1 | /* Initial program startup for running under the GNU Hurd. |
2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <errno.h> |
20 | #include <stdlib.h> |
21 | #include <stdio.h> |
22 | #include <string.h> |
23 | #include <hurd.h> |
24 | #include <hurd/exec_startup.h> |
25 | #include <sysdep.h> |
26 | #include <unistd.h> |
27 | #include <elf.h> |
28 | #include <set-hooks.h> |
29 | #include "hurdstartup.h" |
30 | #include <argz.h> |
31 | |
32 | mach_port_t *_hurd_init_dtable; |
33 | mach_msg_type_number_t _hurd_init_dtablesize; |
34 | |
35 | extern void __mach_init (void); |
36 | |
37 | /* Entry point. This is the first thing in the text segment. |
38 | |
39 | The exec server started the initial thread in our task with this spot the |
40 | PC, and a stack that is presumably big enough. We do basic Mach |
41 | initialization so mig-generated stubs work, and then do an exec_startup |
42 | RPC on our bootstrap port, to which the exec server responds with the |
43 | information passed in the exec call, as well as our original bootstrap |
44 | port, and the base address and size of the preallocated stack. */ |
45 | |
46 | |
47 | void |
48 | _hurd_startup (void **argptr, void (*main) (intptr_t *data)) |
49 | { |
50 | error_t err; |
51 | mach_port_t in_bootstrap; |
52 | char *args, *env; |
53 | mach_msg_type_number_t argslen, envlen; |
54 | struct hurd_startup_data data; |
55 | char **argv, **envp; |
56 | int argc, envc; |
57 | intptr_t *argcptr; |
58 | vm_address_t addr; |
59 | |
60 | /* Attempt to map page zero redzoned before we receive any RPC |
61 | data that might get allocated there. We can ignore errors. */ |
62 | addr = 0; |
63 | __vm_map (__mach_task_self (), |
64 | &addr, __vm_page_size, 0, 0, MACH_PORT_NULL, 0, 1, |
65 | VM_PROT_NONE, VM_PROT_NONE, VM_INHERIT_COPY); |
66 | |
67 | if (err = __task_get_special_port (__mach_task_self (), TASK_BOOTSTRAP_PORT, |
68 | &in_bootstrap)) |
69 | LOSE; |
70 | |
71 | if (in_bootstrap != MACH_PORT_NULL) |
72 | { |
73 | /* Call the exec server on our bootstrap port and |
74 | get all our standard information from it. */ |
75 | |
76 | argslen = envlen = 0; |
77 | data.dtablesize = data.portarraysize = data.intarraysize = 0; |
78 | |
79 | err = __exec_startup_get_info (in_bootstrap, |
80 | &data.user_entry, |
81 | &data.phdr, &data.phdrsz, |
82 | &data.stack_base, &data.stack_size, |
83 | &data.flags, |
84 | &args, &argslen, |
85 | &env, &envlen, |
86 | &data.dtable, &data.dtablesize, |
87 | &data.portarray, &data.portarraysize, |
88 | &data.intarray, &data.intarraysize); |
89 | __mach_port_deallocate (__mach_task_self (), in_bootstrap); |
90 | } |
91 | |
92 | if (err || in_bootstrap == MACH_PORT_NULL || (data.flags & EXEC_STACK_ARGS)) |
93 | { |
94 | /* Either we have no bootstrap port, or the RPC to the exec server |
95 | failed, or whoever started us up passed the flag saying args are |
96 | on the stack. Try to snarf the args in the canonical Mach way. |
97 | Hopefully either they will be on the stack as expected, or the |
98 | stack will be zeros so we don't crash. */ |
99 | |
100 | argcptr = (intptr_t *) argptr; |
101 | argc = argcptr[0]; |
102 | argv = (char **) &argcptr[1]; |
103 | envp = &argv[argc + 1]; |
104 | envc = 0; |
105 | while (envp[envc]) |
106 | ++envc; |
107 | } |
108 | else |
109 | { |
110 | /* Turn the block of null-separated strings we were passed for the |
111 | arguments and environment into vectors of pointers to strings. */ |
112 | |
113 | /* Count up the arguments so we can allocate ARGV. */ |
114 | argc = __argz_count (args, argslen); |
115 | /* Count up the environment variables so we can allocate ENVP. */ |
116 | envc = __argz_count (env, envlen); |
117 | |
118 | /* There were some arguments. Allocate space for the vectors of |
119 | pointers and fill them in. We allocate the space for the |
120 | environment pointers immediately after the argv pointers because |
121 | the ELF ABI will expect it. */ |
122 | argcptr = __alloca (sizeof (intptr_t) |
123 | + (argc + 1 + envc + 1) * sizeof (char *) |
124 | + sizeof (struct hurd_startup_data)); |
125 | *argcptr = argc; |
126 | argv = (void *) (argcptr + 1); |
127 | __argz_extract (args, argslen, argv); |
128 | |
129 | /* There was some environment. */ |
130 | envp = &argv[argc + 1]; |
131 | __argz_extract (env, envlen, envp); |
132 | } |
133 | |
134 | if (err || in_bootstrap == MACH_PORT_NULL) |
135 | { |
136 | /* Either we have no bootstrap port, or the RPC to the exec server |
137 | failed. Set all our other variables to have empty information. */ |
138 | |
139 | data.flags = 0; |
140 | args = env = NULL; |
141 | argslen = envlen = 0; |
142 | data.dtable = NULL; |
143 | data.dtablesize = 0; |
144 | data.portarray = NULL; |
145 | data.portarraysize = 0; |
146 | data.intarray = NULL; |
147 | data.intarraysize = 0; |
148 | } |
149 | else if ((void *) &envp[envc + 1] == argv[0]) |
150 | { |
151 | /* The arguments arrived on the stack from the kernel, but our |
152 | protocol requires some space after them for a `struct |
153 | hurd_startup_data'. Move them. */ |
154 | struct |
155 | { |
156 | intptr_t count; |
157 | char *argv[argc + 1]; |
158 | char *envp[envc + 1]; |
159 | struct hurd_startup_data data; |
160 | } *args = alloca (sizeof *args); |
161 | if ((void *) &args[1] == (void *) argcptr) |
162 | args = alloca (-((char *) &args->data - (char *) args)); |
163 | memmove (dest: args, src: argcptr, n: (char *) &args->data - (char *) args); |
164 | argcptr = (void *) args; |
165 | argv = args->argv; |
166 | envp = args->envp; |
167 | } |
168 | |
169 | { |
170 | struct hurd_startup_data *d = (void *) &envp[envc + 1]; |
171 | |
172 | if ((void *) d != argv[0]) |
173 | { |
174 | *d = data; |
175 | _hurd_init_dtable = d->dtable; |
176 | _hurd_init_dtablesize = d->dtablesize; |
177 | } |
178 | |
179 | (*main) (argcptr); |
180 | } |
181 | |
182 | /* Should never get here. */ |
183 | LOSE; |
184 | abort (); |
185 | } |
186 | |