[Qemu-devel] [PATCH 13/19] qemu-char: Chardev open error reporting, parport part

[Markus Armbruster]

Unlike many other backends, these leave open error reporting to their
caller.  Because the caller doesn't know what went wrong, this results
in a pretty useless error message.

Change them to report their errors themselves.  Improves user-hostile
messages like this one for "-chardev tty,id=foo,path=/dev/parport0"

    chardev: opening backend "parport" failed

to

    qemu-system-x86_64: -chardev parport,id=foo,path=/dev/parport0: Can't open 
'/dev/parport0': Permission denied
    chardev: opening backend "parport" failed

The useless "opening backend failed" message will be cleaned up
shortly.

Signed-off-by: Markus Armbruster <arm...@redhat.com>
---
 qemu-char.c |   21 ++++++++++++++++++---
 1 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 1ff7f4b..ecbb595 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -1371,14 +1371,18 @@ static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
     ParallelCharDriver *drv;
     int fd;
 
+    if (!filename) {
+        error_report("parport character device requires parameter path");
+        return NULL;
+    }
+
     TFR(fd = qemu_open(filename, O_RDWR));
     if (fd < 0) {
-        return NULL;
+        goto err;
     }
 
     if (ioctl(fd, PPCLAIM) < 0) {
-        close(fd);
-        return NULL;
+        goto err;
     }
 
     drv = g_malloc0(sizeof(ParallelCharDriver));
@@ -1394,6 +1398,11 @@ static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
     qemu_chr_generic_open(chr);
 
     return chr;
+
+err:
+    error_report("Can't open '%s': %s", filename, strerror(errno));
+    close(fd);
+    return NULL;
 }
 #endif /* __linux__ */
 
@@ -1441,8 +1450,14 @@ static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
     CharDriverState *chr;
     int fd;
 
+    if (!filename) {
+        error_report("parport character device requires parameter path");
+        return NULL;
+    }
+
     fd = qemu_open(filename, O_RDWR);
     if (fd < 0) {
+        error_report("Can't open '%s': %s", filename, strerror(errno));
         return NULL;
     }
 
-- 
1.7.6.5