diff options
Diffstat (limited to 'src/shutdown/s6-linux-init-shutdown.c')
| -rw-r--r-- | src/shutdown/s6-linux-init-shutdown.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/src/shutdown/s6-linux-init-shutdown.c b/src/shutdown/s6-linux-init-shutdown.c new file mode 100644 index 0000000..f534944 --- /dev/null +++ b/src/shutdown/s6-linux-init-shutdown.c @@ -0,0 +1,268 @@ +/* ISC license. */ + +#include <stdint.h> +#include <string.h> +#include <unistd.h> +#include <signal.h> +#include <sys/stat.h> +#include <errno.h> +#include <time.h> +#include <utmpx.h> + +#include <skalibs/uint32.h> +#include <skalibs/types.h> +#include <skalibs/allreadwrite.h> +#include <skalibs/strerr2.h> +#include <skalibs/sgetopt.h> +#include <skalibs/sig.h> +#include <skalibs/tai.h> +#include <skalibs/djbunix.h> +#include <skalibs/djbtime.h> + +#include "defaults.h" +#include "initctl.h" +#include "hpr.h" + +#ifndef UT_NAMESIZE +#define UT_NAMESIZE 32 +#endif + +#define USAGE "s6-linux-init-shutdown [ -h | -p | -r | -k ] [ -f | -F ] [ -a ] [ -t sec ] time [ message ] or s6-linux-init-shutdown -c [ message ]" +#define dieusage() strerr_dieusage(100, USAGE) + +#define AC_FILE "/etc/shutdown.allow" +#define AC_BUFSIZE 4096 +#define AC_MAX 64 +#define AC_SHORT_MESSAGE "no authorized users logged in\n" +#define AC_MESSAGE "s6-linux-init-shutdown: " AC_SHORT_MESSAGE + + + /* shutdown 01:23: date/time format parsing */ + +static inline void add_one_day (struct tm *tm) +{ + tm->tm_isdst = -1 ; + if (tm->tm_mday++ < 31) return ; + tm->tm_mday = 1 ; + if (tm->tm_mon++ < 11) return ; + tm->tm_mon = 0 ; + tm->tm_year++ ; +} + +static inline void parse_hourmin (tain_t *when, char const *s) +{ + tai_t taithen ; + struct tm tmnow, tmthen ; + unsigned int hour, minute ; + size_t len = uint_scan(s, &hour) ; + if (!len || len > 2 || s[len] != ':' || hour > 23) + strerr_dief1x(100, "invalid time format") ; + s += len+1 ; + len = uint0_scan(s, &minute) ; + if (!len || len != 2 || minute > 59) + strerr_dief1x(100, "invalid time format") ; + if (!localtm_from_tai(&tmnow, tain_secp(&STAMP), 1)) + strerr_diefu1sys(111, "break down current time into struct tm") ; + tmthen = tmnow ; + tmthen.tm_hour = hour ; + tmthen.tm_min = minute ; + if (!tai_from_localtm(&taithen, &tmthen)) + strerr_diefu1sys(111, "assemble broken-down time into tain_t") ; + if (tai_less(&taithen, tain_secp(&STAMP))) + { + add_one_day(&tmthen) ; + if (!tai_from_localtm(&taithen, &tmthen)) + strerr_diefu1sys(111, "assemble broken-down time into tain_t") ; + } + tai_sub(tain_secp(when), &taithen, tain_secp(&STAMP)) ; + when->nano = 0 ; +} + +static inline void parse_time (tain_t *when, char const *s) +{ + if (!strcmp(s, "now")) tain_copynow(when) ; + else if (s[0] == '+') + { + unsigned int mins ; + if (!uint0_scan(s+1, &mins)) dieusage() ; + tain_addsec_g(when, mins * 60) ; + } + else if (strchr(s, ':')) parse_hourmin(when, s) ; + else + { + unsigned int mins ; + if (!uint0_scan(s, &mins)) dieusage() ; + tain_addsec_g(when, mins * 60) ; + } +} + + + /* shutdown -a: access control */ + +static inline unsigned char cclass (unsigned char c) +{ + switch (c) + { + case 0 : return 0 ; + case '\n' : return 1 ; + case '#' : return 2 ; + default : return 3 ; + } +} + +static inline unsigned int parse_authorized_users (char *buf, char const **users, unsigned int max) +{ + static unsigned char const table[3][4] = + { + { 0x03, 0x00, 0x01, 0x12 }, + { 0x03, 0x00, 0x01, 0x01 }, + { 0x23, 0x20, 0x02, 0x02 } + } ; + size_t pos = 0 ; + size_t mark = 0 ; + unsigned int n = 0 ; + unsigned int state = 0 ; + for (; state < 3 ; pos++) + { + unsigned char what = table[state][cclass(buf[pos])] ; + state = what & 3 ; + if (what & 0x10) mark = pos ; + if (what & 0x20) + { + if (n >= max) + { + char fmt[UINT32_MAX] ; + fmt[uint32_fmt(fmt, AC_MAX)] = 0 ; + strerr_warnw4x(AC_FILE, " lists more than ", fmt, " authorized users - ignoring the extra ones") ; + break ; + } + buf[pos] = 0 ; + users[n++] = buf + mark ; + } + } + return n ; +} + +static inline int match_users_with_utmp (char const *const *users, unsigned int n) +{ + setutxent() ; + for (;;) + { + struct utmpx *utx ; + errno = 0 ; + utx = getutxent() ; + if (!utx) break ; + if (utx->ut_type != USER_PROCESS) continue ; + for (unsigned int i = 0 ; i < n ; i++) + if (!strncmp(utx->ut_user, users[i], UT_NAMESIZE)) goto yes ; + } + if (errno) strerr_warnwu1sys("getutxent") ; + endutxent() ; + return 0 ; + + yes: + endutxent() ; + return 1 ; +} + +static inline void access_control (void) +{ + char buf[AC_BUFSIZE] ; + char const *users[AC_MAX] ; + unsigned int n ; + struct stat st ; + int fd = open_readb(AC_FILE) ; + if (fd == -1) + { + if (errno == ENOENT) return ; + strerr_diefu2sys(111, "open ", AC_FILE) ; + } + if (fstat(fd, &st) == -1) + strerr_diefu2sys(111, "stat ", AC_FILE) ; + if (st.st_size >= AC_BUFSIZE) + { + char fmt[UINT32_FMT] ; + fmt[uint32_fmt(fmt, AC_BUFSIZE - 1)] = 0 ; + strerr_dief4x(1, AC_FILE, " is too big: it needs to be ", fmt, " bytes or less") ; + } + if (allread(fd, buf, st.st_size) < st.st_size) + strerr_diefu2sys(111, "read ", AC_FILE) ; + fd_close(fd) ; + buf[st.st_size] = 0 ; + n = parse_authorized_users(buf, users, AC_MAX) ; + if (!n || !match_users_with_utmp(users, n)) + { + fd = open_append("/dev/console") ; + if (fd == -1) + strerr_diefu1sys(111, "open /dev/console") ; + if (allwrite(fd, AC_MESSAGE, sizeof(AC_MESSAGE) - 1) < sizeof(AC_MESSAGE) - 1) + strerr_diefu1sys(111, "write to /dev/console") ; + strerr_dief1x(1, AC_SHORT_MESSAGE) ; + } +} + + + /* main */ + +int main (int argc, char const *const *argv) +{ + unsigned int gracetime = 0 ; + int what = 0 ; + int doactl = 0 ; + int docancel = 0 ; + tain_t when ; + PROG = "s6-linux-init-shutdown" ; + + { + subgetopt_t l = SUBGETOPT_ZERO ; + for (;;) + { + int opt = subgetopt_r(argc, argv, "hprkafFct:", &l) ; + if (opt == -1) break ; + switch (opt) + { + case 'h' : what = 1 ; break ; + case 'p' : what = 2 ; break ; + case 'r' : what = 3 ; break ; + case 'k' : what = 4 ; break ; + case 'a' : doactl = 1 ; break ; + case 'f' : /* talk to the hand */ break ; + case 'F' : /* no, the other hand */ break ; + case 'c' : docancel = 1 ; break ; + case 't' : if (!uint0_scan(l.arg, &gracetime)) dieusage() ; break ; + default : strerr_dieusage(100, USAGE) ; + } + } + argc -= l.ind ; argv += l.ind ; + } + + if (geteuid()) + { + errno = EPERM ; + strerr_diefu1sys(111, "shutdown") ; + } + if (doactl) access_control() ; + if (!tain_now_g()) strerr_warnw1sys("get current time") ; + if (docancel) + { + if (argv[0]) hpr_wall(argv[0]) ; + if (!hpr_cancel()) goto err ; + return 0 ; + } + if (!argc) dieusage() ; + parse_time(&when, argv[0]) ; + if (argv[1]) hpr_wall(argv[1]) ; + if (what < 4) + { + if (gracetime > 300) + { + gracetime = 300 ; + strerr_warnw1x("delay between SIGTERM and SIGKILL is capped to 300 seconds") ; + } + if (!hpr_shutdown(what, &when, gracetime * 1000)) goto err ; + } + return 0 ; + + err: + strerr_diefu2sys(111, "write to ", INITCTL) ; +} |