Add helpers for resolving path to resources in build tree

Add virFileFindResource which will try to locate files
in the local build tree if the calling binary (eg libvirtd or
test suite) is being run from the build tree. The corresponding
virFileActivateDirOverride should be called at startup passing
in argv[0]. This will be examined for evidence of libtool magic
binary prefix / sub-directory in order to activate the override.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

diff --git a/src/Makefile.am b/src/Makefile.am
index 21d56fc74f9a992e9b685550760fc69b6a76aa77..5fb9e88b038efec034f66865e99a8f7768d77c22 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -18,6 +18,7 @@
 
 # old automake does not provide abs_{src,build}dir variables
 abs_builddir = $(shell pwd)
+abs_topbuilddir = $(shell cd .. && pwd)
 abs_srcdir = $(shell cd $(srcdir) && pwd)
 
 # No libraries with the exception of LIBXML should be listed
@@ -30,6 +31,7 @@ INCLUDES =    -I../gnulib/lib                                 \
                -I$(top_srcdir)/include                         \
                -I$(top_srcdir)/src/util                        \
                -DIN_LIBVIRT                                    \
+               -Dabs_topbuilddir="\"$(abs_topbuilddir)\""      \
                $(GETTEXT_CPPFLAGS)
 
 AM_CFLAGS =    $(LIBXML_CFLAGS)                                \

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 4cee2eb06dd6a05fc17276baa2705601c97642d1..9919ca40f9daf2606d4482b1400c1ad01c1bcd0e 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1222,6 +1222,7 @@ virBuildPathInternal;
 virDirCreate;
 virFileAbsPath;
 virFileAccessibleAs;
+virFileActivateDirOverride;
 virFileBuildPath;
 virFileClose;
 virFileDeleteTree;
@@ -1230,6 +1231,8 @@ virFileExists;
 virFileFclose;
 virFileFdopen;
 virFileFindMountPoint;
+virFileFindResource;
+virFileFindResourceFull;
 virFileGetMountReverseSubtree;
 virFileGetMountSubtree;
 virFileHasSuffix;

diff --git a/src/util/virfile.c b/src/util/virfile.c
index cffcbc1b709c057d1951dbceae0afe489dd1a1f9..4e2ff328100400edc5f5d4df562fc3b3dbf2217c 100644 (file)
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -1542,6 +1542,93 @@ virFindFileInPath(const char *file)
     return fullpath;
 }
 
+
+static bool useDirOverride;
+
+/**
+ * virFileFindResourceFull:
+ * @filename: libvirt distributed filename without any path
+ * @prefix: optional string to prepend to filename
+ * @suffix: optional string to append to filename
+ * @builddir: location of the binary in the source tree build tree
+ * @installdir: location of the installed binary
+ * @envname: environment variable used to override all dirs
+ *
+ * A helper which will return a path to @filename within
+ * the current build tree, if the calling binary is being
+ * run from the source tree. Otherwise it will return the
+ * path in the installed location.
+ *
+ * If @envname is non-NULL it will override all other
+ * directory lookup
+ *
+ * Only use this with @filename files that are part of
+ * the libvirt tree, not 3rd party binaries/files.
+ *
+ * Returns the resolved path (caller frees) or NULL on error
+ */
+char *
+virFileFindResourceFull(const char *filename,
+                        const char *prefix,
+                        const char *suffix,
+                        const char *builddir,
+                        const char *installdir,
+                        const char *envname)
+{
+    char *ret = NULL;
+    const char *envval = envname ? virGetEnvBlockSUID(envname) : NULL;
+
+    if (!prefix)
+        prefix = "";
+    if (!suffix)
+        suffix = "";
+
+    if (envval) {
+        if (virAsprintf(&ret, "%s/%s%s%s", envval, prefix, filename, suffix) < 0)
+            return NULL;
+    } else if (useDirOverride) {
+        if (virAsprintf(&ret, "%s/%s/%s%s%s", abs_topbuilddir, builddir, prefix, filename, suffix) < 0)
+            return NULL;
+    } else {
+        if (virAsprintf(&ret, "%s/%s%s%s", installdir, prefix, filename, suffix) < 0)
+            return NULL;
+    }
+
+    VIR_DEBUG("Resolved '%s' to '%s'", filename, ret);
+    return ret;
+}
+
+char *
+virFileFindResource(const char *filename,
+                    const char *builddir,
+                    const char *installdir)
+{
+    return virFileFindResourceFull(filename, NULL, NULL, builddir, installdir, NULL);
+}
+
+
+/**
+ * virFileActivateDirOverride:
+ * @argv0: argv[0] of the calling program
+ *
+ * Look at @argv0 and try to detect if running from
+ * a build directory, by looking for a 'lt-' prefix
+ * on the binary name, or '/.libs/' in the path
+ */
+void
+virFileActivateDirOverride(const char *argv0)
+{
+    char *file = strrchr(argv0, '/');
+    if (!file || file[1] == '\0')
+        return;
+    file++;
+    if (STRPREFIX(file, "lt-") ||
+        strstr(argv0, "/.libs/")) {
+        useDirOverride = true;
+        VIR_DEBUG("Activating build dir override for %s", argv0);
+    }
+}
+
 bool
 virFileIsDir(const char *path)
 {

diff --git a/src/util/virfile.h b/src/util/virfile.h
index 46ef781479e560d75c3825dbc79ac7d344645fb5..5d0d6995d244a5f23fff2ed30a3571ab18b2e8af 100644 (file)
--- a/src/util/virfile.h
+++ b/src/util/virfile.h
@@ -160,6 +160,20 @@ int virFileIsLink(const char *linkpath)
 
 char *virFindFileInPath(const char *file);
 
+char *virFileFindResource(const char *filename,
+                          const char *builddir,
+                          const char *installdir)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
+char *virFileFindResourceFull(const char *filename,
+                              const char *prefix,
+                              const char *suffix,
+                              const char *builddir,
+                              const char *installdir,
+                              const char *envname)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(5);
+void virFileActivateDirOverride(const char *argv0)
+    ATTRIBUTE_NONNULL(1);
+
 bool virFileIsDir (const char *file) ATTRIBUTE_NONNULL(1);
 bool virFileExists(const char *file) ATTRIBUTE_NONNULL(1);
 bool virFileIsExecutable(const char *file) ATTRIBUTE_NONNULL(1);