JehanneOS/mksh
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

• implement fcntl(2)-based advisory locking as an alternative iff flock(2)

Browse Source 
is not found, from a suggestion by RT (LP: #912691)
• try harder (in a loop) to acquire a file lock if the locking mechanism
  documents EINTR is a possibility (fcntl always, flock on Linux not .Ox)
• use -std=c99 not -std=gnu99 if it must be at all
This commit is contained in:
tg
2012-03-27 22:36:53 +00:00
parent e3b9f14d88
commit 95a2c63096
6 changed files with 106 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
histrap.c
View File

@@ -2,7 +2,8 @@
/* $OpenBSD: trap.c,v 1.23 2010/05/19 17:36:08 jasper Exp $ */
/*-
* Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
* Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
* 2011, 2012
* Thorsten Glaser <tg@mirbsd.org>
*
* Provided that these terms and disclaimer and all copyright notices
@@ -26,7 +27,7 @@
#include <sys/file.h>
#endif
__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.117 2011/12/31 00:47:45 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.118 2012/03/27 22:36:52 tg Exp $");
Trap sigtraps[NSIG + 1];
static struct sigaction Sigact_ign;
@@ -723,7 +724,7 @@ hist_init(Source *s)
if (histfd != fd)
close(fd);
(void)flock(histfd, LOCK_EX);
mksh_lockfd(histfd);
histfsize = lseek(histfd, (off_t)0, SEEK_END);
if (histfsize > MKSH_MAXHISTFSIZE || hs == hist_init_restore) {
@@ -815,7 +816,7 @@ hist_init(Source *s)
}
histfsize = lseek(histfd, (off_t)0, SEEK_END);
hist_init_tail:
(void)flock(histfd, LOCK_UN);
mksh_unlkfd(histfd);
#endif
}
@@ -880,7 +881,7 @@ writehistfile(int lno, const char *cmd)
size_t bytes;
unsigned char *base, *news;
(void)flock(histfd, LOCK_EX);
mksh_lockfd(histfd);
sizenow = lseek(histfd, (off_t)0, SEEK_END);
if (sizenow < histfsize) {
/* the file has shrunk; give up */
@@ -917,7 +918,7 @@ writehistfile(int lno, const char *cmd)
return;
}
histfsize = lseek(histfd, (off_t)0, SEEK_END);
(void)flock(histfd, LOCK_UN);
mksh_unlkfd(histfd);
}
static int
@@ -938,7 +939,7 @@ writehistline(int fd, int lno, const char *cmd)
void
hist_finish(void)
{
(void)flock(histfd, LOCK_UN);
mksh_unlkfd(histfd);
(void)close(histfd);
histfd = -1;
}
@@ -1419,3 +1420,53 @@ setexecsig(Trap *p, int restore)
break;
}
}
#if HAVE_PERSISTENT_HISTORY || defined(DF)
/*
* File descriptor locking and unlocking functions.
* Could use some error handling, but hey, this is only
* advisory locking anyway, will often not work over NFS,
* and you are SOL if this fails...
*/
void
mksh_lockfd(int fd)
{
#if defined(__OpenBSD__)
/* flock is not interrupted by signals */
(void)flock(fd, LOCK_EX);
#elif HAVE_FLOCK
int rv;
/* e.g. on Linux */
do {
rv = flock(fd, LOCK_EX);
} while (rv == 1 && errno == EINTR);
#elif HAVE_LOCK_FCNTL
int rv;
struct flock lks;
memset(&lks, 0, sizeof(lks));
lks.l_type = F_WRLCK;
do {
rv = fcntl(fd, F_SETLKW, &lks);
} while (rv == 1 && errno == EINTR);
#else
#error oops
#endif
}
void
mksh_unlkfd(int fd)
{
#if HAVE_FLOCK
(void)flock(fd, LOCK_UN);
#elif HAVE_LOCK_FCNTL
struct flock lks;
memset(&lks, 0, sizeof(lks));
lks.l_type = F_UNLCK;
(void)fcntl(fd, F_SETLKW, &lks);
#endif
}
#endif