minix/usr.bin/trace/proc.c

   1
   2 #include "inc.h"
   3
   4 static TAILQ_HEAD(, trace_proc) proc_root;
   5 static unsigned int nr_procs;
   6
   7 /*
   8  * Initialize the list of traced processes.
   9  */
  10 void
  11 proc_init(void)
  12 {
  13
  14         TAILQ_INIT(&proc_root);
  15         nr_procs = 0;
  16 }
  17
  18 /*
  19  * Add a new process to the list of traced processes, allocating memory for it
  20  * first.  Return the new process structure with its PID assigned and the rest
  21  * zeroed out, or NULL upon allocation failure (with errno set appropriately).
  22  */
  23 struct trace_proc *
  24 proc_add(pid_t pid)
  25 {
  26         struct trace_proc *proc;
  27
  28         proc = (struct trace_proc *)malloc(sizeof(struct trace_proc));
  29
  30         if (proc == NULL)
  31                 return NULL;
  32
  33         memset(proc, 0, sizeof(*proc));
  34
  35         proc->pid = pid;
  36
  37         TAILQ_INSERT_TAIL(&proc_root, proc, next);
  38         nr_procs++;
  39
  40         return proc;
  41 }
  42
  43 /*
  44  * Retrieve the data structure for a traced process based on its PID.  Return
  45  * a pointer to the structure, or NULL if no structure exists for this process.
  46  */
  47 struct trace_proc *
  48 proc_get(pid_t pid)
  49 {
  50         struct trace_proc *proc;
  51
  52         /* Linear search for now; se we can easily add a hashtable later.. */
  53         TAILQ_FOREACH(proc, &proc_root, next) {
  54                 if (proc->pid == pid)
  55                         return proc;
  56         }
  57
  58         return NULL;
  59 }
  60
  61 /*
  62  * Remove a process from the list of traced processes.
  63  */
  64 void
  65 proc_del(struct trace_proc * proc)
  66 {
  67
  68         TAILQ_REMOVE(&proc_root, proc, next);
  69         nr_procs--;
  70
  71         free(proc);
  72 }
  73
  74 /*
  75  * Iterator for the list of traced processes.  If a NULL pointer is given,
  76  * return the first process in the list; otherwise, return the next process in
  77  * the list.  Not stable with respect to list modifications.
  78  */
  79 struct trace_proc *
  80 proc_next(struct trace_proc * proc)
  81 {
  82
  83         if (proc == NULL)
  84                 return TAILQ_FIRST(&proc_root);
  85         else
  86                 return TAILQ_NEXT(proc, next);
  87 }
  88
  89 /*
  90  * Return the number of processes in the list of traced processes.
  91  */
  92 unsigned int
  93 proc_count(void)
  94 {
  95
  96         return nr_procs;
  97 }