lighttpd1.4/src/stat_cache.h

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#ifndef _FILE_CACHE_H_
#define _FILE_CACHE_H_
#include "first.h"
#include <sys/stat.h>
#include "sys-time.h"
#include "base_decls.h"
#include "buffer.h"
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#include "array.h"
typedef struct stat stat_cache_st;
typedef struct stat_cache_entry {
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buffer name;
[multiple] Y2038 32-bit signed time_t mitigations Most OS platforms have already provided solutions to Y2038 32-bit signed time_t 5 - 10 years ago (or more!) Notable exceptions are Linux i686 and FreeBSD i386. Since 32-bit systems tend to be embedded systems, and since many distros take years to pick up new software, this commit aims to provide Y2038 mitigations for lighttpd running on 32-bit systems with Y2038-unsafe 32-bit signed time_t * Y2038: lighttpd 1.4.60 and later report Y2038 safety $ lighttpd -V + Y2038 support # Y2038-SAFE $ lighttpd -V - Y2038 support (unsafe 32-bit signed time_t) # Y2038-UNSAFE * Y2038: general platform info * Y2038-SAFE: lighttpd 64-bit builds on platforms using 64-bit time_t - all major 64-bit platforms (known to this author) use 64-bit time_t * Y2038-SAFE: lighttpd 32-bit builds on platforms using 64-bit time_t - Linux x32 ABI (different from i686) - FreeBSD all 32-bit and 64-bit architectures *except* 32-bit i386 - NetBSD 6.0 (released Oct 2012) all 32-bit and 64-bit architectures - OpenBSD 5.5 (released May 2014) all 32-bit and 64-bit architectures - Microsoft Windows XP and Visual Studio 2005 (? unsure ?) Another reference suggests Visual Studio 2015 defaults to 64-bit time_t - MacOS 10.15 Catalina (released 2019) drops support for 32-bit apps * Y2038-SAFE: lighttpd 32-bit builds on platforms using 32-bit unsigned time_t - e.g. OpenVMS (unknown if lighttpd builds on this platform) * Y2038-UNSAFE: lighttpd 32-bit builds on platforms using 32-bit signed time_t - Linux 32-bit (including i686) - glibc 32-bit library support not yet available for 64-bit time_t - https://sourceware.org/glibc/wiki/Y2038ProofnessDesign - Linux kernel 5.6 on 32-bit platforms does support 64-bit time_t https://itsubuntu.com/linux-kernel-5-6-to-fix-the-year-2038-issue-unix-y2k/ - https://www.gnu.org/software/libc/manual/html_node/64_002dbit-time-symbol-handling.html "Note: at this point, 64-bit time support in dual-time configurations is work-in-progress, so for these configurations, the public API only makes the 32-bit time support available. In a later change, the public API will allow user code to choose the time size for a given compilation unit." - compiling with -D_TIME_BITS=64 currently has no effect - glibc recent (Jul 2021) mailing list discussion - https://public-inbox.org/bug-gnulib/878s2ozq70.fsf@oldenburg.str.redhat.com/T/ - FreeBSD i386 - DragonFlyBSD 32-bit * Y2038 mitigations attempted on Y2038-UNSAFE platforms (32-bit signed time_t) * lighttpd prefers system monotonic clock instead of realtime clock in places where realtime clock is not required * lighttpd treats negative time_t values as after 19 Jan 2038 03:14:07 GMT * (lighttpd presumes that lighttpd will not encounter dates before 1970 during normal operation.) * lighttpd casts struct stat st.st_mtime (and st.st_*time) through uint64_t to convert negative timestamps for comparisions with 64-bit timestamps (treating negative timestamp values as after 19 Jan 2038 03:14:07 GMT) * lighttpd provides unix_time64_t (int64_t) and * lighttpd provides struct unix_timespec64 (unix_timespec64_t) (struct timespec equivalent using unix_time64_t tv_sec member) * lighttpd provides gmtime64_r() and localtime64_r() wrappers for platforms 32-bit platforms using 32-bit time_t and lighttpd temporarily shifts the year in order to use gmtime_r() and localtime_r() (or gmtime() and localtime()) from standard libraries, before readjusting year and passing struct tm to formatting functions such as strftime() * lighttpd provides TIME64_CAST() macro to cast signed 32-bit time_t to unsigned 32-bit and then to unix_time64_t * Note: while lighttpd tries handle times past 19 Jan 2038 03:14:07 GMT on 32-bit platforms using 32-bit signed time_t, underlying libraries and underlying filesystems might not behave properly after 32-bit signed time_t overflows (19 Jan 2038 03:14:08 GMT). If a given 32-bit OS does not work properly using negative time_t values, then lighttpd likely will not work properly on that system. * Other references and blogs - https://en.wikipedia.org/wiki/Year_2038_problem - https://en.wikipedia.org/wiki/Time_formatting_and_storage_bugs - http://www.lieberbiber.de/2017/03/14/a-look-at-the-year-20362038-problems-and-time-proofness-in-various-systems/
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unix_time64_t stat_ts;
int fd;
int refcnt;
#if defined(HAVE_FAM_H) || defined(HAVE_SYS_INOTIFY_H) || defined(HAVE_SYS_EVENT_H)
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void *fam_dir;
#endif
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buffer etag;
buffer content_type;
struct stat st;
} stat_cache_entry;
__attribute_cold__
int stat_cache_choose_engine (const buffer *stat_cache_string, log_error_st *errh);
struct fdevents; /* declaration */
__attribute_cold__
int stat_cache_init(struct fdevents *ev, log_error_st *errh);
__attribute_cold__
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void stat_cache_free(void);
void stat_cache_entry_refchg(void *data, int mod);
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__attribute_cold__
void stat_cache_xattrname (const char *name);
__attribute_pure__
const buffer * stat_cache_mimetype_by_ext(const array *mimetypes, const char *name, uint32_t nlen);
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#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
const buffer * stat_cache_mimetype_by_xattr(const char *name);
const buffer * stat_cache_content_type_get_by_xattr(stat_cache_entry *sce, const array *mimetypes, int use_xattr);
#define stat_cache_content_type_get(con, r) stat_cache_content_type_get_by_xattr((sce), (r)->conf.mimetypes, (r)->conf.use_xattr)
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#else
const buffer * stat_cache_content_type_get_by_ext(stat_cache_entry *sce, const array *mimetypes);
#define stat_cache_content_type_get(con, r) stat_cache_content_type_get_by_ext((sce), (r)->conf.mimetypes)
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#endif
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const buffer * stat_cache_etag_get(stat_cache_entry *sce, int flags);
void stat_cache_update_entry(const char *name, uint32_t len, struct stat *st, buffer *etagb);
void stat_cache_delete_entry(const char *name, uint32_t len);
void stat_cache_delete_dir(const char *name, uint32_t len);
void stat_cache_invalidate_entry(const char *name, uint32_t len);
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stat_cache_entry * stat_cache_get_entry(const buffer *name);
stat_cache_entry * stat_cache_get_entry_open(const buffer *name, int symlinks);
const stat_cache_st * stat_cache_path_stat(const buffer *name);
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int stat_cache_path_isdir(const buffer *name);
__attribute_cold__
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int stat_cache_path_contains_symlink(const buffer *name, log_error_st *errh);
int stat_cache_open_rdonly_fstat (const buffer *name, struct stat *st, int symlinks);
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void stat_cache_trigger_cleanup(void);
#endif