/*      $NetBSD: misc.c,v 1.5 2017/08/17 08:53:00 christos Exp $        */

/* Copyright 1988,1990,1993,1994 by Paul Vixie
* All rights reserved
*/

/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1997,2000 by Internet Software Consortium, Inc.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/cdefs.h>
#if !defined(lint) && !defined(LINT)
#if 0
static char rcsid[] = "Id: misc.c,v 1.16 2004/01/23 18:56:43 vixie Exp";
#else
__RCSID("$NetBSD: misc.c,v 1.5 2017/08/17 08:53:00 christos Exp $");
#endif
#endif

/* vix 26jan87 [RCS has the rest of the log]
* vix 30dec86 [written]
*/

#include "cron.h"
#include <limits.h>
#include <vis.h>

#if defined(SYSLOG) && defined(LOG_FILE)
# undef LOG_FILE
#endif

#if defined(LOG_DAEMON) && !defined(LOG_CRON)
# define LOG_CRON LOG_DAEMON
#endif

#ifndef FACILITY
#define FACILITY LOG_CRON
#endif

static int LogFD = ERR;

#if defined(SYSLOG)
static int syslog_open = FALSE;
#endif

static void mkprint(char *, char *, size_t);

/*
* glue_strings is the overflow-safe equivalent of
*              sprintf(buffer, "%s%c%s", a, separator, b);
*
* returns 1 on success, 0 on failure.  'buffer' MUST NOT be used if
* glue_strings fails.
*/
int
glue_strings(char *buffer, size_t buffer_size, const char *a, const char *b,
            char separator)
{
       char *buf;
       char *buf_end;

       if (buffer_size == 0)
               return (0);
       buf_end = buffer + buffer_size;
       buf = buffer;

       for ( /* nothing */; buf < buf_end && *a != '\0'; buf++, a++ )
               *buf = *a;
       if (buf == buf_end)
               return (0);
       if (separator != '/' || buf == buffer || buf[-1] != '/')
               *buf++ = separator;
       if (buf == buf_end)
               return (0);
       for ( /* nothing */; buf < buf_end && *b != '\0'; buf++, b++ )
               *buf = *b;
       if (buf == buf_end)
               return (0);
       *buf = '\0';
       return (1);
}

int
strcmp_until(const char *left, const char *right, char until) {
       while (*left && *left != until && *left == *right) {
               left++;
               right++;
       }

       if ((*left=='\0' || *left == until) &&
           (*right=='\0' || *right == until)) {
               return (0);
       }
       return (*left - *right);
}

#ifdef notdef
/* strdtb(s) - delete trailing blanks in string 's' and return new length
*/
int
strdtb(char *s) {
       char    *x = s;

       /* scan forward to the null
        */
       while (*x)
               x++;

       /* scan backward to either the first character before the string,
        * or the last non-blank in the string, whichever comes first.
        */
       do      {x--;}
       while (x >= s && isspace((unsigned char)*x));

       /* one character beyond where we stopped above is where the null
        * goes.
        */
       *++x = '\0';

       /* the difference between the position of the null character and
        * the position of the first character of the string is the length.
        */
       return (int)(x - s);
}
#endif

int
set_debug_flags(const char *flags) {
       /* debug flags are of the form    flag[,flag ...]
        *
        * if an error occurs, print a message to stdout and return FALSE.
        * otherwise return TRUE after setting ERROR_FLAGS.
        */

#if !DEBUGGING

       printf("this program was compiled without debugging enabled\n");
       return (FALSE);

#else /* DEBUGGING */

       const char *pc = flags;

       DebugFlags = 0;

       while (*pc) {
               const char      * const *test;
               int             mask;

               /* try to find debug flag name in our list.
                */
               for (test = DebugFlagNames, mask = 1;
                    *test != NULL && strcmp_until(*test, pc, ',');
                    test++, mask <<= 1)
                       continue;

               if (!*test) {
                       warnx("unrecognized debug flag <%s> <%s>\n", flags, pc);
                       return (FALSE);
               }

               DebugFlags |= mask;

               /* skip to the next flag
                */
               while (*pc && *pc != ',')
                       pc++;
               if (*pc == ',')
                       pc++;
       }

       if (DebugFlags) {
               int flag;

               (void)fprintf(stderr, "debug flags enabled:");

               for (flag = 0;  DebugFlagNames[flag];  flag++)
                       if (DebugFlags & (1 << flag))
                               (void)fprintf(stderr, " %s", DebugFlagNames[flag]);
               (void)fprintf(stderr, "\n");
       }

       return (TRUE);

#endif /* DEBUGGING */
}

void
set_cron_uid(void) {
#if defined(BSD) || defined(POSIX)
       if (seteuid(ROOT_UID) < OK) {
               err(ERROR_EXIT, "cannot seteuid");
       }
#else
       if (setuid(ROOT_UID) < OK) {
               err(ERROR_EXIT, "cannot setuid");
       }
#endif
}

void
set_cron_cwd(void) {
       struct stat sb;
       struct group *grp = NULL;

#ifdef CRON_GROUP
       grp = getgrnam(CRON_GROUP);
#endif
       /* first check for CRONDIR ("/var/cron" or some such)
        */
#ifdef ENABLE_FIX_DIRECTORIES
       if (stat(CRONDIR, &sb) < OK && errno == ENOENT) {
               warn("Cannot stat `%s'", CRONDIR);
               if (OK == mkdir(CRONDIR, 0710)) {
                       (void)fprintf(stderr, "%s: created\n", CRONDIR);
                       if (stat(CRONDIR, &sb) == -1)
                               err(ERROR_EXIT, "cannot stat `%s'", CRONDIR);
               } else {
                       err(ERROR_EXIT, "cannot create `%s'", CRONDIR);
               }
       }
       if (!S_ISDIR(sb.st_mode)) {
               errx(ERROR_EXIT, "`%s' is not a directory, bailing out.",
                       CRONDIR);
       }
#endif /* ENABLE_FIX_DIRECTORIES */
       if (chdir(CRONDIR) < OK) {
               err(ERROR_EXIT, "cannot chdir `%s', bailing out.\n", CRONDIR);
       }

       /* CRONDIR okay (now==CWD), now look at SPOOL_DIR ("tabs" or some such)
        */
#ifdef ENABLE_FIX_DIRECTORIES
       if (stat(SPOOL_DIR, &sb) < OK && errno == ENOENT) {
               warn("cannot stat `%s'", SPOOL_DIR);
               if (OK == mkdir(SPOOL_DIR, 0700)) {
                       (void)fprintf(stderr, "%s: created\n", SPOOL_DIR);
                       if (stat(SPOOL_DIR, &sb) == -1)
                               err(ERROR_EXIT, "cannot stat `%s'", CRONDIR);
               } else {
                       err(ERROR_EXIT, "cannot create `%s'", SPOOL_DIR);
               }
       }
#else
       if (stat(SPOOL_DIR, &sb)) {
               err(ERROR_EXIT, "cannot stat `%s'", SPOOL_DIR);
       }
#endif /* ENABLE_FIX_DIRECTORIES */
       if (!S_ISDIR(sb.st_mode)) {
               errx(ERROR_EXIT, "`%s' is not a directory, bailing out.",
                       SPOOL_DIR);
       }
       if (grp != NULL) {
               if (sb.st_gid != grp->gr_gid) {
#ifdef ENABLE_FIX_DIRECTORIES
                       errx(ERROR_EXIT, "Bad group %d != %d for `%s'",
                           (int)sb.st_gid, (int)grp->gr_gid, SPOOL_DIR);
#else
                       if (chown(SPOOL_DIR, (uid_t)-1, grp->gr_gid) == -1)
                           err(ERROR_EXIT, "cannot chown `%s'", SPOOL_DIR);
#endif
               }
               if (sb.st_mode != 01730)
#ifdef ENABLE_FIX_DIRECTORIES
                       errx(ERROR_EXIT, "Bad mode %#o != %#o for `%s'",
                           (int)sb.st_mode, 01730, SPOOL_DIR);
#else
                       if (chmod(SPOOL_DIR, 01730) == -1)
                           err(ERROR_EXIT, "cannot chmod `%s'", SPOOL_DIR);
#endif
       }
}

/* acquire_daemonlock() - write our PID into /etc/cron.pid, unless
*      another daemon is already running, which we detect here.
*
* note: main() calls us twice; once before forking, once after.
*      we maintain static storage of the file pointer so that we
*      can rewrite our PID into _PATH_CRON_PID after the fork.
*/
void
acquire_daemonlock(int closeflag) {
       static int fd = -1;
       char buf[3*MAX_FNAME];
       const char *pidfile;
       char *ep;
       long otherpid;
       ssize_t num;

       if (closeflag) {
               /* close stashed fd for child so we don't leak it. */
               if (fd != -1) {
                       (void)close(fd);
                       fd = -1;
               }
               return;
       }

       if (fd == -1) {
               pidfile = _PATH_CRON_PID;
               /* Initial mode is 0600 to prevent flock() race/DoS. */
               if ((fd = open(pidfile, O_RDWR|O_CREAT, 0600)) == -1) {
                       log_itx("CRON", getpid(), "DEATH",
                           "can't open or create %s: %s",
                           pidfile, strerror(errno));
                       exit(ERROR_EXIT);
               }
               /* fd must be > STDERR since we dup fd 0-2 to /dev/null */
               if (fd <= STDERR) {
                       if (dup2(fd, STDERR + 1) < 0) {
                               log_itx("CRON", getpid(), "DEATH",
                                   "can't dup pid fd: %s", strerror(errno));
                               exit(ERROR_EXIT);
                       }
                       close(fd);
                       fd = STDERR + 1;
               }

               if (flock(fd, LOCK_EX|LOCK_NB) < OK) {
                       int save_errno = errno;

                       memset(buf, 0, sizeof(buf));
                       if ((num = read(fd, buf, sizeof(buf) - 1)) > 0 &&
                           (otherpid = strtol(buf, &ep, 10)) > 0 &&
                           ep != buf && *ep == '\n' && otherpid != LONG_MAX) {
                               log_itx("CRON", getpid(), "DEATH",
                                   "can't lock %s, otherpid may be %ld: %s",
                                   pidfile, otherpid, strerror(save_errno));
                       } else {
                               log_itx("CRON", getpid(), "DEATH",
                                   "can't lock %s, otherpid unknown: %s",
                                   pidfile, strerror(save_errno));
                       }
                       exit(ERROR_EXIT);
               }
               (void) fchmod(fd, 0644);
               (void) fcntl(fd, F_SETFD, 1);
       }

       (void)snprintf(buf, sizeof(buf), "%ld\n", (long)getpid());
       (void) lseek(fd, (off_t)0, SEEK_SET);
       num = write(fd, buf, strlen(buf));
       (void) ftruncate(fd, num);

       /* abandon fd even though the file is open. we need to keep
        * it open and locked, but we don't need the handles elsewhere.
        */
}

/* get_char(file) : like getc() but increment LineNumber on newlines
*/
int
get_char(FILE *file) {
       int ch;

       ch = getc(file);
       if (ch == '\n')
               Set_LineNum(LineNumber + 1);
       return (ch);
}

/* unget_char(ch, file) : like ungetc but do LineNumber processing
*/
void
unget_char(int ch, FILE *file) {
       (void)ungetc(ch, file);
       if (ch == '\n')
               Set_LineNum(LineNumber - 1);
}

/* get_string(str, max, file, termstr) : like fgets() but
*              (1) has terminator string which should include \n
*              (2) will always leave room for the null
*              (3) uses get_char() so LineNumber will be accurate
*              (4) returns EOF or terminating character, whichever
*/
int
get_string(char *string, int size, FILE *file, const char *terms) {
       int ch;

       while (EOF != (ch = get_char(file)) && !strchr(terms, ch)) {
               if (size > 1) {
                       *string++ = (char) ch;
                       size--;
               }
       }

       if (size > 0)
               *string = '\0';

       return (ch);
}

/* skip_comments(file) : read past comment (if any)
*/
void
skip_comments(FILE *file) {
       int ch;

       while (EOF != (ch = get_char(file))) {
               /* ch is now the first character of a line.
                */

               while (ch == ' ' || ch == '\t')
                       ch = get_char(file);

               if (ch == EOF)
                       break;

               /* ch is now the first non-blank character of a line.
                */

               if (ch != '\n' && ch != '#')
                       break;

               /* ch must be a newline or comment as first non-blank
                * character on a line.
                */

               while (ch != '\n' && ch != EOF)
                       ch = get_char(file);

               /* ch is now the newline of a line which we're going to
                * ignore.
                */
       }
       if (ch != EOF)
               unget_char(ch, file);
}

void
log_itx(const char *username, PID_T xpid, const char *event, const char *fmt,
   ...)
{
       char *detail;
       va_list ap;
       va_start(ap, fmt);
       if (vasprintf(&detail, fmt, ap) == -1) {
               va_end(ap);
               return;
       }
       log_it(username, xpid, event, detail);
       free(detail);
}

void
log_it(const char *username, PID_T xpid, const char *event, const char *detail) {
#if defined(LOG_FILE) || DEBUGGING
       PID_T pid = xpid;
#endif
#if defined(LOG_FILE)
       char *msg;
       int msglen;
       TIME_T now = time((TIME_T) 0);
       struct tm *t = localtime(&now);

       if (LogFD < OK) {
               LogFD = open(LOG_FILE, O_WRONLY|O_APPEND|O_CREAT, 0600);
               if (LogFD < OK) {
                       warn("can't open log file `%s'", LOG_FILE);
               } else {
                       (void) fcntl(LogFD, F_SETFD, FD_CLOEXEC);
               }
       }

       /* we have to sprintf() it because fprintf() doesn't always write
        * everything out in one chunk and this has to be atomically appended
        * to the log file.
        */
       msglen = asprintf(&msg,
           "%s (%02d/%02d-%02d:%02d:%02d-%d) %s (%s)\n", username,
           t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, pid,
           event, detail);
       if (msglen == -1)
               return;

       if (LogFD < OK || write(LogFD, msg, (size_t)msglen) < OK) {
               warn("can't write to log file");
               write(STDERR, msg, (size_t)msglen);
       }

       free(msg);
#endif /*LOG_FILE*/

#if defined(SYSLOG)
       if (!syslog_open) {
# ifdef LOG_DAEMON
               openlog(getprogname(), LOG_PID, FACILITY);
# else
               openlog(getprogname(), LOG_PID);
# endif
               syslog_open = TRUE;             /* assume openlog success */
       }

       syslog(LOG_INFO, "(%s) %s (%s)", username, event, detail);

#endif /*SYSLOG*/

#if DEBUGGING
       if (DebugFlags) {
               (void)fprintf(stderr, "log_it: (%s %ld) %s (%s)\n",
                       username, (long)pid, event, detail);
       }
#endif
}

void
log_close(void) {
       if (LogFD != ERR) {
               (void)close(LogFD);
               LogFD = ERR;
       }
#if defined(SYSLOG)
       closelog();
       syslog_open = FALSE;
#endif /*SYSLOG*/
}

/* warning:
*      heavily ascii-dependent.
*/
static void
mkprint(char *dst, char *src, size_t len)
{
       while(len > 0 && isblank((unsigned char) *src))
               len--, src++;

       (void)strvisx(dst, src, len, VIS_TAB|VIS_NL);
}

/* warning:
*      returns a pointer to malloc'd storage, you must call free yourself.
*/
char *
mkprints(char *src, size_t len)
{
       char *dst = malloc(len*4 + 1);

       if (dst)
               mkprint(dst, src, len);

       return (dst);
}

#ifdef MAIL_DATE
/* Sat, 27 Feb 1993 11:44:51 -0800 (CST)
* 1234567890123456789012345678901234567
*/
char *
arpadate(time_t *clock)
{
       time_t t = clock ? *clock : time((TIME_T) 0);
       struct tm tm = *localtime(&t);
       long gmtoff = get_gmtoff(&t, &tm);
       int hours = gmtoff / SECONDS_PER_HOUR;
       int minutes = (gmtoff - (hours * SECONDS_PER_HOUR)) / SECONDS_PER_MINUTE;
       static char ret[64];    /* zone name might be >3 chars */

       if (minutes < 0)
               minutes = -minutes;

       (void)strftime(ret, sizeof(ret), "%a, %e %b %Y %T ????? (%Z)", &tm);
       (void)snprintf(strchr(ret, '?'), "% .2d%.2d", hours, minutes);
       ret[sizeof(ret) - 1] = '\0';
       return ret;
}
#endif /*MAIL_DATE*/

size_t
strlens(const char *last, ...) {
       va_list ap;
       size_t ret = 0;
       const char *str;

       va_start(ap, last);
       for (str = last; str != NULL; str = va_arg(ap, const char *))
               ret += strlen(str);
       va_end(ap);
       return (ret);
}

/* Return the offset from GMT in seconds (algorithm taken from sendmail).
*
* warning:
*      clobbers the static storage space used by localtime() and gmtime().
*      If the local pointer is non-NULL it *must* point to a local copy.
*/
#ifndef HAVE_TM_GMTOFF
long get_gmtoff(time_t *clock, struct tm *local)
{
       struct tm gmt;
       long offset;

       gmt = *gmtime(clock);
       if (local == NULL)
               local = localtime(clock);

       offset = (local->tm_sec - gmt.tm_sec) +
           ((local->tm_min - gmt.tm_min) * 60) +
           ((local->tm_hour - gmt.tm_hour) * 3600);

       /* Timezone may cause year rollover to happen on a different day. */
       if (local->tm_year < gmt.tm_year)
               offset -= 24 * 3600;
       else if (local->tm_year > gmt.tm_year)
               offset -= 24 * 3600;
       else if (local->tm_yday < gmt.tm_yday)
               offset -= 24 * 3600;
       else if (local->tm_yday > gmt.tm_yday)
               offset += 24 * 3600;

       return (offset);
}
#endif /* HAVE_TM_GMTOFF */

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