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>

1 files changed, 36 insertions, 39 deletions

diff --git a/miscutils/crond.c b/miscutils/crond.c
index 06d72ced9..481830f4d 100644
--- 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 {