153 lines
2.8 KiB
C
153 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "comm.h"
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#include "util.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <linux/refcount.h>
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#include "rwsem.h"
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struct comm_str {
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char *str;
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struct rb_node rb_node;
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refcount_t refcnt;
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};
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/* Should perhaps be moved to struct machine */
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static struct rb_root comm_str_root;
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static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
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static struct comm_str *comm_str__get(struct comm_str *cs)
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{
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if (cs && refcount_inc_not_zero(&cs->refcnt))
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return cs;
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return NULL;
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}
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static void comm_str__put(struct comm_str *cs)
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{
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if (cs && refcount_dec_and_test(&cs->refcnt)) {
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down_write(&comm_str_lock);
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rb_erase(&cs->rb_node, &comm_str_root);
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up_write(&comm_str_lock);
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zfree(&cs->str);
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free(cs);
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}
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}
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static struct comm_str *comm_str__alloc(const char *str)
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{
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struct comm_str *cs;
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cs = zalloc(sizeof(*cs));
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if (!cs)
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return NULL;
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cs->str = strdup(str);
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if (!cs->str) {
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free(cs);
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return NULL;
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}
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refcount_set(&cs->refcnt, 1);
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return cs;
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}
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static
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struct comm_str *__comm_str__findnew(const char *str, struct rb_root *root)
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{
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struct rb_node **p = &root->rb_node;
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struct rb_node *parent = NULL;
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struct comm_str *iter, *new;
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int cmp;
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while (*p != NULL) {
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parent = *p;
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iter = rb_entry(parent, struct comm_str, rb_node);
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/*
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* If we race with comm_str__put, iter->refcnt is 0
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* and it will be removed within comm_str__put call
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* shortly, ignore it in this search.
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*/
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cmp = strcmp(str, iter->str);
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if (!cmp && comm_str__get(iter))
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return iter;
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if (cmp < 0)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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new = comm_str__alloc(str);
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if (!new)
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return NULL;
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rb_link_node(&new->rb_node, parent, p);
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rb_insert_color(&new->rb_node, root);
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return new;
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}
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static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
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{
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struct comm_str *cs;
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down_write(&comm_str_lock);
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cs = __comm_str__findnew(str, root);
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up_write(&comm_str_lock);
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return cs;
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}
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struct comm *comm__new(const char *str, u64 timestamp, bool exec)
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{
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struct comm *comm = zalloc(sizeof(*comm));
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if (!comm)
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return NULL;
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comm->start = timestamp;
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comm->exec = exec;
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comm->comm_str = comm_str__findnew(str, &comm_str_root);
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if (!comm->comm_str) {
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free(comm);
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return NULL;
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}
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return comm;
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}
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int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
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{
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struct comm_str *new, *old = comm->comm_str;
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new = comm_str__findnew(str, &comm_str_root);
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if (!new)
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return -ENOMEM;
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comm_str__put(old);
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comm->comm_str = new;
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comm->start = timestamp;
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if (exec)
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comm->exec = true;
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return 0;
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}
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void comm__free(struct comm *comm)
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{
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comm_str__put(comm->comm_str);
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free(comm);
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}
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const char *comm__str(const struct comm *comm)
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{
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return comm->comm_str->str;
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}
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