Degrade gracefully when squashfs-tools is missing

imageboot falls back to cp when unsquashfs is unavailable, but the build
side did not: a bare dracut_install/copy_exec aborts initramfs generation
when the binary is absent, and the capture prerequisite check refused to
capture the image at all.

Mark the initramfs copies optional and report the missing package as an
advisory rather than a hard prerequisite, so such images still build and
capture, just without the faster extraction path. Widen the EL check to
every release past el8 so future ones inherit it.

imgutil/el10/dracut/install

@@ -3,7 +3,8 @@ dracut_install /lib64/libtss2-tcti-device.so.0
 dracut_install tpm2_create tpm2_pcrread tpm2_createpolicy tpm2_createprimary
 dracut_install tpm2_load tpm2_unseal tpm2_getcap tpm2_evictcontrol
 dracut_install tpm2_pcrextend tpm2_policypcr tpm2_flushcontext tpm2_startauthsession
-dracut_install curl openssl tar cpio gzip lsmod ethtool xz unsquashfs lsmod ethtool
+dracut_install curl openssl tar cpio gzip lsmod ethtool xz lsmod ethtool
+dracut_install -o unsquashfs # optional, imageboot extracts with cp when absent
 dracut_install modprobe touch echo cut wc bash uniq grep ip hostname
 dracut_install awk egrep dirname expr sort
 dracut_install ssh sshd reboot parted mkfs mkfs.ext4 mkfs.xfs xfs_db mkswap

imgutil/el9/dracut/install

@@ -3,7 +3,8 @@ dracut_install /lib64/libtss2-tcti-device.so.0
 dracut_install tpm2_create tpm2_pcrread tpm2_createpolicy tpm2_createprimary
 dracut_install tpm2_load tpm2_unseal tpm2_getcap tpm2_evictcontrol
 dracut_install tpm2_pcrextend tpm2_policypcr tpm2_flushcontext tpm2_startauthsession
-dracut_install curl openssl tar cpio gzip lsmod ethtool xz unsquashfs lsmod ethtool
+dracut_install curl openssl tar cpio gzip lsmod ethtool xz lsmod ethtool
+dracut_install -o unsquashfs # optional, imageboot extracts with cp when absent
 dracut_install modprobe touch echo cut wc bash uniq grep ip hostname
 dracut_install awk egrep dirname expr sort
 dracut_install ssh sshd reboot parted mkfs mkfs.ext4 mkfs.xfs xfs_db mkswap

imgutil/imgutil

@@ -222,6 +222,8 @@ async def capture_remote(args):
         for cmd in unmet:
             sys.stderr.write(cmd + '\n')
         sys.exit(1)
+    for cmd in finfo.get('optionalprereqs', []):
+        sys.stderr.write(cmd + '\n')
     oscat = finfo['oscategory']
     subprocess.check_call(['ssh', '-o', 'LogLevel=QUIET', '-t', targ, 'python3', '/run/imgutil/capenv/imgutil', 'capturelocal'])
     utillib = __file__.replace('bin/imgutil', 'lib/imgutil')
@@ -471,6 +473,7 @@ class OsHandler(object):
         self.sourcepath = None
         self.osname = '{}-{}-{}'.format(name, version, arch)
         self.captureprereqs = []
+        self.captureadvisories = []
         try:
             pkglist = args.packagelist
         except AttributeError:
@@ -507,7 +510,8 @@ class OsHandler(object):
             if not isinstance(odata[idx], str):
                 odata[idx] = odata[idx].decode('utf8')
         info = {'oscategory': odata[0],
-                'version': odata[1], 'arch': odata[2], 'name': odata[3], 'unmetprereqs': self.captureprereqs}
+                'version': odata[1], 'arch': odata[2], 'name': odata[3], 'unmetprereqs': self.captureprereqs,
+                'optionalprereqs': self.captureadvisories}
         return json.dumps(info)
 
     def prep_root_premount(self, args):
@@ -681,16 +685,21 @@ class DebHandler(OsHandler):
         self.oscategory = name + version
         super().__init__(name, version, arch, args)
         needpkgs = []
+        wantpkgs = []
         if not os.path.exists(os.path.join(hostpath, 'usr/bin/tpm2_getcap')):
             needpkgs.append('tpm2-tools')
-        if not os.path.exists(os.path.join(hostpath, 'usr/bin/unsquashfs')):
-            needpkgs.append('squashfs-tools')
         lfuses = glob.glob(os.path.join(hostpath, '/lib/*/libfuse.so.2'))
         if not lfuses:
             needpkgs.append('libfuse2')
+        if not os.path.exists(os.path.join(hostpath, 'usr/bin/unsquashfs')):
+            wantpkgs.append('squashfs-tools')
         if needpkgs:
             needapt = 'Missing packages needed in target for capture, to add required packages: apt install ' + ' '.join(needpkgs)
             self.captureprereqs.append(needapt)
+        if wantpkgs:
+            wantapt = ('Missing optional packages in target, untethered boot will extract the image more slowly, '
+                       'to add them: apt install ' + ' '.join(wantpkgs))
+            self.captureadvisories.append(wantapt)
 
     def add_pkglists(self):
         self.includepkgs.extend(self.list_packages())
@@ -768,6 +777,7 @@ class ElHandler(OsHandler):
         self.yumargs = []
         super().__init__(name, version, arch, args)
         needpkgs = []
+        wantpkgs = []
         if not hostpath:
             return
         if not os.path.exists(os.path.join(hostpath, 'usr/bin/tpm2_getcap')):
@@ -781,13 +791,17 @@ class ElHandler(OsHandler):
             needpkgs.append('dhcp-client')
         if not os.path.exists(os.path.join(hostpath, 'usr/sbin/mount.nfs')):
             needpkgs.append('nfs-utils')
-        if (self.oscategory in ('el9', 'el10') and
+        if (self.oscategory not in ('el7', 'el8') and
                 not os.path.exists(os.path.join(hostpath, 'usr/sbin/unsquashfs')) and
                 not os.path.exists(os.path.join(hostpath, 'usr/bin/unsquashfs'))):
-            needpkgs.append('squashfs-tools')
+            wantpkgs.append('squashfs-tools')
         if needpkgs:
             needapt = 'Missing packages needed in target for capture, to add required packages: dnf install ' + ' '.join(needpkgs)
             self.captureprereqs.append(needapt)
+        if wantpkgs:
+            wantdnf = ('Missing optional packages in target, untethered boot will extract the image more slowly, '
+                       'to add them: dnf install ' + ' '.join(wantpkgs))
+            self.captureadvisories.append(wantdnf)
 
     def add_pkglists(self):
         self.yumargs.extend(self.list_packages())

imgutil/ubuntu/initramfs-tools/hooks/confluent

@@ -33,7 +33,7 @@ copy_exec /usr/bin/tpm2_pcrextend
 copy_exec /usr/bin/ssh-keygen
 copy_exec /usr/sbin/sshd
 copy_exec /usr/sbin/mkfs.xfs
-copy_exec /usr/bin/unsquashfs
+[ -e /usr/bin/unsquashfs ] && copy_exec /usr/bin/unsquashfs
 [ -e /usr/lib/openssh/sshd-session ] && copy_exec /usr/lib/openssh/sshd-session
 [ -e /usr/lib/x86_64-linux-gnu/libfuse.so.2 ] && copy_exec /usr/lib/x86_64-linux-gnu/libfuse.so.2
 [ -e /usr/lib/aarch64-linux-gnu/libfuse.so.2 ] && copy_exec /usr/lib/aarch64-linux-gnu/libfuse.so.2