This function duplicates and marks a file descriptor as close-on-exec.
Takes care of build and run-time support for the fcntl F_DUPFD_CLOEXEC
command, and other errors.
Signed-off-by: Guillem Jover <guillem@xxxxxxxxxxx>
---
include/fileutils.h | 1 +
lib/fileutils.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/include/fileutils.h b/include/fileutils.h
index 3353f69..e0e2ece 100644
--- a/include/fileutils.h
+++ b/include/fileutils.h
@@ -25,6 +25,7 @@ static inline FILE *xfmkstemp(char **tmpname, char *dir)
return ret;
}
+extern int dup_fd_cloexec(int oldfd, int lowfd);
extern int get_fd_tabsize(void);
extern int mkdir_p(const char *path, mode_t mode);
diff --git a/lib/fileutils.c b/lib/fileutils.c
index bffa8ff..81b38ad 100644
--- a/lib/fileutils.c
+++ b/lib/fileutils.c
@@ -50,6 +50,36 @@ int xmkstemp(char **tmpname, char *dir)
return fd;
}
+int dup_fd_cloexec(int oldfd, int lowfd)
+{
+ int fd, flags, errno_save;
+
+#ifdef F_DUPFD_CLOEXEC
+ fd = fcntl(oldfd, F_DUPFD_CLOEXEC, lowfd);
+ if (fd >= 0)
+ return fd;
+#endif
+
+ fd = dup(oldfd);
+ if (fd < 0)
+ return fd;
+
+ flags = fcntl(fd, F_GETFD);
+ if (flags < 0)
+ goto unwind;
+ if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0)
+ goto unwind;
+
+ return fd;
+
+unwind:
+ errno_save = errno;
+ close(fd);
+ errno = errno_save;
+
+ return -1;
+}
+
/*
* portable getdtablesize()
*/
--
2.2.1.209.g41e5f3a
--
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