From 9aa91af0361e3c32fde5f8388dee963838308cd6 Mon Sep 17 00:00:00 2001 From: Yiannis Marangos Date: Thu, 10 Apr 2014 21:54:12 +0300 Subject: wrapper.c: add xpread() similar to xread() It is a common mistake to call read(2)/pread(2) and forget to anticipate that they may return error with EAGAIN/EINTR when the system call is interrupted. We have xread() helper to relieve callers of read(2) from having to worry about it; add xpread() helper to do the same for pread(2). Update the caller in the builtin/index-pack.c and the mmap emulation in compat/. Signed-off-by: Yiannis Marangos Signed-off-by: Junio C Hamano --- wrapper.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'wrapper.c') diff --git a/wrapper.c b/wrapper.c index 0cc56368bd..5b3c7fceb3 100644 --- a/wrapper.c +++ b/wrapper.c @@ -174,6 +174,24 @@ ssize_t xwrite(int fd, const void *buf, size_t len) } } +/* + * xpread() is the same as pread(), but it automatically restarts pread() + * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES + * NOT GUARANTEE that "len" bytes is read even if the data is available. + */ +ssize_t xpread(int fd, void *buf, size_t len, off_t offset) +{ + ssize_t nr; + if (len > MAX_IO_SIZE) + len = MAX_IO_SIZE; + while (1) { + nr = pread(fd, buf, len, offset); + if ((nr < 0) && (errno == EAGAIN || errno == EINTR)) + continue; + return nr; + } +} + ssize_t read_in_full(int fd, void *buf, size_t count) { char *p = buf; -- cgit v1.3-5-g9baa