[git commit master 1/1] libc: Fix cancellation handling in some C functions
Salvatore Cro
salvatore.cro at st.com
Wed Sep 15 11:08:50 UTC 2010
commit: http://git.uclibc.org/uClibc/commit/?id=4b88e6e858b55def2ef0392278ddf81835f2ac45
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/master
According to POSIX.1-2008 standard, the following syscalls shall be
cancellation points : waitid, sleep, fdatasync, ppoll.
Further, if generic syscall is not available and stubs are
configured, provide the stub implementation for function.
Signed-off-by: Salvatore Cro <salvatore.cro at st.com>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso at st.com>
---
libc/sysdeps/linux/common/Makefile.in | 2 +-
libc/sysdeps/linux/common/fdatasync.c | 35 ++++++++++++++++++++++++++++++++-
libc/sysdeps/linux/common/ppoll.c | 15 +++++++++++++-
libc/sysdeps/linux/common/waitid.c | 27 +++++++++++++++++++++---
libc/unistd/sleep.c | 7 +++++-
5 files changed, 78 insertions(+), 8 deletions(-)
diff --git a/libc/sysdeps/linux/common/Makefile.in b/libc/sysdeps/linux/common/Makefile.in
index 4f0a72c..1711e80 100644
--- a/libc/sysdeps/linux/common/Makefile.in
+++ b/libc/sysdeps/linux/common/Makefile.in
@@ -27,7 +27,7 @@ endif
ifneq ($(UCLIBC_LINUX_SPECIFIC),y)
# we need these internally: fstatfs.c statfs.c
CSRC := $(filter-out capget.c capset.c inotify.c ioperm.c iopl.c madvise.c \
- modify_ldt.c personality.c prctl.c readahead.c reboot.c \
+ modify_ldt.c personality.c ppoll.c prctl.c readahead.c reboot.c \
remap_file_pages.c sched_getaffinity.c sched_setaffinity.c \
sendfile64.c sendfile.c setfsgid.c setfsuid.c setresuid.c \
splice.c vmsplice.c tee.c signalfd.c swapoff.c swapon.c \
diff --git a/libc/sysdeps/linux/common/fdatasync.c b/libc/sysdeps/linux/common/fdatasync.c
index a40f3e0..19d37b6 100644
--- a/libc/sysdeps/linux/common/fdatasync.c
+++ b/libc/sysdeps/linux/common/fdatasync.c
@@ -14,4 +14,37 @@
# define __NR_fdatasync __NR_osf_fdatasync
#endif
-_syscall1(int, fdatasync, int, fd)
+#ifdef __NR_fdatasync
+
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+# include <sysdep-cancel.h>
+# else
+# define SINGLE_THREAD_P 1
+# endif
+
+#define __NR___syscall_fdatasync __NR_fdatasync
+
+static __always_inline
+_syscall1(int, __syscall_fdatasync, int, fd)
+
+int fdatasync(int fd)
+{
+ if (SINGLE_THREAD_P)
+ return __syscall_fdatasync(fd);
+
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+ int oldtype = LIBC_CANCEL_ASYNC ();
+ int result = __syscall_fdatasync(fd);
+ LIBC_CANCEL_RESET (oldtype);
+ return result;
+# endif
+}
+
+#elif defined __UCLIBC_HAS_STUBS__
+/* no syscall available, so provide a stub */
+int fdatasync(int fd)
+{
+ __set_errno(ENOSYS);
+ return -1;
+}
+#endif
diff --git a/libc/sysdeps/linux/common/ppoll.c b/libc/sysdeps/linux/common/ppoll.c
index 02c8013..09b2b15 100644
--- a/libc/sysdeps/linux/common/ppoll.c
+++ b/libc/sysdeps/linux/common/ppoll.c
@@ -24,6 +24,12 @@
#include <stddef.h>
#if defined __NR_ppoll && defined __UCLIBC_LINUX_SPECIFIC__
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+# include <sysdep-cancel.h>
+# else
+# define SINGLE_THREAD_P 1
+# endif
+
int
ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
const sigset_t *sigmask)
@@ -35,8 +41,15 @@ ppoll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout,
tval = *timeout;
timeout = &tval;
}
+ if (SINGLE_THREAD_P)
+ return INLINE_SYSCALL(ppoll, 5, fds, nfds, timeout, sigmask, _NSIG / 8);
- return INLINE_SYSCALL(ppoll, 5, fds, nfds, timeout, sigmask, _NSIG / 8);
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+ int oldtype = LIBC_CANCEL_ASYNC ();
+ int result = INLINE_SYSCALL(ppoll, 5, fds, nfds, timeout, sigmask, _NSIG / 8);
+ LIBC_CANCEL_RESET (oldtype);
+ return result;
+# endif
}
libc_hidden_def(ppoll)
#endif
diff --git a/libc/sysdeps/linux/common/waitid.c b/libc/sysdeps/linux/common/waitid.c
index af55c91..c8115f9 100644
--- a/libc/sysdeps/linux/common/waitid.c
+++ b/libc/sysdeps/linux/common/waitid.c
@@ -14,20 +14,37 @@
# include <sys/syscall.h>
# ifdef __NR_waitid
+
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+# include <sysdep-cancel.h>
+# else
+# define SINGLE_THREAD_P 1
+# endif
+
/* The waitid() POSIX interface takes 4 arguments, but the kernel function
* actually takes 5. The fifth is a pointer to struct rusage. Make sure
* we pass NULL rather than letting whatever was in the register bleed up.
*/
#define __NR_waitid5 __NR_waitid
-static _syscall5(int, waitid5, idtype_t, idtype, id_t, id, siginfo_t*, infop,
+static __always_inline
+_syscall5(int, waitid5, idtype_t, idtype, id_t, id, siginfo_t*, infop,
int, options, struct rusage*, ru)
# endif
int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options)
{
# ifdef __NR_waitid
- return waitid5(idtype, id, infop, options, NULL);
-# else
+ if (SINGLE_THREAD_P)
+ return waitid5(idtype, id, infop, options, NULL);
+
+# ifdef __UCLIBC_HAS_THREADS_NATIVE__
+ int oldtype = LIBC_CANCEL_ASYNC ();
+ int result = waitid5(idtype, id, infop, options, NULL);
+ LIBC_CANCEL_RESET (oldtype);
+ return result;
+# endif
+
+# elif defined __NR_waitpid
switch (idtype) {
case P_PID:
if (id <= 0)
@@ -56,7 +73,9 @@ int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options)
if (infop->si_pid < 0)
return infop->si_pid;
return 0;
+# else
+ __set_errno(ENOSYS);
+ return -1;
# endif
}
-
#endif
diff --git a/libc/unistd/sleep.c b/libc/unistd/sleep.c
index 0c0416e..b0031f0 100644
--- a/libc/unistd/sleep.c
+++ b/libc/unistd/sleep.c
@@ -54,7 +54,12 @@ unsigned int sleep (unsigned int seconds)
/* This is not necessary but some buggy programs depend on this. */
if (seconds == 0)
- return 0;
+ {
+# ifdef CANCELLATION_P
+ CANCELLATION_P (THREAD_SELF);
+# endif
+ return 0;
+ }
/* Linux will wake up the system call, nanosleep, when SIGCHLD
arrives even if SIGCHLD is ignored. We have to deal with it
--
1.7.1
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