crond: check mtime on crontab dir every minute, and reread if changed

function                                             old     new   delta
crond_main                                          1417    1460     +43

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/miscutils/crond.c b/miscutils/crond.c
index 06d72ced9f69f4a05b91ab883a0939295aab1ff7..481830f4d61751dc26c7c146f0dd0d1e95cb6e09 100644 (file)
--- a/miscutils/crond.c
+++ b/miscutils/crond.c
@@ -87,6 +87,7 @@ enum {
 
 struct globals {
        unsigned LogLevel; /* = 8; */
+       time_t CDir_mtime;
        const char *LogFile;
        const char *CDir; /* = CRONTABS; */
        CronFile *FileBase;
@@ -96,15 +97,9 @@ struct globals {
 #endif
 } FIX_ALIASING;
 #define G (*(struct globals*)&bb_common_bufsiz1)
-#define LogLevel           (G.LogLevel               )
-#define LogFile            (G.LogFile                )
-#define CDir               (G.CDir                   )
-#define FileBase           (G.FileBase               )
-#define env_var_user       (G.env_var_user           )
-#define env_var_home       (G.env_var_home           )
 #define INIT_G() do { \
-       LogLevel = 8; \
-       CDir = CRONTABS; \
+       G.LogLevel = 8; \
+       G.CDir = CRONTABS; \
 } while (0)
 
 
@@ -124,12 +119,12 @@ static void crondlog(const char *ctl, ...)
        int level = (ctl[0] & 0x1f);
 
        va_start(va, ctl);
-       if (level >= (int)LogLevel) {
+       if (level >= (int)G.LogLevel) {
                /* Debug mode: all to (non-redirected) stderr, */
                /* Syslog mode: all to syslog (logmode = LOGMODE_SYSLOG), */
-               if (!DebugOpt && LogFile) {
+               if (!DebugOpt && G.LogFile) {
                        /* Otherwise (log to file): we reopen log file at every write: */
-                       int logfd = open3_or_warn(LogFile, O_WRONLY | O_CREAT | O_APPEND, 0666);
+                       int logfd = open3_or_warn(G.LogFile, O_WRONLY | O_CREAT | O_APPEND, 0666);
                        if (logfd >= 0)
                                xmove_fd(logfd, STDERR_FILENO);
                }
@@ -168,10 +163,10 @@ static void safe_setenv(char **pvar_val, const char *var, const char *val)
 static void SetEnv(struct passwd *pas)
 {
 #if SETENV_LEAKS
-       safe_setenv(&env_var_user, "USER", pas->pw_name);
-       safe_setenv(&env_var_home, "HOME", pas->pw_dir);
+       safe_setenv(&G.env_var_user, "USER", pas->pw_name);
+       safe_setenv(&G.env_var_home, "HOME", pas->pw_dir);
        /* if we want to set user's shell instead: */
-       /*safe_setenv(env_var_shell, "SHELL", pas->pw_shell);*/
+       /*safe_setenv(G.env_var_shell, "SHELL", pas->pw_shell);*/
 #else
        xsetenv("USER", pas->pw_name);
        xsetenv("HOME", pas->pw_dir);
@@ -308,7 +303,7 @@ static void ParseField(char *user, char *ary, int modvalue, int off,
                return;
        }
 
-       if (DebugOpt && (LogLevel <= 5)) { /* like LVL5 */
+       if (DebugOpt && (G.LogLevel <= 5)) { /* like LVL5 */
                /* can't use crondlog, it inserts '\n' */
                int i;
                for (i = 0; i < modvalue; ++i)
@@ -351,7 +346,7 @@ static void FixDayDow(CronLine *line)
  */
 static void DeleteFile(const char *userName)
 {
-       CronFile **pfile = &FileBase;
+       CronFile **pfile = &G.FileBase;
        CronFile *file;
 
        while ((file = *pfile) != NULL) {
@@ -462,8 +457,8 @@ static void SynchronizeFile(const char *fileName)
                }
                *pline = NULL;
 
-               file->cf_Next = FileBase;
-               FileBase = file;
+               file->cf_Next = G.FileBase;
+               G.FileBase = file;
 
                if (maxLines == 0) {
                        crondlog(WARN9 "user %s: too many lines", fileName);
@@ -493,7 +488,7 @@ static void SynchronizeDir(void)
        CronFile *file;
        /* Attempt to delete the database. */
  again:
-       for (file = FileBase; file; file = file->cf_Next) {
+       for (file = G.FileBase; file; file = file->cf_Next) {
                if (!file->cf_Deleted) {
                        DeleteFile(file->cf_User);
                        goto again;
@@ -509,8 +504,8 @@ static void SynchronizeDir(void)
         * scan directory and add associated users
         */
        unlink(CRONUPDATE);
-       if (chdir(CDir) < 0) {
-               crondlog(DIE9 "chdir(%s)", CDir);
+       if (chdir(G.CDir) < 0) {
+               crondlog(DIE9 "chdir(%s)", G.CDir);
        }
        {
                DIR *dir = opendir(".");
@@ -537,9 +532,8 @@ static void SynchronizeDir(void)
  * period is about a minute (one scan).  Worst case it will be one
  * hour (60 scans).
  */
-static int TestJobs(time_t t1, time_t t2)
+static void TestJobs(time_t t1, time_t t2)
 {
-       int nJobs = 0;
        time_t t;
 
        /* Find jobs > t1 and <= t2 */
@@ -553,7 +547,7 @@ static int TestJobs(time_t t1, time_t t2)
                        continue;
 
                ptm = localtime(&t);
-               for (file = FileBase; file; file = file->cf_Next) {
+               for (file = G.FileBase; file; file = file->cf_Next) {
                        if (DebugOpt)
                                crondlog(LVL5 "file %s:", file->cf_User);
                        if (file->cf_Deleted)
@@ -575,13 +569,11 @@ static int TestJobs(time_t t1, time_t t2)
                                        } else if (line->cl_Pid == 0) {
                                                line->cl_Pid = -1;
                                                file->cf_Ready = 1;
-                                               ++nJobs;
                                        }
                                }
                        }
                }
        }
-       return nJobs;
 }
 
 #if ENABLE_FEATURE_CROND_CALL_SENDMAIL
@@ -650,7 +642,7 @@ static int CheckJobs(void)
        CronLine *line;
        int nStillRunning = 0;
 
-       for (file = FileBase; file; file = file->cf_Next) {
+       for (file = G.FileBase; file; file = file->cf_Next) {
                if (file->cf_Running) {
                        file->cf_Running = 0;
 
@@ -819,7 +811,7 @@ static void RunJobs(void)
        CronFile *file;
        CronLine *line;
 
-       for (file = FileBase; file; file = file->cf_Next) {
+       for (file = G.FileBase; file; file = file->cf_Next) {
                if (!file->cf_Ready)
                        continue;
 
@@ -854,9 +846,9 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
        opt_complementary = "f-b:b-f:S-L:L-S" IF_FEATURE_CROND_D(":d-l")
                        ":l+:d+"; /* -l and -d have numeric param */
        opts = getopt32(argv, "l:L:fbSc:" IF_FEATURE_CROND_D("d:"),
-                       &LogLevel, &LogFile, &CDir
-                       IF_FEATURE_CROND_D(,&LogLevel));
-       /* both -d N and -l N set the same variable: LogLevel */
+                       &G.LogLevel, &G.LogFile, &G.CDir
+                       IF_FEATURE_CROND_D(,&G.LogLevel));
+       /* both -d N and -l N set the same variable: G.LogLevel */
 
        if (!(opts & OPT_f)) {
                /* close stdin, stdout, stderr.
@@ -864,30 +856,32 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
                bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
        }
 
-       if (!(opts & OPT_d) && LogFile == NULL) {
+       if (!(opts & OPT_d) && G.LogFile == NULL) {
                /* logging to syslog */
                openlog(applet_name, LOG_CONS | LOG_PID, LOG_CRON);
                logmode = LOGMODE_SYSLOG;
        }
 
-       xchdir(CDir);
+       xchdir(G.CDir);
        //signal(SIGHUP, SIG_IGN); /* ? original crond dies on HUP... */
        xsetenv("SHELL", DEFAULT_SHELL); /* once, for all future children */
-       crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", LogLevel);
+       crondlog(LVL8 "crond (busybox "BB_VER") started, log level %d", G.LogLevel);
        SynchronizeDir();
        write_pidfile("/var/run/crond.pid");
 
-       /* main loop - synchronize to 1 second after the minute, minimum sleep
-        * of 1 second. */
+       /* Main loop */
        t2 = time(NULL);
        rescan = 60;
        sleep_time = 60;
        for (;;) {
+               struct stat sbuf;
                time_t t1;
                long dt;
 
                t1 = t2;
-               sleep((sleep_time + 1) - (time(NULL) % sleep_time));
+
+               /* Synchronize to 1 minute, minimum 1 second */
+               sleep(sleep_time - (time(NULL) % sleep_time) + 1);
 
                t2 = time(NULL);
                dt = (long)t2 - (long)t1;
@@ -908,6 +902,10 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
                 * When running jobs, the inequality used is greater but not
                 * equal to t1, and less then or equal to t2.
                 */
+               if (stat(G.CDir, &sbuf) == 0 && G.CDir_mtime != sbuf.st_mtime) {
+                       G.CDir_mtime = sbuf.st_mtime;
+                       rescan = 1;
+               }
                if (--rescan == 0) {
                        rescan = 60;
                        SynchronizeDir();
@@ -919,10 +917,9 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
                        crondlog(WARN9 "time disparity of %ld minutes detected", dt / 60);
                        /* and we do not run any jobs in this case */
                } else if (dt > 0) {
-                       /* Usual case: time advances forwad, as expected */
+                       /* Usual case: time advances forward, as expected */
                        TestJobs(t1, t2);
                        RunJobs();
-                       sleep(5);
                        if (CheckJobs() > 0) {
                                sleep_time = 10;
                        } else {