git-svn: extra error check to ensure we open a file correctly
[git] / copy.c
1 #include "cache.h"
2
3 int copy_fd(int ifd, int ofd)
4 {
5         while (1) {
6                 int len;
7                 char buffer[8192];
8                 char *buf = buffer;
9                 len = xread(ifd, buffer, sizeof(buffer));
10                 if (!len)
11                         break;
12                 if (len < 0) {
13                         int read_error;
14                         read_error = errno;
15                         close(ifd);
16                         return error("copy-fd: read returned %s",
17                                      strerror(read_error));
18                 }
19                 while (len) {
20                         int written = xwrite(ofd, buf, len);
21                         if (written > 0) {
22                                 buf += written;
23                                 len -= written;
24                         }
25                         else if (!written) {
26                                 close(ifd);
27                                 return error("copy-fd: write returned 0");
28                         } else {
29                                 close(ifd);
30                                 return error("copy-fd: write returned %s",
31                                              strerror(errno));
32                         }
33                 }
34         }
35         close(ifd);
36         return 0;
37 }
38