Re: clang builds and /var/tmp

[Richard PALO <richard%netbsd.org@localhost>]

Le 21/10/15 10:39, Tobias Nygren a écrit :

> The purpose of /var/tmp is to be a globally writable temp directory.
> If you do "ktrace gcc -o test test.c" you will find that the gcc +
> binutils toolchain too creates many temporary files there, unless -pipe
> is used. A good solution to preserve the life of your ssd is to mount
> tmpfs on /tmp and /var/tmp. But beware that this breaks virecover.
>
> -Tobias

/tmp is naturally already tmpfs (at least on SunOS)...

from `man filesystem'

>       /tmp
>            Temporary files; cleared during the boot operation.
...
>       /var/tmp
>            Files that vary in size or presence during normal system
>            operations. This directory is not cleared during the boot
>            operation. An approved installation location for bundled Solaris
>            software and for add-on system software and applications.
>
>            It is possible to change the default behavior for /var/tmp to clear
>            all of the files except editor temporary files by setting the
>            clean_vartmp property value of the rmtmpfiles service. This is done
>            with the following commands:
>
>              # svccfg -s svc:/system/rmtmpfiles setprop \
>                    options/clean_vartmp = "true"
>              # svcadm refresh svc:/system/rmtmpfiles:default
>
>            The solaris.smf.value.rmtmpfiles authorization is required to
>            modify this property.

why the hell would a /var/tmp be used in the case of pure temporary files?

even mktemp does the right thing:
> richard@omnis:/home/richard/src/tnull$ echo `mktemp`
> /tmp/tmp.GbWcPL
> richard@omnis:/home/richard/src/tnull$ echo  `mktemp -t`
> /tmp/tmp.oUGdPL
> richard@omnis:/home/richard/src/tnull$ echo  `TMPDIR=/var/tmp mktemp`
> /var/tmp/tmp.hIGFPL
> richard@omnis:/home/richard/src/tnull$ echo  `TMPDIR=/var/tmp mktemp -t`
> /var/tmp/tmp.ZfqGPL

I do see now that gcc uses /var/tmp, but even sunstudio does it right 
with /tmp...

Looks as if, for the case of gcc, that in libiberty/make-temp-file.c:
> 115 #ifdef VMS
> 116       /* Try VMS standard temp logical.  */
> 117       base = try_dir ("/sys$scratch", base);
> 118 #else
> 119       base = try_dir (getenv ("TMPDIR"), base);
> 120       base = try_dir (getenv ("TMP"), base);
> 121       base = try_dir (getenv ("TEMP"), base);
> 122 #endif
> 123
> 124 #ifdef P_tmpdir
> 125       /* We really want a directory name here as if concatenated with say \d    ir
> 126          we do not end up with a double \\ which defines an UNC path.  */
> 127       if (strcmp (P_tmpdir, "\\") == 0)
> 128         base = try_dir ("\\.", base);
> 129       else
> 130         base = try_dir (P_tmpdir, base);
> 131 #endif
> 132
> 133       /* Try /var/tmp, /usr/tmp, then /tmp.  */
> 134       base = try_dir (vartmp, base);
> 135       base = try_dir (usrtmp, base);
> 136       base = try_dir (tmp, base);

Always having TMPDIR set should probably get over the issue.

Therefore, it seems pkgsrc could have a TMPDIR in defaults,
overrideable by the user or even the package allowing customisation if
need be.