From 7a976a09cc2327dcf0baf8708d3420136dfbc3fc Mon Sep 17 00:00:00 2001 From: Ashwini Sharma Date: Thu, 30 Oct 2014 18:36:09 -0500 Subject: Attached are new toys TR and CRONTAB. *tr.c*: It translate, squezze and delete characters. Supported classes are alpha, alnum, digit, lower, upper space, blank, puct, cntrl and xdigit. *crontab.c*: Companion of crond. It maintains crontab files. --- toys/pending/crontab.c | 366 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 366 insertions(+) create mode 100644 toys/pending/crontab.c (limited to 'toys/pending/crontab.c') diff --git a/toys/pending/crontab.c b/toys/pending/crontab.c new file mode 100644 index 00000000..35f6d659 --- /dev/null +++ b/toys/pending/crontab.c @@ -0,0 +1,366 @@ +/* crontab.c - files used to schedule the execution of programs. + * + * Copyright 2014 Ranjan Kumar + * + * 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); +} -- cgit v1.2.3