cmds/core/df: skip mount point on permission error

[binjip978]

No description provided.

[binjip978]

current version fails on fedora, but runs fine under root
2023/11/26 21:25:48 mountinfo()=_,"permission denied", want: _,nil

maybe error message can be improved as well...

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (9f32fba) 75.16% compared to head (5c5c1d1) 75.32%.

Files	Patch %	Lines
cmds/core/df/df.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2813      +/-   ##
==========================================
+ Coverage   75.16%   75.32%   +0.15%     
==========================================
  Files         432      432              
  Lines       42965    42967       +2     
==========================================
+ Hits        32295    32364      +69     
+ Misses      10670    10603      -67     

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[rminnich]

this could confuse people, however: running df on one directory and have it do nothing at all? e.g.
% df /abc
%

People are going to think it's doing nothing or broken. Does it really do this on the standard df, just have a silent failure?

It may need two return params, maybe, if this is the case. What is fedora doing? Can you trace it to a kernel difference?

[binjip978]

this could confuse people, however: running df on one directory and have it do nothing at all? e.g. % df /abc %

People are going to think it's doing nothing or broken. Does it really do this on the standard df, just have a silent failure?

It may need two return params, maybe, if this is the case. What is fedora doing? Can you trace it to a kernel difference?

I found this issue because tests for df command on fedora is falling now. We can write and error log to stderr, but I found that df just ignores such error and move on.

Fedora df is doing this, when I execute df with no parameters.

statfs("/proc/sys/fs/binfmt_misc", {f_type=BINFMTFS_MAGIC, f_bsize=4096, f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV|ST_NOEXEC|ST_RELATIME}) = 0
statfs("/sys/kernel/debug/tracing", 0x7ffea36266e0) = -1 EACCES (Permission denied)
statfs("/sys/fs/cgroup/net_cls", {f_type=CGROUP_SUPER_MAGIC, f_bsize=4096, f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={val=[0, 0]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_RELATIME}) = 0
statfs("/run/user/1000", {f_type=TMPFS_MAGIC, f_bsize=4096, f_blocks=608794, f_bfree=608751, f_bavail=608751, f_files=608794, f_ffree=608631, f_fsid={val=[0x52c35c6f, 0xb1cd1f7b]}, f_namelen=255, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV|ST_RELATIME}) = 0
statfs("/run/user/1000/gvfs", {f_type=FUSE_SUPER_MAGIC, f_bsize=4096, f_blocks=0, f_bfree=0, f_bavail=0, f_files=0, f_ffree=0, f_fsid={val=[0, 0]}, f_namelen=1024, f_frsize=4096, f_flags=ST_VALID|ST_NOSUID|ST_NODEV|ST_RELATIME}) = 0
newfstatat(1, "", {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0), ...}, AT_EMPTY_PATH) = 0
write(1, "Filesystem     1K-blocks     Use"..., 60) = 60
write(1, "/dev/dm-0      498426880 1559012"..., 51) = 51
write(1, "devtmpfs            4096        "..., 54) = 54
write(1, "tmpfs           12175880        "..., 58) = 58
write(1, "efivarfs             154       7"..., 75) = 75
write(1, "tmpfs            4870352     212"..., 54) = 54
write(1, "/dev/dm-0      498426880 1559012"..., 55) = 55
write(1, "/dev/nvme0n1p2    996780   31486"..., 55) = 55
write(1, "tmpfs           12175880       1"..., 54) = 54
write(1, "/dev/nvme0n1p1    613184    1778"..., 59) = 59
write(1, "tmpfs            2435176      17"..., 64) = 64
close(1)                                = 0
close(2)                                = 0
exit_group(0)                           = ?

And current u-root df version is doing this:

statfs("/sys/kernel/debug/tracing", 0xc000124b08) = -1 EACCES (Permission denied)
openat(AT_FDCWD, "/etc/localtime", O_RDONLY) = 3
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\22\0\0\0\22\0\0\0\0"..., 4096) = 2162
read(3, "", 4096)                       = 0
close(3)                                = 0
write(2, "2023/11/27 07:06:16 mountinfo()="..., 672023/11/27 07:06:16 mountinfo()=_,"permission denied", want: _,nil
) = 67
exit_group(1)                           = ?