1 /*
2 * Copyright (c) 1988 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software written by Ken Arnold and
6 * published in UNIX Review, Vol. 6, No. 8.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the University of California, Berkeley. The name of the
14 * University may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 */
21
22 /* this came out of the ftpd sources; it's been modified to avoid the
23 * globbing stuff since we don't need it. also execvp instead of execv.
24 */
25
26 #ifndef lint
27 static const char rcsid[] =
28 "$Id: popen.c,v 1.3 1998/08/14 00:32:41 vixie Exp $";
29 #if 0
30 static const char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 2/14/89";
31 #endif
32 #endif /* not lint */
33
34 #include "cron.h"
35 #if defined(LOGIN_CAP)
36 # include <login_cap.h>
37 #endif
38
39 #define MAX_ARGS 100
40 #define WANT_GLOBBING 0
41
42 /*
43 * Special version of popen which avoids call to shell. This insures no one
44 * may create a pipe to a hidden program as a side effect of a list or dir
45 * command.
46 */
47 static PID_T *pids;
48 static int fds;
49
50 FILE *
cron_popen(char * program,char * type,entry * e,PID_T * pidptr)51 cron_popen(char *program, char *type, entry *e, PID_T *pidptr)
52 {
53 char *cp;
54 FILE *iop;
55 int argc, pdes[2];
56 PID_T pid;
57 char *usernm;
58 char *argv[MAX_ARGS + 1];
59 # if defined(LOGIN_CAP)
60 struct passwd *pwd;
61 login_cap_t *lc;
62 # endif
63 #if WANT_GLOBBING
64 char **pop, *vv[2];
65 int gargc;
66 char *gargv[1000];
67 extern char **glob(), **copyblk();
68 #endif
69
70 if ((*type != 'r' && *type != 'w') || type[1] != '\0')
71 return (NULL);
72
73 if (!pids) {
74 if ((fds = sysconf(_SC_OPEN_MAX)) <= 0)
75 return (NULL);
76 if (!(pids = calloc(fds, sizeof(PID_T))))
77 return (NULL);
78 }
79 if (pipe(pdes) < 0)
80 return (NULL);
81
82 /* break up string into pieces */
83 for (argc = 0, cp = program; argc < MAX_ARGS; cp = NULL)
84 if (!(argv[argc++] = strtok(cp, " \t\n")))
85 break;
86 argv[MAX_ARGS] = NULL;
87
88 #if WANT_GLOBBING
89 /* glob each piece */
90 gargv[0] = argv[0];
91 for (gargc = argc = 1; argv[argc]; argc++) {
92 if (!(pop = glob(argv[argc]))) { /* globbing failed */
93 vv[0] = argv[argc];
94 vv[1] = NULL;
95 pop = copyblk(vv);
96 }
97 argv[argc] = (char *)pop; /* save to free later */
98 while (*pop && gargc < 1000)
99 gargv[gargc++] = *pop++;
100 }
101 gargv[gargc] = NULL;
102 #endif
103
104 iop = NULL;
105 switch(pid = fork()) {
106 case -1: /* error */
107 (void)close(pdes[0]);
108 (void)close(pdes[1]);
109 goto pfree;
110 /* NOTREACHED */
111 case 0: /* child */
112 if (e != NULL) {
113 #ifdef SYSLOG
114 closelog();
115 #endif
116
117 /* get new pgrp, void tty, etc.
118 */
119 (void) setsid();
120 }
121 if (*type == 'r') {
122 /* Do not share our parent's stdin */
123 (void)close(0);
124 (void)open(_PATH_DEVNULL, O_RDWR);
125 if (pdes[1] != 1) {
126 dup2(pdes[1], 1);
127 dup2(pdes[1], 2); /* stderr, too! */
128 (void)close(pdes[1]);
129 }
130 (void)close(pdes[0]);
131 } else {
132 if (pdes[0] != 0) {
133 dup2(pdes[0], 0);
134 (void)close(pdes[0]);
135 }
136 /* Hack: stdout gets revoked */
137 (void)close(1);
138 (void)open(_PATH_DEVNULL, O_RDWR);
139 (void)close(2);
140 (void)open(_PATH_DEVNULL, O_RDWR);
141 (void)close(pdes[1]);
142 }
143 if (e != NULL) {
144 /* Set user's entire context, but skip the environment
145 * as cron provides a separate interface for this
146 */
147 usernm = env_get("LOGNAME", e->envp);
148 # if defined(LOGIN_CAP)
149 if ((pwd = getpwnam(usernm)) == NULL)
150 pwd = getpwuid(e->uid);
151 lc = NULL;
152 if (pwd != NULL) {
153 pwd->pw_gid = e->gid;
154 if (e->class != NULL)
155 lc = login_getclass(e->class);
156 }
157 if (pwd &&
158 setusercontext(lc, pwd, e->uid,
159 LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0)
160 (void) endpwent();
161 else {
162 /* fall back to the old method */
163 (void) endpwent();
164 # endif
165 /*
166 * Set our directory, uid and gid. Set gid
167 * first since once we set uid, we've lost
168 * root privileges.
169 */
170 if (setgid(e->gid) != 0)
171 _exit(ERROR_EXIT);
172 # if defined(BSD)
173 if (initgroups(usernm, e->gid) != 0)
174 _exit(ERROR_EXIT);
175 # endif
176 if (setlogin(usernm) != 0)
177 _exit(ERROR_EXIT);
178 if (setuid(e->uid) != 0)
179 _exit(ERROR_EXIT);
180 /* we aren't root after this..*/
181 #if defined(LOGIN_CAP)
182 }
183 if (lc != NULL)
184 login_close(lc);
185 #endif
186 chdir(env_get("HOME", e->envp));
187 }
188 #if WANT_GLOBBING
189 execvp(gargv[0], gargv);
190 #else
191 execvp(argv[0], argv);
192 #endif
193 _exit(1);
194 }
195 /* parent; assume fdopen can't fail... */
196 if (*type == 'r') {
197 iop = fdopen(pdes[0], type);
198 (void)close(pdes[1]);
199 } else {
200 iop = fdopen(pdes[1], type);
201 (void)close(pdes[0]);
202 }
203 pids[fileno(iop)] = pid;
204
205 pfree:
206 #if WANT_GLOBBING
207 for (argc = 1; argv[argc] != NULL; argc++) {
208 /* blkfree((char **)argv[argc]); */
209 free((char *)argv[argc]);
210 }
211 #endif
212
213 *pidptr = pid;
214
215 return (iop);
216 }
217
218 int
cron_pclose(FILE * iop)219 cron_pclose(FILE *iop)
220 {
221 int fdes;
222 int omask;
223 WAIT_T stat_loc;
224 PID_T pid;
225
226 /*
227 * pclose returns -1 if stream is not associated with a
228 * `popened' command, or, if already `pclosed'.
229 */
230 if (pids == 0 || pids[fdes = fileno(iop)] == 0)
231 return (-1);
232 (void)fclose(iop);
233 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
234 while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1)
235 ;
236 (void)sigsetmask(omask);
237 pids[fdes] = 0;
238 return (pid == -1 ? -1 : WEXITSTATUS(stat_loc));
239 }
240