--- /dev/null
+/*
+ * userv - execserv.c
+ * daemon code which executes actual service (ie child process)
+ *
+ * Copyright (C)1996-1997 Ian Jackson
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with userv; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <limits.h>
+#include <errno.h>
+#include <assert.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <signal.h>
+
+#include "config.h"
+#include "common.h"
+#include "daemon.h"
+#include "lib.h"
+
+static void NONRETURNING serv_syscallfail(const char *msg) {
+ fputs("uservd(service): ",stderr);
+ perror(msg);
+ _exit(-1);
+}
+
+static void serv_resetsignal(int signo) {
+ struct sigaction sig;
+
+ sig.sa_handler= SIG_DFL;
+ sigemptyset(&sig.sa_mask);
+ sig.sa_flags= 0;
+ if (sigaction(signo,&sig,0)) serv_syscallfail("reset signal handler");
+}
+
+static const char *see_logname(void) { return serviceuser; }
+static const char *see_home(void) { return serviceuser_dir; }
+static const char *see_shell(void) { return serviceuser_shell; }
+
+static const char *see_path(void) {
+ return serviceuser_uid ? DEFAULTPATH_USER : DEFAULTPATH_ROOT;
+}
+
+static const char *see_service(void) { return service; }
+static const char *see_c_cwd(void) { return cwd; }
+static const char *see_c_logname(void) { return logname; }
+static const char *see_c_uid(void) {
+ static char buf[CHAR_BIT*sizeof(uid_t)/3+4];
+ snyprintf(buf,sizeof(buf),"%lu",(unsigned long)request_mbuf.callinguid);
+ return buf;
+}
+
+static const char *see_c_list(int n, const char *(*fn)(int i)) {
+ int l, i;
+ char *r;
+
+ for (i=0, l=1; i<n; i++) l+= strlen(fn(i))+1;
+ r= xmalloc(l); r[l-1]= '*';
+ for (i=0, *r=0; i<n; i++) snytprintfcat(r,l,"%s ",fn(i));
+ assert(!r[l-1] && r[l-2]==' ');
+ r[l-2]= 0;
+ return r;
+}
+
+static const char *seei_group(int i) {
+ return calling_groups[i];
+}
+static const char *see_c_group(void) {
+ return see_c_list(request_mbuf.ngids,seei_group);
+}
+
+static const char *seei_gid(int i) {
+ static char buf[CHAR_BIT*sizeof(gid_t)/3+4];
+
+ snyprintf(buf,sizeof(buf),"%d",calling_gids[i]);
+ return buf;
+}
+static const char *see_c_gid(void) {
+ return see_c_list(request_mbuf.ngids,seei_gid);
+}
+
+static const struct serv_envinfo {
+ const char *name;
+ const char *(*fn)(void);
+} serv_envinfos[]= {
+ { "USER", see_logname },
+ { "LOGNAME", see_logname },
+ { "HOME", see_home },
+ { "SHELL", see_shell },
+ { "PATH", see_path },
+ { "USERV_SERVICE", see_service },
+ { "USERV_CWD", see_c_cwd },
+ { "USERV_USER", see_c_logname },
+ { "USERV_UID", see_c_uid },
+ { "USERV_GROUP", see_c_group },
+ { "USERV_GID", see_c_gid },
+ { 0 }
+};
+
+void execservice(const int synchsocket[], int clientfd) {
+ static const char *const setenvpfargs[]= {
+ "/bin/sh",
+ "-c",
+ ". " SETENVIRONMENTPATH "; exec \"$@\"",
+ "-",
+ 0
+ };
+ int fd, realfd, holdfd, newfd, r, envvarbufsize=0, targ, nargs, i, l;
+ char *envvarbuf=0;
+ const char **args, *const *cpp;
+ char *const *pp;
+ char synchmsg;
+ const struct serv_envinfo *sei;
+
+ if (dup2(fdarray[2].realfd,2)<0) {
+ static const char duperrmsg[]= "uservd(service): cannot dup2 for stderr\n";
+ write(fdarray[2].realfd,duperrmsg,sizeof(duperrmsg)-1);
+ _exit(-1);
+ }
+ serv_resetsignal(SIGPIPE);
+ serv_resetsignal(SIGCHLD);
+
+ if (close(synchsocket[0])) serv_syscallfail("close parent synch socket");
+
+ if (setpgid(0,0)) serv_syscallfail("set process group");
+ synchmsg= 'y';
+ r= write(synchsocket[1],&synchmsg,1);
+ if (r!=1) serv_syscallfail("write synch byte to parent");
+ r= synchread(synchsocket[1],'g');
+ if (r) serv_syscallfail("reach synch byte from parent");
+
+ if (close(clientfd)) serv_syscallfail("close client socket fd");
+
+ /* Now we have to make all the fd's work. It's rather a complicated
+ * algorithm, unfortunately. We remember in holdfd[fd] whether fd
+ * is being used to hold a file descriptor we actually want for some
+ * other real fd in the service program; holdfd[fd] contains the fd
+ * we eventually want fd to be dup'd into, so that realfd[holdfd[fd]]==fd.
+ * After setting up the holdfds we go through the fds in order of
+ * eventual fd making sure that fd is the one we want it to be. If the
+ * holdfd tells us we're currently storing some other fd in there we
+ * move it out of the way with dup and record its new location.
+ */
+ for (fd=0; fd<fdarrayused; fd++) {
+ if (fdarray[fd].holdfd == -1) continue;
+ if (close(fdarray[fd].holdfd)) serv_syscallfail("close pipe hold fd");
+ fdarray[fd].holdfd= -1;
+ }
+ for (fd=0; fd<fdarrayused; fd++) {
+ if (fdarray[fd].realfd < fdarrayused) fdarray[fdarray[fd].realfd].holdfd= fd;
+ }
+ for (fd=0; fd<fdarrayused; fd++) {
+ realfd= fdarray[fd].realfd;
+ if (realfd == -1) continue;
+ holdfd= fdarray[fd].holdfd;
+ if (holdfd == fd) {
+ assert(realfd == fd);
+ fdarray[fd].holdfd= -1;
+ continue;
+ } else if (holdfd != -1) {
+ assert(fdarray[holdfd].realfd == fd);
+ newfd= dup(fd); if (newfd<0) serv_syscallfail("dup out of the way");
+ fdarray[holdfd].realfd= newfd;
+ if (newfd<fdarrayused) fdarray[newfd].holdfd= holdfd;
+ fdarray[fd].holdfd= -1;
+ }
+ if (dup2(fdarray[fd].realfd,fd)<0) serv_syscallfail("dup2 set up fd");
+ if (close(fdarray[fd].realfd)) serv_syscallfail("close old fd");
+ if (fcntl(fd,F_SETFD,0)<0) serv_syscallfail("set no-close-on-exec on fd");
+ fdarray[fd].realfd= fd;
+ }
+
+ for (sei= serv_envinfos; sei->name; sei++)
+ if (setenv(sei->name,sei->fn(),1)) serv_syscallfail("setenv standard");
+ for (i=0; i<request_mbuf.nvars; i++) {
+ l= strlen(defvararray[i][0])+9;
+ if (l>envvarbufsize) { envvarbufsize= l; envvarbuf= xrealloc(envvarbuf,l); }
+ snyprintf(envvarbuf,l,"USERV_U_%s",defvararray[i][0]);
+ if (setenv(envvarbuf,defvararray[i][1],1)) serv_syscallfail("setenv defvar");
+ }
+
+ nargs= 0;
+ if (setenvironment) for (cpp= setenvpfargs; *cpp; cpp++) nargs++;
+ nargs++;
+ if (execargs) for (pp= execargs; *pp; pp++) nargs++;
+ if (!suppressargs) nargs+= request_mbuf.nargs;
+ args= xmalloc(sizeof(char*)*(nargs+1));
+ targ= 0;
+ if (setenvironment) for (cpp= setenvpfargs; *cpp; cpp++) args[targ++]= *cpp;
+ args[targ++]= execpath;
+ if (execargs) for (pp= execargs; *pp; pp++) args[targ++]= *pp;
+ if (!suppressargs) for (i=0; i<request_mbuf.nargs; i++) args[targ++]= argarray[i];
+ args[targ]= 0;
+
+ execv(args[0],(char* const*)args);
+
+ serv_syscallfail("exec service program");
+ _exit(-1);
+}
~ian / userv.git / blobdiff