/*

   +----------------------------------------------------------------------+

   | Zend Engine                                                          |

   +----------------------------------------------------------------------+

   | Copyright © Zend Technologies Ltd., a subsidiary company of          |

   |     Perforce Software, Inc., and Contributors.                       |

   +----------------------------------------------------------------------+

   | This source file is subject to the Modified BSD License that is      |

   | bundled with this package in the file LICENSE, and is available      |

   | through the World Wide Web at <https://www.php.net/license/>.        |

   |                                                                      |

   | SPDX-License-Identifier: BSD-3-Clause                                |

   +----------------------------------------------------------------------+

   | Authors: Dmitry Stogov <dmitry@zend.com>                             |

   |          Xinchen Hui <xinchen.h@zend.com>                            |

   +----------------------------------------------------------------------+

*/

#include "zend.h"

#include "zend_gdb.h"

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#if defined(__FreeBSD__) && __FreeBSD_version >= 1100000

# include <sys/user.h>

# include <libutil.h>

#endif

enum {

  ZEND_GDBJIT_NOACTION,

  ZEND_GDBJIT_REGISTER,

  ZEND_GDBJIT_UNREGISTER

};

typedef struct _zend_gdbjit_code_entry {

  struct _zend_gdbjit_code_entry *next_entry;

  struct _zend_gdbjit_code_entry *prev_entry;

  const char                     *symfile_addr;

  uint64_t                        symfile_size;

} zend_gdbjit_code_entry;

typedef struct _zend_gdbjit_descriptor {

  uint32_t                         version;

  uint32_t                         action_flag;

  struct _zend_gdbjit_code_entry *relevant_entry;

  struct _zend_gdbjit_code_entry *first_entry;

} zend_gdbjit_descriptor;

ZEND_API zend_gdbjit_descriptor __jit_debug_descriptor = {

  1, ZEND_GDBJIT_NOACTION, NULL, NULL

};

ZEND_API zend_never_inline void __jit_debug_register_code(void)

{

  __asm__ __volatile__("");

}

ZEND_API bool zend_gdb_register_code(const void *object, size_t size)

{

  zend_gdbjit_code_entry *entry;

  entry = malloc(sizeof(zend_gdbjit_code_entry) + size);

  if (entry == NULL) {

    return 0;

  }

  entry->symfile_addr = ((char*)entry) + sizeof(zend_gdbjit_code_entry);

  entry->symfile_size = size;

  memcpy((char *)entry->symfile_addr, object, size);

  entry->prev_entry = NULL;

  entry->next_entry = __jit_debug_descriptor.first_entry;

  if (entry->next_entry) {

    entry->next_entry->prev_entry = entry;

  }

  __jit_debug_descriptor.first_entry = entry;

  /* Notify GDB */

  __jit_debug_descriptor.relevant_entry = entry;

  __jit_debug_descriptor.action_flag = ZEND_GDBJIT_REGISTER;

  __jit_debug_register_code();

  return 1;

}

ZEND_API void zend_gdb_unregister_all(void)

{

  zend_gdbjit_code_entry *entry;

  __jit_debug_descriptor.action_flag = ZEND_GDBJIT_UNREGISTER;

  while ((entry = __jit_debug_descriptor.first_entry)) {

    __jit_debug_descriptor.first_entry = entry->next_entry;

    if (entry->next_entry) {

      entry->next_entry->prev_entry = NULL;

    }

    /* Notify GDB */

    __jit_debug_descriptor.relevant_entry = entry;

    __jit_debug_register_code();

    free(entry);

  }

}

ZEND_API bool zend_gdb_present(void)

{

  bool ret = false;

#if defined(__linux__) /* netbsd while having this procfs part, does not hold the tracer pid */

  int fd = open("/proc/self/status", O_RDONLY);

  if (fd >= 0) {

    char buf[1024];

    ssize_t n = read(fd, buf, sizeof(buf) - 1);

    char *s;

    pid_t pid;

    if (n > 0) {

      buf[n] = 0;

      s = strstr(buf, "TracerPid:");

      if (s) {

        s += sizeof("TracerPid:") - 1;

        while (*s == ' ' || *s == '\t') {

          s++;

        }

        pid = atoi(s);

        if (pid) {

          char out[1024];

          snprintf(buf, sizeof(buf), "/proc/%d/exe", (int)pid);

          if (readlink(buf, out, sizeof(out) - 1) > 0) {

            if (strstr(out, "gdb")) {

              ret = true;

            }

          }

        }

      }

    }

    close(fd);

  }

#elif defined(__FreeBSD__) && __FreeBSD_version >= 1100000

    struct kinfo_proc *proc = kinfo_getproc(getpid());

    if (proc) {

        if ((proc->ki_flag & P_TRACED) != 0) {

            struct kinfo_proc *dbg = kinfo_getproc(proc->ki_tracer);

            ret = (dbg && strstr(dbg->ki_comm, "gdb"));

        }

    }

#endif

  return ret;

}