commit 6af08f4bf508391dd4f75a241824047e3e3bb4e6
parent b8b26c5aa46c929fd4b0d785ace5ad1b92526c85
Author: leitner <leitner>
Date: Sat, 11 Apr 2015 07:23:31 +0000
add waitinterface and waitport
Diffstat:
5 files changed, 255 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,5 +1,5 @@
all: minit msvc pidfilehack hard-reboot write_proc killall5 shutdown \
-minit-update serdo ftrigger
+minit-update serdo ftrigger waitinterface waitport # governor
#CFLAGS=-pipe -march=i386 -fomit-frame-pointer -Os -I../dietlibc/include
CC=gcc
@@ -51,6 +51,9 @@ msvc: msvc.o
ftrigger: ftrigger.o
minit-update: minit-update.o split.o openreadclose.o
serdo: serdo.o
+waitinterface: waitinterface.o
+waitport: waitport.o
+governor: governor.o
shutdown: shutdown.o split.o openreadclose.o opendevconsole.o
$(DIET) $(CROSS)$(CC) $(LDFLAGS) -o shutdown $^
@@ -63,7 +66,7 @@ shutdown: shutdown.o split.o openreadclose.o opendevconsole.o
clean:
rm -f *.o minit msvc pidfilehack hard-reboot write_proc killall5 \
- shutdown minit-update serdo ftrigger
+ shutdown minit-update serdo ftrigger waitinterface waitport governor
test: test.c
gcc -nostdlib -o $@ $^ -I../dietlibc/include ../dietlibc/start.o ../dietlibc/dietlibc.a
@@ -84,7 +87,7 @@ install-files:
install -d $(DESTDIR)$(MINITROOT) $(DESTDIR)/sbin $(DESTDIR)/bin $(DESTDIR)$(MANDIR)/man8
install minit pidfilehack $(DESTDIR)/sbin
install write_proc hard-reboot minit-update $(DESTDIR)/sbin
- install msvc serdo $(DESTDIR)/bin
+ install msvc serdo ftrigger waitinterface waitport $(DESTDIR)/bin
if test -f $(DESTDIR)/sbin/shutdown; then install shutdown $(DESTDIR)/sbin/mshutdown; else install shutdown $(DESTDIR)/sbin/shutdown; fi
test -f $(DESTDIR)/sbin/init || ln $(DESTDIR)/sbin/minit $(DESTDIR)/sbin/init
install -m 644 hard-reboot.8 minit-list.8 minit-shutdown.8 minit-update.8 minit.8 msvc.8 pidfilehack.8 serdo.8 $(DESTDIR)$(MANDIR)/man8
diff --git a/waitinterface.1 b/waitinterface.1
@@ -0,0 +1,30 @@
+.TH waitinterface 1
+.SH NAME
+waitinterface \- wait for a network interface to show up
+.SH SYNOPSIS
+.B waitinterface ifname command ...
+
+.B waitinterfaceup ifname command ...
+.SH DESCRIPTION
+.B waitinterface
+will wait for /sys/class/net/ifname to show up (it will try for a few
+seconds, then abort and fail if nothing shows up).
+
+If it is called under the name waitinterfaceup (make a symbolic or hard
+link at installation!), it will also wait for the interface to go up. If
+that does not happen within a few seconds, it will abort and fail.
+
+If execution gets this far, the rest of the command line is run (using
+execve, so you have to pass in the full path to the command).
+
+This program is meant for use when one command loads a network driver
+into the kernel, and the next program wants to initialize it. There is a
+race condition between the kernel module creating the network interface
+and the initialization functions attempting to initialize that
+interface. In this case you can use waitinterface to delay the
+initialization until the interface is actually there.
+
+.SH AUTHOR
+waitinterface was written by Felix von Leitner and can be downloaded from
+.I http://www.fefe.de/minit/
+
diff --git a/waitinterface.c b/waitinterface.c
@@ -0,0 +1,49 @@
+#include <unistd.h>
+#include <errmsg.h>
+#include <time.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <fmt.h>
+#include <netinet/in.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+
+int main(int argc,char* argv[],char* envp[]) {
+ unsigned int i;
+ struct timespec req,rem;
+ struct stat ss;
+ char* sys;
+ int found;
+ errmsg_iam("waitinterface");
+ if (argc<2)
+ die(0,"usage: waitinterface wlan0 /usr/sbin/dhcpcd wlan0\n\twaits for wlan0 to show up and then executes the rest of the command line");
+ sys=fmt_strm_alloca("/sys/class/net/",argv[1]);
+ req.tv_sec=0; req.tv_nsec=100000000;
+ for (i=0; i<100; ++i) {
+ if ((found=lstat(sys,&ss))==0) break;
+ nanosleep(&req,&rem);
+ }
+ if (found==-1)
+ die(1,"interface not showing up");
+ if (strstr(argv[0],"up")) {
+ /* they want the interface to be up, too */
+ int s=socket(PF_INET6,SOCK_DGRAM,IPPROTO_IP);
+ struct ifreq ifr;
+ if (s==-1) s=socket(PF_INET,SOCK_DGRAM,IPPROTO_IP);
+ if (s==-1) diesys(1,"socket");
+ strncpy(ifr.ifr_name,argv[1],sizeof(ifr.ifr_name));
+ for (i=0; i<100; ++i) {
+ if (ioctl(s,SIOCGIFFLAGS,&ifr)==0 && (ifr.ifr_flags&IFF_UP)) break;
+ nanosleep(&req,&rem);
+ }
+ close(s);
+ if (!(ifr.ifr_flags&IFF_UP))
+ die(1,"interface not up");
+ }
+ if (argv[2]) {
+ execve(argv[2],argv+2,envp);
+ diesys(1,"execve");
+ }
+ return 0;
+}
diff --git a/waitport.1 b/waitport.1
@@ -0,0 +1,27 @@
+.TH waitport 1
+.SH NAME
+waitport \- wait for a local TCP service to show up
+.SH SYNOPSIS
+.B waitport port command ...
+
+.B waitport ip/port command ...
+
+.SH DESCRIPTION
+.B waitport
+will repeatedly do what netstat does (go through /proc/net/tcp and
+/proc/net/tcp6) and look for a specific TCP port in LISTEN state to show
+up. When that happens, it will run the rest of the command line.
+
+There is a timeout after 1000 tries (10 tries per second). If the port
+does not show up by then, waitport will abort with a non-zero exit code.
+
+This program is meant for use with minit, when one service starts a
+service, and another program should only be started once the first
+service has bound to the port (i.e. is accepting connections).
+
+Use waitport to resolve race conditions in dependency chains in minit.
+
+.SH AUTHOR
+waitinterface was written by Felix von Leitner and can be downloaded from
+.I http://www.fefe.de/minit/
+
diff --git a/waitport.c b/waitport.c
@@ -0,0 +1,143 @@
+#include <unistd.h>
+#include <errmsg.h>
+#include <time.h>
+#include <string.h>
+#include <fmt.h>
+#include <scan.h>
+#include <ip4.h>
+#include <ip6.h>
+#include <stralloc.h>
+#include <buffer.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+static int netstat(const char* addr,unsigned int wantedport) {
+ /* see linux/Documentation/networking/proc_net_tcp.txt */
+ int fd=-1;
+ char rbuf[4096]; /* since these files can become arbitrarily large, we'll use a real buffer to read from them */
+ const char* filenames[] = { "/proc/net/tcp6", "/proc/net/tcp" };
+ buffer b;
+ unsigned int fn;
+ stralloc line;
+
+ for (fn=0; fn<sizeof(filenames)/sizeof(filenames[0]); ++fn) {
+ const char* filename=filenames[fn];
+
+ fd=open(filename,O_RDONLY|O_CLOEXEC);
+ if (fd==-1)
+ continue;
+ buffer_init(&b,read,fd,rbuf,sizeof(rbuf)); /* can't fail */
+ for (;;) {
+ int r;
+ char* c;
+ char* local;
+ int v6;
+ stralloc_zero(&line);
+ if ((r=buffer_getline_sa(&b,&line))==-1) {
+ close(fd);
+ die(1,"read error from ",filename);
+ }
+ if (r==0) break;
+ if (line.len < 1 || line.s[line.len-1]!='\n') {
+parseerror:
+ close(fd);
+ die(1,"parse error in ",filename);
+ }
+ line.s[line.len-1]=0; /* string is now null terminated */
+
+ /* First token is something like "917:", skip */
+ for (c=line.s; *c && *c!=':'; ++c) ;
+ if (*c != ':') continue; /* first line is boilerplate text and has no :-token, skip it */
+ ++c;
+ for (; *c==' '; ++c) ;
+ /* Next token is something like "00000000:1770" or "00000000000000000000000000000000:0016" */
+ local=c;
+ for (; isxdigit(*c); ++c) ;
+ if (c-local != 8 && c-local != 32) /* we only support ipv4 and ipv6; this is neither */
+ continue;
+ v6=(c-local==32);
+ if (*c!=':') goto parseerror;
+ for (r=1; r<5; ++r) {
+ if (!isxdigit(c[r])) goto parseerror;
+ }
+ if (c[5]!=' ') goto parseerror;
+ c[5]=0;
+ c+=6;
+ /* Next token is the same thing, but we don't really need it, so
+ * just skip till next whitespace */
+ for (; *c && *c!=' '; ++c) ;
+ if (*c!=' ') goto parseerror; ++c;
+ /* Next is the state; if we are looking at tcp, 0A means LISTEN */
+ if (filename[10]=='t' && c[0]=='0' && c[1]=='A') {
+ /* TCP LISTEN */
+ size_t n;
+ union {
+ char ip[16];
+ uint32_t ints[4];
+ } omgwtfbbq;
+ char ipstring[FMT_IP6];
+ unsigned short port;
+ unsigned long temp;
+
+ /* we can only be here if the hex string is 8 or 32 bytes long, see above */
+ for (n=0; n<(unsigned int)v6*3+1; ++n) {
+ scan_xlongn(local+n*8,8,&temp);
+ omgwtfbbq.ints[n]=temp;
+ }
+
+ if (scan_xshort(local+(((unsigned int)v6*3+1)*8)+1,&port)!=4) /* can't happen, we validated with isxdigit */
+ goto parseerror;
+
+ ipstring[v6 ? fmt_ip6c(ipstring,omgwtfbbq.ip) : fmt_ip4(ipstring,omgwtfbbq.ip)]=0;
+
+ if (!strcmp(ipstring,addr?addr : (v6?"::":"0.0.0.0")) && port==wantedport) {
+ close(fd);
+ return 1;
+ }
+
+ }
+ }
+ close(fd);
+ fd=-1;
+ }
+
+ return 0;
+}
+
+int main(int argc,char* argv[],char* envp[]) {
+ unsigned short port;
+
+ unsigned int i;
+ struct timespec req,rem;
+
+ char* s=argv[1];
+ char* t=strchr(s,'/');
+
+ errmsg_iam("waitport");
+ if (argc<2)
+usage:
+ die(0,"usage: waitport ::/111 some.rpcd\n\twaits for a service to bind to TCP port 111 on ::, then executes the rest of the command line");
+
+ {
+ if (t) {
+ *t=0;
+ if (scan_ushort(t+1,&port)==0) goto usage;
+ } else {
+ if (scan_ushort(s,&port)==0) goto usage;
+ s=0;
+ }
+ }
+
+ req.tv_sec=0; req.tv_nsec=100000000;
+ for (i=0; i<1000; ++i) {
+ if (netstat(s,port)) {
+ if (argv[2]) {
+ execve(argv[2],argv+2,envp);
+ diesys(1,"execve");
+ }
+ return 0;
+ }
+ nanosleep(&req,&rem);
+ }
+ die(1,"service on port not showing up");
+}
