terminal info on AIX with /proc filesystem

Question

I am trying to get the terminal information with /proc file system on AIX.

Sample program on AIX

#include <stdio.h>

#include <sys/procfs.h>

#include <sys/sysmacros.h>


#define DEVNO64 0x8000000000000000LL

#define DEVNORSV 0x4000000000000000LL

#define DEV64_valid(_devno) \
        ((((((dev64_t)(_devno)) & (DEVNO64 | DEVNORSV)) >> 62) == 4) ? 1 : 0)

#define ISDEV_VALID(dev) DEV64_valid(dev)


int main(int argc, char *argv[])

{

      char      statfilenm[32];

      FILE     *fp;

      psinfo_t  pinfo;

      sprintf(statfilenm, "/proc/%d/psinfo", getpid());

      fp = fopen(statfilenm, "r");

      if (!fp)
        return 0;
      fread(&pinfo, sizeof(psinfo_t), 1, fp);
      fclose(fp);

      if(ISDEV_VALID((dev64_t)pinfo.pr_ttydev))
       printf("\n %d", minor64((dev64_t)pinfo.pr_ttydev));
      else
        printf("\n Invalid device");

}

Above program is returning "Invalid device" output for all processes with valid terminal also

Like

   PID    TTY STAT  TIME COMMAND
 10683272  pts/0 A     0:00 xxxxxxxxxxxxxxx

      PID    TTY STAT  TIME COMMAND
 10617844      - A     0:00  xxxxxxxxx

return value of fread is 1 which means it is reading 1 member of size(psinfo) — sunmoon, Aug 10 '21 at 12:10
What do you get if you print the actual value of `pinfo.pr_ttydev`, e.g. `printf("pr_ttydev %llx\n", (unsigned long long)pinfo.pr_ttydev);`? — Ian Abbott, Aug 10 '21 at 14:05

score 0 · Answer 1 · answered Aug 10 '21 at 15:06

If you wish to shift bit 2^63 into bit 2^2 then shift 61 times:

#define DEV64_valid(_devno) \
    ((((((dev64_t)(_devno)) & (DEVNO64 | DEVNORSV)) >> 61) == 4)

or alternatively:

#define DEV64_valid(_devno) \
    ((((((dev64_t)(_devno)) & (DEVNO64 | DEVNORSV)) >> 62) == 2)

terminal info on AIX with /proc filesystem

1 Answers1