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Use a dynamically-sized buffer for SIOCGIFCONF so that `ifconfig -a'

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actually retrieves all the information no matter how many interfaces
there are.  (Probably there are other utilities which need similar
modification.)

Submitted by:	Andrew Webster <awebster@dataradio.com>
This commit is contained in:
Garrett Wollman 1995-12-07 19:21:53 +00:00
parent 3d334e23c5
commit ee9a463848
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=12672
1 changed files with 26 additions and 9 deletions
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35
sbin/ifconfig/ifconfig.c
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@ -31,6 +31,11 @@
* SUCH DAMAGE.
*/
/*
* 951109 - Andrew@pubnix.net - Changed to iterative buffer growing mechanism
* for ifconfig -a so all interfaces are queried.
*
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1983, 1993\n\
@ -216,22 +221,33 @@ main(argc, argv)
exit(1);
}
if (strstr(name, "-a")) {
char *buffer;
struct ifconf ifc;
#define MAX_INTERFACES 50 /* Yeah right. */
char buffer[MAX_INTERFACES * sizeof(struct ifreq)];
struct ifreq *ifptr, *end;
int ifflags, selectflag = -1;
int oldbufsize, bufsize = sizeof(struct ifreq);
if (strstr(name, "-au"))
selectflag = 1;
if (strstr(name, "-ad"))
selectflag = 0;
ifc.ifc_len = sizeof(buffer);
ifc.ifc_buf = buffer;
if (ioctl(s, SIOCGIFCONF, (char *) &ifc) < 0) {
perror("ifconfig (SIOCGIFCONF)");
exit (1);
}
buffer = malloc(bufsize); /* allocate first buffer */
ifc.ifc_len = bufsize; /* Initial setting */
/*
* Itterate through here until we don't get any more data
*/
do {
oldbufsize = ifc.ifc_len;
bufsize += 1+sizeof(struct ifreq);
buffer = realloc((void *)buffer, bufsize);
ifc.ifc_len = bufsize;
ifc.ifc_buf = buffer;
if (ioctl(s, SIOCGIFCONF, (char *) &ifc) < 0) {
perror("ifconfig (SIOCGIFCONF)");
exit (1);
}
} while (ifc.ifc_len > oldbufsize);
ifflags = ifc.ifc_req->ifr_flags;
end = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len);
ifptr = ifc.ifc_req;
@ -243,7 +259,7 @@ main(argc, argv)
perror("ifconfig: socket");
exit(1);
}
if (ifptr->ifr_flags == ifflags)
if (ifptr->ifr_flags == ifflags)
ifconfig(argc,argv,af,rafp,selectflag);
if(ifptr->ifr_addr.sa_len) /* Dohw! */
ifptr = (struct ifreq *) ((caddr_t) ifptr +
@ -251,6 +267,7 @@ main(argc, argv)
sizeof(struct sockaddr));
ifptr++;
}
free(buffer);
} else
ifconfig(argc,argv,af,rafp, -1);