sysctl sensor error handling

[Alexander Bluhm]

Hi,

I had an hanging sysctl(8) that was compiled with an obsolete header
file.  Struct sensordev was too small, so sysctl(2) failed with
ENOMEM.  But the sysctl(8) program continued with unitialized memory.

# sysctl hw
...
hw.diskcount=2
hw.sensors..temp0=33.00 degC
--> here it hangs in an endless loop

So I would like to catch the error and skip the sensors.

# sysctl hw
...
hw.diskcount=2
sysctl: sensors dev 0: Cannot allocate memory
hw.cpuspeed=2933
...

ok?

bluhm

Index: sbin/sysctl/sysctl.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sbin/sysctl/sysctl.c,v
retrieving revision 1.240
diff -u -p -r1.240 sysctl.c
--- sbin/sysctl/sysctl.c        29 Jan 2019 14:07:15 -0000      1.240
+++ sbin/sysctl/sysctl.c        21 Feb 2019 14:45:52 -0000
@@ -2418,6 +2418,8 @@ sysctl_sensors(char *string, char **bufp
                                        continue;
                                if (errno == ENOENT)
                                        break;
+                               warn("sensors dev %d", dev);
+                               return (-1);
                        }
                        snprintf(buf, sizeof(buf), "%s.%s",
                            string, snsrdev.xname);
@@ -2443,6 +2445,8 @@ sysctl_sensors(char *string, char **bufp
                                continue;
                        if (errno == ENOENT)
                                break;
+                       warn("sensors dev %d", dev);
+                       return (-1);
                }
                if (strcmp(devname, snsrdev.xname) == 0)
                        break;