From e00be2dcd02464a28d22bf84e345600ce1ea8cf6 Mon Sep 17 00:00:00 2001
From: Wilfried Goesgens <dothebart@citadel.org>
Date: Sat, 30 Oct 2010 18:44:15 +0200
Subject: [PATCH] * cmd_snet: make shure the target FS has enough space for the
 new config

 - Create our own filename insteaf of using mk*tmp*; CC->cs_pid should be uniq.; we use  O_CREAT|O_EXCL so we're shure its ours or fails.
 - Create that filename in the same directory as the filal config filename; by that we can be shure its in the same filesystem, and if thats full, we will fail
 - Stat the original file for sise (if not there assume 80) and write twice as much into that file so we're next to shure the content from the client will fit in
 - the citadel protocol is a little st00pit here, we don't know the size in advance, and we can't return an error _after_ accepting the file
 - instead of moving the content of the tempfile into the final file, we use rename() which is supposed to be atomic.
---
 citadel/modules/network/serv_network.c | 73 ++++++++++++++++++--------
 1 file changed, 51 insertions(+), 22 deletions(-)

diff --git a/citadel/modules/network/serv_network.c b/citadel/modules/network/serv_network.c
index c70929542..fdc37eede 100644
--- a/citadel/modules/network/serv_network.c
+++ b/citadel/modules/network/serv_network.c
@@ -403,8 +403,11 @@ void cmd_gnet(char *argbuf) {
 void cmd_snet(char *argbuf) {
 	char tempfilename[PATH_MAX];
 	char filename[PATH_MAX];
-	char buf[SIZ];
-	FILE *fp, *newfp;
+	int TmpFD;
+	StrBuf *Line;
+	struct stat StatBuf;
+	long len;
+	int rc;
 
 	unbuffer_output();
 
@@ -413,40 +416,66 @@ void cmd_snet(char *argbuf) {
 	}
 	else if (CtdlAccessCheck(ac_room_aide)) return;
 
-	CtdlMakeTempFileName(tempfilename, sizeof tempfilename);
-	assoc_file_name(filename, sizeof filename, &CC->room, ctdl_netcfg_dir);
+	len = assoc_file_name(filename, sizeof filename, &CC->room, ctdl_netcfg_dir);
+	memcpy(tempfilename, filename, len + 1);
 
-	fp = fopen(tempfilename, "w");
-	if (fp == NULL) {
-		cprintf("%d Cannot open %s: %s\n",
+	memset(&StatBuf, 0, sizeof(struct stat));
+	if (stat(filename, &StatBuf)  == -1)
+		StatBuf.st_size = 80; /* Not there? guess 80 chars line. */
+
+	sprintf(tempfilename + len, ".%d", CC->cs_pid);
+
+	TmpFD = open(tempfilename, O_CREAT|O_EXCL);
+
+	if (TmpFD > 0)
+	{
+		char *tmp = malloc(StatBuf.st_size * 2);
+		memset(tmp, 0, StatBuf.st_size * 2);
+		rc = write(TmpFD, tmp, StatBuf.st_size * 2);
+		free(tmp);
+		if (rc <= 0)
+		{
+			close(TmpFD);
+			cprintf("%d Unable to allocate the space required for %s: %s\n",
+				ERROR + INTERNAL_ERROR,
+				tempfilename,
+				strerror(errno));
+			return;
+		}	
+		lseek(TmpFD, SEEK_SET, 0);
+	}
+	else {
+		cprintf("%d Unable to allocate the space required for %s: %s\n",
 			ERROR + INTERNAL_ERROR,
 			tempfilename,
 			strerror(errno));
+
+
 	}
+	Line = NewStrBuf();
 
 	cprintf("%d %s\n", SEND_LISTING, tempfilename);
-	while (client_getln(buf, sizeof buf) >= 0 && strcmp(buf, "000")) {
-		fprintf(fp, "%s\n", buf);
+
+	len = 0;
+	while (rc = CtdlClientGetLine(Line), 
+	       (rc >= 0))
+	{
+		if ((rc == 3) && (strcmp(ChrPtr(Line), "000") == 0))
+			break;
+		StrBufAppendBufPlain(Line, HKEY("\n"), 0);
+		write(TmpFD, ChrPtr(Line), StrLength(Line));
+		len += StrLength(Line);
 	}
-	fclose(fp);
+	FreeStrBuf(&Line);
+	ftruncate(TmpFD, len + 1);
+	close(TmpFD);
 
 	/* Now copy the temp file to its permanent location.
 	 * (We copy instead of link because they may be on different filesystems)
 	 */
 	begin_critical_section(S_NETCONFIGS);
-	fp = fopen(tempfilename, "r");
-	if (fp != NULL) {
-		newfp = fopen(filename, "w");
-		if (newfp != NULL) {
-			while (fgets(buf, sizeof buf, fp) != NULL) {
-				fprintf(newfp, "%s", buf);
-			}
-			fclose(newfp);
-		}
-		fclose(fp);
-	}
+	rename(filename, tempfilename);
 	end_critical_section(S_NETCONFIGS);
-	unlink(tempfilename);
 }
 
 
-- 
2.39.2