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1 | /* | |
2 | * Hosted file support for semihosting syscalls. | |
3 | * | |
4 | * Copyright (c) 2005, 2007 CodeSourcery. | |
5 | * Copyright (c) 2019 Linaro | |
6 | * Copyright © 2020 by Keith Packard <keithp@keithp.com> | |
7 | * | |
8 | * SPDX-License-Identifier: GPL-2.0-or-later | |
9 | */ | |
10 | ||
11 | #include "qemu/osdep.h" | |
12 | #include "gdbstub/syscalls.h" | |
13 | #include "semihosting/semihost.h" | |
14 | #include "semihosting/guestfd.h" | |
15 | #ifdef CONFIG_USER_ONLY | |
16 | #include "qemu.h" | |
17 | #else | |
18 | #include "semihosting/softmmu-uaccess.h" | |
19 | #include CONFIG_DEVICES | |
20 | #endif | |
21 | ||
22 | static GArray *guestfd_array; | |
23 | ||
24 | #ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING | |
25 | GuestFD console_in_gf; | |
26 | GuestFD console_out_gf; | |
27 | #endif | |
28 | ||
29 | void qemu_semihosting_guestfd_init(void) | |
30 | { | |
31 | /* New entries zero-initialized, i.e. type GuestFDUnused */ | |
32 | guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD)); | |
33 | ||
34 | #ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING | |
35 | /* For ARM-compat, the console is in a separate namespace. */ | |
36 | if (use_gdb_syscalls()) { | |
37 | console_in_gf.type = GuestFDGDB; | |
38 | console_in_gf.hostfd = 0; | |
39 | console_out_gf.type = GuestFDGDB; | |
40 | console_out_gf.hostfd = 2; | |
41 | } else { | |
42 | console_in_gf.type = GuestFDConsole; | |
43 | console_out_gf.type = GuestFDConsole; | |
44 | } | |
45 | #else | |
46 | /* Otherwise, the stdio file descriptors apply. */ | |
47 | guestfd_array = g_array_set_size(guestfd_array, 3); | |
48 | #ifndef CONFIG_USER_ONLY | |
49 | if (!use_gdb_syscalls()) { | |
50 | GuestFD *gf = &g_array_index(guestfd_array, GuestFD, 0); | |
51 | gf[0].type = GuestFDConsole; | |
52 | gf[1].type = GuestFDConsole; | |
53 | gf[2].type = GuestFDConsole; | |
54 | return; | |
55 | } | |
56 | #endif | |
57 | associate_guestfd(0, 0); | |
58 | associate_guestfd(1, 1); | |
59 | associate_guestfd(2, 2); | |
60 | #endif | |
61 | } | |
62 | ||
63 | /* | |
64 | * Allocate a new guest file descriptor and return it; if we | |
65 | * couldn't allocate a new fd then return -1. | |
66 | * This is a fairly simplistic implementation because we don't | |
67 | * expect that most semihosting guest programs will make very | |
68 | * heavy use of opening and closing fds. | |
69 | */ | |
70 | int alloc_guestfd(void) | |
71 | { | |
72 | guint i; | |
73 | ||
74 | /* SYS_OPEN should return nonzero handle on success. Start guestfd from 1 */ | |
75 | for (i = 1; i < guestfd_array->len; i++) { | |
76 | GuestFD *gf = &g_array_index(guestfd_array, GuestFD, i); | |
77 | ||
78 | if (gf->type == GuestFDUnused) { | |
79 | return i; | |
80 | } | |
81 | } | |
82 | ||
83 | /* All elements already in use: expand the array */ | |
84 | g_array_set_size(guestfd_array, i + 1); | |
85 | return i; | |
86 | } | |
87 | ||
88 | static void do_dealloc_guestfd(GuestFD *gf) | |
89 | { | |
90 | gf->type = GuestFDUnused; | |
91 | } | |
92 | ||
93 | /* | |
94 | * Look up the guestfd in the data structure; return NULL | |
95 | * for out of bounds, but don't check whether the slot is unused. | |
96 | * This is used internally by the other guestfd functions. | |
97 | */ | |
98 | static GuestFD *do_get_guestfd(int guestfd) | |
99 | { | |
100 | if (guestfd < 0 || guestfd >= guestfd_array->len) { | |
101 | return NULL; | |
102 | } | |
103 | ||
104 | return &g_array_index(guestfd_array, GuestFD, guestfd); | |
105 | } | |
106 | ||
107 | /* | |
108 | * Given a guest file descriptor, get the associated struct. | |
109 | * If the fd is not valid, return NULL. This is the function | |
110 | * used by the various semihosting calls to validate a handle | |
111 | * from the guest. | |
112 | * Note: calling alloc_guestfd() or dealloc_guestfd() will | |
113 | * invalidate any GuestFD* obtained by calling this function. | |
114 | */ | |
115 | GuestFD *get_guestfd(int guestfd) | |
116 | { | |
117 | GuestFD *gf = do_get_guestfd(guestfd); | |
118 | ||
119 | if (!gf || gf->type == GuestFDUnused) { | |
120 | return NULL; | |
121 | } | |
122 | return gf; | |
123 | } | |
124 | ||
125 | /* | |
126 | * Associate the specified guest fd (which must have been | |
127 | * allocated via alloc_fd() and not previously used) with | |
128 | * the specified host/gdb fd. | |
129 | */ | |
130 | void associate_guestfd(int guestfd, int hostfd) | |
131 | { | |
132 | GuestFD *gf = do_get_guestfd(guestfd); | |
133 | ||
134 | assert(gf); | |
135 | gf->type = use_gdb_syscalls() ? GuestFDGDB : GuestFDHost; | |
136 | gf->hostfd = hostfd; | |
137 | } | |
138 | ||
139 | void staticfile_guestfd(int guestfd, const uint8_t *data, size_t len) | |
140 | { | |
141 | GuestFD *gf = do_get_guestfd(guestfd); | |
142 | ||
143 | assert(gf); | |
144 | gf->type = GuestFDStatic; | |
145 | gf->staticfile.data = data; | |
146 | gf->staticfile.len = len; | |
147 | gf->staticfile.off = 0; | |
148 | } | |
149 | ||
150 | /* | |
151 | * Deallocate the specified guest file descriptor. This doesn't | |
152 | * close the host fd, it merely undoes the work of alloc_fd(). | |
153 | */ | |
154 | void dealloc_guestfd(int guestfd) | |
155 | { | |
156 | GuestFD *gf = do_get_guestfd(guestfd); | |
157 | ||
158 | assert(gf); | |
159 | do_dealloc_guestfd(gf); | |
160 | } |