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Move inner loop logic out of sysctl_sysctl_next_ls().
Refactor sysctl_sysctl_next_ls(): * Move huge inner loop out of sysctl_sysctl_next_ls() into a separate non-recursive function, returning the next step to be taken. * Update resulting node oid parts only on successful lookup * Make sysctl_sysctl_next_ls() return boolean success/failure instead of errno, slightly simplifying logic Reviewed by: freqlabs Differential Revision: https://reviews.freebsd.org/D27029
This commit is contained in:
parent
77df2c21cb
commit
8db8bebf1f
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=368199
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@ -1100,109 +1100,148 @@ sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
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static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NAME, name, CTLFLAG_RD |
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CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_name, "");
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enum sysctl_iter_action {
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ITER_SIBLINGS, /* Not matched, continue iterating siblings */
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ITER_CHILDREN, /* Node has children we need to iterate over them */
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ITER_FOUND, /* Matching node was found */
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};
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/*
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* Walk the sysctl subtree at lsp until we find the given name,
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* and return the next name in order by oid_number.
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* Tries to find the next node for @name and @namelen.
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*
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* Returns next action to take.
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*/
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static int
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sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
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static enum sysctl_iter_action
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sysctl_sysctl_next_node(struct sysctl_oid *oidp, int *name, unsigned int namelen,
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bool honor_skip)
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{
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if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0)
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return (ITER_SIBLINGS);
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if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0)
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return (ITER_SIBLINGS);
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if (namelen == 0) {
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/*
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* We have reached a node with a full name match and are
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* looking for the next oid in its children.
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*
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* For CTL_SYSCTL_NEXTNOSKIP we are done.
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*
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* For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
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* has a handler) and move on to the children.
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*/
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if (!honor_skip)
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return (ITER_FOUND);
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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return (ITER_FOUND);
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/* If node does not have an iterator, treat it as leaf */
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if (oidp->oid_handler)
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return (ITER_FOUND);
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/* Report oid as a node to iterate */
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return (ITER_CHILDREN);
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}
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/*
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* No match yet. Continue seeking the given name.
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*
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* We are iterating in order by oid_number, so skip oids lower
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* than the one we are looking for.
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*
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* When the current oid_number is higher than the one we seek,
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* that means we have reached the next oid in the sequence and
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* should return it.
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*
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* If the oid_number matches the name at this level then we
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* have to find a node to continue searching at the next level.
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*/
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if (oidp->oid_number < *name)
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return (ITER_SIBLINGS);
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if (oidp->oid_number > *name) {
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/*
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* We have reached the next oid.
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*
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* For CTL_SYSCTL_NEXTNOSKIP we are done.
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*
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* For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
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* has a handler) and move on to the children.
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*/
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if (!honor_skip)
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return (ITER_FOUND);
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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return (ITER_FOUND);
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/* If node does not have an iterator, treat it as leaf */
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if (oidp->oid_handler)
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return (ITER_FOUND);
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return (ITER_CHILDREN);
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}
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/* match at a current level */
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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return (ITER_SIBLINGS);
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if (oidp->oid_handler)
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return (ITER_SIBLINGS);
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return (ITER_CHILDREN);
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}
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/*
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* Recursively walk the sysctl subtree at lsp until we find the given name.
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* Returns true and fills in next oid data in @next and @len if oid is found.
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*/
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static bool
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sysctl_sysctl_next_action(struct sysctl_oid_list *lsp, int *name, u_int namelen,
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int *next, int *len, int level, bool honor_skip)
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{
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struct sysctl_oid *oidp;
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bool success = false;
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enum sysctl_iter_action action;
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SYSCTL_ASSERT_LOCKED();
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*len = level;
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SLIST_FOREACH(oidp, lsp, oid_link) {
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*next = oidp->oid_number;
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if ((oidp->oid_kind & CTLFLAG_DORMANT) != 0)
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action = sysctl_sysctl_next_node(oidp, name, namelen, honor_skip);
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if (action == ITER_SIBLINGS)
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continue;
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if (honor_skip && (oidp->oid_kind & CTLFLAG_SKIP) != 0)
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continue;
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if (namelen == 0) {
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/*
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* We have reached a node with a full name match and are
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* looking for the next oid in its children.
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*
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* For CTL_SYSCTL_NEXTNOSKIP we are done.
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*
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* For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
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* has a handler) and move on to the children.
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*/
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if (!honor_skip)
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return (0);
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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return (0);
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if (oidp->oid_handler)
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return (0);
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lsp = SYSCTL_CHILDREN(oidp);
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if (!sysctl_sysctl_next_ls(lsp, NULL, 0, next + 1, len,
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level + 1, honor_skip))
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return (0);
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/*
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* There were no useable children in this node.
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* Continue searching for the next oid at this level.
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*/
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goto emptynode;
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if (action == ITER_FOUND) {
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success = true;
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break;
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}
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KASSERT((action== ITER_CHILDREN), ("ret(%d)!=ITER_CHILDREN", action));
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/*
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* No match yet. Continue seeking the given name.
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*
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* We are iterating in order by oid_number, so skip oids lower
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* than the one we are looking for.
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*
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* When the current oid_number is higher than the one we seek,
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* that means we have reached the next oid in the sequence and
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* should return it.
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*
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* If the oid_number matches the name at this level then we
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* have to find a node to continue searching at the next level.
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*/
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if (oidp->oid_number < *name)
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continue;
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if (oidp->oid_number > *name) {
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/*
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* We have reached the next oid.
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*
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* For CTL_SYSCTL_NEXTNOSKIP we are done.
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*
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* For CTL_SYSCTL_NEXT we skip CTLTYPE_NODE (unless it
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* has a handler) and move on to the children.
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*/
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if (!honor_skip)
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return (0);
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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return (0);
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if (oidp->oid_handler)
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return (0);
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lsp = SYSCTL_CHILDREN(oidp);
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if (!sysctl_sysctl_next_ls(lsp, name + 1, namelen - 1,
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next + 1, len, level + 1, honor_skip))
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return (0);
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goto next;
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}
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if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
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continue;
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if (oidp->oid_handler)
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continue;
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lsp = SYSCTL_CHILDREN(oidp);
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if (!sysctl_sysctl_next_ls(lsp, name + 1, namelen - 1,
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next + 1, len, level + 1, honor_skip))
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return (0);
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next:
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/*
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* There were no useable children in this node.
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* Continue searching for the next oid at the root level.
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*/
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namelen = 1;
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emptynode:
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/* Reset len in case a failed recursive call changed it. */
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*len = level;
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if (namelen == 0) {
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success = sysctl_sysctl_next_action(lsp, NULL, 0,
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next + 1, len, level + 1, honor_skip);
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} else {
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success = sysctl_sysctl_next_action(lsp, name + 1, namelen - 1,
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next + 1, len, level + 1, honor_skip);
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if (!success) {
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/*
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* We maintain the invariant that current node oid
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* is >= the oid provided in @name.
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* As there are no usable children at this node,
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* current node oid is strictly > than the requested
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* oid.
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* Hence, reduce namelen to 0 to allow for picking first
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* nodes/leafs in the next node in list.
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*/
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namelen = 0;
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}
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}
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if (success)
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break;
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}
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return (ENOENT);
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if (success) {
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*next = oidp->oid_number;
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if (level > *len)
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*len = level;
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}
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return (success);
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}
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static int
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@ -1211,16 +1250,18 @@ sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
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int *name = (int *) arg1;
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u_int namelen = arg2;
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int len, error;
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bool success;
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struct sysctl_oid_list *lsp = &sysctl__children;
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struct rm_priotracker tracker;
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int next[CTL_MAXNAME];
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len = 0;
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SYSCTL_RLOCK(&tracker);
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error = sysctl_sysctl_next_ls(lsp, name, namelen, next, &len, 1,
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success = sysctl_sysctl_next_action(lsp, name, namelen, next, &len, 1,
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oidp->oid_number == CTL_SYSCTL_NEXT);
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SYSCTL_RUNLOCK(&tracker);
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if (error)
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return (error);
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if (!success)
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return (ENOENT);
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error = SYSCTL_OUT(req, next, len * sizeof (int));
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return (error);
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}
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