2 * Hosted file support for semihosting syscalls.
4 * Copyright (c) 2005, 2007 CodeSourcery.
5 * Copyright (c) 2019 Linaro
6 * Copyright © 2020 by Keith Packard <keithp@keithp.com>
8 * SPDX-License-Identifier: GPL-2.0-or-later
11 #include "qemu/osdep.h"
12 #include "exec/gdbstub.h"
13 #include "semihosting/semihost.h"
14 #include "semihosting/guestfd.h"
15 #ifdef CONFIG_USER_ONLY
18 #include "semihosting/softmmu-uaccess.h"
19 #include CONFIG_DEVICES
22 static GArray *guestfd_array;
24 #ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING
25 GuestFD console_in_gf;
26 GuestFD console_out_gf;
29 void qemu_semihosting_guestfd_init(void)
31 /* New entries zero-initialized, i.e. type GuestFDUnused */
32 guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD));
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;
42 console_in_gf.type = GuestFDConsole;
43 console_out_gf.type = GuestFDConsole;
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;
57 associate_guestfd(0, 0);
58 associate_guestfd(1, 1);
59 associate_guestfd(2, 2);
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.
70 int alloc_guestfd(void)
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);
78 if (gf->type == GuestFDUnused) {
83 /* All elements already in use: expand the array */
84 g_array_set_size(guestfd_array, i + 1);
88 static void do_dealloc_guestfd(GuestFD *gf)
90 gf->type = GuestFDUnused;
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.
98 static GuestFD *do_get_guestfd(int guestfd)
100 if (guestfd < 0 || guestfd >= guestfd_array->len) {
104 return &g_array_index(guestfd_array, GuestFD, guestfd);
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
112 * Note: calling alloc_guestfd() or dealloc_guestfd() will
113 * invalidate any GuestFD* obtained by calling this function.
115 GuestFD *get_guestfd(int guestfd)
117 GuestFD *gf = do_get_guestfd(guestfd);
119 if (!gf || gf->type == GuestFDUnused) {
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.
130 void associate_guestfd(int guestfd, int hostfd)
132 GuestFD *gf = do_get_guestfd(guestfd);
135 gf->type = use_gdb_syscalls() ? GuestFDGDB : GuestFDHost;
139 void staticfile_guestfd(int guestfd, const uint8_t *data, size_t len)
141 GuestFD *gf = do_get_guestfd(guestfd);
144 gf->type = GuestFDStatic;
145 gf->staticfile.data = data;
146 gf->staticfile.len = len;
147 gf->staticfile.off = 0;
151 * Deallocate the specified guest file descriptor. This doesn't
152 * close the host fd, it merely undoes the work of alloc_fd().
154 void dealloc_guestfd(int guestfd)
156 GuestFD *gf = do_get_guestfd(guestfd);
159 do_dealloc_guestfd(gf);