LXR linux/tools/perf/util/comm.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include "comm.h"
   3#include "util.h"
   4#include <errno.h>
   5#include <stdlib.h>
   6#include <stdio.h>
   7#include <string.h>
   8#include <linux/refcount.h>
   9#include "rwsem.h"
  10
  11struct comm_str {
  12        char *str;
  13        struct rb_node rb_node;
  14        refcount_t refcnt;
  15};
  16
  17/* Should perhaps be moved to struct machine */
  18static struct rb_root comm_str_root;
  19static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
  20
  21static struct comm_str *comm_str__get(struct comm_str *cs)
  22{
  23        if (cs)
  24                refcount_inc(&cs->refcnt);
  25        return cs;
  26}
  27
  28static void comm_str__put(struct comm_str *cs)
  29{
  30        if (cs && refcount_dec_and_test(&cs->refcnt)) {
  31                down_write(&comm_str_lock);
  32                rb_erase(&cs->rb_node, &comm_str_root);
  33                up_write(&comm_str_lock);
  34                zfree(&cs->str);
  35                free(cs);
  36        }
  37}
  38
  39static struct comm_str *comm_str__alloc(const char *str)
  40{
  41        struct comm_str *cs;
  42
  43        cs = zalloc(sizeof(*cs));
  44        if (!cs)
  45                return NULL;
  46
  47        cs->str = strdup(str);
  48        if (!cs->str) {
  49                free(cs);
  50                return NULL;
  51        }
  52
  53        refcount_set(&cs->refcnt, 1);
  54
  55        return cs;
  56}
  57
  58static
  59struct comm_str *__comm_str__findnew(const char *str, struct rb_root *root)
  60{
  61        struct rb_node **p = &root->rb_node;
  62        struct rb_node *parent = NULL;
  63        struct comm_str *iter, *new;
  64        int cmp;
  65
  66        while (*p != NULL) {
  67                parent = *p;
  68                iter = rb_entry(parent, struct comm_str, rb_node);
  69
  70                cmp = strcmp(str, iter->str);
  71                if (!cmp)
  72                        return comm_str__get(iter);
  73
  74                if (cmp < 0)
  75                        p = &(*p)->rb_left;
  76                else
  77                        p = &(*p)->rb_right;
  78        }
  79
  80        new = comm_str__alloc(str);
  81        if (!new)
  82                return NULL;
  83
  84        rb_link_node(&new->rb_node, parent, p);
  85        rb_insert_color(&new->rb_node, root);
  86
  87        return new;
  88}
  89
  90static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
  91{
  92        struct comm_str *cs;
  93
  94        down_write(&comm_str_lock);
  95        cs = __comm_str__findnew(str, root);
  96        up_write(&comm_str_lock);
  97
  98        return cs;
  99}
 100
 101struct comm *comm__new(const char *str, u64 timestamp, bool exec)
 102{
 103        struct comm *comm = zalloc(sizeof(*comm));
 104
 105        if (!comm)
 106                return NULL;
 107
 108        comm->start = timestamp;
 109        comm->exec = exec;
 110
 111        comm->comm_str = comm_str__findnew(str, &comm_str_root);
 112        if (!comm->comm_str) {
 113                free(comm);
 114                return NULL;
 115        }
 116
 117        return comm;
 118}
 119
 120int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
 121{
 122        struct comm_str *new, *old = comm->comm_str;
 123
 124        new = comm_str__findnew(str, &comm_str_root);
 125        if (!new)
 126                return -ENOMEM;
 127
 128        comm_str__put(old);
 129        comm->comm_str = new;
 130        comm->start = timestamp;
 131        if (exec)
 132                comm->exec = true;
 133
 134        return 0;
 135}
 136
 137void comm__free(struct comm *comm)
 138{
 139        comm_str__put(comm->comm_str);
 140        free(comm);
 141}
 142
 143const char *comm__str(const struct comm *comm)
 144{
 145        return comm->comm_str->str;
 146}
 147