Fix bug in semihosting write function

The return value from the SYS_WRITE semihosting operation is 0 if
the call is successful or the number of bytes not written, if there
is an error. The implementation of the write function in the
semihosting driver treats the return value as the number of bytes
written, which is wrong. This patch fixes it.

Change-Id: Id39dac3d17b5eac557408b8995abe90924c85b85

diff --git a/drivers/io/io_semihosting.c b/drivers/io/io_semihosting.c
index 3c92c6d75928a23a873fe2b5458de1d14201a9b3..8e62be1d961c31c1370c367226d69c01c04f6d6d 100644 (file)
--- a/drivers/io/io_semihosting.c
+++ b/drivers/io/io_semihosting.c
@@ -183,7 +183,6 @@ static int sh_file_read(io_entity_t *entity, uintptr_t buffer, size_t length,
 static int sh_file_write(io_entity_t *entity, const uintptr_t buffer,
                size_t length, size_t *length_written)
 {
-       int result = IO_FAIL;
        long sh_result = -1;
        long file_handle;
        size_t bytes = length;
@@ -196,13 +195,9 @@ static int sh_file_write(io_entity_t *entity, const uintptr_t buffer,
 
        sh_result = semihosting_file_write(file_handle, &bytes, buffer);
 
-       if (sh_result >= 0) {
-               *length_written = sh_result;
-               result = IO_SUCCESS;
-       } else
-               result = IO_FAIL;
+       *length_written = length - bytes;
 
-       return result;
+       return (sh_result == 0) ? IO_SUCCESS : IO_FAIL;
 }
 
 

diff --git a/lib/semihosting/semihosting.c b/lib/semihosting/semihosting.c
index 849ec1207e2018926fbdfc9c2f9e4e899397b995..b4f53d2539888671764a8e3905378d96360d85c5 100644 (file)
--- a/lib/semihosting/semihosting.c
+++ b/lib/semihosting/semihosting.c
@@ -125,6 +125,7 @@ long semihosting_file_write(long file_handle,
                            const uintptr_t buffer)
 {
        smh_file_read_write_block_t write_block;
+       long result = -EINVAL;
 
        if ((length == NULL) || (buffer == (uintptr_t)NULL))
                return -EINVAL;
@@ -133,10 +134,12 @@ long semihosting_file_write(long file_handle,
        write_block.buffer = (uintptr_t)buffer; /* cast away const */
        write_block.length = *length;
 
-       *length = semihosting_call(SEMIHOSTING_SYS_WRITE,
+       result = semihosting_call(SEMIHOSTING_SYS_WRITE,
                                   (void *) &write_block);
 
-       return *length;
+       *length = result;
+
+       return (result == 0) ? 0 : -EINVAL;
 }
 
 long semihosting_file_close(long file_handle)