diff options
Diffstat (limited to 'libnetdata/simple_pattern')
| -rw-r--r-- | libnetdata/simple_pattern/Makefile.am | 8 | ||||
| -rw-r--r-- | libnetdata/simple_pattern/README.md | 43 | ||||
| -rw-r--r-- | libnetdata/simple_pattern/simple_pattern.c | 365 | ||||
| -rw-r--r-- | libnetdata/simple_pattern/simple_pattern.h | 40 |
4 files changed, 456 insertions, 0 deletions
diff --git a/libnetdata/simple_pattern/Makefile.am b/libnetdata/simple_pattern/Makefile.am new file mode 100644 index 0000000..161784b --- /dev/null +++ b/libnetdata/simple_pattern/Makefile.am @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-3.0-or-later + +AUTOMAKE_OPTIONS = subdir-objects +MAINTAINERCLEANFILES = $(srcdir)/Makefile.in + +dist_noinst_DATA = \ + README.md \ + $(NULL) diff --git a/libnetdata/simple_pattern/README.md b/libnetdata/simple_pattern/README.md new file mode 100644 index 0000000..a90759c --- /dev/null +++ b/libnetdata/simple_pattern/README.md @@ -0,0 +1,43 @@ +<!-- +title: "Netdata simple patterns" +description: "Netdata supports simple patterns, which are less cryptic versions of regular expressions. Use familiar notation for powerful results." +custom_edit_url: https://github.com/netdata/netdata/edit/master/libnetdata/simple_pattern/README.md +--> + +# Netdata simple patterns + +Unix prefers regular expressions. But they are just too hard, too cryptic +to use, write and understand. + +So, Netdata supports **simple patterns**. + +Simple patterns are a space separated list of words, that can have `*` +as a wildcard. Each world may use any number of `*`. Simple patterns +allow **negative** matches by prefixing a word with `!`. + +So, `pattern = !*bad* *` will match anything, except all those that +contain the word `bad`. + +Simple patterns are quite powerful: `pattern = *foobar* !foo* !*bar *` +matches everything containing `foobar`, except strings that start +with `foo` or end with `bar`. + +You can use the Netdata command line to check simple patterns, +like this: + +```sh +# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world' +RESULT: MATCHED - pattern '*foobar* !foo* !*bar *' matches 'hello world' + +# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world bar' +RESULT: NOT MATCHED - pattern '*foobar* !foo* !*bar *' does not match 'hello world bar' + +# netdata -W simple-pattern '*foobar* !foo* !*bar *' 'hello world foobar' +RESULT: MATCHED - pattern '*foobar* !foo* !*bar *' matches 'hello world foobar' +``` + +Netdata stops processing to the first positive or negative match +(left to right). If it is not matched by either positive or negative +patterns, it is denied at the end. + +[](<>) diff --git a/libnetdata/simple_pattern/simple_pattern.c b/libnetdata/simple_pattern/simple_pattern.c new file mode 100644 index 0000000..70b06a2 --- /dev/null +++ b/libnetdata/simple_pattern/simple_pattern.c @@ -0,0 +1,365 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "../libnetdata.h" + +struct simple_pattern { + const char *match; + size_t len; + + SIMPLE_PREFIX_MODE mode; + char negative; + + struct simple_pattern *child; + + struct simple_pattern *next; +}; + +static inline struct simple_pattern *parse_pattern(char *str, SIMPLE_PREFIX_MODE default_mode) { + // fprintf(stderr, "PARSING PATTERN: '%s'\n", str); + + SIMPLE_PREFIX_MODE mode; + struct simple_pattern *child = NULL; + + char *s = str, *c = str; + + // skip asterisks in front + while(*c == '*') c++; + + // find the next asterisk + while(*c && *c != '*') c++; + + // do we have an asterisk in the middle? + if(*c == '*' && c[1] != '\0') { + // yes, we have + child = parse_pattern(c, default_mode); + c[1] = '\0'; + } + + // check what this one matches + + size_t len = strlen(s); + if(len >= 2 && *s == '*' && s[len - 1] == '*') { + s[len - 1] = '\0'; + s++; + mode = SIMPLE_PATTERN_SUBSTRING; + } + else if(len >= 1 && *s == '*') { + s++; + mode = SIMPLE_PATTERN_SUFFIX; + } + else if(len >= 1 && s[len - 1] == '*') { + s[len - 1] = '\0'; + mode = SIMPLE_PATTERN_PREFIX; + } + else + mode = default_mode; + + // allocate the structure + struct simple_pattern *m = callocz(1, sizeof(struct simple_pattern)); + if(*s) { + m->match = strdupz(s); + m->len = strlen(m->match); + m->mode = mode; + } + else { + m->mode = SIMPLE_PATTERN_SUBSTRING; + } + + m->child = child; + + return m; +} + +SIMPLE_PATTERN *simple_pattern_create(const char *list, const char *separators, SIMPLE_PREFIX_MODE default_mode) { + struct simple_pattern *root = NULL, *last = NULL; + + if(unlikely(!list || !*list)) return root; + + int isseparator[256] = { + [' '] = 1 // space + , ['\t'] = 1 // tab + , ['\r'] = 1 // carriage return + , ['\n'] = 1 // new line + , ['\f'] = 1 // form feed + , ['\v'] = 1 // vertical tab + }; + + if (unlikely(separators && *separators)) { + memset(&isseparator[0], 0, sizeof(isseparator)); + while(*separators) isseparator[(unsigned char)*separators++] = 1; + } + + char *buf = mallocz(strlen(list) + 1); + const char *s = list; + + while(s && *s) { + buf[0] = '\0'; + char *c = buf; + + char negative = 0; + + // skip all spaces + while(isseparator[(unsigned char)*s]) + s++; + + if(*s == '!') { + negative = 1; + s++; + } + + // empty string + if(unlikely(!*s)) + break; + + // find the next space + char escape = 0; + while(*s) { + if(*s == '\\' && !escape) { + escape = 1; + s++; + } + else { + if (isseparator[(unsigned char)*s] && !escape) { + s++; + break; + } + + *c++ = *s++; + escape = 0; + } + } + + // terminate our string + *c = '\0'; + + // if we matched the empty string, skip it + if(unlikely(!*buf)) + continue; + + // fprintf(stderr, "FOUND PATTERN: '%s'\n", buf); + struct simple_pattern *m = parse_pattern(buf, default_mode); + m->negative = negative; + + // link it at the end + if(unlikely(!root)) + root = last = m; + else { + last->next = m; + last = m; + } + } + + freez(buf); + return (SIMPLE_PATTERN *)root; +} + +static inline char *add_wildcarded(const char *matched, size_t matched_size, char *wildcarded, size_t *wildcarded_size) { + //if(matched_size) { + // char buf[matched_size + 1]; + // strncpyz(buf, matched, matched_size); + // fprintf(stderr, "ADD WILDCARDED '%s' of length %zu\n", buf, matched_size); + //} + + if(unlikely(wildcarded && *wildcarded_size && matched && *matched && matched_size)) { + size_t wss = *wildcarded_size - 1; + size_t len = (matched_size < wss)?matched_size:wss; + if(likely(len)) { + strncpyz(wildcarded, matched, len); + + *wildcarded_size -= len; + return &wildcarded[len]; + } + } + + return wildcarded; +} + +static inline int match_pattern(struct simple_pattern *m, const char *str, size_t len, char *wildcarded, size_t *wildcarded_size) { + char *s; + + if(m->len <= len) { + switch(m->mode) { + case SIMPLE_PATTERN_SUBSTRING: + if(!m->len) return 1; + if((s = strstr(str, m->match))) { + wildcarded = add_wildcarded(str, s - str, wildcarded, wildcarded_size); + if(!m->child) { + wildcarded = add_wildcarded(&s[m->len], len - (&s[m->len] - str), wildcarded, wildcarded_size); + return 1; + } + return match_pattern(m->child, &s[m->len], len - (s - str) - m->len, wildcarded, wildcarded_size); + } + break; + + case SIMPLE_PATTERN_PREFIX: + if(unlikely(strncmp(str, m->match, m->len) == 0)) { + if(!m->child) { + wildcarded = add_wildcarded(&str[m->len], len - m->len, wildcarded, wildcarded_size); + return 1; + } + return match_pattern(m->child, &str[m->len], len - m->len, wildcarded, wildcarded_size); + } + break; + + case SIMPLE_PATTERN_SUFFIX: + if(unlikely(strcmp(&str[len - m->len], m->match) == 0)) { + wildcarded = add_wildcarded(str, len - m->len, wildcarded, wildcarded_size); + if(!m->child) return 1; + return 0; + } + break; + + case SIMPLE_PATTERN_EXACT: + default: + if(unlikely(strcmp(str, m->match) == 0)) { + if(!m->child) return 1; + return 0; + } + break; + } + } + + return 0; +} + +int simple_pattern_matches_extract(SIMPLE_PATTERN *list, const char *str, char *wildcarded, size_t wildcarded_size) { + struct simple_pattern *m, *root = (struct simple_pattern *)list; + + if(unlikely(!root || !str || !*str)) return 0; + + size_t len = strlen(str); + for(m = root; m ; m = m->next) { + char *ws = wildcarded; + size_t wss = wildcarded_size; + if(unlikely(ws)) *ws = '\0'; + + if (match_pattern(m, str, len, ws, &wss)) { + + //if(ws && wss) + // fprintf(stderr, "FINAL WILDCARDED '%s' of length %zu\n", ws, strlen(ws)); + + if (m->negative) return 0; + return 1; + } + } + + return 0; +} + +static inline void free_pattern(struct simple_pattern *m) { + if(!m) return; + + free_pattern(m->child); + free_pattern(m->next); + freez((void *)m->match); + freez(m); +} + +void simple_pattern_free(SIMPLE_PATTERN *list) { + if(!list) return; + + free_pattern(((struct simple_pattern *)list)); +} + +/* Debugging patterns + + This code should be dead - it is useful for debugging but should not be called by production code. + Feel free to comment it out, but please leave it in the file. +*/ +extern void simple_pattern_dump(uint64_t debug_type, SIMPLE_PATTERN *p) +{ + struct simple_pattern *root = (struct simple_pattern *)p; + if(root==NULL) { + debug(debug_type,"dump_pattern(NULL)"); + return; + } + debug(debug_type,"dump_pattern(%p) child=%p next=%p mode=%u match=%s", root, root->child, root->next, root->mode, + root->match); + if(root->child!=NULL) + simple_pattern_dump(debug_type, (SIMPLE_PATTERN*)root->child); + if(root->next!=NULL) + simple_pattern_dump(debug_type, (SIMPLE_PATTERN*)root->next); +} + +/* Heuristic: decide if the pattern could match a DNS name. + + Although this functionality is used directly by socket.c:connection_allowed() it must be in this file + because of the SIMPLE_PATTERN/simple_pattern structure hiding. + Based on RFC952 / RFC1123. We need to decide if the pattern may match a DNS name, or not. For the negative + cases we need to be sure that it can only match an ipv4 or ipv6 address: + * IPv6 addresses contain ':', which are illegal characters in DNS. + * IPv4 addresses cannot contain alpha- characters. + * DNS TLDs must be alphanumeric to distinguish from IPv4. + Some patterns (e.g. "*a*" ) could match multiple cases (i.e. DNS or IPv6). + Some patterns will be awkward (e.g. "192.168.*") as they look like they are intended to match IPv4-only + but could match DNS (i.e. "192.168.com" is a valid name). +*/ +static void scan_is_potential_name(struct simple_pattern *p, int *alpha, int *colon, int *wildcards) +{ + while (p) { + if (p->match) { + if(p->mode == SIMPLE_PATTERN_EXACT && !strcmp("localhost", p->match)) { + p = p->child; + continue; + } + char const *scan = p->match; + while (*scan != 0) { + if ((*scan >= 'a' && *scan <= 'z') || (*scan >= 'A' && *scan <= 'Z')) + *alpha = 1; + if (*scan == ':') + *colon = 1; + scan++; + } + if (p->mode != SIMPLE_PATTERN_EXACT) + *wildcards = 1; + p = p->child; + } + } +} + +extern int simple_pattern_is_potential_name(SIMPLE_PATTERN *p) +{ + int alpha=0, colon=0, wildcards=0; + struct simple_pattern *root = (struct simple_pattern*)p; + while (root != NULL) { + if (root->match != NULL) { + scan_is_potential_name(root, &alpha, &colon, &wildcards); + } + if (root->mode != SIMPLE_PATTERN_EXACT) + wildcards = 1; + root = root->next; + } + return (alpha || wildcards) && !colon; +} + +char *simple_pattern_trim_around_equal(char *src) { + char *store = mallocz(strlen(src) +1); + if(!store) + return NULL; + + char *dst = store; + while (*src) { + if (*src == '=') { + if (*(dst -1) == ' ') + dst--; + + *dst++ = *src++; + if (*src == ' ') + src++; + } + + *dst++ = *src++; + } + *dst = 0x00; + + return store; +} + +char *simple_pattern_iterate(SIMPLE_PATTERN **p) +{ + struct simple_pattern *root = (struct simple_pattern *) *p; + struct simple_pattern **Proot = (struct simple_pattern **)p; + + (*Proot) = (*Proot)->next; + return (char *) root->match; +} diff --git a/libnetdata/simple_pattern/simple_pattern.h b/libnetdata/simple_pattern/simple_pattern.h new file mode 100644 index 0000000..36fbbde --- /dev/null +++ b/libnetdata/simple_pattern/simple_pattern.h @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#ifndef NETDATA_SIMPLE_PATTERN_H +#define NETDATA_SIMPLE_PATTERN_H + +#include "../libnetdata.h" + + +typedef enum { + SIMPLE_PATTERN_EXACT, + SIMPLE_PATTERN_PREFIX, + SIMPLE_PATTERN_SUFFIX, + SIMPLE_PATTERN_SUBSTRING +} SIMPLE_PREFIX_MODE; + +typedef void SIMPLE_PATTERN; + +// create a simple_pattern from the string given +// default_mode is used in cases where EXACT matches, without an asterisk, +// should be considered PREFIX matches. +extern SIMPLE_PATTERN *simple_pattern_create(const char *list, const char *separators, SIMPLE_PREFIX_MODE default_mode); + +// test if string str is matched from the pattern and fill 'wildcarded' with the parts matched by '*' +extern int simple_pattern_matches_extract(SIMPLE_PATTERN *list, const char *str, char *wildcarded, size_t wildcarded_size); + +// test if string str is matched from the pattern +#define simple_pattern_matches(list, str) simple_pattern_matches_extract(list, str, NULL, 0) + +// free a simple_pattern that was created with simple_pattern_create() +// list can be NULL, in which case, this does nothing. +extern void simple_pattern_free(SIMPLE_PATTERN *list); + +extern void simple_pattern_dump(uint64_t debug_type, SIMPLE_PATTERN *p) ; +extern int simple_pattern_is_potential_name(SIMPLE_PATTERN *p) ; +extern char *simple_pattern_iterate(SIMPLE_PATTERN **p); + +//Auxiliary function to create a pattern +char *simple_pattern_trim_around_equal(char *src); + +#endif //NETDATA_SIMPLE_PATTERN_H |