From: Andre Noll <maan@systemlinux.org>
Date: Sat, 8 Nov 2008 17:21:13 +0000 (+0100)
Subject: Output improvements.
X-Git-Tag: v0.0.5~1^2~25
X-Git-Url: http://git.tuebingen.mpg.de/?p=adu.git;a=commitdiff_plain;h=e14d98641f672c7b687b7259ce9dda130a60e3b4

Output improvements.

- Implement appending to an output file.
- Do not override the output file by default
- Implement piping the output into a command.
---

diff --git a/error.h b/error.h
index 00fbbc8..87d3fe2 100644
--- a/error.h
+++ b/error.h
@@ -32,6 +32,7 @@
 	_ERROR(UNIT, "no unit allowed here") \
 	_ERROR(BAD_UNIT, "invalid unit specifier") \
 	_ERROR(BAD_ATOM, "invalid atom") \
+	_ERROR(BAD_OUTPUT_ARG, "invalid name for output") \
 
 
 /**
diff --git a/select.c b/select.c
index e66b2dd..152e4b9 100644
--- a/select.c
+++ b/select.c
@@ -586,17 +586,102 @@ static int print_statistics(struct format_info *fi)
 	return -ERRNO_TO_ERROR(-EINVAL);
 }
 
-int run_select_query(struct uid_range *admissible_uids, struct format_info *fi)
+static int open_pipe(char *path)
 {
-	int ret;
+	int p[2], ret, argc;
+	char **argv;
 
-	if (select_conf.output_given && strcmp(select_conf.output_arg, "-")) {
-		output_file = fopen(select_conf.output_arg, "w");
+	ret = pipe(p);
+	if (ret < 0)
+		return ERRNO_TO_ERROR(errno);
+	ret = fork();
+	if (ret < 0)
+		return ERRNO_TO_ERROR(errno);
+	if (ret) { /* parent */
+		DEBUG_LOG("created process %d\n", ret);
+		close(p[0]);
+		output_file = fdopen(p[1], "w");
 		if (!output_file)
-			return -ERRNO_TO_ERROR(errno);
-	} else
-		output_file = stdout;
+			return ERRNO_TO_ERROR(errno);
+		return 1;
+	}
+	close(p[1]);
+	if (p[0] != STDIN_FILENO)
+		dup2(p[0], STDIN_FILENO);
+	DEBUG_LOG("executing %s\n", path);
+	argc = split_args(path, &argv, " \t");
+	execvp(argv[0], argv);
+	ERROR_LOG("error executing %s: %s\n", path,
+		adu_strerror(ERRNO_TO_ERROR(errno)));
+	_exit(EXIT_FAILURE);
+}
+
+static int open_output_stream(void)
+{
+	char *p;
+	int ret, flags = O_WRONLY | O_CREAT;
+
+	if (!select_conf.output_given)
+		goto use_stdout;
+	p = select_conf.output_arg;
+	switch (p[0]) {
+	case '\0': /* empty string */
+		goto bad_output_arg;
+	case '-':
+		if (!p[1]) /* "-" means stdout */
+			goto use_stdout;
+		/* string starting with a dash */
+		flags |= O_EXCL;
+		goto open_file;
+	case '>':
+		if (!p[1]) /* ">" is invalid */
+			goto bad_output_arg;
+		if (p[1] != '>') {
+			p++;
+			flags |= O_TRUNC;
+			goto open_file;
+		}
+		/* string starting with ">>" */
+		if (!p[2]) /* ">>" is invalid */
+			goto bad_output_arg;
+		flags |= O_APPEND;
+		p += 2;
+		goto open_file;
+	case '|':
+		if (!p[1]) /* "|" is invalid */
+			goto bad_output_arg;
+		p++;
+		return open_pipe(p);
+	default: /* args starts with no magic character */
+		flags |= O_EXCL;
+		goto open_file;
+	}
+use_stdout:
+	output_file = stdout;
+	return 1;
+bad_output_arg:
+	output_file = NULL;
+	return -E_BAD_OUTPUT_ARG;
+open_file:
+	/*
+	 * glibc's 'x' mode to fopen is not portable, so use open() and
+	 * fdopen().
+	 */
+	ret = open(p, flags, 0644);
+	if (ret < 0)
+		return -ERRNO_TO_ERROR(errno);
+	output_file = fdopen(ret, "w");
+	if (!output_file)
+		return -ERRNO_TO_ERROR(errno);
+	return 1;
+}
 
+int run_select_query(struct uid_range *admissible_uids, struct format_info *fi)
+{
+	int ret = open_output_stream();
+
+	if (ret < 0)
+		goto out;
 	ret = open_dir_table(0);
 	if (ret < 0)
 		goto out;
@@ -608,8 +693,10 @@ int run_select_query(struct uid_range *admissible_uids, struct format_info *fi)
 	ret = print_statistics(fi);
 out:
 	close_all_tables();
-	if (output_file != stdout)
+	if (output_file && output_file != stdout) {
 		fclose(output_file);
+		output_file = NULL;
+	}
 	return ret;
 }