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nc: exit when both stdin and network are closed.

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function                                             old     new   delta
nc_main                                             1051    1042      -9
readwrite                                            943     887     -56

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-07-28 22:23:12 +02:00
parent ca54b662e7
commit ffeeb7a96c
1 changed files with 31 additions and 19 deletions
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50
networking/nc_bloaty.c
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@ -48,6 +48,12 @@
* - TCP connects from wrong ip/ports (if peer ip:port is specified * - TCP connects from wrong ip/ports (if peer ip:port is specified
* on the command line, but accept() says that it came from different addr) * on the command line, but accept() says that it came from different addr)
* are closed, but we don't exit - we continue to listen/accept. * are closed, but we don't exit - we continue to listen/accept.
* Since bbox 1.22:
* - nc exits when _both_ stdin and network are closed.
* This makes these two commands:
* echo "Yes" | nc 127.0.0.1 1234
* echo "no" | nc -lp 1234
* exchange their data _and exit_ instead of being stuck.
*/ */
/* done in nc.c: #include "libbb.h" */ /* done in nc.c: #include "libbb.h" */
@ -134,8 +140,6 @@ struct globals {
jmp_buf jbuf; /* timer crud */ jmp_buf jbuf; /* timer crud */
fd_set ding1; /* for select loop */
fd_set ding2;
char bigbuf_in[BIGSIZ]; /* data buffers */ char bigbuf_in[BIGSIZ]; /* data buffers */
char bigbuf_net[BIGSIZ]; char bigbuf_net[BIGSIZ];
}; };
@ -147,8 +151,6 @@ struct globals {
#define themaddr (G.themaddr ) #define themaddr (G.themaddr )
#define remend (G.remend ) #define remend (G.remend )
#define jbuf (G.jbuf ) #define jbuf (G.jbuf )
#define ding1 (G.ding1 )
#define ding2 (G.ding2 )
#define bigbuf_in (G.bigbuf_in ) #define bigbuf_in (G.bigbuf_in )
#define bigbuf_net (G.bigbuf_net) #define bigbuf_net (G.bigbuf_net)
#define o_verbose (G.o_verbose ) #define o_verbose (G.o_verbose )
@ -592,10 +594,17 @@ static int readwrite(void)
unsigned netretry; /* net-read retry counter */ unsigned netretry; /* net-read retry counter */
unsigned wretry; /* net-write sanity counter */ unsigned wretry; /* net-write sanity counter */
unsigned wfirst; /* one-shot flag to skip first net read */ unsigned wfirst; /* one-shot flag to skip first net read */
unsigned fds_open;
/* if you don't have all this FD_* macro hair in sys/types.h, you'll have to /* if you don't have all this FD_* macro hair in sys/types.h, you'll have to
either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */ either find it or do your own bit-bashing: *ding1 |= (1 << fd), etc... */
FD_SET(netfd, &ding1); /* global: the net is open */ fd_set ding1; /* for select loop */
fd_set ding2;
FD_ZERO(&ding1);
FD_SET(netfd, &ding1);
FD_SET(STDIN_FILENO, &ding1);
fds_open = 2;
netretry = 2; netretry = 2;
wfirst = 0; wfirst = 0;
rzleft = rnleft = 0; rzleft = rnleft = 0;
@ -604,7 +613,8 @@ static int readwrite(void)
errno = 0; /* clear from sleep, close, whatever */ errno = 0; /* clear from sleep, close, whatever */
/* and now the big ol' select shoveling loop ... */ /* and now the big ol' select shoveling loop ... */
while (FD_ISSET(netfd, &ding1)) { /* i.e. till the *net* closes! */ /* nc 1.10 has "while (FD_ISSET(netfd)" here */
while (fds_open) {
wretry = 8200; /* more than we'll ever hafta write */ wretry = 8200; /* more than we'll ever hafta write */
if (wfirst) { /* any saved stdin buffer? */ if (wfirst) { /* any saved stdin buffer? */
wfirst = 0; /* clear flag for the duration */ wfirst = 0; /* clear flag for the duration */
@ -629,13 +639,14 @@ static int readwrite(void)
/* if we have a timeout AND stdin is closed AND we haven't heard anything /* if we have a timeout AND stdin is closed AND we haven't heard anything
from the net during that time, assume it's dead and close it too. */ from the net during that time, assume it's dead and close it too. */
if (rr == 0) { if (rr == 0) {
if (!FD_ISSET(STDIN_FILENO, &ding1)) if (!FD_ISSET(STDIN_FILENO, &ding1)) {
netretry--; /* we actually try a coupla times. */ netretry--; /* we actually try a coupla times. */
if (!netretry) { if (!netretry) {
if (o_verbose > 1) /* normally we don't care */ if (o_verbose > 1) /* normally we don't care */
fprintf(stderr, "net timeout\n"); fprintf(stderr, "net timeout\n");
close(netfd); close(netfd);
return 0; /* not an error! */ return 0; /* not an error! */
}
} }
} /* select timeout */ } /* select timeout */
/* xxx: should we check the exception fds too? The read fds seem to give /* xxx: should we check the exception fds too? The read fds seem to give
@ -649,7 +660,8 @@ static int readwrite(void)
/* nc 1.10 doesn't do this */ /* nc 1.10 doesn't do this */
bb_perror_msg("net read"); bb_perror_msg("net read");
} }
FD_CLR(netfd, &ding1); /* net closed, we'll finish up... */ FD_CLR(netfd, &ding1); /* net closed */
fds_open--;
rzleft = 0; /* can't write anymore: broken pipe */ rzleft = 0; /* can't write anymore: broken pipe */
} else { } else {
rnleft = rr; rnleft = rr;
@ -671,9 +683,10 @@ Debug("got %d from the net, errno %d", rr, errno);
if (rr <= 0) { /* at end, or fukt, or ... */ if (rr <= 0) { /* at end, or fukt, or ... */
FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */ FD_CLR(STDIN_FILENO, &ding1); /* disable and close stdin */
close(STDIN_FILENO); close(STDIN_FILENO);
// Does it make sense to shutdown(net_fd, SHUT_WR) /* Let peer know we have no more data */
// to let other side know that we won't write anything anymore? /* nc 1.10 doesn't do this: */
// (and what about keeping compat if we do that?) shutdown(netfd, SHUT_WR);
fds_open--;
} else { } else {
rzleft = rr; rzleft = rr;
zp = bigbuf_in; zp = bigbuf_in;
@ -725,7 +738,7 @@ Debug("wrote %d to net, errno %d", rr, errno);
errno = 0; /* clear from sleep */ errno = 0; /* clear from sleep */
continue; /* ...with hairy select loop... */ continue; /* ...with hairy select loop... */
} }
if ((rzleft) || (rnleft)) { /* shovel that shit till they ain't */ if (rzleft || rnleft) { /* shovel that shit till they ain't */
wretry--; /* none left, and get another load */ wretry--; /* none left, and get another load */
goto shovel; goto shovel;
} }
@ -876,9 +889,8 @@ int nc_main(int argc UNUSED_PARAM, char **argv)
} }
#endif #endif
FD_SET(STDIN_FILENO, &ding1); /* stdin *is* initially open */
if (proggie) { if (proggie) {
close(0); /* won't need stdin */ close(STDIN_FILENO); /* won't need stdin */
option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */ option_mask32 &= ~OPT_o; /* -o with -e is meaningless! */
} }
#if ENABLE_NC_EXTRA #if ENABLE_NC_EXTRA