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534217f7 WL |
1 | /* |
2 | * FreeBSD setup_initial_stack() implementation. | |
3 | * | |
4 | * Copyright (c) 2013-14 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 | ||
9c092804 MA |
20 | #ifndef TARGET_OS_STACK_H |
21 | #define TARGET_OS_STACK_H | |
534217f7 WL |
22 | |
23 | #include <sys/param.h> | |
24 | #include "target_arch_sigtramp.h" | |
25 | #include "qemu/guest-random.h" | |
26 | ||
27 | /* | |
944399ff | 28 | * The initial FreeBSD stack is as follows: |
534217f7 WL |
29 | * (see kern/kern_exec.c exec_copyout_strings() ) |
30 | * | |
31 | * Hi Address -> char **ps_argvstr (struct ps_strings for ps, w, etc.) | |
32 | * unsigned ps_nargvstr | |
33 | * char **ps_envstr | |
34 | * PS_STRINGS -> unsigned ps_nenvstr | |
35 | * | |
36 | * machine dependent sigcode (sv_sigcode of size | |
37 | * sv_szsigcode) | |
38 | * | |
39 | * execpath (absolute image path for rtld) | |
40 | * | |
41 | * SSP Canary (sizeof(long) * 8) | |
42 | * | |
43 | * page sizes array (usually sizeof(u_long) ) | |
44 | * | |
45 | * "destp" -> argv, env strings (up to 262144 bytes) | |
46 | */ | |
47 | static inline int setup_initial_stack(struct bsd_binprm *bprm, | |
48 | abi_ulong *ret_addr, abi_ulong *stringp) | |
49 | { | |
50 | int i; | |
51 | abi_ulong stack_hi_addr; | |
52 | size_t execpath_len, stringspace; | |
53 | abi_ulong destp, argvp, envp, p; | |
54 | struct target_ps_strings ps_strs; | |
55 | char canary[sizeof(abi_long) * 8]; | |
56 | ||
57 | stack_hi_addr = p = target_stkbas + target_stksiz; | |
58 | ||
59 | /* Save some space for ps_strings. */ | |
60 | p -= sizeof(struct target_ps_strings); | |
61 | ||
944399ff | 62 | /* Add machine dependent sigcode. */ |
534217f7 WL |
63 | p -= TARGET_SZSIGCODE; |
64 | if (setup_sigtramp(p, (unsigned)offsetof(struct target_sigframe, sf_uc), | |
65 | TARGET_FREEBSD_NR_sigreturn)) { | |
66 | errno = EFAULT; | |
67 | return -1; | |
68 | } | |
69 | if (bprm->fullpath) { | |
70 | execpath_len = strlen(bprm->fullpath) + 1; | |
71 | p -= roundup(execpath_len, sizeof(abi_ulong)); | |
72 | if (memcpy_to_target(p, bprm->fullpath, execpath_len)) { | |
73 | errno = EFAULT; | |
74 | return -1; | |
75 | } | |
76 | } | |
77 | /* Add canary for SSP. */ | |
78 | qemu_guest_getrandom_nofail(canary, sizeof(canary)); | |
79 | p -= roundup(sizeof(canary), sizeof(abi_ulong)); | |
80 | if (memcpy_to_target(p, canary, sizeof(canary))) { | |
81 | errno = EFAULT; | |
82 | return -1; | |
83 | } | |
84 | /* Add page sizes array. */ | |
85 | p -= sizeof(abi_ulong); | |
86 | if (put_user_ual(TARGET_PAGE_SIZE, p)) { | |
87 | errno = EFAULT; | |
88 | return -1; | |
89 | } | |
90 | /* | |
91 | * Deviate from FreeBSD stack layout: force stack to new page here | |
92 | * so that signal trampoline is not sharing the page with user stack | |
93 | * frames. This is actively harmful in qemu as it marks pages with | |
94 | * code it translated as read-only, which is somewhat problematic | |
95 | * for user trying to use the stack as intended. | |
96 | */ | |
97 | p = rounddown(p, TARGET_PAGE_SIZE); | |
98 | ||
99 | /* Calculate the string space needed */ | |
100 | stringspace = 0; | |
101 | for (i = 0; i < bprm->argc; ++i) { | |
102 | stringspace += strlen(bprm->argv[i]) + 1; | |
103 | } | |
104 | for (i = 0; i < bprm->envc; ++i) { | |
105 | stringspace += strlen(bprm->envp[i]) + 1; | |
106 | } | |
107 | if (stringspace > TARGET_ARG_MAX) { | |
108 | errno = ENOMEM; | |
109 | return -1; | |
110 | } | |
111 | /* Make room for the argv and envp strings */ | |
112 | destp = rounddown(p - stringspace, sizeof(abi_ulong)); | |
113 | p = argvp = destp - (bprm->argc + bprm->envc + 2) * sizeof(abi_ulong); | |
114 | /* Remember the strings pointer */ | |
115 | if (stringp) { | |
116 | *stringp = destp; | |
117 | } | |
118 | /* | |
119 | * Add argv strings. Note that the argv[] vectors are added by | |
120 | * loader_build_argptr() | |
121 | */ | |
122 | /* XXX need to make room for auxargs */ | |
123 | ps_strs.ps_argvstr = tswapl(argvp); | |
124 | ps_strs.ps_nargvstr = tswap32(bprm->argc); | |
125 | for (i = 0; i < bprm->argc; ++i) { | |
126 | size_t len = strlen(bprm->argv[i]) + 1; | |
127 | ||
128 | if (memcpy_to_target(destp, bprm->argv[i], len)) { | |
129 | errno = EFAULT; | |
130 | return -1; | |
131 | } | |
132 | if (put_user_ual(destp, argvp)) { | |
133 | errno = EFAULT; | |
134 | return -1; | |
135 | } | |
136 | argvp += sizeof(abi_ulong); | |
137 | destp += len; | |
138 | } | |
139 | if (put_user_ual(0, argvp)) { | |
140 | errno = EFAULT; | |
141 | return -1; | |
142 | } | |
143 | /* | |
144 | * Add env strings. Note that the envp[] vectors are added by | |
145 | * loader_build_argptr(). | |
146 | */ | |
147 | envp = argvp + sizeof(abi_ulong); | |
148 | ps_strs.ps_envstr = tswapl(envp); | |
149 | ps_strs.ps_nenvstr = tswap32(bprm->envc); | |
150 | for (i = 0; i < bprm->envc; ++i) { | |
151 | size_t len = strlen(bprm->envp[i]) + 1; | |
152 | ||
153 | if (memcpy_to_target(destp, bprm->envp[i], len)) { | |
154 | errno = EFAULT; | |
155 | return -1; | |
156 | } | |
157 | if (put_user_ual(destp, envp)) { | |
158 | errno = EFAULT; | |
159 | return -1; | |
160 | } | |
161 | envp += sizeof(abi_ulong); | |
162 | destp += len; | |
163 | } | |
164 | if (put_user_ual(0, envp)) { | |
165 | errno = EFAULT; | |
166 | return -1; | |
167 | } | |
168 | if (memcpy_to_target(stack_hi_addr - sizeof(ps_strs), &ps_strs, | |
169 | sizeof(ps_strs))) { | |
170 | errno = EFAULT; | |
171 | return -1; | |
172 | } | |
173 | ||
174 | if (ret_addr) { | |
175 | *ret_addr = p; | |
176 | } | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
9c092804 | 181 | #endif /* TARGET_OS_STACK_H */ |