Windows has no utmp file. But it's possible to derive the boot time by looking at the time stamp of a file, namely C:\pagefile.sys. This is the same trick as used by Emacs (see emacs/nt/inc/ms-w32.h:BOOT_TIME_FILE).
Other ways to determine the boot time, through the event log, would also be possible: Search for event 6005 [1][2]. [1] https://serverfault.com/questions/702828/ [2] https://www.renanrodrigues.com/post/how-to-find-out-the-last-time-windows-rebooted-and-started-up [3] https://www.whatsupgold.com/blog/how-to-find-restart-info-for-machines-on-your-network-using-powershell-and-windows-event-logs 2023-08-11 Bruno Haible <br...@clisp.org> readutmp: On Cygwin and Windows, return the boot time. * lib/readutmp.h (READ_UTMP_SUPPORTED): Define also on native Windows. * lib/readutmp.c (desirable_utmp_entry): Ignore READ_UTMP_CHECK_PIDS on Windows. (read_utmp_from_file): Add a BOOT_TIME entry on Windows. diff --git a/lib/readutmp.c b/lib/readutmp.c index eabd3e7678..c19ec2f6b1 100644 --- a/lib/readutmp.c +++ b/lib/readutmp.c @@ -178,11 +178,13 @@ desirable_utmp_entry (STRUCT_UTMP const *ut, int options) bool user_proc = IS_USER_PROCESS (ut); if ((options & READ_UTMP_USER_PROCESS) && !user_proc) return false; +# if !(defined __CYGWIN__ || defined _WIN32) if ((options & READ_UTMP_CHECK_PIDS) && user_proc && 0 < UT_PID (ut) && (kill (UT_PID (ut), 0) < 0 && errno == ESRCH)) return false; +# endif return true; } @@ -359,7 +361,9 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, struct utmp_alloc a = {0}; -# if defined UTMP_NAME_FUNCTION /* glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, IRIX, Solaris, Cygwin, Android */ +# if READUTMP_USE_SYSTEMD || HAVE_UTMPX_H || HAVE_UTMP_H + +# if defined UTMP_NAME_FUNCTION /* glibc, musl, macOS, FreeBSD, NetBSD, Minix, AIX, IRIX, Solaris, Cygwin, Android */ /* Ignore the return value for now. Solaris' utmpname returns 1 upon success -- which is contrary @@ -369,17 +373,17 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, SET_UTMP_ENT (); -# if defined __linux__ && !defined __ANDROID__ +# if defined __linux__ && !defined __ANDROID__ bool file_is_utmp = (strcmp (file, UTMP_FILE) == 0); /* Timestamp of the "runlevel" entry, if any. */ struct timespec runlevel_ts = {0}; -# endif +# endif void const *entry; while ((entry = GET_UTMP_ENT ()) != NULL) { -# if __GLIBC__ && _TIME_BITS == 64 +# if __GLIBC__ && _TIME_BITS == 64 /* This is a near-copy of glibc's struct utmpx, which stops working after the year 2038. Unlike the glibc version, struct utmpx32 describes the file format even if time_t is 64 bits. */ @@ -410,9 +414,9 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, char ut_reserved[20]; /* Reserved for future use. */ }; struct utmpx32 const *ut = (struct utmpx32 const *) entry; -# else +# else struct UTMP_STRUCT_NAME const *ut = (struct UTMP_STRUCT_NAME const *) entry; -# endif +# endif struct timespec ts = #if (HAVE_UTMPX_H ? 1 : HAVE_STRUCT_UTMP_UT_TV) @@ -452,17 +456,17 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, #endif UT_EXIT_E_TERMINATION (ut), UT_EXIT_E_EXIT (ut) ); -# if defined __linux__ && !defined __ANDROID__ +# if defined __linux__ && !defined __ANDROID__ if (file_is_utmp && memcmp (UT_USER (ut), "runlevel", strlen ("runlevel") + 1) == 0 && memcmp (ut->ut_line, "~", strlen ("~") + 1) == 0) runlevel_ts = ts; -# endif +# endif } END_UTMP_ENT (); -# if defined __linux__ && !defined __ANDROID__ +# if defined __linux__ && !defined __ANDROID__ /* On Alpine Linux, UTMP_FILE is not filled. It is always empty. So, fake a BOOT_TIME entry, by getting the time stamp of a file that gets touched only during the boot process. @@ -519,9 +523,9 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, } } } -# endif +# endif -# if defined __ANDROID__ +# if defined __ANDROID__ /* On Android, there is no /var, and normal processes don't have access to system files. Therefore use the kernel's uptime counter, although it produces wrong values after the date has been bumped in the running @@ -565,9 +569,9 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, } } } -# endif +# endif -# else /* old FreeBSD, OpenBSD, HP-UX */ +# else /* old FreeBSD, OpenBSD, HP-UX */ FILE *f = fopen (file, "re"); @@ -627,7 +631,7 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, return -1; } -# if defined __OpenBSD__ +# if defined __OpenBSD__ /* On OpenBSD, UTMP_FILE is not filled. It contains only dummy entries. So, fake a BOOT_TIME entry, by getting the time stamp of a file that gets touched only during the boot process. */ @@ -661,8 +665,41 @@ read_utmp_from_file (char const *file, idx_t *n_entries, STRUCT_UTMP **utmp_buf, } } } +# endif + # endif +# endif + +# if defined __CYGWIN__ || defined _WIN32 + /* On Cygwin, /var/run/utmp is empty. + On native Windows, <utmpx.h> and <utmp.h> don't exist. + Instead, on Windows, the boot time can be retrieved by looking at the + time stamp of a file that (normally) gets touched only during the boot + process, namely C:\pagefile.sys. */ + if ((options & (READ_UTMP_USER_PROCESS | READ_UTMP_NO_BOOT_TIME)) == 0 + && strcmp (file, UTMP_FILE) == 0 + && a.filled == 0) + { + const char * const boot_touched_file = + #if defined __CYGWIN__ && !defined _WIN32 + "/cygdrive/c/pagefile.sys" + #else + "C:\\pagefile.sys" + #endif + ; + struct stat statbuf; + if (stat (boot_touched_file, &statbuf) >= 0) + { + struct timespec boot_time = get_stat_mtime (&statbuf); + a = add_utmp (a, options, + "reboot", strlen ("reboot"), + "", 0, + "", 0, + "", 0, + 0, BOOT_TIME, boot_time, 0, 0, 0); + } + } # endif a = finish_utmp (a); diff --git a/lib/readutmp.h b/lib/readutmp.h index 8db549a393..70cd3801db 100644 --- a/lib/readutmp.h +++ b/lib/readutmp.h @@ -243,7 +243,7 @@ enum { UT_HOST_SIZE = -1 }; || (UT_TYPE_NOT_DEFINED && UT_TIME_MEMBER (UT) != 0))) /* Define if read_utmp is not just a dummy. */ -#if READUTMP_USE_SYSTEMD || HAVE_UTMPX_H || HAVE_UTMP_H +#if READUTMP_USE_SYSTEMD || HAVE_UTMPX_H || HAVE_UTMP_H || defined __CYGWIN__ || defined _WIN32 # define READ_UTMP_SUPPORTED 1 #endif
