tools/image-info: add support for naked partitions

In case there is no partition table, we assume the whole image is
one big partition and treat is as such.

Signed-off-by: Tom Gundersen <teg@jklm.no>

tools/image-info

@@ -59,25 +59,32 @@ def read_image_format(device):
     return qemu["format"]
 
 
+def read_partition(device, bootable, typ=None, start=0, size=0, type=None):
+   blkid = subprocess_check_output(["blkid", "--output", "export", device], parse_environment_vars)
+   return {
+       "label": blkid.get("LABEL"), # doesn't exist for mbr
+       "type": typ,
+       "uuid": blkid["UUID"],
+       "fstype": blkid["TYPE"],
+       "bootable": bootable,
+       "start": start,
+       "size": size
+   }
+
+
 def read_partition_table(device):
-    sfdisk = subprocess_check_output(["sfdisk", "--json", device], json.loads)
-    ptable = sfdisk["partitiontable"]
-    assert ptable["unit"] == "sectors"
-
     partitions = []
-    for p in ptable["partitions"]:
-        blkid = subprocess_check_output(["blkid", "--output", "export", p["node"]], parse_environment_vars)
-        partitions.append({
-            "label": blkid.get("LABEL"), # doesn't exist for mbr
-            "type": p["type"],
-            "uuid": blkid["UUID"],
-            "fstype": blkid["TYPE"],
-            "bootable": p.get("bootable", False),
-            "start": p["start"] * 512,
-            "size": p["size"] * 512
-        })
-
-    return ptable["label"], ptable["id"], partitions
+    try:
+        sfdisk = subprocess_check_output(["sfdisk", "--json", device], json.loads)
+    except subprocess.CalledProcessError:
+        partitions.append(read_partition(device, False))
+        return None, None, partitions
+    else:
+        ptable = sfdisk["partitiontable"]
+        assert ptable["unit"] == "sectors"
+        for p in ptable["partitions"]:
+            partitions.append(read_partition(p["node"], p.get("bootable", False), p["type"], p["start"] * 512, p["size"] * 512))
+        return ptable["label"], ptable["id"], partitions
 
 
 def read_bootloader_type(device):
@@ -123,38 +130,49 @@ def rpm_verify(tree):
     }
 
 
+def append_filesystem(report, tree):
+    if os.path.exists(f"{tree}/etc/os-release"):
+        report["packages"] = sorted(subprocess_check_output(["rpm", "--root", tree, "-qa"], str.split))
+        report["rpm-verify"] = rpm_verify(tree)
+
+        with open(f"{tree}/etc/os-release") as f:
+            report["os-release"] = parse_environment_vars(f.read())
+
+        try:
+            with open(f"{tree}/etc/fstab") as f:
+                report["fstab"] = sorted([line.split() for line in f.read().split("\n") if line and not line.startswith("#")])
+        except FileNotFoundError:
+            pass
+
+        with open(f"{tree}/etc/passwd") as f:
+            report["passwd"] = sorted(f.read().strip().split("\n"))
+
+        with open(f"{tree}/etc/group") as f:
+            report["groups"] = sorted(f.read().strip().split("\n"))
+
+        if os.path.exists(f"{tree}/boot") and len(os.listdir(f"{tree}/boot")) > 0:
+            assert "bootmenu" not in report
+            report["bootmenu"] = read_boot_entries(f"{tree}/boot")
+
+    elif len(glob.glob(f"{tree}/vmlinuz-*")) > 0:
+        assert "bootmenu" not in report
+        report["bootmenu"] = read_boot_entries(tree)
+
+
 report = {}
 with nbd_connect(image) as device:
     report["image-format"] = read_image_format(image)
     report["bootloader"] = read_bootloader_type(device)
     report["partition-table"], report["partition-table-id"], report["partitions"] = read_partition_table(device)
 
-    n_partitions = len(report["partitions"])
-    for n in range(1, n_partitions + 1):
-        with mount(device + f"p{n}") as tree:
-            if os.path.exists(f"{tree}/etc/os-release"):
-                report["packages"] = sorted(subprocess_check_output(["rpm", "--root", tree, "-qa"], str.split))
-                report["rpm-verify"] = rpm_verify(tree)
-
-                with open(f"{tree}/etc/os-release") as f:
-                    report["os-release"] = parse_environment_vars(f.read())
-
-                with open(f"{tree}/etc/fstab") as f:
-                    report["fstab"] = sorted([line.split() for line in f.read().split("\n") if line and not line.startswith("#")])
-
-                with open(f"{tree}/etc/passwd") as f:
-                    report["passwd"] = sorted(f.read().strip().split("\n"))
-
-                with open(f"{tree}/etc/group") as f:
-                    report["groups"] = sorted(f.read().strip().split("\n"))
-
-                if os.path.exists(f"{tree}/boot") and len(os.listdir(f"{tree}/boot")) > 0:
-                    assert "bootmenu" not in report
-                    report["bootmenu"] = read_boot_entries(f"{tree}/boot")
-
-            elif len(glob.glob(f"{tree}/vmlinuz-*")) > 0:
-                assert "bootmenu" not in report
-                report["bootmenu"] = read_boot_entries(tree)
+    if report["partition-table"]:
+        n_partitions = len(report["partitions"])
+        for n in range(1, n_partitions + 1):
+            with mount(device + f"p{n}") as tree:
+                append_filesystem(report, tree)
+    else:
+        with mount(device) as tree:
+            append_filesystem(report, tree)
 
 
 json.dump(report, sys.stdout, sort_keys=True, indent=2)