/* Debian wrapper program for PostgreSQL front-ends.

     Copyright (c) Oliver Elphick 1998
     Licensing: Anyone may use this code under the same terms as the
             Debian PostgreSQL database package code, of which it is
             a part and with which it is released.

     This program is used to set the envelope from the configuration in
     /etc/postgresql/postmaster, so that programs know where to find
     the PostgreSQL library and database.
*/

#define _GNU_SOURCE

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>

#define    DO_NOT_OVERWRITE    0

void read_env();
void no_database();

char * progname;

int main (int argc, char **argv)
{
    char cmd[128] = "/usr/lib/postgresql/bin/\0";
    char *dbname = NULL, *p, **q;

    progname = argv[0];
    read_env();

    /* Write the default values into the environment */
    setenv("PGPORT", "5432", DO_NOT_OVERWRITE);
    setenv("PAGER", "/usr/bin/pager", DO_NOT_OVERWRITE);

    /* identify the command */
    if ((p = rindex(argv[0], '/')))
    {
        ++p;
    } else {
        p = argv[0];
    }
    strncat (cmd, p, 100);
    argv[0] = rindex(cmd, '/') + 1;

    /* This program should not be called as `pg_wrapper' */
    if (!strcmp(argv[0],"pg_wrapper"))
    {
	    fprintf(stderr,"pg_wrapper cannot be run as itself, but only through a link\nwhose name is that of the real program to be run.\n");
	    exit(1);
    }

    /* Special processing for  psql */
    if (!strcmp(argv[0],"psql"))
    {
        int ix = 0;
        /* Check the command line */
        char *z[128];
        char newopt[3] = "--";
        int c;
		  static struct option long_options[] =
		  {
			  {"echo-all", no_argument, 0, 'a'},
			  {"no-align", no_argument, 0, 'A'},
			  {"command", required_argument, 0, 'c'},
			  {"dbname", required_argument, 0, 'd'},
			  {"echo-queries", no_argument, 0, 'e'},
			  {"echo-hidden", no_argument, 0, 'E'},
			  {"file", required_argument, 0, 'f'},
			  {"field-separator", required_argument, 0, 'F'},
			  {"host", required_argument, 0, 'h'},
			  {"html", no_argument, 0, 'H'},
			  {"list", no_argument, 0, 'l'},
			  {"no-readline", no_argument, 0, 'n'},
			  {"output", required_argument, 0, 'o'},
			  {"port", required_argument, 0, 'p'},
			  {"pset", required_argument, 0, 'P'},
			  {"quiet", no_argument, 0, 'q'},
			  {"record-separator", required_argument, 0, 'R'},
			  {"single-step", no_argument, 0, 's'},
			  {"single-line", no_argument, 0, 'S'},
			  {"tuples-only", no_argument, 0, 't'},
			  {"table-attr", required_argument, 0, 'T'},
			  {"username", required_argument, 0, 'U'},
			  {"variable", required_argument, 0, 'v'},
			  {"set", required_argument, 0, 'v'},
			  {"version", no_argument, 0, 'V'},
			  {"password", no_argument, 0, 'W'},
			  {"expanded", no_argument, 0, 'x'},
			  {"no-psqlrc", no_argument, 0, 'X'},
			  {"help", no_argument, 0, '?'},
			  {0, 0, 0, 0}
		  };
		  int option_index = 0;

        while ((c = getopt_long(argc, argv, "aAc:d:Eef:F:h:Hlno:p:P:qR:sStT:uU:v:VWxX?", long_options, &option_index)) != EOF)
        {
            switch (c)
            {
                case 'd':
                    dbname = strdup(argv[optind-1]);
                    break;
                case 'c':
                case 'f':
                case 'F':
                case 'h':
                case 'o':
                case 'P':
                case 'p':
                case 'R':
                case 'T':
                case 'U':
                case 'v':
                    /* add option and argument to command line */
                    newopt[1] = c;
                    z[++ix] = strdup(newopt);
                    z[++ix] = strdup(optarg);
                    break;

                case 'l':
                case 'V':
		    dbname = strdup("template1");
                case 'a':
                case 'A':
                case 'e':
                case 'E':
                case 'H':
		case 'n':
                case 'q':
                case 's':
                case 'S':
                case 't':
                case 'u':
                case 'W':
                case 'x':
                case 'X':
                case '?':
                    /* add option to command line */
                    newopt[1] = c;
                    z[++ix] = strdup(newopt);
		    if (c == '?')
		    {
			z[++ix] = NULL;
			q = z;
			goto run_command;  /* yuk - a goto!!! */
		    }
                    break;

                default:
                     /* an error message has been printed by getopt() */
	             exit(1);
            }
        }

        if (!dbname && argv[optind] != NULL)
		  {
				dbname = strdup(argv[optind++]);

				if (argv[optind] != NULL)
				{
					/* Remaining argument is the user name */
					z[++ix] = "-U";
					z[++ix] = argv[optind];
				}
		  }

	if (!dbname)
	{
		char * pgdatabase;

		pgdatabase = getenv("PGDATABASE");
		if (pgdatabase)
		{
			int l;

			l = strlen(pgdatabase);
			if (l)
			{
				dbname = malloc(++l);
				strcpy(dbname, pgdatabase);
			} else {
				no_database();
			}
		} else {
			no_database();
		}
	}

	z[++ix] = "-d";
	z[++ix] = dbname;
	z[++ix] = NULL;
	q = z;
    } else {
        q = argv;
    }

run_command:
    /* Run the real command */
    q[0] = cmd;
    execv(cmd, q);

    /* If we get here, the execv() failed */
    fprintf(stderr, "Could not execv %s\n", cmd);
    return(255);
}

void no_database()
{
			fprintf(stderr, "%s (pg_wrapper): No database specified\n",
					progname);
			exit(1);
}

/* read_env()
 * Read the default environment from postgresql.env
 */
void
read_env()
{
	char *evar = NULL;
	char *value = NULL;
	char cmd[] = "env - /usr/lib/postgresql/bin/readpgenv";
	size_t sz = 0, sz2 = 0;
	FILE *input;
	fd_set fds;

	input = popen(cmd, "r");
	if (!input)
	{
		fprintf(stderr,"Could not run %s\n", cmd);
		exit(1);
	}

	FD_ZERO(&fds);
	FD_SET(fileno(input), &fds);
	select(fileno(input) + 1, &fds, NULL, NULL, NULL);

	while (getdelim(&evar, &sz, '=', input) >= 0)
			{
				if (getdelim(&value, &sz2, '\n', input) >= 0)
				{
					if (!strcmp(evar,"_"))
					{
						setenv(evar, value, DO_NOT_OVERWRITE);
					}
				} else {
					fprintf(stderr, "Unexpected input from %s:\n%s=%s\n", cmd, evar, value);
					exit(2);
				}
			}
	pclose(input);
}