dblogin: Test an Informix Login

dblogin is a small ESQL/C utility that tests whether a given username and password can actually log in to an Informix® server, and reports what the session sees once connected — the CURRENT user, DBINFO('dbhostname'), and the server version — as one JSON object or a single raw line. Deliberately minimal: no schema access beyond systables, which exists in every database on every version. Full source: dblogin.ec.

Build

esql -o dblogin dblogin.ec. The password-prompt length limit is detected per platform (unlimited on Linux via glibc's getpass(), 256 on Solaris via getpassphrase(), 128 on the BSDs, the platform's own PASS_MAX where published) — override with -DDBLOGIN_PROMPT_MAX=N at build time if a platform's real limit isn't one of those.

Usage

Two calling shapes. The first reads credentials as two lines on stdin, so a password never appears as a process argument:

$ dblogin ALIAS <<'EOF'
myuser
mypassword
EOF

The second takes flags, prompting for the password (no echo) if --password is omitted:

$ dblogin --server ALIAS --username myuser
Database password: 

Full option list: --server ALIAS (or --informixserver), --username USER (or --user), --password PASS, --sqlhosts PATH (to point at a non-default sqlhosts file before connecting), --database NAME (default sysmaster), and --output json|raw.

Output

JSON (the default):

{"success":true,"sqlcode":0,"current":"myuser","host":"zeus","version":"IBM Informix Dynamic Server Version 14.10..."}

Raw (--output raw): the same three fields, space-separated, for shell scripting without a JSON parser:

myuser  zeus  IBM Informix Dynamic Server Version 14.10...

On failure, both formats report sqlcode and the real Informix error text rather than a bare exit code alone:

{"success":false,"sqlcode":-951,"isam":0,"stage":"connect","error":"Incorrect password or user myuser@host[alias] is not known on the database server."}

Exit codes

0 success, 1 SQL failure (connect or query), 2 input/usage failure (bad arguments, unreadable sqlhosts, a password that reached the platform's no-echo prompt limit and may have been silently truncated).