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Enable iterating all sysctls, even ones with CTLFLAG_SKIP

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Add an "nextnoskip" sysctl that allows for listing of sysctls intended to be
normally skipped for cost reasons.

This makes it so the names/descriptions of those sysctls can be discovered with
sysctl -aN/sysctl -ad/sysctl -at.

It also makes it so children are visited when a node flagged with CTLFLAG_SKIP
is explicitly requested.

The intended use case is to mark the root "kstat" node with CTLFLAG_SKIP so that
the extensive and expensive stats are skipped by default but may still be easily
obtained without having to know them all (which may not even be possible) and
request each one-by-one.

Reviewed by:	jhb
MFC after:	2 weeks
Relnotes:	yes
Sponsored by:	iXsystems, Inc.
Differential Revision:	https://reviews.freebsd.org/D26560
This commit is contained in:
Ryan Moeller 2020-10-05 20:13:22 +00:00
parent ce3e137ca1
commit 92e17803cd
4 changed files with 53 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
sbin/sysctl/sysctl.c
View File

@ -81,7 +81,7 @@ static int Nflag, nflag, oflag, qflag, tflag, Tflag, Wflag, xflag;
static int oidfmt(int *, int, char *, u_int *);
static int parsefile(const char *);
static int parse(const char *, int);
static int show_var(int *, int);
static int show_var(int *, int, bool);
static int sysctl_all(int *oid, int len);
static int name2oid(const char *, int *);
@ -428,13 +428,13 @@ parse(const char *string, int lineno)
if (newvalstr == NULL || dflag) {
if ((kind & CTLTYPE) == CTLTYPE_NODE) {
if (dflag) {
i = show_var(mib, len);
i = show_var(mib, len, false);
if (!i && !bflag)
putchar('\n');
}
sysctl_all(mib, len);
} else {
i = show_var(mib, len);
i = show_var(mib, len, false);
if (!i && !bflag)
putchar('\n');
}
@ -504,7 +504,7 @@ parse(const char *string, int lineno)
break;
}
i = show_var(mib, len);
i = show_var(mib, len, false);
if (sysctl(mib, len, 0, 0, newval, newsize) == -1) {
free(newbuf);
if (!i && !bflag)
@ -532,7 +532,7 @@ parse(const char *string, int lineno)
printf(" -> ");
i = nflag;
nflag = 1;
j = show_var(mib, len);
j = show_var(mib, len, false);
if (!j && !bflag)
putchar('\n');
nflag = i;
@ -942,7 +942,7 @@ oidfmt(int *oid, int len, char *fmt, u_int *kind)
* Return minus one if we had errors.
*/
static int
show_var(int *oid, int nlen)
show_var(int *oid, int nlen, bool honor_skip)
{
u_char buf[BUFSIZ], *val, *oval, *p;
char name[BUFSIZ], fmt[BUFSIZ];
@ -976,11 +976,11 @@ show_var(int *oid, int nlen)
oidfmt(oid, nlen, fmt, &kind);
/* if Wflag then only list sysctls that are writeable and not stats. */
if (Wflag && ((kind & CTLFLAG_WR) == 0 || (kind & CTLFLAG_STATS) != 0))
return 1;
return (1);
/* if Tflag then only list sysctls that are tuneables. */
if (Tflag && (kind & CTLFLAG_TUN) == 0)
return 1;
return (1);
if (Nflag) {
printf("%s", name);
@ -1013,6 +1013,10 @@ show_var(int *oid, int nlen)
return (0);
}
/* bail before fetching the value if we're honoring skip */
if (honor_skip && (kind & CTLFLAG_SKIP) != 0)
return (1);
/* don't fetch opaques that we don't know how to print */
if (ctltype == CTLTYPE_OPAQUE) {
if (strcmp(fmt, "S,clockinfo") == 0)
@ -1195,15 +1199,17 @@ sysctl_all(int *oid, int len)
int name1[22], name2[22];
int i, j;
size_t l1, l2;
bool honor_skip = false;
name1[0] = 0;
name1[1] = 2;
name1[0] = CTL_SYSCTL;
name1[1] = (oid != NULL || Nflag || dflag || tflag) ?
CTL_SYSCTL_NEXTNOSKIP : CTL_SYSCTL_NEXT;
l1 = 2;
if (len) {
memcpy(name1+2, oid, len * sizeof(int));
memcpy(name1 + 2, oid, len * sizeof(int));
l1 += len;
} else {
name1[2] = 1;
name1[2] = CTL_KERN;
l1++;
}
for (;;) {
@ -1225,11 +1231,12 @@ sysctl_all(int *oid, int len)
if (name2[i] != oid[i])
return (0);
i = show_var(name2, l2);
i = show_var(name2, l2, honor_skip);
if (!i && !bflag)
putchar('\n');
memcpy(name1+2, name2, l2 * sizeof(int));
memcpy(name1 + 2, name2, l2 * sizeof(int));
l1 = 2 + l2;
honor_skip = true;
}
}

44
sys/kern/kern_sysctl.c
View File

@ -950,7 +950,8 @@ SYSINIT(sysctl, SI_SUB_KMEM, SI_ORDER_FIRST, sysctl_register_all, NULL);
* {CTL_SYSCTL, CTL_SYSCTL_DEBUG} printf the entire MIB-tree.
* {CTL_SYSCTL, CTL_SYSCTL_NAME, ...} return the name of the "..."
* OID.
* {CTL_SYSCTL, CTL_SYSCTL_NEXT, ...} return the next OID.
* {CTL_SYSCTL, CTL_SYSCTL_NEXT, ...} return the next OID, honoring
* CTLFLAG_SKIP.
* {CTL_SYSCTL, CTL_SYSCTL_NAME2OID} return the OID of the name in
* "new"
* {CTL_SYSCTL, CTL_SYSCTL_OIDFMT, ...} return the kind & format info
@ -959,6 +960,8 @@ SYSINIT(sysctl, SI_SUB_KMEM, SI_ORDER_FIRST, sysctl_register_all, NULL);
* "..." OID.
* {CTL_SYSCTL, CTL_SYSCTL_OIDLABEL, ...} return the aggregation label of
* the "..." OID.
* {CTL_SYSCTL, CTL_SYSCTL_NEXTNOSKIP, ...} return the next OID, ignoring
* CTLFLAG_SKIP.
*/
#ifdef SYSCTL_DEBUG
@ -1099,7 +1102,7 @@ static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NAME, name, CTLFLAG_RD |
static int
sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
int *next, int *len, int level, struct sysctl_oid **oidpp)
int *next, int *len, int level, struct sysctl_oid **oidpp, bool honor_skip)
{
struct sysctl_oid *oidp;
@ -1109,7 +1112,10 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
*next = oidp->oid_number;
*oidpp = oidp;
if ((oidp->oid_kind & (CTLFLAG_SKIP | CTLFLAG_DORMANT)) != 0)
if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0)
continue;
if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0)
continue;
if (!namelen) {
@ -1120,7 +1126,7 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
return (0);
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, 0, 0, next+1,
len, level+1, oidpp))
len, level+1, oidpp, honor_skip))
return (0);
goto emptynode;
}
@ -1135,7 +1141,7 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
return (0);
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1,
next+1, len, level+1, oidpp))
next+1, len, level+1, oidpp, honor_skip))
return (0);
goto next;
}
@ -1147,14 +1153,14 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
lsp = SYSCTL_CHILDREN(oidp);
if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, next+1,
len, level+1, oidpp))
len, level+1, oidpp, honor_skip))
return (0);
next:
namelen = 1;
emptynode:
*len = level;
}
return (1);
return (ENOENT);
}
static int
@ -1162,18 +1168,19 @@ sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
{
int *name = (int *) arg1;
u_int namelen = arg2;
int i, j, error;
int len, error;
struct sysctl_oid *oid;
struct sysctl_oid_list *lsp = &sysctl__children;
struct rm_priotracker tracker;
int newoid[CTL_MAXNAME];
int next[CTL_MAXNAME];
SYSCTL_RLOCK(&tracker);
i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
error = sysctl_sysctl_next_ls(lsp, name, namelen, next, &len, 1, &oid,
oidp->oid_number == CTL_SYSCTL_NEXT);
SYSCTL_RUNLOCK(&tracker);
if (i)
return (ENOENT);
error = SYSCTL_OUT(req, newoid, j * sizeof (int));
if (error)
return (error);
error = SYSCTL_OUT(req, next, len * sizeof (int));
return (error);
}
@ -1184,6 +1191,9 @@ sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NEXT, next, CTLFLAG_RD |
CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_next, "");
static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NEXTNOSKIP, nextnoskip, CTLFLAG_RD |
CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_next, "");
static int
name2oid(char *name, int *oid, int *len, struct sysctl_oid **oidpp)
{
@ -2726,10 +2736,10 @@ db_show_sysctl_all(int *oid, size_t len, int flags)
name1[1] = CTL_SYSCTL_NEXT;
l1 = 2;
if (len) {
memcpy(name1+2, oid, len * sizeof(int));
l1 +=len;
memcpy(name1 + 2, oid, len * sizeof(int));
l1 += len;
} else {
name1[2] = 1;
name1[2] = CTL_KERN;
l1++;
}
for (;;) {
@ -2742,7 +2752,7 @@ db_show_sysctl_all(int *oid, size_t len, int flags)
if (error == ENOENT)
return (0);
else
db_error("sysctl(getnext)");
db_error("sysctl(next)");
}
l2 /= sizeof(int);

3
sys/sys/sysctl.h
View File

@ -934,11 +934,12 @@ TAILQ_HEAD(sysctl_ctx_list, sysctl_ctx_entry);
*/
#define CTL_SYSCTL_DEBUG 0 /* printf all nodes */
#define CTL_SYSCTL_NAME 1 /* string name of OID */
#define CTL_SYSCTL_NEXT 2 /* next OID */
#define CTL_SYSCTL_NEXT 2 /* next OID, honoring CTLFLAG_SKIP */
#define CTL_SYSCTL_NAME2OID 3 /* int array of name */
#define CTL_SYSCTL_OIDFMT 4 /* OID's kind and format */
#define CTL_SYSCTL_OIDDESCR 5 /* OID's description */
#define CTL_SYSCTL_OIDLABEL 6 /* aggregation label */
#define CTL_SYSCTL_NEXTNOSKIP 7 /* next OID, ignoring CTLFLAG_SKIP */
/*
* CTL_KERN identifiers

3
usr.bin/truss/syscalls.c
View File

@ -2360,6 +2360,9 @@ print_arg(struct syscall_args *sc, unsigned long *args, register_t *retval,
fprintf(fp, "oidlabel ");
print_sysctl(fp, oid + 2, len - 2);
break;
case CTL_SYSCTL_NEXTNOSKIP:
fprintf(fp, "nextnoskip");
break;
default:
print_sysctl(fp, oid + 1, len - 1);
}