mirror of
https://github.com/sheumann/hush.git
synced 2024-07-15 15:29:07 +00:00
crontab: almost complete rewrite
crontab: make options consistent with other implementations text data bss dec hex filename 2042 4 0 2046 7fe busybox.t1/miscutils/crontab.o 1331 0 0 1331 533 busybox.t2/miscutils/crontab.o function old new delta edit_file 733 956 +223 open_as_user - 171 +171 packed_usage 23652 23650 -2 CDir 8 4 -4 ChangeUser 139 - -139 crontab_main 1522 616 -906 ------------------------------------------------------------------------------ (add/remove: 1/1 grow/shrink: 1/3 up/down: 394/-1051) Total: -657 bytes
This commit is contained in:
Denis Vlasenko
parent
cd5c61cd3b
commit
069e347863
@ -510,15 +510,14 @@ USE_FEATURE_BRCTL_FANCY("\n" \
|
||||
" -c dir Working dir"
|
||||
|
||||
#define crontab_trivial_usage \
|
||||
"[-c dir] {file|-}|[-u|-l|-e|-d user]"
|
||||
"[-c DIR] [-u USER] [-ler]|[FILE]"
|
||||
#define crontab_full_usage \
|
||||
" file [opts] Replace crontab from file\n" \
|
||||
" - [opts] Replace crontab from stdin\n" \
|
||||
" -u user User\n" \
|
||||
" -l [user] List crontab for user\n" \
|
||||
" -e [user] Edit crontab for user\n" \
|
||||
" -d [user] Delete crontab for user\n" \
|
||||
" -c dir Crontab directory"
|
||||
" -c Crontab directory" \
|
||||
"\n -u User" \
|
||||
"\n -l List crontab" \
|
||||
"\n -e Edit crontab" \
|
||||
"\n -r Delete crontab" \
|
||||
"\n FILE Replace crontab by FILE ('-': stdin)" \
|
||||
|
||||
#define cryptpw_trivial_usage \
|
||||
"[-a des|md5] [string]"
|
||||
|
||||
@ -25,321 +25,225 @@
|
||||
#define PATH_VI "/bin/vi" /* location of vi */
|
||||
#endif
|
||||
|
||||
static const char *CDir = CRONTABS;
|
||||
|
||||
static void EditFile(const char *user, const char *file);
|
||||
static int GetReplaceStream(const char *user, const char *file);
|
||||
static int ChangeUser(const char *user, short dochdir);
|
||||
|
||||
int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
||||
int crontab_main(int ac, char **av)
|
||||
static void change_user(const struct passwd *pas)
|
||||
{
|
||||
enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE;
|
||||
const struct passwd *pas;
|
||||
const char *repFile = NULL;
|
||||
int repFd = 0;
|
||||
int i;
|
||||
char caller[256]; /* user that ran program */
|
||||
char buf[1024];
|
||||
int UserId;
|
||||
|
||||
UserId = getuid();
|
||||
pas = getpwuid(UserId);
|
||||
if (pas == NULL)
|
||||
bb_perror_msg_and_die("getpwuid");
|
||||
|
||||
safe_strncpy(caller, pas->pw_name, sizeof(caller));
|
||||
|
||||
i = 1;
|
||||
if (ac > 1) {
|
||||
if (LONE_DASH(av[1])) {
|
||||
option = REPLACE;
|
||||
++i;
|
||||
} else if (av[1][0] != '-') {
|
||||
option = REPLACE;
|
||||
++i;
|
||||
repFile = av[1];
|
||||
}
|
||||
}
|
||||
|
||||
for (; i < ac; ++i) {
|
||||
char *ptr = av[i];
|
||||
|
||||
if (*ptr != '-')
|
||||
break;
|
||||
ptr += 2;
|
||||
|
||||
switch (ptr[-1]) {
|
||||
case 'l':
|
||||
if (ptr[-1] == 'l')
|
||||
option = LIST;
|
||||
/* fall through */
|
||||
case 'e':
|
||||
if (ptr[-1] == 'e')
|
||||
option = EDIT;
|
||||
/* fall through */
|
||||
case 'd':
|
||||
if (ptr[-1] == 'd')
|
||||
option = DELETE;
|
||||
/* fall through */
|
||||
case 'u':
|
||||
if (i + 1 < ac && av[i+1][0] != '-') {
|
||||
++i;
|
||||
if (getuid() == geteuid()) {
|
||||
pas = getpwnam(av[i]);
|
||||
if (pas) {
|
||||
UserId = pas->pw_uid;
|
||||
} else {
|
||||
bb_error_msg_and_die("user %s unknown", av[i]);
|
||||
}
|
||||
} else {
|
||||
bb_error_msg_and_die("only the superuser may specify a user");
|
||||
}
|
||||
}
|
||||
break;
|
||||
case 'c':
|
||||
if (getuid() == geteuid()) {
|
||||
CDir = (*ptr) ? ptr : av[++i];
|
||||
} else {
|
||||
bb_error_msg_and_die("-c option: superuser only");
|
||||
}
|
||||
break;
|
||||
default:
|
||||
i = ac;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (i != ac || option == NONE)
|
||||
bb_show_usage();
|
||||
|
||||
/*
|
||||
* Get password entry
|
||||
*/
|
||||
|
||||
pas = getpwuid(UserId);
|
||||
if (pas == NULL)
|
||||
bb_perror_msg_and_die("getpwuid");
|
||||
|
||||
/*
|
||||
* If there is a replacement file, obtain a secure descriptor to it.
|
||||
*/
|
||||
|
||||
if (repFile) {
|
||||
repFd = GetReplaceStream(caller, repFile);
|
||||
if (repFd < 0)
|
||||
bb_error_msg_and_die("cannot read replacement file");
|
||||
}
|
||||
|
||||
/*
|
||||
* Change directory to our crontab directory
|
||||
*/
|
||||
|
||||
xchdir(CDir);
|
||||
|
||||
/*
|
||||
* Handle options as appropriate
|
||||
*/
|
||||
|
||||
switch (option) {
|
||||
case LIST:
|
||||
{
|
||||
FILE *fi;
|
||||
|
||||
fi = fopen(pas->pw_name, "r");
|
||||
if (fi) {
|
||||
while (fgets(buf, sizeof(buf), fi) != NULL)
|
||||
fputs(buf, stdout);
|
||||
fclose(fi);
|
||||
} else {
|
||||
bb_error_msg("no crontab for %s", pas->pw_name);
|
||||
}
|
||||
}
|
||||
break;
|
||||
case EDIT:
|
||||
{
|
||||
/* FIXME: messy code here! we have file copying helpers for this! */
|
||||
FILE *fi;
|
||||
int fd;
|
||||
int n;
|
||||
char tmp[128];
|
||||
|
||||
snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid());
|
||||
fd = xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
|
||||
/* race, use fchown */
|
||||
chown(tmp, getuid(), getgid());
|
||||
fi = fopen(pas->pw_name, "r");
|
||||
if (fi) {
|
||||
while ((n = fread(buf, 1, sizeof(buf), fi)) > 0)
|
||||
full_write(fd, buf, n);
|
||||
}
|
||||
EditFile(caller, tmp);
|
||||
remove(tmp);
|
||||
lseek(fd, 0L, SEEK_SET);
|
||||
repFd = fd;
|
||||
}
|
||||
option = REPLACE;
|
||||
/* fall through */
|
||||
case REPLACE:
|
||||
{
|
||||
/* same here */
|
||||
char path[1024];
|
||||
int fd;
|
||||
int n;
|
||||
|
||||
snprintf(path, sizeof(path), "%s.new", pas->pw_name);
|
||||
fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600);
|
||||
if (fd >= 0) {
|
||||
while ((n = read(repFd, buf, sizeof(buf))) > 0) {
|
||||
full_write(fd, buf, n);
|
||||
}
|
||||
close(fd);
|
||||
rename(path, pas->pw_name);
|
||||
} else {
|
||||
bb_error_msg("cannot create %s/%s", CDir, path);
|
||||
}
|
||||
close(repFd);
|
||||
}
|
||||
break;
|
||||
case DELETE:
|
||||
remove(pas->pw_name);
|
||||
break;
|
||||
case NONE:
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
/*
|
||||
* Bump notification file. Handle window where crond picks file up
|
||||
* before we can write our entry out.
|
||||
*/
|
||||
|
||||
if (option == REPLACE || option == DELETE) {
|
||||
FILE *fo;
|
||||
struct stat st;
|
||||
|
||||
while ((fo = fopen(CRONUPDATE, "a"))) {
|
||||
fprintf(fo, "%s\n", pas->pw_name);
|
||||
fflush(fo);
|
||||
if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) {
|
||||
fclose(fo);
|
||||
break;
|
||||
}
|
||||
fclose(fo);
|
||||
/* loop */
|
||||
}
|
||||
if (fo == NULL) {
|
||||
bb_error_msg("cannot append to %s/%s", CDir, CRONUPDATE);
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int GetReplaceStream(const char *user, const char *file)
|
||||
{
|
||||
int filedes[2];
|
||||
int pid;
|
||||
int fd;
|
||||
int n;
|
||||
char buf[1024];
|
||||
|
||||
if (pipe(filedes) < 0) {
|
||||
perror("pipe");
|
||||
return -1;
|
||||
}
|
||||
pid = fork();
|
||||
if (pid < 0) {
|
||||
perror("fork");
|
||||
return -1;
|
||||
}
|
||||
if (pid > 0) {
|
||||
/*
|
||||
* PARENT
|
||||
*/
|
||||
|
||||
close(filedes[1]);
|
||||
if (read(filedes[0], buf, 1) != 1) {
|
||||
close(filedes[0]);
|
||||
filedes[0] = -1;
|
||||
}
|
||||
return filedes[0];
|
||||
}
|
||||
|
||||
/*
|
||||
* CHILD
|
||||
*/
|
||||
|
||||
close(filedes[0]);
|
||||
|
||||
if (ChangeUser(user, 0) < 0)
|
||||
exit(0);
|
||||
|
||||
xfunc_error_retval = 0;
|
||||
fd = xopen(file, O_RDONLY);
|
||||
buf[0] = 0;
|
||||
write(filedes[1], buf, 1);
|
||||
while ((n = read(fd, buf, sizeof(buf))) > 0) {
|
||||
write(filedes[1], buf, n);
|
||||
}
|
||||
exit(0);
|
||||
}
|
||||
|
||||
static void EditFile(const char *user, const char *file)
|
||||
{
|
||||
int pid = fork();
|
||||
|
||||
if (pid == 0) {
|
||||
/*
|
||||
* CHILD - change user and run editor
|
||||
*/
|
||||
const char *ptr;
|
||||
|
||||
if (ChangeUser(user, 1) < 0)
|
||||
exit(0);
|
||||
ptr = getenv("VISUAL");
|
||||
if (ptr == NULL)
|
||||
ptr = getenv("EDITOR");
|
||||
if (ptr == NULL)
|
||||
ptr = PATH_VI;
|
||||
|
||||
ptr = xasprintf("%s %s", ptr, file);
|
||||
execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", ptr, NULL);
|
||||
bb_perror_msg_and_die("exec");
|
||||
}
|
||||
if (pid < 0) {
|
||||
/*
|
||||
* PARENT - failure
|
||||
*/
|
||||
bb_perror_msg_and_die("fork");
|
||||
}
|
||||
wait4(pid, NULL, 0, NULL);
|
||||
}
|
||||
|
||||
static int ChangeUser(const char *user, short dochdir)
|
||||
{
|
||||
struct passwd *pas;
|
||||
|
||||
/*
|
||||
* Obtain password entry and change privileges
|
||||
*/
|
||||
|
||||
pas = getpwnam(user);
|
||||
if (pas == NULL) {
|
||||
bb_perror_msg_and_die("cannot get uid for %s", user);
|
||||
}
|
||||
setenv("USER", pas->pw_name, 1);
|
||||
setenv("HOME", pas->pw_dir, 1);
|
||||
setenv("SHELL", DEFAULT_SHELL, 1);
|
||||
|
||||
/*
|
||||
* Change running state to the user in question
|
||||
*/
|
||||
/* initgroups, setgid, setuid */
|
||||
change_identity(pas);
|
||||
|
||||
if (dochdir) {
|
||||
if (chdir(pas->pw_dir) < 0) {
|
||||
bb_perror_msg("chdir(%s) by %s failed", pas->pw_dir, user);
|
||||
xchdir(TMPDIR);
|
||||
if (chdir(pas->pw_dir) < 0) {
|
||||
bb_perror_msg("chdir(%s) by %s failed",
|
||||
pas->pw_dir, pas->pw_name);
|
||||
xchdir(TMPDIR);
|
||||
}
|
||||
}
|
||||
|
||||
static void edit_file(const struct passwd *pas, const char *file)
|
||||
{
|
||||
const char *ptr;
|
||||
int pid = vfork();
|
||||
|
||||
if (pid < 0) /* failure */
|
||||
bb_perror_msg_and_die("vfork");
|
||||
if (pid) { /* parent */
|
||||
wait4pid(pid);
|
||||
return;
|
||||
}
|
||||
|
||||
/* CHILD - change user and run editor */
|
||||
change_user(pas);
|
||||
ptr = getenv("VISUAL");
|
||||
if (!ptr) {
|
||||
ptr = getenv("EDITOR");
|
||||
if (!ptr)
|
||||
ptr = PATH_VI;
|
||||
}
|
||||
|
||||
/* TODO: clean up the environment!!! */
|
||||
/* not execlp - we won't use PATH */
|
||||
execl(ptr, ptr, file, NULL);
|
||||
bb_perror_msg_and_die("exec %s", ptr);
|
||||
}
|
||||
|
||||
static int open_as_user(const struct passwd *pas, const char *file)
|
||||
{
|
||||
int filedes[2];
|
||||
pid_t pid;
|
||||
char c;
|
||||
|
||||
xpipe(filedes);
|
||||
pid = vfork();
|
||||
if (pid < 0) /* ERROR */
|
||||
bb_perror_msg_and_die("vfork");
|
||||
if (pid) { /* PARENT */
|
||||
int n = safe_read(filedes[0], &c, 1);
|
||||
close(filedes[0]);
|
||||
close(filedes[1]);
|
||||
if (n > 0) /* child says it can read */
|
||||
return open(file, O_RDONLY);
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* CHILD */
|
||||
|
||||
/* initgroups, setgid, setuid */
|
||||
change_identity(pas);
|
||||
|
||||
/* We just try to read one byte. If that works, file is readable
|
||||
* under this user. We signal that by sending one byte to parent. */
|
||||
if (safe_read(xopen(file, O_RDONLY), &c, 1) == 1)
|
||||
safe_write(filedes[1], &c, 1); /* "papa, I can read!" */
|
||||
_exit(0);
|
||||
}
|
||||
|
||||
int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
||||
int crontab_main(int argc, char **argv)
|
||||
{
|
||||
const struct passwd *pas;
|
||||
const char *crontab_dir = CRONTABS;
|
||||
char *tmp_fname;
|
||||
char *new_fname;
|
||||
char *user_name; /* -u USER */
|
||||
int fd;
|
||||
int opt_ler;
|
||||
uid_t my_uid;
|
||||
|
||||
/* file [opts] Replace crontab from file
|
||||
* - [opts] Replace crontab from stdin
|
||||
* -u user User
|
||||
* -c dir Crontab directory
|
||||
* -l List crontab for user
|
||||
* -e Edit crontab for user
|
||||
* -r Delete crontab for user
|
||||
* bbox also supports -d == -r, but most other crontab
|
||||
* implementations do not. Deprecated.
|
||||
*/
|
||||
enum {
|
||||
OPT_u = (1 << 0),
|
||||
OPT_c = (1 << 1),
|
||||
OPT_l = (1 << 2),
|
||||
OPT_e = (1 << 3),
|
||||
OPT_r = (1 << 4),
|
||||
OPT_ler = OPT_l + OPT_e + OPT_r,
|
||||
};
|
||||
|
||||
my_uid = getuid();
|
||||
|
||||
opt_complementary = "?1:dr"; /* max one argument; -d implies -r */
|
||||
opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir);
|
||||
argv += optind;
|
||||
|
||||
if (opt_ler & (OPT_u|OPT_c))
|
||||
if (my_uid != geteuid())
|
||||
bb_error_msg_and_die("only root can use -c or -u");
|
||||
|
||||
if (opt_ler & OPT_u) {
|
||||
pas = getpwnam(user_name);
|
||||
if (!pas)
|
||||
bb_error_msg_and_die("user %s is not known", user_name);
|
||||
my_uid = pas->pw_uid;
|
||||
} else {
|
||||
pas = getpwuid(my_uid);
|
||||
if (!pas)
|
||||
bb_perror_msg_and_die("no user record for UID %u",
|
||||
(unsigned)my_uid);
|
||||
}
|
||||
|
||||
#define user_name DONT_USE_ME_BEYOND_THIS_POINT
|
||||
#define my_uid DONT_USE_ME_BEYOND_THIS_POINT
|
||||
|
||||
/* From now on, keep only -l, -e, -r bits */
|
||||
opt_ler &= OPT_ler;
|
||||
if ((opt_ler - 1) & opt_ler) /* more than one bit set? */
|
||||
bb_show_usage();
|
||||
|
||||
/* Read replacement file under user's UID/GID/group vector */
|
||||
if (!opt_ler) { /* Replace? */
|
||||
if (!argv[0])
|
||||
bb_show_usage();
|
||||
if (NOT_LONE_DASH(argv[0])) {
|
||||
fd = open_as_user(pas, argv[0]);
|
||||
if (fd < 0)
|
||||
bb_error_msg_and_die("user %s cannot read %s",
|
||||
pas->pw_name, argv[0]);
|
||||
xmove_fd(fd, STDIN_FILENO);
|
||||
}
|
||||
}
|
||||
return pas->pw_uid;
|
||||
|
||||
/* cd to our crontab directory */
|
||||
xchdir(crontab_dir);
|
||||
|
||||
tmp_fname = NULL;
|
||||
|
||||
/* Handle requested operation */
|
||||
switch (opt_ler) {
|
||||
|
||||
default: /* case OPT_r: Delete */
|
||||
remove(pas->pw_name);
|
||||
break;
|
||||
|
||||
case OPT_l: /* List */
|
||||
{
|
||||
char *args[2] = { pas->pw_name, NULL };
|
||||
return bb_cat(args);
|
||||
/* list exits,
|
||||
* the rest go play with cron update file */
|
||||
}
|
||||
|
||||
case OPT_e: /* Edit */
|
||||
tmp_fname = xasprintf(TMPDIR "/crontab.%u", (unsigned)getpid());
|
||||
fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
|
||||
xmove_fd(fd, STDIN_FILENO);
|
||||
fd = open(pas->pw_name, O_RDONLY);
|
||||
if (fd >= 0) {
|
||||
bb_copyfd_eof(fd, STDIN_FILENO);
|
||||
close(fd);
|
||||
}
|
||||
fchown(STDIN_FILENO, pas->pw_uid, pas->pw_gid);
|
||||
edit_file(pas, tmp_fname);
|
||||
xlseek(STDIN_FILENO, 0, SEEK_SET);
|
||||
/* fall through */
|
||||
|
||||
case 0: /* Replace (no -l, -e, or -r were given) */
|
||||
new_fname = xasprintf("%s.new", pas->pw_name);
|
||||
fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600);
|
||||
if (fd >= 0) {
|
||||
bb_copyfd_eof(STDIN_FILENO, fd);
|
||||
close(fd);
|
||||
rename(new_fname, pas->pw_name);
|
||||
} else {
|
||||
bb_error_msg("cannot create %s/%s",
|
||||
crontab_dir, new_fname);
|
||||
}
|
||||
if (tmp_fname)
|
||||
remove(tmp_fname);
|
||||
/*free(tmp_fname);*/
|
||||
/*free(new_fname);*/
|
||||
|
||||
} /* switch */
|
||||
|
||||
/* Bump notification file. Handle window where crond picks file up
|
||||
* before we can write our entry out.
|
||||
*/
|
||||
while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND)) >= 0) {
|
||||
struct stat st;
|
||||
|
||||
fdprintf(fd, "%s\n", pas->pw_name);
|
||||
if (fstat(fd, &st) != 0 || st.st_nlink != 0) {
|
||||
/*close(fd);*/
|
||||
break;
|
||||
}
|
||||
/* st.st_nlink == 0:
|
||||
* file was deleted, maybe crond missed our notification */
|
||||
close(fd);
|
||||
/* loop */
|
||||
}
|
||||
if (fd < 0) {
|
||||
bb_error_msg("cannot append to %s/%s",
|
||||
crontab_dir, CRONUPDATE);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user