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authordab <dab@FreeBSD.org>2017-09-25 17:39:53 +0000
committerdab <dab@FreeBSD.org>2017-09-25 17:39:53 +0000
commitb3eb1ea10fd5d89b3608acaef0175dbd45fc6a6d (patch)
tree3d2d87e94a9940bf1518c4a9f4d29eb26031b76f
parente461c1a1152f0171722f8fbc75644dc6adaa6ffc (diff)
downloadFreeBSD-src-b3eb1ea10fd5d89b3608acaef0175dbd45fc6a6d.zip
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MFC r313107 (by danfe):
Try to fix the old "he capability is stupid" bug in gettytab(5)/getty(8) There is one capability explicitly documented in gettytab(5) as stupid: he. And it is indeed. It was meant to facilitate system hostname modification, but is hardly usable in practice because it allows very limited editing (e.g., it depends on a particular hostname length, making it non-generic). Replace it with simple implementation that treats ``he'' as POSIX extended regular expression which is matched against the hostname. If there are no parenthesized subexpressions in the pattern, entire matched string is used as the final hostname. Otherwise, use the first matched subexpression. If the pattern does not match, the original hostname is not modified. Using regex(3) gives more freedom, does not complicate the code very much, and makes a lot more sense, in turn making ``he'' less stupid and actually useful (e.g., it is now possible to obtain node or domain names from the original hostname string, without knowing it in advance). Approved by: vangyzen (mentor) Sponsored by: Dell EMC
-rw-r--r--libexec/getty/gettytab.527
-rw-r--r--libexec/getty/subr.c73
2 files changed, 48 insertions, 52 deletions
diff --git a/libexec/getty/gettytab.5 b/libexec/getty/gettytab.5
index 16cd15a..89c51c5 100644
--- a/libexec/getty/gettytab.5
+++ b/libexec/getty/gettytab.5
@@ -28,7 +28,7 @@
.\" from: @(#)gettytab.5 8.4 (Berkeley) 4/19/94
.\" $FreeBSD$
.\" "
-.Dd April 19, 1994
+.Dd February 2, 2017
.Dt GETTYTAB 5
.Os
.Sh NAME
@@ -118,7 +118,7 @@ character
.Em NOT
hangup line on last close
.It "he str" Ta Dv NULL Ta
-.No "hostname editing string"
+.No "hostname editing regular expression"
.It "hn str hostname hostname"
.It "ht bool false terminal has real tabs"
.It "hw bool false do cts/rts hardware flow control"
@@ -302,18 +302,13 @@ but may also be overridden by the
table entry.
In either case it may be edited with the
.Va \&he
-string.
-A '@' in the
-.Va \&he
-string causes one character from the real hostname to
-be copied to the final hostname.
-A '#' in the
-.Va \&he
-string causes the next character of the real hostname
-to be skipped.
-Each character that
-is neither '@' nor '#' is copied into the final hostname.
-Surplus '@' and '#' characters are ignored.
+POSIX
+.Dq extended
+regular expression, which is matched against the hostname.
+If there are no parenthesized subexpressions in the pattern,
+the entire matched string is used as the final hostname;
+otherwise, the first matched subexpression is used instead.
+If the pattern does not match, the original hostname is not modified.
.It \&%t
The tty name.
.It "\&%m, \&%r, \&%s, \&%v"
@@ -528,10 +523,6 @@ of the delay algorithms are not implemented.
The terminal driver should support sane delay settings.
.Pp
The
-.Va \&he
-capability is stupid.
-.Pp
-The
.Xr termcap 5
format is horrid, something more rational should
have been chosen.
diff --git a/libexec/getty/subr.c b/libexec/getty/subr.c
index 4716e97..2496b4c 100644
--- a/libexec/getty/subr.c
+++ b/libexec/getty/subr.c
@@ -43,6 +43,7 @@ static const char rcsid[] =
#include <sys/time.h>
#include <poll.h>
+#include <regex.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
@@ -53,8 +54,6 @@ static const char rcsid[] =
#include "pathnames.h"
#include "extern.h"
-
-
/*
* Get a table entry.
*/
@@ -469,42 +468,48 @@ adelay(int ms, struct delayval *dp)
char editedhost[MAXHOSTNAMELEN];
void
-edithost(const char *pat)
+edithost(const char *pattern)
{
- const char *host = HN;
- char *res = editedhost;
-
- if (!pat)
- pat = "";
- while (*pat) {
- switch (*pat) {
-
- case '#':
- if (*host)
- host++;
- break;
-
- case '@':
- if (*host)
- *res++ = *host++;
- break;
+ regex_t regex;
+ regmatch_t *match;
+ int found;
+
+ if (pattern == NULL || *pattern == '\0')
+ goto copyasis;
+ if (regcomp(&regex, pattern, REG_EXTENDED) != 0)
+ goto copyasis;
+
+ match = calloc(regex.re_nsub + 1, sizeof(*match));
+ if (match == NULL) {
+ regfree(&regex);
+ goto copyasis;
+ }
- default:
- *res++ = *pat;
- break;
+ found = !regexec(&regex, HN, regex.re_nsub + 1, match, 0);
+ if (found) {
+ size_t subex, totalsize;
- }
- if (res == &editedhost[sizeof editedhost - 1]) {
- *res = '\0';
- return;
- }
- pat++;
+ /*
+ * We found a match. If there were no parenthesized
+ * subexpressions in the pattern, use entire matched
+ * string as ``editedhost''; otherwise use the first
+ * matched subexpression.
+ */
+ subex = !!regex.re_nsub;
+ totalsize = match[subex].rm_eo - match[subex].rm_so + 1;
+ strlcpy(editedhost, HN + match[subex].rm_so, totalsize >
+ sizeof(editedhost) ? sizeof(editedhost) : totalsize);
}
- if (*host)
- strncpy(res, host, sizeof editedhost - (res - editedhost) - 1);
- else
- *res = '\0';
- editedhost[sizeof editedhost - 1] = '\0';
+ free(match);
+ regfree(&regex);
+ if (found)
+ return;
+ /*
+ * In case of any errors, or if the pattern did not match, pass
+ * the original hostname as is.
+ */
+ copyasis:
+ strlcpy(editedhost, HN, sizeof(editedhost));
}
static struct speedtab {
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