command.c

PostgreSQL7.4.6 for Linux

	/* \set -- generalized set variable/option command */
	else if (strcmp(cmd, "set") == 0)
	{
		char	   *opt0 = scan_option(&string, OT_NORMAL, NULL, false);

		if (!opt0)
		{
			/* list all variables */
			PrintVariables(pset.vars);
			success = true;
		}
		else
		{
			/*
			 * Set variable to the concatenation of the arguments.
			 */
			char	   *newval = NULL;
			char	   *opt;

			opt = scan_option(&string, OT_NORMAL, NULL, false);
			newval = xstrdup(opt ? opt : "");
			free(opt);

			while ((opt = scan_option(&string, OT_NORMAL, NULL, false)))
			{
				newval = realloc(newval, strlen(newval) + strlen(opt) + 1);
				if (!newval)
				{
					psql_error("out of memory\n");
					exit(EXIT_FAILURE);
				}
				strcat(newval, opt);
				free(opt);
			}

			if (SetVariable(pset.vars, opt0, newval))
			{
				/* Check for special variables */
				if (strcmp(opt0, "VERBOSITY") == 0)
					SyncVerbosityVariable();
			}
			else
			{
				psql_error("\\%s: error\n", cmd);
				success = false;
			}
			free(newval);
		}
		free(opt0);
	}

	/* \t -- turn off headers and row count */
	else if (strcmp(cmd, "t") == 0)
		success = do_pset("tuples_only", NULL, &pset.popt, quiet);


	/* \T -- define html <table ...> attributes */
	else if (strcmp(cmd, "T") == 0)
	{
		char	   *value = scan_option(&string, OT_NORMAL, NULL, false);

		success = do_pset("tableattr", value, &pset.popt, quiet);
		free(value);
	}

	/* \timing -- toggle timing of queries */
	else if (strcmp(cmd, "timing") == 0)
	{
		pset.timing = !pset.timing;
		if (!quiet)
		{
			if (pset.timing)
				puts(gettext("Timing is on."));
			else
				puts(gettext("Timing is off."));
		}
	}

	/* \unset */
	else if (strcmp(cmd, "unset") == 0)
	{
		char	   *opt = scan_option(&string, OT_NORMAL, NULL, false);

		if (!opt)
		{
			psql_error("\\%s: missing required argument\n", cmd);
			success = false;
		}
		else if (!SetVariable(pset.vars, opt, NULL))
		{
			psql_error("\\%s: error\n", cmd);
			success = false;
		}
		free(opt);
	}

	/* \w -- write query buffer to file */
	else if (strcmp(cmd, "w") == 0 || strcmp(cmd, "write") == 0)
	{
		FILE	   *fd = NULL;
		bool		is_pipe = false;
		char	   *fname = NULL;

		if (!query_buf)
		{
			psql_error("no query buffer\n");
			status = CMD_ERROR;
		}
		else
		{
			fname = scan_option(&string, OT_FILEPIPE, NULL, true);

			if (!fname)
			{
				psql_error("\\%s: missing required argument\n", cmd);
				success = false;
			}
			else
			{
				if (fname[0] == '|')
				{
					is_pipe = true;
					fd = popen(&fname[1], "w");
				}
				else
					fd = fopen(fname, "w");

				if (!fd)
				{
					psql_error("%s: %s\n", fname, strerror(errno));
					success = false;
				}
			}
		}

		if (fd)
		{
			int			result;

			if (query_buf && query_buf->len > 0)
				fprintf(fd, "%s\n", query_buf->data);

			if (is_pipe)
				result = pclose(fd);
			else
				result = fclose(fd);

			if (result == EOF)
			{
				psql_error("%s: %s\n", fname, strerror(errno));
				success = false;
			}
		}

		free(fname);
	}

	/* \x -- toggle expanded table representation */
	else if (strcmp(cmd, "x") == 0)
		success = do_pset("expanded", NULL, &pset.popt, quiet);


	/* \z -- list table rights (equivalent to \dp) */
	else if (strcmp(cmd, "z") == 0)
	{
		char	   *pattern = scan_option(&string, OT_NORMAL, NULL, true);

		success = permissionsList(pattern);
		if (pattern)
			free(pattern);
	}

	/* \! -- shell escape */
	else if (strcmp(cmd, "!") == 0)
	{
		success = do_shell(options_string);
		/* wind pointer to end of line */
		if (string)
			string += strlen(string);
	}

	/* \? -- slash command help */
	else if (strcmp(cmd, "?") == 0)
		slashUsage(pset.popt.topt.pager);

#if 0

	/*
	 * These commands don't do anything. I just use them to test the
	 * parser.
	 */
	else if (strcmp(cmd, "void") == 0 || strcmp(cmd, "#") == 0)
	{
		int			i = 0;
		char	   *value;

		fprintf(stderr, "+ optstr = |%s|\n", options_string);
		while ((value = scan_option(&string, OT_NORMAL, NULL, true)))
		{
			fprintf(stderr, "+ opt(%d) = |%s|\n", i++, value);
			free(value);
		}
	}
#endif

	else
		status = CMD_UNKNOWN;

	if (!success)
		status = CMD_ERROR;

	/* eat the rest of the options string */
	while ((val = scan_option(&string, OT_NORMAL, NULL, false)))
	{
		if (status != CMD_UNKNOWN)
			psql_error("\\%s: extra argument \"%s\" ignored\n", cmd, val);
		if (val)
			free(val);
	}

	if (options_string && continue_parse)
		*continue_parse = options_string + (string - string_cpy);
	free(string_cpy);

	return status;
}



/*
 * scan_option()
 *
 * *string points to possible option string on entry; on exit, it's updated
 * to point past the option string (if any).
 *
 * type tells what processing, if any, to perform on the option string;
 * for example, if it's a SQL identifier, we want to downcase any unquoted
 * letters.
 *
 * if quote is not NULL, *quote is set to 0 if no quoting was found, else
 * the quote symbol.
 *
 * if semicolon is true, trailing semicolon(s) that would otherwise be taken
 * as part of the option string will be stripped.
 *
 * Return value is NULL if no option found, else a malloc'd copy of the
 * processed option value.
 */
static char *
scan_option(char **string, enum option_type type, char *quote, bool semicolon)
{
	unsigned int pos;
	char	   *options_string;
	char	   *return_val;

	if (quote)
		*quote = 0;

	if (!string || !(*string))
		return NULL;

	options_string = *string;
	/* skip leading whitespace */
	pos = strspn(options_string, " \t\n\r");

	switch (options_string[pos])
	{
			/*
			 * End of line: no option present
			 */
		case '\0':
			*string = &options_string[pos];
			return NULL;

			/*
			 * Next command: treat like end of line
			 *
			 * XXX this means we can't conveniently accept options that start
			 * with a backslash; therefore, option processing that
			 * encourages use of backslashes is rather broken.
			 */
		case '\\':
			*string = &options_string[pos];
			return NULL;

			/*
			 * A single quote has a psql internal meaning, such as for
			 * delimiting file names, and it also allows for such escape
			 * sequences as \t.
			 */
		case '\'':
			{
				unsigned int jj;
				unsigned short int bslash_count = 0;

				for (jj = pos + 1; options_string[jj]; jj += PQmblen(&options_string[jj], pset.encoding))
				{
					if (options_string[jj] == '\'' && bslash_count % 2 == 0)
						break;

					if (options_string[jj] == '\\')
						bslash_count++;
					else
						bslash_count = 0;
				}

				if (options_string[jj] == 0)
				{
					psql_error("parse error at the end of line\n");
					*string = &options_string[jj];
					return NULL;
				}

				return_val = unescape(&options_string[pos + 1], jj - pos - 1);
				*string = &options_string[jj + 1];
				if (quote)
					*quote = '\'';
				return return_val;
			}

			/*
			 * Backticks are for command substitution, like in shells
			 */
		case '`':
			{
				bool		error = false;
				FILE	   *fd;
				char	   *file;
				PQExpBufferData output;
				char		buf[512];
				size_t		result,
							len;

				len = strcspn(options_string + pos + 1, "`");
				if (options_string[pos + 1 + len] == 0)
				{
					psql_error("parse error at the end of line\n");
					*string = &options_string[pos + 1 + len];
					return NULL;
				}

				options_string[pos + 1 + len] = '\0';
				file = options_string + pos + 1;

				fd = popen(file, "r");
				if (!fd)
				{
					psql_error("%s: %s\n", file, strerror(errno));
					error = true;
				}

				initPQExpBuffer(&output);

				if (!error)
				{
					do
					{
						result = fread(buf, 1, 512, fd);
						if (ferror(fd))
						{
							psql_error("%s: %s\n", file, strerror(errno));
							error = true;
							break;
						}
						appendBinaryPQExpBuffer(&output, buf, result);
					} while (!feof(fd));
					appendPQExpBufferChar(&output, '\0');
				}

				if (fd && pclose(fd) == -1)
				{
					psql_error("%s: %s\n", file, strerror(errno));
					error = true;
				}

				if (!error)
				{
					if (output.data[strlen(output.data) - 1] == '\n')
						output.data[strlen(output.data) - 1] = '\0';
					return_val = output.data;
				}
				else
				{
					return_val = xstrdup("");
					termPQExpBuffer(&output);
				}

				options_string[pos + 1 + len] = '`';
				*string = options_string + pos + len + 2;
				if (quote)
					*quote = '`';
				return return_val;
			}

			/*
			 * Variable substitution
			 */
		case ':':
			{
				size_t		token_end;
				const char *value;
				char		save_char;

				token_end = strcspn(&options_string[pos + 1], " \t\n\r");
				save_char = options_string[pos + token_end + 1];
				options_string[pos + token_end + 1] = '\0';
				value = GetVariable(pset.vars, options_string + pos + 1);
				return_val = xstrdup(value ? value : "");
				options_string[pos + token_end + 1] = save_char;
				*string = &options_string[pos + token_end + 1];
				/* XXX should we set *quote to ':' here? */
				return return_val;
			}

			/*
			 * | could be the beginning of a pipe if so, take rest of line
			 * as command
			 */
		case '|':
			if (type == OT_FILEPIPE)
			{
				*string += strlen(*string);
				return xstrdup(options_string + pos);
			}
			/* fallthrough for other option types */

			/*
			 * Default case: token extends to next whitespace, except that
			 * whitespace within double quotes doesn't end the token.
			 *
			 * If we are processing the option as a SQL identifier, then
			 * downcase unquoted letters and remove double-quotes --- but
			 * doubled double-quotes become output double-quotes, per
			 * spec.
			 *
			 * Note that a string like FOO"BAR"BAZ will be converted to
			 * fooBARbaz; this is somewhat inconsistent with the SQL spec,
			 * which would have us parse it as several identifiers.  But
			 * for psql's purposes, we want a string like "foo"."bar" to
			 * be treated as one option, so there's little choice.
			 */
		default:
			{
				bool		inquotes = false;
				size_t		token_len;
				char	   *cp;

				/* Find end of option */

				cp = &options_string[pos];
				for (;;)
				{
					/* Find next quote, whitespace, or end of string */
					cp += strcspn(cp, "\" \t\n\r");
					if (inquotes)
					{
						if (*cp == '\0')
						{
							psql_error("parse error at the end of line\n");
							*string = cp;
							return NULL;
						}
						if (*cp == '"')
							inquotes = false;
						cp++;
					}
					else
					{
						if (*cp != '"')
							break;		/* whitespace or end of string */
						if (quote)
							*quote = '"';
						inquotes = true;
						cp++;
					}
				}

				*string = cp;

				/* Copy the option */
				token_len = cp - &options_string[pos];

				return_val = malloc(token_len + 1);
				if (!return_val)
				{
					psql_error("out of memory\n");
					exit(EXIT_FAILURE);
				}

				memcpy(return_val, &options_string[pos], token_len);
				return_val[token_len] = '\0';

				/* Strip any trailing semi-colons if requested */
				if (semicolon)
				{
					int			i;

					for (i = token_len - 1;
						 i >= 0 && return_val[i] == ';';
						 i--)
						 /* skip */ ;

					if (i < 0)
					{
						/* nothing left after stripping the semicolon... */
						free(return_val);
						return NULL;
					}

					if (i < (int) token_len - 1)
						return_val[i + 1] = '\0';
				}

				/*
				 * If SQL identifier processing was requested, then we
				 * strip out excess double quotes and downcase unquoted
				 * letters.
				 */
				if (type == OT_SQLID || type == OT_SQLIDHACK)
				{
					inquotes = false;
					cp = return_val;

					while (*cp)
					{
						if (*cp == '"')
						{
							if (inquotes && cp[1] == '"')
							{
								/* Keep the first quote, remove the second */
								cp++;
							}
							inquotes = !inquotes;
							/* Collapse out quote at *cp */
							memmove(cp, cp + 1, strlen(cp));
							/* do not advance cp */
						}
						else
						{
							if (!inquotes && type == OT_SQLID)
							{
								if (isupper((unsigned char) *cp))
									*cp = tolower((unsigned char) *cp);
							}
							cp += PQmblen(cp, pset.encoding);
						}
					}
				}

				return return_val;
			}
	}
}



/*
 * unescape
 *
 * Replaces \n, \t, and the like.
 *
 * The return value is malloc()'ed.
 */
static char *
unescape(const unsigned char *source, size_t len)
{
	const unsigned char *p;
	bool		esc = false;	/* Last character we saw was the escape
								 * character */
	char	   *destination,
			   *tmp;
	size_t		length;

#ifdef USE_ASSERT_CHECKING
	assert(source);
#endif

	length = Min(len, strlen(source)) + 1;

	tmp = destination = malloc(length);
	if (!tmp)
	{
		psql_error("out of memory\n");
		exit(EXIT_FAILURE);
	}

	for (p = source; p - source < (int) len && *p; p += PQmblen(p, pset.encoding))
	{
		if (esc)
		{
			char		c;

			switch (*p)
			{
				case 'n':
					c = '\n';
					break;
				case 't':
					c = '\t';
					break;
				case 'b':
					c = '\b';
					break;
				case 'r':
					c = '\r';
					break;
				case 'f':
					c = '\f';
					break;
				case '0':
				case '1':
				case '2':
				case '3':
				case '4':
				case '5':
				case '6':
				case '7':
				case '8':
				case '9':
					c = parse_char((char **) &p);
					break;

				default:
					c = *p;
			}
			*tmp++ = c;
			esc = false;
		}

		else if (*p == '\\')
			esc = true;

		else
		{
			int			i;
			const unsigned char *mp = p;

			for (i = 0; i < PQmblen(p, pset.encoding); i++)
				*tmp++ = *mp++;
			esc = false;
		}
	}

	*tmp = '\0';
	return destination;
}



/* do_connect
 * -- handler for \connect
 *
 * Connects to a database (new_dbname) as a certain user (new_user).
 * The new user can be NULL. A db name of "-" is the same as the old one.
 * (That is, the one currently in pset. But pset.db can also be NULL. A NULL
 * dbname is handled by libpq.)
 * Returns true if all ok, false if the new connection couldn't be established.
 * The old connection will be kept if the session is interactive.
 */
static bool
do_connect(const char *new_dbname, const char *new_user)
{
	PGconn	   *oldconn = pset.db;