scanimage appends log to output image when used via sane-airscan

[ericschdt]

I am not sure whether this is an issue of airscan or of scanimage. Apologies in beforehand if I'm wrong now. :)

Setup:

• System: Fedora 34
• sane-airscan: 0.99.26 (release 1.fc34)
• sane-backends 1.0.32
• Printer: Kyocera ECOSYS M6526cdn
  • eSCL: On
  • eSCL over SSL: Off
  • WSD-Scan: On

Issue

After I have worked around the bug(?) in #163 using plain eSCL, I could finally scan successfully using XSane and simplescan, however using scanimage as suggested by the manual:

scanimage -x 100 -y 100 --format=jpeg >image.jpeg 

did not produce something useful.

Result

image.jpeg:

i.e. the output log of the command was appended at the beginning of the output file, which you can see, when you open it with a text or hexeditor:

API: sane_init(): called
loading configuration file /etc/sane.d/airscan.conf
MDNS: AVAHI_CLIENT_S_RUNNING
WSDD: netif addresses update:
WSDD:  + 192.168.178.45
WSDD:  + [IPv6]:acd8%3
WSDD: 192.168.178.45: started discovery, UDP port=56729
WSDD: [IPv6]: started discovery, UDP port=37813
API: sane_get_devices(): called
zeroconf: zeroconf_device_list_get: requested
zeroconf: device_list wait: requested
zeroconf: device_list wait: DNS-SD not finished...
(...)

followed by some garbage (couldn't find the jpeg header) and finally at the end of the file you find the log again.
Same issue for the tiff and pnm format.

Traces

• scanimage-Kyocera-ECOSYS-M6526cdn.txt
• scanimage-zeroconf.txt
• The scanimage-Kyocera-ECOSYS-M6526cdn.tar files containes the correct scanned image.