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Fixes for crontab and crond
[unix-history] / usr / src / libexec / crond / do_command.c
#if !defined(lint) && !defined(LINT)
static char rcsid[] = "$Header: do_command.c,v 2.1 90/07/18 00:23:38 vixie Exp $";
#endif
/* $Source: /jove_u3/vixie/src/cron/RCS/do_command.c,v $
* $Revision: 2.1 $
* $Log: do_command.c,v $
* Revision 2.1 90/07/18 00:23:38 vixie
* Baseline for 4.4BSD release
*
* Revision 2.0 88/12/10 04:57:44 vixie
* V2 Beta
*
* Revision 1.5 88/11/29 13:06:06 vixie
* seems to work on Ultrix 3.0 FT1
*
* Revision 1.4 87/05/02 17:33:35 paul
* baseline for mod.sources release
*
* Revision 1.3 87/04/09 00:03:58 paul
* improved data hiding, locality of declaration/references
* fixed a rs@mirror bug by redesigning the mailto stuff completely
*
* Revision 1.2 87/03/19 12:46:24 paul
* implemented suggestions from rs@mirror (Rich $alz):
* MAILTO="" means no mail should be sent
* various fixes of bugs or lint complaints
* put a To: line in the mail message
*
* Revision 1.1 87/01/26 23:47:00 paul
* Initial revision
*
* PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
* -------------------- ----- ----------------------
* CURRENT PATCH LEVEL: 1 00131
* -------------------- ----- ----------------------
*
* 06 Apr 93 Adam Glass Fixes so it compiles quitely
*
*/
/* Copyright 1988,1990 by Paul Vixie
* All rights reserved
*
* 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
* user.
*
* 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, 329 Noe Street, San Francisco, CA, 94114, (415) 864-7013,
* paul@vixie.sf.ca.us || {hoptoad,pacbell,decwrl,crash}!vixie!paul
*/
#include "cron.h"
#include <signal.h>
#include <pwd.h>
#if defined(BSD)
# include <sys/wait.h>
#endif /*BSD*/
#if defined(sequent)
# include <strings.h>
# include <sys/universe.h>
#endif
void
do_command(cmd, u)
char *cmd;
user *u;
{
extern int fork(), _exit();
extern void child_process(), log_it();
extern char *env_get();
Debug(DPROC, ("[%d] do_command(%s, (%s,%d,%d))\n",
getpid(), cmd, env_get(USERENV, u->envp), u->uid, u->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.
*/
switch (fork())
{
case -1:
log_it("CROND",getpid(),"error","can't fork");
break;
case 0:
/* child process */
child_process(cmd, u);
Debug(DPROC, ("[%d] child process done, exiting\n", getpid()))
_exit(OK_EXIT);
break;
}
Debug(DPROC, ("[%d] main process returning to work\n", getpid()))
}
void
child_process(cmd, u)
char *cmd;
user *u;
{
extern struct passwd *getpwnam();
extern void sigpipe_func(), be_different(), log_it();
extern int VFORK();
extern char *index(), *env_get();
auto int stdin_pipe[2], stdout_pipe[2];
register char *input_data, *usernm, *mailto;
auto int children = 0;
#if defined(sequent)
extern void do_univ();
#endif
Debug(DPROC, ("[%d] child_process('%s')\n", getpid(), cmd))
/* mark ourselves as different to PS command watchers by upshifting
* our program name. This has no effect on some kernels.
*/
{
register char *pch;
for (pch = ProgramName; *pch; pch++)
*pch = MkUpper(*pch);
}
/* discover some useful and important environment settings
*/
usernm = env_get(USERENV, u->envp);
mailto = env_get("MAILTO", u->envp);
#if defined(BSD)
/* 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).
*
* this isn't needed for system V, since our parent is already
* SIG_IGN on SIGCLD -- which, hopefully, will cause children to
* simply vanish when they die.
*/
(void) signal(SIGCHLD, SIG_IGN);
#endif /*BSD*/
/* 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.
*/
if (NULL == (input_data = index(cmd, '%')))
{
/* no %. point input_data at a null string.
*/
input_data = "";
}
else
{
/* % found. replace with a null (remember, we're a forked
* process and the string won't be reused), and increment
* input_data to point at the following character.
*/
*input_data++ = '\0';
}
/* fork again, this time so we can exec the user's command. Vfork()
* is okay this time, since we are going to exec() pretty quickly.
* I'm assuming that closing pipe ends &whatnot will not affect our
* suspended pseudo-parent/alter-ego.
*/
if (VFORK() == 0)
{
Debug(DPROC, ("[%d] grandchild process VFORK()'ed\n", getpid()))
/* 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.
*/
#ifdef LOG_FILE
{
extern char *mkprints();
char *x = mkprints(cmd, strlen(cmd));
log_it(usernm, getpid(), "CMD", x);
free(x);
}
#endif
/* get new pgrp, void tty, etc.
*/
be_different();
/* 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,
* since they've been dup'ed... :-)...
*/
close(stdin_pipe[READ_PIPE]);
close(stdout_pipe[WRITE_PIPE]);
# if defined(sequent)
/* set our login universe. Do this in the grandchild
* so that the child can invoke /usr/lib/sendmail
* without surprises.
*/
do_univ(u);
# endif
/* set our directory, uid and gid. Set gid first, since once
* we set uid, we've lost root privledges. (oops!)
*/
setgid(u->gid);
# if defined(BSD)
initgroups(env_get(USERENV, u->envp), u->gid);
# endif
setuid(u->uid); /* you aren't root after this... */
chdir(env_get("HOME", u->envp));
/* exec the command.
*/
{
char *shell = env_get("SHELL", u->envp);
# if DEBUGGING
if (DebugFlags & DTEST) {
fprintf(stderr,
"debug DTEST is on, not exec'ing command.\n");
fprintf(stderr,
"\tcmd='%s' shell='%s'\n", cmd, shell);
_exit(OK_EXIT);
}
# endif /*DEBUGGING*/
/* normally you can't put debugging stuff here because
* it gets mailed with the command output.
*/
/*
Debug(DPROC, ("[%d] execle('%s', '%s', -c, '%s')\n",
getpid(), shell, shell, cmd))
*/
# ifdef bad_idea
/* files writable by non-owner are a no-no
*/
{
struct stat sb;
if (0 != stat(cmd, &sb)) {
fputs("crond: stat(2): ", stderr);
perror(cmd);
_exit(ERROR_EXIT);
} else if (sb.st_mode & 022) {
fprintf(stderr,
"crond: %s writable by nonowner\n",
cmd);
_exit(ERROR_EXIT);
} else if (sb.st_uid & 022) {
fprintf(stderr,
"crond: %s owned by uid %d\n",
cmd, sb.st_uid);
_exit(ERROR_EXIT);
}
}
# endif /*bad_idea*/
execle(shell, shell, "-c", cmd, (char *)0, u->envp);
fprintf(stderr, "execl: couldn't exec `%s'\n", shell);
perror("execl");
_exit(ERROR_EXIT);
}
}
children++;
/* middle process, child of original cron, parent of process running
* the user's command.
*/
Debug(DPROC, ("[%d] child continues, closing pipes\n", getpid()))
/* close the ends of the pipe that will only be referenced in the
* grandchild process...
*/
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. the solution, of course, is to 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;
register int ch;
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]);
/* translation:
* \% -> %
* % -> \n
* \x -> \x for all x != %
*/
while (ch = *input_data++)
{
if (escaped) {
if (ch != '%')
putc('\\', out);
} else {
if (ch == '%')
ch = '\n';
}
if (!(escaped = (ch == '\\'))) {
putc(ch, out);
need_newline = (ch != '\n');
}
}
if (escaped)
putc('\\', out);
if (need_newline)
putc('\n', out);
/* close the pipe, causing an EOF condition. fclose causes
* stdin_pipe[WRITE_PIPE] to be closed, too.
*/
fclose(out);
Debug(DPROC, ("[%d] child2 done sending to grandchild\n", getpid()))
exit(0);
}
/* 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]);
children++;
/*
* 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);
if (ch != EOF)
{
register FILE *mail;
register int bytes = 1;
union wait status;
Debug(DPROC|DEXT,
("[%d] got data (%x:%c) from grandchild\n",
getpid(), ch, ch))
/* get name of recipient. this is MAILTO if set to a
* valid local username; USER otherwise.
*/
if (mailto)
{
/* MAILTO was present in the environment
*/
if (!*mailto)
{
/* ... but it's empty. set to NULL
*/
mailto = NULL;
}
}
else
{
/* MAILTO not present, set to USER.
*/
mailto = usernm;
}
/* 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...
*/
if (mailto)
{
extern FILE *popen();
extern char *print_cmd();
register char **env;
auto char mailcmd[MAX_COMMAND];
auto char hostname[MAXHOSTNAMELEN];
(void) gethostname(hostname, MAXHOSTNAMELEN);
(void) sprintf(mailcmd, MAILCMD, mailto);
if (!(mail = popen(mailcmd, "w")))
{
perror(MAILCMD);
(void) _exit(ERROR_EXIT);
}
fprintf(mail, "From: root (Cron Daemon)\n");
fprintf(mail, "To: %s\n", mailto);
fprintf(mail,
"Subject: cron for %s@%s said this\n",
usernm, first_word(hostname, ".")
);
fprintf(mail, "Date: %s", ctime(&TargetTime));
fprintf(mail, "X-Cron-Cmd: <%s>\n", cmd);
for (env = u->envp; *env; env++)
fprintf(mail, "X-Cron-Env: <%s>\n",
*env);
fprintf(mail, "\n");
/* this was the first char from the pipe
*/
putc(ch, mail);
}
/* 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)))
{
bytes++;
if (mailto)
putc(ch, mail);
}
/* only close pipe if we opened it -- i.e., we're
* mailing...
*/
if (mailto) {
Debug(DPROC, ("[%d] closing pipe to mail\n",
getpid()))
/* 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.w_status = pclose(mail);
}
/* if there was output and we could not mail it,
* log the facts so the poor user can figure out
* what's going on.
*/
if (mailto && status.w_status) {
char buf[MAX_TEMPSTR];
sprintf(buf,
"mailed %d byte%s of output but got status 0x%04x\n",
bytes, (bytes==1)?"":"s",
status.w_status);
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] */
}
#if defined(BSD)
/* wait for children to die.
*/
for (; children > 0; children--)
{
int pid;
union wait waiter;
Debug(DPROC, ("[%d] waiting for grandchild #%d to finish\n",
getpid(), children))
pid = wait((int *) &waiter);
if (pid < OK) {
Debug(DPROC, ("[%d] no more grandchildren--mail written?\n",
getpid()))
break;
}
Debug(DPROC, ("[%d] grandchild #%d finished, status=%04x",
getpid(), pid, waiter.w_status))
if (waiter.w_coredump)
Debug(DPROC, (", dumped core"))
Debug(DPROC, ("\n"))
}
#endif /*BSD*/
}
#if defined(sequent)
/* 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 we do change
* the universe, also set "LOGNAME".
*/
void
do_univ(u)
user *u;
{
struct passwd *p;
char *s;
int i;
char envstr[MAX_ENVSTR], **env_set();
p = getpwuid(u->uid);
(void) endpwent();
if (p == NULL)
return;
s = p->pw_gecos;
for (i = 0; i < 4; i++)
{
if ((s = index(s, ',')) == NULL)
return;
s++;
}
if (strcmp(s, "universe(att)"))
return;
(void) sprintf(envstr, "LOGNAME=%s", p->pw_name);
u->envp = env_set(u->envp, envstr);
(void) universe(U_ATT);
}
#endif
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.