src/tools/btrfs_shell/command_cat.cpp

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 #include "syscalls.h"
   5 #include "system_dependencies.h"
   6
   7
   8 namespace FSShell {
   9
  10
  11 fssh_status_t
  12 command_cat(int argc, const char* const* argv)
  13 {
  14         long numBytes = 10;
  15         int fileStart = 1;
  16         if (argc < 2 || strcmp(argv[1], "--help") == 0) {
  17                 printf(
  18                         "Usage: %s [ -n ] [FILE]...\n"
  19                         "\t -n\tNumber of bytes to read\n",
  20                         argv[0]
  21                 );
  22                 return FSSH_B_OK;
  23         }
  24
  25         if (argc > 3 && strcmp(argv[1], "-n") == 0) {
  26                 fileStart += 2;
  27                 numBytes = strtol(argv[2], NULL, 10);
  28         }
  29
  30         const char* const* files = argv + fileStart;
  31         for (; *files; files++) {
  32                 const char* file = *files;
  33                 int fd = _kern_open(-1, file, O_RDONLY, O_RDONLY);
  34                 if (fd < 0) {
  35                         fssh_dprintf("Error: %s\n", fssh_strerror(fd));
  36                         return FSSH_B_BAD_VALUE;
  37                 }
  38
  39                 char buffer[numBytes + 1];
  40                 if (buffer == NULL) {
  41                         fssh_dprintf("Error: No memory\n");
  42                         _kern_close(fd);
  43                         return FSSH_B_NO_MEMORY;
  44                 }
  45
  46                 if (_kern_read(fd, 0, buffer, numBytes) != numBytes) {
  47                         fssh_dprintf("Error: fail to read, length: %i\n", numBytes);
  48                         _kern_close(fd);
  49                         return FSSH_B_BAD_VALUE;
  50                 }
  51
  52                 _kern_close(fd);
  53                 buffer[numBytes] = '\0';
  54                 printf("%s\n", buffer);
  55         }
  56
  57         return FSSH_B_OK;
  58 }
  59
  60
  61 }       // namespace FSShell