Names of user-provided fw_cfg items are supposed to start
with "opt/". However FW_CFG_DATA_GENERATOR items are generated
by QEMU, so allow the "etc/" namespace in this specific case.
Reviewed-by: Laszlo Ersek <ler...@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
v8: addressed Laszlo's comments
- reword commit description
- invert nonempty_str() condition
- new comment in docs/specs/fw_cfg.txt
---
docs/specs/fw_cfg.txt | 4 ++++
softmmu/vl.c | 8 +++++++-
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
index bc16daa38a..3e6d586f66 100644
--- a/docs/specs/fw_cfg.txt
+++ b/docs/specs/fw_cfg.txt
@@ -258,4 +258,8 @@ Prefix "opt/org.qemu/" is reserved for QEMU itself.
Use of names not beginning with "opt/" is potentially dangerous and
entirely unsupported. QEMU will warn if you try.
+Use of names not beginning with "opt/" is tolerated with 'gen_id' (that
+is, the warning is suppressed), but you must know exactly what you're
+doing.
+
All externally provided fw_cfg items are read-only to the guest.
diff --git a/softmmu/vl.c b/softmmu/vl.c
index a9bce2a1b1..ff6732d1fb 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2049,7 +2049,13 @@ static int parse_fw_cfg(void *opaque, QemuOpts *opts,
Error **errp)
FW_CFG_MAX_FILE_PATH - 1);
return -1;
}
- if (strncmp(name, "opt/", 4) != 0) {
+ if (nonempty_str(gen_id)) {
+ /*
+ * In this particular case where the content is populated
+ * internally, the "etc/" namespace protection is relaxed,
+ * so do not emit a warning.
+ */
+ } else if (strncmp(name, "opt/", 4) != 0) {
warn_report("externally provided fw_cfg item names "
"should be prefixed with \"opt/\"");
}
--
2.21.3
