/* Copyright 1988,1990,1993,1994 by Paul Vixie
* Distribute freely, except: don't remove my name from the source or
* documentation (don't take credit for my work), mark your changes (don't
* get me blamed for your possible bugs), don't alter or remove this
* notice. May be sold if buildable source is provided to buyer. No
* warrantee of any kind, express or implied, is included with this
* software; use at your own risk, responsibility for damages (if any) to
* anyone resulting from the use of this software rests entirely with the
* Send bug reports, bug fixes, enhancements, requests, flames, etc., and
* I'll try to keep a version up to date. I can be reached as follows:
* Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul
* from Id: do_command.c,v 2.12 1994/01/15 20:43:43 vixie Exp
#if !defined(lint) && !defined(LINT)
static char rcsid
[] = "$Header: $";
# include <sys/universe.h>
static void child_process
__P((entry
*, user
*)),
Debug(DPROC
, ("[%d] do_command(%s, (%s,%d,%d))\n",
getpid(), e
->cmd
, u
->name
, e
->uid
, e
->gid
))
/* fork to become asynchronous -- parent process is done immediately,
* and continues to run the normal cron code, which means return to
* tick(). the child and grandchild don't leave this function, alive.
* vfork() is unsuitable, since we have much to do, and the parent
* needs to be able to run off and fork other processes.
log_it("CRON",getpid(),"error","can't fork");
Debug(DPROC
, ("[%d] child process done, exiting\n", getpid()))
Debug(DPROC
, ("[%d] main process returning to work\n", getpid()))
int stdin_pipe
[2], stdout_pipe
[2];
register char *input_data
;
Debug(DPROC
, ("[%d] child_process('%s')\n", getpid(), e
->cmd
))
/* mark ourselves as different to PS command watchers by upshifting
* our program name. This has no effect on some kernels.
for (pch
= ProgramName
; *pch
; pch
++)
/* discover some useful and important environment settings
usernm
= env_get("LOGNAME", e
->envp
);
mailto
= env_get("MAILTO", e
->envp
);
/* our parent is watching for our death by catching SIGCHLD. we
* do not care to watch for our children's deaths this way -- we
* use wait() explictly. so we have to disable the signal (which
* was inherited from the parent).
(void) signal(SIGCHLD
, SIG_IGN
);
/* on system-V systems, we are ignoring SIGCLD. we have to stop
* ignoring it now or the wait() in cron_pclose() won't work.
* because of this, we have to wait() for our children here, as well.
(void) signal(SIGCLD
, SIG_DFL
);
/* create some pipes to talk to our future child
pipe(stdin_pipe
); /* child's stdin */
pipe(stdout_pipe
); /* child's stdout */
/* since we are a forked process, we can diddle the command string
* we were passed -- nobody else is going to use it again, right?
* if a % is present in the command, previous characters are the
* command, and subsequent characters are the additional input to
* the command. Subsequent %'s will be transformed into newlines,
* but that happens later.
register int escaped
= FALSE
;
for (input_data
= e
->cmd
; ch
= *input_data
; input_data
++) {
/* fork again, this time so we can exec the user's command.
log_it("CRON",getpid(),"error","can't vfork");
Debug(DPROC
, ("[%d] grandchild process Vfork()'ed\n",
/* write a log message. we've waited this long to do it
* because it was not until now that we knew the PID that
* the actual user command shell was going to get and the
* PID is part of the log message.
char *x
= mkprints((u_char
*)e
->cmd
, strlen(e
->cmd
));
log_it(usernm
, getpid(), "CMD", x
);
/* that's the last thing we'll log. close the log files.
/* get new pgrp, void tty, etc.
/* close the pipe ends that we won't use. this doesn't affect
* the parent, who has to read and write them; it keeps the
* kernel from recording us as a potential client TWICE --
* which would keep it from sending SIGPIPE in otherwise
* appropriate circumstances.
close(stdin_pipe
[WRITE_PIPE
]);
close(stdout_pipe
[READ_PIPE
]);
/* grandchild process. make std{in,out} be the ends of
* pipes opened by our daddy; make stderr go to stdout.
close(STDIN
); dup2(stdin_pipe
[READ_PIPE
], STDIN
);
close(STDOUT
); dup2(stdout_pipe
[WRITE_PIPE
], STDOUT
);
close(STDERR
); dup2(STDOUT
, STDERR
);
/* close the pipes we just dup'ed. The resources will remain.
close(stdin_pipe
[READ_PIPE
]);
close(stdout_pipe
[WRITE_PIPE
]);
/* set our login universe. Do this in the grandchild
* so that the child can invoke /usr/lib/sendmail
/* set our directory, uid and gid. Set gid first, since once
* we set uid, we've lost root privledges.
initgroups(env_get("LOGNAME", e
->envp
), e
->gid
);
setuid(e
->uid
); /* we aren't root after this... */
chdir(env_get("HOME", e
->envp
));
char *shell
= env_get("SHELL", e
->envp
);
if (DebugFlags
& DTEST
) {
"debug DTEST is on, not exec'ing command.\n");
"\tcmd='%s' shell='%s'\n", e
->cmd
, shell
);
execle(shell
, shell
, "-c", e
->cmd
, (char *)0, e
->envp
);
fprintf(stderr
, "execl: couldn't exec `%s'\n", shell
);
/* middle process, child of original cron, parent of process running
Debug(DPROC
, ("[%d] child continues, closing pipes\n", getpid()))
/* close the ends of the pipe that will only be referenced in the
close(stdin_pipe
[READ_PIPE
]);
close(stdout_pipe
[WRITE_PIPE
]);
* write, to the pipe connected to child's stdin, any input specified
* after a % in the crontab entry. while we copy, convert any
* additional %'s to newlines. when done, if some characters were
* written and the last one wasn't a newline, write a newline.
* Note that if the input data won't fit into one pipe buffer (2K
* or 4K on most BSD systems), and the child doesn't read its stdin,
* we would block here. thus we must fork again.
if (*input_data
&& fork() == 0) {
register FILE *out
= fdopen(stdin_pipe
[WRITE_PIPE
], "w");
register int need_newline
= FALSE
;
register int escaped
= FALSE
;
Debug(DPROC
, ("[%d] child2 sending data to grandchild\n", getpid()))
/* close the pipe we don't use, since we inherited it and
* are part of its reference count now.
close(stdout_pipe
[READ_PIPE
]);
* \x -> \x for all x != %
while (ch
= *input_data
++) {
if (!(escaped
= (ch
== '\\'))) {
need_newline
= (ch
!= '\n');
/* close the pipe, causing an EOF condition. fclose causes
* stdin_pipe[WRITE_PIPE] to be closed, too.
Debug(DPROC
, ("[%d] child2 done sending to grandchild\n", getpid()))
/* close the pipe to the grandkiddie's stdin, since its wicked uncle
* ernie back there has it open and will close it when he's done.
close(stdin_pipe
[WRITE_PIPE
]);
* read output from the grandchild. it's stderr has been redirected to
* it's stdout, which has been redirected to our pipe. if there is any
* output, we'll be mailing it to the user whose crontab this is...
* when the grandchild exits, we'll get EOF.
Debug(DPROC
, ("[%d] child reading output from grandchild\n", getpid()))
register FILE *in
= fdopen(stdout_pipe
[READ_PIPE
], "r");
register int ch
= getc(in
);
("[%d] got data (%x:%c) from grandchild\n",
/* get name of recipient. this is MAILTO if set to a
* valid local username; USER otherwise.
/* MAILTO was present in the environment
/* ... but it's empty. set to NULL
/* MAILTO not present, set to USER.
/* if we are supposed to be mailing, MAILTO will
* be non-NULL. only in this case should we set
* up the mail command and subjects and stuff...
auto char mailcmd
[MAX_COMMAND
];
auto char hostname
[MAXHOSTNAMELEN
];
(void) gethostname(hostname
, MAXHOSTNAMELEN
);
(void) sprintf(mailcmd
, MAILARGS
,
if (!(mail
= cron_popen(mailcmd
, "w"))) {
(void) _exit(ERROR_EXIT
);
fprintf(mail
, "From: root (Cron Daemon)\n");
fprintf(mail
, "To: %s\n", mailto
);
fprintf(mail
, "Subject: Cron <%s@%s> %s\n",
usernm
, first_word(hostname
, "."),
fprintf(mail
, "Date: %s\n",
for (env
= e
->envp
; *env
; env
++)
fprintf(mail
, "X-Cron-Env: <%s>\n",
/* this was the first char from the pipe
/* we have to read the input pipe no matter whether
* we mail or not, but obviously we only write to
* mail pipe if we ARE mailing.
while (EOF
!= (ch
= getc(in
))) {
/* only close pipe if we opened it -- i.e., we're
Debug(DPROC
, ("[%d] closing pipe to mail\n",
/* Note: the pclose will probably see
* the termination of the grandchild
* in addition to the mail process, since
* it (the grandchild) is likely to exit
* after closing its stdout.
status
= cron_pclose(mail
);
/* if there was output and we could not mail it,
* log the facts so the poor user can figure out
"mailed %d byte%s of output but got status 0x%04x\n",
bytes
, (bytes
==1)?"":"s",
log_it(usernm
, getpid(), "MAIL", buf
);
} /*if data from grandchild*/
Debug(DPROC
, ("[%d] got EOF from grandchild\n", getpid()))
fclose(in
); /* also closes stdout_pipe[READ_PIPE] */
/* wait for children to die.
for (; children
> 0; children
--)
Debug(DPROC
, ("[%d] waiting for grandchild #%d to finish\n",
Debug(DPROC
, ("[%d] no more grandchildren--mail written?\n",
Debug(DPROC
, ("[%d] grandchild #%d finished, status=%04x",
getpid(), pid
, WEXITSTATUS(waiter
)))
if (WIFSIGNALED(waiter
) && WCOREDUMP(waiter
))
Debug(DPROC
, (", dumped core"))
/* Dynix (Sequent) hack to put the user associated with
* the passed user structure into the ATT universe if
* necessary. We have to dig the gecos info out of
* the user's password entry to see if the magic
* "universe(att)" string is present.
if ((s
= strchr(s
, ',')) == NULL
)
if (strcmp(s
, "universe(att)"))