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authorManuel Novoa III <mjn3@codepoet.org>2002-10-28 19:01:15 +0000
committerManuel Novoa III <mjn3@codepoet.org>2002-10-28 19:01:15 +0000
commit6072ec712b72521d7a13a22b6d9ccf6127c8c005 (patch)
tree7ccf1da7cde7e5ff0ba8a9a41a038bb5707731cc
parentfe8cd7e5ad6dc2789cd7a77490926a1495965a7f (diff)
Allow timezone info to be specified in a file... /etc/TZ. Turned on by
default for now. From the comments... * Defining __TIME_TZ_FILE causes tzset() to attempt to read the TZ value * from the file /etc/TZ if the TZ env variable isn't set. The file contents * must be the intended value of TZ, followed by a newline. No other chars, * spacing, etc is allowed. As an example, an easy way for me to init * /etc/TZ appropriately would be: echo CST6CDT > /etc/TZ Also optimized timezone setting when the timezone string hasn't changed, as well as fixed a minor buglet wrt SUSv3-allowed chars in TZ std and dst fields.
-rw-r--r--libc/misc/time/time.c135
1 files changed, 132 insertions, 3 deletions
diff --git a/libc/misc/time/time.c b/libc/misc/time/time.c
index 3f0ddf78d..378854adc 100644
--- a/libc/misc/time/time.c
+++ b/libc/misc/time/time.c
@@ -71,6 +71,28 @@
* TODO - Rework _time_mktime to remove the dependency on long long.
*/
+/* Oct 28, 2002
+ *
+ * Fixed allowed char check for std and dst TZ fields.
+ *
+ * Added several options concerned with timezone support. The names will
+ * probably change once Erik gets the new config system in place.
+ *
+ * Defining __TIME_TZ_FILE causes tzset() to attempt to read the TZ value
+ * from the file /etc/TZ if the TZ env variable isn't set. The file contents
+ * must be the intended value of TZ, followed by a newline. No other chars,
+ * spacing, etc is allowed. As an example, an easy way for me to init
+ * /etc/TZ appropriately would be: echo CST6CDT > /etc/TZ
+ *
+ * Defining __TIME_TZ_FILE_ONCE will cause all further accesses of /etc/TZ
+ * to be skipped once a legal value has been read.
+ *
+ * Defining __TIME_TZ_OPT_SPEED will cause a tzset() to keep a copy of the
+ * last TZ setting string and do a "fast out" if the current string is the
+ * same.
+ */
+
+
#define _GNU_SOURCE
#define _STDIO_UTILITY
#include <stdio.h>
@@ -93,9 +115,30 @@
#define TZNAME_MAX _POSIX_TZNAME_MAX
#endif
+/**********************************************************************/
+
/* The era code is currently unfinished. */
/* #define ENABLE_ERA_CODE */
+#define __TIME_TZ_FILE
+/* #define __TIME_TZ_FILE_ONCE */
+
+#define __TIME_TZ_OPT_SPEED
+
+#define TZ_BUFLEN (2*TZNAME_MAX + 56)
+
+#ifdef __TIME_TZ_FILE
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+/* ":<tzname>+hh:mm:ss<tzname>+hh:mm:ss,Mmm.w.d/hh:mm:ss,Mmm.w.d/hh:mm:ss" + nul */
+/* 1 + 2*(1+TZNAME_MAX+1 + 9 + 7 + 9) + 1 = 2*TZNAME_MAX + 56 */
+#else /* __TIME_TZ_FILE */
+#undef __TIME_TZ_FILE_ONCE
+#endif /* __TIME_TZ_FILE */
+
+/**********************************************************************/
+
extern struct tm __time_tm;
typedef struct {
@@ -1476,6 +1519,50 @@ static const char *getnumber(register const char *e, int *pn)
#endif /* __BCC__ */
}
+#ifdef __TIME_TZ_FILE
+
+#ifdef __TIME_TZ_FILE_ONCE
+static int TZ_file_read; /* Let BSS initialization set this to 0. */
+#endif /* __TIME_TZ_FILE_ONCE */
+
+static char *read_TZ_file(char *buf)
+{
+ int fd;
+ ssize_t r;
+ size_t todo;
+ char *p = NULL;
+
+ if ((fd = open("/etc/TZ", O_RDONLY)) >= 0) {
+ todo = TZ_BUFLEN;
+ p = buf;
+ do {
+ if ((r = read(fd, p, todo)) < 0) {
+ goto ERROR;
+ }
+ if (r == 0) {
+ break;
+ }
+ p += r;
+ todo -= r;
+ } while (todo);
+
+ if ((p > buf) && (p[-1] == '\n')) { /* Must end with newline. */
+ p[-1] = 0;
+ p = buf;
+#ifdef __TIME_TZ_FILE_ONCE
+ ++TZ_file_read;
+#endif /* __TIME_TZ_FILE_ONCE */
+ } else {
+ ERROR:
+ p = NULL;
+ }
+ close(fd);
+ }
+ return p;
+}
+
+#endif /* __TIME_TZ_FILE */
+
void tzset(void)
{
register const char *e;
@@ -1485,11 +1572,42 @@ void tzset(void)
rule_struct new_rules[2];
int n, count, f;
char c;
+#ifdef __TIME_TZ_FILE
+ char buf[TZ_BUFLEN];
+#endif /* __TIME_TZ_FILE */
+#ifdef __TIME_TZ_OPT_SPEED
+ static char oldval[TZ_BUFLEN]; /* BSS-zero'd. */
+#endif /* __TIME_TZ_OPT_SPEED */
TZLOCK;
- if (!(e = getenv(TZ)) || !*e) { /* Not set or set to empty string. */
+ e = getenv(TZ); /* TZ env var always takes precedence. */
+
+#ifdef __TIME_TZ_FILE_ONCE
+ /* Put this inside the lock to prevent the possiblity of two different
+ * timezones being used in a threaded app. */
+
+ if (e != NULL) {
+ TZ_file_read = 0; /* Reset if the TZ env var is set. */
+ } else if (TZ_file_read > 0) {
+ goto FAST_DONE;
+ }
+#endif /* __TIME_TZ_FILE_ONCE */
+
+ /* Warning!!! Since uClibc doesn't do lib locking, the following is
+ * potentially unsafe in a multi-threaded program since it is remotely
+ * possible that another thread could call setenv() for TZ and overwrite
+ * the string being parsed. So, don't do that... */
+
+ if ((!e /* TZ env var not set... */
+#ifdef __TIME_TZ_FILE
+ && !(e = read_TZ_file(buf)) /* and no file or invalid file */
+#endif /* __TIME_TZ_FILE */
+ ) || !*e) { /* or set to empty string. */
ILLEGAL: /* TODO: Clean up the following... */
+#ifdef __TIME_TZ_OPT_SPEED
+ *oldval = 0; /* Set oldval tonnn empty string. */
+#endif /* __TIME_TZ_OPT_SPEED */
s = _time_tzinfo[0].tzname;
*s = 'U';
*++s = 'T';
@@ -1500,10 +1618,19 @@ void tzset(void)
goto DONE;
}
-
if (*e == ':') { /* Ignore leading ':'. */
++e;
}
+
+#ifdef __TIME_TZ_OPT_SPEED
+ if (strcmp(e, oldval) == 0) { /* Same string as last time... */
+ goto FAST_DONE; /* So nothing to do. */
+ }
+ /* Make a copy of the TZ env string. It won't be nul-terminated if
+ * it is too long, but it that case it will be illegal and will be reset
+ * to the empty string anyway. */
+ strncpy(oldval, e, TZ_BUFLEN);
+#endif /* __TIME_TZ_OPT_SPEED */
count = 0;
new_rules[1].tzname[0] = 0;
@@ -1518,8 +1645,9 @@ void tzset(void)
s = new_rules[count].tzname;
n = 0;
while (*e
+ && isascii(*e) /* SUSv3 requires char in portable char set. */
&& (isalpha(*e)
- || (c && (isdigit(*e) || (*e == '+') || (*e == '-'))))
+ || (c && (isalnum(*e) || (*e == '+') || (*e == '-'))))
) {
*s++ = *e++;
if (++n > TZNAME_MAX) {
@@ -1621,6 +1749,7 @@ void tzset(void)
daylight = !!new_rules[1].tzname[0];
timezone = new_rules[0].gmt_offset;
+ FAST_DONE:
TZUNLOCK;
}