1 #include <u.h> 2 #include <libc.h> 3 4 #define TZSIZE 150 5 static void readtimezone(void); 6 static int rd_name(char**, char*); 7 static int rd_long(char**, long*); 8 static 9 struct 10 { 11 char stname[4]; 12 char dlname[4]; 13 long stdiff; 14 long dldiff; 15 long dlpairs[TZSIZE]; 16 } timezone; 17 18 #define SEC2MIN 60L 19 #define SEC2HOUR (60L*SEC2MIN) 20 #define SEC2DAY (24L*SEC2HOUR) 21 22 /* 23 * days per month plus days/year 24 */ 25 static int dmsize[] = 26 { 27 365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 28 }; 29 static int ldmsize[] = 30 { 31 366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 32 }; 33 34 /* 35 * return the days/month for the given year 36 */ 37 static int * 38 yrsize(int y) 39 { 40 if((y%4) == 0 && ((y%100) != 0 || (y%400) == 0)) 41 return ldmsize; 42 else 43 return dmsize; 44 } 45 46 /* 47 * compute seconds since Jan 1 1970 GMT 48 * and convert to our timezone. 49 */ 50 long 51 tm2sec(Tm *tm) 52 { 53 long secs; 54 int i, year, *d2m; 55 56 if(strcmp(tm->zone, "GMT") != 0 && timezone.stname[0] == 0) 57 readtimezone(); 58 secs = 0; 59 60 /* 61 * seconds per year 62 */ 63 year = tm->year + 1900; 64 for(i = 1970; i < year; i++){ 65 d2m = yrsize(i); 66 secs += d2m[0] * SEC2DAY; 67 } 68 69 /* 70 * seconds per month 71 */ 72 d2m = yrsize(year); 73 for(i = 0; i < tm->mon; i++) 74 secs += d2m[i+1] * SEC2DAY; 75 76 /* 77 * secs in last month 78 */ 79 secs += (tm->mday-1) * SEC2DAY; 80 81 /* 82 * hours, minutes, seconds 83 */ 84 secs += tm->hour * SEC2HOUR; 85 secs += tm->min * SEC2MIN; 86 secs += tm->sec; 87 88 /* 89 * Only handles zones mentioned in /env/timezone, 90 * but things get too ambiguous otherwise. 91 */ 92 if(strcmp(tm->zone, timezone.stname) == 0) 93 secs -= timezone.stdiff; 94 else if(strcmp(tm->zone, timezone.dlname) == 0) 95 secs -= timezone.dldiff; 96 if(secs < 0) 97 secs = 0; 98 return secs; 99 } 100 101 static 102 void 103 readtimezone(void) 104 { 105 char buf[TZSIZE*11+30], *p; 106 int i; 107 108 memset(buf, 0, sizeof(buf)); 109 i = open("/env/timezone", 0); 110 if(i < 0) 111 goto error; 112 if(read(i, buf, sizeof(buf)) >= sizeof(buf)) 113 goto error; 114 close(i); 115 p = buf; 116 if(rd_name(&p, timezone.stname)) 117 goto error; 118 if(rd_long(&p, &timezone.stdiff)) 119 goto error; 120 if(rd_name(&p, timezone.dlname)) 121 goto error; 122 if(rd_long(&p, &timezone.dldiff)) 123 goto error; 124 for(i=0; i<TZSIZE; i++) { 125 if(rd_long(&p, &timezone.dlpairs[i])) 126 goto error; 127 if(timezone.dlpairs[i] == 0) 128 return; 129 } 130 131 error: 132 timezone.stdiff = 0; 133 strcpy(timezone.stname, "GMT"); 134 timezone.dlpairs[0] = 0; 135 } 136 137 static int 138 rd_name(char **f, char *p) 139 { 140 int c, i; 141 142 for(;;) { 143 c = *(*f)++; 144 if(c != ' ' && c != '\n') 145 break; 146 } 147 for(i=0; i<3; i++) { 148 if(c == ' ' || c == '\n') 149 return 1; 150 *p++ = c; 151 c = *(*f)++; 152 } 153 if(c != ' ' && c != '\n') 154 return 1; 155 *p = 0; 156 return 0; 157 } 158 159 static int 160 rd_long(char **f, long *p) 161 { 162 int c, s; 163 long l; 164 165 s = 0; 166 for(;;) { 167 c = *(*f)++; 168 if(c == '-') { 169 s++; 170 continue; 171 } 172 if(c != ' ' && c != '\n') 173 break; 174 } 175 if(c == 0) { 176 *p = 0; 177 return 0; 178 } 179 l = 0; 180 for(;;) { 181 if(c == ' ' || c == '\n') 182 break; 183 if(c < '0' || c > '9') 184 return 1; 185 l = l*10 + c-'0'; 186 c = *(*f)++; 187 } 188 if(s) 189 l = -l; 190 *p = l; 191 return 0; 192 } 193