compiler wrapper trying to create temporary files in /dev

[mischief]

hi,

without any additional setup or ceremony, i built HEAD with rustc/cargo 1.81.0 in gentoo and invoked sccache like the readme suggests: https://github.com/mozilla/sccache?tab=readme-ov-file#usage

mischief@beast:~/src/sccache $ cargo build --release
   Compiling libc v0.2.155
   Compiling proc-macro2 v1.0.75
   Compiling unicode-ident v1.0.12
...
    Finished `release` profile [optimized] target(s) in 3m 24s

i'm not a rust person, but i find it odd that sccache would attempt to make a temporary file in /dev/. a user program should never do this.

this occurred after more than 1 invocation of sccache with the same parameters. the first invocation had no error.

mischief@beast:~/src/sccache $ ./target/release/sccache cc -o /dev/null -c ~/code/c/fbufsize.c
sccache: encountered fatal error
sccache: error: Permission denied (os error 13) at path "/dev/.tmp48KCJX"
sccache: caused by: Permission denied (os error 13) at path "/dev/.tmp48KCJX"

fbufsize.c is nothing special, just a trivial program i had laying around.

#include <stdio.h>
#include <stdio_ext.h>

int main(void)
{
        setvbuf(stdout, NULL, _IONBF, 0);
        setvbuf(stderr, NULL, _IONBF, 0);
        printf("%ld\n", __fbufsize(stdout));
        printf("%ld\n", __fbufsize(stderr));
        return 0;
}

[Xuanwo]

./target/release/sccache cc -o /dev/null -c ~/code/c/fbufsize.c

Hi, what will happen if we change -o /dev/null?