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| author | Florian Weimer <fweimer@redhat.com> | 2024-07-24 12:06:47 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2024-07-24 12:07:45 +0200 |
| commit | 95f61610f3e481d191b6184432342236fd59186d (patch) | |
| tree | 6d386a0bcf03782379a5655054f9ee208ededcd5 | |
| parent | af625987d619388a100b153520d3ee308bda9889 (diff) | |
| download | glibc-95f61610f3e481d191b6184432342236fd59186d.zip glibc-95f61610f3e481d191b6184432342236fd59186d.tar.gz glibc-95f61610f3e481d191b6184432342236fd59186d.tar.bz2 | |
resolv: Support clearing option flags with a “-” prefix (bug 14799)
I think using a “-” prefix is less confusing than introducing
double-negation construct (“no-no-tld-query”).
Reviewed-by: DJ Delorie <dj@redhat.com>
| -rw-r--r-- | NEWS | 6 | ||||
| -rw-r--r-- | resolv/res_init.c | 28 | ||||
| -rw-r--r-- | resolv/tst-resolv-res_init-skeleton.c | 10 |
3 files changed, 30 insertions, 14 deletions
@@ -9,7 +9,11 @@ Version 2.41 Major new features: - [Add new features here] +* In /etc/resolv.conf and the RES_OPTIONS, option flags can now be + prefixed with “-” to clear previously set flags. For example, if + /etc/resolv.conf contains “options no-aaaa”, a process running with + the RES_OPTIONS=-no-aaaa environment variable performs AAAA DNS + queries when the glibc DNS stub resolver is used. Deprecated and removed features, and other changes affecting compatibility: diff --git a/resolv/res_init.c b/resolv/res_init.c index 263263d..243532b 100644 --- a/resolv/res_init.c +++ b/resolv/res_init.c @@ -682,27 +682,29 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options) { char str[22]; uint8_t len; - uint8_t clear; unsigned long int flag; } options[] = { #define STRnLEN(str) str, sizeof (str) - 1 - { STRnLEN ("rotate"), 0, RES_ROTATE }, - { STRnLEN ("edns0"), 0, RES_USE_EDNS0 }, - { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP }, - { STRnLEN ("single-request"), 0, RES_SNGLKUP }, - { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY }, - { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY }, - { STRnLEN ("no-reload"), 0, RES_NORELOAD }, - { STRnLEN ("use-vc"), 0, RES_USEVC }, - { STRnLEN ("trust-ad"), 0, RES_TRUSTAD }, - { STRnLEN ("no-aaaa"), 0, RES_NOAAAA }, + { STRnLEN ("rotate"), RES_ROTATE }, + { STRnLEN ("edns0"), RES_USE_EDNS0 }, + { STRnLEN ("single-request-reopen"), RES_SNGLKUPREOP }, + { STRnLEN ("single-request"), RES_SNGLKUP }, + { STRnLEN ("no_tld_query"), RES_NOTLDQUERY }, + { STRnLEN ("no-tld-query"), RES_NOTLDQUERY }, + { STRnLEN ("no-reload"), RES_NORELOAD }, + { STRnLEN ("use-vc"), RES_USEVC }, + { STRnLEN ("trust-ad"), RES_TRUSTAD }, + { STRnLEN ("no-aaaa"), RES_NOAAAA }, }; #define noptions (sizeof (options) / sizeof (options[0])) + bool negate_option = *cp == '-'; + if (negate_option) + ++cp; for (int i = 0; i < noptions; ++i) if (strncmp (cp, options[i].str, options[i].len) == 0) { - if (options[i].clear) - parser->template.options &= options[i].flag; + if (negate_option) + parser->template.options &= ~options[i].flag; else parser->template.options |= options[i].flag; break; diff --git a/resolv/tst-resolv-res_init-skeleton.c b/resolv/tst-resolv-res_init-skeleton.c index 6bef62c..d3a19eb 100644 --- a/resolv/tst-resolv-res_init-skeleton.c +++ b/resolv/tst-resolv-res_init-skeleton.c @@ -679,6 +679,16 @@ struct test_case test_cases[] = "; nameserver[0]: [192.0.2.1]:53\n", .res_options = "attempts:5 ndots:3 edns0 ", }, + {.name = "RES_OPTIONS can clear flags", + .conf = "options ndots:2 use-vc no-aaaa edns0\n" + "nameserver 192.0.2.1\n", + .expected = "options ndots:3 use-vc\n" + "search example.com\n" + "; search[0]: example.com\n" + "nameserver 192.0.2.1\n" + "; nameserver[0]: [192.0.2.1]:53\n", + .res_options = "ndots:3 -edns0 -no-aaaa", + }, {.name = "many search list entries (bug 19569)", .conf = "nameserver 192.0.2.1\n" "search corp.example.com support.example.com" |