PERFORCE change 174218 for review

[Robert Watson]

http://p4web.freebsd.org/chv.cgi?CH=174218

Change 174218 by rwatson at rwatson_vimage_client on 2010/02/03 10:34:01

	Keep a running count of valid file descriptors in the directory
	length array, rather than marking unused ones as (-1).  This avoids
	several loops.  While here, fix a (+ sizeof(int)) into a
	(* sizeof(int)) and a few other nits.

Affected files ...

.. //depot/projects/trustedbsd/capabilities/src/libexec/rtld-elf/rtld.c#38 edit

Differences ...

==== //depot/projects/trustedbsd/capabilities/src/libexec/rtld-elf/rtld.c#38 (text+ko) ====

@@ -188,7 +188,9 @@
 static char *ld_bind_now;	/* Environment variable for immediate binding */
 static char *ld_debug;		/* Environment variable for debugging */
 static int *ld_library_dirs = NULL; /* File descriptors of lib path (end: -1) */
+static int ld_library_dirs_done; /* ld_library_dirs has been initialized */
 static int ld_library_dirlen;	/* Capacity of ld_library_dirs */
+static int ld_library_dircount;	/* Number of entries in ld_library_dirs */
 #ifndef IN_RTLD_CAP
 static char *ld_library_path;	/* Environment variable for search path */
 static char *ld_preload;	/* Environment variable for libraries to
@@ -1240,9 +1242,9 @@
 {
     int fd, i;
 
-    if (ld_library_dirs == NULL)
+    if (!ld_library_dirs_done)
 	init_libdirs();
-    for (i = 0; (i < ld_library_dirlen) && (ld_library_dirs[i] != -1); i++) {
+    for (i = 0; i < ld_library_dircount); i++) {
 	fd = openat(ld_library_dirs[i], name, O_RDONLY);
 	if (fd >= 0)
 	    return (fd);
@@ -2111,35 +2113,39 @@
 
 /*
  * Add a file descriptor to ld_library_dirs.
+ *
+ * XXX: This may be called from either the rtld startup code, or from
+ * ld_libdirs.  We have no way to distinguish them on error, so die()
+ * unconditionally.  Perhaps the latter case should allow graceful failure.
+ *
+ * XXX: Synchronization?
  */
 static void
 add_libdir_fd(int fd)
 {
-    int i;
 
-    if (ld_library_dirs == NULL) {
-	/* Initialize the FD list. */
+    /* Initialize the FD list. */
+    if (!ld_library_dirs_done) {
 	ld_library_dirlen = INITIAL_FDLEN;
+	ld_library_dircount = 0;
 	ld_library_dirs = xmalloc(ld_library_dirlen * sizeof(int));
-	memset(ld_library_dirs, 0xff, ld_library_dirlen * sizeof(int));
+	ld_library_dirs_done = 1;
     }
 
-    /* Find the next available FD slot. */
-    for (i = 0; (i < ld_library_dirlen) && (ld_library_dirs[i] != -1); i++)
-	;
-
-    if (i == ld_library_dirlen) {
-	/* We need more space. */
-	int old_size = ld_library_dirlen + sizeof(int);
-
+    /* Do we need to grow? */
+    if (ld_library_dirlen == ld_library_dircount) {
 	ld_library_dirlen *= 2;
-	ld_library_dirs = realloc(ld_library_dirs, 2 * old_size);
-	memset(ld_library_dirs + old_size, 0xff, old_size);
+	ld_library_dirs = realloc(ld_library_dirs,
+	    ld_library_dirlen * sizeof(int));
+	if (ld_library_dirs == NULL) {
+	    _rtld_error("add_libdir_fd: realloc failed");
+	    die();
+	}
+    }
 
-	if (ld_library_dirs == NULL)
-	    err(-1, "realloc() failed");
-    }
-    ld_library_dirs[i] = fd;
+    /* Add the new library directory fd to the end. */
+    ld_library_dirs[ld_library_dircount] = fd;
+    ld_library_dircount++;
 }
 
 /*
@@ -2204,12 +2210,6 @@
     add_libdir_paths(gethints());
     add_libdir_paths(STANDARD_LIBRARY_PATH);
 #endif
-
-    /* If all else fails, create an empty array */
-    if (ld_library_dirlen == 0) {
-	ld_library_dirs = malloc(sizeof(int));
-	ld_library_dirs[0] = -1;
-    }
 }
 
 /*
@@ -2220,7 +2220,6 @@
 int
 ld_libdirs(int *fds, int *fdcount)
 {
-    int i = 0;
 
     if (fdcount == NULL)
 	return (-1);
@@ -2228,16 +2227,14 @@
 	*fdcount = -1;
 	return (-1);
     }
-    if (ld_library_dirs == NULL)
+    if (!ld_library_dirs_done)
 	init_libdirs();
-    for (i = 0; (i < ld_library_dirlen) && (ld_library_dirs[i] != -1); i++)
-	;
-    if (*fdcount < i) {
-	*fdcount = i;
+    if (*fdcount < ld_library_dircount) {
+	*fdcount = ld_library_dircount;
 	return (-1);
     }
-    *fdcount = i;
-    memcpy(fds, ld_library_dirs, i * sizeof(int));
+    *fdcount = ld_library_dircount;
+    memcpy(fds, ld_library_dirs, ld_library_dircount * sizeof(int));
     return (0);
 }