dect
/
libpcap
Archived
13
0
Fork 0
Code Releases Activity

Improve error messages from bpf_open(), and let it do the error handling. 

bpf_open() already handles returning the right PCAP_ERROR_ value and
setting p->errbuf; let it do its thing.

Enhance its thing so that it tries to do a better job of figuring out
what the problem is (no BPF devices at all, all BPF devices busy, no
permission to open BPF device, something else).
This commit is contained in:
Guy Harris 2010-05-18 18:50:30 -07:00
parent 0a77b1b15f
commit 06a81b2e72
1 changed files with 51 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
pcap-bpf.c
View File

@ -435,6 +435,10 @@ pcap_create(const char *device, char *ebuf)
return (p);
}
/*
* On success, returns a file descriptor for a BPF device.
* On failure, returns a PCAP_ERROR_ value, and sets p->errbuf.
*/
static int
bpf_open(pcap_t *p)
{
@ -495,12 +499,52 @@ bpf_open(pcap_t *p)
* XXX better message for all minors used
*/
if (fd < 0) {
if (errno == EACCES)
fd = PCAP_ERROR_PERM_DENIED;
else
switch (errno) {
case ENOENT:
fd = PCAP_ERROR;
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s",
device, pcap_strerror(errno));
if (n == 1) {
/*
* /dev/bpf0 doesn't exist, which
* means we probably have no BPF
* devices.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"(there are no BPF devices)");
} else {
/*
* We got EBUSY on at least one
* BPF device, so we have BPF
* devices, but all the ones
* that exist are busy.
*/
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"(all BPF devices are busy)");
}
break;
case EACCES:
/*
* Got EACCES on the last device we tried,
* and EBUSY on all devices before that,
* if any.
*/
fd = PCAP_ERROR_PERM_DENIED;
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"(cannot open BPF device) %s: %s", device,
pcap_strerror(errno));
break;
default:
/*
* Some other problem.
*/
fd = PCAP_ERROR;
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"(cannot open BPF device) %s: %s", device,
pcap_strerror(errno));
break;
}
}
#endif
@ -672,19 +716,8 @@ pcap_can_set_rfmon_bpf(pcap_t *p)
* First, open a BPF device.
*/
fd = bpf_open(p);
if (fd < 0) {
if (errno == EACCES) {
/*
* Sorry, you don't have permission to do capturing.
*/
return (PCAP_ERROR_PERM_DENIED);
} else {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"Can't open BPF device for %s: %s",
p->opt.source, pcap_strerror(errno));
return (PCAP_ERROR);
}
}
if (fd < 0)
return (fd); /* fd is the appropriate error code */
/*
* Now bind to the device.