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12 .\" Copyright 2015 Joyent, Inc.
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14 .Dd May 11, 2016
15 .Dt PSYMBOL_ITER 3PROC
16 .Os
17 .Sh NAME
18 .Nm Psymbol_iter ,
19 .Nm Psymbol_iter_by_addr ,
20 .Nm Psymbol_iter_by_lmid ,
21 .Nm Psymbol_iter_by_name ,
22 .Nm Pxsymbol_iter
23 .Nd iterate symbols in a process
24 .Sh SYNOPSIS
25 .Lb libproc
26 .In libproc.h
27 .Ft int
28 .Fo Psymbol_iter
29 .Fa "struct ps_prochandle *P"
30 .Fa "const char *object_name"
31 .Fa "int which"
32 .Fa "int mask"
33 .Fa "proc_sym_f *func"
34 .Fa "void *data"
35 .Fc
36 .Ft int
37 .Fo Psymbol_iter_by_addr
38 .Fa "struct ps_prochandle *P"
39 .Fa "const char *object_name"
40 .Fa "int which"
41 .Fa "int mask"
42 .Fa "proc_sym_f *func"
43 .Fa "void *data"
44 .Fc
45 .Ft int
46 .Fo Psymbol_iter_by_lmid
47 .Fa "struct ps_prochandle *P"
48 .Fa "Lmid_t lmid"
49 .Fa "const char *object_name"
50 .Fa "int which"
51 .Fa "int mask"
52 .Fa "proc_sym_f *func"
53 .Fa "void *data"
54 .Fc
55 .Ft int
56 .Fo Psymbol_iter_by_name
57 .Fa "struct ps_prochandle *P"
58 .Fa "const char *object_name"
59 .Fa "int which"
60 .Fa "int mask"
61 .Fa "proc_sym_f *func"
62 .Fa "void *data"
63 .Fc
64 .Ft int
65 .Fo Pxsymbol_iter
66 .Fa "struct ps_prochandle *P"
67 .Fa "Lmid_t lmid"
68 .Fa "const char *object_name"
69 .Fa "int which"
70 .Fa "int mask"
71 .Fa "proc_xsym_f *func"
72 .Fa "void *data"
73 .Fc
74 .Sh DESCRIPTION
75 The
76 .Fn Psymbol_iter ,
77 .Fn Psymbol_iter_by_addr ,
78 .Fn Psymbol_iter_by_lmid ,
79 .Fn Psymbol_iter_by_name ,
80 and
81 .Fn Pxsymbol_iter
82 functions are used to iterate over the symbols present in the process
83 referred to by the handle
84 .Fa P .
85 For each symbol found, the callback function
86 .Fa func
87 will be called once and the argument
88 .Fa data
89 will be passed to it along with an ELF symbol entry in the form of the
90 .Sy GElf_Sym
91 along with the name of the symbol, if known.
92 In the case of the
93 .Fn Pxsymbol_iter
94 function an additional
95 .Sy prsyminfo_t
96 argument will be provided to the callback.
97 The definitions of
98 .Sy proc_sym_f ,
99 .Sy proc_xsym_f ,
100 and
101 .Sy prsyminfo_t
102 are found in
103 .Xr libproc 3LIB .
104 .Pp
105 The
106 .Fa object_name
107 argument names the object that is a part of the controlled process which
108 will be searched for symbols.
109 Only one object may be searched at any given time.
110 Valid object names may be obtained through the
111 .Xr Pobjname 3PROC
112 and
113 .Xr Pobject_iter 3PROC
114 functions, among others.
115 The system also has two special object names that may be passed in to refer to
116 the objects of the executable file and for ld.so.1.
117 The symbol
118 .Dv PR_OBJ_EXEC
119 refers to the executables object and the symbol
120 .Dv PR_OBJ_LDSO
121 refers to the object ld.so.1.
122 .Pp
123 The
124 .Fa which
125 argument controls which of two possible symbol tables will be searched.
126 If the argument is
127 .Dv PR_SYMTAB
128 then the ELF symbol table will be searched.
129 Otherwise, if it is
130 .Dv PR_DYNSYM
131 then the symbol table associated with the dynamic section will be
132 searched instead.
133 If any other value is specified for
134 .Fa which ,
135 then an error will be returned.
136 .Pp
137 The
138 .Fa mask
139 argument controls which symbols will be included.
140 The
141 .Fa mask
142 argument allows for control over both the symbol's binding and the
143 symbol's type.
144 These flags logically correspond to the various ELF symbol bindings and types.
145 The following values may be passed as a bitwise-inclusive-OR into the
146 .Fa flags
147 argument:
148 .Bl -tag -width Dv -offset indent
149 .It Dv BIND_LOCAL
150 The symbol is a local symbol.
151 Local symbols are not visible outside of their object file.
152 .It Dv BIND_GLOBAL
153 The symbol is a global symbol.
154 Global symbols are visible outside of their object file and may be referred to
155 by other ELF objects.
156 .It Dv BIND_WEAK
157 The symbol is a weak symbol.
158 Weak symbols are visible outside of their object file, but another definition of
159 the symbol may be used instead.
160 .It Dv BIND_ANY
161 This is a combination of
162 .Dv BIND_LOCAL ,
163 .Dv BIND_GLOBAL ,
164 and
165 .Dv BIND_WEAK .
166 Every symbol's binding will match this value.
167 .It Dv TYPE_NOTYPE
168 The symbol's type is not specified.
169 .It Dv TYPE_OBJECT
170 The symbol refers to a data object.
171 For example, variables.
172 .It Dv TYPE_FUNC
173 The symbol refers to a function.
174 .It Dv TYPE_SECTION
175 The symbol refers to an ELF section.
176 .It Dv TYPE_FILE
177 The symbol refers to the name of a source file associated with an object
178 file.
179 .It Dv TYPE_ANY
180 This is a combination of
181 .Dv TYPE_NOTYPE ,
182 .Dv TYPE_OBJECT ,
183 .Dv TYPE_FUNC ,
184 .Dv TYPE_SECTION ,
185 and
186 .Dv TYPE_FILE .
187 Every symbol's type will match this value.
188 .El
189 .Pp
190 To obtain all of the symbols in an object, the caller would pass the
191 expression
192 .Dv BIND_ANY |
193 .Dv TYPE_ANY
194 in as the value of
195 .Fa mask.
196 .Pp
197 The
198 .Fn Psymbol_iter_by_lmid
199 and
200 .Fn Pxsymbol_iter
201 functions allow for a link-map identifier to be specified in the
202 .Fa lmid
203 argument.
204 This will restrict the search for the object specified in
205 .Fa object_name
206 to the specified link-map.
207 There are three special link-map identifiers that may be passed in.
208 The symbol
209 .Dv PR_LMID_EVERY
210 indicates that every link-map should be searched.
211 The symbol
212 .Dv LM_ID_BASE
213 indicates that the base link-map, the one that is used for the
214 executable should be searched.
215 Finally, the symbol
216 .Dv LM_ID_LDSO
217 refers to the link-map that is used by the run-time link editor, ld.so.1.
218 The functions which do not allow a link-map identifier to be specified always
219 search every link-map.
220 .Pp
221 By default, symbols are iterated based on the order of the symbol
222 table being searched.
223 However, it is also possible to iterate based on the name of the symbol and
224 based on the address of the symbol.
225 To iterate by name use the
226 .Fn Psymbol_iter_by_name
227 function.
228 To iterate by address use the
229 .Fn Psymbol_iter_by_addr
230 function.
231 The
232 .Fn Psymbol_iter ,
233 .Fn Psymbol_iter_by_lmid ,
234 and
235 .Fn Pxsymbol_iter
236 functions all sort based on the order of the symbol table.
237 .Pp
238 The return value of the callback function
239 .Fa func
240 determines whether or not iteration continues.
241 If
242 .Fa func
243 returns
244 .Sy 0,
245 then iteration will continue.
246 However, if
247 .Fa func
248 returns non-zero, then iteration will halt and that value will be used
249 as the return value of the
250 .Fn Psymbol_iter ,
251 .Fn Psymbol_iter_by_addr ,
252 .Fn Psymbol_iter_by_lmid ,
253 .Fn Psymbol_iter_by_name ,
254 and
255 .Fn Pxsymbol_iter
256 functions.
257 Because these functions return
258 .Sy -1
259 on internal failure, it is recommended that the callback function not return
260 .Sy -1
261 to indicate an error so that the caller may distinguish between the
262 failure of the callback function and the failure of these functions.
263 .Sh RETURN VALUES
264 Upon successful completion, the
265 .Fn Psymbol_iter ,
266 .Fn Psymbol_iter_by_addr ,
267 .Fn Psymbol_iter_by_lmid ,
268 .Fn Psymbol_iter_by_name ,
269 and
270 .Fn Pxsymbol_iter
271 functions return
272 .Sy 0 .
273 If there was an internal error then
274 .Sy -1
275 is returned.
276 Otherwise, if the callback function
277 .Fa func
278 returns non-zero, then its return value will be returned instead.
279 .Sh INTERFACE STABILITY
280 .Sy Uncommitted
281 .Sh MT-LEVEL
282 See
283 .Sy LOCKING
284 in
285 .Xr libproc 3LIB .
286 .Sh SEE ALSO
287 .Xr elf 3ELF ,
288 .Xr gelf 3ELF ,
289 .Xr libproc 3LIB ,
290 .Xr proc 4