1 /*
2  *  openbsd ELF definitions
3  *
4  *  Copyright (c) 2013 Stacey D. Son
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #ifndef TARGET_OS_ELF_H
21 #define TARGET_OS_ELF_H
22 
23 #include "target_arch_elf.h"
24 #include "elf.h"
25 
26 /* this flag is uneffective under linux too, should be deleted */
27 #ifndef MAP_DENYWRITE
28 #define MAP_DENYWRITE 0
29 #endif
30 
31 /* should probably go in elf.h */
32 #ifndef ELIBBAD
33 #define ELIBBAD 80
34 #endif
35 
36 #ifndef ELF_PLATFORM
37 #define ELF_PLATFORM (NULL)
38 #endif
39 
40 #ifndef ELF_HWCAP
41 #define ELF_HWCAP 0
42 #endif
43 
44 #ifdef TARGET_ABI32
45 #undef ELF_CLASS
46 #define ELF_CLASS ELFCLASS32
47 #undef bswaptls
48 #define bswaptls(ptr) bswap32s(ptr)
49 #endif
50 
51 /* max code+data+bss space allocated to elf interpreter */
52 #define INTERP_MAP_SIZE (32 * 1024 * 1024)
53 
54 /* max code+data+bss+brk space allocated to ET_DYN executables */
55 #define ET_DYN_MAP_SIZE (128 * 1024 * 1024)
56 
57 /* Necessary parameters */
58 #define TARGET_ELF_EXEC_PAGESIZE TARGET_PAGE_SIZE
59 #define TARGET_ELF_PAGESTART(_v) ((_v) & \
60         ~(unsigned long)(TARGET_ELF_EXEC_PAGESIZE - 1))
61 #define TARGET_ELF_PAGEOFFSET(_v) ((_v) & (TARGET_ELF_EXEC_PAGESIZE - 1))
62 
63 #define DLINFO_ITEMS 12
64 
65 static abi_ulong target_create_elf_tables(abi_ulong p, int argc, int envc,
66                                           abi_ulong stringp,
67                                           struct elfhdr *exec,
68                                           abi_ulong load_addr,
69                                           abi_ulong load_bias,
70                                           abi_ulong interp_load_addr,
71                                           struct image_info *info)
72 {
73         abi_ulong sp;
74         int size;
75         abi_ulong u_platform;
76         const char *k_platform;
77         const int n = sizeof(elf_addr_t);
78 
79         sp = p;
80         u_platform = 0;
81         k_platform = ELF_PLATFORM;
82         if (k_platform) {
83             size_t len = strlen(k_platform) + 1;
84             sp -= (len + n - 1) & ~(n - 1);
85             u_platform = sp;
86             /* FIXME - check return value of memcpy_to_target() for failure */
87             memcpy_to_target(sp, k_platform, len);
88         }
89         /*
90          * Force 16 byte _final_ alignment here for generality.
91          */
92         sp = sp & ~(abi_ulong)15;
93         size = (DLINFO_ITEMS + 1) * 2;
94         if (k_platform) {
95             size += 2;
96         }
97 #ifdef DLINFO_ARCH_ITEMS
98         size += DLINFO_ARCH_ITEMS * 2;
99 #endif
100         size += envc + argc + 2;
101         size += 1;                        /* argc itself */
102         size *= n;
103         if (size & 15) {
104             sp -= 16 - (size & 15);
105         }
106 
107         /*
108          * OpenBSD defines elf_addr_t as Elf32_Off / Elf64_Off
109          */
110 #define NEW_AUX_ENT(id, val) do {               \
111             sp -= n; put_user_ual(val, sp);     \
112             sp -= n; put_user_ual(id, sp);      \
113           } while (0)
114 
115         NEW_AUX_ENT(AT_NULL, 0);
116 
117         /* There must be exactly DLINFO_ITEMS entries here.  */
118         NEW_AUX_ENT(AT_PHDR, (abi_ulong)(load_addr + exec->e_phoff));
119         NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof(struct elf_phdr)));
120         NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));
121         NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE));
122         NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_load_addr));
123         NEW_AUX_ENT(AT_FLAGS, (abi_ulong)0);
124         NEW_AUX_ENT(AT_ENTRY, load_bias + exec->e_entry);
125         NEW_AUX_ENT(AT_UID, (abi_ulong)getuid());
126         NEW_AUX_ENT(AT_EUID, (abi_ulong)geteuid());
127         NEW_AUX_ENT(AT_GID, (abi_ulong)getgid());
128         NEW_AUX_ENT(AT_EGID, (abi_ulong)getegid());
129         NEW_AUX_ENT(AT_HWCAP, (abi_ulong)ELF_HWCAP);
130         NEW_AUX_ENT(AT_CLKTCK, (abi_ulong)sysconf(_SC_CLK_TCK));
131         if (k_platform) {
132             NEW_AUX_ENT(AT_PLATFORM, u_platform);
133         }
134 #ifdef ARCH_DLINFO
135         /*
136          * ARCH_DLINFO must come last so platform specific code can enforce
137          * special alignment requirements on the AUXV if necessary (eg. PPC).
138          */
139         ARCH_DLINFO;
140 #endif
141 #undef NEW_AUX_ENT
142 
143         sp = loader_build_argptr(envc, argc, sp, stringp);
144         return sp;
145 }
146 
147 #endif /* TARGET_OS_ELF_H */
148