diff options
Diffstat (limited to 'system_cmds/atrun.tproj/atrun.c')
| -rw-r--r-- | system_cmds/atrun.tproj/atrun.c | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/system_cmds/atrun.tproj/atrun.c b/system_cmds/atrun.tproj/atrun.c new file mode 100644 index 0000000..0981614 --- /dev/null +++ b/system_cmds/atrun.tproj/atrun.c @@ -0,0 +1,571 @@ +/* + * atrun.c - run jobs queued by at; run with root privileges. + * Copyright (C) 1993, 1994 Thomas Koenig + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. The name of the author(s) may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +#ifndef lint +__FBSDID("$FreeBSD: src/libexec/atrun/atrun.c,v 1.27 2009/12/25 10:30:54 ed Exp $"); +#endif /* not lint */ + +/* System Headers */ + +#include <sys/fcntl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <sys/param.h> +#include <ctype.h> +#include <dirent.h> +#include <err.h> +#include <grp.h> +#include <pwd.h> +#include <signal.h> +#include <stdarg.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> +#include <time.h> +#include <unistd.h> +#if 1 +#include <paths.h> +#else +#include <getopt.h> +#endif +#ifdef LOGIN_CAP +#include <login_cap.h> +#endif +#ifdef PAM +#include <security/pam_appl.h> +#include <security/openpam.h> +#endif + +/* Local headers */ + +#define MAIN +#include "privs.h" +#include "pathnames.h" + +/* Macros */ + +#ifndef ATJOB_DIR +#define ATJOB_DIR _PATH_ATJOBS +#endif + +#ifndef ATSPOOL_DIR +#define ATSPOOL_DIR _PATH_ATSPOOL +#endif + +#ifndef LOADAVG_MX +#define LOADAVG_MX 1.5 +#endif + +/* File scope variables */ + +static const char * const atrun = "atrun"; /* service name for syslog etc. */ +static int debug = 0; + +void perr(const char *fmt, ...); +void perrx(const char *fmt, ...); +static void usage(void); + +/* Local functions */ +static ssize_t +write_string(int fd, const char* a) +{ + return write(fd, a, strlen(a)); +} + +#undef DEBUG_FORK +#ifdef DEBUG_FORK +static pid_t +myfork(void) +{ + pid_t res; + res = fork(); + if (res == 0) + kill(getpid(),SIGSTOP); + return res; +} + +#define fork myfork +#endif + +static void +run_file(const char *filename, uid_t uid, gid_t gid) +{ +/* Run a file by spawning off a process which redirects I/O, + * spawns a subshell, then waits for it to complete and sends + * mail to the user. + */ + pid_t pid; + int fd_out, fd_in; + int queue; + char mailbuf[MAXLOGNAME], fmt[64]; + char *mailname = NULL; + FILE *stream; + int send_mail = 0; + struct stat buf, lbuf; + off_t size; + struct passwd *pentry; + int fflags; + long nuid; + long ngid; +#ifdef PAM + pam_handle_t *pamh = NULL; + int pam_err; + struct pam_conv pamc = { + .conv = openpam_nullconv, + .appdata_ptr = NULL + }; +#endif + + PRIV_START + + if (chmod(filename, S_IRUSR) != 0) + { + perr("cannot change file permissions"); + } + + PRIV_END + + pid = fork(); + if (pid == -1) + perr("cannot fork"); + + else if (pid != 0) + return; + +#ifdef __APPLE__ + { + pid_t pg = setsid(); + if (pg == -1) syslog(LOG_ERR,"setsid() failed: %m"); + } +#endif + + /* Let's see who we mail to. Hopefully, we can read it from + * the command file; if not, send it to the owner, or, failing that, + * to root. + */ + + pentry = getpwuid(uid); + if (pentry == NULL) + perrx("Userid %lu not found - aborting job %s", + (unsigned long) uid, filename); + +#ifdef PAM + PRIV_START + + pam_err = pam_start(atrun, pentry->pw_name, &pamc, &pamh); + if (pam_err != PAM_SUCCESS) + perrx("cannot start PAM: %s", pam_strerror(pamh, pam_err)); + + pam_err = pam_acct_mgmt(pamh, PAM_SILENT); + /* Expired password shouldn't prevent the job from running. */ + if (pam_err != PAM_SUCCESS && pam_err != PAM_NEW_AUTHTOK_REQD) + perrx("Account %s (userid %lu) unavailable for job %s: %s", + pentry->pw_name, (unsigned long)uid, + filename, pam_strerror(pamh, pam_err)); + + pam_end(pamh, pam_err); + + PRIV_END +#endif /* PAM */ + + PRIV_START + + stream=fopen(filename, "r"); + + PRIV_END + + if (stream == NULL) + perr("cannot open input file"); + + if ((fd_in = dup(fileno(stream))) <0) + perr("error duplicating input file descriptor"); + + if (fstat(fd_in, &buf) == -1) + perr("error in fstat of input file descriptor"); + + if (lstat(filename, &lbuf) == -1) + perr("error in fstat of input file"); + + if (S_ISLNK(lbuf.st_mode)) + perrx("Symbolic link encountered in job %s - aborting", filename); + + if ((lbuf.st_dev != buf.st_dev) || (lbuf.st_ino != buf.st_ino) || + (lbuf.st_uid != buf.st_uid) || (lbuf.st_gid != buf.st_gid) || + (lbuf.st_size!=buf.st_size)) + perrx("Somebody changed files from under us for job %s - aborting", + filename); + + if (buf.st_nlink > 1) + perrx("Somebody is trying to run a linked script for job %s", filename); + + if ((fflags = fcntl(fd_in, F_GETFD)) <0) + perr("error in fcntl"); + + fcntl(fd_in, F_SETFD, fflags & ~FD_CLOEXEC); + + snprintf(fmt, sizeof(fmt), + "#!/bin/sh\n# atrun uid=%%ld gid=%%ld\n# mail %%%ds %%d", + MAXLOGNAME - 1); + + if (fscanf(stream, fmt, &nuid, &ngid, mailbuf, &send_mail) != 4) + perrx("File %s is in wrong format - aborting", filename); + + if (mailbuf[0] == '-') + perrx("Illegal mail name %s in %s", mailbuf, filename); + + mailname = mailbuf; + + if (nuid != uid) + perrx("Job %s - userid %ld does not match file uid %lu", + filename, nuid, (unsigned long)uid); + + if (ngid != gid) + perrx("Job %s - groupid %ld does not match file gid %lu", + filename, ngid, (unsigned long)gid); + + fclose(stream); + + if (chdir(ATSPOOL_DIR) < 0) + perr("cannot chdir to %s", ATSPOOL_DIR); + + /* Create a file to hold the output of the job we are about to run. + * Write the mail header. + */ + if((fd_out=open(filename, + O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR)) < 0) + perr("cannot create output file"); + + write_string(fd_out, "Subject: Output from your job "); + write_string(fd_out, filename); + write_string(fd_out, "\n\n"); + fstat(fd_out, &buf); + size = buf.st_size; + + close(STDIN_FILENO); + close(STDOUT_FILENO); + close(STDERR_FILENO); + + pid = fork(); + if (pid < 0) + perr("error in fork"); + + else if (pid == 0) + { + char *nul = NULL; + char **nenvp = &nul; + + /* Set up things for the child; we want standard input from the input file, + * and standard output and error sent to our output file. + */ + + if (lseek(fd_in, (off_t) 0, SEEK_SET) < 0) + perr("error in lseek"); + + if (dup(fd_in) != STDIN_FILENO) + perr("error in I/O redirection"); + + if (dup(fd_out) != STDOUT_FILENO) + perr("error in I/O redirection"); + + if (dup(fd_out) != STDERR_FILENO) + perr("error in I/O redirection"); + + close(fd_in); + close(fd_out); + if (chdir(ATJOB_DIR) < 0) + perr("cannot chdir to %s", ATJOB_DIR); + + queue = *filename; + + PRIV_START + + nice(tolower(queue) - 'a'); + +#ifdef LOGIN_CAP + /* + * For simplicity and safety, set all aspects of the user context + * except for a selected subset: Don't set priority, which was + * set based on the queue file name according to the tradition. + * Don't bother to set environment, including path vars, either + * because it will be discarded anyway. Although the job file + * should set umask, preset it here just in case. + */ + if (setusercontext(NULL, pentry, uid, LOGIN_SETALL & + ~(LOGIN_SETPRIORITY | LOGIN_SETPATH | LOGIN_SETENV)) != 0) + exit(EXIT_FAILURE); /* setusercontext() logged the error */ +#else /* LOGIN_CAP */ + if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0) + perr("cannot change group"); + + if (initgroups(pentry->pw_name,pentry->pw_gid)) + perr("cannot init group access list"); + + if (setlogin(pentry->pw_name)) + perr("cannot set login name"); + + if (setuid(uid) < 0 || seteuid(uid) < 0) + perr("cannot set user id"); +#endif /* LOGIN_CAP */ + + if (chdir(pentry->pw_dir)) + chdir("/"); + + if(execle("/bin/sh","sh",(char *) NULL, nenvp) != 0) + perr("exec failed for /bin/sh"); + + PRIV_END + } + /* We're the parent. Let's wait. + */ + close(fd_in); + close(fd_out); + waitpid(pid, (int *) NULL, 0); + + /* Send mail. Unlink the output file first, so it is deleted after + * the run. + */ + stat(filename, &buf); + if (open(filename, O_RDONLY) != STDIN_FILENO) + perr("open of jobfile failed"); + + unlink(filename); + if ((buf.st_size != size) || send_mail) + { + PRIV_START + +#ifdef LOGIN_CAP + /* + * This time set full context to run the mailer. + */ + if (setusercontext(NULL, pentry, uid, LOGIN_SETALL) != 0) + exit(EXIT_FAILURE); /* setusercontext() logged the error */ +#else /* LOGIN_CAP */ + if (setgid(gid) < 0 || setegid(pentry->pw_gid) < 0) + perr("cannot change group"); + + if (initgroups(pentry->pw_name,pentry->pw_gid)) + perr("cannot init group access list"); + + if (setlogin(pentry->pw_name)) + perr("cannot set login name"); + + if (setuid(uid) < 0 || seteuid(uid) < 0) + perr("cannot set user id"); +#endif /* LOGIN_CAP */ + + if (chdir(pentry->pw_dir)) + chdir("/"); + +#if 1 + execl(_PATH_SENDMAIL, "sendmail", "-F", "Atrun Service", + "-odi", "-oem", + mailname, (char *) NULL); +#else + execl(MAIL_CMD, MAIL_CMD, mailname, (char *) NULL); +#endif + perr("exec failed for mail command"); + + PRIV_END + } + exit(EXIT_SUCCESS); +} + +/* Global functions */ + +/* Needed in gloadavg.c */ +void +perr(const char *fmt, ...) +{ + const char * const fmtadd = ": %m"; + char nfmt[strlen(fmt) + strlen(fmtadd) + 1]; + va_list ap; + + va_start(ap, fmt); + if (debug) + { + vwarn(fmt, ap); + } + else + { + snprintf(nfmt, sizeof(nfmt), "%s%s", fmt, fmtadd); + vsyslog(LOG_ERR, nfmt, ap); + } + va_end(ap); + + exit(EXIT_FAILURE); +} + +void +perrx(const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + if (debug) + vwarnx(fmt, ap); + else + vsyslog(LOG_ERR, fmt, ap); + va_end(ap); + + exit(EXIT_FAILURE); +} + +int +main(int argc, char *argv[]) +{ +/* Browse through ATJOB_DIR, checking all the jobfiles wether they should + * be executed and or deleted. The queue is coded into the first byte of + * the job filename, the date (in minutes since Eon) as a hex number in the + * following eight bytes, followed by a dot and a serial number. A file + * which has not been executed yet is denoted by its execute - bit set. + * For those files which are to be executed, run_file() is called, which forks + * off a child which takes care of I/O redirection, forks off another child + * for execution and yet another one, optionally, for sending mail. + * Files which already have run are removed during the next invocation. + */ + DIR *spool; + struct dirent *dirent; + struct stat buf; + unsigned long ctm; + unsigned long jobno; + char queue; + time_t now, run_time; + char batch_name[] = "Z2345678901234"; + uid_t batch_uid; + gid_t batch_gid; + int c; + int run_batch; + double load_avg = LOADAVG_MX, la; + +/* We don't need root privileges all the time; running under uid and gid daemon + * is fine. + */ + + RELINQUISH_PRIVS_ROOT(DAEMON_UID, DAEMON_GID) + + openlog(atrun, LOG_PID, LOG_CRON); + + opterr = 0; + while((c=getopt(argc, argv, "dl:"))!= -1) + { + switch (c) + { + case 'l': + if (sscanf(optarg, "%lf", &load_avg) != 1) + perr("garbled option -l"); + if (load_avg <= 0.) + load_avg = LOADAVG_MX; + break; + + case 'd': + debug ++; + break; + + case '?': + default: + usage(); + } + } + + if (chdir(ATJOB_DIR) != 0) + perr("cannot change to %s", ATJOB_DIR); + + /* Main loop. Open spool directory for reading and look over all the + * files in there. If the filename indicates that the job should be run + * and the x bit is set, fork off a child which sets its user and group + * id to that of the files and exec a /bin/sh which executes the shell + * script. Unlink older files if they should no longer be run. For + * deletion, their r bit has to be turned on. + * + * Also, pick the oldest batch job to run, at most one per invocation of + * atrun. + */ + if ((spool = opendir(".")) == NULL) + perr("cannot read %s", ATJOB_DIR); + + now = time(NULL); + run_batch = 0; + batch_uid = (uid_t) -1; + batch_gid = (gid_t) -1; + + while ((dirent = readdir(spool)) != NULL) { + if (stat(dirent->d_name,&buf) != 0) + perr("cannot stat in %s", ATJOB_DIR); + + /* We don't want directories + */ + if (!S_ISREG(buf.st_mode)) + continue; + + if (sscanf(dirent->d_name,"%c%5lx%8lx",&queue,&jobno,&ctm) != 3) + continue; + + run_time = (time_t) ctm*60; + + if ((S_IXUSR & buf.st_mode) && (run_time <=now)) { + if ((isupper(queue) || queue == 'b') && (strcmp(batch_name,dirent->d_name) > 0)) { + run_batch = 1; + strlcpy(batch_name, dirent->d_name, sizeof(batch_name)); + batch_uid = buf.st_uid; + batch_gid = buf.st_gid; + } + + /* The file is executable and old enough + */ + if (islower(queue)) + run_file(dirent->d_name, buf.st_uid, buf.st_gid); + } + /* Delete older files + */ + if ((run_time < now) && !(S_IXUSR & buf.st_mode) && (S_IRUSR & buf.st_mode)) + unlink(dirent->d_name); + } + /* run the single batch file, if any + */ + if (run_batch && (getloadavg(&la, 1) == 1) && la < load_avg) + run_file(batch_name, batch_uid, batch_gid); + + closelog(); +#if __APPLE__ + // allow enough time for child processes to call setsid(2) + sleep(1); +#endif + exit(EXIT_SUCCESS); +} + +static void +usage(void) +{ + if (debug) + fprintf(stderr, "usage: atrun [-l load_avg] [-d]\n"); + else + syslog(LOG_ERR, "usage: atrun [-l load_avg] [-d]"); + + exit(EXIT_FAILURE); +} |