Re: [PATCH 2/2] mingw: ensure temporary file handles are not inherited by child processes
From: Eric Wong <hidden>
Date: 2016-08-19 01:21:58
Johannes Schindelin [off-list ref] wrote:
quoted hunk ↗ jump to hunk
+++ b/compat/mingw.h@@ -67,6 +67,10 @@ typedef int pid_t; #define F_SETFD 2 #define FD_CLOEXEC 0x1 +#if !defined O_CLOEXEC && defined O_NOINHERIT +#define O_CLOEXEC O_NOINHERIT +#endif
quoted hunk ↗ jump to hunk
+++ b/tempfile.c@@ -120,7 +120,7 @@ int create_tempfile(struct tempfile *tempfile, const char *path) prepare_tempfile_object(tempfile); strbuf_add_absolute_path(&tempfile->filename, path); - tempfile->fd = open(tempfile->filename.buf, O_RDWR | O_CREAT | O_EXCL, 0666); + tempfile->fd = open(tempfile->filename.buf, O_RDWR | O_CREAT | O_EXCL | O_CLOEXEC, 0666); if (tempfile->fd < 0) { strbuf_reset(&tempfile->filename); return -1;
O_CLOEXEC only exists since Linux 2.6.23 and there are likely
still LTS (CentOS 5.x?) and non-Linux systems which do not have
it, as well as machines with could have it defined in userspace
headers but not have it in the kernel.
So I suggest something like the following: (untested)
#define GIT_O_TMP (O_RDWR | O_CREAT | O_EXCL)
#ifndef O_CLOEXEC
# define O_CLOEXEC 0
#endif
/* state: -1=unknown; 0=broken; 1=working */
static int cloexec_state = O_CLOEXEC == 0 ? 0 : -1;
static int GIT_O_ETMP = (GIT_O_TMP | O_CLOEXEC)
int fd = open(filename, GIT_O_ETMP, 0666);
if (fd < 0 && errno == EINVAL && cloexec_state == -1 &&
GIT_O_ETMP != GIT_O_TMP) {
GIT_O_ETMP = GIT_O_TMP;
fd = open(filename, GIT_O_ETMP, 0666);
if (fd >= 0)
/* don't try O_CLOEXEC again */
cloexec_state = 0;
}
/*
* This is racy in the presence of threads,
* but the best we can do for old *nix:
*/
#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
if (fd >= 0 && cloexec_state != 1) {
int flags = fcntl(fd, F_GETFD);
if (flags == -1)
die_errno("F_GETFD failed");
if (flags & O_CLOEXEC)
cloexec_state = 1;
else {
flags = fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
if (flags == -1)
die_errno("F_SETFD failed");
cloexec_state = 0;
}
}
#endif
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