diff options
author | Corinna Vinschen <corinna@vinschen.de> | 2003-12-07 15:56:59 +0300 |
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committer | Corinna Vinschen <corinna@vinschen.de> | 2003-12-07 15:56:59 +0300 |
commit | 2e3ff06d3c0424e2862afba051c4928d268a21c7 (patch) | |
tree | 5076533162a573821fbdd9020c134ebda2008663 /winsup | |
parent | ae2543ed76f3271061bffc0549961aa74baba64f (diff) |
* syscalls.cc (locked_append): New.
(updwtmp): Remove mutex code and call locked_append.
(pututline): Ditto.
Diffstat (limited to 'winsup')
-rw-r--r-- | winsup/cygwin/ChangeLog | 6 | ||||
-rw-r--r-- | winsup/cygwin/syscalls.cc | 57 |
2 files changed, 34 insertions, 29 deletions
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index 4da0b4167..3aa4c1b21 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,3 +1,9 @@ +2003-12-07 Pierre Humblet <pierre.humblet@ieee.org> + + * syscalls.cc (locked_append): New. + (updwtmp): Remove mutex code and call locked_append. + (pututline): Ditto. + 2003-12-06 Christopher Faylor <cgf@redhat.com> * exceptions.cc (_threadinfo::remove): Avoid a linked list walk. diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc index 06cffa0b6..f45308bb0 100644 --- a/winsup/cygwin/syscalls.cc +++ b/winsup/cygwin/syscalls.cc @@ -2553,28 +2553,37 @@ ffs (int i) return table[x >> a] + a; } +static void +locked_append (int fd, const void * buf, size_t size) +{ + struct __flock64 lock_buffer = {F_WRLCK, SEEK_SET, 0, 0, 0}; + int count = 0; + + do + if ((lock_buffer.l_start = lseek64 (fd, 0, SEEK_END)) != (_off64_t)-1 + && fcntl_worker (fd, F_SETLKW, &lock_buffer) != -1) + { + if (lseek64 (fd, 0, SEEK_END) != (_off64_t)-1) + write (fd, buf, size); + lock_buffer.l_type = F_UNLCK; + fcntl_worker (fd, F_SETLK, &lock_buffer); + break; + } + while (count++ < 1000 + && (errno == EACCES || errno == EAGAIN) + && !usleep (1000)); +} + extern "C" void updwtmp (const char *wtmp_file, const struct utmp *ut) { - /* Writing to wtmp must be atomic to prevent mixed up data. */ - char mutex_name[CYG_MAX_PATH]; - HANDLE mutex; int fd; - mutex = CreateMutex (NULL, FALSE, shared_name (mutex_name, "wtmp_mutex", 0)); - if (mutex) - while (WaitForSingleObject (mutex, INFINITE) == WAIT_ABANDONED) - ; - if ((fd = open (wtmp_file, O_WRONLY | O_APPEND | O_BINARY, 0)) >= 0) + if ((fd = open (wtmp_file, O_WRONLY | O_BINARY, 0)) >= 0) { - write (fd, ut, sizeof *ut); + locked_append (fd, ut, sizeof *ut); close (fd); } - if (mutex) - { - ReleaseMutex (mutex); - CloseHandle (mutex); - } } extern "C" void @@ -2783,25 +2792,15 @@ pututline (struct utmp *ut) ut->ut_type, ut->ut_pid, ut->ut_line, ut->ut_id); debug_printf ("ut->ut_user '%s', ut->ut_host '%s'\n", ut->ut_user, ut->ut_host); - /* Read/write to utmp must be atomic to prevent overriding data - by concurrent processes. */ - char mutex_name[CYG_MAX_PATH]; - HANDLE mutex = CreateMutex (NULL, FALSE, - shared_name (mutex_name, "utmp_mutex", 0)); - if (mutex) - while (WaitForSingleObject (mutex, INFINITE) == WAIT_ABANDONED) - ; + struct utmp *u; if ((u = getutid (ut))) - lseek (utmp_fd, -sizeof *ut, SEEK_CUR); - else - lseek (utmp_fd, 0, SEEK_END); - write (utmp_fd, ut, sizeof *ut); - if (mutex) { - ReleaseMutex (mutex); - CloseHandle (mutex); + lseek (utmp_fd, -sizeof *ut, SEEK_CUR); + write (utmp_fd, ut, sizeof *ut); } + else + locked_append (utmp_fd, ut, sizeof *ut); } extern "C" |