chardev: src buffer const for write functions

Make source buffers const for char be write functions.
This allows using buffers returned by fifo as buf parameter and source buffer
should not be changed by write functions anyway.

Signed-off-by: Arwed Meyer <arwed.meyer@gmx.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220911181840.8933-3-arwed.meyer@gmx.de>

chardev/char.c

@@ -193,7 +193,7 @@ int qemu_chr_be_can_write(Chardev *s)
     return be->chr_can_read(be->opaque);
 }
 
-void qemu_chr_be_write_impl(Chardev *s, uint8_t *buf, int len)
+void qemu_chr_be_write_impl(Chardev *s, const uint8_t *buf, int len)
 {
     CharBackend *be = s->be;
 
@@ -202,7 +202,7 @@ void qemu_chr_be_write_impl(Chardev *s, uint8_t *buf, int len)
     }
 }
 
-void qemu_chr_be_write(Chardev *s, uint8_t *buf, int len)
+void qemu_chr_be_write(Chardev *s, const uint8_t *buf, int len)
 {
     if (qemu_chr_replay(s)) {
         if (replay_mode == REPLAY_MODE_PLAY) {

include/chardev/char.h

@@ -186,7 +186,7 @@ int qemu_chr_be_can_write(Chardev *s);
  * the caller should call @qemu_chr_be_can_write to determine how much data
  * the front end can currently accept.
  */
-void qemu_chr_be_write(Chardev *s, uint8_t *buf, int len);
+void qemu_chr_be_write(Chardev *s, const uint8_t *buf, int len);
 
 /**
  * qemu_chr_be_write_impl:
@@ -195,7 +195,7 @@ void qemu_chr_be_write(Chardev *s, uint8_t *buf, int len);
  *
  * Implementation of back end writing. Used by replay module.
  */
-void qemu_chr_be_write_impl(Chardev *s, uint8_t *buf, int len);
+void qemu_chr_be_write_impl(Chardev *s, const uint8_t *buf, int len);
 
 /**
  * qemu_chr_be_update_read_handlers:

include/sysemu/replay.h

@@ -198,7 +198,7 @@ uint64_t blkreplay_next_id(void);
 /*! Registers char driver to save it's events */
 void replay_register_char_driver(struct Chardev *chr);
 /*! Saves write to char device event to the log */
-void replay_chr_be_write(struct Chardev *s, uint8_t *buf, int len);
+void replay_chr_be_write(struct Chardev *s, const uint8_t *buf, int len);
 /*! Writes char write return value to the replay log. */
 void replay_char_write_event_save(int res, int offset);
 /*! Reads char write return value from the replay log. */

replay/replay-char.c

@@ -48,7 +48,7 @@ void replay_register_char_driver(Chardev *chr)
     char_drivers[drivers_count++] = chr;
 }
 
-void replay_chr_be_write(Chardev *s, uint8_t *buf, int len)
+void replay_chr_be_write(Chardev *s, const uint8_t *buf, int len)
 {
     CharEvent *event = g_new0(CharEvent, 1);
 

stubs/replay-tools.c

@@ -53,7 +53,7 @@ void replay_register_char_driver(struct Chardev *chr)
 {
 }
 
-void replay_chr_be_write(struct Chardev *s, uint8_t *buf, int len)
+void replay_chr_be_write(struct Chardev *s, const uint8_t *buf, int len)
 {
     abort();
 }