new file mode 100644
@@ -0,0 +1,25 @@
+/*
+ * Syscall implementations for semihosting.
+ *
+ * Copyright (c) 2022 Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef SEMIHOSTING_SYSCALLS_H
+#define SEMIHOSTING_SYSCALLS_H
+
+/*
+ * Argument loading from the guest is performed by the caller;
+ * results are returned via the 'complete' callback.
+ *
+ * String operands are in address/len pairs. The len argument may be 0
+ * (when the semihosting abi does not already provide the length),
+ * or non-zero (where it should include the terminating zero).
+ */
+
+void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
+ target_ulong fname, target_ulong fname_len,
+ int gdb_flags, int mode);
+
+#endif /* SEMIHOSTING_SYSCALLS_H */
@@ -32,12 +32,13 @@
*/
#include "qemu/osdep.h"
+#include "qemu/timer.h"
+#include "exec/gdbstub.h"
#include "semihosting/semihost.h"
#include "semihosting/console.h"
#include "semihosting/common-semi.h"
#include "semihosting/guestfd.h"
-#include "qemu/timer.h"
-#include "exec/gdbstub.h"
+#include "semihosting/syscalls.h"
#ifdef CONFIG_USER_ONLY
#include "qemu.h"
@@ -98,21 +99,6 @@ static int gdb_open_modeflags[12] = {
GDB_O_RDWR | GDB_O_CREAT | GDB_O_APPEND,
};
-static int open_modeflags[12] = {
- O_RDONLY,
- O_RDONLY | O_BINARY,
- O_RDWR,
- O_RDWR | O_BINARY,
- O_WRONLY | O_CREAT | O_TRUNC,
- O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
- O_RDWR | O_CREAT | O_TRUNC,
- O_RDWR | O_CREAT | O_TRUNC | O_BINARY,
- O_WRONLY | O_CREAT | O_APPEND,
- O_WRONLY | O_CREAT | O_APPEND | O_BINARY,
- O_RDWR | O_CREAT | O_APPEND,
- O_RDWR | O_CREAT | O_APPEND | O_BINARY
-};
-
#ifndef CONFIG_USER_ONLY
/**
@@ -284,20 +270,6 @@ common_semi_flen_cb(CPUState *cs, target_ulong ret, target_ulong err)
common_semi_cb(cs, ret, err);
}
-static int common_semi_open_guestfd;
-
-static void
-common_semi_open_cb(CPUState *cs, target_ulong ret, target_ulong err)
-{
- if (err) {
- dealloc_guestfd(common_semi_open_guestfd);
- } else {
- associate_guestfd(common_semi_open_guestfd, ret);
- ret = common_semi_open_guestfd;
- }
- common_semi_cb(cs, ret, err);
-}
-
/*
* Types for functions implementing various semihosting calls
* for specific types of guest file descriptor. These must all
@@ -601,22 +573,10 @@ void do_common_semihosting(CPUState *cs)
staticfile_guestfd(ret, featurefile_data,
sizeof(featurefile_data));
}
- } else if (use_gdb_syscalls()) {
- unlock_user(s, arg0, 0);
- common_semi_open_guestfd = alloc_guestfd();
- gdb_do_syscall(common_semi_open_cb,
- "open,%s,%x,1a4", arg0, (int)arg2 + 1,
- gdb_open_modeflags[arg1]);
- break;
} else {
- hostfd = open(s, open_modeflags[arg1], 0644);
- if (hostfd < 0) {
- ret = -1;
- err = errno;
- } else {
- ret = alloc_guestfd();
- associate_guestfd(ret, hostfd);
- }
+ semihost_sys_open(cs, common_semi_cb, arg0, arg2 + 1,
+ gdb_open_modeflags[arg1], 0644);
+ break;
}
unlock_user(s, arg0, 0);
common_semi_cb(cs, ret, err);
@@ -11,6 +11,11 @@
#include "qemu/osdep.h"
#include "exec/gdbstub.h"
#include "semihosting/guestfd.h"
+#ifdef CONFIG_USER_ONLY
+#include "qemu.h"
+#else
+#include "semihosting/softmmu-uaccess.h"
+#endif
static GArray *guestfd_array;
new file mode 100644
@@ -0,0 +1,156 @@
+/*
+ * Syscall implementations for semihosting.
+ *
+ * Copyright (c) 2022 Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "exec/gdbstub.h"
+#include "semihosting/guestfd.h"
+#include "semihosting/syscalls.h"
+#ifdef CONFIG_USER_ONLY
+#include "qemu.h"
+#else
+#include "semihosting/softmmu-uaccess.h"
+#endif
+
+
+/*
+ * Validate or compute the length of the string (including terminator).
+ */
+static int validate_strlen(CPUState *cs, target_ulong str, target_ulong tlen)
+{
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ char c;
+
+ if (tlen == 0) {
+ ssize_t slen = target_strlen(str);
+
+ if (slen < 0) {
+ return -EFAULT;
+ }
+ if (slen >= INT32_MAX) {
+ return -ENAMETOOLONG;
+ }
+ return slen + 1;
+ }
+ if (tlen > INT32_MAX) {
+ return -ENAMETOOLONG;
+ }
+ if (get_user_u8(c, str + tlen - 1)) {
+ return -EFAULT;
+ }
+ if (c != 0) {
+ return -EINVAL;
+ }
+ return tlen;
+}
+
+static int validate_lock_user_string(char **pstr, CPUState *cs,
+ target_ulong tstr, target_ulong tlen)
+{
+ int ret = validate_strlen(cs, tstr, tlen);
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ char *str = NULL;
+
+ if (ret > 0) {
+ str = lock_user(VERIFY_READ, tstr, ret, true);
+ ret = str ? 0 : -EFAULT;
+ }
+ *pstr = str;
+ return ret;
+}
+
+/*
+ * GDB semihosting syscall implementations.
+ */
+
+static gdb_syscall_complete_cb gdb_open_complete;
+
+static void gdb_open_cb(CPUState *cs, target_ulong ret, target_ulong err)
+{
+ if (!err) {
+ int guestfd = alloc_guestfd();
+ associate_guestfd(guestfd, ret);
+ ret = guestfd;
+ }
+ gdb_open_complete(cs, ret, err);
+}
+
+static void gdb_open(CPUState *cs, gdb_syscall_complete_cb complete,
+ target_ulong fname, target_ulong fname_len,
+ int gdb_flags, int mode)
+{
+ int len = validate_strlen(cs, fname, fname_len);
+ if (len < 0) {
+ complete(cs, -1, -len);
+ return;
+ }
+
+ gdb_open_complete = complete;
+ gdb_do_syscall(gdb_open_cb, "open,%s,%x,%x",
+ fname, len, (target_ulong)gdb_flags, (target_ulong)mode);
+}
+
+/*
+ * Host semihosting syscall implementations.
+ */
+
+static void host_open(CPUState *cs, gdb_syscall_complete_cb complete,
+ target_ulong fname, target_ulong fname_len,
+ int gdb_flags, int mode)
+{
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ char *p;
+ int ret, host_flags;
+
+ ret = validate_lock_user_string(&p, cs, fname, fname_len);
+ if (ret < 0) {
+ complete(cs, -1, -ret);
+ return;
+ }
+
+ if (gdb_flags & GDB_O_WRONLY) {
+ host_flags = O_WRONLY;
+ } else if (gdb_flags & GDB_O_RDWR) {
+ host_flags = O_RDWR;
+ } else {
+ host_flags = O_RDONLY;
+ }
+ if (gdb_flags & GDB_O_CREAT) {
+ host_flags |= O_CREAT;
+ }
+ if (gdb_flags & GDB_O_TRUNC) {
+ host_flags |= O_TRUNC;
+ }
+ if (gdb_flags & GDB_O_EXCL) {
+ host_flags |= O_EXCL;
+ }
+
+ ret = open(p, host_flags, mode);
+ if (ret < 0) {
+ complete(cs, -1, errno);
+ } else {
+ int guestfd = alloc_guestfd();
+ associate_guestfd(guestfd, ret);
+ complete(cs, guestfd, 0);
+ }
+ unlock_user(p, fname, 0);
+}
+
+/*
+ * Syscall entry points.
+ */
+
+void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb complete,
+ target_ulong fname, target_ulong fname_len,
+ int gdb_flags, int mode)
+{
+ if (use_gdb_syscalls()) {
+ gdb_open(cs, complete, fname, fname_len, gdb_flags, mode);
+ } else {
+ host_open(cs, complete, fname, fname_len, gdb_flags, mode);
+ }
+}
@@ -1,5 +1,6 @@
specific_ss.add(when: 'CONFIG_SEMIHOSTING', if_true: files(
'guestfd.c',
+ 'syscalls.c',
))
specific_ss.add(when: ['CONFIG_SEMIHOSTING', 'CONFIG_SOFTMMU'], if_true: files(
Split out the non-ARM specific portions of SYS_OPEN to a reusable function. This handles gdb and host file i/o. Add helpers to validate the length of the filename string. Prepare for usage by other semihosting by allowing the filename length parameter to be 0, and calling strlen. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- include/semihosting/syscalls.h | 25 ++++++ semihosting/arm-compat-semi.c | 52 ++--------- semihosting/guestfd.c | 5 ++ semihosting/syscalls.c | 156 +++++++++++++++++++++++++++++++++ semihosting/meson.build | 1 + 5 files changed, 193 insertions(+), 46 deletions(-) create mode 100644 include/semihosting/syscalls.h create mode 100644 semihosting/syscalls.c