semihosting: Create qemu_semihosting_guestfd_init

For arm-compat, initialize console_{in,out}_gf;
otherwise, initialize stdio file descriptors.

This will go some way to cleaning up arm-compat, and
will allow other semihosting to use normal stdio.

Reviewed-by: Luc Michel <lmichel@kalray.eu>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/semihosting/guestfd.h

@@ -35,6 +35,13 @@ typedef struct GuestFD {
     };
 } GuestFD;
 
+/*
+ * For ARM semihosting, we have a separate structure for routing
+ * data for the console which is outside the guest fd address space.
+ */
+extern GuestFD console_in_gf;
+extern GuestFD console_out_gf;
+
 /**
  * alloc_guestfd:
  *

include/semihosting/semihost.h

@@ -64,5 +64,6 @@ int qemu_semihosting_config_options(const char *opt);
 void qemu_semihosting_chardev_init(void);
 void qemu_semihosting_console_init(Chardev *);
 #endif /* CONFIG_USER_ONLY */
+void qemu_semihosting_guestfd_init(void);
 
 #endif /* SEMIHOST_H */

linux-user/main.c

@@ -54,6 +54,10 @@
 #include "loader.h"
 #include "user-mmap.h"
 
+#ifdef CONFIG_SEMIHOSTING
+#include "semihosting/semihost.h"
+#endif
+
 #ifndef AT_FLAGS_PRESERVE_ARGV0
 #define AT_FLAGS_PRESERVE_ARGV0_BIT 0
 #define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT)
@@ -906,6 +910,11 @@ int main(int argc, char **argv, char **envp)
         }
         gdb_handlesig(cpu, 0);
     }
+
+#ifdef CONFIG_SEMIHOSTING
+    qemu_semihosting_guestfd_init();
+#endif
+
     cpu_loop(env);
     /* never exits */
     return 0;

semihosting/console.c

@@ -190,4 +190,6 @@ void qemu_semihosting_console_init(Chardev *chr)
                                  NULL, NULL, &console,
                                  NULL, true);
     }
+
+    qemu_semihosting_guestfd_init();
 }

semihosting/guestfd.c

@@ -10,15 +10,56 @@
 
 #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.
@@ -30,11 +71,6 @@ int alloc_guestfd(void)
 {
     guint i;
 
-    if (!guestfd_array) {
-        /* New entries zero-initialized, i.e. type GuestFDUnused */
-        guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD));
-    }
-
     /* 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);
@@ -61,11 +97,7 @@ static void do_dealloc_guestfd(GuestFD *gf)
  */
 static GuestFD *do_get_guestfd(int guestfd)
 {
-    if (!guestfd_array) {
+    if (guestfd < 0 || guestfd >= guestfd_array->len) {
-        return NULL;
-    }
-
-    if (guestfd <= 0 || guestfd >= guestfd_array->len) {
         return NULL;
     }