| Message ID | 1592307754-8844-1-git-send-email-igor.druzhinin@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [for-4.14,v2] tools/xen-ucode: fix error code propagation of microcode load operation | expand |
On 16.06.2020 13:42, Igor Druzhinin wrote: > @@ -62,8 +62,11 @@ int main(int argc, char *argv[]) > > ret = xc_microcode_update(xch, buf, len); > if ( ret ) > + { > fprintf(stderr, "Failed to update microcode. (err: %s)\n", > strerror(errno)); > + return errno; I think you need to latch errno, as fprintf() may in principle run into another error. Jan
On 16/06/2020 13:25, Jan Beulich wrote: > [CAUTION - EXTERNAL EMAIL] DO NOT reply, click links, or open attachments unless you have verified the sender and know the content is safe. > > On 16.06.2020 13:42, Igor Druzhinin wrote: >> @@ -62,8 +62,11 @@ int main(int argc, char *argv[]) >> >> ret = xc_microcode_update(xch, buf, len); >> if ( ret ) >> + { >> fprintf(stderr, "Failed to update microcode. (err: %s)\n", >> strerror(errno)); >> + return errno; > > I think you need to latch errno, as fprintf() may in principle run > into another error. Yes, I also noticed that but the whole file has this problem so I didn't change it here specifically. If fixing the whole file - I'd rather rewrite error reporting completely: return 1 on error, 0 on success, etc. From what I've read returning errno has many incompatibilities and might lead to surprise consequences. I'll send v3 to clean this all up. Igor
diff --git a/tools/misc/xen-ucode.c b/tools/misc/xen-ucode.c index 0c257f4..409cace 100644 --- a/tools/misc/xen-ucode.c +++ b/tools/misc/xen-ucode.c @@ -25,7 +25,7 @@ int main(int argc, char *argv[]) fprintf(stderr, "xen-ucode: Xen microcode updating tool\n" "Usage: %s <microcode blob>\n", argv[0]); - return 0; + return EINVAL; } filename = argv[1]; @@ -62,8 +62,11 @@ int main(int argc, char *argv[]) ret = xc_microcode_update(xch, buf, len); if ( ret ) + { fprintf(stderr, "Failed to update microcode. (err: %s)\n", strerror(errno)); + return errno; + } xc_interface_close(xch);
Otherwise it's impossible to know the reason for a fault or blob rejection inside the automation. While at it, also change return code of incorrect invokation to EINVAL. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> --- Changes in v2: - simply call "return errno". On Linux that seems to be safe as values <=255 are correctly propagated, on non-Linux I couldn't find error codes >127. - return positive value on incorrect invokation --- tools/misc/xen-ucode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)