[Qemu-devel] [PATCH] Add optional dump of default config file paths..

[john cooper]

This patch adds the ability to determine the build-configured
runtime "config file" paths from the command line.  After
support for cpu model definitions were added to the default
runtime "target-" config file, testing of this feature has
tripped over an unintentionally mis-installed config file
enough to indicate some help is needed resolving such issues.

As no general "verbose" flag is currently available, specifying
"-readconfig ?" on the command line will maintain the default
(config file) disposition but additionally emit diagnostic info.
This mode is optional, otherwise the existing startup behavior
is identical.

Signed-off-by: john cooper <john.coo...@redhat.com>
---

diff --git a/qemu-config.c b/qemu-config.c
index 5a4e61b..a490603 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -518,21 +518,29 @@ out:
     return res;
 }
 
-int qemu_read_config_file(const char *filename)
+/* attempt to open and parse config file, report problems if vflag
+ */
+int qemu_read_config_file(const char *filename, int vflag)
 {
     FILE *f = fopen(filename, "r");
-    int ret;
+    int rv = 0;
 
     if (f == NULL) {
-        return -errno;
+        rv = -errno;
     }
-
-    ret = qemu_config_parse(f, vm_config_groups, filename);
-    fclose(f);
-
-    if (ret == 0) {
-        return 0;
-    } else {
-        return -EINVAL;
+    else if (qemu_config_parse(f, vm_config_groups, filename) != 0) {
+        rv = -EINVAL;
+    }
+    else if (vflag) {
+        fprintf(stderr, "read config file %s\n", filename);
     }
+    if (f) {
+        fclose(f);
+    }
+    if (rv && vflag) {
+        fprintf(stderr, "can't read config file %s: %s\n",
+                filename, strerror(-rv));
+    }
+    return rv;
 }
+
diff --git a/qemu-config.h b/qemu-config.h
index dca69d4..2e15556 100644
--- a/qemu-config.h
+++ b/qemu-config.h
@@ -23,6 +23,6 @@ void qemu_add_globals(void);
 void qemu_config_write(FILE *fp);
 int qemu_config_parse(FILE *fp, QemuOptsList **lists, const char *fname);
 
-int qemu_read_config_file(const char *filename);
+int qemu_read_config_file(const char *filename, int vflag);
 
 #endif /* QEMU_CONFIG_H */
diff --git a/vl.c b/vl.c
index 7121cd0..23c7276 100644
--- a/vl.c
+++ b/vl.c
@@ -2582,6 +2582,7 @@ int main(int argc, char **argv, char **envp)
 #endif
     int show_vnc_port = 0;
     int defconfig = 1;
+    int defconfig_verbose = 0; 
 
     error_set_progname(argv[0]);
 
@@ -2657,6 +2658,10 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_nodefconfig:
                 defconfig=0;
                 break;
+            case QEMU_OPTION_readconfig:
+                if (!strcmp(optarg, "?"))
+                    defconfig_verbose = 1;
+                break;
             }
         }
     }
@@ -2664,12 +2669,14 @@ int main(int argc, char **argv, char **envp)
     if (defconfig) {
         int ret;
 
-        ret = qemu_read_config_file(CONFIG_QEMU_CONFDIR "/qemu.conf");
+        ret = qemu_read_config_file(CONFIG_QEMU_CONFDIR "/qemu.conf",
+                                    defconfig_verbose);
         if (ret < 0 && ret != -ENOENT) {
             exit(1);
         }
 
-        ret = qemu_read_config_file(arch_config_name);
+        ret = qemu_read_config_file(arch_config_name,
+                                    defconfig_verbose);
         if (ret < 0 && ret != -ENOENT) {
             exit(1);
         }
@@ -3386,15 +3393,9 @@ int main(int argc, char **argv, char **envp)
                 xen_mode = XEN_ATTACH;
                 break;
             case QEMU_OPTION_readconfig:
-                {
-                    int ret = qemu_read_config_file(optarg);
-                    if (ret < 0) {
-                        fprintf(stderr, "read config %s: %s\n", optarg,
-                            strerror(-ret));
-                        exit(1);
-                    }
-                    break;
-                }
+                if (!defconfig_verbose && qemu_read_config_file(optarg, 1) < 0)
+                    exit(1);
+                break;
             case QEMU_OPTION_writeconfig:
                 {
                     FILE *fp;

-- 
john.coo...@redhat.com