* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
-#define RCSID "$Id: main.c,v 1.122 2003/02/24 12:46:37 fcusack Exp $"
+#define RCSID "$Id: main.c,v 1.123 2003/03/03 05:11:46 paulus Exp $"
#include <stdio.h>
#include <ctype.h>
struct notifier *phasechange = NULL;
struct notifier *exitnotify = NULL;
struct notifier *sigreceived = NULL;
+struct notifier *fork_notifier = NULL;
int hungup; /* terminal has been hung up */
int privileged; /* we're running as real uid root */
static int devfd; /* fd of underlying device */
static int fd_ppp = -1; /* fd for talking PPP */
static int fd_loop; /* fd for getting demand-dial packets */
+static int fd_devnull; /* fd for /dev/null */
int phase; /* where the link is at */
int kill_link;
/* Prototypes for procedures local to this file. */
static void setup_signals __P((void));
-static void create_pidfile __P((void));
-static void create_linkpidfile __P((void));
+static void create_pidfile __P((int pid));
+static void create_linkpidfile __P((int pid));
static void cleanup __P((void));
static void get_input __P((void));
static void calltimeout __P((void));
link_stats_valid = 0;
new_phase(PHASE_INITIALIZE);
- /*
- * Ensure that fds 0, 1, 2 are open, to /dev/null if nowhere else.
- * This way we can close 0, 1, 2 in detach() without clobbering
- * a fd that we are using.
- */
- if ((i = open("/dev/null", O_RDWR)) >= 0) {
- while (0 <= i && i <= 2)
- i = dup(i);
- if (i >= 0)
- close(i);
- }
-
script_env = NULL;
/* Initialize syslog facilities */
end_pr_log();
}
- /*
- * Early check for remote number authorization.
- */
- if (!auth_number()) {
- warn("calling number %q is not authorized", remote_number);
- exit(EXIT_CNID_AUTH_FAILED);
- }
-
if (dryrun)
die(0);
*/
sys_init();
+ /* Make sure fds 0, 1, 2 are open to somewhere. */
+ fd_devnull = open(_PATH_DEVNULL, O_RDWR);
+ if (fd_devnull < 0)
+ fatal("Couldn't open %s: %m", _PATH_DEVNULL);
+ while (fd_devnull <= 2) {
+ i = dup(fd_devnull);
+ if (i < 0)
+ fatal("Critical shortage of file descriptors: dup failed: %m");
+ fd_devnull = i;
+ }
+
#ifdef USE_TDB
pppdb = tdb_open(_PATH_PPPDB, 0, 0, O_RDWR|O_CREAT, 0644);
if (pppdb != NULL) {
waiting = 0;
- create_linkpidfile();
+ create_linkpidfile(getpid());
/*
* If we're doing dial-on-demand, set up the interface now.
slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
script_setenv("IFNAME", ifname, iskey);
if (iskey) {
- create_pidfile(); /* write pid to file */
- create_linkpidfile();
+ create_pidfile(getpid()); /* write pid to file */
+ create_linkpidfile(getpid());
}
}
{
int pid;
char numbuf[16];
+ int pipefd[2];
if (detached)
return;
+ if (pipe(pipefd) == -1)
+ pipefd[0] = pipefd[1] = -1;
if ((pid = fork()) < 0) {
error("Couldn't detach (fork failed: %m)");
die(1); /* or just return? */
if (pid != 0) {
/* parent */
notify(pidchange, pid);
+ /* update pid files if they have been written already */
+ if (pidfilename[0])
+ create_pidfile(pid);
+ if (linkpidfile[0])
+ create_linkpidfile(pid);
exit(0); /* parent dies */
}
setsid();
chdir("/");
- close(0);
- close(1);
- close(2);
+ dup2(fd_devnull, 0);
+ dup2(fd_devnull, 1);
+ dup2(fd_devnull, 2);
detached = 1;
if (log_default)
log_to_fd = -1;
- /* update pid files if they have been written already */
- if (pidfilename[0])
- create_pidfile();
- if (linkpidfile[0])
- create_linkpidfile();
slprintf(numbuf, sizeof(numbuf), "%d", getpid());
script_setenv("PPPD_PID", numbuf, 1);
+
+ /* wait for parent to finish updating pid & lock files and die */
+ close(pipefd[1]);
+ read(pipefd[0], numbuf, 1);
+ close(pipefd[0]);
}
/*
* Create a file containing our process ID.
*/
static void
-create_pidfile()
+create_pidfile(pid)
+ int pid;
{
FILE *pidfile;
}
static void
-create_linkpidfile()
+create_linkpidfile(pid)
+ int pid;
{
FILE *pidfile;
die(127);
}
+/*
+ * safe_fork - Create a child process. The child closes all the
+ * file descriptors that we don't want to leak to a script.
+ * The parent waits for the child to do this before returning.
+ */
+pid_t
+safe_fork()
+{
+ pid_t pid;
+ int pipefd[2];
+ char buf[1];
+
+ if (pipe(pipefd) == -1)
+ pipefd[0] = pipefd[1] = -1;
+ pid = fork();
+ if (pid < 0)
+ return -1;
+ if (pid > 0) {
+ close(pipefd[1]);
+ /* this read() blocks until the close(pipefd[1]) below */
+ read(pipefd[0], buf, 1);
+ close(pipefd[0]);
+ return pid;
+ }
+ sys_close();
+#ifdef USE_TDB
+ tdb_close(pppdb);
+#endif
+ notify(fork_notifier, 0);
+ close(pipefd[0]);
+ /* this close unblocks the read() call above in the parent */
+ close(pipefd[1]);
+ return 0;
+}
/*
* device_script - run a program to talk to the specified fds
int in, out;
int dont_wait;
{
- int pid, fd;
+ int pid;
int status = -1;
int errfd;
++conn_running;
- pid = fork();
+ pid = safe_fork();
if (pid < 0) {
--conn_running;
}
/* here we are executing in the child */
- /* make sure fds 0, 1, 2 are occupied */
- while ((fd = dup(in)) >= 0) {
- if (fd > 2) {
- close(fd);
- break;
- }
- }
/* dup in and out to fds > 2 */
{
close(0);
close(1);
close(2);
- sys_close();
if (the_channel->close)
(*the_channel->close)();
closelog();
+ close(fd_devnull);
/* dup the in, out, err fds to 0, 1, 2 */
dup2(in, 0);
return 0;
}
- pid = fork();
+ pid = safe_fork();
if (pid == -1) {
error("Failed to create child process for %s: %m", prog);
return -1;
}
- if (pid == 0) {
- int new_fd;
+ if (pid != 0) {
+ if (debug)
+ dbglog("Script %s started (pid %d)", prog, pid);
+ record_child(pid, prog, done, arg);
+ return pid;
+ }
- /* Leave the current location */
- (void) setsid(); /* No controlling tty. */
- (void) umask (S_IRWXG|S_IRWXO);
- (void) chdir ("/"); /* no current directory. */
- setuid(0); /* set real UID = root */
- setgid(getegid());
+ /* Leave the current location */
+ (void) setsid(); /* No controlling tty. */
+ (void) umask (S_IRWXG|S_IRWXO);
+ (void) chdir ("/"); /* no current directory. */
+ setuid(0); /* set real UID = root */
+ setgid(getegid());
- /* Ensure that nothing of our device environment is inherited. */
- sys_close();
- closelog();
- close (0);
- close (1);
- close (2);
- if (the_channel->close)
- (*the_channel->close)();
-
- /* Don't pass handles to the PPP device, even by accident. */
- new_fd = open (_PATH_DEVNULL, O_RDWR);
- if (new_fd >= 0) {
- if (new_fd != 0) {
- dup2 (new_fd, 0); /* stdin <- /dev/null */
- close (new_fd);
- }
- dup2 (0, 1); /* stdout -> /dev/null */
- dup2 (0, 2); /* stderr -> /dev/null */
- }
+ /* Ensure that nothing of our device environment is inherited. */
+ closelog();
+ if (the_channel->close)
+ (*the_channel->close)();
+
+ /* Don't pass handles to the PPP device, even by accident. */
+ dup2(fd_devnull, 0);
+ dup2(fd_devnull, 1);
+ dup2(fd_devnull, 2);
+ close(fd_devnull);
#ifdef BSD
- /* Force the priority back to zero if pppd is running higher. */
- if (setpriority (PRIO_PROCESS, 0, 0) < 0)
- warn("can't reset priority to 0: %m");
+ /* Force the priority back to zero if pppd is running higher. */
+ if (setpriority (PRIO_PROCESS, 0, 0) < 0)
+ warn("can't reset priority to 0: %m");
#endif
- /* SysV recommends a second fork at this point. */
+ /* SysV recommends a second fork at this point. */
- /* run the program */
- execve(prog, args, script_env);
- if (must_exist || errno != ENOENT) {
- /* have to reopen the log, there's nowhere else
- for the message to go. */
- reopen_log();
- syslog(LOG_ERR, "Can't execute %s: %m", prog);
- closelog();
- }
- _exit(-1);
+ /* run the program */
+ execve(prog, args, script_env);
+ if (must_exist || errno != ENOENT) {
+ /* have to reopen the log, there's nowhere else
+ for the message to go. */
+ reopen_log();
+ syslog(LOG_ERR, "Can't execute %s: %m", prog);
+ closelog();
}
-
- if (debug)
- dbglog("Script %s started (pid %d)", prog, pid);
- record_child(pid, prog, done, arg);
-
- return pid;
+ _exit(-1);
}
projects / ppp.git / blobdiff