Fix permissions problems: the directory will now always be created mode 2755. In addition, the temporary file is giv...

Original commit message from CVS:
Fix permissions problems: the directory will now always be created mode
2755.  In addition, the temporary file is given restricted permissions, and
the permissions on the registry file are preserved if one already exists,
or 666 (and modified by the umask) if one doesn't already exist.

tools/gstreamer-register.c

@@ -39,6 +39,16 @@
 #define GLOBAL_REGISTRY_FILE     GLOBAL_REGISTRY_DIR"/reg.xml"
 #define GLOBAL_REGISTRY_FILE_TMP GLOBAL_REGISTRY_DIR"/.reg.xml.tmp"
 
+#define REGISTRY_DIR_PERMS (S_ISGID | \
+			    S_IRUSR | S_IWUSR | S_IXUSR | \
+			    S_IRGRP | S_IXGRP | \
+			    S_IROTH | S_IXOTH)
+#define REGISTRY_TMPFILE_PERMS (S_IRUSR | S_IWUSR)
+#define REGISTRY_FILE_PERMS (S_IRUSR | S_IWUSR | \
+			     S_IRGRP | S_IWGRP | \
+			     S_IROTH | S_IWOTH)
+
+
 extern gboolean _gst_plugin_spew;
 extern gboolean _gst_warn_old_registry;
 
@@ -69,13 +79,29 @@ static int is_dir(const char * filename) {
   return S_ISDIR(statbuf.st_mode);
 }
 
-static void move_file(const char * nameold, const char * namenew) {
+static void set_filemode(const char * filename, mode_t mode) {
+    if(chmod(filename, mode)) {
+	g_print("Cannot set file permissions on `%s' to %o", filename, mode);
+	error_perm();
+    }
+}
+
+static int get_filemode(const char * filename, mode_t * mode) {
+    struct stat statbuf;
+    if(stat(filename, &statbuf)) return 0;
+    *mode = statbuf.st_mode & ~ S_IFMT;
+    return 1;
+}
+
+static void move_file(const char * nameold,
+		      const char * namenew,
+		      mode_t * newmode) {
     if (!is_file(nameold)) {
 	g_print("Temporary `%s' is not a file", nameold);
 	error_perm();
     }
     if (is_dir(namenew)) {
-	g_print("Destination path `%s' is a directory\n", namenew);
+	g_print("Destination path `%s' for registry file is a directory\n", namenew);
 	g_print("Please remove, or reconfigure GStreamer\n\n");
 	exit(1);
     }
@@ -83,46 +109,68 @@ static void move_file(const char * nameold, const char * namenew) {
 	g_print("Cannot move `%s' to `%s'", nameold, namenew);
 	error_perm();
     }
+    // set mode again, to make this public
+    set_filemode(namenew, *newmode);
 }
 
-static int make_dir(const char * dirname) {
-    mode_t mode = 0777;
-    return !mkdir(dirname, mode);
+static void make_dir(const char * dirname) {
+    mode_t mode = REGISTRY_DIR_PERMS;
+    if(mkdir(dirname, mode)) {
+	g_print("Cannot create GStreamer registry directory `%s'", dirname);
+	error_perm();
+    }
+
+    if(chmod(dirname, mode)) {
+	g_print("Cannot set permissions on GStreamer registry directory `%s' to %o", dirname, mode);
+	error_perm();
+    }
+
+    return;
 }
 
 static void check_dir(const char * dirname) {
     if (!is_dir(dirname)) {
-	if (!make_dir(dirname)) {
-	    g_print("Cannot create GStreamer registry directory `%s'",
-		    dirname);
-	    error_perm();
-	}
+	make_dir(dirname);
     }
 }
 
-static void save_registry(const char *destfile, xmlDocPtr * doc) {
+static void save_registry(const char *destfile,
+			  xmlDocPtr * doc) {
+    mode_t tmpmode = REGISTRY_TMPFILE_PERMS;
 #if 0
     FILE *fp;
+    int fd;
 
-    fp = fopen (destfile, "w");
-    if (!fp) {
+    fd = open(destfile, O_CREAT | O_TRUNC | O_WRONLY, tmpmode);
+    if (fd == -1) {
 	g_print("Cannot open `%s' to save new registry to.", destfile);
 	error_perm();
     }
+    fp = fdopen (fd, "wb");
+    if (!fp) {
+	g_print("Cannot fopen `%s' to save new registry to.", destfile);
+	error_perm();
+    }
+    // set mode to make this private
+    set_filemode(destfile, tmpmode);
 
     // FIXME: no way to check success of xmlDocDump, which is why
     // this piece of code is ifdefed out.
+    // The version of libxml currently (Jan 2001) in their CVS tree fixes
+    // this problem. 
     xmlDocDump(fp, *doc);
 
     if (!fclose(fp)) {
 	g_print("Cannot close `%s' having saved new registry.", destfile);
 	error_perm();
     }
+
 #else
     if (xmlSaveFile(destfile, *doc) <= 0) {
 	g_print("Cannot save new registry to `%s'", destfile);
 	error_perm();
     }
+    set_filemode(destfile, tmpmode);
 #endif
 }
 
@@ -130,8 +178,19 @@ int main(int argc,char *argv[])
 {
     xmlDocPtr doc;
 
+    // Mode of the file we're saving the repository to;
+    mode_t newmode;
+
+    // Get mode of old repository, or a default.
+    if (!get_filemode(GLOBAL_REGISTRY_FILE, &newmode)) {
+	mode_t theumask = umask(0);
+	umask(theumask);
+	newmode = REGISTRY_FILE_PERMS & ~ theumask;
+    }
+
     // remove the old registry file first
-    // FIXME this could fail, at which point we're spinning
+    // If this fails, we simply ignore it since we'll overwrite it later
+    // anyway.
     unlink(GLOBAL_REGISTRY_FILE);
 
     // Init gst
@@ -155,7 +214,7 @@ int main(int argc,char *argv[])
     save_registry(GLOBAL_REGISTRY_FILE_TMP, &doc);
 
     // Make the tmp file live.
-    move_file(GLOBAL_REGISTRY_FILE_TMP, GLOBAL_REGISTRY_FILE);
+    move_file(GLOBAL_REGISTRY_FILE_TMP, GLOBAL_REGISTRY_FILE, &newmode);
 
     return(0);
 }