Message ID | 1396776553-7064-2-git-send-email-romain.naour@openwide.fr |
---|---|
State | Superseded |
Headers | show |
Dear Romain Naour, On Sun, 6 Apr 2014 11:29:13 +0200, Romain Naour wrote: > diff --git a/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch > new file mode 100644 > index 0000000..7b49d37 > --- /dev/null > +++ b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch > @@ -0,0 +1,29 @@ > +From d339af8fdc4b28175d6986d870f6735a9c2e90a3 Mon Sep 17 00:00:00 2001 > +From: Romain Naour <romain.naour@openwide.fr> > +Date: Sun, 6 Apr 2014 01:48:58 +0200 > +Subject: [PATCH 1/1] c.h: define mkostemp for uClibc > + > +uclibc does not implement mkostemp GNU extension > + > +Signed-off-by: Romain Naour <romain.naour@openwide.fr> > +--- > + include/c.h | 5 +++++ > + 1 file changed, 5 insertions(+) > + > +diff --git a/include/c.h b/include/c.h > +index 4a9bf3d..3ba51c1 100644 > +--- a/include/c.h > ++++ b/include/c.h > +@@ -300,4 +300,9 @@ static inline int usleep(useconds_t usec) > + # define SEEK_HOLE 4 > + #endif > + > ++#ifdef __UCLIBC__ > ++/* uclibc does not implement mkostemp GNU extension */ > ++#define mkostemp(x,y) mkstemp(x) > ++#endif Thanks for the patch. However, I believe there are two problems here: 1/ mkostemp() *can* exist with uClibc: the master branch of uClibc, which we use for some architectures (ARC and Xtensa) do have mkostemp(). Therefore, there should instead be a test in configure.ac like AC_CHECK_FUNCS([mkostemp]) and then make your code conditional on #ifndef HAVE_MKOSTEMP. 2/ The other problem is that in util-linux, mkostemp is used as follows: fd = mkostemp(n, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC); In your implementation, you discard the flags entirely, by using mkstemp(). mkstemp() will pass O_RDWR|O_CREAT|O_EXCL, but not O_CLOEXEC, which means that the file descriptor will no longer be closed automatically upon exec(). Though, looking at http://git.kernel.org/cgit/utils/util-linux/util-linux.git/commit/?id=b1fa3e2234fab95960eaa8499384000f189def13, they have switched to using O_CLOEXEC with no specific reason. Maybe I'm just worrying too much. But a solution might be to do something like: #ifndef HAVE_MKOSTEMP static inline int mkostemp(char *template, int flags) { int fd; fd = mkstemp(template); if (flags & O_CLOEXEC && fd >= 0) fcntl(fd, F_SETFD, FD_CLOEXEC); return fd; } #endif (Completely untested, not even compiled) Don't know if we want to worry about this though. Thomas
Hi Thomas, Le 06/04/2014 11:45, Thomas Petazzoni a écrit : > Dear Romain Naour, > > On Sun, 6 Apr 2014 11:29:13 +0200, Romain Naour wrote: > >> diff --git a/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch >> new file mode 100644 >> index 0000000..7b49d37 >> --- /dev/null >> +++ b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch >> @@ -0,0 +1,29 @@ >> +From d339af8fdc4b28175d6986d870f6735a9c2e90a3 Mon Sep 17 00:00:00 2001 >> +From: Romain Naour <romain.naour@openwide.fr> >> +Date: Sun, 6 Apr 2014 01:48:58 +0200 >> +Subject: [PATCH 1/1] c.h: define mkostemp for uClibc >> + >> +uclibc does not implement mkostemp GNU extension >> + >> +Signed-off-by: Romain Naour <romain.naour@openwide.fr> >> +--- >> + include/c.h | 5 +++++ >> + 1 file changed, 5 insertions(+) >> + >> +diff --git a/include/c.h b/include/c.h >> +index 4a9bf3d..3ba51c1 100644 >> +--- a/include/c.h >> ++++ b/include/c.h >> +@@ -300,4 +300,9 @@ static inline int usleep(useconds_t usec) >> + # define SEEK_HOLE 4 >> + #endif >> + >> ++#ifdef __UCLIBC__ >> ++/* uclibc does not implement mkostemp GNU extension */ >> ++#define mkostemp(x,y) mkstemp(x) >> ++#endif > Thanks for the patch. However, I believe there are two problems here: > > 1/ mkostemp() *can* exist with uClibc: the master branch of uClibc, > which we use for some architectures (ARC and Xtensa) do have > mkostemp(). Therefore, there should instead be a test in > configure.ac like AC_CHECK_FUNCS([mkostemp]) and then make your > code conditional on #ifndef HAVE_MKOSTEMP. Ok, I didn't notice that mkostemp() is available with latest uClibc, thanks. > > 2/ The other problem is that in util-linux, mkostemp is used as > follows: > > fd = mkostemp(n, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC); > > In your implementation, you discard the flags entirely, by using > mkstemp(). mkstemp() will pass O_RDWR|O_CREAT|O_EXCL, but not > O_CLOEXEC, which means that the file descriptor will no longer be > closed automatically upon exec(). Though, looking at > http://git.kernel.org/cgit/utils/util-linux/util-linux.git/commit/?id=b1fa3e2234fab95960eaa8499384000f189def13, > they have switched to using O_CLOEXEC with no specific reason. > Maybe I'm just worrying too much. But a solution might be to do > something like: > > #ifndef HAVE_MKOSTEMP > static inline int mkostemp(char *template, int flags) > { > int fd; > fd = mkstemp(template); > if (flags & O_CLOEXEC && fd >= 0) > fcntl(fd, F_SETFD, FD_CLOEXEC); > return fd; > } > #endif > > (Completely untested, not even compiled) > > Don't know if we want to worry about this though. > I had a build failure with the toolchain used by the autobuilder: ctng-i386-pentium4-uclibc.tar.bz2 That why I added this patch. Patch is on the way. Best regards, Romain
diff --git a/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch new file mode 100644 index 0000000..7b49d37 --- /dev/null +++ b/package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch @@ -0,0 +1,29 @@ +From d339af8fdc4b28175d6986d870f6735a9c2e90a3 Mon Sep 17 00:00:00 2001 +From: Romain Naour <romain.naour@openwide.fr> +Date: Sun, 6 Apr 2014 01:48:58 +0200 +Subject: [PATCH 1/1] c.h: define mkostemp for uClibc + +uclibc does not implement mkostemp GNU extension + +Signed-off-by: Romain Naour <romain.naour@openwide.fr> +--- + include/c.h | 5 +++++ + 1 file changed, 5 insertions(+) + +diff --git a/include/c.h b/include/c.h +index 4a9bf3d..3ba51c1 100644 +--- a/include/c.h ++++ b/include/c.h +@@ -300,4 +300,9 @@ static inline int usleep(useconds_t usec) + # define SEEK_HOLE 4 + #endif + ++#ifdef __UCLIBC__ ++/* uclibc does not implement mkostemp GNU extension */ ++#define mkostemp(x,y) mkstemp(x) ++#endif ++ + #endif /* UTIL_LINUX_C_H */ +-- +1.9.0 +
uclibc does not implement mkostemp GNU extension Signed-off-by: Romain Naour <romain.naour@openwide.fr> --- ...util-linux-004-define-mkostemp-for-uClibc.patch | 29 ++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 package/util-linux/util-linux-004-define-mkostemp-for-uClibc.patch