19520565317

Committed 19 Nov 2025 11:19PM UTC coverage: 72.548% (+0.1%) from 72.449%

Build # 19520565317

Build Type

push

github

Committed by

web-flow

Commit Message

core: Verify inherited FDs are writable for stdout/stderr (#39674)

When inheriting file descriptors for stdout/stderr (either from stdin or
when making stderr inherit from stdout), we previously just assumed they
would be writable and dup'd them. This could lead to broken setups if
the inherited FD was actually opened read-only.

Before dup'ing any inherited FDs to stdout/stderr, verify they are
actually writable using the new fd_is_writable() helper. If not, fall
back to /dev/null (or reopen the terminal in the TTY case) with a
warning, rather than silently creating a broken setup where output
operations would fail.

Run Details

31 of 44 new or added lines in 3 files covered. (70.45%)

813 existing lines in 43 files now uncovered.

308541 of 425291 relevant lines covered (72.55%)

1188151.68 hits per line

Source File
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96.41

/src/shared/calendarspec.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>

#include "alloc-util.h"
#include "calendarspec.h"
#include "errno-util.h"
#include "log.h"
#include "memstream-util.h"
#include "parse-util.h"
#include "process-util.h"
#include "sort-util.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"

#define BITS_WEEKDAYS 127
#define MIN_YEAR 1970
#define MAX_YEAR 2199

/* An arbitrary limit on the length of the chains of components. We don't want to
 * build a very long linked list, which would be slow to iterate over and might cause
 * our stack to overflow. It's unlikely that legitimate uses require more than a few
 * linked components anyway. */
#define CALENDARSPEC_COMPONENTS_MAX 240

/* Let's make sure that the microsecond component is safe to be stored in an 'int' */
assert_cc(INT_MAX >= USEC_PER_SEC);

static CalendarComponent* chain_free(CalendarComponent *c) {
        while (c) {
                CalendarComponent *n = c->next;
                free_and_replace(c, n);
        }
        return NULL;
}

DEFINE_TRIVIAL_CLEANUP_FUNC(CalendarComponent*, chain_free);

CalendarSpec* calendar_spec_free(CalendarSpec *c) {

        if (!c)
                return NULL;

        chain_free(c->year);
        chain_free(c->month);
        chain_free(c->day);
        chain_free(c->hour);
        chain_free(c->minute);
        chain_free(c->microsecond);
        free(c->timezone);

        return mfree(c);
}

static int component_compare(CalendarComponent * const *a, CalendarComponent * const *b) {
        int r;

        r = CMP((*a)->start, (*b)->start);
        if (r != 0)
                return r;

        r = CMP((*a)->stop, (*b)->stop);
        if (r != 0)
                return r;

        return CMP((*a)->repeat, (*b)->repeat);
}

static void normalize_chain(CalendarComponent **c) {
        assert(c);

        size_t n = 0;
        for (CalendarComponent *i = *c; i; i = i->next) {
                n++;

                /* While we're counting the chain, also normalize 'stop'
                 * so the length of the range is a multiple of 'repeat'. */
                if (i->stop > i->start && i->repeat > 0)
                        i->stop -= (i->stop - i->start) % i->repeat;

                /* If a repeat value is specified, but it cannot even be triggered once, let's suppress it.
                 *
                 * Similarly, if the stop value is the same as the start value, then let's just make this a
                 * non-repeating chain element. */
                if ((i->stop > i->start && i->repeat > 0 && i->start + i->repeat > i->stop) ||
                    i->start == i->stop) {
                        i->repeat = 0;
                        i->stop = -1;
                }
        }

        if (n <= 1)
                return;

        CalendarComponent **b, **j;
        b = j = newa(CalendarComponent*, n);
        for (CalendarComponent *i = *c; i; i = i->next)
                *(j++) = i;

        typesafe_qsort(b, n, component_compare);

        b[n-1]->next = NULL;
        CalendarComponent *next = b[n-1];

        /* Drop non-unique entries */
        for (size_t k = n-1; k > 0; k--) {
                if (component_compare(&b[k-1], &next) == 0) {
                        free(b[k-1]);
                        continue;
                }

                b[k-1]->next = next;
                next = b[k-1];
        }

        *c = next;
}

static void fix_year(CalendarComponent *c) {
        /* Turns 12 → 2012, 89 → 1989 */

        while (c) {
                if (c->start >= 0 && c->start < 70)
                        c->start += 2000;

                if (c->stop >= 0 && c->stop < 70)
                        c->stop += 2000;

                if (c->start >= 70 && c->start < 100)
                        c->start += 1900;

                if (c->stop >= 70 && c->stop < 100)
                        c->stop += 1900;

                c = c->next;
        }
}

static void calendar_spec_normalize(CalendarSpec *c) {
        assert(c);

        if (streq_ptr(c->timezone, "UTC")) {
                c->utc = true;
                c->timezone = mfree(c->timezone);
        }

        if (c->weekdays_bits <= 0 || c->weekdays_bits >= BITS_WEEKDAYS)
                c->weekdays_bits = -1;

        if (c->end_of_month && !c->day)
                c->end_of_month = false;

        fix_year(c->year);

        normalize_chain(&c->year);
        normalize_chain(&c->month);
        normalize_chain(&c->day);
        normalize_chain(&c->hour);
        normalize_chain(&c->minute);
        normalize_chain(&c->microsecond);
}

static bool chain_valid(CalendarComponent *c, int from, int to, bool end_of_month) {
        assert(to >= from);

        if (!c)
                return true;

        /* Forbid dates more than 28 days from the end of the month */
        if (end_of_month)
                to -= 3;

        if (c->start < from || c->start > to)
                return false;

        /* Avoid overly large values that could cause overflow */
        if (c->repeat > to - from)
                return false;

        /*
         * c->repeat must be short enough so at least one repetition may
         * occur before the end of the interval.  For dates scheduled
         * relative to the end of the month, c->start and c->stop
         * correspond to the Nth last day of the month.
         */
        if (c->stop >= 0) {
                if (c->stop < from || c ->stop > to)
                        return false;

                if (c->start + c->repeat > c->stop)
                        return false;
        } else {
                if (end_of_month && c->start - c->repeat < from)
                        return false;

                if (!end_of_month && c->start + c->repeat > to)
                        return false;
        }

        if (c->next)
                return chain_valid(c->next, from, to, end_of_month);

        return true;
}

_pure_ bool calendar_spec_valid(CalendarSpec *c) {
        assert(c);

        if (c->weekdays_bits > BITS_WEEKDAYS)
                return false;

        if (!chain_valid(c->year, MIN_YEAR, MAX_YEAR, false))
                return false;

        if (!chain_valid(c->month, 1, 12, false))
                return false;

        if (!chain_valid(c->day, 1, 31, c->end_of_month))
                return false;

        if (!chain_valid(c->hour, 0, 23, false))
                return false;

        if (!chain_valid(c->minute, 0, 59, false))
                return false;

        if (!chain_valid(c->microsecond, 0, 60*USEC_PER_SEC-1, false))
                return false;

        return true;
}

static void format_weekdays(FILE *f, const CalendarSpec *c) {
        static const char *const days[] = {
                "Mon",
                "Tue",
                "Wed",
                "Thu",
                "Fri",
                "Sat",
                "Sun",
        };

        int l, x;
        bool need_comma = false;

        assert(f);
        assert(c);
        assert(c->weekdays_bits > 0 && c->weekdays_bits <= BITS_WEEKDAYS);

        for (x = 0, l = -1; x < (int) ELEMENTSOF(days); x++) {

                if (c->weekdays_bits & (1 << x)) {

                        if (l < 0) {
                                if (need_comma)
                                        fputc(',', f);
                                else
                                        need_comma = true;

                                fputs(days[x], f);
                                l = x;
                        }

                } else if (l >= 0) {

                        if (x > l + 1) {
                                fputs(x > l + 2 ? ".." : ",", f);
                                fputs(days[x-1], f);
                        }

                        l = -1;
                }
        }

        if (l >= 0 && x > l + 1) {
                fputs(x > l + 2 ? ".." : ",", f);
                fputs(days[x-1], f);
        }
}

static bool chain_is_star(const CalendarComponent *c, bool usec) {
        /* Return true if the whole chain can be replaced by '*'.
         * This happens when the chain is empty or one of the components covers all. */
        if (!c)
                return true;
        if (usec)
                for (; c; c = c->next)
                        if (c->start == 0 && c->stop < 0 && c->repeat == USEC_PER_SEC)
                                return true;
        return false;
}

static void _format_chain(FILE *f, int space, const CalendarComponent *c, bool start, bool usec) {
        int d = usec ? (int) USEC_PER_SEC : 1;

        assert(f);

        if (start && chain_is_star(c, usec)) {
                fputc('*', f);
                return;
        }

        assert(c->start >= 0);

        fprintf(f, "%0*i", space, c->start / d);
        if (c->start % d > 0)
                fprintf(f, ".%06i", c->start % d);

        if (c->stop > 0)
                fprintf(f, "..%0*i", space, c->stop / d);
        if (c->stop % d > 0)
                fprintf(f, ".%06i", c->stop % d);

        if (c->repeat > 0 && !(c->stop > 0 && c->repeat == d))
                fprintf(f, "/%i", c->repeat / d);
        if (c->repeat % d > 0)
                fprintf(f, ".%06i", c->repeat % d);

        if (c->next) {
                fputc(',', f);
                _format_chain(f, space, c->next, false, usec);
        }
}

static void format_chain(FILE *f, int space, const CalendarComponent *c, bool usec) {
        _format_chain(f, space, c, /* start = */ true, usec);
}

int calendar_spec_to_string(const CalendarSpec *c, char **ret) {
        _cleanup_(memstream_done) MemStream m = {};
        FILE *f;

        assert(c);
        assert(ret);

        f = memstream_init(&m);
        if (!f)
                return -ENOMEM;

        if (c->weekdays_bits > 0 && c->weekdays_bits <= BITS_WEEKDAYS) {
                format_weekdays(f, c);
                fputc(' ', f);
        }

        format_chain(f, 4, c->year, false);
        fputc('-', f);
        format_chain(f, 2, c->month, false);
        fputc(c->end_of_month ? '~' : '-', f);
        format_chain(f, 2, c->day, false);
        fputc(' ', f);
        format_chain(f, 2, c->hour, false);
        fputc(':', f);
        format_chain(f, 2, c->minute, false);
        fputc(':', f);
        format_chain(f, 2, c->microsecond, true);

        if (c->utc)
                fputs(" UTC", f);
        else if (c->timezone) {
                fputc(' ', f);
                fputs(c->timezone, f);
        } else if (IN_SET(c->dst, 0, 1)) {

                /* If daylight saving is explicitly on or off, let's show the used timezone. */

                tzset();

                const char *z = get_tzname(c->dst);
                if (z) {
                        fputc(' ', f);
                        fputs(z, f);
                }
        }

        return memstream_finalize(&m, ret, NULL);
}

static int parse_weekdays(const char **p, CalendarSpec *c) {
        static const struct {
                const char *name;
                const int nr;
        } day_nr[] = {
                { "Monday",    0 },
                { "Mon",       0 },
                { "Tuesday",   1 },
                { "Tue",       1 },
                { "Wednesday", 2 },
                { "Wed",       2 },
                { "Thursday",  3 },
                { "Thu",       3 },
                { "Friday",    4 },
                { "Fri",       4 },
                { "Saturday",  5 },
                { "Sat",       5 },
                { "Sunday",    6 },
                { "Sun",       6 },
        };

        int l = -1;
        bool first = true;

        assert(p);
        assert(*p);
        assert(c);

        for (;;) {
                size_t i;

                for (i = 0; i < ELEMENTSOF(day_nr); i++) {
                        size_t skip;

                        if (!startswith_no_case(*p, day_nr[i].name))
                                continue;

                        skip = strlen(day_nr[i].name);

                        if (!IN_SET((*p)[skip], 0, '-', '.', ',', ' '))
                                return -EINVAL;

                        c->weekdays_bits |= 1 << day_nr[i].nr;

                        if (l >= 0) {
                                if (l > day_nr[i].nr)
                                        return -EINVAL;

                                for (int j = l + 1; j < day_nr[i].nr; j++)
                                        c->weekdays_bits |= 1 << j;
                        }

                        *p += skip;
                        break;
                }

                /* Couldn't find this prefix, so let's assume the
                   weekday was not specified and let's continue with
                   the date */
                if (i >= ELEMENTSOF(day_nr))
                        return first ? 0 : -EINVAL;

                /* We reached the end of the string */
                if (**p == 0)
                        return 0;

                /* We reached the end of the weekday spec part */
                if (**p == ' ') {
                        *p += strspn(*p, " ");
                        return 0;
                }

                if (**p == '.') {
                        if (l >= 0)
                                return -EINVAL;

                        if ((*p)[1] != '.')
                                return -EINVAL;

                        l = day_nr[i].nr;
                        *p += 2;

                /* Support ranges with "-" for backwards compatibility */
                } else if (**p == '-') {
                        if (l >= 0)
                                return -EINVAL;

                        l = day_nr[i].nr;
                        *p += 1;

                } else if (**p == ',') {
                        l = -1;
                        *p += 1;
                }

                /* Allow a trailing comma but not an open range */
                if (IN_SET(**p, 0, ' ')) {
                        *p += strspn(*p, " ");
                        return l < 0 ? 0 : -EINVAL;
                }

                first = false;
        }
}

static int parse_one_number(const char *p, const char **e, unsigned long *ret) {
        char *ee = NULL;
        unsigned long value;

        errno = 0;
        value = strtoul(p, &ee, 10);
        if (errno > 0)
                return -errno;
        if (ee == p)
                return -EINVAL;

        *ret = value;
        *e = ee;
        return 0;
}

static int parse_component_decimal(const char **p, bool usec, int *res) {
        unsigned long value;
        const char *e = NULL;
        int r;

        if (!ascii_isdigit(**p))
                return -EINVAL;

        r = parse_one_number(*p, &e, &value);
        if (r < 0)
                return r;

        if (usec) {
                if (value * USEC_PER_SEC / USEC_PER_SEC != value)
                        return -ERANGE;

                value *= USEC_PER_SEC;

                /* One "." is a decimal point, but ".." is a range separator */
                if (e[0] == '.' && e[1] != '.') {
                        unsigned add;

                        e++;
                        r = parse_fractional_part_u(&e, 6, &add);
                        if (r < 0)
                                return r;

                        if (add + value < value)
                                return -ERANGE;
                        value += add;
                }
        }

        if (value > INT_MAX)
                return -ERANGE;

        *p = e;
        *res = value;

        return 0;
}

static int const_chain(int value, CalendarComponent **c) {
        CalendarComponent *cc = NULL;

        assert(c);

        cc = new(CalendarComponent, 1);
        if (!cc)
                return -ENOMEM;

        *cc = (CalendarComponent) {
                .start = value,
                .stop = -1,
                .repeat = 0,
                .next = *c,
        };

        *c = cc;

        return 0;
}

static int calendarspec_from_time_t(CalendarSpec *c, time_t time) {
        _cleanup_(chain_freep) CalendarComponent
                *year = NULL, *month = NULL, *day = NULL,
                *hour = NULL, *minute = NULL, *us = NULL;
        struct tm tm;
        int r;

        if ((usec_t) time > USEC_INFINITY / USEC_PER_SEC)
                return -ERANGE;

        r = localtime_or_gmtime_usec((usec_t) time * USEC_PER_SEC, /* utc= */ true, &tm);
        if (r < 0)
                return r;

        if (tm.tm_year > INT_MAX - 1900)
                return -ERANGE;

        r = const_chain(tm.tm_year + 1900, &year);
        if (r < 0)
                return r;

        r = const_chain(tm.tm_mon + 1, &month);
        if (r < 0)
                return r;

        r = const_chain(tm.tm_mday, &day);
        if (r < 0)
                return r;

        r = const_chain(tm.tm_hour, &hour);
        if (r < 0)
                return r;

        r = const_chain(tm.tm_min, &minute);
        if (r < 0)
                return r;

        r = const_chain(tm.tm_sec * USEC_PER_SEC, &us);
        if (r < 0)
                return r;

        c->utc = true;
        c->year = TAKE_PTR(year);
        c->month = TAKE_PTR(month);
        c->day = TAKE_PTR(day);
        c->hour = TAKE_PTR(hour);
        c->minute = TAKE_PTR(minute);
        c->microsecond = TAKE_PTR(us);
        return 0;
}

static int prepend_component(const char **p, bool usec, unsigned nesting, CalendarComponent **c) {
        int r, start, stop = -1, repeat = 0;
        CalendarComponent *cc;
        const char *e = *p;

        assert(p);
        assert(c);

        if (nesting > CALENDARSPEC_COMPONENTS_MAX)
                return -ENOBUFS;

        r = parse_component_decimal(&e, usec, &start);
        if (r < 0)
                return r;

        if (e[0] == '.' && e[1] == '.') {
                e += 2;
                r = parse_component_decimal(&e, usec, &stop);
                if (r < 0)
                        return r;

                repeat = usec ? USEC_PER_SEC : 1;
        }

        if (*e == '/') {
                e++;
                r = parse_component_decimal(&e, usec, &repeat);
                if (r < 0)
                        return r;

                if (repeat == 0)
                        return -ERANGE;
        } else {
                /* If no repeat value is specified for the μs component, then let's explicitly refuse ranges
                 * below 1s because our default repeat granularity is beyond that. */

                /* Overflow check */
                if (start > INT_MAX - repeat)
                        return -ERANGE;

                if (usec && stop >= 0 && start + repeat > stop)
                        return -EINVAL;
        }

        if (!IN_SET(*e, 0, ' ', ',', '-', '~', ':'))
                return -EINVAL;

        cc = new(CalendarComponent, 1);
        if (!cc)
                return -ENOMEM;

        *cc = (CalendarComponent) {
                .start = start,
                .stop = stop,
                .repeat = repeat,
                .next = *c,
        };

        *p = e;
        *c = cc;

        if (*e ==',') {
                *p += 1;
                return prepend_component(p, usec, nesting + 1, c);
        }

        return 0;
}

static int parse_chain(const char **p, bool usec, CalendarComponent **c) {
        _cleanup_(chain_freep) CalendarComponent *cc = NULL;
        const char *t;
        int r;

        assert(p);
        assert(c);

        t = *p;

        if (t[0] == '*') {
                if (usec) {
                        r = const_chain(0, c);
                        if (r < 0)
                                return r;
                        (*c)->repeat = USEC_PER_SEC;
                } else
                        *c = NULL;

                *p = t + 1;
                return 0;
        }

        r = prepend_component(&t, usec, 0, &cc);
        if (r < 0)
                return r;

        *p = t;
        *c = TAKE_PTR(cc);
        return 0;
}

static int parse_date(const char **p, CalendarSpec *c) {
        _cleanup_(chain_freep) CalendarComponent *first = NULL, *second = NULL, *third = NULL;
        const char *t;
        int r;

        assert(p);
        assert(*p);
        assert(c);

        t = *p;

        if (*t == 0)
                return 0;

        /* @TIMESTAMP — UNIX time in seconds since the epoch */
        if (*t == '@') {
                unsigned long value;
                time_t time;

                r = parse_one_number(t + 1, &t, &value);
                if (r < 0)
                        return r;

                time = value;
                if ((unsigned long) time != value)
                        return -ERANGE;

                r = calendarspec_from_time_t(c, time);
                if (r < 0)
                        return r;

                *p = t;
                return 1; /* finito, don't parse H:M:S after that */
        }

        r = parse_chain(&t, false, &first);
        if (r < 0)
                return r;

        /* Already the end? A ':' as separator? In that case this was a time, not a date */
        if (IN_SET(*t, 0, ':'))
                return 0;

        if (*t == '~')
                c->end_of_month = true;
        else if (*t != '-')
                return -EINVAL;

        t++;
        r = parse_chain(&t, false, &second);
        if (r < 0)
                return r;

        /* Got two parts, hence it's month and day */
        if (IN_SET(*t, 0, ' ')) {
                *p = t + strspn(t, " ");
                c->month = TAKE_PTR(first);
                c->day = TAKE_PTR(second);
                return 0;
        } else if (c->end_of_month)
                return -EINVAL;

        if (*t == '~')
                c->end_of_month = true;
        else if (*t != '-')
                return -EINVAL;

        t++;
        r = parse_chain(&t, false, &third);
        if (r < 0)
                return r;

        if (!IN_SET(*t, 0, ' '))
                return -EINVAL;

        /* Got three parts, hence it is year, month and day */
        *p = t + strspn(t, " ");
        c->year = TAKE_PTR(first);
        c->month = TAKE_PTR(second);
        c->day = TAKE_PTR(third);
        return 0;
}

static int parse_calendar_time(const char **p, CalendarSpec *c) {
        _cleanup_(chain_freep) CalendarComponent *h = NULL, *m = NULL, *s = NULL;
        const char *t;
        int r;

        assert(p);
        assert(*p);
        assert(c);

        t = *p;

        /* If no time is specified at all, then this means 00:00:00 */
        if (*t == 0)
                goto null_hour;

        r = parse_chain(&t, false, &h);
        if (r < 0)
                return r;

        if (*t != ':')
                return -EINVAL;

        t++;
        r = parse_chain(&t, false, &m);
        if (r < 0)
                return r;

        /* Already at the end? Then it's hours and minutes, and seconds are 0 */
        if (*t == 0)
                goto null_second;

        if (*t != ':')
                return -EINVAL;

        t++;
        r = parse_chain(&t, true, &s);
        if (r < 0)
                return r;

        /* At the end? Then it's hours, minutes and seconds */
        if (*t == 0)
                goto finish;

        return -EINVAL;

null_hour:
        r = const_chain(0, &h);
        if (r < 0)
                return r;

        r = const_chain(0, &m);
        if (r < 0)
                return r;

null_second:
        r = const_chain(0, &s);
        if (r < 0)
                return r;

finish:
        *p = t;
        c->hour = TAKE_PTR(h);
        c->minute = TAKE_PTR(m);
        c->microsecond = TAKE_PTR(s);

        return 0;
}

int calendar_spec_from_string(const char *p, CalendarSpec **ret) {
        const char *utc;
        _cleanup_(calendar_spec_freep) CalendarSpec *c = NULL;
        _cleanup_free_ char *p_tmp = NULL;
        int r;

        assert(p);

        c = new(CalendarSpec, 1);
        if (!c)
                return -ENOMEM;

        *c = (CalendarSpec) {
                .dst = -1,
                .timezone = NULL,
        };

        utc = endswith_no_case(p, " UTC");
        if (utc) {
                c->utc = true;
                p = p_tmp = strndup(p, utc - p);
                if (!p)
                        return -ENOMEM;
        } else {
                const char *e = NULL;
                int j;

                tzset();

                /* Check if the local timezone was specified? */
                for (j = 0; j <= 1; j++) {
                        const char *z = get_tzname(j);
                        if (!z)
                                continue;

                        e = endswith_no_case(p, z);
                        if (!e)
                                continue;
                        if (e == p)
                                continue;
                        if (e[-1] != ' ')
                                continue;

                        break;
                }

                /* Found one of the two timezones specified? */
                if (IN_SET(j, 0, 1)) {
                        p = p_tmp = strndup(p, e - p - 1);
                        if (!p)
                                return -ENOMEM;

                        c->dst = j;
                } else {
                        const char *last_space;

                        last_space = strrchr(p, ' ');
                        if (last_space != NULL && timezone_is_valid(last_space + 1, LOG_DEBUG)) {
                                c->timezone = strdup(last_space + 1);
                                if (!c->timezone)
                                        return -ENOMEM;

                                p = p_tmp = strndup(p, last_space - p);
                                if (!p)
                                        return -ENOMEM;
                        }
                }
        }

        if (isempty(p))
                return -EINVAL;

        if (strcaseeq(p, "minutely")) {
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (strcaseeq(p, "hourly")) {
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (strcaseeq(p, "daily")) {
                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (strcaseeq(p, "monthly")) {
                r = const_chain(1, &c->day);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (STRCASE_IN_SET(p,
                                  "annually",
                                  "yearly",
                                  "anually") /* backwards compatibility */ ) {

                r = const_chain(1, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(1, &c->day);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (strcaseeq(p, "weekly")) {

                c->weekdays_bits = 1;

                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (strcaseeq(p, "quarterly")) {

                r = const_chain(1, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(4, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(7, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(10, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(1, &c->day);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else if (STRCASE_IN_SET(p,
                                  "biannually",
                                  "bi-annually",
                                  "semiannually",
                                  "semi-annually")) {

                r = const_chain(1, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(7, &c->month);
                if (r < 0)
                        return r;
                r = const_chain(1, &c->day);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->hour);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->minute);
                if (r < 0)
                        return r;
                r = const_chain(0, &c->microsecond);
                if (r < 0)
                        return r;

        } else {
                r = parse_weekdays(&p, c);
                if (r < 0)
                        return r;

                r = parse_date(&p, c);
                if (r < 0)
                        return r;

                if (r == 0) {
                        r = parse_calendar_time(&p, c);
                        if (r < 0)
                                return r;
                }

                if (*p != 0)
                        return -EINVAL;
        }

        calendar_spec_normalize(c);

        if (!calendar_spec_valid(c))
                return -EINVAL;

        if (ret)
                *ret = TAKE_PTR(c);
        return 0;
}

static int find_end_of_month(const struct tm *tm, bool utc, int day) {
        struct tm t = *ASSERT_PTR(tm);

        t.tm_mon++;
        t.tm_mday = 1 - day;

        if (mktime_or_timegm_usec(&t, utc, /* ret= */ NULL) < 0 ||
            t.tm_mon != tm->tm_mon)
                return -1;

        return t.tm_mday;
}

static int find_matching_component(
                const CalendarSpec *spec,
                const CalendarComponent *c,
                const struct tm *tm,           /* tm is only used for end-of-month calculations */
                int *val) {

        int d = -1, r;
        bool d_set = false;

        assert(val);

        /* Finds the *earliest* matching time specified by one of the CalendarCompoment items in chain c.
         * If no matches can be found, returns -ENOENT.
         * Otherwise, updates *val to the matching time. 1 is returned if *val was changed, 0 otherwise.
         */

        if (!c)
                return 0;

        bool end_of_month = spec->end_of_month && c == spec->day;

        while (c) {
                int start, stop;

                if (end_of_month) {
                        start = find_end_of_month(tm, spec->utc, c->start);
                        stop = find_end_of_month(tm, spec->utc, c->stop);

                        if (stop > 0)
                                SWAP_TWO(start, stop);
                } else {
                        start = c->start;
                        stop = c->stop;
                }

                if (start >= *val) {

                        if (!d_set || start < d) {
                                d = start;
                                d_set = true;
                        }

                } else if (c->repeat > 0) {
                        int k;

                        k = start + ROUND_UP(*val - start, c->repeat);

                        if ((!d_set || k < d) && (stop < 0 || k <= stop)) {
                                d = k;
                                d_set = true;
                        }
                }

                c = c->next;
        }

        if (!d_set)
                return -ENOENT;

        r = *val != d;
        *val = d;
        return r;
}

static int tm_within_bounds(struct tm *tm, bool utc) {
        int r;

        assert(tm);

        /*
         * Set an upper bound on the year so impossible dates like "*-02-31"
         * don't cause find_next() to loop forever. tm_year contains years
         * since 1900, so adjust it accordingly.
         */
        if (tm->tm_year + 1900 > MAX_YEAR)
                return -ERANGE;

        struct tm t = *tm;
        r = mktime_or_timegm_usec(&t, utc, /* ret= */ NULL);
        if (r < 0)
                return r;

        /*
         * Did any normalization take place? If so, it was out of bounds before.
         * Normalization could skip next elapse, e.g. result of normalizing 3-33
         * is 4-2. This skips 4-1. So reset the sub time unit if upper unit was
         * out of bounds. Normalization has occurred implies find_matching_component() > 0,
         * other sub time units are already reset in find_next().
         */
        int cmp;
        if ((cmp = CMP(t.tm_year, tm->tm_year)) != 0)
                t.tm_mon = 0;
        else if ((cmp = CMP(t.tm_mon, tm->tm_mon)) != 0)
                t.tm_mday = 1;
        else if ((cmp = CMP(t.tm_mday, tm->tm_mday)) != 0)
                t.tm_hour = 0;
        else if ((cmp = CMP(t.tm_hour, tm->tm_hour)) != 0)
                t.tm_min = 0;
        else if ((cmp = CMP(t.tm_min, tm->tm_min)) != 0)
                t.tm_sec = 0;
        else
                cmp = CMP(t.tm_sec, tm->tm_sec);

        if (cmp < 0)
                return -EDEADLK; /* Refuse to go backward */
        if (cmp > 0)
                *tm = t;
        return cmp == 0;
}

static bool matches_weekday(int weekdays_bits, const struct tm *tm, bool utc) {
        struct tm t;
        int k;

        if (weekdays_bits < 0 || weekdays_bits >= BITS_WEEKDAYS)
                return true;

        t = *tm;
        if (mktime_or_timegm_usec(&t, utc, /* ret= */ NULL) < 0)
                return false;

        k = t.tm_wday == 0 ? 6 : t.tm_wday - 1;
        return (weekdays_bits & (1 << k));
}

static int tm_compare(const struct tm *t1, const struct tm *t2) {
        int r;

        assert(t1);
        assert(t2);

        r = CMP(t1->tm_year, t2->tm_year);
        if (r != 0)
                return r;

        r = CMP(t1->tm_mon, t2->tm_mon);
        if (r != 0)
                return r;

        r = CMP(t1->tm_mday, t2->tm_mday);
        if (r != 0)
                return r;

        r = CMP(t1->tm_hour, t2->tm_hour);
        if (r != 0)
                return r;

        r = CMP(t1->tm_min, t2->tm_min);
        if (r != 0)
                return r;

        return CMP(t1->tm_sec, t2->tm_sec);
}

/* A safety valve: if we get stuck in the calculation, return an error.
 * C.f. https://bugzilla.redhat.com/show_bug.cgi?id=1941335. */
#define MAX_CALENDAR_ITERATIONS 1000

static int find_next(const CalendarSpec *spec, struct tm *tm, usec_t *usec) {
        struct tm c;
        int tm_usec, r;
        bool invalidate_dst = false;

        /* Returns -ENOENT if the expression is not going to elapse anymore */

        assert(spec);
        assert(tm);

        c = *tm;
        tm_usec = *usec;

        for (unsigned iteration = 0; iteration < MAX_CALENDAR_ITERATIONS; iteration++) {
                /* Normalize the current date */
                (void) mktime_or_timegm_usec(&c, spec->utc, /* ret= */ NULL);
                if (!invalidate_dst)
                        c.tm_isdst = spec->dst;

                c.tm_year += 1900;
                r = find_matching_component(spec, spec->year, &c, &c.tm_year);
                c.tm_year -= 1900;

                if (r > 0) {
                        c.tm_mon = 0;
                        c.tm_mday = 1;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                }
                if (r < 0)
                        return r;
                if (tm_within_bounds(&c, spec->utc) <= 0)
                        return -ENOENT;

                c.tm_mon += 1;
                r = find_matching_component(spec, spec->month, &c, &c.tm_mon);
                c.tm_mon -= 1;

                if (r > 0) {
                        c.tm_mday = 1;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                }
                if (r < 0 || (r = tm_within_bounds(&c, spec->utc)) < 0) {
                        c.tm_year++;
                        c.tm_mon = 0;
                        c.tm_mday = 1;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                        continue;
                }
                if (r == 0)
                        continue;

                r = find_matching_component(spec, spec->day, &c, &c.tm_mday);
                if (r > 0)
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                if (r < 0 || (r = tm_within_bounds(&c, spec->utc)) < 0) {
                        c.tm_mon++;
                        c.tm_mday = 1;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                        continue;
                }
                if (r == 0)
                        continue;

                if (!matches_weekday(spec->weekdays_bits, &c, spec->utc)) {
                        c.tm_mday++;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                        continue;
                }

                r = find_matching_component(spec, spec->hour, &c, &c.tm_hour);
                if (r > 0)
                        c.tm_min = c.tm_sec = tm_usec = 0;
                if (r < 0 || (r = tm_within_bounds(&c, spec->utc)) < 0) {
                        c.tm_mday++;
                        c.tm_hour = c.tm_min = c.tm_sec = tm_usec = 0;
                        continue;
                }
                if (r == 0)
                        /* The next hour we set might be missing if there
                         * are time zone changes. Let's try again starting at
                         * normalized time. */
                        continue;

                r = find_matching_component(spec, spec->minute, &c, &c.tm_min);
                if (r > 0)
                        c.tm_sec = tm_usec = 0;
                if (r < 0 || (r = tm_within_bounds(&c, spec->utc)) < 0) {
                        c.tm_hour++;
                        c.tm_min = c.tm_sec = tm_usec = 0;
                        continue;
                }
                if (r == 0)
                        continue;

                c.tm_sec = c.tm_sec * USEC_PER_SEC + tm_usec;
                r = find_matching_component(spec, spec->microsecond, &c, &c.tm_sec);
                tm_usec = c.tm_sec % USEC_PER_SEC;
                c.tm_sec /= USEC_PER_SEC;

                if (r < 0 || (r = tm_within_bounds(&c, spec->utc)) < 0) {
                        c.tm_min++;
                        c.tm_sec = tm_usec = 0;
                        continue;
                }
                if (r == 0)
                        continue;

                r = tm_compare(tm, &c);
                if (r == 0) {
                        assert(tm_usec + 1 <= 1000000);
                        r = CMP(*usec, (usec_t) tm_usec + 1);
                }
                if (r >= 0) {
                        /* We're stuck - advance, let mktime determine DST transition and try again. */
                        invalidate_dst = true;
                        c.tm_hour++;
                        continue;
                }

                *tm = c;
                *usec = tm_usec;
                return 0;
        }

        /* It seems we entered an infinite loop. Let's gracefully return an error instead of hanging or
         * aborting. This code is also exercised when timers.target is brought up during early boot, so
         * aborting here is problematic and hard to diagnose for users. */
        _cleanup_free_ char *s = NULL;
        (void) calendar_spec_to_string(spec, &s);
        return log_warning_errno(SYNTHETIC_ERRNO(EDEADLK),
                                 "Infinite loop in calendar calculation: %s", strna(s));
}

static int calendar_spec_next_usec_impl(const CalendarSpec *spec, usec_t usec, usec_t *ret_next) {
        usec_t tm_usec;
        struct tm tm;
        int r;

        assert(spec);

        if (usec > USEC_TIMESTAMP_FORMATTABLE_MAX)
                return -EINVAL;

        usec++;
        r = localtime_or_gmtime_usec(usec, spec->utc, &tm);
        if (r < 0)
                return r;
        tm_usec = usec % USEC_PER_SEC;

        r = find_next(spec, &tm, &tm_usec);
        if (r < 0)
                return r;

        usec_t t;
        r = mktime_or_timegm_usec(&tm, spec->utc, &t);
        if (r < 0)
                return r;

        if (ret_next)
                *ret_next = t + tm_usec;

        return 0;
}

int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *ret_next) {
        int r;

        assert(spec);

        if (isempty(spec->timezone))
                return calendar_spec_next_usec_impl(spec, usec, ret_next);

        SAVE_TIMEZONE;

        r = RET_NERRNO(setenv("TZ", spec->timezone, /* overwrite = */ true));
        if (r < 0)
                return r;

        tzset();

        return calendar_spec_next_usec_impl(spec, usec, ret_next);
}

systemd / systemd / 19520565317

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