[Pkg-libvirt-commits] [libguestfs] 44/63: daemon: add a way to check for the version of augeas

[Hilko Bengen]

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bengen pushed a commit to annotated tag debian/1%1.27.39-1
in repository libguestfs.

commit d01fbe86662860b3e7fef8b76a8ba9579669c8af
Author: Pino Toscano <ptoscano at redhat.com>
Date:   Fri Sep 5 14:47:22 2014 +0200

    daemon: add a way to check for the version of augeas
    
    Query augeas for its version when required, i.e. only once when using
    the new augeas_is_version function.
---
 daemon/augeas.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 daemon/daemon.h | 16 ++++++++++++++-
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/daemon/augeas.c b/daemon/augeas.c
index 74f3ba7..9c8bbcc 100644
--- a/daemon/augeas.c
+++ b/daemon/augeas.c
@@ -29,12 +29,73 @@
 #include "actions.h"
 #include "optgroups.h"
 
+#define FPRINTF_AUGEAS_ERROR(aug,fs,...)                                \
+  do {                                                                  \
+    int code = aug_error (aug);                                         \
+    if (code == AUG_ENOMEM)                                             \
+      reply_with_error (fs ": augeas out of memory", ##__VA_ARGS__);    \
+    else {                                                              \
+      const char *message = aug_error_message (aug);                    \
+      const char *minor = aug_error_minor_message (aug);                \
+      const char *details = aug_error_details (aug);                    \
+      fprintf (stderr, fs ": %s%s%s%s%s", ##__VA_ARGS__,                \
+                          message,                                      \
+                          minor ? ": " : "", minor ? minor : "",        \
+                          details ? ": " : "", details ? details : ""); \
+    }                                                                   \
+  } while (0)
+
+int augeas_version;
+
 /* The Augeas handle.  We maintain a single handle per daemon, which
  * is all that is necessary and reduces the complexity of the API
  * considerably.
  */
 static augeas *aug = NULL;
 
+void
+aug_read_version (void)
+{
+  CLEANUP_AUG_CLOSE augeas *ah = NULL;
+  int r;
+  const char *str;
+  int major = 0, minor = 0, patch = 0;
+
+  if (augeas_version != 0)
+    return;
+
+  /* Optimization: do not load the files nor the lenses, since we are
+   * only interested in the version.
+   */
+  ah = aug_init ("/", NULL, AUG_NO_ERR_CLOSE | AUG_NO_LOAD | AUG_NO_STDINC);
+  if (!ah) {
+    FPRINTF_AUGEAS_ERROR (ah, "augeas initialization failed");
+    return;
+  }
+
+  if (aug_error (ah) != AUG_NOERROR) {
+    FPRINTF_AUGEAS_ERROR (ah, "aug_init");
+    return;
+  }
+
+  r = aug_get (ah, "/augeas/version", &str);
+  if (r != 1) {
+    FPRINTF_AUGEAS_ERROR (ah, "aug_get");
+    return;
+  }
+
+  r = sscanf (str, "%d.%d.%d", &major, &minor, &patch);
+  if (r != 2 && r != 3) {
+    fprintf (stderr, "cannot match the version string in '%s'\n", str);
+    return;
+  }
+
+  if (verbose)
+    fprintf (stderr, "augeas version: %d.%d.%d\n", major, minor, patch);
+
+  augeas_version = (major << 16) | (minor << 8) | patch;
+}
+
 /* Clean up the augeas handle on daemon exit. */
 void aug_finalize (void) __attribute__((destructor));
 void
diff --git a/daemon/daemon.h b/daemon/daemon.h
index b9e7402..0ccbc9e 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -228,8 +228,22 @@ extern void copy_lvm (void);
 /*-- in zero.c --*/
 extern void wipe_device_before_mkfs (const char *device);
 
-/*-- in augeas.c, hivex.c, journal.c --*/
+/*-- in augeas.c --*/
+extern void aug_read_version (void);
 extern void aug_finalize (void);
+
+/* The version of augeas, saved as:
+ * (MAJOR << 16) | (MINOR << 8) | PATCH
+ */
+extern int augeas_version;
+static inline int
+augeas_is_version (int major, int minor, int patch)
+{
+  aug_read_version (); /* Lazy version reading. */
+  return augeas_version >= ((major << 16) | (minor << 8) | patch);
+}
+
+/*-- hivex.c, journal.c --*/
 extern void hivex_finalize (void);
 extern void journal_finalize (void);
 

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