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
  11 struct 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 */
  18 static struct rb_root comm_str_root;
  19 static struct rw_semaphore comm_str_lock = {.lock = PTHREAD_RWLOCK_INITIALIZER,};
  20
  21 static struct comm_str *comm_str__get(struct comm_str *cs)
  22 {
  23         if (cs)
  24                 refcount_inc(&cs->refcnt);
  25         return cs;
  26 }
  27
  28 static 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
  39 static 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
  58 static
  59 struct 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
  90 static 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
 101 struct 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
 120 int 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
 137 void comm__free(struct comm *comm)
 138 {
 139         comm_str__put(comm->comm_str);
 140         free(comm);
 141 }
 142
 143 const char *comm__str(const struct comm *comm)
 144 {
 145         return comm->comm_str->str;
 146 }