1 /* $OpenBSD: boot.c,v 1.18 2019/10/20 03:44:49 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB 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 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR 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 29 /* 30 * IMPORTANT: any functions below are NOT protected by SSP. Please 31 * do not add anything except what is required to reach GOT with 32 * an adjustment. 33 */ 34 35 #define _DYN_LOADER 36 37 #include <sys/exec_elf.h> 38 39 #include "syscall.h" 40 #include "archdep.h" 41 42 #include "../../lib/csu/os-note-elf.h" 43 44 #if RELOC_TAG == DT_RELA 45 typedef Elf_RelA RELOC_TYPE; 46 # define RELOCATE_RELATIVE(w, r, b) *(w) = (r)->r_addend + (b) 47 #elif RELOC_TAG == DT_REL 48 typedef Elf_Rel RELOC_TYPE; 49 # define RELOCATE_RELATIVE(w, r, b) *(w) += (b) 50 #else 51 # error "unknown RELOC_TAG" 52 #endif 53 54 /* 55 * Local decls. 56 */ 57 void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot; 58 59 void 60 _dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp) 61 { 62 AuxInfo *auxstack; 63 long *stack; 64 int n, argc; 65 char **argv, **envp; 66 long loff; 67 RELOC_TYPE *dt_reloc; /* DT_RELA or DT_REL */ 68 Elf_Word dt_relocsz; /* DT_RELASZ or DT_RELSZ */ 69 RELOC_TYPE *rend; 70 71 /* 72 * Scan argument and environment vectors. Find dynamic 73 * data vector put after them. 74 */ 75 stack = (long *)sp; 76 argc = *stack++; 77 argv = (char **)stack; 78 envp = &argv[argc + 1]; 79 stack = (long *)envp; 80 while (*stack++ != 0L) 81 ; 82 83 /* 84 * Zero out dl_data. 85 */ 86 for (n = 0; n <= AUX_entry; n++) 87 dl_data[n] = 0; 88 89 /* 90 * Dig out auxiliary data set up by exec call. Move all known 91 * tags to an indexed local table for easy access. 92 */ 93 for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null; 94 auxstack++) { 95 if (auxstack->au_id > AUX_entry) 96 continue; 97 dl_data[auxstack->au_id] = auxstack->au_v; 98 } 99 loff = dl_data[AUX_base]; /* XXX assumes ld.so is linked at 0x0 */ 100 101 /* 102 * Scan the DYNAMIC section for the loader for the two items we need 103 */ 104 dt_reloc = NULL; 105 dt_relocsz = 0; 106 while (dynp->d_tag != DT_NULL) { 107 if (dynp->d_tag == RELOC_TAG) /* DT_{RELA,REL} */ 108 dt_reloc = (void *)(dynp->d_un.d_ptr + loff); 109 else if (dynp->d_tag == RELOC_TAG+1) /* DT_{RELA,REL}SZ */ 110 dt_relocsz = dynp->d_un.d_val; 111 dynp++; 112 } 113 114 rend = (RELOC_TYPE *)((char *)dt_reloc + dt_relocsz); 115 for (; dt_reloc < rend; dt_reloc++) { 116 Elf_Addr *ra; 117 118 ra = (Elf_Addr *)(dt_reloc->r_offset + loff); 119 RELOCATE_RELATIVE(ra, dt_reloc, loff); 120 } 121 } 122