1 /* 2 * http_etag - HTTP ETag manipulation 3 * 4 * Copyright(c) 2015,2020 Glenn Strauss gstrauss()gluelogic.com All rights reserved 5 * License: BSD 3-clause (same as lighttpd) 6 */ 7 #include "first.h" 8 9 #include "http_etag.h" 10 11 #include <sys/stat.h> 12 #include <string.h> 13 14 #include "algo_md.h" 15 #include "buffer.h" 16 17 int 18 http_etag_matches (const buffer * const etag, const char *s, const int weak_ok) 19 { 20 if ('*' == s[0] && '\0' == s[1]) return 1; 21 if (buffer_string_is_empty(etag)) return 0; 22 23 uint32_t etag_sz = buffer_string_length(etag); 24 const char *etag_ptr = etag->ptr; 25 26 if (etag_ptr[0] == 'W' && etag_ptr[1] == '/') { 27 if (!weak_ok) return 0; 28 etag_ptr += 2; 29 etag_sz -= 2; 30 } 31 32 while (*s) { 33 while (*s == ' ' || *s == '\t' || *s == ',') ++s; 34 if (s[0] == 'W' && s[1] == '/' ? (s+=2, weak_ok) : 1) { 35 if (0 == strncmp(s, etag_ptr, etag_sz) || *s == '*') { 36 s += (*s != '*' ? etag_sz : 1); 37 if (*s == '\0' || *s == ' ' || *s == '\t' || *s == ',') 38 return 1; 39 } 40 } 41 while (*s != '\0' && *s != ',') ++s; 42 } 43 return 0; 44 } 45 46 static void 47 http_etag_remix (buffer * const etag, const char * const str, const uint32_t len) 48 { 49 uint32_t h = dekhash(str, len, len); /*(pass len as initial hash value)*/ 50 uint32_t elen = buffer_string_length(etag); 51 if (elen > 2) /*(expect "..." if set)*/ 52 h = dekhash(etag->ptr+1, elen-2, h); 53 buffer_string_set_length(etag, 1); 54 etag->ptr[0] = '\"'; 55 buffer_append_int(etag, h); 56 buffer_append_string_len(etag, CONST_STR_LEN("\"")); 57 } 58 59 void 60 http_etag_create (buffer * const etag, const struct stat * const st, const int flags) 61 { 62 if (0 == flags) return; 63 64 uint64_t x[4]; 65 uint32_t len = 0; 66 67 if (flags & ETAG_USE_INODE) 68 x[len++] = (uint64_t)st->st_ino; 69 70 if (flags & ETAG_USE_SIZE) 71 x[len++] = (uint64_t)st->st_size; 72 73 if (flags & ETAG_USE_MTIME) { 74 x[len++] = (uint64_t)st->st_mtime; 75 #ifdef st_mtime /* use high-precision timestamp if available */ 76 #if defined(__APPLE__) && defined(__MACH__) 77 x[len++] = (uint64_t)st->st_mtimespec.tv_nsec; 78 #else 79 x[len++] = (uint64_t)st->st_mtim.tv_nsec; 80 #endif 81 #endif 82 } 83 84 buffer_clear(etag); 85 http_etag_remix(etag, (char *)x, len << 3); 86 } 87