[PATCH] qemu-shim: add a --with-config option

[marcandre.lureau at redhat.com]

From: Marc-André Lureau <marcandre.lureau at redhat.com>

Add an option to ease setting up a VM with existing libvirt qemu.conf.

Fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=1817776

Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
---
 docs/manpages/virt-qemu-run.rst |  6 ++++++
 src/libvirt_private.syms        |  1 -
 src/qemu/qemu_shim.c            | 36 +++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/docs/manpages/virt-qemu-run.rst b/docs/manpages/virt-qemu-run.rst
index b06c311b1d..3196b4c8f4 100644
--- a/docs/manpages/virt-qemu-run.rst
+++ b/docs/manpages/virt-qemu-run.rst
@@ -71,6 +71,12 @@ is a path to the XML description of the secret, whose UUID should
 match a secret referenced in the guest domain XML. The ``VALUE-FILE``
 is a path containing the raw value of the secret.
 
+``-c``, ``--with-config``
+
+Copy the libvirt qemu.conf configuration to the root directory.  If
+there is already a qemu.conf file in the $ROOT/etc directory, exit
+with failure.
+
 EXIT STATUS
 ===========
 
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 88fea4fc43..cb2b279401 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1899,7 +1899,6 @@ virConfWalk;
 virConfWriteFile;
 virConfWriteMem;
 
-
 # util/vircrypto.h
 virCryptoEncryptData;
 virCryptoHashBuf;
diff --git a/src/qemu/qemu_shim.c b/src/qemu/qemu_shim.c
index 7e87b8fb96..553a37ab60 100644
--- a/src/qemu/qemu_shim.c
+++ b/src/qemu/qemu_shim.c
@@ -24,6 +24,7 @@
 #include <stdbool.h>
 #include <unistd.h>
 
+#include "virconf.h"
 #include "virfile.h"
 #include "virstring.h"
 #include "virgettext.h"
@@ -99,6 +100,7 @@ int main(int argc, char **argv)
     g_auto(GStrv) secrets = NULL;
     gboolean verbose = false;
     gboolean debug = false;
+    gboolean with_config = false;
     GStrv tmpsecrets;
     GOptionContext *ctx;
     GOptionEntry entries[] = {
@@ -106,6 +108,7 @@ int main(int argc, char **argv)
         { "root", 'r', 0, G_OPTION_ARG_STRING, &root, "Root directory", "DIR" },
         { "debug", 'd', 0, G_OPTION_ARG_NONE, &debug, "Debug output", NULL },
         { "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose, "Verbose output", NULL },
+        { "with-config", 'c', 0, G_OPTION_ARG_NONE, &with_config, "Use system/home qemu.conf", NULL },
         { 0 }
     };
     int quitfd[2] = {-1, -1};
@@ -167,6 +170,39 @@ int main(int argc, char **argv)
         }
     }
 
+    if (with_config) {
+        g_autofree char *src = virConfLoadConfigPath("qemu.conf");
+        g_autofree char *dir = g_build_filename(root, "etc", NULL);
+        g_autofree char *dst = g_build_filename(dir, "qemu.conf", NULL);
+        g_autofree char *contents = NULL;
+        gsize len;
+
+        if (g_mkdir_with_parents(dir, 0755) < 0) {
+            g_printerr("%s: cannot create %s dir: %s\n",
+                       argv[0], dir, g_strerror(errno));
+            goto cleanup;
+        }
+
+
+        if (g_file_test(dst, G_FILE_TEST_EXISTS)) {
+            g_printerr("%s: %s file already exists\n",
+                       argv[0], dst);
+            goto cleanup;
+        }
+
+        if (!g_file_get_contents(src, &contents, &len, &error)) {
+            g_printerr("%s: cannot read %s: %s\n",
+                       argv[0], src, error->message);
+            goto cleanup;
+        }
+
+        if (!g_file_set_contents(dst, contents, len, &error)) {
+            g_printerr("%s: cannot write %s: %s\n",
+                       argv[0], dst, error->message);
+            goto cleanup;
+        }
+    }
+
     virFileActivateDirOverrideForProg(argv[0]);
 
     if (verbose)
-- 
2.26.0.rc2.42.g98cedd0233