1 /* The kernel call implemented in this file:
2 * m_type: SYS_TRACE
3 *
4 * The parameters for this kernel call are:
5 * m_lsys_krn_sys_trace.endpt process that is traced
6 * m_lsys_krn_sys_trace.request trace request
7 * m_lsys_krn_sys_trace.address address at traced process' space
8 * m_lsys_krn_sys_trace.data data to be written
9 * m_krn_lsys_sys_trace.data data to be returned
10 */
11
12 #include "kernel/system.h"
13 #include <sys/ptrace.h>
14
15 #if USE_TRACE
16
17 /*==========================================================================*
18 * do_trace *
19 *==========================================================================*/
do_trace(struct proc * caller,message * m_ptr)20 int do_trace(struct proc * caller, message * m_ptr)
21 {
22 /* Handle the debugging commands supported by the ptrace system call
23 * The commands are:
24 * T_STOP stop the process
25 * T_OK enable tracing by parent for this process
26 * T_GETINS return value from instruction space
27 * T_GETDATA return value from data space
28 * T_GETUSER return value from user process table
29 * T_SETINS set value in instruction space
30 * T_SETDATA set value in data space
31 * T_SETUSER set value in user process table
32 * T_RESUME resume execution
33 * T_EXIT exit
34 * T_STEP set trace bit
35 * T_SYSCALL trace system call
36 * T_ATTACH attach to an existing process
37 * T_DETACH detach from a traced process
38 * T_SETOPT set trace options
39 * T_GETRANGE get range of values
40 * T_SETRANGE set range of values
41 *
42 * The T_OK, T_ATTACH, T_EXIT, and T_SETOPT commands are handled completely by
43 * the process manager. T_GETRANGE and T_SETRANGE use sys_vircopy(). All others
44 * come here.
45 */
46
47 register struct proc *rp;
48 vir_bytes tr_addr = m_ptr->m_lsys_krn_sys_trace.address;
49 long tr_data = m_ptr->m_lsys_krn_sys_trace.data;
50 int tr_request = m_ptr->m_lsys_krn_sys_trace.request;
51 int tr_proc_nr_e = m_ptr->m_lsys_krn_sys_trace.endpt, tr_proc_nr;
52 unsigned char ub;
53 int i;
54
55 #define COPYTOPROC(addr, myaddr, length) { \
56 struct vir_addr fromaddr, toaddr; \
57 int r; \
58 fromaddr.proc_nr_e = KERNEL; \
59 toaddr.proc_nr_e = tr_proc_nr_e; \
60 fromaddr.offset = (myaddr); \
61 toaddr.offset = (addr); \
62 if((r=virtual_copy_vmcheck(caller, &fromaddr, \
63 &toaddr, length)) != OK) { \
64 printf("Can't copy in sys_trace: %d\n", r);\
65 return r;\
66 } \
67 }
68
69 #define COPYFROMPROC(addr, myaddr, length) { \
70 struct vir_addr fromaddr, toaddr; \
71 int r; \
72 fromaddr.proc_nr_e = tr_proc_nr_e; \
73 toaddr.proc_nr_e = KERNEL; \
74 fromaddr.offset = (addr); \
75 toaddr.offset = (myaddr); \
76 if((r=virtual_copy_vmcheck(caller, &fromaddr, \
77 &toaddr, length)) != OK) { \
78 printf("Can't copy in sys_trace: %d\n", r);\
79 return r;\
80 } \
81 }
82
83 if(!isokendpt(tr_proc_nr_e, &tr_proc_nr)) return(EINVAL);
84 if (iskerneln(tr_proc_nr)) return(EPERM);
85
86 rp = proc_addr(tr_proc_nr);
87 if (isemptyp(rp)) return(EINVAL);
88 switch (tr_request) {
89 case T_STOP: /* stop process */
90 RTS_SET(rp, RTS_P_STOP);
91 /* clear syscall trace and single step flags */
92 rp->p_misc_flags &= ~(MF_SC_TRACE | MF_STEP);
93 return(OK);
94
95 case T_GETINS: /* return value from instruction space */
96 COPYFROMPROC(tr_addr, (vir_bytes) &tr_data, sizeof(long));
97 m_ptr->m_krn_lsys_sys_trace.data = tr_data;
98 break;
99
100 case T_GETDATA: /* return value from data space */
101 COPYFROMPROC(tr_addr, (vir_bytes) &tr_data, sizeof(long));
102 m_ptr->m_krn_lsys_sys_trace.data= tr_data;
103 break;
104
105 case T_GETUSER: /* return value from process table */
106 if ((tr_addr & (sizeof(long) - 1)) != 0) return(EFAULT);
107
108 if (tr_addr <= sizeof(struct proc) - sizeof(long)) {
109 m_ptr->m_krn_lsys_sys_trace.data =
110 *(long *) ((char *) rp + (int) tr_addr);
111 break;
112 }
113
114 /* The process's proc struct is followed by its priv struct.
115 * The alignment here should be unnecessary, but better safe..
116 */
117 i = sizeof(long) - 1;
118 tr_addr -= (sizeof(struct proc) + i) & ~i;
119
120 if (tr_addr > sizeof(struct priv) - sizeof(long)) return(EFAULT);
121
122 m_ptr->m_krn_lsys_sys_trace.data =
123 *(long *) ((char *) rp->p_priv + (int) tr_addr);
124 break;
125
126 case T_SETINS: /* set value in instruction space */
127 COPYTOPROC(tr_addr, (vir_bytes) &tr_data, sizeof(long));
128 m_ptr->m_krn_lsys_sys_trace.data = 0;
129 break;
130
131 case T_SETDATA: /* set value in data space */
132 COPYTOPROC(tr_addr, (vir_bytes) &tr_data, sizeof(long));
133 m_ptr->m_krn_lsys_sys_trace.data = 0;
134 break;
135
136 case T_SETUSER: /* set value in process table */
137 if ((tr_addr & (sizeof(reg_t) - 1)) != 0 ||
138 tr_addr > sizeof(struct stackframe_s) - sizeof(reg_t))
139 return(EFAULT);
140 i = (int) tr_addr;
141 #if defined(__i386__)
142 /* Altering segment registers might crash the kernel when it
143 * tries to load them prior to restarting a process, so do
144 * not allow it.
145 */
146 if (i == (int) &((struct proc *) 0)->p_reg.cs ||
147 i == (int) &((struct proc *) 0)->p_reg.ds ||
148 i == (int) &((struct proc *) 0)->p_reg.es ||
149 i == (int) &((struct proc *) 0)->p_reg.gs ||
150 i == (int) &((struct proc *) 0)->p_reg.fs ||
151 i == (int) &((struct proc *) 0)->p_reg.ss)
152 return(EFAULT);
153
154 if (i == (int) &((struct proc *) 0)->p_reg.psw)
155 /* only selected bits are changeable */
156 SETPSW(rp, tr_data);
157 else
158 *(reg_t *) ((char *) &rp->p_reg + i) = (reg_t) tr_data;
159 #elif defined(__arm__)
160 if (i == (int) &((struct proc *) 0)->p_reg.psr) {
161 /* only selected bits are changeable */
162 SET_USR_PSR(rp, tr_data);
163 } else {
164 *(reg_t *) ((char *) &rp->p_reg + i) = (reg_t) tr_data;
165 }
166 #endif
167 m_ptr->m_krn_lsys_sys_trace.data = 0;
168 break;
169
170 case T_DETACH: /* detach tracer */
171 rp->p_misc_flags &= ~MF_SC_ACTIVE;
172
173 /* fall through */
174 case T_RESUME: /* resume execution */
175 RTS_UNSET(rp, RTS_P_STOP);
176 m_ptr->m_krn_lsys_sys_trace.data = 0;
177 break;
178
179 case T_STEP: /* set trace bit */
180 rp->p_misc_flags |= MF_STEP;
181 RTS_UNSET(rp, RTS_P_STOP);
182 m_ptr->m_krn_lsys_sys_trace.data = 0;
183 break;
184
185 case T_SYSCALL: /* trace system call */
186 rp->p_misc_flags |= MF_SC_TRACE;
187 RTS_UNSET(rp, RTS_P_STOP);
188 m_ptr->m_krn_lsys_sys_trace.data = 0;
189 break;
190
191 case T_READB_INS: /* get value from instruction space */
192 COPYFROMPROC(tr_addr, (vir_bytes) &ub, 1);
193 m_ptr->m_krn_lsys_sys_trace.data = ub;
194 break;
195
196 case T_WRITEB_INS: /* set value in instruction space */
197 ub = (unsigned char) (tr_data & 0xff);
198 COPYTOPROC(tr_addr, (vir_bytes) &ub, 1);
199 m_ptr->m_krn_lsys_sys_trace.data = 0;
200 break;
201
202 default:
203 return(EINVAL);
204 }
205 return(OK);
206 }
207
208 #endif /* USE_TRACE */
209