util.c

   1 #include <errno.h>
   2 #include <fcntl.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <sys/wait.h>
   8 #include "util.h"
   9
  10 int file_size(int fd)
  11 {
  12         struct stat stat;
  13         fstat(fd, &stat);
  14         return stat.st_size;
  15 }
  16
  17 int xread(int fd, char *buf, int len)
  18 {
  19         int nr = 0;
  20         while (nr < len) {
  21                 int ret = read(fd, buf + nr, len - nr);
  22                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
  23                         continue;
  24                 if (ret <= 0)
  25                         break;
  26                 nr += ret;
  27         }
  28         return nr;
  29 }
  30
  31 int xwrite(int fd, char *buf, int len)
  32 {
  33         int nw = 0;
  34         while (nw < len) {
  35                 int ret = write(fd, buf + nw, len - nw);
  36                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
  37                         continue;
  38                 if (ret < 0)
  39                         break;
  40                 nw += ret;
  41         }
  42         return nw;
  43 }
  44
  45 void exec_file(char *filename, char **args)
  46 {
  47         pid_t pid;
  48         if (!(pid = fork())) {
  49                 execvp(filename, args);
  50                 exit(1);
  51         }
  52         waitpid(pid, NULL, 0);
  53 }
  54
  55 void exec_pipe(char *file, char **argv, char *s, int len)
  56 {
  57         pid_t pid;
  58         int fds[2];
  59         pipe(fds);
  60         if (!(pid = fork())) {
  61                 close(fds[1]);
  62                 dup2(fds[0], STDIN_FILENO);
  63                 execvp(file, argv);
  64                 exit(1);
  65         }
  66         close(fds[0]);
  67         write(fds[1], s, len);
  68         close(fds[1]);
  69         waitpid(pid, NULL, 0);
  70 }