1 /* 2 * This file is part of ltrace. 3 * Copyright (C) 2011,2012 Petr Machata, Red Hat Inc. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation; either version 2 of the 8 * License, or (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 18 * 02110-1301 USA 19 */ 20 21 #ifndef VALUE_H 22 #define VALUE_H 23 24 #include "forward.h" 25 #include "sysdep.h" 26 27 /* Values are objects that capture data fetched from an inferior. 28 * Typically a value is attached to a single inferior where it was 29 * extracted from, but it is possible to create a detached value. 30 * Each value is typed. Values support a number of routines, such as 31 * dereferencing if the value is of pointer type, array or structure 32 * access, etc. 33 * 34 * A value can be uninitialized, abstract or reified. Abstract values 35 * are just references into inferior, no transfer has taken place yet. 36 * Reified values have been copied out of the corresponding inferior, 37 * or otherwise set to some value. */ 38 39 enum value_location_t { 40 VAL_LOC_NODATA = 0, /* Uninitialized. */ 41 VAL_LOC_INFERIOR, /* Value is in the inferior process. */ 42 VAL_LOC_COPY, /* Value was copied out of the inferior. */ 43 VAL_LOC_SHARED, /* Like VAL_LOC_COPY, but don't free. */ 44 VAL_LOC_WORD, /* Like VAL_LOC_COPY, but small enough. */ 45 }; 46 47 struct value { 48 struct arg_type_info *type; 49 struct process *inferior; 50 struct value *parent; 51 size_t size; 52 union { 53 void *address; /* VAL_LOC_COPY, VAL_LOC_SHARED */ 54 arch_addr_t inf_address; /* VAL_LOC_INFERIOR */ 55 long value; /* VAL_LOC_WORD */ 56 unsigned char buf[0]; 57 } u; 58 enum value_location_t where; 59 int own_type; 60 }; 61 62 /* Initialize VALUE. INFERIOR must not be NULL. PARENT is parental 63 * value, in case of compound types. It may be NULL. TYPE is a type 64 * of the value. It may be NULL if the type is not yet known. If 65 * OWN_TYPE, the passed-in type is owned and released by value. */ 66 void value_init(struct value *value, struct process *inferior, 67 struct value *parent, struct arg_type_info *type, 68 int own_type); 69 70 /* Initialize VALUE. This is like value_init, except that inferior is 71 * NULL. VALP is initialized as a detached value, without assigned 72 * process. You have to be careful not to use VAL_LOC_INFERIOR 73 * values if the value is detached. */ 74 void value_init_detached(struct value *value, struct value *parent, 75 struct arg_type_info *type, int own_type); 76 77 /* Set TYPE. This releases old type if it was owned. TYPE is owned 78 * and released if OWN_TYPE. */ 79 void value_set_type(struct value *value, 80 struct arg_type_info *type, int own_type); 81 82 /* Transfers the ownership of VALUE's type, if any, to the caller. 83 * This doesn't reset the VALUE's type, but gives up ownership if 84 * there was one. Previous ownership is passed in OWN_TYPE. */ 85 void value_take_type(struct value *value, 86 struct arg_type_info **type, int *own_type); 87 88 /* Release the data held by VALP, if any, but not the type. */ 89 void value_release(struct value *valp); 90 91 /* Value resides in inferior, on given ADDRESS. */ 92 void value_in_inferior(struct value *valp, arch_addr_t address); 93 94 /* Destroy the value. This is like value_release, but it additionally 95 * frees the value type, if it's own_type. It doesn't free the VAL 96 * pointer itself. */ 97 void value_destroy(struct value *val); 98 99 /* Set the data held by VALP to VALUE. This also sets the value's 100 * where to VAL_LOC_WORD. */ 101 void value_set_word(struct value *valp, long value); 102 103 /* Set the data held by VALP to a buffer of size SIZE. This buffer 104 * may be allocated by malloc. Returns NULL on failure. */ 105 unsigned char *value_reserve(struct value *valp, size_t size); 106 107 /* Access ELEMENT-th field of the compound value VALP, and store the 108 * result into the value RET_VAL. Returns 0 on success, or negative 109 * value on failure. */ 110 int value_init_element(struct value *ret_val, struct value *valp, size_t element); 111 112 /* De-reference pointer value, and store the result into the value 113 * RET_VAL. Returns 0 on success, or negative value on failure. */ 114 int value_init_deref(struct value *ret_val, struct value *valp); 115 116 /* If value is in inferior, copy it over to ltrace. Return 0 for 117 * success or negative value for failure. */ 118 int value_reify(struct value *val, struct value_dict *arguments); 119 120 /* Return a pointer to the data of the value. This copies the data 121 * from the inferior to the tracer. Returns NULL on failure. */ 122 unsigned char *value_get_data(struct value *val, struct value_dict *arguments); 123 124 /* Return a pointer to the raw data of the value. This shall not be 125 * called on a VAL_LOC_INFERIOR value. */ 126 unsigned char *value_get_raw_data(struct value *val); 127 128 /* Copy value VAL into the area pointed-to by RETP. Return 0 on 129 * success or a negative value on failure. */ 130 int value_clone(struct value *retp, const struct value *val); 131 132 /* Give a size of given value. Return (size_t)-1 for error. This is 133 * a full size of the value. In particular for arrays, it returns 134 * actual length of the array, as computed by the length 135 * expression. */ 136 size_t value_size(struct value *val, struct value_dict *arguments); 137 138 /* Extract at most word-sized datum from the value. Return 0 on 139 * success or negative value on failure. */ 140 int value_extract_word(struct value *val, long *retp, 141 struct value_dict *arguments); 142 143 /* Copy contents of VAL to DATA. The buffer must be large enough to 144 * hold all the data inside. */ 145 int value_extract_buf(struct value *val, unsigned char *data, 146 struct value_dict *arguments); 147 148 /* Find the most enclosing parental value that is a struct. Return 149 * NULL when there is no such parental value. */ 150 struct value *value_get_parental_struct(struct value *val); 151 152 /* Determine whether this is all-zero value. Returns >0 if it is, ==0 153 * if it isn't, <0 on error. */ 154 int value_is_zero(struct value *val, struct value_dict *arguments); 155 156 /* Compare two values for byte-by-byte equality. Returns >0 if they 157 * are equal, ==0 if they are not, and <0 on error. */ 158 int value_equal(struct value *val1, struct value *val2, 159 struct value_dict *arguments); 160 161 /* Convert a structure type to pointer to that structure type. */ 162 int value_pass_by_reference(struct value *value); 163 164 #endif /* VALUE_H */ 165