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[PROPOSED] Be more like OpenBSD wrt ".."
by Paul Eggert Oct. 25, 2025

Oct. 25, 2025

* localtime.c (tzloadbody): Do not worry about settings like TZ=".." (i.e., trailing ".." component) as the later read will fail anyway. This simplifies the code slightly, and agrees with the security-conscious OpenBSD libc. --- localtime.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/localtime.c b/localtime.c index f1a82370..0d2d2a93 100644 --- a/localtime.c +++ b/localtime.c @@ -941,13 +941,13 @@ tzloadbody(char const *name, struct state *sp, char tzloadflags, if (relname[0] != '/') { if (!OPENAT_TZDIR || !O_RESOLVE_BENEATH) { - /* Fail if a relative name contains a ".." component, - as such a name could read a file outside TZDIR + /* Fail if a relative name contains a non-terminal ".." component, + as such a name could read a non-directory outside TZDIR when AT_FDCWD and O_RESOLVE_BENEATH are not available. */ char const *component; for (component = relname; component[0]; component++) if (component[0] == '.' && component[1] == '.' - && ((component[2] == '/') | !component[2]) + && component[2] == '/' && (component == relname || component[-1] == '/')) return ENOTCAPABLE; } -- 2.48.1

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[PATCH 1/5] Clarify <sys/auxv.h> vs getauxval
by Paul Eggert Oct. 25, 2025

Oct. 25, 2025

FreeBSD has <sys/auxv.h> but not getauxval, so clarify ifdeffery to reflect this. This doesn’t fix any bugs (since FreeBSD also has issetugid) but makes things clearer. * Makefile, NEWS: Update to match new behavior and fix a few old typos. * localtime.c: Move the <sys/auv.h> code to be closer together. (HAVE_SYS_AUXV_H) [!HAVE_ISSETUGID]: New macro. * private.h (HAVE_GETAUXVAL): Remove. All uses replaced by HAVE_SYS_AUXV_H. --- Makefile | 12 ++++++------ NEWS | 9 +++++---- localtime.c | 25 +++++++++++++++++++------ private.h | 13 ------------- 4 files changed, 30 insertions(+), 29 deletions(-) diff --git a/Makefile b/Makefile index 3b259c80..0fe8a9f8 100644 --- a/Makefile +++ b/Makefile @@ -246,7 +246,6 @@ LDLIBS= # -DHAVE_DIRECT_H if mkdir needs <direct.h> (MS-Windows) # -DHAVE_FCHMOD=0 if your system lacks the fchmod function # -DHAVE__GENERIC=0 if _Generic does not work* -# -DHAVE_GETAUXVAL=1 if getauxval works, 0 otherwise (default is guessed) # -DHAVE_GETEUID=0 if gete?[ug]id do not work # -DHAVE_GETRANDOM if getrandom works (e.g., GNU/Linux), # -DHAVE_GETRANDOM=0 to avoid using getrandom @@ -258,7 +257,9 @@ LDLIBS= # ctime_r and asctime_r incompatibly with POSIX.1-2017 and earlier # (Solaris when _POSIX_PTHREAD_SEMANTICS is not defined). # -DHAVE_INTTYPES_H=0 if <inttypes.h> does not work*+ -# -DHAVE_ISSETUID=1 if issetugid works, 0 otherwise (default is guessed) +# -DHAVE_ISSETUGID=1 if issetugid works, 0 otherwise (default is guessed) +# If 0, you may also use -DHAVE_SYS_AUXV_H=1 if <sys/auxv.h> works, +# 0 otherwise (default is guessed). # -DHAVE_LINK=0 if your system lacks a link function # -DHAVE_LOCALTIME_R=0 if your system lacks a localtime_r function # -DHAVE_LOCALTIME_RZ=0 if you do not want zdump to use localtime_rz @@ -268,8 +269,8 @@ LDLIBS= # -DHAVE_POSIX_DECLS=0 if your system's include files do not declare # variables like 'tzname' required by POSIX # -DHAVE_PWD_H=0 if your system lacks pwd.h, grp.h and corresponding functions -# The following additional options may be needed: -# -Dgid_t=T, -Duid_t=T to define gid_t, uid_t to be type T +# If 0, you may also need -Dgid_t=G -Duid_t=U +# to define gid_t and uid_t to be types G and U. # -DHAVE_SETENV=0 if your system lacks the setenv function # -DHAVE_SETMODE=[01] if your system lacks or has the setmode and getmode # functions (default is guessed) @@ -285,8 +286,7 @@ LDLIBS= # -DHAVE_STRUCT_TIMESPEC=0 if your system lacks struct timespec+ # -DHAVE_SYMLINK=0 if your system lacks the symlink function # -DHAVE_SYS_STAT_H=0 if <sys/stat.h> does not work* -# The following additional option may be needed: -# -Dmode_t=T to define mode_t to be type T +# If 0, you may also need -Dmode_t=M to define mode_t to be type M. # -DHAVE_TZSET=0 if your system lacks a tzset function # -DHAVE_UNISTD_H=0 if <unistd.h> does not work* # -DHAVE_UTMPX_H=0 if <utmpx.h> does not work* diff --git a/NEWS b/NEWS index 37ac9fba..64d32bf3 100644 --- a/NEWS +++ b/NEWS @@ -44,12 +44,13 @@ Unreleased, experimental changes no less caution than TZ strings taken from the environment, as the old undocumented behavior would have been hard to explain. tzset etc. no longer use the 'access' system call to check access; - instead they now use the system calls issetuid, getauxval, + instead they now use the system calls issetugid, getauxval, getresuid/getresgid, and geteuid/getegid/getuid/getgid (whichever first works) to test whether a program is privileged. - Compile with -DHAVE_ISSETUID=[01], -DHAVE_GETAUXVAL=[01], - -DHAVE_GETRESUID=[01], and -DHAVE_GETEUID=[01] to enable or - disable these system calls' use. + Compile with -DHAVE_SYS_AUXV_H=[01] to enable or disable + <sys/auxv.h> which (if it defines AT_SECURE) enables getauxval, + and compile with -DHAVE_ISSETUGID=[01], -DHAVE_GETRESUID=[01], and + -DHAVE_GETEUID=[01] to enable or disable the other calls' use. The new CFLAGS option -DTZ_CHANGE_INTERVAL=N makes tzset etc. check for TZif file changes if the in-memory data are N seconds diff --git a/localtime.c b/localtime.c index a8c442dd..f2d35813 100644 --- a/localtime.c +++ b/localtime.c @@ -19,10 +19,6 @@ #include "tzfile.h" #include <fcntl.h> -#if HAVE_GETAUXVAL && !HAVE_ISSETUGID -# include <sys/auxv.h> -#endif - #if HAVE_SYS_STAT_H # include <sys/stat.h> # ifndef S_ISREG @@ -366,12 +362,29 @@ static int openat(int dd, char const *path, int oflag) { unreachable (); } # define O_SEARCH 0 #endif -/* Return 1 if the process is privileged, 0 otherwise. */ #if !HAVE_ISSETUGID + +# if !defined HAVE_SYS_AUXV_H && defined __has_include +# if __has_include(<sys/auxv.h>) +# define HAVE_SYS_AUXV_H 1 +# endif +# endif +# ifndef HAVE_SYS_AUXV_H +# if defined __GLIBC__ && 2 < __GLIBC__ + (19 <= __GLIBC_MINOR__) +# define HAVE_SYS_AUXV_H 1 +# else +# define HAVE_SYS_AUXV_H 0 +# endif +# endif +# if HAVE_SYS_AUXV_H +# include <sys/auxv.h> +# endif + +/* Return 1 if the process is privileged, 0 otherwise. */ static int issetugid(void) { -# if HAVE_GETAUXVAL && defined AT_SECURE +# if HAVE_SYS_AUXV_H && defined AT_SECURE unsigned long val; errno = 0; val = getauxval(AT_SECURE); diff --git a/private.h b/private.h index 8d3d6404..4daa4864 100644 --- a/private.h +++ b/private.h @@ -294,19 +294,6 @@ extern int optind; # endif #endif -#if !defined HAVE_GETAUXVAL && defined __has_include -# if __has_include(<sys/auxv.h>) -# define HAVE_GETAUXVAL 1 -# endif -#endif -#ifndef HAVE_GETAUXVAL -# if defined __GLIBC__ && 2 < __GLIBC__ + (19 <= __GLIBC_MINOR__) -# define HAVE_GETAUXVAL 1 -# else -# define HAVE_GETAUXVAL 0 -# endif -#endif - #ifndef HAVE_ISSETUGID # if (defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \ || (defined __linux__ && !defined __GLIBC__) /* Android, musl, etc. */ \ -- 2.51.0

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[PROPOSED] Shorten GCC_INSTRUMENT à la GCC 14
by Paul Eggert Oct. 25, 2025

Oct. 25, 2025

* Makefile (GCC_INSTRUMENT): Switch from -fsanitize-undefined-trap-on-error to its shorter alias -fsanitize-trap=all, introduced in GCC 14. --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index f57042df..3b259c80 100644 --- a/Makefile +++ b/Makefile @@ -380,7 +380,7 @@ LDLIBS= # Select instrumentation via "make GCC_INSTRUMENT='whatever'". GCC_INSTRUMENT = \ -fsanitize=undefined -fsanitize-address-use-after-scope \ - -fsanitize-undefined-trap-on-error -fstack-protector + -fsanitize-trap=all -fstack-protector # Omit -fanalyzer from GCC_DEBUG_FLAGS, as it makes GCC too slow. GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \ $(GCC_INSTRUMENT) \ -- 2.51.0

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[PROPOSED 0/3] zic options -D, -m, and -u from FreeBSD
by Paul Eggert Oct. 24, 2025

Oct. 24, 2025

This thread contains proposed patches to add support for the zic options -D, -m, and -u, which have been in FreeBSD zic for many years. The implementation differs from that of FreeBSD, to fix some unlikely security races. I installed these patches in the development repository on GitHub. Paul Eggert (3): New zic option -D, inspired by FreeBSD New zic option -m, inspired by FreeBSD New zic option -u, inspired by FreeBSD Makefile | 8 ++ NEWS | 2 + zic.8 | 32 +++++++ zic.c | 259 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 4 files changed, 293 insertions(+), 8 deletions(-) -- 2.48.1

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Possible timezone change in Argentina (starting in April?)
by Mariano Absatz - el Baby Oct. 24, 2025

Oct. 24, 2025

Hi, back here after 12+ years for a heads up... There is a Law proposal approved by the Cámara de Diputados (equivalent of the House) but yet to be approved in the Senate regarding Argentina's timezone. Argentina is currently in UTC-3 with no DST. The proposal establishes the Official Time for the whole country as UTC-4 (which is geographically more accurate), with a DST of UTC-3. The DST would start at 00:00 on the first April Sunday and would end at 00:00 on the first September Sunday. The Executive is authorized to modify these dates and to coordinate with other countries of MERCOSUR to apply changes on the same moment. This is just a heads up, since the Senate did not approve or modify the proposal. If this is approved and enacted before April 2026, we can assume the current status is DST and at 00:00 Sunday April 5th 2026 we would be moving the clock back to 23:00 Saturday April 4th. I'll keep you posted as this evolves, but don't hold your breath since on October 26th there are Legislative Elections (midterm), and half of the House and one third of the Senate will change. The new legislators will take office on December 10th. By the end of December the ordinary session of Congress ends; it may be extended by the Executive Branch, but there is no certainty about which bills can be discussed. References (all in Spanish): * Law proposal (official Cámara de Diputados site): https://www.hcdn.gob.ar/diputados/jcobos/proyecto.html?exp=1110-D-2024 (click on the "Ver documento original" button) * Status in the Senate: https://www.senado.gob.ar/parlamentario/comisiones/verExp/14.25/CD/PL (click on the "Texto Original" button for the signed proposal sent from the Cámara de Diputados; click on the "Trámite Legislativo" button for the process status in the Senate) * Brief article about the proposal on a reputed fact checking site: https://chequeado.com/el-explicador/cambio-de-huso-horario-en-la-argentina-… -- Mariano Absatz - el Baby www.clueless.ar

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[PROPOSED 1/2] Refactor duplicate duplicate-option code
by Paul Eggert Oct. 24, 2025

Oct. 24, 2025

* zic.c (duplicate_options): New function. (main): Use it. --- zic.c | 73 +++++++++++++++++++---------------------------------------- 1 file changed, 23 insertions(+), 50 deletions(-) diff --git a/zic.c b/zic.c index 67bcaa43..34e7d91c 100644 --- a/zic.c +++ b/zic.c @@ -708,6 +708,13 @@ close_file(FILE *stream, char const *dir, char const *name, } } +ATTRIBUTE_NORETURN static void +duplicate_options(char const *opt) +{ + fprintf(stderr, _("%s: More than one %s option specified\n"), progname, opt); + exit(EXIT_FAILURE); +} + ATTRIBUTE_NORETURN static void usage(FILE *stream, int status) { @@ -1063,73 +1070,39 @@ main(int argc, char **argv) error(_("invalid option: -b '%s'"), optarg); break; case 'd': - if (directory == NULL) - directory = optarg; - else { - fprintf(stderr, - _("%s: More than one -d option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (directory) + duplicate_options("-d"); + directory = optarg; break; case 'l': - if (lcltime == NULL) - lcltime = optarg; - else { - fprintf(stderr, - _("%s: More than one -l option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (lcltime) + duplicate_options("-l"); + lcltime = optarg; break; case 'p': - if (psxrules == NULL) - psxrules = optarg; - else { - fprintf(stderr, - _("%s: More than one -p option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (psxrules) + duplicate_options("-p"); + psxrules = optarg; break; case 't': - if (tzdefault != NULL) { - fprintf(stderr, - _("%s: More than one -t option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (tzdefault) + duplicate_options("-t"); tzdefault = optarg; break; case 'y': warning(_("-y ignored")); break; case 'L': - if (leapsec == NULL) - leapsec = optarg; - else { - fprintf(stderr, - _("%s: More than one -L option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (leapsec) + duplicate_options("-L"); + leapsec = optarg; break; case 'v': noise = true; break; case 'r': - if (timerange_given) { - fprintf(stderr, - _("%s: More than one -r option" - " specified\n"), - progname); - return EXIT_FAILURE; - } + if (timerange_given) + duplicate_options("-r"); if (! timerange_option(optarg)) { fprintf(stderr, _("%s: invalid time range: %s\n"), -- 2.48.1

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South Africa Daylight Saving Time
by Saras Sing Oct. 21, 2025

Oct. 21, 2025

https://www.timeanddate.com/time/change/south-africa?year=1942 https://www.timeanddate.com/time/change/south-africa?year=1944 https://www.timeanddate.com/time/change/south-africa Hello South Africa has Daylight Saving Time every year from September to March South African Daylight Saving Time starts at every first Sunday of September from GMT/UTC+02:00 00:00 to 01:00 to GMT/UTC+03:00 South African Daylight Saving Time ends at every last Sunday of March from GMT/UTC+03:00 01:00 to 00:00 back to South Africa Standard Time GMT/UTC+02:00 Thank you

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[PROPOSED 1/3] zic now uses is_digit
by Paul Eggert Oct. 18, 2025

Oct. 18, 2025

Refactor zic.c to use is_digit like others use. * zic.c (is_digit): New static function, copied from localtime.c and from zdump.c. It’s too bad we can’t avoid duplication by putting this into private.h, because gcc -Wunused-function would then complain about it. Perhaps ‘inline’ would pacify gcc but then we’d have to port ‘inline’ to ancient compilers and anyway ‘inline’ is supposed to be just a performance hint which is not needed here. --- zic.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/zic.c b/zic.c index 39e1e2bc..30426621 100644 --- a/zic.c +++ b/zic.c @@ -229,6 +229,13 @@ static bool rulesub(struct rule * rp, const char * dayp, const char * timep); static zic_t tadd(zic_t t1, zic_t t2); +/* Is C an ASCII digit? */ +static bool +is_digit(char c) +{ + return '0' <= c && c <= '9'; +} + /* Bound on length of what %z can expand to. */ enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 }; @@ -1852,7 +1859,7 @@ gethms(char const *string, char const *errstring) &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs)) { default: ok = false; break; case 8: - ok = '0' <= xr && xr <= '9'; + ok = is_digit(xr); ATTRIBUTE_FALLTHROUGH; case 7: ok &= ssx == '.'; @@ -3952,7 +3959,7 @@ newabbr(const char *string) cp = string; mp = NULL; - while (is_alpha(*cp) || ('0' <= *cp && *cp <= '9') + while (is_alpha(*cp) || is_digit(*cp) || *cp == '-' || *cp == '+') ++cp; if (noise && cp - string < 3) -- 2.51.0

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[PROPOSED] New compile-time option THREAD_TM_MULTI
by Paul Eggert Oct. 14, 2025

Oct. 14, 2025

* Makefile, NEWS: Mention it. * localtime.c (THREAD_TM_MULTI): Default to 0. The remaining changes affect only the THREAD_TM_MULTI case. (enum tm_multi): New enum. (N_TM_MULTI): New constant. (tm_multi_key, tm_multi_key_err): New static vars. (tm_multi): New static function. (localtime, gmtime, offtime): Use it. --- Makefile | 8 ++++++++ NEWS | 9 +++++++++ localtime.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 3 files changed, 70 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 8939869a..b172542a 100644 --- a/Makefile +++ b/Makefile @@ -316,6 +316,14 @@ LDLIBS= # This can improve paralellism and thus save real time # if many threads call tzcode functions simultaneously. # It also costs CPU time and thus energy. +# -DTHREAD_TM_MULTI to have gmtime, localtime, and offtime +# return different struct tm * addresses in different threads. +# This supports unportable programs that call +# gmtime/localtime/offtime when they should call +# gmtime_r/localtime_r/offtime_r to avoid races. +# Because the corresponding storage is freed on thread exit, +# this option is incompatible with POSIX.1-2024 and earlier. +# It also costs CPU time and memory. # -Dtime_tz=\"T\" to use T as the time_t type, rather than the system time_t # This is intended for internal use only; it mangles external names. # -DTZ_CHANGE_INTERVAL=N if functions depending on TZ should check diff --git a/NEWS b/NEWS index 5bfb7bb4..46bf48ed 100644 --- a/NEWS +++ b/NEWS @@ -80,6 +80,15 @@ Unreleased, experimental changes rarely changing and many threads call tzcode simultaneously. It costs more CPU time and energy. + The new CFLAGS option -TTHREAD_TM_MULTI causes localtime to return + a pointer to thread-specific memory, as FreeBSD does, instead of + to the same memory in all threads. This supports unportable + programs that incorrectly use localtime instead of localtime_r. + This option affects gmtime and offtime similarly to localtime. + Because the corresponding storage is freed on thread exit, this + option is incompatible with POSIX.1-2024 and earlier. It also + costs CPU time and memory. + tzcode now uses mempcpy if available, guessing its availability. Compile with -DHAVE_MEMPCPY=1 or 0 to override the guess. diff --git a/localtime.c b/localtime.c index 1191f810..709b954c 100644 --- a/localtime.c +++ b/localtime.c @@ -52,6 +52,10 @@ struct stat { char st_ctime, st_dev, st_ino; } # define THREAD_RWLOCK 0 #endif +#ifndef THREAD_TM_MULTI +# define THREAD_TM_MULTI 0 +#endif + #if THREAD_SAFE # include <pthread.h> @@ -171,6 +175,52 @@ once(once_t *once_control, void (*init_routine)(void)) #endif } +enum tm_multi { LOCALTIME_TM_MULTI, GMTIME_TM_MULTI, OFFTIME_TM_MULTI }; + +#if THREAD_SAFE && THREAD_TM_MULTI + +enum { N_TM_MULTI = OFFTIME_TM_MULTI + 1 }; +static pthread_key_t tm_multi_key; +static int tm_multi_key_err; + +static void +tm_multi_key_init(void) +{ + tm_multi_key_err = pthread_key_create(&tm_multi_key, free); +} + +#endif + +/* Return TMP, or a thread-specific struct tm * selected by WHICH. */ +static struct tm * +tm_multi(struct tm *tmp, ATTRIBUTE_MAYBE_UNUSED enum tm_multi which) +{ +#if THREAD_SAFE && THREAD_TM_MULTI + /* It is OK to check is_threaded() separately here; even if it + returns a different value in other places in the caller, + this function's behavior is still valid. */ + if (is_threaded()) { + /* Try to get a thread-specific struct tm *. + Fall back on TMP if this fails. */ + static pthread_once_t tm_multi_once = PTHREAD_ONCE_INIT; + pthread_once(&tm_multi_once, tm_multi_key_init); + if (!tm_multi_key_err) { + struct tm *p = pthread_getspecific(tm_multi_key); + if (!p) { + p = malloc(N_TM_MULTI * sizeof *p); + if (p && pthread_setspecific(tm_multi_key, p) != 0) { + free(p); + p = NULL; + } + } + if (p) + return &p[which]; + } + } +#endif + return tmp; +} + /* Unless intptr_t is missing, pacify gcc -Wcast-qual on char const * exprs. Use this carefully, as the casts disable type checking. This is a macro so that it can be used in static initializers. */ @@ -2156,7 +2206,7 @@ localtime(const time_t *timep) # if !SUPPORT_C89 static struct tm tm; # endif - return localtime_tzset(timep, &tm, true); + return localtime_tzset(timep, tm_multi(&tm, LOCALTIME_TM_MULTI), true); } struct tm * @@ -2208,7 +2258,7 @@ gmtime(const time_t *timep) # if !SUPPORT_C89 static struct tm tm; # endif - return gmtime_r(timep, &tm); + return gmtime_r(timep, tm_multi(&tm, GMTIME_TM_MULTI)); } # if STD_INSPIRED @@ -2229,7 +2279,7 @@ offtime(time_t const *timep, long offset) # if !SUPPORT_C89 static struct tm tm; # endif - return offtime_r(timep, offset, &tm); + return offtime_r(timep, offset, tm_multi(&tm, OFFTIME_TM_MULTI)); } # endif -- 2.48.1

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[PROPOSED 1/3] Define fullname only if needed
by Paul Eggert Oct. 14, 2025

Oct. 14, 2025

* localtime.c (union local_storage): Define fullname member only if needed. This saves space on unlikely platforms where sizeof (struct file_analysis) < PATH_MAX, and is closer to FreeBSD. (tzloadbody): Mention fullname only if declared. --- localtime.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/localtime.c b/localtime.c index a78962a6..c9836b2d 100644 --- a/localtime.c +++ b/localtime.c @@ -771,7 +771,7 @@ union local_storage { struct state st; } u; -#ifdef PATH_MAX +#if defined PATH_MAX && !OPENAT_TZDIR && !SUPPRESS_TZDIR /* The name of the file to be opened. */ char fullname[PATH_MAX]; #endif @@ -890,7 +890,7 @@ tzloadbody(char const *name, struct state *sp, char tzloadflags, cp = mempcpy(lsp, tzdirslash, tzdirslashlen); cp = mempcpy(cp, name, namelen); *cp = '\0'; -#ifdef PATH_MAX +#if defined PATH_MAX && !OPENAT_TZDIR && !SUPPRESS_TZDIR name = lsp->fullname; #else name = (char *) lsp; -- 2.48.1

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