Re: [PATCH] tools/vm/slabinfo: indicates the cause of the EACCES error
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From: Vlastimil Babka <hidden>
Date: 2022-11-10 09:41:02
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On 11/8/22 13:47, Rong Tao wrote:
From: Rong Tao <redacted>
If you don't run slabinfo with a superuser, return 0 when read_slab_dir()
reads get_obj_and_str("slabs", &t), because fopen() fails (sometimes
EACCES), causing slabcache() to return directly, without any error during
this time, we should tell the user about the EACCES problem instead of
running successfully($?=0) without any error printing.
For example:
$ ./slabinfo
Permission denied, Try using superuser <== What this submission did
$ sudo ./slabinfo
Name Objects Objsize Space Slabs/Part/Cpu O/S O %Fr %Ef Flg
Acpi-Namespace 5950 48 286.7K 65/0/5 85 0 0 99
Acpi-Operand 13664 72 999.4K 231/0/13 56 0 0 98
...
Signed-off-by: Rong Tao <redacted>Thanks, added to slab.git slab/for-6.2/tools
quoted hunk
--- tools/vm/slabinfo.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/tools/vm/slabinfo.c b/tools/vm/slabinfo.c index 0fffaeedee76..cfaeaea71042 100644 --- a/tools/vm/slabinfo.c +++ b/tools/vm/slabinfo.c@@ -157,9 +157,11 @@ static unsigned long read_obj(const char *name) { FILE *f = fopen(name, "r"); - if (!f) + if (!f) { buffer[0] = 0; - else { + if (errno == EACCES) + fatal("%s, Try using superuser\n", strerror(errno)); + } else { if (!fgets(buffer, sizeof(buffer), f)) buffer[0] = 0; fclose(f);