bin/58133: back port libmap.conf feature for 4-stable

Norikatsu Shigemura nork at FreeBSD.org
Thu Oct 16 09:10:25 PDT 2003


>Number:         58133
>Category:       bin
>Synopsis:       back port libmap.conf feature for 4-stable
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Thu Oct 16 09:10:16 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Norikatsu Shigemura
>Release:        FreeBSD 4.9-RC i386
>Organization:
Ensure Technology Ltd. (http://www.ensure-tech.co.jp)
>Environment:
System: FreeBSD sakura.ninth-nine.com 4.9-RC FreeBSD 4.9-RC #3: Fri Oct 3 15:57:33 JST 2003 nork at sakura.ninth-nine.com:/usr/obj/usr/src/sys/SAKURA i386
>Description:
	I back-port-ed /etc/libmap.conf feature on 5-current written
	by mdodd@ to 4-stable.  I requested mdodd@ to back port this
	feature.  But mdodd@ said following lines and didn't have
	mdodd@'s heart in it.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Subject: Re: /etc/libmap.conf MFC?
Date: Fri, 20 Jun 2003 18:10:57 -0400 (EDT)
on freebsd-stable@, mdodd said,
You should upgrade to 5.1 if it has features that you want.
Adding new features to the STABLE branch this late in its lifetime
seems pointless.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>How-To-Repeat:
	N/A
>Fix:
--- libmap_4stable.diff begins here ---
diff -urN libexec/rtld-elf.old/Makefile libexec/rtld-elf/Makefile
--- libexec/rtld-elf.old/Makefile	Sun Jun 23 06:32:35 2002
+++ libexec/rtld-elf/Makefile	Wed Oct  8 02:50:10 2003
@@ -2,7 +2,7 @@
 
 PROG=		ld-elf.so.1
 SRCS=		rtld_start.S rtld.c lockdflt.c map_object.c malloc.c \
-		xmalloc.c debug.c reloc.c
+		xmalloc.c debug.c reloc.c libmap.c
 MAN=		rtld.1
 CFLAGS+=	-Wall -DFREEBSD_ELF -I${.CURDIR}/${MACHINE_ARCH} -I${.CURDIR}
 LDFLAGS+=	-nostdlib -e .rtld_start
diff -urN libexec/rtld-elf.old/libmap.c libexec/rtld-elf/libmap.c
--- libexec/rtld-elf.old/libmap.c	Thu Jan  1 09:00:00 1970
+++ libexec/rtld-elf/libmap.c	Wed Oct  8 02:44:17 2003
@@ -0,0 +1,255 @@
+/*
+ * $FreeBSD: src/libexec/rtld-elf/libmap.c,v 1.9 2003/09/13 21:43:08 mdodd Exp $
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/queue.h>
+#include <sys/param.h>
+
+#include "debug.h"
+#include "rtld.h"
+#include "libmap.h"
+
+#ifndef _PATH_LIBMAP_CONF
+#define	_PATH_LIBMAP_CONF	"/etc/libmap.conf"
+#endif
+
+TAILQ_HEAD(lm_list, lm);
+struct lm {
+	char *f;
+	char *t;
+
+	TAILQ_ENTRY(lm)	lm_link;
+};
+
+TAILQ_HEAD(lmp_list, lmp) lmp_head = TAILQ_HEAD_INITIALIZER(lmp_head);
+struct lmp {
+	char *p;
+	struct lm_list lml;
+	TAILQ_ENTRY(lmp) lmp_link;
+};
+
+static void		lm_add		(const char *, const char *, const char *);
+static void		lm_free		(struct lm_list *);
+static char *		lml_find	(struct lm_list *, const char *);
+static struct lm_list *	lmp_find	(const char *);
+static struct lm_list *	lmp_init	(char *);
+
+#define	iseol(c)	(((c) == '#') || ((c) == '\0') || \
+			 ((c) == '\n') || ((c) == '\r'))
+
+int
+lm_init (void)
+{
+	FILE	*fp;
+	char	*cp;
+	char	*f, *t, *p, *c;
+	char	prog[MAXPATHLEN];
+	char	line[MAXPATHLEN + 2];
+
+	dbg("%s()", __func__);
+
+	TAILQ_INIT(&lmp_head);
+
+	if ((fp = fopen(_PATH_LIBMAP_CONF, "r")) == NULL)
+		return (1);
+
+	p = NULL;
+	while ((cp = fgets(line, MAXPATHLEN + 1, fp)) != NULL) {
+		t = f = c = NULL;
+
+		/* Skip over leading space */
+		while (isspace(*cp)) cp++;
+
+		/* Found a comment or EOL */
+		if (iseol(*cp)) continue;
+
+		/* Found a constraint selector */
+		if (*cp == '[') {
+			cp++;
+
+			/* Skip leading space */
+			while (isspace(*cp)) cp++;
+
+			/* Found comment, EOL or end of selector */
+			if  (iseol(*cp) || *cp == ']')
+				continue;
+
+			c = cp++;
+			/* Skip to end of word */
+			while (!isspace(*cp) && !iseol(*cp) && *cp != ']')
+				cp++;
+
+			/* Skip and zero out trailing space */
+			while (isspace(*cp)) *cp++ = '\0';
+
+			/* Check if there is a closing brace */
+			if (*cp != ']') continue;
+
+			/* Terminate string if there was no trailing space */
+			*cp++ = '\0';
+
+			/*
+			 * There should be nothing except whitespace or comment
+			  from this point to the end of the line.
+			 */
+			while(isspace(*cp)) *cp++;
+			if (!iseol(*cp)) continue;
+
+			strcpy(prog, c);
+			p = prog;
+			continue;
+		}
+
+		/* Parse the 'from' candidate. */
+		f = cp++;
+		while (!isspace(*cp) && !iseol(*cp)) cp++;
+
+		/* Skip and zero out the trailing whitespace */
+		while (isspace(*cp)) *cp++ = '\0';
+
+		/* Found a comment or EOL */
+		if (iseol(*cp)) continue;
+
+		/* Parse 'to' mapping */
+		t = cp++;
+		while (!isspace(*cp) && !iseol(*cp)) cp++;
+
+		/* Skip and zero out the trailing whitespace */
+		while (isspace(*cp)) *cp++ = '\0';
+
+		/* Should be no extra tokens at this point */
+		if (!iseol(*cp)) continue;
+
+		*cp = '\0';
+		lm_add(p, f, t);
+	}
+	fclose(fp);
+	return (0);
+}
+
+static void
+lm_free (struct lm_list *lml)
+{
+	struct lm *lm;
+
+	dbg("%s(%p)", __func__, lml);
+
+	while (!TAILQ_EMPTY(lml)) {
+		lm = TAILQ_FIRST(lml);
+		TAILQ_REMOVE(lml, lm, lm_link);
+		free(lm->f);
+		free(lm->t);
+		free(lm);
+	}
+	return;
+}
+
+void
+lm_fini (void)
+{
+	struct lmp *lmp;
+
+	dbg("%s()", __func__);
+
+	while (!TAILQ_EMPTY(&lmp_head)) {
+		lmp = TAILQ_FIRST(&lmp_head);
+		TAILQ_REMOVE(&lmp_head, lmp, lmp_link);
+		free(lmp->p);
+		lm_free(&lmp->lml);
+		free(lmp);
+	}
+	return;
+}
+
+static void
+lm_add (const char *p, const char *f, const char *t)
+{
+	struct lm_list *lml;
+	struct lm *lm;
+
+	if (p == NULL)
+		p = "$DEFAULT$";
+
+	dbg("%s(\"%s\", \"%s\", \"%s\")", __func__, p, f, t);
+
+	if ((lml = lmp_find(p)) == NULL)
+		lml = lmp_init(xstrdup(p));
+
+	lm = xmalloc(sizeof(struct lm));
+	lm->f = xstrdup(f);
+	lm->t = xstrdup(t);
+	TAILQ_INSERT_HEAD(lml, lm, lm_link);
+}
+
+char *
+lm_find (const char *p, const char *f)
+{
+	struct lm_list *lml;
+	char *t;
+
+	dbg("%s(\"%s\", \"%s\")", __func__, p, f);
+
+	if (p != NULL && (lml = lmp_find(p)) != NULL) {
+		t = lml_find(lml, f);
+		if (t != NULL) {
+			/*
+			 * Add a global mapping if we have
+			 * a successful constrained match.
+			 */
+			lm_add(NULL, f, t);
+			return (t);
+		}
+	}
+	lml = lmp_find("$DEFAULT$");
+	if (lml != NULL)
+		return (lml_find(lml, f));
+	else
+		return (NULL);
+}
+
+static char *
+lml_find (struct lm_list *lmh, const char *f)
+{
+	struct lm *lm;
+
+	dbg("%s(%p, \"%s\")", __func__, lmh, f);
+
+	TAILQ_FOREACH(lm, lmh, lm_link)
+		if ((strncmp(f, lm->f, strlen(lm->f)) == 0) &&
+		    (strlen(f) == strlen(lm->f)))
+			return (lm->t);
+	return NULL;
+}
+
+static struct lm_list *
+lmp_find (const char *n)
+{
+	struct lmp *lmp;
+
+	dbg("%s(\"%s\")", __func__, n);
+
+	TAILQ_FOREACH(lmp, &lmp_head, lmp_link)
+		if ((strncmp(n, lmp->p, strlen(lmp->p)) == 0) &&
+		    (strlen(n) == strlen(lmp->p)))
+			return (&lmp->lml);
+	return (NULL);
+}
+
+static struct lm_list *
+lmp_init (char *n)
+{
+	struct lmp *lmp;
+
+	dbg("%s(\"%s\")", __func__, n);
+
+	lmp = xmalloc(sizeof(struct lmp));
+	lmp->p = n;
+	TAILQ_INIT(&lmp->lml);
+	TAILQ_INSERT_HEAD(&lmp_head, lmp, lmp_link);
+
+	return (&lmp->lml);
+}
diff -urN libexec/rtld-elf.old/libmap.h libexec/rtld-elf/libmap.h
--- libexec/rtld-elf.old/libmap.h	Thu Jan  1 09:00:00 1970
+++ libexec/rtld-elf/libmap.h	Wed Oct  8 02:44:17 2003
@@ -0,0 +1,7 @@
+/*
+ * $FreeBSD: src/libexec/rtld-elf/libmap.h,v 1.2 2003/09/13 21:43:08 mdodd Exp $
+ */
+
+int	lm_init (void);
+void	lm_fini (void);
+char *	lm_find (const char *, const char *);
diff -urN libexec/rtld-elf.old/rtld.1 libexec/rtld-elf/rtld.1
--- libexec/rtld-elf.old/rtld.1	Sat Jan 12 02:35:52 2002
+++ libexec/rtld-elf/rtld.1	Wed Oct  8 02:50:10 2003
@@ -88,6 +88,9 @@
 other shared libraries.
 If the directory is not specified then
 the directories specified by
+.It Ev LD_LIBMAP_DISABLE
+If set, disables the use of
+.Xr libmap.conf 5 .
 .Ev LD_LIBRARY_PATH
 will be searched first
 followed by the set of built-in standard directories.
@@ -147,9 +150,12 @@
 .Sh FILES
 .Bl -tag -width indent
 .It Pa /var/run/ld-elf.so.hints
+.It Pa /etc/libmap.conf
+The libmap configuration file.
 .El
 .Sh SEE ALSO
 .Xr ld 1 ,
 .Xr ldd 1 ,
 .Xr elf 5 ,
+.Xr libmap.conf 5 ,
 .Xr ldconfig 8
diff -urN libexec/rtld-elf.old/rtld.c libexec/rtld-elf/rtld.c
--- libexec/rtld-elf.old/rtld.c	Sat Feb 22 00:50:43 2003
+++ libexec/rtld-elf/rtld.c	Wed Oct  8 02:50:10 2003
@@ -52,6 +52,7 @@
 
 #include "debug.h"
 #include "rtld.h"
+#include "libmap.h"
 
 #define END_SYM		"_end"
 #define PATH_RTLD	"/usr/libexec/ld-elf.so.1"
@@ -131,6 +132,7 @@
  */
 static char *error_message;	/* Message for dlerror(), or NULL */
 struct r_debug r_debug;		/* for GDB; */
+static bool libmap_disable;	/* Disable libmap */
 static bool trust;		/* False for setuid and setgid programs */
 static char *ld_bind_now;	/* Environment variable for immediate binding */
 static char *ld_debug;		/* Environment variable for debugging */
@@ -293,6 +295,7 @@
     ld_bind_now = getenv("LD_BIND_NOW");
     if (trust) {
 	ld_debug = getenv("LD_DEBUG");
+	libmap_disable = getenv("LD_LIBMAP_DISABLE") != NULL;
 	ld_library_path = getenv("LD_LIBRARY_PATH");
 	ld_preload = getenv("LD_PRELOAD");
     }
@@ -366,6 +369,9 @@
     sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
     sym_zero.st_shndx = SHN_ABS;
 
+    if (!libmap_disable)
+	libmap_disable = (bool)lm_init();
+
     dbg("loading LD_PRELOAD libraries");
     if (load_preload_objects() == -1)
 	die();
@@ -791,19 +797,24 @@
  *   /usr/lib
  */
 static char *
-find_library(const char *name, const Obj_Entry *refobj)
+find_library(const char *xname, const Obj_Entry *refobj)
 {
     char *pathname;
+    char *name;
 
-    if (strchr(name, '/') != NULL) {	/* Hard coded pathname */
-	if (name[0] != '/' && !trust) {
+    if (strchr(xname, '/') != NULL) {	/* Hard coded pathname */
+	if (xname[0] != '/' && !trust) {
 	    _rtld_error("Absolute pathname required for shared object \"%s\"",
-	      name);
+	      xname);
 	    return NULL;
 	}
-	return xstrdup(name);
+	return xstrdup(xname);
     }
 
+    if (libmap_disable || (refobj == NULL) ||
+		(name = lm_find(refobj->path, xname)) == NULL)
+	name = (char *)xname;
+
     dbg(" Searching for \"%s\"", name);
 
     if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
@@ -1433,6 +1444,8 @@
 	obj->refcount = 0;
     objlist_call_fini(&list_fini);
     /* No need to remove the items from the list, since we are exiting. */
+    if (!libmap_disable)
+	lm_fini();
 }
 
 static void *
--- libmap_4stable.diff ends here ---


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