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authorYiannis Marangos <yiannis.marangos@gmail.com>2014-04-10 21:54:12 +0300
committerJunio C Hamano <gitster@pobox.com>2014-04-10 12:18:55 -0700
commit9aa91af0361e3c32fde5f8388dee963838308cd6 (patch)
treee812122e47509cd50c380b77d2c44b304a1cc495 /wrapper.c
parent7bbc4e8fdb33e0a8e42e77cc05460d4c4f615f4d (diff)
downloadgit-9aa91af0361e3c32fde5f8388dee963838308cd6.tar.gz
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 <yiannis.marangos@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'wrapper.c')
-rw-r--r--wrapper.c18
1 files changed, 18 insertions, 0 deletions
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;