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-rw-r--r--time/tzset.c134
1 files changed, 87 insertions, 47 deletions
diff --git a/time/tzset.c b/time/tzset.c
index 9eceb73cf5..d1c2c091a5 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -31,8 +31,9 @@ extern const unsigned short int __mon_yday[2][13];
extern int __use_tzfile;
extern void __tzfile_read __P ((const char *file));
-extern void __tzfile_default __P ((char *std, char *dst,
+extern void __tzfile_default __P ((const char *std, const char *dst,
long int stdoff, long int dstoff));
+extern const char * __tzstring __P ((const char *string));
extern int __tz_compute __P ((time_t timer, const struct tm *tm));
char *__tzname[2] = { (char *) "GMT", (char *) "GMT" };
@@ -53,7 +54,7 @@ weak_alias (__timezone, timezone)
timezone given in the POSIX standard TZ envariable. */
typedef struct
{
- char *name;
+ const char *name;
/* When to change. */
enum { J0, J1, M } type; /* Interpretation of: */
@@ -74,6 +75,68 @@ static tz_rule tz_rules[2];
static int compute_change __P ((tz_rule *rule, int year));
+/* Header for a list of buffers containing time zone strings. */
+struct tzstring_head
+{
+ struct tzstring_head *next;
+ /* The buffer itself immediately follows the header.
+ The buffer contains zero or more (possibly overlapping) strings.
+ The last string is followed by 2 '\0's instead of the usual 1. */
+};
+
+/* First in a list of buffers containing time zone strings.
+ All the buffers but the last are read-only. */
+static struct
+{
+ struct tzstring_head head;
+ char data[48];
+} tzstring_list;
+
+/* Size of the last buffer in the list, not counting its header. */
+static size_t tzstring_last_buffer_size = sizeof tzstring_list.data;
+
+/* Allocate a time zone string with given contents.
+ The string will never be moved or deallocated.
+ However, its contents may be shared with other such strings. */
+const char *
+__tzstring (string)
+ const char *string;
+{
+ struct tzstring_head *h = &tzstring_list.head;
+ size_t needed;
+ char *p;
+
+ /* Look through time zone string list for a duplicate of this one. */
+ for (h = &tzstring_list.head; ; h = h->next)
+ {
+ for (p = (char *) (h + 1); p[0] | p[1]; p++)
+ if (strcmp (p, string) == 0)
+ return p;
+ if (! h->next)
+ break;
+ }
+
+ /* No duplicate was found. Copy to the end of this buffer if there's room;
+ otherwise, append a large-enough new buffer to the list and use it. */
+ p++;
+ needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */
+
+ if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed)
+ {
+ size_t buffer_size = tzstring_last_buffer_size;
+ while ((buffer_size *= 2) < needed)
+ continue;
+ if (! (h = h->next = malloc (sizeof *h + buffer_size)))
+ return NULL;
+ h->next = NULL;
+ tzstring_last_buffer_size = buffer_size;
+ p = (char *) (h + 1);
+ }
+
+ strncpy (p, string, needed);
+ return p;
+}
+
static char *old_tz = NULL;
/* Interpret the TZ envariable. */
@@ -85,6 +148,7 @@ __tzset_internal (always)
static int is_initialized = 0;
register const char *tz;
register size_t l;
+ char *tzbuf;
unsigned short int hh, mm, ss;
unsigned short int whichrule;
@@ -112,12 +176,6 @@ __tzset_internal (always)
/* No change, simply return. */
return;
- /* Free old storage. */
- if (tz_rules[0].name != NULL && *tz_rules[0].name != '\0')
- free ((void *) tz_rules[0].name);
- if (tz_rules[1].name != NULL && *tz_rules[1].name != '\0' &&
- tz_rules[1].name != tz_rules[0].name)
- free ((void *) tz_rules[1].name);
tz_rules[0].name = NULL;
tz_rules[1].name = NULL;
@@ -135,16 +193,7 @@ __tzset_internal (always)
if (tz == NULL || *tz == '\0')
{
- static const char UTC[] = "UTC";
- size_t len = sizeof UTC;
- tz_rules[0].name = (char *) malloc (len);
- if (tz_rules[0].name == NULL)
- return;
- tz_rules[1].name = (char *) malloc (len);
- if (tz_rules[1].name == NULL)
- return;
- memcpy ((void *) tz_rules[0].name, UTC, len);
- memcpy ((void *) tz_rules[1].name, UTC, len);
+ tz_rules[0].name = tz_rules[1].name = "UTC";
tz_rules[0].type = tz_rules[1].type = J0;
tz_rules[0].m = tz_rules[0].n = tz_rules[0].d = 0;
tz_rules[1].m = tz_rules[1].n = tz_rules[1].d = 0;
@@ -157,11 +206,11 @@ __tzset_internal (always)
/* Clear out old state and reset to unnamed UTC. */
memset (tz_rules, 0, sizeof tz_rules);
- tz_rules[0].name = tz_rules[1].name = (char *) "";
+ tz_rules[0].name = tz_rules[1].name = "";
/* Get the standard timezone name. */
- tz_rules[0].name = (char *) malloc (strlen (tz) + 1);
- if (tz_rules[0].name == NULL)
+ tzbuf = malloc (strlen (tz) + 1);
+ if (! tzbuf)
{
/* Clear the old tz name so we will try again. */
free (old_tz);
@@ -169,25 +218,23 @@ __tzset_internal (always)
return;
}
- if (sscanf (tz, "%[^0-9,+-]", tz_rules[0].name) != 1 ||
- (l = strlen(tz_rules[0].name)) < 3)
+ if (sscanf (tz, "%[^0-9,+-]", tzbuf) != 1 ||
+ (l = strlen (tzbuf)) < 3)
{
- free (tz_rules[0].name);
- tz_rules[0].name = (char *) "";
+ free (tzbuf);
return;
}
- {
- char *n = realloc ((void *) tz_rules[0].name, l + 1);
- if (n != NULL)
- tz_rules[0].name = n;
- }
+ tz_rules[0].name = __tzstring (tzbuf);
tz += l;
/* Figure out the standard offset from UTC. */
if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))
- return;
+ {
+ free (tzbuf);
+ return;
+ }
if (*tz == '-' || *tz == '+')
tz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
@@ -196,6 +243,7 @@ __tzset_internal (always)
switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
{
default:
+ free (tzbuf);
return;
case 1:
mm = 0;
@@ -218,23 +266,14 @@ __tzset_internal (always)
/* Get the DST timezone name (if any). */
if (*tz != '\0')
{
- char *n = malloc (strlen (tz) + 1);
- if (n != NULL)
- {
- tz_rules[1].name = n;
- if (sscanf (tz, "%[^0-9,+-]", tz_rules[1].name) != 1 ||
- (l = strlen (tz_rules[1].name)) < 3)
- {
- free (n);
- tz_rules[1].name = (char *) "";
- goto done_names; /* Punt on name, set up the offsets. */
- }
- n = realloc ((void *) tz_rules[1].name, l + 1);
- if (n != NULL)
- tz_rules[1].name = n;
+ char *n = tzbuf + strlen (tzbuf) + 1;
+ if (sscanf (tz, "%[^0-9,+-]", n) != 1 ||
+ (l = strlen (n)) < 3)
+ goto done_names; /* Punt on name, set up the offsets. */
- tz += l;
- }
+ tz_rules[1].name = __tzstring (n);
+
+ tz += l;
/* Figure out the DST offset from GMT. */
if (*tz == '-' || *tz == '+')
@@ -271,6 +310,7 @@ __tzset_internal (always)
tz_rules[1].name = tz_rules[0].name;
done_names:
+ free (tzbuf);
if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0'))
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-27 15:01:45 +0000