* [PATCH v3] Add RES_OPTIONS support for resolv.conf options overriding
@ 2017-04-25 19:45 Stefan Sedich
2017-04-25 20:49 ` Alexander Monakov
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Sedich @ 2017-04-25 19:45 UTC (permalink / raw)
To: musl; +Cc: Stefan Sedich
Currently glibc supports using the RES_OPTIONS environment variable
to customize the resolv.conf options on a per-process basis, this
adds the same support to musl
---
Changes in v3:
- initialize res_opts_env
src/network/resolvconf.c | 49 ++++++++++++++++++++++++++++++------------------
1 file changed, 31 insertions(+), 18 deletions(-)
diff --git a/src/network/resolvconf.c b/src/network/resolvconf.c
index 4c3e4c4b..177c6877 100644
--- a/src/network/resolvconf.c
+++ b/src/network/resolvconf.c
@@ -5,6 +5,30 @@
#include <string.h>
#include <netinet/in.h>
+void __parse_resolv_opts(struct resolvconf *conf, char *opts)
+{
+ char *p, *z;
+
+ p = strstr(opts, "ndots:");
+ if (p && isdigit(p[6])) {
+ p += 6;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->ndots = x > 15 ? 15 : x;
+ }
+ p = strstr(opts, "attempts:");
+ if (p && isdigit(p[9])) {
+ p += 9;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->attempts = x > 10 ? 10 : x;
+ }
+ p = strstr(opts, "timeout:");
+ if (p && (isdigit(p[8]) || p[8]=='.')) {
+ p += 8;
+ unsigned long x = strtoul(p, &z, 10);
+ if (z != p) conf->timeout = x > 60 ? 60 : x;
+ }
+}
+
int __get_resolv_conf(struct resolvconf *conf, char *search, size_t search_sz)
{
char line[256];
@@ -38,24 +62,7 @@ int __get_resolv_conf(struct resolvconf *conf, char *search, size_t search_sz)
continue;
}
if (!strncmp(line, "options", 7) && isspace(line[7])) {
- p = strstr(line, "ndots:");
- if (p && isdigit(p[6])) {
- p += 6;
- unsigned long x = strtoul(p, &z, 10);
- if (z != p) conf->ndots = x > 15 ? 15 : x;
- }
- p = strstr(line, "attempts:");
- if (p && isdigit(p[9])) {
- p += 9;
- unsigned long x = strtoul(p, &z, 10);
- if (z != p) conf->attempts = x > 10 ? 10 : x;
- }
- p = strstr(line, "timeout:");
- if (p && (isdigit(p[8]) || p[8]=='.')) {
- p += 8;
- unsigned long x = strtoul(p, &z, 10);
- if (z != p) conf->timeout = x > 60 ? 60 : x;
- }
+ __parse_resolv_opts(conf, line);
continue;
}
if (!strncmp(line, "nameserver", 10) && isspace(line[10])) {
@@ -89,5 +96,11 @@ no_resolv_conf:
conf->nns = nns;
+ char *res_opts_env = NULL;
+ if (!libc.secure) res_opts_env = getenv("RES_OPTIONS");
+ if (res_opts_env) {
+ __parse_resolv_opts(conf, res_opts_env);
+ }
+
return 0;
}
--
2.11.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] Add RES_OPTIONS support for resolv.conf options overriding
2017-04-25 19:45 [PATCH v3] Add RES_OPTIONS support for resolv.conf options overriding Stefan Sedich
@ 2017-04-25 20:49 ` Alexander Monakov
2017-04-25 20:56 ` Stefan Sedich
0 siblings, 1 reply; 3+ messages in thread
From: Alexander Monakov @ 2017-04-25 20:49 UTC (permalink / raw)
To: musl
I see a couple of pre-existing issues in options parsing
(not your problem, just questions for Rich):
On Tue, 25 Apr 2017, Stefan Sedich wrote:
> +void __parse_resolv_opts(struct resolvconf *conf, char *opts)
> +{
> + char *p, *z;
> +
> + p = strstr(opts, "ndots:");
This accepts xndots, _ndots, etc. I think this is undesirable, prefixing a
character could be seen by some users as a way to "comment-out" an option
without deleting it, and such loose matching lays a trap for them. It also
breaks if a valid option ending in 'ndots' appears in the future.
> + p = strstr(opts, "timeout:");
> + if (p && (isdigit(p[8]) || p[8]=='.')) {
> + p += 8;
> + unsigned long x = strtoul(p, &z, 10);
Either stroul should be strtod, or accepting p[8]=='.' is pointless.
This was introduced in commit d6cb08bcaca4ff1f921375510ca72bccea969c75
that moved this chunk of code from res_msend.c to resolvconf.c and
introduced p[8]=='.' check en passant.
> @@ -89,5 +96,11 @@ no_resolv_conf:
>
> conf->nns = nns;
>
> + char *res_opts_env = NULL;
> + if (!libc.secure) res_opts_env = getenv("RES_OPTIONS");
> + if (res_opts_env) {
> + __parse_resolv_opts(conf, res_opts_env);
> + }
This might look slightly cleaner if written as
if (!libc.secure) {
const char *opts = getenv("RES_OPTIONS");
if (opts) __parse_resolve_opts(conf, opts);
}
Alexander
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] Add RES_OPTIONS support for resolv.conf options overriding
2017-04-25 20:49 ` Alexander Monakov
@ 2017-04-25 20:56 ` Stefan Sedich
0 siblings, 0 replies; 3+ messages in thread
From: Stefan Sedich @ 2017-04-25 20:56 UTC (permalink / raw)
To: musl
[-- Attachment #1: Type: text/plain, Size: 1809 bytes --]
On Tue, Apr 25, 2017 at 1:50 PM Alexander Monakov <amonakov@ispras.ru>
wrote:
> I see a couple of pre-existing issues in options parsing
> (not your problem, just questions for Rich):
>
> On Tue, 25 Apr 2017, Stefan Sedich wrote:
> > +void __parse_resolv_opts(struct resolvconf *conf, char *opts)
> > +{
> > + char *p, *z;
> > +
> > + p = strstr(opts, "ndots:");
>
> This accepts xndots, _ndots, etc. I think this is undesirable, prefixing a
> character could be seen by some users as a way to "comment-out" an option
> without deleting it, and such loose matching lays a trap for them. It also
> breaks if a valid option ending in 'ndots' appears in the future.
>
> > + p = strstr(opts, "timeout:");
> > + if (p && (isdigit(p[8]) || p[8]=='.')) {
> > + p += 8;
> > + unsigned long x = strtoul(p, &z, 10);
>
> Either stroul should be strtod, or accepting p[8]=='.' is pointless.
> This was introduced in commit d6cb08bcaca4ff1f921375510ca72bccea969c75
> that moved this chunk of code from res_msend.c to resolvconf.c and
> introduced p[8]=='.' check en passant.
>
> > @@ -89,5 +96,11 @@ no_resolv_conf:
> >
> > conf->nns = nns;
> >
> > + char *res_opts_env = NULL;
> > + if (!libc.secure) res_opts_env = getenv("RES_OPTIONS");
> > + if (res_opts_env) {
> > + __parse_resolv_opts(conf, res_opts_env);
> > + }
>
> This might look slightly cleaner if written as
>
> if (!libc.secure) {
> const char *opts = getenv("RES_OPTIONS");
> if (opts) __parse_resolve_opts(conf, opts);
> }
>
> Alexander
>
Alexander,
I agree on the cleaner version :), I will await Rich to comment on the rest
before opening another patch as perhaps I can address some of these as part
of this commit if desired?
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2017-04-25 19:45 [PATCH v3] Add RES_OPTIONS support for resolv.conf options overriding Stefan Sedich
2017-04-25 20:49 ` Alexander Monakov
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