semihosting: Split out semihost_sys_close

Split out the non-ARM specific portions of SYS_CLOSE to a
reusable function.  This handles all GuestFD.

Note that gdb_do_syscall %x reads target_ulong, not int.

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

include/semihosting/syscalls.h

@@ -22,4 +22,7 @@ void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
                        target_ulong fname, target_ulong fname_len,
                        int gdb_flags, int mode);
 
+void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd);
+
 #endif /* SEMIHOSTING_SYSCALLS_H */

semihosting/arm-compat-semi.c

@@ -276,7 +276,6 @@ common_semi_flen_cb(CPUState *cs, target_ulong ret, target_ulong err)
  * do the work and return the required return value to the guest
  * via common_semi_cb.
  */
-typedef void sys_closefn(CPUState *cs, GuestFD *gf);
 typedef void sys_writefn(CPUState *cs, GuestFD *gf,
                          target_ulong buf, uint32_t len);
 typedef void sys_readfn(CPUState *cs, GuestFD *gf,
@@ -285,23 +284,6 @@ typedef void sys_isattyfn(CPUState *cs, GuestFD *gf);
 typedef void sys_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset);
 typedef void sys_flenfn(CPUState *cs, GuestFD *gf);
 
-static void host_closefn(CPUState *cs, GuestFD *gf)
-{
-    int ret;
-    /*
-     * Only close the underlying host fd if it's one we opened on behalf
-     * of the guest in SYS_OPEN.
-     */
-    if (gf->hostfd == STDIN_FILENO ||
-        gf->hostfd == STDOUT_FILENO ||
-        gf->hostfd == STDERR_FILENO) {
-        ret = 0;
-    } else {
-        ret = close(gf->hostfd);
-    }
-    common_semi_cb(cs, ret, ret ? errno : 0);
-}
-
 static void host_writefn(CPUState *cs, GuestFD *gf,
                          target_ulong buf, uint32_t len)
 {
@@ -362,11 +344,6 @@ static void host_flenfn(CPUState *cs, GuestFD *gf)
     }
 }
 
-static void gdb_closefn(CPUState *cs, GuestFD *gf)
-{
-    gdb_do_syscall(common_semi_cb, "close,%x", gf->hostfd);
-}
-
 static void gdb_writefn(CPUState *cs, GuestFD *gf,
                         target_ulong buf, uint32_t len)
 {
@@ -414,12 +391,6 @@ static const uint8_t featurefile_data[] = {
     SH_EXT_EXIT_EXTENDED | SH_EXT_STDOUT_STDERR, /* Feature byte 0 */
 };
 
-static void staticfile_closefn(CPUState *cs, GuestFD *gf)
-{
-    /* Nothing to do */
-    common_semi_cb(cs, 0, 0);
-}
-
 static void staticfile_writefn(CPUState *cs, GuestFD *gf,
                                target_ulong buf, uint32_t len)
 {
@@ -468,7 +439,6 @@ static void staticfile_flenfn(CPUState *cs, GuestFD *gf)
 }
 
 typedef struct GuestFDFunctions {
-    sys_closefn *closefn;
     sys_writefn *writefn;
     sys_readfn *readfn;
     sys_isattyfn *isattyfn;
@@ -478,7 +448,6 @@ typedef struct GuestFDFunctions {
 
 static const GuestFDFunctions guestfd_fns[] = {
     [GuestFDHost] = {
-        .closefn = host_closefn,
         .writefn = host_writefn,
         .readfn = host_readfn,
         .isattyfn = host_isattyfn,
@@ -486,7 +455,6 @@ static const GuestFDFunctions guestfd_fns[] = {
         .flenfn = host_flenfn,
     },
     [GuestFDGDB] = {
-        .closefn = gdb_closefn,
         .writefn = gdb_writefn,
         .readfn = gdb_readfn,
         .isattyfn = gdb_isattyfn,
@@ -494,7 +462,6 @@ static const GuestFDFunctions guestfd_fns[] = {
         .flenfn = gdb_flenfn,
     },
     [GuestFDStatic] = {
-        .closefn = staticfile_closefn,
         .writefn = staticfile_writefn,
         .readfn = staticfile_readfn,
         .isattyfn = staticfile_isattyfn,
@@ -586,13 +553,7 @@ void do_common_semihosting(CPUState *cs)
 
     case TARGET_SYS_CLOSE:
         GET_ARG(0);
-
-        gf = get_guestfd(arg0);
-        if (!gf) {
-            goto do_badf;
-        }
-        guestfd_fns[gf->type].closefn(cs, gf);
-        dealloc_guestfd(arg0);
+        semihost_sys_close(cs, common_semi_cb, arg0);
         break;
 
     case TARGET_SYS_WRITEC:

semihosting/guestfd.c

@@ -49,6 +49,11 @@ int alloc_guestfd(void)
     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.
@@ -119,5 +124,5 @@ void dealloc_guestfd(int guestfd)
     GuestFD *gf = do_get_guestfd(guestfd);
 
     assert(gf);
-    gf->type = GuestFDUnused;
+    do_dealloc_guestfd(gf);
 }

semihosting/syscalls.c

@@ -94,6 +94,12 @@ static void gdb_open(CPUState *cs, gdb_syscall_complete_cb complete,
                    fname, len, (target_ulong)gdb_flags, (target_ulong)mode);
 }
 
+static void gdb_close(CPUState *cs, gdb_syscall_complete_cb complete,
+                      GuestFD *gf)
+{
+    gdb_do_syscall(complete, "close,%x", (target_ulong)gf->hostfd);
+}
+
 /*
  * Host semihosting syscall implementations.
  */
@@ -140,6 +146,23 @@ static void host_open(CPUState *cs, gdb_syscall_complete_cb complete,
     unlock_user(p, fname, 0);
 }
 
+static void host_close(CPUState *cs, gdb_syscall_complete_cb complete,
+                       GuestFD *gf)
+{
+    /*
+     * Only close the underlying host fd if it's one we opened on behalf
+     * of the guest in SYS_OPEN.
+     */
+    if (gf->hostfd != STDIN_FILENO &&
+        gf->hostfd != STDOUT_FILENO &&
+        gf->hostfd != STDERR_FILENO &&
+        close(gf->hostfd) < 0) {
+        complete(cs, -1, errno);
+    } else {
+        complete(cs, 0, 0);
+    }
+}
+
 /*
  * Syscall entry points.
  */
@@ -154,3 +177,27 @@ void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
         host_open(cs, complete, fname, fname_len, gdb_flags, mode);
     }
 }
+
+void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, int fd)
+{
+    GuestFD *gf = get_guestfd(fd);
+
+    if (!gf) {
+        complete(cs, -1, EBADF);
+        return;
+    }
+    switch (gf->type) {
+    case GuestFDGDB:
+        gdb_close(cs, complete, gf);
+        break;
+    case GuestFDHost:
+        host_close(cs, complete, gf);
+        break;
+    case GuestFDStatic:
+        complete(cs, 0, 0);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    dealloc_guestfd(fd);
+}