tools/perf/util/strfilter.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "string2.h"
   3 #include "strfilter.h"
   4
   5 #include <errno.h>
   6 #include <stdlib.h>
   7 #include <linux/ctype.h>
   8 #include <linux/string.h>
   9 #include <linux/zalloc.h>
  10
  11 /* Operators */
  12 static const char *OP_and       = "&";  /* Logical AND */
  13 static const char *OP_or        = "|";  /* Logical OR */
  14 static const char *OP_not       = "!";  /* Logical NOT */
  15
  16 #define is_operator(c)  ((c) == '|' || (c) == '&' || (c) == '!')
  17 #define is_separator(c) (is_operator(c) || (c) == '(' || (c) == ')')
  18
  19 static void strfilter_node__delete(struct strfilter_node *node)
  20 {
  21         if (node) {
  22                 if (node->p && !is_operator(*node->p))
  23                         zfree((char **)&node->p);
  24                 strfilter_node__delete(node->l);
  25                 strfilter_node__delete(node->r);
  26                 free(node);
  27         }
  28 }
  29
  30 void strfilter__delete(struct strfilter *filter)
  31 {
  32         if (filter) {
  33                 strfilter_node__delete(filter->root);
  34                 free(filter);
  35         }
  36 }
  37
  38 static const char *get_token(const char *s, const char **e)
  39 {
  40         const char *p;
  41
  42         s = skip_spaces(s);
  43
  44         if (*s == '\0') {
  45                 p = s;
  46                 goto end;
  47         }
  48
  49         p = s + 1;
  50         if (!is_separator(*s)) {
  51                 /* End search */
  52 retry:
  53                 while (*p && !is_separator(*p) && !isspace(*p))
  54                         p++;
  55                 /* Escape and special case: '!' is also used in glob pattern */
  56                 if (*(p - 1) == '\\' || (*p == '!' && *(p - 1) == '[')) {
  57                         p++;
  58                         goto retry;
  59                 }
  60         }
  61 end:
  62         *e = p;
  63         return s;
  64 }
  65
  66 static struct strfilter_node *strfilter_node__alloc(const char *op,
  67                                                     struct strfilter_node *l,
  68                                                     struct strfilter_node *r)
  69 {
  70         struct strfilter_node *node = zalloc(sizeof(*node));
  71
  72         if (node) {
  73                 node->p = op;
  74                 node->l = l;
  75                 node->r = r;
  76         }
  77
  78         return node;
  79 }
  80
  81 static struct strfilter_node *strfilter_node__new(const char *s,
  82                                                   const char **ep)
  83 {
  84         struct strfilter_node root, *cur, *last_op;
  85         const char *e;
  86
  87         if (!s)
  88                 return NULL;
  89
  90         memset(&root, 0, sizeof(root));
  91         last_op = cur = &root;
  92
  93         s = get_token(s, &e);
  94         while (*s != '\0' && *s != ')') {
  95                 switch (*s) {
  96                 case '&':       /* Exchg last OP->r with AND */
  97                         if (!cur->r || !last_op->r)
  98                                 goto error;
  99                         cur = strfilter_node__alloc(OP_and, last_op->r, NULL);
 100                         if (!cur)
 101                                 goto nomem;
 102                         last_op->r = cur;
 103                         last_op = cur;
 104                         break;
 105                 case '|':       /* Exchg the root with OR */
 106                         if (!cur->r || !root.r)
 107                                 goto error;
 108                         cur = strfilter_node__alloc(OP_or, root.r, NULL);
 109                         if (!cur)
 110                                 goto nomem;
 111                         root.r = cur;
 112                         last_op = cur;
 113                         break;
 114                 case '!':       /* Add NOT as a leaf node */
 115                         if (cur->r)
 116                                 goto error;
 117                         cur->r = strfilter_node__alloc(OP_not, NULL, NULL);
 118                         if (!cur->r)
 119                                 goto nomem;
 120                         cur = cur->r;
 121                         break;
 122                 case '(':       /* Recursively parses inside the parenthesis */
 123                         if (cur->r)
 124                                 goto error;
 125                         cur->r = strfilter_node__new(s + 1, &s);
 126                         if (!s)
 127                                 goto nomem;
 128                         if (!cur->r || *s != ')')
 129                                 goto error;
 130                         e = s + 1;
 131                         break;
 132                 default:
 133                         if (cur->r)
 134                                 goto error;
 135                         cur->r = strfilter_node__alloc(NULL, NULL, NULL);
 136                         if (!cur->r)
 137                                 goto nomem;
 138                         cur->r->p = strndup(s, e - s);
 139                         if (!cur->r->p)
 140                                 goto nomem;
 141                 }
 142                 s = get_token(e, &e);
 143         }
 144         if (!cur->r)
 145                 goto error;
 146         *ep = s;
 147         return root.r;
 148 nomem:
 149         s = NULL;
 150 error:
 151         *ep = s;
 152         strfilter_node__delete(root.r);
 153         return NULL;
 154 }
 155
 156 /*
 157  * Parse filter rule and return new strfilter.
 158  * Return NULL if fail, and *ep == NULL if memory allocation failed.
 159  */
 160 struct strfilter *strfilter__new(const char *rules, const char **err)
 161 {
 162         struct strfilter *filter = zalloc(sizeof(*filter));
 163         const char *ep = NULL;
 164
 165         if (filter)
 166                 filter->root = strfilter_node__new(rules, &ep);
 167
 168         if (!filter || !filter->root || *ep != '\0') {
 169                 if (err)
 170                         *err = ep;
 171                 strfilter__delete(filter);
 172                 filter = NULL;
 173         }
 174
 175         return filter;
 176 }
 177
 178 static int strfilter__append(struct strfilter *filter, bool _or,
 179                              const char *rules, const char **err)
 180 {
 181         struct strfilter_node *right, *root;
 182         const char *ep = NULL;
 183
 184         if (!filter || !rules)
 185                 return -EINVAL;
 186
 187         right = strfilter_node__new(rules, &ep);
 188         if (!right || *ep != '\0') {
 189                 if (err)
 190                         *err = ep;
 191                 goto error;
 192         }
 193         root = strfilter_node__alloc(_or ? OP_or : OP_and, filter->root, right);
 194         if (!root) {
 195                 ep = NULL;
 196                 goto error;
 197         }
 198
 199         filter->root = root;
 200         return 0;
 201
 202 error:
 203         strfilter_node__delete(right);
 204         return ep ? -EINVAL : -ENOMEM;
 205 }
 206
 207 int strfilter__or(struct strfilter *filter, const char *rules, const char **err)
 208 {
 209         return strfilter__append(filter, true, rules, err);
 210 }
 211
 212 int strfilter__and(struct strfilter *filter, const char *rules,
 213                    const char **err)
 214 {
 215         return strfilter__append(filter, false, rules, err);
 216 }
 217
 218 static bool strfilter_node__compare(struct strfilter_node *node,
 219                                     const char *str)
 220 {
 221         if (!node || !node->p)
 222                 return false;
 223
 224         switch (*node->p) {
 225         case '|':       /* OR */
 226                 return strfilter_node__compare(node->l, str) ||
 227                         strfilter_node__compare(node->r, str);
 228         case '&':       /* AND */
 229                 return strfilter_node__compare(node->l, str) &&
 230                         strfilter_node__compare(node->r, str);
 231         case '!':       /* NOT */
 232                 return !strfilter_node__compare(node->r, str);
 233         default:
 234                 return strglobmatch(str, node->p);
 235         }
 236 }
 237
 238 /* Return true if STR matches the filter rules */
 239 bool strfilter__compare(struct strfilter *filter, const char *str)
 240 {
 241         if (!filter)
 242                 return false;
 243         return strfilter_node__compare(filter->root, str);
 244 }
 245
 246 static int strfilter_node__sprint(struct strfilter_node *node, char *buf);
 247
 248 /* sprint node in parenthesis if needed */
 249 static int strfilter_node__sprint_pt(struct strfilter_node *node, char *buf)
 250 {
 251         int len;
 252         int pt = node->r ? 2 : 0;       /* don't need to check node->l */
 253
 254         if (buf && pt)
 255                 *buf++ = '(';
 256         len = strfilter_node__sprint(node, buf);
 257         if (len < 0)
 258                 return len;
 259         if (buf && pt)
 260                 *(buf + len) = ')';
 261         return len + pt;
 262 }
 263
 264 static int strfilter_node__sprint(struct strfilter_node *node, char *buf)
 265 {
 266         int len = 0, rlen;
 267
 268         if (!node || !node->p)
 269                 return -EINVAL;
 270
 271         switch (*node->p) {
 272         case '|':
 273         case '&':
 274                 len = strfilter_node__sprint_pt(node->l, buf);
 275                 if (len < 0)
 276                         return len;
 277                 __fallthrough;
 278         case '!':
 279                 if (buf) {
 280                         *(buf + len++) = *node->p;
 281                         buf += len;
 282                 } else
 283                         len++;
 284                 rlen = strfilter_node__sprint_pt(node->r, buf);
 285                 if (rlen < 0)
 286                         return rlen;
 287                 len += rlen;
 288                 break;
 289         default:
 290                 len = strlen(node->p);
 291                 if (buf)
 292                         strcpy(buf, node->p);
 293         }
 294
 295         return len;
 296 }
 297
 298 char *strfilter__string(struct strfilter *filter)
 299 {
 300         int len;
 301         char *ret = NULL;
 302
 303         len = strfilter_node__sprint(filter->root, NULL);
 304         if (len < 0)
 305                 return NULL;
 306
 307         ret = malloc(len + 1);
 308         if (ret)
 309                 strfilter_node__sprint(filter->root, ret);
 310
 311         return ret;
 312 }