src/osdep_linux.c

   1
   2 #include <sys/types.h>
   3 #include <sys/stat.h>
   4
   5 #include <errno.h>
   6 #include <fcntl.h>
   7 #include <limits.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 #include <WINGs/WUtil.h>
  13
  14 #include "wconfig.h"
  15 #include "osdep.h"
  16
  17
  18 /*
  19  * copy argc and argv for an existing process identified by `pid'
  20  * into suitable storage given in ***argv and *argc.
  21  *
  22  * subsequent calls use the same static area for argv and argc.
  23  *
  24  * returns 0 for failure, in which case argc := 0 and argv := NULL
  25  * returns 1 for success
  26  */
  27 Bool GetCommandForPid(int pid, char ***argv, int *argc)
  28 {
  29         static char buf[_POSIX_ARG_MAX];
  30         int fd, i, j;
  31         ssize_t count;
  32
  33         *argv = NULL;
  34         *argc = 0;
  35
  36         /* cmdline is a flattened series of null-terminated strings */
  37         snprintf(buf, sizeof(buf), "/proc/%d/cmdline", pid);
  38         while (1) {
  39                 /* not switching this to stdio yet, as this does not need
  40                  * to be portable, and i'm lazy */
  41                 fd = open(buf, O_RDONLY);
  42                 if (fd != -1)
  43                         break;
  44                 if (errno == EINTR)
  45                         continue;
  46                 return False;
  47         }
  48
  49         while (1) {
  50                 count = read(fd, buf, sizeof(buf));
  51                 if (count != -1)
  52                         break;
  53                 if (errno == EINTR)
  54                         continue;
  55                 close(fd);
  56                 return False;
  57         }
  58         close(fd);
  59
  60         /* count args */
  61         for (i = 0; i < count; i++)
  62                 if (buf[i] == '\0')
  63                         (*argc)++;
  64
  65         if (*argc == 0)
  66                 return False;
  67
  68         *argv = (char **)wmalloc(sizeof(char *) * (*argc + 1 /* term. null ptr */));
  69         (*argv)[0] = buf;
  70
  71         /* go through buf, set argv[$next] to the beginning of each string */
  72         for (i = 0, j = 1; i < count; i++) {
  73                 if (buf[i] != '\0')
  74                         continue;
  75                 if (i < count - 1)
  76                         (*argv)[j++] = &buf[i + 1];
  77                 if (j == *argc)
  78                         break;
  79         }
  80
  81         /* the list of arguments must be terminated by a null pointer */
  82         (*argv)[j] = NULL;
  83         return True;
  84 }