#478 ar -M cannot open large archives

[lantw44]

When I use ar -M to open a large archive, it fails with the following message:

ar: warning: 'OPEN' failed: Invalid argument

ktrace shows the following message:

CALL  mmap(0,0x191464cec,0x1<PROT_READ>,0x1<MAP_SHARED>,0x4,0)
RET   mmap 34376515584/0x801000000
CALL  write(0x3,0x801000000,0x191464cec)
RET   write -1 errno 22 Invalid argument

0x191464cec is the size of the archive (6.3 GiB). It may be too large for the write system call on FreeBSD.

[Ed Maste]

Indeed. From write(2):

write(int fd, const void *buf, size_t nbytes);
...

[EINVAL]           The value nbytes is greater than INT_MAX.

[Ed Maste]

What version of FreeBSD are you using?

[lantw44]

FreeBSD 10.1-RELEASE

[Ed Maste]

Thanks for reporting - see FreeBSD PR https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=196666

You may be able to work around this with a sysctl setting:

# sysctl debug.iosize_max_clamp=0

but I believe a code change ought to be made so that this works "out of the box," perhaps by calling write() in a loop with a limited amount of data sent at a time