Add support for tracing fork children

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 64 insertions, 0 deletions

diff --git a/process.c b/process.c
new file mode 100644
index 0000000..ea0dfd1
--- /dev/null
+++ b/process.c
@@ -0,0 +1,64 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+static struct process head;
+static struct process tail;
+
+
+void
+init_process_list(void)
+{
+        head.next = &tail;
+	tail.prev = &head;
+}
+
+
+struct process *
+find_process(pid_t pid)
+{
+        struct process *p;
+        for (p = head.next; p->next; p = p->next)
+                if (p->pid == pid)
+                        return p;
+        return NULL;
+}
+
+
+struct process *
+add_process(pid_t pid, int trace_options)
+{
+        struct process *proc;
+	int saved_errno;
+        proc = calloc(1, sizeof(*proc));
+	if (!proc)
+                eprintf("calloc: %s\n");
+        proc->pid = pid;
+	if (waitpid(pid, NULL, 0) < 0) {
+		eprintf("waitpid <child> NULL 0:");
+		kill(pid, SIGKILL);
+		exit(1);
+	}
+	if (ptrace(PTRACE_SETOPTIONS, pid, 0, trace_options)) {
+		saved_errno = errno;
+		kill(pid, SIGKILL);
+		errno = saved_errno;
+		eprintf("ptrace PTRACE_SETOPTIONS %ju 0 ...:", (uintmax_t)pid);
+	}
+        if (ptrace(PTRACE_SYSCALL, proc->pid, NULL, 0))
+                eprintf("ptrace PTRACE_SYSCALL %ju NULL 0:", (uintmax_t)pid);
+        proc->next = &tail;
+	proc->prev = tail.prev;
+	proc->prev->next = proc;
+	tail.prev = proc;
+	return proc;
+}
+
+
+void
+remove_process(struct process *proc)
+{
+ 	proc->prev->next = proc->next;
+	proc->next->prev = proc->prev;
+	free(proc);
+}