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 "funcs.h"
  16
  17
  18 #define RETRY( x )      do {                            \
  19                                 x;                      \
  20                         } while (errno == EINTR);
  21
  22 /*
  23  * copy argc and argv for an existing process identified by `pid'
  24  * into suitable storage given in ***argv and *argc.
  25  *
  26  * subsequent calls use the same static area for argv and argc.
  27  *
  28  * returns 0 for failure, in which case argc := 0 and argv := NULL
  29  * returns 1 for success
  30  */
  31 Bool GetCommandForPid(int pid, char ***argv, int *argc)
  32 {
  33         static char buf[_POSIX_ARG_MAX];
  34         int fd, i, j;
  35         ssize_t count;
  36
  37         *argv = NULL;
  38         *argc = 0;
  39
  40         /* cmdline is a flattened series of null-terminated strings */
  41         snprintf(buf, sizeof(buf), "/proc/%d/cmdline", pid);
  42         while (1) {
  43                 /* not switching this to stdio yet, as this does not need
  44                  * to be portable, and i'm lazy */
  45                 if ((fd = open(buf, O_RDONLY)) != -1)
  46                         break;
  47                 if (errno == EINTR)
  48                         continue;
  49                 return False;
  50         }
  51
  52         while (1) {
  53                 if ((count = read(fd, buf, sizeof(buf))) != -1)
  54                         break;
  55                 if (errno == EINTR)
  56                         continue;
  57                 RETRY( close(fd) )
  58                 return False;
  59         }
  60         RETRY( close(fd) )
  61
  62         /* count args */
  63         for (i = 0; i < count; i++)
  64                 if (buf[i] == '\0')
  65                         (*argc)++;
  66
  67         if (*argc == 0)
  68                 return False;
  69
  70         *argv = (char **)wmalloc(sizeof(char *) * (*argc + 1 /* term. null ptr */));
  71         (*argv)[0] = buf;
  72
  73         /* go through buf, set argv[$next] to the beginning of each string */
  74         for (i = 0, j = 1; i < count; i++) {
  75                 if (buf[i] != '\0')
  76                         continue;
  77                 if (i < count - 1)
  78                         (*argv)[j++] = &buf[i + 1];
  79                 if (j == *argc)
  80                         break;
  81         }
  82
  83         /* the list of arguments must be terminated by a null pointer */
  84         (*argv)[j] = NULL;
  85         return True;
  86 }