pgsql: In pg_log_generic(), be more paranoid about preserving errno.

In pg_log_generic(), be more paranoid about preserving errno.

This code failed to account for the possibility that malloc() would
change errno, resulting in wrong output for %m, not to mention the
possibility of message truncation. Such a change is obviously
expected when malloc fails, but there's reason to fear that on some
platforms even a successful malloc call can modify errno.

Discussion: https://postgr.es/m/2576.1527382833@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fb30c9c1c5c36989d6b93906986358cb96936d64

Modified Files
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src/common/logging.c | 2 ++
1 file changed, 2 insertions(+)