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kobj_rename.c revision 1.1.6.2 
      1 /*	$NetBSD: kobj_rename.c,v 1.1.6.2 2010/08/11 22:55:06 yamt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2010 Antti Kantee.  All Rights Reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  * SUCH DAMAGE.
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 __KERNEL_RCSID(0, "$NetBSD: kobj_rename.c,v 1.1.6.2 2010/08/11 22:55:06 yamt Exp $");
     30 
     31 #define ELFSIZE ARCH_ELFSIZE
     32 
     33 #include <sys/param.h>
     34 #include <sys/exec_elf.h>
     35 #include <sys/kmem.h>
     36 #include <sys/kobj.h>
     37 #include <sys/systm.h>
     38 
     39 /*
     40  * Mangle symbols into rump kernel namespace.  This means
     41  * putting "rumpns" in front of select symbols.
     42  * See src/sys/rump/Makefile.rump for more details on the rump kernel
     43  * namespace.
     44  */
     45 const char *norentab[] = {
     46 	"RUMP",
     47 	"rump",
     48 	"__",
     49 	"_GLOBAL_OFFSET_TABLE",
     50 };
     51 static int
     52 norename(const char *name)
     53 {
     54 	unsigned i;
     55 
     56 	for (i = 0; i < __arraycount(norentab); i++) {
     57 		if (strncmp(norentab[i], name, strlen(norentab[i])) == 0)
     58 			return 1;
     59 	}
     60 	return 0;
     61 }
     62 
     63 #define RUMPNS "rumpns_"
     64 int
     65 kobj_renamespace(Elf_Sym *symtab, size_t symcount,
     66 	char **strtab, size_t *strtabsz)
     67 {
     68 	Elf_Sym *sym;
     69 	char *worktab, *newtab;
     70 	size_t worktabsz, worktabidx;
     71 	unsigned i;
     72 	const size_t prefixlen = strlen(RUMPNS);
     73 
     74 #ifndef _RUMP_NATIVE_ABI
     75 	static int warned;
     76 
     77 	if (!warned) {
     78 		printf("warning: kernel ABI not supported on this arch\n");
     79 		warned = 1;
     80 	}
     81 #endif
     82 
     83 	/* allocate space for worst-case stringtab */
     84 	worktabsz = *strtabsz + symcount * prefixlen;
     85 	worktab = kmem_alloc(worktabsz, KM_SLEEP);
     86 
     87 	/* now, adjust stringtab into temporary space */
     88 #define WORKTABP (worktab + worktabidx)
     89 	for (i = 0, worktabidx = 0; i < symcount; i++) {
     90 		const char *fromname;
     91 
     92 		sym = &symtab[i];
     93 		if (sym->st_name == 0) {
     94 			continue;
     95 		}
     96 
     97 		fromname = *strtab + sym->st_name;
     98 		sym->st_name = worktabidx;
     99 
    100 		if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL ||
    101 		    norename(fromname)) {
    102 			strcpy(WORKTABP, fromname);
    103 			worktabidx += strlen(fromname) + 1;
    104 		} else {
    105 			strcpy(WORKTABP, RUMPNS);
    106 			worktabidx += prefixlen;
    107 			strcpy(WORKTABP, fromname);
    108 			worktabidx += strlen(fromname) + 1;
    109 		}
    110 		KASSERT(worktabidx <= worktabsz);
    111 	}
    112 #undef WORKTABP
    113 
    114 	/*
    115 	 * Finally, free old strtab, allocate new one, and copy contents.
    116 	 */
    117 	kmem_free(*strtab, *strtabsz);
    118 	*strtab = NULL; /* marvin the paradroid 999 */
    119 	newtab = kmem_alloc(worktabidx, KM_SLEEP);
    120 	memcpy(newtab, worktab, worktabidx);
    121 
    122 	kmem_free(worktab, worktabsz);
    123 
    124 	*strtab = newtab;
    125 	*strtabsz = worktabidx;
    126 
    127 	return 0;
    128 }
    129