first pass at ppp-watch

1 files changed, 420 insertions, 0 deletions

diff --git a/src/ppp-watch.c b/src/ppp-watch.c
new file mode 100644
index 00000000..2e3cd257
--- /dev/null
+++ b/src/ppp-watch.c
@@ -0,0 +1,420 @@
+/*
+ * ppp-watch.c
+ *
+ * Bring up a PPP connection and Do The Right Thing[tm] to make bringing
+ * the connection up or down with ifup and ifdown syncronous.  Takes
+ * one argument: the logical name of the device to bring up.  Does not
+ * detach until the interface is up or has permanently failed to come up.
+ *
+ * Copyright 1999 Red Hat, Inc.
+ *
+ * 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+/* Algorithm:
+ *   fork
+ *   if child:
+ *     Register with netreport.  (now exit implies deregister first)
+ *     fork/exec ifup-ppp daemon <interface>
+ *   else:
+ *     while (1):
+ *       sigsuspend()
+ *       if SIGTERM:
+ *         kill pppd pgrp
+ *         exit
+ *       if SIGHUP:
+ *         reload ifcfg files
+ *         kill pppd pgrp
+ *         wait for SIGCHLD to redial
+ *       if SIGIO:
+ *         if no physical device found: continue
+ *         elif physical device is down:
+ *           wait for pppd to exit to redial if appropriate
+ *         else: (physical device is up)
+ *           detach; continue
+ *       if SIGCHLD: (pppd exited)
+ *         wait()
+ *         if pppd exited:
+ *           if PERSIST: redial
+ *           else: exit
+ *         else: (pppd was killed)
+ *           exit
+ *
+ *
+ * When ppp-watch itself dies for reasons of its own, it uses a return code
+ * higher than 30 so as not to clash with pppd return codes, which, as of
+ * this writing, range from 0 to 19.
+ */
+
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/resource.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <net/if.h>
+
+#include "shvar.h"
+
+static int theSigterm = 0;
+static int theSighup = 0;
+static int theSigio = 0;
+static int theSigchld = 0;
+
+
+static void
+detach(int now, int parentExitCode) {
+    static int pipeArray[2];
+    char exitCode;
+
+    if (now) {
+	/* execute -- ignore errors in case called more than once */
+	exitCode = parentExitCode;
+	write(pipeArray[1], &exitCode, 1);
+	close(pipeArray[1]);
+
+    } else {
+	/* set up */
+	int child;
+
+	if (pipe(pipeArray)) exit (25);
+
+	child = fork();
+	if (child < 0) exit(26);
+	if (child) {
+	    /* parent process */
+	    close (pipeArray[1]);
+	    while (read (pipeArray[0], &exitCode, 1) < 0) {
+		switch (errno) {
+		    case EINTR: continue;
+		    default: exit (27); /* this will catch EIO in particular */
+		}
+	    }
+	    exit(exitCode);
+
+	} else {
+	    /* child process */
+	    close (pipeArray[0]);
+	    /* become a daemon */
+	    close (0);
+	    close (1);
+	    close (2);
+	}
+    }
+}
+
+
+static void
+doPidFile(char *device) {
+    static char *pidFileName = NULL;
+    char *pidFilePath;
+    int fd; FILE *f;
+
+    if (pidFileName) {
+	/* remove it */
+	pidFilePath = alloca(strlen(pidFileName) + 25);
+	sprintf(pidFilePath, "/var/run/pppwatch-%s.pid", pidFileName);
+	unlink(pidFilePath); /* not much we can do in case of error... */
+    }
+
+    if (device) {
+	/* create it */
+	pidFileName = device;
+	pidFilePath = alloca(strlen(pidFileName) + 25);
+	sprintf(pidFilePath, "/var/run/pppwatch-%s.pid", pidFileName);
+	fd = open(pidFilePath, O_WRONLY|O_TRUNC|O_CREAT,
+		  S_IRUSR|S_IWUSR | S_IRGRP | S_IROTH);
+	f = fdopen(fd, "r+");
+	fprintf(f, "%d\n", getpid());
+	fclose(f);
+    }
+}
+
+
+
+
+
+int
+fork_exec(int wait, char *path, char *arg1, char *arg2)
+{
+    pid_t child;
+    int status;
+
+    if (!(child = fork())) {
+	/* child */
+	execl(path, path, arg1, arg2, 0);
+	perror(path);
+	_exit (1);
+    }
+
+    if (wait) {
+	wait4 (child, &status, 0, NULL);
+	if (WIFEXITED(status) && (WEXITSTATUS(status) == 0)) {
+	    return 0;
+	} else {
+	    return 1;
+	}
+    } else {
+	return 0;
+    }
+}
+
+
+
+static void
+cleanExit(int exitCode) {
+    fork_exec(1, "/sbin/netreport", "-r", NULL);
+    detach(1, exitCode);
+    exit(exitCode);
+    doPidFile(NULL);
+}
+
+
+
+static void
+signal_handler (int signum) {
+    switch(signum) {
+    case SIGTERM:
+	theSigterm = 1; break;
+    case SIGHUP:
+	theSighup = 1; break;
+    case SIGIO:
+	theSigio = 1; break;
+    case SIGCHLD:
+	theSigchld = 1; break;
+    }
+}
+
+
+static shvarFile *
+shvarfilesGet(char *interfaceName) {
+    shvarFile *ifcfg;
+    char *ifcfgName, *ifcfgParentName, *ifcfgParentDiff;
+    static char ifcfgPrefix[] = "/etc/sysconfig/network-scripts/ifcfg-";
+
+    ifcfgName = alloca(sizeof(ifcfgPrefix)+strlen(interfaceName)+1);
+    sprintf(ifcfgName, "%s%s", ifcfgPrefix, interfaceName);
+    ifcfg = svNewFile(ifcfgName);
+    if (!ifcfg) return NULL;
+
+    /* Do we have a parent interface to inherit? */
+    ifcfgParentDiff = strchr(interfaceName, '-');
+    if (ifcfgParentDiff) {
+        /* allocate more than enough memory... */
+	ifcfgParentName = alloca(sizeof(ifcfgPrefix)+strlen(interfaceName)+1);
+	strcpy(ifcfgParentName, ifcfgPrefix);
+	strncat(ifcfgParentName, interfaceName, ifcfgParentDiff-interfaceName);
+	ifcfg->parent = svNewFile(ifcfgParentName);
+    }
+
+    return ifcfg;
+}
+
+
+
+static char *
+pppLogicalToPhysical(int *pppdPid, char *logicalName) {
+    char *mapFileName;
+    char buffer[20]; /* more than enough space for ppp<n> */
+    char *p, *q;
+    int f, n;
+    char *physicalDevice = NULL;
+
+    mapFileName = alloca (strlen(logicalName)+20);
+    sprintf(mapFileName, "/var/run/ppp-%s.pid", logicalName);
+    if ((f = open(mapFileName, O_RDONLY)) >= 0) {
+	n = read(f, buffer, 20);
+	if (n > 0) {
+	    buffer[n] = '\0';
+	    /* get past pid */
+	    p = buffer; while (*p && *p != '\n') p++; *p = '\0'; p++;
+	    if (pppdPid) *pppdPid = atoi(buffer);
+	    /* get rid of \n */
+	    q = p; while (*q && *q != '\n' && q < buffer+n) q++; *q = '\0';
+	    if (*p) physicalDevice = strdup(p);
+	}
+	close(f);
+    }
+
+    return physicalDevice;
+}
+
+
+static int
+interfaceStatus(char *device) {
+    int sock = 0;
+    int pfs[] = {AF_INET, AF_IPX, AF_AX25, AF_APPLETALK, 0};
+    int p = 0;
+    struct ifreq ifr;
+    int retcode = 0;
+
+    while (!sock && pfs[p]) {
+        sock = socket(pfs[p++], SOCK_DGRAM, 0);
+    }
+    if (!sock) return 0;
+
+    memset(&ifr, 0, sizeof(ifr));
+    strcpy(ifr.ifr_name, device);
+
+    if (ioctl(sock, SIOCGIFFLAGS, &ifr) < 0) {
+        retcode = 0;
+    } else if (ifr.ifr_flags & IFF_UP) {
+        retcode = 1;
+    }
+
+    close(sock);
+    return retcode;
+}
+
+
+
+
+
+
+
+
+
+
+int
+main(int argc, char **argv) {
+    int status, waited;
+    char *device, *logicalDevice;
+    shvarFile *ifcfg;
+    sigset_t sigs;
+    int pppdPid;
+    int timeout = 30;
+    char *temp;
+    struct timeval tv;
+
+    if (argc != 2) {
+	fprintf (stderr, "usage: ppp-watch [ifcfg-]<logical-name>");
+	exit(30);
+    }
+
+    detach(0, 0); /* prepare */
+
+    signal(SIGTERM, signal_handler);
+    signal(SIGHUP, signal_handler);
+    signal(SIGIO, signal_handler);
+    signal(SIGCHLD, signal_handler);
+
+    sigemptyset(&sigs);
+    sigaddset(&sigs, SIGTERM);
+    sigaddset(&sigs, SIGHUP);
+    sigaddset(&sigs, SIGIO);
+    sigaddset(&sigs, SIGCHLD);
+    sigprocmask(SIG_BLOCK, &sigs, NULL);
+
+    sigfillset(&sigs);
+    sigdelset(&sigs, SIGTERM);
+    sigdelset(&sigs, SIGHUP);
+    sigdelset(&sigs, SIGIO);
+    sigdelset(&sigs, SIGCHLD);
+
+    doPidFile(device);
+
+    fork_exec(1, "/sbin/netreport", NULL, NULL);
+
+    if (!strncmp(argv[1], "ifcfg-", 6)) {
+	device = argv[1] + 6;
+    } else {
+	device = argv[1];
+    }
+    ifcfg = shvarfilesGet(device);
+    if (!ifcfg) cleanExit(28);
+
+    fork_exec(0, "/etc/sysconfig/network-scripts/ifup-ppp", "daemon", device);
+    temp = svGetValue(ifcfg, "RETRYTIMEOUT");
+    if (temp) {
+	timeout = atoi(temp);
+	free(temp);
+    } else {
+	timeout = 30;
+    }
+
+    while (1) {
+	sigsuspend(&sigs);
+	if (theSigterm) {
+	    theSigterm = 0;
+	    if (logicalDevice) free(logicalDevice);
+	    logicalDevice = pppLogicalToPhysical(&pppdPid, device);
+	    if (logicalDevice) free(logicalDevice);
+	    kill(-pppdPid, SIGTERM);
+	    cleanExit(0);
+	}
+	if (theSighup) {
+	    theSighup = 0;
+	    if (ifcfg->parent) svCloseFile(ifcfg->parent);
+	    svCloseFile(ifcfg);
+	    ifcfg = shvarfilesGet(device);
+	    logicalDevice = pppLogicalToPhysical(&pppdPid, device);
+	    if (logicalDevice) free(logicalDevice);
+	    kill(-pppdPid, SIGTERM);
+	    /* redial when SIGCHLD arrives */
+	    timeout = 1; /* give things time to stabilize... */
+	}
+	if (theSigio) {
+	    theSigio = 0;
+	    if (logicalDevice) {
+		free(logicalDevice);
+		temp = svGetValue(ifcfg, "DISCONNECTTIMEOUT");
+		if (temp) {
+		    timeout = atoi(temp);
+		    free(temp);
+		} else {
+		    timeout = 30;
+		}
+	    }
+	    logicalDevice = pppLogicalToPhysical(NULL, device);
+	    if (logicalDevice) {
+		if (interfaceStatus(device)) {
+		    /* device is up */
+		    detach(1, 0);
+		}
+	    }
+	}
+	if (theSigchld) {
+	    theSigchld = 0;
+	    waited = wait3(&status, 0, NULL);
+	    if (waited < 0) continue;
+
+	    if (!WIFEXITED(status)) cleanExit(29);
+
+	    if (svTrueValue(ifcfg, "PERSIST", 0)) {
+		fork_exec(0, "/etc/sysconfig/network-scripts/ifup-ppp", "daemon", device);
+		temp = svGetValue(ifcfg, "RETRYTIMEOUT");
+		if (temp) {
+		    timeout = atoi(temp);
+		    free(temp);
+		} else {
+		    timeout = 30;
+		}
+		tv.tv_sec = timeout;
+		select(0, NULL, NULL, NULL, &tv);
+	    } else {
+		cleanExit(0);
+	    }
+	}
+    }
+}