copy.c

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