ioexact.c

   1 #include <errno.h>
   2 #include <unistd.h>
   3 #include <signal.h>
   4 #include <stdbool.h>
   5
   6 #include "ioexact.h"
   7
   8 extern volatile sig_atomic_t sigint;
   9
  10 ssize_t read_exact(int fd, void *buf, size_t len, bool mayexit)
  11 {
  12         ssize_t num = 0, written;
  13
  14         while (len > 0 && !sigint) {
  15                 if ((written = read(fd, buf, len)) < 0) {
  16                         if (errno == EAGAIN && num > 0)
  17                                 continue;
  18                         if (mayexit)
  19                                 return -1;
  20                         else
  21                                 continue;
  22                 }
  23                 if (!written)
  24                         return 0;
  25
  26                 len -= written;
  27                 buf += written;
  28                 num += written;
  29         }
  30
  31         return num;
  32 }
  33
  34 ssize_t write_exact(int fd, void *buf, size_t len, bool mayexit)
  35 {
  36         ssize_t num = 0, written;
  37
  38         while (len > 0 && !sigint) {
  39                 if ((written = write(fd, buf, len)) < 0) {
  40                         if (errno == EAGAIN && num > 0)
  41                                 continue;
  42                         if (mayexit)
  43                                 return -1;
  44                         else
  45                                 continue;
  46                 }
  47                 if (!written)
  48                         return 0;
  49
  50                 len -= written;
  51                 buf += written;
  52                 num += written;
  53         }
  54
  55         return num;
  56 }