3 * daemon code which executes actual service (ie child process)
5 * userv is copyright Ian Jackson and other contributors.
6 * See README for full authorship information.
8 * This is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 3 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with userv; if not, see <http://www.gnu.org/licenses/>.
30 #include <sys/types.h>
41 static void NONRETURNING serv_syscallfail(const char *msg) {
42 fputs("uservd(service): ",stderr);
47 static void NONRETURNING serv_checkstdoutexit(void) {
48 if (ferror(stdout) || fclose(stdout)) serv_syscallfail("write stdout");
52 void bisexec_environment(const char *const *argv) {
53 execlp("env","env",(char*)0);
54 serv_syscallfail("execute `env'");
57 void bisexec_parameter(const char *const *argv) {
58 always_dumpparameter(execargs[0],execargs+1);
59 serv_checkstdoutexit();
62 void bisexec_help(const char *const *argv) {
63 const char *const *pp;
65 fputs("recognised builtin services:\n",stdout);
66 for (pp= builtinservicehelpstrings; *pp; pp++) printf(" %s\n",*pp);
67 serv_checkstdoutexit();
70 void bisexec_version(const char *const *argv) {
71 const unsigned char *p;
74 printf("uservd version " VERSION VEREXT "\n"
80 " - protocol magic number %08lx\n"
81 "maximums: fd %-10d general string %d\n"
82 " gids %-10d override length %d\n"
83 " args or variables %-10d error message %d\n"
84 " nested inclusion %-10d errno string reserve %d\n"
85 "protocol checksum: ",
87 MAX_ALLOW_FD, MAX_GENERAL_STRING,
88 MAX_GIDS, MAX_OVERRIDE_LEN,
89 MAX_ARGSDEFVAR, MAX_ERRMSG_LEN,
90 MAX_INCLUDE_NEST, ERRMSG_RESERVE_ERRNO);
91 for (i=0, p=protocolchecksumversion; i<sizeof(protocolchecksumversion); i++, p++)
94 "rendezvous socket: `" RENDEZVOUSPATH "'\n"
95 "system config dir: `" SYSTEMCONFIGDIR "'\n"
96 "pipe filename format: `%s' (max length %d)\n"
98 PIPEFORMAT, PIPEMAXLEN);
99 serv_checkstdoutexit();
102 static void NONRETURNING dumpconfig(const char *string) {
107 while ((c= *string++)) {
109 case ' ': nspaces++; break;
111 if (!lnl) putchar('\n');
115 while (nspaces>0) { putchar(' '); nspaces--; }
122 serv_checkstdoutexit();
125 void bisexec_toplevel(const char *const *argv) {
126 dumpconfig(TOPLEVEL_CONFIGURATION);
129 void bisexec_override(const char *const *argv) {
130 dumpconfig(TOPLEVEL_OVERRIDDEN_CONFIGURATION);
133 void bisexec_reset(const char *const *argv) {
134 dumpconfig(RESET_CONFIGURATION);
137 void bisexec_execute(const char *const *argv) {
138 always_dumpexecsettings();
139 serv_checkstdoutexit();
142 void bisexec_shutdown(const char *const *argv) {
143 /* This is only reached if the serviceuser_uid test in
144 * process.c:servicerequest() fails (we have to handle the
145 * shutdown request there, unfortunately).
147 fputs("uservd: builtin service shutdown: permission denied\n",stderr);
151 static void serv_resetsignal(int signo) {
152 struct sigaction sig;
154 sig.sa_handler= SIG_DFL;
155 sigemptyset(&sig.sa_mask);
157 if (sigaction(signo,&sig,0)) serv_syscallfail("reset signal handler");
160 static const char *see_loginname(void) { return serviceuser; }
161 static const char *see_home(void) { return serviceuser_dir; }
162 static const char *see_shell(void) { return serviceuser_shell; }
164 static const char *see_service(void) { return service; }
165 static const char *see_c_cwd(void) { return cwd; }
166 static const char *see_c_loginname(void) { return loginname; }
167 static const char *see_c_uid(void) {
168 static char buf[CHAR_BIT*sizeof(uid_t)/3+4];
169 snyprintf(buf,sizeof(buf),"%lu",(unsigned long)request_mbuf.callinguid);
173 static const char *see_c_list(int n, const char *(*fn)(int i)) {
177 for (i=0, l=1; i<n; i++) l+= strlen(fn(i))+1;
178 r= xmalloc(l); r[l-1]= '*';
179 for (i=0, *r=0; i<n; i++) snytprintfcat(r,l,"%s ",fn(i));
180 assert(!r[l-1] && r[l-2]==' ');
185 static const char *seei_group(int i) {
186 return calling_groups[i];
188 static const char *see_c_group(void) {
189 return see_c_list(request_mbuf.ngids,seei_group);
192 static const char *seei_gid(int i) {
193 static char buf[CHAR_BIT*sizeof(gid_t)/3+4];
195 snyprintf(buf,sizeof(buf),"%ld",(long)calling_gids[i]);
198 static const char *see_c_gid(void) {
199 return see_c_list(request_mbuf.ngids,seei_gid);
202 static const struct serv_envinfo {
204 const char *(*fn)(void);
206 { "USER", see_loginname },
207 { "LOGNAME", see_loginname },
208 { "HOME", see_home },
209 { "SHELL", see_shell },
210 { "PATH", defaultpath },
211 { "USERV_SERVICE", see_service },
212 { "USERV_CWD", see_c_cwd },
213 { "USERV_USER", see_c_loginname },
214 { "USERV_UID", see_c_uid },
215 { "USERV_GROUP", see_c_group },
216 { "USERV_GID", see_c_gid },
220 void execservice(const int synchsocket[], int clientfd) {
221 static const char *const setenvpfargs[]= {
224 ". " SETENVIRONMENTPATH "; exec \"$@\"",
228 int fd, realfd, holdfd, newfd, r, envvarbufsize=0, targ, nargs, i, l, fdflags;
231 const char **args, *const *cpp;
234 const struct serv_envinfo *sei;
236 if (dup2(fdarray[2].realfd,2)<0) {
237 static const char duperrmsg[]= "uservd(service): cannot dup2 for stderr\n";
238 unused= write(fdarray[2].realfd,duperrmsg,sizeof(duperrmsg)-1);
242 serv_resetsignal(SIGPIPE);
243 serv_resetsignal(SIGCHLD);
245 if (close(synchsocket[0])) serv_syscallfail("close parent synch socket");
247 if (setpgid(0,0)) serv_syscallfail("set process group");
249 r= write(synchsocket[1],&synchmsg,1);
250 if (r!=1) serv_syscallfail("write synch byte to parent");
251 r= synchread(synchsocket[1],'g');
252 if (r) serv_syscallfail("reach synch byte from parent");
253 if (close(synchsocket[1])) serv_syscallfail("close our synch socket");
255 if (close(clientfd)) serv_syscallfail("close client socket fd");
257 /* First we need to close the holding writing ends of the pipes
258 * inherited from our parent: */
259 for (fd=0; fd<fdarrayused; fd++) {
260 if (fdarray[fd].holdfd == -1) continue;
261 if (close(fdarray[fd].holdfd)) serv_syscallfail("close pipe hold fd");
262 fdarray[fd].holdfd= -1;
264 /* Now we can reuse the .holdfd member of the fdarray entries. */
266 /* We have to make all the fd's work. It's rather a complicated
267 * algorithm, unfortunately. We remember in holdfd[fd] whether fd
268 * is being used to hold a file descriptor we actually want for some
269 * other real fd in the service program; holdfd[fd] contains the fd
270 * we eventually want fd to be dup'd into, so that realfd[holdfd[fd]]==fd.
271 * After setting up the holdfds we go through the fds in order of
272 * eventual fd making sure that fd is the one we want it to be. If the
273 * holdfd tells us we're currently storing some other fd in there we
274 * move it out of the way with dup and record its new location.
276 for (fd=0; fd<fdarrayused; fd++) {
277 if (fdarray[fd].realfd < fdarrayused && fdarray[fd].realfd >= 0)
278 fdarray[fdarray[fd].realfd].holdfd= fd;
280 for (fd=0; fd<fdarrayused; fd++) {
281 realfd= fdarray[fd].realfd;
282 if (realfd == -1) continue;
283 holdfd= fdarray[fd].holdfd;
285 assert(realfd == fd);
286 fdarray[fd].holdfd= -1;
288 } else if (holdfd != -1) {
289 assert(fdarray[holdfd].realfd == fd);
290 newfd= dup(fd); if (newfd<0) serv_syscallfail("dup out of the way");
291 fdarray[holdfd].realfd= newfd;
292 if (newfd<fdarrayused) fdarray[newfd].holdfd= holdfd;
293 fdarray[fd].holdfd= -1;
295 if (dup2(fdarray[fd].realfd,fd)<0) serv_syscallfail("dup2 set up fd");
296 if (close(fdarray[fd].realfd)) serv_syscallfail("close old fd");
297 fdflags= fcntl(fd,F_GETFD); if (fdflags<0) serv_syscallfail("get fd flags");
298 if (fcntl(fd,F_SETFD,fdflags&~FD_CLOEXEC)==-1) serv_syscallfail("set no-close-on-exec on fd");
299 fdarray[fd].realfd= fd;
302 for (sei= serv_envinfos; sei->name; sei++)
303 if (setenv(sei->name,sei->fn(),1)) serv_syscallfail("setenv standard");
304 for (i=0; i<request_mbuf.nvars; i++) {
305 l= strlen(defvararray[i].key)+9;
306 if (l>envvarbufsize) { envvarbufsize= l; envvarbuf= xrealloc(envvarbuf,l); }
307 snyprintf(envvarbuf,l,"USERV_U_%s",defvararray[i].key);
308 if (setenv(envvarbuf,defvararray[i].value,1)) serv_syscallfail("setenv defvar");
312 if (setenvironment) for (cpp= setenvpfargs; *cpp; cpp++) nargs++;
314 if (execargs) for (pp= execargs; *pp; pp++) nargs++;
315 if (!suppressargs) nargs+= request_mbuf.nargs;
316 args= xmalloc(sizeof(char*)*(nargs+1));
318 if (setenvironment) for (cpp= setenvpfargs; *cpp; cpp++) args[targ++]= *cpp;
319 args[targ++]= execpath;
320 if (execargs) for (pp= execargs; *pp; pp++) args[targ++]= *pp;
321 if (!suppressargs) for (i=0; i<request_mbuf.nargs; i++) args[targ++]= argarray[i];
327 execv(args[0],(char* const*)args);
329 serv_syscallfail("exec service program");