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153 lines
2.8 KiB
153 lines
2.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include "comm.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 <linux/rbtree.h> |
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#include <linux/zalloc.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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