src/base/thread_lister.h

/* -*- Mode: c; c-basic-offset: 2; indent-tabs-mode: nil -*- */
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 * ---
 * Author: Markus Gutschke
 */

#ifndef _THREAD_LISTER_H
#define _THREAD_LISTER_H

#include <stdarg.h>
#include <sys/types.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef int (*ListAllProcessThreadsCallBack)(void *parameter,
                                             int num_threads,
                                             pid_t *thread_pids,
                                             va_list ap);

/* This function gets the list of all linux threads of the current process
 * passes them to the 'callback' along with the 'parameter' pointer; at the
 * call back call time all the threads are paused via
 * PTRACE_ATTACH.
 * The callback is executed from a separate thread which shares only the
 * address space, the filesystem, and the filehandles with the caller. Most
 * notably, it does not share the same pid and ppid; and if it terminates,
 * the rest of the application is still there. 'callback' is supposed to do
 * or arrange for TCMalloc_ResumeAllProcessThreads. This happens automatically, if
 * the thread raises a synchronous signal (e.g. SIGSEGV); asynchronous
 * signals are blocked. If the 'callback' decides to unblock them, it must
 * ensure that they cannot terminate the application, or that
 * TCMalloc_ResumeAllProcessThreads will get called.
 * It is an error for the 'callback' to make any library calls that could
 * acquire locks. Most notably, this means that most system calls have to
 * avoid going through libc. Also, this means that it is not legal to call
 * exit() or abort().
 * We return -1 on error and the return value of 'callback' on success.
 */
int TCMalloc_ListAllProcessThreads(void *parameter,
                                   ListAllProcessThreadsCallBack callback, ...);

/* This function resumes the list of all linux threads that
 * TCMalloc_ListAllProcessThreads pauses before giving to its
 * callback.  The function returns non-zero if at least one thread was
 * suspended and has now been resumed.
 */
int TCMalloc_ResumeAllProcessThreads(int num_threads, pid_t *thread_pids);

#ifdef __cplusplus
}
#endif

#endif  /* _THREAD_LISTER_H */