[Libguestfs] [PATCH 6/6] New API: btrfs_subvolume_show

[Hu Tao]

btrfs_subvolume_show shows the detailed information of a subvolume or
snapshot.

Signed-off-by: Hu Tao <hutao at cn.fujitsu.com>
---
 daemon/btrfs.c       | 167 +++++++++++++++++++++++++++++++++++++++++++++++++++
 generator/actions.ml |   9 +++
 src/MAX_PROC_NR      |   2 +-
 3 files changed, 177 insertions(+), 1 deletion(-)

diff --git a/daemon/btrfs.c b/daemon/btrfs.c
index e179b57..36ba588 100644
--- a/daemon/btrfs.c
+++ b/daemon/btrfs.c
@@ -29,6 +29,7 @@
 #include "actions.h"
 #include "optgroups.h"
 #include "xstrtol.h"
+#include "c-ctype.h"
 
 GUESTFSD_EXT_CMD(str_btrfs, btrfs);
 GUESTFSD_EXT_CMD(str_btrfstune, btrfstune);
@@ -813,3 +814,169 @@ do_btrfs_fsck (const char *device, int64_t superblock, int repair)
 
   return 0;
 }
+
+char **do_btrfs_subvolume_show (const char *subvolume)
+{
+  const size_t MAX_ARGS = 64;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  CLEANUP_FREE char *subvolume_buf = NULL;
+  CLEANUP_FREE char *err = NULL;
+  CLEANUP_FREE char *out = NULL;
+  char *p, *pend, *colon;
+  DECLARE_STRINGSBUF (ret);
+  int r;
+
+  subvolume_buf = sysroot_path (subvolume);
+  if (subvolume_buf == NULL) {
+    reply_with_perror ("malloc");
+    return NULL;
+  }
+
+  ADD_ARG (argv, i, str_btrfs);
+  ADD_ARG (argv, i, "subvolume");
+  ADD_ARG (argv, i, "show");
+  ADD_ARG (argv, i, subvolume_buf);
+  ADD_ARG (argv, i, NULL);
+
+  r = commandv (&out, &err, argv);
+  if (r == -1) {
+    reply_with_error ("%s: %s", subvolume, err);
+    return NULL;
+  }
+
+  /* Output is:
+   *
+   * /
+   *         Name:                   root
+   *         uuid:                   c875169e-cf4e-a04d-9959-b667dec36234
+   *         Parent uuid:            -
+   *         Creation time:          2014-11-13 10:13:08
+   *         Object ID:              256
+   *         Generation (Gen):       6579
+   *         Gen at creation:        5
+   *         Parent:                 5
+   *         Top Level:              5
+   *         Flags:                  -
+   *         Snapshot(s):
+   *                                 snapshots/test1
+   *                                 snapshots/test2
+   *                                 snapshots/test3
+   *
+   */
+
+  p = out;
+
+  p = strchr (p, '\n');
+  if (p) {
+    *p = '\0';
+    p++;
+  }
+  else {
+    reply_with_error ("truncated output");
+    return NULL;
+  }
+
+  /* If the path is the btrfs root, `btrfs subvolume show' reports:
+   *   <path> is btrfs root
+   */
+  if (strstr(out, "is btrfs root") != NULL) {
+    reply_with_error ("%s is btrfs root", subvolume);
+    return NULL;
+  }
+
+  /* The first line is the path of the subvolume. */
+  if (add_string (&ret, strdup("path")) == -1) {
+    return NULL;
+  }
+  if (add_string (&ret, out) == -1) {
+    return NULL;
+  }
+
+  /* Read the lines and split into "key: value". */
+  while (*p) {
+    /* leading spaces and tabs */
+    while (*p && c_isspace (*p)) p++;
+
+    pend = strchrnul (p, '\n');
+    if (*pend == '\n') {
+      *pend = '\0';
+      pend++;
+    }
+
+    if (!*p) continue;
+
+    colon = strchr (p, ':');
+    if (colon) {
+      *colon = '\0';
+
+      /* snapshot is special, see the output above */
+      if (strncmp(p, "Snapshot", sizeof("Snapshot") - 1) == 0) {
+        char *ss = NULL;
+
+        if (add_string (&ret, p) == -1) {
+          return NULL;
+        }
+
+        /* each line is the path of a snapshot. */
+        p = pend;
+        while (*p && strchr(p, ':') == NULL) {
+          while (*p && c_isspace (*p)) p++;
+          pend = strchrnul (p, '\n');
+          if (*pend == '\n') {
+            *pend = '\0';
+            pend++;
+          }
+          if (ss) {
+            ss = realloc(ss, strlen(ss) + strlen(p));
+            strcat(ss, ",");
+            strcat(ss, p);
+          } else {
+            ss = strdup(p);
+          }
+
+          p = pend;
+        }
+
+        if (ss) {
+          if (add_string (&ret, ss) == -1) {
+            free(ss);
+            return NULL;
+          }
+        }
+        else {
+          if (add_string (&ret, strdup("")) == -1) {
+            return NULL;
+          }
+        }
+
+        continue;
+      }
+
+      do { colon++; } while (*colon && c_isspace (*colon));
+
+      if (add_string (&ret, p) == -1) {
+        return NULL;
+      }
+      if (add_string (&ret, colon) == -1) {
+        return NULL;
+      }
+    }
+    else {
+      if (add_string (&ret, p) == -1) {
+        return NULL;
+      }
+      if (add_string (&ret, "") == -1) {
+        return NULL;
+      }
+    }
+
+    p = pend;
+  }
+
+  if (end_stringsbuf (&ret) == -1)
+    return NULL;
+
+  return ret.argv;
+
+}
diff --git a/generator/actions.ml b/generator/actions.ml
index cf96039..24d3ecc 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -12014,6 +12014,15 @@ This is the internal call which implements C<guestfs_lstatnslist>." };
     longdesc = "\
 Get the default subvolume or snapshot of a filesystem mounted at C<mountpoint>." };
 
+  { defaults with
+    name = "btrfs_subvolume_show";
+    style = RHashtable "btrfssubvolumeinfo", [Pathname "subvolume"], [];
+    proc_nr = Some 425;
+    optional = Some "btrfs"; camel_name = "BTRFSSubvolumeShow";
+    shortdesc = "show detailed information of the subvolume";
+    longdesc = "\
+show detailed information of the subvolume." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 9524ef4..5e4a522 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-424
+425
-- 
1.9.3