Путь: Toys/Pending, команды версии: Ver.4 Ver.9 crontab Комментарии в файле crontab.c :
Исходный текст в файле crontab.c #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)
{
FILE *fp = xfopen(fname, "r");
long len = 0;
char *line = NULL;
size_t allocated_length;
int lno;
for (lno = 1; (len = getline(&line, &allocated_length, fp)) > 0; lno++) {
char *name, *val, *tokens[5] = {0,}, *ptr = line;
int count = 0;
if (line[len - 1] == '\n') line[--len] = '\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;
}
}
free(line);
fclose(fp);
return 0;
OUT:
free(line);
printf("Error at line no %s", toybuf);
fclose(fp);
return 1;
}
static void do_list(char *name)
{
int fdin;
snprintf(toybuf, sizeof(toybuf), "%s%s", TT.cdir, name);
fdin = xopenro(toybuf);
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 = xopenro(src);
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 = xopenro(toybuf);
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)) {
fprintf(stderr, "errors in crontab file, can't install.\n"
"Do you want to retry the same edit? ");
if (!yesno(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)
help_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) help_exit("no arguments permitted after this option");
do_replace(pwd->pw_name);
}
if (!(toys.optflags & FLAG_c)) free(TT.cdir);
} |
 |