1 /* $OpenBSD: boot_md.c,v 1.3 2019/11/10 22:21:54 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 #include "stdlib.h" 42 43 #include "../../lib/csu/os-note-elf.h" 44 45 #if RELOC_TAG == DT_RELA 46 typedef Elf_RelA RELOC_TYPE; 47 #elif RELOC_TAG == DT_REL 48 typedef Elf_Rel RELOC_TYPE; 49 #else 50 # error "unknown RELOC_TAG" 51 #endif 52 53 /* The set of dynamic tags that we're interested in for bootstrapping */ 54 struct boot_dyn { 55 RELOC_TYPE *dt_reloc; /* DT_RELA or DT_REL */ 56 Elf_Addr dt_relocsz; /* DT_RELASZ or DT_RELSZ */ 57 Elf_Addr *dt_pltgot; 58 const Elf_Sym *dt_symtab; 59 #if DT_PROCNUM > 0 60 u_long dt_proc[DT_PROCNUM]; 61 #endif 62 }; 63 64 /* 65 * Local decls. 66 */ 67 void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot; 68 69 void 70 _dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp) 71 { 72 struct boot_dyn dynld; /* Resolver data for the loader */ 73 AuxInfo *auxstack; 74 long *stack; 75 int n, argc; 76 char **argv, **envp; 77 long loff; 78 RELOC_TYPE *rp, *rend; 79 80 /* 81 * Scan argument and environment vectors. Find dynamic 82 * data vector put after them. 83 */ 84 stack = (long *)sp; 85 argc = *stack++; 86 argv = (char **)stack; 87 envp = &argv[argc + 1]; 88 stack = (long *)envp; 89 while (*stack++ != 0L) 90 ; 91 92 /* 93 * Zero out dl_data. 94 */ 95 for (n = 0; n <= AUX_entry; n++) 96 dl_data[n] = 0; 97 98 /* 99 * Dig out auxiliary data set up by exec call. Move all known 100 * tags to an indexed local table for easy access. 101 */ 102 for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null; 103 auxstack++) { 104 if (auxstack->au_id > AUX_entry) 105 continue; 106 dl_data[auxstack->au_id] = auxstack->au_v; 107 } 108 loff = dl_data[AUX_base]; /* XXX assumes ld.so is linked at 0x0 */ 109 110 /* 111 * We need to do 'selfreloc' in case the code weren't 112 * loaded at the address it was linked to. 113 * 114 * Scan the DYNAMIC section for the loader. 115 * Cache the data for easier access. 116 */ 117 _dl_memset(&dynld, 0, sizeof(dynld)); 118 while (dynp->d_tag != DT_NULL) { 119 /* first the tags that are pointers to be relocated */ 120 if (dynp->d_tag == DT_PLTGOT) 121 dynld.dt_pltgot = (void *)(dynp->d_un.d_ptr + loff); 122 else if (dynp->d_tag == DT_SYMTAB) 123 dynld.dt_symtab = (void *)(dynp->d_un.d_ptr + loff); 124 else if (dynp->d_tag == RELOC_TAG) /* DT_{RELA,REL} */ 125 dynld.dt_reloc = (void *)(dynp->d_un.d_ptr + loff); 126 127 /* Now for the tags that are just sizes or counts */ 128 else if (dynp->d_tag == RELOC_TAG+1) /* DT_{RELA,REL}SZ */ 129 dynld.dt_relocsz = dynp->d_un.d_val; 130 #if DT_PROCNUM > 0 131 else if (dynp->d_tag >= DT_LOPROC && 132 dynp->d_tag < DT_LOPROC + DT_PROCNUM) 133 dynld.dt_proc[dynp->d_tag - DT_LOPROC] = 134 dynp->d_un.d_val; 135 #endif /* DT_PROCNUM */ 136 dynp++; 137 } 138 139 rp = dynld.dt_reloc; 140 rend = (RELOC_TYPE *)((char *)rp + dynld.dt_relocsz); 141 for (; rp < rend; rp++) { 142 if (ELF_R_TYPE(rp->r_info) != R_MIPS_NONE) { 143 Elf_Addr *ra = (Elf_Addr *)(rp->r_offset + loff); 144 145 *ra += loff; 146 } 147 } 148 149 RELOC_GOT(&dynld, loff); 150 } 151