toys/pending/crontab.c - third_party/toybox - Git at Google

 /* crontab.c - files used to schedule the execution of programs.
  *
  * Copyright 2014 Ranjan Kumar <ranjankumar.bth@gmail.com>
  *
  * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/crontab.html

 USE_CRONTAB(NEWTOY(crontab, "c:u:elr[!elr]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))

 config CRONTAB
   bool "crontab"
   default n
   help
     usage: crontab [-u user] FILE
                    [-u user] [-e | -l | -r]
                    [-c dir]

     Files used to schedule the execution of programs.

     -c crontab dir
     -e edit user's crontab
     -l list user's crontab
     -r delete user's crontab
     -u user
     FILE Replace crontab by FILE ('-': stdin)
 */
 #define FOR_crontab
 #include "toys.h"

 GLOBALS(
   char *user;
   char *cdir;
 )

 static char *omitspace(char *line)
 {
   while (*line == ' ' || *line == '\t') line++;
   return line;
 }

 /*
  * Names can also be used for the 'month' and 'day of week' fields
  * (First three letters of the particular day or month).
  */
 static int getindex(char *src, int size)
 {
   int i;
   char days[]={"sun""mon""tue""wed""thu""fri""sat"};
   char months[]={"jan""feb""mar""apr""may""jun""jul"
     "aug""sep""oct""nov""dec"};
   char *field = (size == 12) ? months : days;

   // strings are not allowed for min, hour and dom fields.
   if (!(size == 7 || size == 12)) return -1;

   for (i = 0; field[i]; i += 3) {
     if (!strncasecmp(src, &field[i], 3))
       return (i/3);
   }
   return -1;
 }

 static long getval(char *num, long low, long high)
 {
   long val = strtol(num, &num, 10);

   if (*num || (val < low) || (val > high)) return -1;
   return val;
 }

 // Validate minute, hour, day of month, month and day of week fields.
 static int validate_component(int min, int max, char *src)
 {
   int skip = 0;
   char *ptr;

   if (!src) return 1;
   if ((ptr = strchr(src, '/'))) {
     *ptr++ = 0;
     if ((skip = getval(ptr, min, (min ? max: max-1))) < 0) return 1;
   }

   if (*src == '-' || *src == ',') return 1;
   if (*src == '*') {
     if (*(src+1)) return 1;
   }
   else {
     for (;;) {
       char *ctoken = strsep(&src, ","), *dtoken;

       if (!ctoken) break;
       if (!*ctoken) return 1;

       // validate start position.
       dtoken = strsep(&ctoken, "-");
       if (isdigit(*dtoken)) {
         if (getval(dtoken, min, (min ? max : max-1)) < 0) return 1;
       } else if (getindex(dtoken, max) < 0) return 1;

       // validate end position.
       if (!ctoken) {
         if (skip) return 1; // case 10/20 or 1,2,4/3
       }
       else if (*ctoken) {// e.g. N-M
         if (isdigit(*ctoken)) {
           if (getval(ctoken, min, (min ? max : max-1)) < 0) return 1;
         } else if (getindex(ctoken, max) < 0) return 1;
       } else return 1; // error condition 'N-'
     }
   }
   return 0;
 }

 static int parse_crontab(char *fname)
 {
   char *line;
   int lno, fd = xopen(fname, O_RDONLY);
   long plen = 0;

   for (lno = 1; (line = get_rawline(fd, &plen, '\n')); lno++,free(line)) {
     char *name, *val, *tokens[5] = {0,}, *ptr = line;
     int count = 0;

     if (line[plen - 1] == '\n') line[--plen] = '\0';
     else {
       snprintf(toybuf, sizeof(toybuf), "'%d': premature EOF\n", lno);
       goto OUT;
     }

     ptr = omitspace(ptr);
     if (!*ptr || *ptr == '#' || *ptr == '@') continue;
     while (count<5) {
       int len = strcspn(ptr, " \t");

       if (ptr[len]) ptr[len++] = '\0';
       tokens[count++] = ptr;
       ptr += len;
       ptr = omitspace(ptr);
       if (!*ptr) break;
     }
     switch (count) {
       case 1: // form SHELL=/bin/sh
         name = tokens[0];
         if ((val = strchr(name, '='))) *val++ = 0;
         if (!val || !*val) {
           snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
           goto OUT;
         }
         break;
       case 2: // form SHELL =/bin/sh or SHELL= /bin/sh
         name = tokens[0];
         if ((val = strchr(name, '='))) {
           *val = 0;
           val = tokens[1];
         } else {
           if (*(tokens[1]) != '=') {
             snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
             goto OUT;
           }
           val = tokens[1] + 1;
         }
         if (!*val) {
           snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
           goto OUT;
         }
         break;
       case 3: // NAME = VAL
         name = tokens[0];
         val = tokens[2];
         if (*(tokens[1]) != '=') {
           snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
           goto OUT;
         }
         break;
       default:
         if (validate_component(0, 60, tokens[0])) {
           snprintf(toybuf, sizeof(toybuf), "'%d': bad minute\n", lno);
           goto OUT;
         }
         if (validate_component(0, 24, tokens[1])) {
           snprintf(toybuf, sizeof(toybuf), "'%d': bad hour\n", lno);
           goto OUT;
         }
         if (validate_component(1, 31, tokens[2])) {
           snprintf(toybuf, sizeof(toybuf), "'%d': bad day-of-month\n", lno);
           goto OUT;
         }
         if (validate_component(1, 12, tokens[3])) {
           snprintf(toybuf, sizeof(toybuf), "'%d': bad month\n", lno);
           goto OUT;
         }
         if (validate_component(0, 7, tokens[4])) {
           snprintf(toybuf, sizeof(toybuf), "'%d': bad day-of-week\n", lno);
           goto OUT;
         }
         if (!*ptr) { // don't have any cmd to execute.
           snprintf(toybuf, sizeof(toybuf), "'%d': bad command\n", lno);
           goto OUT;
         }
         break;
     }
   }
   xclose(fd);
   return 0;
 OUT:
   free(line);
   printf("Error at line no %s", toybuf);
   xclose(fd);
   return 1;
 }

 static void do_list(char *name)
 {
   int fdin;

   snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, name);
   if ((fdin = open(toybuf, O_RDONLY)) == -1)
     error_exit("No crontab for '%s'", name);
   xsendfile(fdin, 1);
   xclose(fdin);
 }

 static void do_remove(char *name)
 {
   snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, name);
   if (unlink(toybuf))
     error_exit("No crontab for '%s'", name);
 }

 static void update_crontab(char *src, char *dest)
 {
   int fdin, fdout;

   snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, dest);
   fdout = xcreate(toybuf, O_WRONLY|O_CREAT|O_TRUNC, 0600);
   fdin = xopen(src, O_RDONLY);
   xsendfile(fdin, fdout);
   xclose(fdin);

   fchown(fdout, getuid(), geteuid());
   xclose(fdout);
 }

 static void do_replace(char *name)
 {
   char *fname = *toys.optargs ? *toys.optargs : "-";
   char tname[] = "/tmp/crontab.XXXXXX";

   if ((*fname == '-') && !*(fname+1)) {
     int tfd = mkstemp(tname);

     if (tfd < 0) perror_exit("mkstemp");
     xsendfile(0, tfd);
     xclose(tfd);
     fname = tname;
   }

   if (parse_crontab(fname))
     error_exit("errors in crontab file '%s', can't install.", fname);
   update_crontab(fname, name);
   unlink(tname);
 }

 static void do_edit(struct passwd *pwd)
 {
   struct stat sb;
   time_t mtime = 0;
   int srcfd, destfd, status;
   pid_t pid, cpid;
   char tname[] = "/tmp/crontab.XXXXXX";

   if ((destfd = mkstemp(tname)) < 0)
     perror_exit("Can't open tmp file");

   fchmod(destfd, 0666);
   snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, pwd->pw_name);

   if (!stat(toybuf, &sb)) { // file exists and have some content.
     if (sb.st_size) {
       srcfd = xopen(toybuf, O_RDONLY);
       xsendfile(srcfd, destfd);
       xclose(srcfd);
     }
   } else printf("No crontab for '%s'- using an empty one\n", pwd->pw_name);
   xclose(destfd);

   if (!stat(tname, &sb)) mtime = sb.st_mtime;

 RETRY:
   if (!(pid = xfork())) {
     char *prog = pwd->pw_shell;

     xsetuser(pwd);
     if (pwd->pw_uid) {
       if (setenv("USER", pwd->pw_name, 1)) _exit(1);
       if (setenv("LOGNAME", pwd->pw_name, 1)) _exit(1);
     }
     if (setenv("HOME", pwd->pw_dir, 1)) _exit(1);
     if (setenv("SHELL",((!prog || !*prog) ? "/bin/sh" : prog), 1)) _exit(1);

     if (!(prog = getenv("VISUAL"))) {
       if (!(prog = getenv("EDITOR")))
         prog = "vi";
     }
     execlp(prog, prog, tname, (char *) NULL);
     perror_exit("can't execute '%s'", prog);
   }

   // Parent Process.
   do {
     cpid = waitpid(pid, &status, 0);
   } while ((cpid == -1) && (errno == EINTR));

   if (!stat(tname, &sb) && (mtime == sb.st_mtime)) {
     printf("%s: no changes made to crontab\n", toys.which->name);
     unlink(tname);
     return;
   }
   printf("%s: installing new crontab\n", toys.which->name);
   if (parse_crontab(tname)) {
     snprintf(toybuf, sizeof(toybuf), "errors in crontab file, can't install.\n"
         "Do you want to retry the same edit? ");
     if (!yesno(toybuf, 0)) {
       error_msg("edits left in '%s'", tname);
       return;
     }
     goto RETRY;
   }
   // parsing of crontab success; update the crontab.
   update_crontab(tname, pwd->pw_name);
   unlink(tname);
 }

 void crontab_main(void)
 {
   struct passwd *pwd = NULL;
   long FLAG_elr = toys.optflags & (FLAG_e|FLAG_l|FLAG_r);

   if (TT.cdir && (TT.cdir[strlen(TT.cdir)-1] != '/'))
     TT.cdir = xmprintf("%s/", TT.cdir);
   if (!TT.cdir) TT.cdir = xstrdup("/var/spool/cron/crontabs/");

   if (toys.optflags & FLAG_u) {
     if (getuid()) error_exit("must be privileged to use -u");
     pwd = xgetpwnam(TT.user);
   } else pwd = xgetpwuid(getuid());

   if (!toys.optc) {
     if (!FLAG_elr) {
       if (toys.optflags & FLAG_u) {
         toys.exithelp++;
         error_exit("file name must be specified for replace");
       }
       do_replace(pwd->pw_name);
     }
     else if (toys.optflags & FLAG_e) do_edit(pwd);
     else if (toys.optflags & FLAG_l) do_list(pwd->pw_name);
     else if (toys.optflags & FLAG_r) do_remove(pwd->pw_name);
   } else {
     if (FLAG_elr) {
       toys.exithelp++;
       error_exit("no arguments permitted after this option");
     }
     do_replace(pwd->pw_name);
   }
   if (!(toys.optflags & FLAG_c)) free(TT.cdir);
 }
	/* crontab.c - files used to schedule the execution of programs.
	*
	* Copyright 2014 Ranjan Kumar <ranjankumar.bth@gmail.com>
	*
	* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/crontab.html

	USE_CRONTAB(NEWTOY(crontab, "c:u:elr[!elr]", TOYFLAG_USR\|TOYFLAG_BIN\|TOYFLAG_STAYROOT))

	config CRONTAB
	bool "crontab"
	default n
	help
	usage: crontab [-u user] FILE
	[-u user] [-e \| -l \| -r]
	[-c dir]

	Files used to schedule the execution of programs.

	-c crontab dir
	-e edit user's crontab
	-l list user's crontab
	-r delete user's crontab
	-u user
	FILE Replace crontab by FILE ('-': stdin)
	*/
	#define FOR_crontab
	#include "toys.h"

	GLOBALS(
	char *user;
	char *cdir;
	)

	static char omitspace(char line)
	{
	while (line == ' ' \|\| line == '\t') line++;
	return line;
	}

	/*
	* Names can also be used for the 'month' and 'day of week' fields
	* (First three letters of the particular day or month).
	*/
	static int getindex(char *src, int size)
	{
	int i;
	char days[]={"sun""mon""tue""wed""thu""fri""sat"};
	char months[]={"jan""feb""mar""apr""may""jun""jul"
	"aug""sep""oct""nov""dec"};
	char *field = (size == 12) ? months : days;

	// strings are not allowed for min, hour and dom fields.
	if (!(size == 7 \|\| size == 12)) return -1;

	for (i = 0; field[i]; i += 3) {
	if (!strncasecmp(src, &field[i], 3))
	return (i/3);
	}
	return -1;
	}

	static long getval(char *num, long low, long high)
	{
	long val = strtol(num, &num, 10);

	if (*num \|\| (val < low) \|\| (val > high)) return -1;
	return val;
	}

	// Validate minute, hour, day of month, month and day of week fields.
	static int validate_component(int min, int max, char *src)
	{
	int skip = 0;
	char *ptr;

	if (!src) return 1;
	if ((ptr = strchr(src, '/'))) {
	*ptr++ = 0;
	if ((skip = getval(ptr, min, (min ? max: max-1))) < 0) return 1;
	}

	if (src == '-' \|\| src == ',') return 1;
	if (src == '') {
	if (*(src+1)) return 1;
	}
	else {
	for (;;) {
	char ctoken = strsep(&src, ","), dtoken;

	if (!ctoken) break;
	if (!*ctoken) return 1;

	// validate start position.
	dtoken = strsep(&ctoken, "-");
	if (isdigit(*dtoken)) {
	if (getval(dtoken, min, (min ? max : max-1)) < 0) return 1;
	} else if (getindex(dtoken, max) < 0) return 1;

	// validate end position.
	if (!ctoken) {
	if (skip) return 1; // case 10/20 or 1,2,4/3
	}
	else if (*ctoken) {// e.g. N-M
	if (isdigit(*ctoken)) {
	if (getval(ctoken, min, (min ? max : max-1)) < 0) return 1;
	} else if (getindex(ctoken, max) < 0) return 1;
	} else return 1; // error condition 'N-'
	}
	}
	return 0;
	}

	static int parse_crontab(char *fname)
	{
	char *line;
	int lno, fd = xopen(fname, O_RDONLY);
	long plen = 0;

	for (lno = 1; (line = get_rawline(fd, &plen, '\n')); lno++,free(line)) {
	char name, val, tokens[5] = {0,}, ptr = line;
	int count = 0;

	if (line[plen - 1] == '\n') line[--plen] = '\0';
	else {
	snprintf(toybuf, sizeof(toybuf), "'%d': premature EOF\n", lno);
	goto OUT;
	}

	ptr = omitspace(ptr);
	if (!ptr \|\| ptr == '#' \|\| *ptr == '@') continue;
	while (count<5) {
	int len = strcspn(ptr, " \t");

	if (ptr[len]) ptr[len++] = '\0';
	tokens[count++] = ptr;
	ptr += len;
	ptr = omitspace(ptr);
	if (!*ptr) break;
	}
	switch (count) {
	case 1: // form SHELL=/bin/sh
	name = tokens[0];
	if ((val = strchr(name, '='))) *val++ = 0;
	if (!val \|\| !*val) {
	snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
	goto OUT;
	}
	break;
	case 2: // form SHELL =/bin/sh or SHELL= /bin/sh
	name = tokens[0];
	if ((val = strchr(name, '='))) {
	*val = 0;
	val = tokens[1];
	} else {
	if (*(tokens[1]) != '=') {
	snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
	goto OUT;
	}
	val = tokens[1] + 1;
	}
	if (!*val) {
	snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
	goto OUT;
	}
	break;
	case 3: // NAME = VAL
	name = tokens[0];
	val = tokens[2];
	if (*(tokens[1]) != '=') {
	snprintf(toybuf, sizeof(toybuf), "'%d': %s\n", lno, line);
	goto OUT;
	}
	break;
	default:
	if (validate_component(0, 60, tokens[0])) {
	snprintf(toybuf, sizeof(toybuf), "'%d': bad minute\n", lno);
	goto OUT;
	}
	if (validate_component(0, 24, tokens[1])) {
	snprintf(toybuf, sizeof(toybuf), "'%d': bad hour\n", lno);
	goto OUT;
	}
	if (validate_component(1, 31, tokens[2])) {
	snprintf(toybuf, sizeof(toybuf), "'%d': bad day-of-month\n", lno);
	goto OUT;
	}
	if (validate_component(1, 12, tokens[3])) {
	snprintf(toybuf, sizeof(toybuf), "'%d': bad month\n", lno);
	goto OUT;
	}
	if (validate_component(0, 7, tokens[4])) {
	snprintf(toybuf, sizeof(toybuf), "'%d': bad day-of-week\n", lno);
	goto OUT;
	}
	if (!*ptr) { // don't have any cmd to execute.
	snprintf(toybuf, sizeof(toybuf), "'%d': bad command\n", lno);
	goto OUT;
	}
	break;
	}
	}
	xclose(fd);
	return 0;
	OUT:
	free(line);
	printf("Error at line no %s", toybuf);
	xclose(fd);
	return 1;
	}

	static void do_list(char *name)
	{
	int fdin;

	snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, name);
	if ((fdin = open(toybuf, O_RDONLY)) == -1)
	error_exit("No crontab for '%s'", name);
	xsendfile(fdin, 1);
	xclose(fdin);
	}

	static void do_remove(char *name)
	{
	snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, name);
	if (unlink(toybuf))
	error_exit("No crontab for '%s'", name);
	}

	static void update_crontab(char src, char dest)
	{
	int fdin, fdout;

	snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, dest);
	fdout = xcreate(toybuf, O_WRONLY\|O_CREAT\|O_TRUNC, 0600);
	fdin = xopen(src, O_RDONLY);
	xsendfile(fdin, fdout);
	xclose(fdin);

	fchown(fdout, getuid(), geteuid());
	xclose(fdout);
	}

	static void do_replace(char *name)
	{
	char fname = toys.optargs ? *toys.optargs : "-";
	char tname[] = "/tmp/crontab.XXXXXX";

	if ((fname == '-') && !(fname+1)) {
	int tfd = mkstemp(tname);

	if (tfd < 0) perror_exit("mkstemp");
	xsendfile(0, tfd);
	xclose(tfd);
	fname = tname;
	}

	if (parse_crontab(fname))
	error_exit("errors in crontab file '%s', can't install.", fname);
	update_crontab(fname, name);
	unlink(tname);
	}

	static void do_edit(struct passwd *pwd)
	{
	struct stat sb;
	time_t mtime = 0;
	int srcfd, destfd, status;
	pid_t pid, cpid;
	char tname[] = "/tmp/crontab.XXXXXX";

	if ((destfd = mkstemp(tname)) < 0)
	perror_exit("Can't open tmp file");

	fchmod(destfd, 0666);
	snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, pwd->pw_name);

	if (!stat(toybuf, &sb)) { // file exists and have some content.
	if (sb.st_size) {
	srcfd = xopen(toybuf, O_RDONLY);
	xsendfile(srcfd, destfd);
	xclose(srcfd);
	}
	} else printf("No crontab for '%s'- using an empty one\n", pwd->pw_name);
	xclose(destfd);

	if (!stat(tname, &sb)) mtime = sb.st_mtime;

	RETRY:
	if (!(pid = xfork())) {
	char *prog = pwd->pw_shell;

	xsetuser(pwd);
	if (pwd->pw_uid) {
	if (setenv("USER", pwd->pw_name, 1)) _exit(1);
	if (setenv("LOGNAME", pwd->pw_name, 1)) _exit(1);
	}
	if (setenv("HOME", pwd->pw_dir, 1)) _exit(1);
	if (setenv("SHELL",((!prog \|\| !*prog) ? "/bin/sh" : prog), 1)) _exit(1);

	if (!(prog = getenv("VISUAL"))) {
	if (!(prog = getenv("EDITOR")))
	prog = "vi";
	}
	execlp(prog, prog, tname, (char *) NULL);
	perror_exit("can't execute '%s'", prog);
	}

	// Parent Process.
	do {
	cpid = waitpid(pid, &status, 0);
	} while ((cpid == -1) && (errno == EINTR));

	if (!stat(tname, &sb) && (mtime == sb.st_mtime)) {
	printf("%s: no changes made to crontab\n", toys.which->name);
	unlink(tname);
	return;
	}
	printf("%s: installing new crontab\n", toys.which->name);
	if (parse_crontab(tname)) {
	snprintf(toybuf, sizeof(toybuf), "errors in crontab file, can't install.\n"
	"Do you want to retry the same edit? ");
	if (!yesno(toybuf, 0)) {
	error_msg("edits left in '%s'", tname);
	return;
	}
	goto RETRY;
	}
	// parsing of crontab success; update the crontab.
	update_crontab(tname, pwd->pw_name);
	unlink(tname);
	}

	void crontab_main(void)
	{
	struct passwd *pwd = NULL;
	long FLAG_elr = toys.optflags & (FLAG_e\|FLAG_l\|FLAG_r);

	if (TT.cdir && (TT.cdir[strlen(TT.cdir)-1] != '/'))
	TT.cdir = xmprintf("%s/", TT.cdir);
	if (!TT.cdir) TT.cdir = xstrdup("/var/spool/cron/crontabs/");

	if (toys.optflags & FLAG_u) {
	if (getuid()) error_exit("must be privileged to use -u");
	pwd = xgetpwnam(TT.user);
	} else pwd = xgetpwuid(getuid());

	if (!toys.optc) {
	if (!FLAG_elr) {
	if (toys.optflags & FLAG_u) {
	toys.exithelp++;
	error_exit("file name must be specified for replace");
	}
	do_replace(pwd->pw_name);
	}
	else if (toys.optflags & FLAG_e) do_edit(pwd);
	else if (toys.optflags & FLAG_l) do_list(pwd->pw_name);
	else if (toys.optflags & FLAG_r) do_remove(pwd->pw_name);
	} else {
	if (FLAG_elr) {
	toys.exithelp++;
	error_exit("no arguments permitted after this option");
	}
	do_replace(pwd->pw_name);
	}
	if (!(toys.optflags & FLAG_c)) free(TT.cdir);
	}