diff options
| -rw-r--r-- | miscutils/last.c | 47 |
1 files changed, 40 insertions, 7 deletions
diff --git a/miscutils/last.c b/miscutils/last.c index ef41444c5..2199d7524 100644 --- a/miscutils/last.c +++ b/miscutils/last.c @@ -32,12 +32,32 @@ #else +#if EMPTY != 0 || RUN_LVL != 1 || BOOT_TIME != 2 || NEW_TIME != 3 || \ + OLD_TIME != 4 +#error Values for the ut_type field of struct utmp changed +#endif + int last_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int last_main(int argc, char **argv ATTRIBUTE_UNUSED) { struct utmp ut; int n, file = STDIN_FILENO; time_t t_tmp; + off_t pos; + static const char _ut_usr[] ALIGN1 = + "runlevel\0" "reboot\0" "shutdown\0"; + static const char _ut_lin[] ALIGN1 = + "~\0" "{\0" "|\0" /* "LOGIN\0" "date\0" */; + enum { + TYPE_RUN_LVL = RUN_LVL, /* 1 */ + TYPE_BOOT_TIME = BOOT_TIME, /* 2 */ + TYPE_SHUTDOWN_TIME = SHUTDOWN_TIME + }; + enum { + _TILDE = EMPTY, /* 0 */ + TYPE_NEW_TIME, /* NEW_TIME, 3 */ + TYPE_OLD_TIME /* OLD_TIME, 4 */ + }; if (argc > 1) { bb_show_usage(); @@ -46,23 +66,33 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED) printf("%-10s %-14s %-18s %-12.12s %s\n", "USER", "TTY", "HOST", "LOGIN", "TIME"); + /* yikes. We reverse over the file and that is a not too elegant way */ + pos = xlseek(file, 0, SEEK_END); + pos = lseek(file, pos - sizeof(ut), SEEK_SET); while ((n = full_read(file, &ut, sizeof(ut))) > 0) { if (n != sizeof(ut)) { bb_perror_msg_and_die("short read"); } - - if (ut.ut_line[0] == '~') { + n = index_in_strings(_ut_lin, ut.ut_line); + if (n == _TILDE) { /* '~' */ +#if 1 +/* do we really need to be cautious here? */ + n = index_in_strings(_ut_usr, ut.ut_user); + if (++n > 0) + ut.ut_type = n; +#else if (strncmp(ut.ut_user, "shutdown", 8) == 0) ut.ut_type = SHUTDOWN_TIME; else if (strncmp(ut.ut_user, "reboot", 6) == 0) ut.ut_type = BOOT_TIME; else if (strncmp(ut.ut_user, "runlevel", 8) == 0) ut.ut_type = RUN_LVL; +#endif } else { if (ut.ut_name[0] == '\0' || strcmp(ut.ut_name, "LOGIN") == 0) { /* Don't bother. This means we can't find how long * someone was logged in for. Oh well. */ - continue; + goto next; } if (ut.ut_type != DEAD_PROCESS && ut.ut_name[0] && ut.ut_line[0] @@ -70,10 +100,10 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED) ut.ut_type = USER_PROCESS; } if (strcmp(ut.ut_name, "date") == 0) { - if (ut.ut_line[0] == '|') { + if (n == TYPE_OLD_TIME) { /* '|' */ ut.ut_type = OLD_TIME; } - if (ut.ut_line[0] == '{') { + if (n == TYPE_NEW_TIME) { /* '{' */ ut.ut_type = NEW_TIME; } } @@ -85,15 +115,18 @@ int last_main(int argc, char **argv ATTRIBUTE_UNUSED) case NEW_TIME: case RUN_LVL: case SHUTDOWN_TIME: - continue; + goto next; case BOOT_TIME: strcpy(ut.ut_line, "system boot"); - break; } } t_tmp = (time_t)ut.ut_tv.tv_sec; printf("%-10s %-14s %-18s %-12.12s\n", ut.ut_user, ut.ut_line, ut.ut_host, ctime(&t_tmp) + 4); + next: + if (!pos) + break; /* done. */ + pos = lseek(file, pos - sizeof(ut), SEEK_SET); } fflush_stdout_and_exit(EXIT_SUCCESS); |