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[PATCH v3 1/2] util: Introduce qemu_get_host_name()
From: |
Michal Privoznik |
Subject: |
[PATCH v3 1/2] util: Introduce qemu_get_host_name() |
Date: |
Mon, 22 Jun 2020 20:19:35 +0200 |
This function offers operating system agnostic way to fetch host
name. It is implemented for both POSIX-like and Windows systems.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
include/qemu/osdep.h | 10 ++++++++++
util/oslib-posix.c | 35 +++++++++++++++++++++++++++++++++++
util/oslib-win32.c | 13 +++++++++++++
3 files changed, 58 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index ff7c17b857..a795d46b28 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -607,4 +607,14 @@ static inline void qemu_reset_optind(void)
#endif
}
+/**
+ * qemu_get_host_name:
+ * @errp: Error object
+ *
+ * Operating system agnostic way of querying host name.
+ *
+ * Returns allocated hostname (caller should free), NULL on failure.
+ */
+char *qemu_get_host_name(Error **errp);
+
#endif
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 916f1be224..3997ee0442 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -761,3 +761,38 @@ void sigaction_invoke(struct sigaction *action,
}
action->sa_sigaction(info->ssi_signo, &si, NULL);
}
+
+#ifndef HOST_NAME_MAX
+# ifdef _POSIX_HOST_NAME_MAX
+# define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
+# else
+# define HOST_NAME_MAX 255
+# endif
+#endif
+
+char *qemu_get_host_name(Error **errp)
+{
+ long len = -1;
+ g_autofree char *hostname = NULL;
+
+#ifdef _SC_HOST_NAME_MAX
+ len = sysconf(_SC_HOST_NAME_MAX);
+#endif /* _SC_HOST_NAME_MAX */
+
+ if (len < 0) {
+ len = HOST_NAME_MAX;
+ }
+
+ /* Unfortunately, gethostname() below does not guarantee a
+ * NULL terminated string. Therefore, allocate one byte more
+ * to be sure. */
+ hostname = g_new0(char, len + 1);
+
+ if (gethostname(hostname, len) < 0) {
+ error_setg_errno(errp, errno,
+ "cannot get hostname");
+ return NULL;
+ }
+
+ return g_steal_pointer(&hostname);
+}
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index e9b14ab178..3b49d27297 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -808,3 +808,16 @@ bool qemu_write_pidfile(const char *filename, Error **errp)
}
return true;
}
+
+char *qemu_get_host_name(Error **errp)
+{
+ wchar_t tmp[MAX_COMPUTERNAME_LENGTH + 1];
+ DWORD size = G_N_ELEMENTS(tmp);
+
+ if (GetComputerNameW(tmp, &size) == 0) {
+ error_setg_win32(errp, GetLastError(), "failed close handle");
+ return NULL;
+ }
+
+ return g_utf16_to_utf8(tmp, size, NULL, NULL, NULL);
+}
--
2.26.2