[PATCH] nfs-utils: Enable adding of comments and date modified to nfs.conf files

[Alice J Mitchell <ajmitchell@redhat.com>]

Extend the nfs.conf editing code to support the inserting of comment
lines, as well as file modified information so that automated setting
adjustments and imports can be appropriately flagged.

Signed-off-by: Alice J Mitchell <ajmitchell@redhat.com>
---
 support/include/conffile.h |   2 +
 support/nfs/conffile.c     | 195 ++++++++++++++++++++++++++++++++++++++++++++-
 tools/nfsconf/nfsconf.man  |   7 +-
 tools/nfsconf/nfsconfcli.c |  12 ++-
 4 files changed, 211 insertions(+), 5 deletions(-)

diff --git a/support/include/conffile.h b/support/include/conffile.h
index a3340f9..7d974fe 100644
--- a/support/include/conffile.h
+++ b/support/include/conffile.h
@@ -69,6 +69,8 @@ extern int      conf_remove_section(int, const char *);
 extern void     conf_report(FILE *);
 extern int      conf_write(const char *, const char *, const char *, const char *, const char *);
 
+extern const char *modified_by;
+
 /*
  * Convert letter from upper case to lower case
  */
diff --git a/support/nfs/conffile.c b/support/nfs/conffile.c
index d8f2e8e..66d4215 100644
--- a/support/nfs/conffile.c
+++ b/support/nfs/conffile.c
@@ -51,6 +51,7 @@
 #include <syslog.h>
 #include <libgen.h>
 #include <sys/file.h>
+#include <time.h>
 
 #include "conffile.h"
 #include "xlog.h"
@@ -113,6 +114,8 @@ struct conf_binding {
 
 LIST_HEAD (conf_bindings, conf_binding) conf_bindings[256];
 
+const char *modified_by = NULL;
+
 static __inline__ uint8_t
 conf_hash(const char *s)
 {
@@ -1397,6 +1400,52 @@ make_section(const char *section, const char *arg)
 	return line;
 }
 
+/* compose a comment line (with or without tag) */
+static char *
+make_comment(const char *tag, const char *comment)
+{
+	char *line;
+	int ret;
+
+	if (tag == NULL || *tag == '\0') {
+		ret = asprintf(&line, "# %s\n", comment);
+	} else {
+		ret = asprintf(&line, "# %s: %s\n", tag, comment);
+	}
+
+	if (ret == -1) {
+		xlog(L_ERROR, "malloc error composing header");
+		return NULL;
+	}
+
+	return line;
+}
+		
+/* compose a 'file modified' comment */
+static char *
+make_timestamp(const char *tag, time_t when)
+{
+	struct tm *tstamp;
+	char datestr[80];
+	char *result = NULL;
+
+	tstamp = localtime(&when);
+	if (strftime(datestr, sizeof(datestr), "%b %d %Y %H:%M:%S", tstamp) == 0) {
+		xlog(L_ERROR, "error composing date");
+		datestr[0] = '\0';
+	}
+
+	if (modified_by) {
+		char *tmpstr = NULL;
+		asprintf(&tmpstr, "%s on %s", modified_by, datestr);
+		result = make_comment(tag, tmpstr);
+		free(tmpstr);
+	} else {
+		result = make_comment(tag, datestr);
+	}
+	return result;
+}
+
 /* does the supplied line contain the named section header */
 static bool
 is_section(const char *line, const char *section, const char *arg)
@@ -1406,6 +1455,10 @@ is_section(const char *line, const char *section, const char *arg)
 	char *sub;
 	bool found = false;
 
+	/* Not a valid section name  */
+	if (strcmp(section, "#") == 0)
+		return false;
+
 	/* skip leading white space */
 	while (*line == '[' || isspace(*line))
 		line++;
@@ -1569,6 +1622,54 @@ is_comment(const char *line)
 	return false;
 }
 
+/* check that line contains the specified comment header */
+static bool
+is_taggedcomment(const char *line, const char *field)
+{
+	char *end;
+	char *name;
+	bool found = false;
+
+	if (line == NULL)
+		return false;
+
+	while (isblank(*line))
+		line++;
+
+	if (*line != '#')
+		return false;
+
+	line++;
+
+	/* quick check, is this even a likely formatted line */
+	end = strchr(line, ':');
+	if (end == NULL)
+		return false;
+
+	/* skip leading white space before field name */
+	while (isblank(*line))
+		line++;
+
+	name = strdup(line);
+	if (name == NULL) {
+		xlog_warn("conf_write: malloc failed");
+		return false;
+	}
+
+	/* strip trailing spaces from the name */
+	end = strchr(name, ':');
+	if (end) *(end--) = 0;
+	while (end && end > name && isblank(*end))
+		*(end--)=0;
+
+	if (strcasecmp(name, field)==0) 
+		found = true;
+
+	free(name);
+	return found;
+}
+
+
 /* delete a buffer queue whilst optionally outputting to file */
 static int
 flush_outqueue(struct tailhead *queue, FILE *fout)
@@ -1772,6 +1873,7 @@ conf_write(const char *filename, const char *section, const char *arg,
 	struct tailhead inqueue;
 	char * buff = NULL;
 	int buffsize = 0;
+	time_t now = time(NULL);
 
 	TAILQ_INIT(&inqueue);
 	TAILQ_INIT(&outqueue);
@@ -1804,12 +1906,81 @@ conf_write(const char *filename, const char *section, const char *arg,
 		if (lock_file(infile))
 			goto cleanup;
 
-		if (append_line(&inqueue, NULL, make_section(section, arg)))
+		if (strcmp(section, "#") == 0) {
+			if (append_line(&inqueue, NULL, make_comment(tag, value)))
+				goto cleanup;
+		} else {
+			if (append_line(&inqueue, NULL, make_section(section, arg)))
+				goto cleanup;
+
+			if (append_line(&inqueue, NULL, make_tagline(tag, value)))
+				goto cleanup;
+		}
+
+		append_queue(&inqueue, &outqueue);
+	} else 
+	if (strcmp(section, "#") == 0) {
+		/* Adding a comment line */
+		struct outbuffer *where = NULL;
+		struct outbuffer *next = NULL;
+		bool found = false;
+		int err = 0;
+
+		if (lock_file(infile))
 			goto cleanup;
 
-		if (append_line(&inqueue, NULL, make_tagline(tag, value)))
+		buffsize = 4096;
+		buff = calloc(1, buffsize);
+		if (buff == NULL) {
+			xlog(L_ERROR, "malloc error for read buffer");
 			goto cleanup;
+		}
+		buff[0] = '\0';
 
+		/* read in the file */
+		do {
+			if (*buff != '\0' 
+			&& !is_taggedcomment(buff, "Modified")) {
+				if (append_line(&inqueue, NULL, strdup(buff)))
+					goto cleanup;
+			}
+
+			err = read_line(&buff, &buffsize, infile);
+		} while (err == 0);
+
+		/* if a tagged comment, look for an existing instance */
+		if (tag && *tag != '\0') {
+			where = TAILQ_FIRST(&inqueue);
+			while (where != NULL) {
+				next = TAILQ_NEXT(where, link);
+				struct outbuffer *prev = TAILQ_PREV(where, tailhead, link);
+				if (is_taggedcomment(where->text, tag)) {
+					TAILQ_REMOVE(&inqueue, where, link);
+					free(where->text);
+					free(where);
+					found = true;
+					if (append_line(&inqueue, prev, make_comment(tag, value)))
+						goto cleanup;
+				}
+				where = next;
+			}
+		}
+		/* it wasn't tagged or we didn't find it */
+		if (!found) {
+			/* does the file end in a blank line or a comment */
+			if (!TAILQ_EMPTY(&inqueue)) {
+				struct outbuffer *tail = TAILQ_LAST(&inqueue, tailhead);
+				if (tail && !is_empty(tail->text) && !is_comment(tail->text)) {
+					/* no, so add one for clarity */
+					if (append_line(&inqueue, NULL, strdup("\n")))
+						goto cleanup;
+				}
+			}
+			/* add the new comment line */
+			if (append_line(&inqueue, NULL, make_comment(tag, value)))
+				goto cleanup;
+		}
+		/* move everything over to the outqueue for writing */
 		append_queue(&inqueue, &outqueue);
 	} else {
 		bool found = false;
@@ -1831,7 +2002,8 @@ conf_write(const char *filename, const char *section, const char *arg,
 
 			/* read in one section worth of lines */
 			do {
-				if (*buff != '\0') {
+				if (*buff != '\0' 
+				&& !is_taggedcomment(buff, "Modified")) {
 					if (append_line(&inqueue, NULL, strdup(buff)))
 						goto cleanup;
 				}
@@ -1950,6 +2122,23 @@ conf_write(const char *filename, const char *section, const char *arg,
 		} while(err == 0);
 	}
 
+	if (modified_by) {
+		/* check for and update the Modified header */
+		/* does the file end in a blank line or a comment */
+		if (!TAILQ_EMPTY(&outqueue)) {
+			struct outbuffer *tail = TAILQ_LAST(&outqueue, tailhead);
+			if (tail && !is_empty(tail->text) && !is_comment(tail->text)) {
+				/* no, so add one for clarity */
+				if (append_line(&outqueue, NULL, strdup("\n")))
+					goto cleanup;
+			}
+		}
+
+		/* now append the modified date comment */
+		if (append_line(&outqueue, NULL, make_timestamp("Modified", now)))
+			goto cleanup;
+	}
+
 	/* now rewind and overwrite the file with the updated data */
 	rewind(infile);
 
diff --git a/tools/nfsconf/nfsconf.man b/tools/nfsconf/nfsconf.man
index 1ae8543..3079198 100644
--- a/tools/nfsconf/nfsconf.man
+++ b/tools/nfsconf/nfsconf.man
@@ -31,6 +31,8 @@ nfsconf \- Query various NFS configuration settings
 .P
 .B nfsconf \-\-set
 .RB [ \-v | \-\-verbose ]
+.RB [ \-m | \-\-modified
+.IR "Modified by text" ]
 .RB [ \-f | \-\-file
 .IR infile.conf ]
 .RB [ \-a | \-\-arg
@@ -61,7 +63,7 @@ Test if a specific tag has a value set.
 .IP "\fB\-g, \-\-get\fP"
 Output the current value of the specified tag.
 .IP "\fB\-s, \-\-set\fP"
-Update or Add a tag and value to the config file, creating the file if necessary.
+Update or Add a tag and value to the config file in a specified section, creating the tag, section, and file if necessary. If the section is defined as '#' then a comment is appended to the file. If a comment is set with a tag name then any exiting tagged comment with a matching name is replaced.
 .IP "\fB\-u, \-\-unset\fP"
 Remove the specified tag and its value from the config file.
 .SH OPTIONS
@@ -77,6 +79,9 @@ Select a different config file to operate upon, default is
 .TP
 .B \-a, \-\-arg \fIsubsection\fR
 Select a specific sub-section
+.SS Options only valid in \fB\-\-set\fR mode.
+.B \-m, \-\-modified \fI"Modified by nfsconf"\fR
+Set the text on the Modified date comment in the file. Set to empty to remove.
 .SH EXIT STATUS
 .SS \fB\-\-isset\fR mode
 In this mode the command will return success (0) if the selected tag has a value, any other exit code indicates the value is not set, or some other error has occurred.
diff --git a/tools/nfsconf/nfsconfcli.c b/tools/nfsconf/nfsconfcli.c
index f98d0d1..361d386 100644
--- a/tools/nfsconf/nfsconfcli.c
+++ b/tools/nfsconf/nfsconfcli.c
@@ -24,6 +24,7 @@ static void usage(const char *name)
 	fprintf(stderr, " -v			Increase Verbosity\n");
 	fprintf(stderr, " --file filename.conf	Load this config file\n");
 	fprintf(stderr, "     (Default config file: " NFS_CONFFILE "\n");
+	fprintf(stderr, " --modified \"info\"	Use \"info\" in file modified header\n");
 	fprintf(stderr, "Modes:\n");
 	fprintf(stderr, "  --dump [outputfile]\n");
 	fprintf(stderr, "      Outputs the configuration to the named file\n");
@@ -47,6 +48,8 @@ int main(int argc, char **argv)
 
 	confmode_t mode = MODE_NONE;
 
+	modified_by = "Modified by nfsconf";
+
 	while (1) {
 		int c;
 		int index = 0;
@@ -59,10 +62,11 @@ int main(int argc, char **argv)
 			{"dump",  optional_argument, 0, 'd' },
 			{"file",  required_argument, 0, 'f' },
 			{"verbose",	no_argument, 0, 'v' },
+			{"modified", required_argument, 0, 'm' },
 			{NULL,			  0, 0, 0 }
 		};
 
-		c = getopt_long(argc, argv, "gsua:id::f:v", long_options, &index);
+		c = getopt_long(argc, argv, "gsua:id::f:vm:", long_options, &index);
 		if (c == -1) break;
 
 		switch (c) {
@@ -99,6 +103,12 @@ int main(int argc, char **argv)
 				mode = MODE_DUMP;
 				dumpfile = optarg;
 				break;
+			case 'm':
+				if (optarg == NULL || *optarg == 0)
+					modified_by = NULL;
+				else
+					modified_by = optarg;
+				break;
 			default:
 				usage(argv[0]);
 				return 1;
-- 
1.8.3.1