,14 +969,17 @@ static int process_one_device(char *devname)
                /* sysfs device name */
                name = strrchr(buf, '/') + 1;
 
-               if (set_cxt(&parent, NULL, diskname, 0))
+               if (set_cxt(&parent, NULL, NULL, diskname))
                        goto leave;
-               if (set_cxt(&cxt, &parent, name, 1))
+               if (set_cxt(&cxt, &parent, &parent, name))
                        goto leave;
+
+               if (lsblk->inverse)
+                       process_blkdev(&parent, &cxt, 1, cxt.name);
+               else
+                       process_blkdev(&cxt, &parent, 1, NULL);
        }
 
-       print_device(&cxt, NULL);
-       list_holders(&cxt);
        status = EXIT_SUCCESS;
 leave:
        free(diskname);
@@ -938,6 +1039,7 @@ static void __attribute__((__noreturn__)) help(FILE *out)
                " -o, --output <list>  output columns\n"
                " -P, --pairs          use key=\"value\" output format\n"
                " -r, --raw            use raw output format\n"
+               " -s, --inverse        inverse dependencies\n"
                " -t, --topology       output info about topology\n"));
 
        fprintf(out, _("\nAvailable columns:\n"));
@@ -981,6 +1083,7 @@ int main(int argc, char *argv[])
                { "list",       0, 0, 'l' },
                { "ascii",      0, 0, 'i' },
                { "raw",        0, 0, 'r' },
+               { "inverse",    0, 0, 's' },
                { "fs",         0, 0, 'f' },
                { "exclude",    1, 0, 'e' },
                { "topology",   0, 0, 't' },
@@ -995,7 +1098,7 @@ int main(int argc, char *argv[])
        lsblk = &_ls;
        memset(lsblk, 0, sizeof(*lsblk));
 
-       while((c = getopt_long(argc, argv, "abdDe:fhlnmo:Pirt", longopts, NULL)) != -1) {
+       while((c = getopt_long(argc, argv, "abdDe:fhlnmo:Pirst", longopts, NULL)) != -1) {
                switch(c) {
                case 'a':
                        lsblk->all_devices = 1;
@@ -1046,6 +1149,9 @@ int main(int argc, char *argv[])
                        tt_flags &= ~TT_FL_TREE;        /* disable the default */
                        tt_flags |= TT_FL_RAW;          /* enable raw */
                        break;
+               case 's':
+                       lsblk->inverse = 1;
+                       break;
                case 'f':
                        columns[ncolumns++] = COL_NAME;
                        columns[ncolumns++] = COL_FSTYPE;