1 files changed, 160 insertions, 0 deletions
diff --git a/semihosting/guestfd.c b/semihosting/guestfd.c
new file mode 100644
index 0000000000..b05c52f26f
--- /dev/null
+++ b/semihosting/guestfd.c
@@ -0,0 +1,160 @@
+/*
+ * Hosted file support for semihosting syscalls.
+ *
+ * Copyright (c) 2005, 2007 CodeSourcery.
+ * Copyright (c) 2019 Linaro
+ * Copyright © 2020 by Keith Packard <keithp@keithp.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "exec/gdbstub.h"
+#include "semihosting/semihost.h"
+#include "semihosting/guestfd.h"
+#ifdef CONFIG_USER_ONLY
+#include "qemu.h"
+#else
+#include "semihosting/softmmu-uaccess.h"
+#include CONFIG_DEVICES
+#endif
+
+static GArray *guestfd_array;
+
+#ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING
+GuestFD console_in_gf;
+GuestFD console_out_gf;
+#endif
+
+void qemu_semihosting_guestfd_init(void)
+{
+    /* New entries zero-initialized, i.e. type GuestFDUnused */
+    guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD));
+
+#ifdef CONFIG_ARM_COMPATIBLE_SEMIHOSTING
+    /* For ARM-compat, the console is in a separate namespace. */
+    if (use_gdb_syscalls()) {
+        console_in_gf.type = GuestFDGDB;
+        console_in_gf.hostfd = 0;
+        console_out_gf.type = GuestFDGDB;
+        console_out_gf.hostfd = 2;
+    } else {
+        console_in_gf.type = GuestFDConsole;
+        console_out_gf.type = GuestFDConsole;
+    }
+#else
+    /* Otherwise, the stdio file descriptors apply. */
+    guestfd_array = g_array_set_size(guestfd_array, 3);
+#ifndef CONFIG_USER_ONLY
+    if (!use_gdb_syscalls()) {
+        GuestFD *gf = &g_array_index(guestfd_array, GuestFD, 0);
+        gf[0].type = GuestFDConsole;
+        gf[1].type = GuestFDConsole;
+        gf[2].type = GuestFDConsole;
+        return;
+    }
+#endif
+    associate_guestfd(0, 0);
+    associate_guestfd(1, 1);
+    associate_guestfd(2, 2);
+#endif
+}
+
+/*
+ * Allocate a new guest file descriptor and return it; if we
+ * couldn't allocate a new fd then return -1.
+ * This is a fairly simplistic implementation because we don't
+ * expect that most semihosting guest programs will make very
+ * heavy use of opening and closing fds.
+ */
+int alloc_guestfd(void)
+{
+    guint i;
+
+    /* SYS_OPEN should return nonzero handle on success. Start guestfd from 1 */
+    for (i = 1; i < guestfd_array->len; i++) {
+        GuestFD *gf = &g_array_index(guestfd_array, GuestFD, i);
+
+        if (gf->type == GuestFDUnused) {
+            return i;
+        }
+    }
+
+    /* All elements already in use: expand the array */
+    g_array_set_size(guestfd_array, i + 1);
+    return i;
+}
+
+static void do_dealloc_guestfd(GuestFD *gf)
+{
+    gf->type = GuestFDUnused;
+}
+
+/*
+ * Look up the guestfd in the data structure; return NULL
+ * for out of bounds, but don't check whether the slot is unused.
+ * This is used internally by the other guestfd functions.
+ */
+static GuestFD *do_get_guestfd(int guestfd)
+{
+    if (guestfd < 0 || guestfd >= guestfd_array->len) {
+        return NULL;
+    }
+
+    return &g_array_index(guestfd_array, GuestFD, guestfd);
+}
+
+/*
+ * Given a guest file descriptor, get the associated struct.
+ * If the fd is not valid, return NULL. This is the function
+ * used by the various semihosting calls to validate a handle
+ * from the guest.
+ * Note: calling alloc_guestfd() or dealloc_guestfd() will
+ * invalidate any GuestFD* obtained by calling this function.
+ */
+GuestFD *get_guestfd(int guestfd)
+{
+    GuestFD *gf = do_get_guestfd(guestfd);
+
+    if (!gf || gf->type == GuestFDUnused) {
+        return NULL;
+    }
+    return gf;
+}
+
+/*
+ * Associate the specified guest fd (which must have been
+ * allocated via alloc_fd() and not previously used) with
+ * the specified host/gdb fd.
+ */
+void associate_guestfd(int guestfd, int hostfd)
+{
+    GuestFD *gf = do_get_guestfd(guestfd);
+
+    assert(gf);
+    gf->type = use_gdb_syscalls() ? GuestFDGDB : GuestFDHost;
+    gf->hostfd = hostfd;
+}
+
+void staticfile_guestfd(int guestfd, const uint8_t *data, size_t len)
+{
+    GuestFD *gf = do_get_guestfd(guestfd);
+
+    assert(gf);
+    gf->type = GuestFDStatic;
+    gf->staticfile.data = data;
+    gf->staticfile.len = len;
+    gf->staticfile.off = 0;
+}
+
+/*
+ * Deallocate the specified guest file descriptor. This doesn't
+ * close the host fd, it merely undoes the work of alloc_fd().
+ */
+void dealloc_guestfd(int guestfd)
+{
+    GuestFD *gf = do_get_guestfd(guestfd);
+
+    assert(gf);
+    do_dealloc_guestfd(gf);
+}