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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2023-11-02 11:47:33 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2023-11-02 11:47:33 -0400 |
| commit | 65810fc6d0f6ccd3166713b9ec2f856be535383f (patch) | |
| tree | eb8b985ee287718226be38fb0d77e298f3f552ab /src/backend/utils/misc | |
| parent | 616de5bb35734d2b88b2d3bc9a685925def893f2 (diff) | |
| download | postgresql-65810fc6d0f6ccd3166713b9ec2f856be535383f.tar.gz postgresql-65810fc6d0f6ccd3166713b9ec2f856be535383f.zip | |
Be more wary about NULL values for GUC string variables.
get_explain_guc_options() crashed if a string GUC marked GUC_EXPLAIN
has a NULL boot_val. Nosing around found a couple of other places
that seemed insufficiently cautious about NULL string values, although
those are likely unreachable in practice. Add some commentary
defining the expectations for NULL values of string variables,
in hopes of forestalling future additions of more such bugs.
Xing Guo, Aleksander Alekseev, Tom Lane
Discussion: https://postgr.es/m/CACpMh+AyDx5YUpPaAgzVwC1d8zfOL4JoD-uyFDnNSa1z0EsDQQ@mail.gmail.com
Diffstat (limited to 'src/backend/utils/misc')
| -rw-r--r-- | src/backend/utils/misc/guc.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index bd03965a759..22d43287e36 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -8965,7 +8965,14 @@ get_explain_guc_options(int *num) { struct config_string *lconf = (struct config_string *) conf; - modified = (strcmp(lconf->boot_val, *(lconf->variable)) != 0); + if (lconf->boot_val == NULL && + *lconf->variable == NULL) + modified = false; + else if (lconf->boot_val == NULL || + *lconf->variable == NULL) + modified = true; + else + modified = (strcmp(lconf->boot_val, *(lconf->variable)) != 0); } break; @@ -9720,7 +9727,8 @@ write_one_nondefault_variable(FILE *fp, struct config_generic *gconf) { struct config_string *conf = (struct config_string *) gconf; - fprintf(fp, "%s", *conf->variable); + if (*conf->variable) + fprintf(fp, "%s", *conf->variable); } break; |