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-rw-r--r--src/backend/utils/misc/tzparser.c484
1 files changed, 484 insertions, 0 deletions
diff --git a/src/backend/utils/misc/tzparser.c b/src/backend/utils/misc/tzparser.c
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+/*-------------------------------------------------------------------------
+ *
+ * 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) 1996-2021, 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/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 * 60 * 60 ||
+ tzentry->offset < -14 * 60 * 60)
+ {
+ 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;
+ 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
+ * 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;
+}
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