semihosting: Split out semihost_sys_write

Split out the non-ARM specific portions of SYS_WRITE to a
reusable function.  This handles all GuestFD.  This removes
the last use of common_semi_syscall_len.

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

@@ -33,4 +33,10 @@ void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
 void semihost_sys_read_gf(CPUState *cs, gdb_syscall_complete_cb complete,
                           GuestFD *gf, target_ulong buf, target_ulong len);
 
+void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd, target_ulong buf, target_ulong len);
+
+void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
+                           GuestFD *gf, target_ulong buf, target_ulong len);
+
 #endif /* SEMIHOSTING_SYSCALLS_H */

semihosting/arm-compat-semi.c

@@ -215,8 +215,6 @@ static inline uint32_t get_swi_errno(CPUState *cs)
 #endif
 }
 
-static target_ulong common_semi_syscall_len;
-
 static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
 {
     if (err) {
@@ -230,9 +228,6 @@ static void common_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
         /* Fixup syscalls that use nonstardard return conventions.  */
         target_ulong reg0 = common_semi_arg(cs, 0);
         switch (reg0) {
-        case TARGET_SYS_WRITE:
-            ret = common_semi_syscall_len - ret;
-            break;
         case TARGET_SYS_SEEK:
             ret = 0;
             break;
@@ -294,30 +289,10 @@ 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_writefn(CPUState *cs, GuestFD *gf,
-                         target_ulong buf, uint32_t len);
 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_writefn(CPUState *cs, GuestFD *gf,
-                         target_ulong buf, uint32_t len)
-{
-    CPUArchState *env = cs->env_ptr;
-    uint32_t ret = 0;
-    char *s = lock_user(VERIFY_READ, buf, len, 1);
-    (void) env; /* Used in arm softmmu lock_user implicitly */
-    if (s) {
-        ret = write(gf->hostfd, s, len);
-        unlock_user(s, buf, 0);
-        if (ret == (uint32_t)-1) {
-            ret = 0;
-        }
-    }
-    /* Return bytes not written, on error as well. */
-    common_semi_cb(cs, len - ret, 0);
-}
-
 static void host_isattyfn(CPUState *cs, GuestFD *gf)
 {
     common_semi_cb(cs, isatty(gf->hostfd), 0);
@@ -340,13 +315,6 @@ static void host_flenfn(CPUState *cs, GuestFD *gf)
     }
 }
 
-static void gdb_writefn(CPUState *cs, GuestFD *gf,
-                        target_ulong buf, uint32_t len)
-{
-    common_semi_syscall_len = len;
-    gdb_do_syscall(common_semi_cb, "write,%x,%x,%x", gf->hostfd, buf, len);
-}
-
 static void gdb_isattyfn(CPUState *cs, GuestFD *gf)
 {
     gdb_do_syscall(common_semi_cb, "isatty,%x", gf->hostfd);
@@ -380,13 +348,6 @@ static const uint8_t featurefile_data[] = {
     SH_EXT_EXIT_EXTENDED | SH_EXT_STDOUT_STDERR, /* Feature byte 0 */
 };
 
-static void staticfile_writefn(CPUState *cs, GuestFD *gf,
-                               target_ulong buf, uint32_t len)
-{
-    /* This fd can never be open for writing */
-    common_semi_cb(cs, -1, EBADF);
-}
-
 static void staticfile_isattyfn(CPUState *cs, GuestFD *gf)
 {
     common_semi_cb(cs, 0, 0);
@@ -404,7 +365,6 @@ static void staticfile_flenfn(CPUState *cs, GuestFD *gf)
 }
 
 typedef struct GuestFDFunctions {
-    sys_writefn *writefn;
     sys_isattyfn *isattyfn;
     sys_seekfn *seekfn;
     sys_flenfn *flenfn;
@@ -412,19 +372,16 @@ typedef struct GuestFDFunctions {
 
 static const GuestFDFunctions guestfd_fns[] = {
     [GuestFDHost] = {
-        .writefn = host_writefn,
         .isattyfn = host_isattyfn,
         .seekfn = host_seekfn,
         .flenfn = host_flenfn,
     },
     [GuestFDGDB] = {
-        .writefn = gdb_writefn,
         .isattyfn = gdb_isattyfn,
         .seekfn = gdb_seekfn,
         .flenfn = gdb_flenfn,
     },
     [GuestFDStatic] = {
-        .writefn = staticfile_writefn,
         .isattyfn = staticfile_isattyfn,
         .seekfn = staticfile_seekfn,
         .flenfn = staticfile_flenfn,
@@ -449,7 +406,6 @@ void do_common_semihosting(CPUState *cs)
     char * s;
     int nr;
     uint32_t ret;
-    uint32_t len;
     GuestFD *gf;
     int64_t elapsed;
 
@@ -531,13 +487,7 @@ void do_common_semihosting(CPUState *cs)
         GET_ARG(0);
         GET_ARG(1);
         GET_ARG(2);
-        len = arg2;
+        semihost_sys_write(cs, common_semi_rw_cb, arg0, arg1, arg2);
-
-        gf = get_guestfd(arg0);
-        if (!gf) {
-            goto do_badf;
-        }
-        guestfd_fns[gf->type].writefn(cs, gf, arg1, len);
         break;
 
     case TARGET_SYS_READ:

semihosting/syscalls.c

@@ -107,6 +107,13 @@ static void gdb_read(CPUState *cs, gdb_syscall_complete_cb complete,
                    (target_ulong)gf->hostfd, buf, len);
 }
 
+static void gdb_write(CPUState *cs, gdb_syscall_complete_cb complete,
+                      GuestFD *gf, target_ulong buf, target_ulong len)
+{
+    gdb_do_syscall(complete, "write,%x,%x,%x",
+                   (target_ulong)gf->hostfd, buf, len);
+}
+
 /*
  * Host semihosting syscall implementations.
  */
@@ -193,6 +200,22 @@ static void host_read(CPUState *cs, gdb_syscall_complete_cb complete,
     }
 }
 
+static void host_write(CPUState *cs, gdb_syscall_complete_cb complete,
+                       GuestFD *gf, target_ulong buf, target_ulong len)
+{
+    CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+    void *ptr = lock_user(VERIFY_READ, buf, len, 1);
+    ssize_t ret;
+
+    if (!ptr) {
+        complete(cs, -1, EFAULT);
+        return;
+    }
+    ret = write(gf->hostfd, ptr, len);
+    complete(cs, ret, ret == -1 ? errno : 0);
+    unlock_user(ptr, buf, 0);
+}
+
 /*
  * Static file semihosting syscall implementations.
  */
@@ -286,3 +309,34 @@ void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
         complete(cs, -1, EBADF);
     }
 }
+
+void semihost_sys_write_gf(CPUState *cs, gdb_syscall_complete_cb complete,
+                           GuestFD *gf, target_ulong buf, target_ulong len)
+{
+    switch (gf->type) {
+    case GuestFDGDB:
+        gdb_write(cs, complete, gf, buf, len);
+        break;
+    case GuestFDHost:
+        host_write(cs, complete, gf, buf, len);
+        break;
+    case GuestFDStatic:
+        /* Static files are never open for writing: EBADF. */
+        complete(cs, -1, EBADF);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+}
+
+void semihost_sys_write(CPUState *cs, gdb_syscall_complete_cb complete,
+                        int fd, target_ulong buf, target_ulong len)
+{
+    GuestFD *gf = get_guestfd(fd);
+
+    if (gf) {
+        semihost_sys_write_gf(cs, complete, gf, buf, len);
+    } else {
+        complete(cs, -1, EBADF);
+    }
+}