[Qemu-devel] [PATCH 07/22] qemu-error: Introduce get_errno_string()

[Luiz Capitulino]

There are error handling functions in QEMU which print errno codes
to the user. While it's debatable if this is good from a user
perspective, sometimes it's the best you can do because it's what
system calls return and this is also useful for debugging.

So, we need a way to expose those codes in QMP. We can't use the
codes themselfs because they may vary between systems.

The best solution I can think of is returning the string
representation of the name. For example, EIO becomes "EIO".

This is what get_errno_string() does.

Signed-off-by: Luiz Capitulino <address@hidden>
---
 qemu-error.c |   25 +++++++++++++++++++++++++
 qemu-error.h |    1 +
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/qemu-error.c b/qemu-error.c
index 5a35e7c..55ce133 100644
--- a/qemu-error.c
+++ b/qemu-error.c
@@ -207,3 +207,28 @@ void error_report(const char *fmt, ...)
     va_end(ap);
     error_printf("\n");
 }
+
+/*
+ * This is probably only useful for QMP
+ */
+const char *get_errno_string(int err)
+{
+    assert(err < 0);
+
+    switch (err) {
+    case -EINVAL:
+        return "EINVAL";
+    case -EIO:
+        return "EIO";
+    case -ENOENT:
+        return "ENOENT";
+    case -ENOMEDIUM:
+        return "ENOMEDIUM";
+    case -ENOTSUP:
+        return "ENOTSUP";
+    default:
+        return "unknown";
+    }
+
+    abort();
+}
diff --git a/qemu-error.h b/qemu-error.h
index a45609f..bf2b890 100644
--- a/qemu-error.h
+++ b/qemu-error.h
@@ -38,4 +38,5 @@ void error_print_loc(void);
 void error_set_progname(const char *argv0);
 void error_report(const char *fmt, ...) __attribute__ ((format(printf, 1, 2)));
 
+const char *get_errno_string(int err);
 #endif
-- 
1.7.1.rc1.12.ga6018