svn commit: r202177 - user/ed/utmpx/lib/libc/gen

[Ed Schouten]

Author: ed
Date: Tue Jan 12 22:06:53 2010
New Revision: 202177
URL: http://svn.freebsd.org/changeset/base/202177

Log:
  Several improvements to the handling of the utmpx files.
  
  - Just use O_EXLOCK instead of calling lockf() by hand. This will
    already provide exclusive file access.
  - Let the functions use stdio instead of operating on the file
    descriptors directly. When utmp and lastlogin files get a bit bigger,
    it will read chunks of 4K instead of 197 bytes at a time.

Modified:
  user/ed/utmpx/lib/libc/gen/pututxline.c

Modified: user/ed/utmpx/lib/libc/gen/pututxline.c
==============================================================================
--- user/ed/utmpx/lib/libc/gen/pututxline.c	Tue Jan 12 21:45:03 2010	(r202176)
+++ user/ed/utmpx/lib/libc/gen/pututxline.c	Tue Jan 12 22:06:53 2010	(r202177)
@@ -31,35 +31,43 @@ __FBSDID("$FreeBSD$");
 #include <sys/endian.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <utmpx.h>
 #include "utxdb.h"
 #include "un-namespace.h"
 
-static int
+static FILE *
 futx_open(const char *file)
 {
 	int fd;
+	FILE *fp;
 	struct stat sb;
 
-	fd = _open(file, O_CREAT|O_RDWR, 0644);
+	fd = _open(file, O_CREAT|O_RDWR|O_EXLOCK, 0644);
 	if (fd < 0)
-		return (-1);
+		return (NULL);
 
 	/* Safety check: never use broken files. */
 	if (_fstat(fd, &sb) != -1 && sb.st_size % sizeof(struct futx) != 0) {
 		_close(fd);
-		return (-1);
+		return (NULL);
+	}
+	
+	fp = fdopen(fd, "r+");
+	if (fp == NULL) {
+		_close(fd);
+		return (NULL);
 	}
 
-	return (fd);
+	return (fp);
 }
 
 static void
 utx_active_add(const struct futx *fu)
 {
-	int fd;
+	FILE *fp;
 	struct futx fe;
 	off_t partial = -1;
 
@@ -67,14 +75,10 @@ utx_active_add(const struct futx *fu)
 	 * Register user login sessions.  Overwrite entries of sessions
 	 * that have already been terminated.
 	 */
-	fd = futx_open(_PATH_UTX_ACTIVE);
-	if (fd < 0)
-		return;
-	if (lockf(fd, F_LOCK, 0) == -1) {
-		_close(fd);
+	fp = futx_open(_PATH_UTX_ACTIVE);
+	if (fp == NULL)
 		return;
-	}
-	while (_read(fd, &fe, sizeof fe) == sizeof fe) {
+	while (fread(&fe, sizeof fe, 1, fp) == 1) {
 		switch (fe.fu_type) {
 		case USER_PROCESS:
 		case INIT_PROCESS:
@@ -82,7 +86,7 @@ utx_active_add(const struct futx *fu)
 		case DEAD_PROCESS:
 			/* Overwrite when ut_id matches. */
 			if (memcmp(fu->fu_id, fe.fu_id, sizeof fe.fu_id) == 0) {
-				lseek(fd, -sizeof fe, SEEK_CUR);
+				fseeko(fp, -sizeof fe, SEEK_CUR);
 				goto exact;
 			}
 			if (fe.fu_type != DEAD_PROCESS)
@@ -91,7 +95,7 @@ utx_active_add(const struct futx *fu)
 		default:
 			/* Allow us to overwrite unused records. */
 			if (partial == -1)
-				partial = lseek(fd, 0, SEEK_CUR) - sizeof fe;
+				partial = fseeko(fp, 0, SEEK_CUR) - sizeof fe;
 			break;
 		}
 	}
@@ -101,29 +105,25 @@ utx_active_add(const struct futx *fu)
 	 * match was found, just append a new record.
 	 */
 	if (partial != -1)
-		lseek(fd, partial, SEEK_SET);
+		fseeko(fp, partial, SEEK_SET);
 exact:
-	_write(fd, fu, sizeof *fu);
-	_close(fd);
+	fwrite(fu, sizeof *fu, 1, fp);
+	fclose(fp);
 }
 
 static int
 utx_active_remove(struct futx *fu)
 {
-	int fd;
+	FILE *fp;
 	struct futx fe;
 
 	/*
 	 * Remove user login sessions, having the same ut_id.
 	 */
-	fd = futx_open(_PATH_UTX_ACTIVE);
-	if (fd < 0)
-		return (0);
-	if (lockf(fd, F_LOCK, 0) == -1) {
-		_close(fd);
+	fp = futx_open(_PATH_UTX_ACTIVE);
+	if (fp == NULL)
 		return (0);
-	}
-	while (_read(fd, &fe, sizeof fe) == sizeof fe) {
+	while (fread(&fe, sizeof fe, 1, fp) == 1) {
 		switch (fe.fu_type) {
 		case USER_PROCESS:
 		case INIT_PROCESS:
@@ -139,14 +139,14 @@ utx_active_remove(struct futx *fu)
 				fu->fu_tv = fe.fu_tv;
 
 			/* Terminate session. */
-			lseek(fd, -sizeof fe, SEEK_CUR);
-			_write(fd, fu, sizeof *fu);
-			_close(fd);
+			fseeko(fp, -sizeof fe, SEEK_CUR);
+			fwrite(fu, sizeof *fu, 1, fp);
+			fclose(fp);
 			return (0);
 		}
 	}
 
-	_close(fd);
+	fclose(fp);
 	return (1);
 }
 
@@ -160,7 +160,7 @@ utx_active_purge(void)
 static void
 utx_lastlogin_add(const struct futx *fu)
 {
-	int fd;
+	FILE *fp;
 	struct futx fe;
 
 	/*
@@ -168,14 +168,10 @@ utx_lastlogin_add(const struct futx *fu)
 	 * current user already has an entry.  If not, append a new
 	 * entry.
 	 */
-	fd = futx_open(_PATH_UTX_LASTLOGIN);
-	if (fd < 0)
-		return;
-	if (lockf(fd, F_LOCK, 0) == -1) {
-		_close(fd);
+	fp = futx_open(_PATH_UTX_LASTLOGIN);
+	if (fp == NULL)
 		return;
-	}
-	while (_read(fd, &fe, sizeof fe) == sizeof fe) {
+	while (fread(&fe, sizeof fe, 1, fp) == 1) {
 		if (strncmp(fu->fu_user, fe.fu_user, sizeof fe.fu_user) != 0)
 			continue;
 
@@ -184,12 +180,12 @@ utx_lastlogin_add(const struct futx *fu)
 			goto done;
 		
 		/* Found a previous lastlogin entry for this user. */
-		lseek(fd, -sizeof fe, SEEK_CUR);
+		fseeko(fp, -sizeof fe, SEEK_CUR);
 		break;
 	}
-	_write(fd, fu, sizeof *fu);
+	fwrite(fu, sizeof *fu, 1, fp);
 done:
-	_close(fd);
+	fclose(fp);
 }
 
 static void