src/osdep/darwin.c

   1
   2 #include <sys/types.h>
   3 #include <sys/sysctl.h>
   4
   5 #include <assert.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9 /*
  10  * copy argc and argv for an existing process identified by `pid'
  11  * into suitable storage given in ***argv and *argc.
  12  *
  13  * subsequent calls use the same static area for argv and argc.
  14  *
  15  * returns 0 for failure, in which case argc := 0 and argv := NULL
  16  * returns 1 for success
  17  */
  18 Bool GetCommandForPid(int pid, char ***argv, int *argc)
  19 #ifdef KERN_PROCARGS2
  20 {
  21         int j, mib[4];
  22         unsigned int i, idx;
  23         size_t count;
  24         static char *args = NULL;
  25         static int argmax = 0;
  26
  27         *argv = NULL;
  28         *argc = 0;
  29
  30         /* the system-wide limit */
  31         if (argmax == 0) { /* it hopefully doesn't change at runtime *g* */
  32                 mib[0] = CTL_KERN;
  33                 mib[1] = KERN_ARGMAX;
  34                 mib[2] = 0;
  35                 mib[3] = 0;
  36
  37                 count = sizeof(argmax);
  38                 if (sysctl(mib, 2, &argmax, &count, NULL, 0) == -1)
  39                         return False;
  40         }
  41
  42         /* if argmax is still 0, something went very seriously wrong */
  43         assert(argmax > 0);
  44
  45         /* space for args; no need to free before returning even on errors */
  46         if (args == NULL)
  47                 args = (char *)wmalloc(argmax);
  48
  49         /* get process args */
  50         mib[0] = CTL_KERN;
  51         mib[1] = KERN_PROCARGS2;
  52         mib[2] = pid;
  53
  54         count = argmax;
  55         if (sysctl(mib, 3, args, &count, NULL, 0) == -1 || count == 0)
  56                 return False;
  57
  58         /* get argc, skip */
  59         memcpy(argc, args, sizeof(*argc));
  60         idx = sizeof(*argc);
  61
  62         while (args[idx++] != '\0')             /* skip execname */
  63                 ;
  64         while (args[idx] == '\0')               /* padding too */
  65                 idx++;
  66         /* args[idx] is at at begininng of args now */
  67
  68         *argv = (char **)wmalloc(sizeof(char *) * (*argc + 1 /* term. null ptr */));
  69         (*argv)[0] = args + idx;
  70
  71         /* go through args, set argv[$next] to the beginning of each string */
  72         for (i = 0, j = 1; i < count - idx /* do not overrun */; i++) {
  73                 if (args[idx + i] != '\0')
  74                         continue;
  75                 if (args[idx + i] == '\0')
  76                         (*argv)[j++] = &args[idx + 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 }
  85 #else /* !KERN_PROCARGS2 */
  86 {
  87         *argv = NULL;
  88         *argc = 0;
  89
  90         return False;
  91 }
  92 #endif