CONTRIB: debug: add new program "poll" to test poll() events
This simple program prepares a TCP connection between two ends and
allows to perform various operations on them such as send, recv, poll,
shutdown, close, reset, etc. It takes care of remaining particularly
silent to help inspection via strace, though it can also be verbose
and report status, errno, and poll events. It delays acceptation of
the incoming server-side connection so that it's even possible to
test the poll status on a listener with a pending connection, or
to close the connection without accepting it and inspect the effect
on the client.
Actions are executed in the command line order as they are parsed,
they may be grouped using commas when they are performed on the same
socket.
Example showing a successful recv() of pending data before a pending error:
$ ./poll -v -l pol,acc,pol -c snd,shw -s pol,rcv,pol,rcv,pol,snd,lin,clo -c pol,rcv,pol,rcv,pol
#### BEGIN ####
cmd #1 stp #1: do_pol(3): ret=1 ev=0x1 (IN)
cmd #1 stp #2: do_acc(3): ret=5
cmd #1 stp #3: do_pol(3): ret=0 ev=0
cmd #2 stp #1: do_snd(4): ret=3
cmd #2 stp #2: do_shw(4): ret=0
cmd #3 stp #1: do_pol(5): ret=1 ev=0x2005 (IN OUT RDHUP)
cmd #3 stp #2: do_rcv(5): ret=3
cmd #3 stp #3: do_pol(5): ret=1 ev=0x2005 (IN OUT RDHUP)
cmd #3 stp #4: do_rcv(5): ret=0
cmd #3 stp #5: do_pol(5): ret=1 ev=0x2005 (IN OUT RDHUP)
cmd #3 stp #6: do_snd(5): ret=3
cmd #3 stp #7: do_lin(5): ret=0
cmd #3 stp #8: do_clo(5): ret=0
cmd #4 stp #1: do_pol(4): ret=1 ev=0x201d (IN OUT ERR HUP RDHUP)
cmd #4 stp #2: do_rcv(4): ret=3
cmd #4 stp #3: do_pol(4): ret=1 ev=0x201d (IN OUT ERR HUP RDHUP)
cmd #4 stp #4: do_rcv(4): ret=-1 (Connection reset by peer)
cmd #4 stp #5: do_pol(4): ret=1 ev=0x2015 (IN OUT HUP RDHUP)
#### END ####
diff --git a/contrib/debug/Makefile b/contrib/debug/Makefile
index 74e7547..385e0d1 100644
--- a/contrib/debug/Makefile
+++ b/contrib/debug/Makefile
@@ -3,10 +3,15 @@
CC = gcc
OPTIMIZE = -O2
DEFINE =
-OBJS = flags
+OBJS = flags poll
+
+all: $(OBJS)
flags: flags.c
$(CC) $(OPTIMIZE) $(DEFINE) $(INCLUDE) -o $@ $^
+poll: poll.c
+ $(CC) $(OPTIMIZE) $(DEFINE) $(INCLUDE) -o $@ $^
+
clean:
rm -f $(OBJS) *.[oas] *~
diff --git a/contrib/debug/poll.c b/contrib/debug/poll.c
new file mode 100644
index 0000000..b535c07
--- /dev/null
+++ b/contrib/debug/poll.c
@@ -0,0 +1,358 @@
+#define _GNU_SOURCE // for POLLRDHUP
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* for OSes which don't have it */
+#ifndef POLLRDHUP
+#define POLLRDHUP 0
+#endif
+
+int verbose = 0;
+int cmd = 0;
+int cmdstep = 0;
+int zero = 0;
+int one = 1;
+int lfd = -1;
+int cfd = -1;
+int sfd = -1;
+struct sockaddr_in saddr, caddr;
+socklen_t salen, calen;
+
+void usage(const char *arg0)
+{
+ printf("Usage: %s [ arg [<action>[,...]] ] ...\n"
+ "args:\n"
+ " -h display this help\n"
+ " -v verbose mode (shows ret values)\n"
+ " -c <actions> perform <action> on client side socket\n"
+ " -s <actions> perform <action> on server side socket\n"
+ " -l <actions> perform <action> on listening socket\n"
+ "\n"
+ "actions for -c/-s/-l (multiple may be delimited by commas) :\n"
+ " acc accept on listener, implicit before first -s\n"
+ " snd send a few bytes of data\n"
+ " mor send a few bytes of data with MSG_MORE\n"
+ " rcv receive a few bytes of data\n"
+ " drn drain: receive till zero\n"
+ " shr SHUT_RD : shutdown read side\n"
+ " shw SHUT_WR : shutdown write side\n"
+ " shb SHUT_RDWR : shutdown both sides\n"
+ " lin disable lingering on the socket\n"
+ " clo close the file descriptor\n"
+ " pol poll() for any event\n"
+ "\n", arg0);
+}
+
+void die(const char *msg)
+{
+ if (msg)
+ fprintf(stderr, "%s\n", msg);
+ exit(1);
+}
+
+const char *get_errno(int ret)
+{
+ static char errmsg[100];
+
+ if (ret >= 0)
+ return "";
+
+ snprintf(errmsg, sizeof(errmsg), " (%s)", strerror(errno));
+ return errmsg;
+}
+
+void do_acc(int fd)
+{
+ int ret;
+
+ calen = sizeof(caddr);
+ ret = accept(lfd, (struct sockaddr*)&caddr, &calen);
+ if (sfd < 0)
+ sfd = ret;
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_snd(int fd)
+{
+ int ret;
+
+ ret = send(fd, "foo", 3, MSG_NOSIGNAL|MSG_DONTWAIT);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_mor(int fd)
+{
+ int ret;
+
+ ret = send(fd, "foo", 3, MSG_NOSIGNAL|MSG_DONTWAIT|MSG_MORE);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_rcv(int fd)
+{
+ char buf[10];
+ int ret;
+
+ ret = recv(fd, buf, sizeof(buf), MSG_DONTWAIT);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_drn(int fd)
+{
+ char buf[16384];
+ int total = -1;
+ int ret;
+
+ while (1) {
+ ret = recv(fd, buf, sizeof(buf), 0);
+ if (ret <= 0)
+ break;
+ if (total < 0)
+ total = 0;
+ total += ret;
+ }
+
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, total, get_errno(ret));
+}
+
+void do_shr(int fd)
+{
+ int ret;
+
+ ret = shutdown(fd, SHUT_RD);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_shw(int fd)
+{
+ int ret;
+
+ ret = shutdown(fd, SHUT_WR);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_shb(int fd)
+{
+ int ret;
+
+ ret = shutdown(fd, SHUT_RDWR);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_lin(int fd)
+{
+ struct linger nolinger = { .l_onoff = 1, .l_linger = 0 };
+ int ret;
+
+ ret = setsockopt(fd, SOL_SOCKET, SO_LINGER, &nolinger, sizeof(nolinger));
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_clo(int fd)
+{
+ int ret;
+
+ ret = close(fd);
+ if (verbose)
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s\n", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret));
+}
+
+void do_pol(int fd)
+{
+ struct pollfd fds = { .fd = fd, .events = POLLIN|POLLOUT|POLLRDHUP, .revents=0 };
+ int ret;
+
+ ret = poll(&fds, 1, 0);
+ if (verbose) {
+ printf("cmd #%d stp #%d: %s(%d): ret=%d%s ev=%#x ", cmd, cmdstep, __FUNCTION__, fd, ret, get_errno(ret), ret > 0 ? fds.revents : 0);
+ if (ret > 0 && fds.revents) {
+ int flags, flag;
+ putchar('(');
+
+ for (flags = fds.revents; flags; flags ^= flag) {
+ flag = flags ^ (flags & (flags - 1)); // keep lowest bit only
+ switch (flag) {
+ case POLLIN: printf("IN"); break;
+ case POLLOUT: printf("OUT"); break;
+ case POLLPRI: printf("PRI"); break;
+ case POLLHUP: printf("HUP"); break;
+ case POLLERR: printf("ERR"); break;
+ case POLLNVAL: printf("NVAL"); break;
+#if POLLRDHUP
+ case POLLRDHUP: printf("RDHUP"); break;
+#endif
+ default: printf("???[%#x]", flag); break;
+ }
+ if (flags ^ flag)
+ putchar(' ');
+ }
+ putchar(')');
+ }
+ putchar('\n');
+ }
+}
+
+int main(int argc, char **argv)
+{
+ const char *arg0;
+ char *word, *next;
+ int fd;
+
+ /* listener */
+ lfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+ if (lfd < 0)
+ die("socket(l)");
+
+ setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+
+ memset(&saddr, 0, sizeof(saddr));
+ saddr.sin_family = AF_INET;
+ saddr.sin_port = htons(0);
+ salen = sizeof(saddr);
+
+ if (bind(lfd, (struct sockaddr *)&saddr, salen) < 0)
+ die("bind()");
+
+ if (listen(lfd, 1000) < 0)
+ die("listen()");
+
+ if (getsockname(lfd, (struct sockaddr *)&saddr, &salen) < 0)
+ die("getsockname()");
+
+
+ /* client */
+ cfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+ if (cfd < 0)
+ die("socket(c)");
+
+ if (connect(cfd, (const struct sockaddr*)&saddr, salen) == -1)
+ die("connect()");
+
+ /* connection is pending in accept queue, accept() will either be
+ * explicit with "-l acc" below, or implicit on "-s <cmd>"
+ */
+
+ arg0 = argv[0];
+ if (argc < 2) {
+ usage(arg0);
+ exit(1);
+ }
+
+ write(1, "#### BEGIN ####\n", 16); // add a visible delimiter in the traces
+
+ while (argc > 1) {
+ argc--; argv++;
+ if (**argv != '-') {
+ usage(arg0);
+ exit(1);
+ }
+
+ fd = -1;
+ switch (argv[0][1]) {
+ case 'h' :
+ usage(arg0);
+ exit(0);
+ break;
+ case 'v' :
+ verbose++;
+ break;
+ case 'c' :
+ cmd++; cmdstep = 0;
+ fd = cfd;
+ break;
+ case 's' :
+ cmd++; cmdstep = 0;
+ if (sfd < 0)
+ do_acc(lfd);
+ if (sfd < 0)
+ die("accept()");
+ fd = sfd;
+ break;
+ case 'l' :
+ cmd++; cmdstep = 0;
+ fd = lfd;
+ break;
+ default : usage(arg0); exit(1); break;
+ }
+
+ if (fd >= 0) { /* an action is required */
+ if (argc < 2) {
+ usage(arg0);
+ exit(1);
+ }
+
+ for (word = argv[1]; word && *word; word = next) {
+ next = strchr(word, ',');
+ if (next)
+ *(next++) = 0;
+ cmdstep++;
+ if (strcmp(word, "acc") == 0) {
+ do_acc(fd);
+ }
+ else if (strcmp(word, "snd") == 0) {
+ do_snd(fd);
+ }
+ else if (strcmp(word, "mor") == 0) {
+ do_mor(fd);
+ }
+ else if (strcmp(word, "rcv") == 0) {
+ do_rcv(fd);
+ }
+ else if (strcmp(word, "drn") == 0) {
+ do_drn(fd);
+ }
+ else if (strcmp(word, "shb") == 0) {
+ do_shb(fd);
+ }
+ else if (strcmp(word, "shr") == 0) {
+ do_shr(fd);
+ }
+ else if (strcmp(word, "shw") == 0) {
+ do_shw(fd);
+ }
+ else if (strcmp(word, "lin") == 0) {
+ do_lin(fd);
+ }
+ else if (strcmp(word, "clo") == 0) {
+ do_clo(fd);
+ }
+ else if (strcmp(word, "pol") == 0) {
+ do_pol(fd);
+ }
+ else {
+ printf("Ignoring unknown action '%s' in step #%d of cmd #%d\n", word, cmdstep, cmd);
+ }
+ }
+ argc--; argv++;
+ }
+ }
+
+ write(1, "#### END ####\n", 14); // add a visible delimiter in the traces
+
+ if (!cmd) {
+ printf("No command was requested!\n");
+ usage(arg0);
+ exit(1);
+ }
+
+ return 0;
+}