1/*
2 * Copyright 2006 The Android Open Source Project
3 */
4
5#include <dirent.h>
6#include <sys/ptrace.h>
7#include <stdint.h>
8#include <thread_db.h>
9#include <stdlib.h>
10#include <stdio.h>
11
12extern int ps_pglobal_lookup (void *, const char *obj, const char *name, void **sym_addr);
13extern pid_t ps_getpid(struct ps_prochandle *ph);
14
15/*
16 * This is the list of "special" symbols we care about whose addresses are
17 * cached by gdbserver from the host at init time.
18 */
19enum {
20    SYM_TD_CREATE,
21    SYM_THREAD_LIST,
22    NUM_SYMS
23};
24
25static char const * gSymbols[] = {
26    [SYM_TD_CREATE] = "_thread_created_hook",
27    NULL
28};
29
30
31char const **
32td_symbol_list(void)
33{
34    return gSymbols;
35}
36
37
38td_err_e
39td_ta_new(struct ps_prochandle * proc_handle, td_thragent_t ** agent_out)
40{
41    td_thragent_t * agent;
42
43    agent = (td_thragent_t *)malloc(sizeof(td_thragent_t));
44    if (!agent) {
45        return TD_MALLOC;
46    }
47
48    agent->pid = ps_getpid(proc_handle);
49    agent->ph = proc_handle;
50    *agent_out = agent;
51
52    return TD_OK;
53}
54
55
56td_err_e
57td_ta_delete(td_thragent_t * ta)
58{
59    free(ta);
60    // FIXME: anything else to do?
61    return TD_OK;
62}
63
64
65/* NOTE: not used by gdb 7.0 */
66
67td_err_e
68td_ta_set_event(td_thragent_t const * agent, td_thr_events_t * events)
69{
70    return TD_OK;
71}
72
73
74/* NOTE: not used by gdb 7.0 */
75static td_thrhandle_t gEventMsgHandle;
76
77/* NOTE: not used by gdb 7.0 */
78
79static int
80_event_getmsg_helper(td_thrhandle_t const * handle, void * bkpt_addr)
81{
82    void * pc;
83
84#ifdef __i386__
85    /* Get the eip from offset 12*4 = 48 as defined in the struct
86     * user_regs_struct in user_32.h
87     */
88    pc = (void *)ptrace(PTRACE_PEEKUSR, handle->tid, (void *)48 /* eip */, NULL);
89    /* FIXME - pc is a non-decremented breakpoint address, hence the
90     * addition of 1 on test.  This seems to work for the thread hook
91     * function in libc.so but should be properly fixed.
92     */
93    if (pc == ((int)bkpt_addr + 1)) {
94        /* The hook function takes the id of the new thread as it's first
95         * param, so grab it from ecx at offset 4 in struct user_regs_struct
96         * (using fastcall convention for x86)
97         */
98        gEventMsgHandle.pid = ptrace(PTRACE_PEEKUSR, handle->tid, (void *)4 /* ecx */, NULL);
99        gEventMsgHandle.tid = gEventMsgHandle.pid;
100        return 0x42;
101    }
102#elif defined(__arm__)
103    pc = (void *)ptrace(PTRACE_PEEKUSR, handle->tid, (void *)60 /* r15/pc */, NULL);
104
105    if (pc == bkpt_addr) {
106        // The hook function takes the id of the new thread as it's first param,
107        // so grab it from r0.
108        gEventMsgHandle.pid = ptrace(PTRACE_PEEKUSR, handle->tid, (void *)0 /* r0 */, NULL);
109        gEventMsgHandle.tid = gEventMsgHandle.pid;
110        return 0x42;
111    }
112#elif defined(__mips__)
113    pc = (void *)ptrace(PTRACE_PEEKUSR, handle->tid, (void *)(64*4) /* pc */, NULL);
114    if (pc == bkpt_addr) {
115        // The hook function takes the id of the new thread as it's first param,
116        // so grab it from a0
117        gEventMsgHandle.pid = ptrace(PTRACE_PEEKUSR, handle->tid, (void *)(4*4) /* a0 */, NULL);
118        gEventMsgHandle.tid = gEventMsgHandle.pid;
119        return 0x42;
120    }
121#endif
122    return 0;
123}
124
125/* NOTE: not used by gdb 7.0 */
126
127td_err_e
128td_ta_event_getmsg(td_thragent_t const * agent, td_event_msg_t * event)
129{
130    td_err_e err;
131    void * bkpt_addr;
132
133    err = ps_pglobal_lookup(NULL, NULL, gSymbols[SYM_TD_CREATE], &bkpt_addr);
134    if (err) {
135        return err;
136    }
137
138    err = td_ta_thr_iter(agent, _event_getmsg_helper, bkpt_addr, 0, 0, NULL, 0);
139    if (err != 0x42) {
140        return TD_NOMSG;
141    }
142
143    event->event = TD_CREATE;
144    event->th_p = &gEventMsgHandle; // Nasty hack, but it's the only way!
145
146    return TD_OK;
147}
148
149
150td_err_e
151td_ta_map_lwp2thr(td_thragent_t const * agent, lwpid_t lwpid,
152		  td_thrhandle_t *th)
153{
154    th->pid = ps_getpid(agent->ph);
155    th->tid = lwpid;
156    return TD_OK;
157}
158
159
160td_err_e
161td_thr_get_info(td_thrhandle_t const * handle, td_thrinfo_t * info)
162{
163    info->ti_tid = handle->tid;
164    info->ti_lid = handle->tid;
165    info->ti_state = TD_THR_SLEEP; /* XXX this needs to be read from /proc/<pid>/task/<tid>.
166                                      This is only used to see if the thread is a zombie or not */
167    return TD_OK;
168}
169
170
171/* NOTE: not used by gdb 7.0 */
172
173td_err_e
174td_thr_event_enable(td_thrhandle_t const * handle, td_event_e event)
175{
176    // I don't think we need to do anything here...
177    return TD_OK;
178}
179
180
181/* NOTE: not used by gdb 7.0 */
182
183td_err_e
184td_ta_event_addr(td_thragent_t const * agent, td_event_e event, td_notify_t * notify_out)
185{
186    int32_t err;
187
188    /*
189     * This is nasty, ps_pglobal_lookup is implemented in gdbserver and looks up
190     * the symbol from it's cache, which is populated at start time with the
191     * symbols returned from td_symbol_list via calls back to the host.
192     */
193
194    switch (event) {
195        case TD_CREATE:
196            err = ps_pglobal_lookup(NULL, NULL, gSymbols[SYM_TD_CREATE], &notify_out->u.bptaddr);
197            if (err) {
198                return TD_NOEVENT;
199            }
200            return TD_OK;
201    }
202    return TD_NOEVENT;
203}
204
205
206td_err_e
207td_ta_clear_event(const td_thragent_t * ta_arg, td_thr_events_t * event)
208{
209    /* Given that gdb 7.0 doesn't use thread events,
210       there's nothing we need to do here.  */
211    return TD_OK;
212}
213
214
215td_err_e
216td_ta_thr_iter(td_thragent_t const * agent, td_thr_iter_f * func, void * cookie,
217               td_thr_state_e state, int32_t prio, sigset_t * sigmask, uint32_t user_flags)
218{
219    td_err_e err = TD_OK;
220    char path[32];
221    DIR * dir;
222    struct dirent * entry;
223    td_thrhandle_t handle;
224
225    snprintf(path, sizeof(path), "/proc/%d/task/", agent->pid);
226    dir = opendir(path);
227    if (!dir) {
228        return TD_NOEVENT;
229    }
230
231    handle.pid = agent->pid;
232    while ((entry = readdir(dir)) != NULL) {
233        if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0) {
234            continue;
235        }
236        handle.tid = atoi(entry->d_name);
237        if (func(&handle, cookie) != 0) {
238	    err = TD_DBERR;
239            break;
240        }
241    }
242
243    closedir(dir);
244
245    return err;
246}
247
248td_err_e
249td_thr_tls_get_addr(const td_thrhandle_t * th,
250		    psaddr_t map_address, size_t offset, psaddr_t * address)
251{
252    return TD_NOAPLIC; // FIXME: TODO
253}
254