postgresql/src/backend/utils/misc/tzparser.c

486 lines
12 KiB
C

/*-------------------------------------------------------------------------
*
* tzparser.c
* Functions for parsing timezone offset files
*
* Note: this code is invoked from the check_hook for the GUC variable
* timezone_abbreviations. Therefore, it should report problems using
* GUC_check_errmsg() and related functions, and try to avoid throwing
* elog(ERROR). This is not completely bulletproof at present --- in
* particular out-of-memory will throw an error. Could probably fix with
* PG_TRY if necessary.
*
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/misc/tzparser.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <ctype.h>
#include "miscadmin.h"
#include "storage/fd.h"
#include "utils/datetime.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/tzparser.h"
#define WHITESPACE " \t\n\r"
static bool validateTzEntry(tzEntry *tzentry);
static bool splitTzLine(const char *filename, int lineno,
char *line, tzEntry *tzentry);
static int addToArray(tzEntry **base, int *arraysize, int n,
tzEntry *entry, bool override);
static int ParseTzFile(const char *filename, int depth,
tzEntry **base, int *arraysize, int n);
/*
* Apply additional validation checks to a tzEntry
*
* Returns true if OK, else false
*/
static bool
validateTzEntry(tzEntry *tzentry)
{
unsigned char *p;
/*
* Check restrictions imposed by datetktbl storage format (see datetime.c)
*/
if (strlen(tzentry->abbrev) > TOKMAXLEN)
{
GUC_check_errmsg("time zone abbreviation \"%s\" is too long (maximum %d characters) in time zone file \"%s\", line %d",
tzentry->abbrev, TOKMAXLEN,
tzentry->filename, tzentry->lineno);
return false;
}
/*
* Sanity-check the offset: shouldn't exceed 14 hours
*/
if (tzentry->offset > 14 * SECS_PER_HOUR ||
tzentry->offset < -14 * SECS_PER_HOUR)
{
GUC_check_errmsg("time zone offset %d is out of range in time zone file \"%s\", line %d",
tzentry->offset,
tzentry->filename, tzentry->lineno);
return false;
}
/*
* Convert abbrev to lowercase (must match datetime.c's conversion)
*/
for (p = (unsigned char *) tzentry->abbrev; *p; p++)
*p = pg_tolower(*p);
return true;
}
/*
* Attempt to parse the line as a timezone abbrev spec
*
* Valid formats are:
* name zone
* name offset dst
*
* Returns true if OK, else false; data is stored in *tzentry
*/
static bool
splitTzLine(const char *filename, int lineno, char *line, tzEntry *tzentry)
{
char *abbrev;
char *offset;
char *offset_endptr;
char *remain;
char *is_dst;
tzentry->lineno = lineno;
tzentry->filename = filename;
abbrev = strtok(line, WHITESPACE);
if (!abbrev)
{
GUC_check_errmsg("missing time zone abbreviation in time zone file \"%s\", line %d",
filename, lineno);
return false;
}
tzentry->abbrev = pstrdup(abbrev);
offset = strtok(NULL, WHITESPACE);
if (!offset)
{
GUC_check_errmsg("missing time zone offset in time zone file \"%s\", line %d",
filename, lineno);
return false;
}
/* We assume zone names don't begin with a digit or sign */
if (isdigit((unsigned char) *offset) || *offset == '+' || *offset == '-')
{
tzentry->zone = NULL;
tzentry->offset = strtol(offset, &offset_endptr, 10);
if (offset_endptr == offset || *offset_endptr != '\0')
{
GUC_check_errmsg("invalid number for time zone offset in time zone file \"%s\", line %d",
filename, lineno);
return false;
}
is_dst = strtok(NULL, WHITESPACE);
if (is_dst && pg_strcasecmp(is_dst, "D") == 0)
{
tzentry->is_dst = true;
remain = strtok(NULL, WHITESPACE);
}
else
{
/* there was no 'D' dst specifier */
tzentry->is_dst = false;
remain = is_dst;
}
}
else
{
/*
* Assume entry is a zone name. We do not try to validate it by
* looking up the zone, because that would force loading of a lot of
* zones that probably will never be used in the current session.
*/
tzentry->zone = pstrdup(offset);
tzentry->offset = 0 * SECS_PER_HOUR;
tzentry->is_dst = false;
remain = strtok(NULL, WHITESPACE);
}
if (!remain) /* no more non-whitespace chars */
return true;
if (remain[0] != '#') /* must be a comment */
{
GUC_check_errmsg("invalid syntax in time zone file \"%s\", line %d",
filename, lineno);
return false;
}
return true;
}
/*
* Insert entry into sorted array
*
* *base: base address of array (changeable if must enlarge array)
* *arraysize: allocated length of array (changeable if must enlarge array)
* n: current number of valid elements in array
* entry: new data to insert
* override: true if OK to override
*
* Returns the new array length (new value for n), or -1 if error
*/
static int
addToArray(tzEntry **base, int *arraysize, int n,
tzEntry *entry, bool override)
{
tzEntry *arrayptr;
int low;
int high;
/*
* Search the array for a duplicate; as a useful side effect, the array is
* maintained in sorted order. We use strcmp() to ensure we match the
* sort order datetime.c expects.
*/
arrayptr = *base;
low = 0;
high = n - 1;
while (low <= high)
{
int mid = (low + high) >> 1;
tzEntry *midptr = arrayptr + mid;
int cmp;
cmp = strcmp(entry->abbrev, midptr->abbrev);
if (cmp < 0)
high = mid - 1;
else if (cmp > 0)
low = mid + 1;
else
{
/*
* Found a duplicate entry; complain unless it's the same.
*/
if ((midptr->zone == NULL && entry->zone == NULL &&
midptr->offset == entry->offset &&
midptr->is_dst == entry->is_dst) ||
(midptr->zone != NULL && entry->zone != NULL &&
strcmp(midptr->zone, entry->zone) == 0))
{
/* return unchanged array */
return n;
}
if (override)
{
/* same abbrev but something is different, override */
midptr->zone = entry->zone;
midptr->offset = entry->offset;
midptr->is_dst = entry->is_dst;
return n;
}
/* same abbrev but something is different, complain */
GUC_check_errmsg("time zone abbreviation \"%s\" is multiply defined",
entry->abbrev);
GUC_check_errdetail("Entry in time zone file \"%s\", line %d, conflicts with entry in file \"%s\", line %d.",
midptr->filename, midptr->lineno,
entry->filename, entry->lineno);
return -1;
}
}
/*
* No match, insert at position "low".
*/
if (n >= *arraysize)
{
*arraysize *= 2;
*base = (tzEntry *) repalloc(*base, *arraysize * sizeof(tzEntry));
}
arrayptr = *base + low;
memmove(arrayptr + 1, arrayptr, (n - low) * sizeof(tzEntry));
memcpy(arrayptr, entry, sizeof(tzEntry));
return n + 1;
}
/*
* Parse a single timezone abbrev file --- can recurse to handle @INCLUDE
*
* filename: user-specified file name (does not include path)
* depth: current recursion depth
* *base: array for results (changeable if must enlarge array)
* *arraysize: allocated length of array (changeable if must enlarge array)
* n: current number of valid elements in array
*
* Returns the new array length (new value for n), or -1 if error
*/
static int
ParseTzFile(const char *filename, int depth,
tzEntry **base, int *arraysize, int n)
{
char share_path[MAXPGPATH];
char file_path[MAXPGPATH];
FILE *tzFile;
char tzbuf[1024];
char *line;
tzEntry tzentry;
int lineno = 0;
bool override = false;
const char *p;
/*
* We enforce that the filename is all alpha characters. This may be
* overly restrictive, but we don't want to allow access to anything
* outside the timezonesets directory, so for instance '/' *must* be
* rejected.
*/
for (p = filename; *p; p++)
{
if (!isalpha((unsigned char) *p))
{
/* at level 0, just use guc.c's regular "invalid value" message */
if (depth > 0)
GUC_check_errmsg("invalid time zone file name \"%s\"",
filename);
return -1;
}
}
/*
* The maximal recursion depth is a pretty arbitrary setting. It is hard
* to imagine that someone needs more than 3 levels so stick with this
* conservative setting until someone complains.
*/
if (depth > 3)
{
GUC_check_errmsg("time zone file recursion limit exceeded in file \"%s\"",
filename);
return -1;
}
get_share_path(my_exec_path, share_path);
snprintf(file_path, sizeof(file_path), "%s/timezonesets/%s",
share_path, filename);
tzFile = AllocateFile(file_path, "r");
if (!tzFile)
{
/*
* Check to see if the problem is not the filename but the directory.
* This is worth troubling over because if the installation share/
* directory is missing or unreadable, this is likely to be the first
* place we notice a problem during postmaster startup.
*/
int save_errno = errno;
DIR *tzdir;
snprintf(file_path, sizeof(file_path), "%s/timezonesets",
share_path);
tzdir = AllocateDir(file_path);
if (tzdir == NULL)
{
GUC_check_errmsg("could not open directory \"%s\": %m",
file_path);
GUC_check_errhint("This may indicate an incomplete PostgreSQL installation, or that the file \"%s\" has been moved away from its proper location.",
my_exec_path);
return -1;
}
FreeDir(tzdir);
errno = save_errno;
/*
* otherwise, if file doesn't exist and it's level 0, guc.c's
* complaint is enough
*/
if (errno != ENOENT || depth > 0)
GUC_check_errmsg("could not read time zone file \"%s\": %m",
filename);
return -1;
}
while (!feof(tzFile))
{
lineno++;
if (fgets(tzbuf, sizeof(tzbuf), tzFile) == NULL)
{
if (ferror(tzFile))
{
GUC_check_errmsg("could not read time zone file \"%s\": %m",
filename);
n = -1;
break;
}
/* else we're at EOF after all */
break;
}
if (strlen(tzbuf) == sizeof(tzbuf) - 1)
{
/* the line is too long for tzbuf */
GUC_check_errmsg("line is too long in time zone file \"%s\", line %d",
filename, lineno);
n = -1;
break;
}
/* skip over whitespace */
line = tzbuf;
while (*line && isspace((unsigned char) *line))
line++;
if (*line == '\0') /* empty line */
continue;
if (*line == '#') /* comment line */
continue;
if (pg_strncasecmp(line, "@INCLUDE", strlen("@INCLUDE")) == 0)
{
/* pstrdup so we can use filename in result data structure */
char *includeFile = pstrdup(line + strlen("@INCLUDE"));
includeFile = strtok(includeFile, WHITESPACE);
if (!includeFile || !*includeFile)
{
GUC_check_errmsg("@INCLUDE without file name in time zone file \"%s\", line %d",
filename, lineno);
n = -1;
break;
}
n = ParseTzFile(includeFile, depth + 1,
base, arraysize, n);
if (n < 0)
break;
continue;
}
if (pg_strncasecmp(line, "@OVERRIDE", strlen("@OVERRIDE")) == 0)
{
override = true;
continue;
}
if (!splitTzLine(filename, lineno, line, &tzentry))
{
n = -1;
break;
}
if (!validateTzEntry(&tzentry))
{
n = -1;
break;
}
n = addToArray(base, arraysize, n, &tzentry, override);
if (n < 0)
break;
}
FreeFile(tzFile);
return n;
}
/*
* load_tzoffsets --- read and parse the specified timezone offset file
*
* On success, return a filled-in TimeZoneAbbrevTable, which must have been
* guc_malloc'd not palloc'd. On failure, return NULL, using GUC_check_errmsg
* and friends to give details of the problem.
*/
TimeZoneAbbrevTable *
load_tzoffsets(const char *filename)
{
TimeZoneAbbrevTable *result = NULL;
MemoryContext tmpContext;
MemoryContext oldContext;
tzEntry *array;
int arraysize;
int n;
/*
* Create a temp memory context to work in. This makes it easy to clean
* up afterwards.
*/
tmpContext = AllocSetContextCreate(CurrentMemoryContext,
"TZParserMemory",
ALLOCSET_SMALL_SIZES);
oldContext = MemoryContextSwitchTo(tmpContext);
/* Initialize array at a reasonable size */
arraysize = 128;
array = (tzEntry *) palloc(arraysize * sizeof(tzEntry));
/* Parse the file(s) */
n = ParseTzFile(filename, 0, &array, &arraysize, 0);
/* If no errors so far, let datetime.c allocate memory & convert format */
if (n >= 0)
{
result = ConvertTimeZoneAbbrevs(array, n);
if (!result)
GUC_check_errmsg("out of memory");
}
/* Clean up */
MemoryContextSwitchTo(oldContext);
MemoryContextDelete(tmpContext);
return result;
}