[src/trunk]: src/sys/lib/libsa Utility function to lookup a symbol value in a...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d9fdc55c4ea4
branches:  trunk
changeset: 751998:d9fdc55c4ea4
user:      martin <martin%NetBSD.org@localhost>
date:      Wed Feb 10 21:54:47 2010 +0000

description:
Utility function to lookup a symbol value in an elf symbol table - allows,
for example, a bootloader to access symbols in the just loaded kernel
(or module).

diffstat:

 sys/lib/libsa/Makefile       |   6 +-
 sys/lib/libsa/lookup_elf32.c |  94 ++++++++++++++++++++++++++++++++++++++++++++
 sys/lib/libsa/lookup_elf64.c |  33 +++++++++++++++
 3 files changed, 130 insertions(+), 3 deletions(-)

diffs (155 lines):

diff -r 2250bbb035c8 -r d9fdc55c4ea4 sys/lib/libsa/Makefile
--- a/sys/lib/libsa/Makefile    Wed Feb 10 20:54:46 2010 +0000
+++ b/sys/lib/libsa/Makefile    Wed Feb 10 21:54:47 2010 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: Makefile,v 1.70 2009/08/25 14:10:54 he Exp $
+#      $NetBSD: Makefile,v 1.71 2010/02/10 21:54:47 martin Exp $
 
 LIB=   sa
 NOPIC= # defined
@@ -45,8 +45,8 @@
 .endif
 
 .if (${SA_USE_LOADFILE} == "yes")
-SRCS+= loadfile.c loadfile_ecoff.c loadfile_elf32.c \
-       loadfile_elf64.c
+SRCS+= loadfile.c loadfile_ecoff.c loadfile_elf32.c lookup_elf32.c \
+       loadfile_elf64.c lookup_elf64.c
 .if (${MACHINE_CPU} != "mips")
 SRCS+= loadfile_aout.c
 .endif
diff -r 2250bbb035c8 -r d9fdc55c4ea4 sys/lib/libsa/lookup_elf32.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/lib/libsa/lookup_elf32.c      Wed Feb 10 21:54:47 2010 +0000
@@ -0,0 +1,94 @@
+/* $NetBSD: lookup_elf32.c,v 1.1 2010/02/10 21:54:47 martin Exp $ */
+
+/*-
+ * Copyright (c) 2010 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Martin Husemann.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* If not included by lookup_elf64.c, ELFSIZE won't be defined. */
+#ifndef ELFSIZE
+#define        ELFSIZE 32
+#endif
+
+#include <string.h>
+#include <sys/param.h>
+#include <sys/exec_elf.h>
+
+#if ((ELFSIZE == 32) && defined(BOOT_ELF32)) || \
+    ((ELFSIZE == 64) && defined(BOOT_ELF64))
+
+void *
+ELFNAMEEND(lookup_symbol)(const char *symname, void *sstab, void *estab)
+{
+       Elf_Ehdr *elf;
+       Elf_Shdr *shp;
+       Elf_Sym *symtab_start, *symtab_end, *sp;
+       char *strtab_start, *strtab_end;
+       int i, j;
+
+       elf = sstab;
+       if (elf->e_shoff == 0)
+               return NULL;
+
+       switch (elf->e_machine) {
+       ELFDEFNNAME(MACHDEP_ID_CASES)
+       default:
+               return NULL;
+       }
+
+       symtab_start = symtab_end = NULL;
+       strtab_start = strtab_end = NULL;
+
+       shp = (Elf_Shdr *)((char *)sstab + elf->e_shoff);
+       for (i = 0; i < elf->e_shnum; i++) {
+               if (shp[i].sh_type != SHT_SYMTAB)
+                       continue;
+               if (shp[i].sh_offset == 0)
+                       continue;
+               symtab_start = (Elf_Sym*)((char*)sstab + shp[i].sh_offset);
+               symtab_end = (Elf_Sym*)((char*)sstab + shp[i].sh_offset
+                       + shp[i].sh_size);
+               j = shp[i].sh_link;
+               if (shp[j].sh_offset == 0)
+                       continue;
+               strtab_start = (char*)sstab + shp[j].sh_offset;
+               strtab_end = (char*)sstab + shp[j].sh_offset + shp[j].sh_size;
+               break;
+       }
+
+       if (!symtab_start || !strtab_start)
+               return NULL;
+
+       for (sp = symtab_start; sp < symtab_end; sp++)
+               if (sp->st_name != 0 &&
+                   strcmp(strtab_start + sp->st_name, symname) == 0)
+                       return (void*)(uintptr_t)sp->st_value;
+
+       return NULL;
+}
+
+#endif /* (ELFSIZE == 32 && BOOT_ELF32) || (ELFSIZE == 64 && BOOT_ELF64) */
diff -r 2250bbb035c8 -r d9fdc55c4ea4 sys/lib/libsa/lookup_elf64.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/lib/libsa/lookup_elf64.c      Wed Feb 10 21:54:47 2010 +0000
@@ -0,0 +1,33 @@
+/* $NetBSD: lookup_elf64.c,v 1.1 2010/02/10 21:54:47 martin Exp $ */
+/*-
+ * Copyright (c) 2010 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Martin Husemann.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#define        ELFSIZE 64
+
+#include "lookup_elf32.c"