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Re: [PATCH 1/5] tools/libxl: Mark pointer args of many functions constant

From: Luca Fancellu <luca.fancellu@xxxxxxx>

Date: Wed, 29 Dec 2021 17:15:25 +0000

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Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>

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> On 18 Dec 2020, at 21:37, Elliott Mitchell <ehem+xen@xxxxxxx> wrote: > > Anything *_is_empty(), *_is_default(), or *_gen_json() is going to be > examining the pointed to thing, not modifying it. This potentially > results in higher-performance output. This also allows spreading > constants further, allowing more checking and security. Looks ok to me Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx> > > Signed-off-by: Elliott Mitchell <ehem+xen@xxxxxxx> > --- > tools/include/libxl_json.h | 22 ++++++++++++---------- > tools/libs/light/gentypes.py | 8 ++++---- > tools/libs/light/libxl_cpuid.c | 2 +- > tools/libs/light/libxl_internal.c | 4 ++-- > tools/libs/light/libxl_internal.h | 18 +++++++++--------- > tools/libs/light/libxl_json.c | 18 ++++++++++-------- > tools/libs/light/libxl_nocpuid.c | 4 ++-- > 7 files changed, 40 insertions(+), 36 deletions(-) > > diff --git a/tools/include/libxl_json.h b/tools/include/libxl_json.h > index 260783bfde..63f0e58fe1 100644 > --- a/tools/include/libxl_json.h > +++ b/tools/include/libxl_json.h > @@ -23,17 +23,19 @@ > #endif > > yajl_gen_status libxl__uint64_gen_json(yajl_gen hand, uint64_t val); > -yajl_gen_status libxl_defbool_gen_json(yajl_gen hand, libxl_defbool *p); > -yajl_gen_status libxl_uuid_gen_json(yajl_gen hand, libxl_uuid *p); > -yajl_gen_status libxl_mac_gen_json(yajl_gen hand, libxl_mac *p); > -yajl_gen_status libxl_bitmap_gen_json(yajl_gen hand, libxl_bitmap *p); > +yajl_gen_status libxl_defbool_gen_json(yajl_gen hand, const libxl_defbool > *p); > +yajl_gen_status libxl_uuid_gen_json(yajl_gen hand, const libxl_uuid *p); > +yajl_gen_status libxl_mac_gen_json(yajl_gen hand, const libxl_mac *p); > +yajl_gen_status libxl_bitmap_gen_json(yajl_gen hand, const libxl_bitmap *p); > yajl_gen_status libxl_cpuid_policy_list_gen_json(yajl_gen hand, > - libxl_cpuid_policy_list *p); > -yajl_gen_status libxl_string_list_gen_json(yajl_gen hand, libxl_string_list > *p); > + const > libxl_cpuid_policy_list *p); > +yajl_gen_status libxl_string_list_gen_json(yajl_gen hand, > + const libxl_string_list *p); > yajl_gen_status libxl_key_value_list_gen_json(yajl_gen hand, > - libxl_key_value_list *p); > -yajl_gen_status libxl_hwcap_gen_json(yajl_gen hand, libxl_hwcap *p); > -yajl_gen_status libxl_ms_vm_genid_gen_json(yajl_gen hand, libxl_ms_vm_genid > *p); > + const libxl_key_value_list *p); > +yajl_gen_status libxl_hwcap_gen_json(yajl_gen hand, const libxl_hwcap *p); > +yajl_gen_status libxl_ms_vm_genid_gen_json(yajl_gen hand, > + const libxl_ms_vm_genid *p); > > #include <_libxl_types_json.h> > > @@ -91,6 +93,6 @@ static inline yajl_gen libxl_yajl_gen_alloc(const > yajl_alloc_funcs *allocFuncs) > #endif /* !HAVE_YAJL_V2 */ > > yajl_gen_status libxl_domain_config_gen_json(yajl_gen hand, > - libxl_domain_config *p); > + const libxl_domain_config *p); > > #endif /* LIBXL_JSON_H */ > diff --git a/tools/libs/light/gentypes.py b/tools/libs/light/gentypes.py > index 9a45e45acc..7e02a5366f 100644 > --- a/tools/libs/light/gentypes.py > +++ b/tools/libs/light/gentypes.py > @@ -632,7 +632,7 @@ if __name__ == '__main__': > ty.make_arg("p"), > > ku.keyvar.type.make_arg(ku.keyvar.name))) > if ty.json_gen_fn is not None: > - f.write("%schar *%s_to_json(libxl_ctx *ctx, %s);\n" % > (ty.hidden(), ty.typename, ty.make_arg("p"))) > + f.write("%schar *%s_to_json(libxl_ctx *ctx, const %s);\n" % > (ty.hidden(), ty.typename, ty.make_arg("p"))) > if ty.json_parse_fn is not None: > f.write("%sint %s_from_json(libxl_ctx *ctx, %s, const char > *s);\n" % (ty.hidden(), ty.typename, ty.make_arg("p", > passby=idl.PASS_BY_REFERENCE))) > if isinstance(ty, idl.Enumeration): > @@ -662,7 +662,7 @@ if __name__ == '__main__': > """ % (header_json_define, header_json_define, " ".join(sys.argv))) > > for ty in [ty for ty in types if ty.json_gen_fn is not None]: > - f.write("%syajl_gen_status %s_gen_json(yajl_gen hand, %s);\n" % > (ty.hidden(), ty.typename, ty.make_arg("p", passby=idl.PASS_BY_REFERENCE))) > + f.write("%syajl_gen_status %s_gen_json(yajl_gen hand, const %s);\n" > % (ty.hidden(), ty.typename, ty.make_arg("p", passby=idl.PASS_BY_REFERENCE))) > > f.write("\n") > f.write("""#endif /* %s */\n""" % header_json_define) > @@ -766,13 +766,13 @@ if __name__ == '__main__': > f.write("\n") > > for ty in [t for t in types if t.json_gen_fn is not None]: > - f.write("yajl_gen_status %s_gen_json(yajl_gen hand, %s)\n" % > (ty.typename, ty.make_arg("p", passby=idl.PASS_BY_REFERENCE))) > + f.write("yajl_gen_status %s_gen_json(yajl_gen hand, const %s)\n" % > (ty.typename, ty.make_arg("p", passby=idl.PASS_BY_REFERENCE))) > f.write("{\n") > f.write(libxl_C_type_gen_json(ty, "p")) > f.write("}\n") > f.write("\n") > > - f.write("char *%s_to_json(libxl_ctx *ctx, %s)\n" % (ty.typename, > ty.make_arg("p"))) > + f.write("char *%s_to_json(libxl_ctx *ctx, const %s)\n" % > (ty.typename, ty.make_arg("p"))) > f.write("{\n") > f.write(libxl_C_type_to_json(ty, "p")) > f.write("}\n") > diff --git a/tools/libs/light/libxl_cpuid.c b/tools/libs/light/libxl_cpuid.c > index e1acf6648d..b076d7f4a3 100644 > --- a/tools/libs/light/libxl_cpuid.c > +++ b/tools/libs/light/libxl_cpuid.c > @@ -14,7 +14,7 @@ > > #include "libxl_internal.h" > > -int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl) > +int libxl__cpuid_policy_is_empty(const libxl_cpuid_policy_list *pl) > { > return !libxl_cpuid_policy_list_length(pl); > } > diff --git a/tools/libs/light/libxl_internal.c > b/tools/libs/light/libxl_internal.c > index 86556b6113..da2dbd67ad 100644 > --- a/tools/libs/light/libxl_internal.c > +++ b/tools/libs/light/libxl_internal.c > @@ -333,7 +333,7 @@ _hidden int libxl__parse_mac(const char *s, libxl_mac mac) > return 0; > } > > -_hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b) > +_hidden int libxl__compare_macs(const libxl_mac *a, const libxl_mac *b) > { > int i; > > @@ -345,7 +345,7 @@ _hidden int libxl__compare_macs(libxl_mac *a, libxl_mac > *b) > return 0; > } > > -_hidden int libxl__mac_is_default(libxl_mac *mac) > +_hidden int libxl__mac_is_default(const libxl_mac *mac) > { > return (!(*mac)[0] && !(*mac)[1] && !(*mac)[2] && > !(*mac)[3] && !(*mac)[4] && !(*mac)[5]); > diff --git a/tools/libs/light/libxl_internal.h > b/tools/libs/light/libxl_internal.h > index 37d5c27756..117a98acab 100644 > --- a/tools/libs/light/libxl_internal.h > +++ b/tools/libs/light/libxl_internal.h > @@ -2080,9 +2080,9 @@ struct libxl__xen_console_reader { > /* parse the string @s as a sequence of 6 colon separated bytes in to @mac */ > _hidden int libxl__parse_mac(const char *s, libxl_mac mac); > /* compare mac address @a and @b. 0 if the same, -ve if a<b and +ve if a>b */ > -_hidden int libxl__compare_macs(libxl_mac *a, libxl_mac *b); > +_hidden int libxl__compare_macs(const libxl_mac *a, const libxl_mac *b); > /* return true if mac address is all zero (the default value) */ > -_hidden int libxl__mac_is_default(libxl_mac *mac); > +_hidden int libxl__mac_is_default(const libxl_mac *mac); > /* init a recursive mutex */ > _hidden int libxl__init_recursive_mutex(libxl_ctx *ctx, pthread_mutex_t > *lock); > > @@ -4580,7 +4580,7 @@ _hidden int libxl__ms_vm_genid_set(libxl__gc *gc, > uint32_t domid, > #define LIBXL__DEFBOOL_STR_DEFAULT "<default>" > #define LIBXL__DEFBOOL_STR_FALSE "False" > #define LIBXL__DEFBOOL_STR_TRUE "True" > -static inline int libxl__defbool_is_default(libxl_defbool *db) > +static inline int libxl__defbool_is_default(const libxl_defbool *db) > { > return !db->val; > } > @@ -4675,22 +4675,22 @@ int libxl__random_bytes(libxl__gc *gc, uint8_t *buf, > size_t len); > #include "_libxl_types_internal_private.h" > > /* This always return false, there's no "default value" for hw cap */ > -static inline int libxl__hwcap_is_default(libxl_hwcap *hwcap) > +static inline int libxl__hwcap_is_default(const libxl_hwcap *hwcap) > { > return 0; > } > > -static inline int libxl__string_list_is_empty(libxl_string_list *psl) > +static inline int libxl__string_list_is_empty(const libxl_string_list *psl) > { > return !libxl_string_list_length(psl); > } > > -static inline int libxl__key_value_list_is_empty(libxl_key_value_list *pkvl) > +static inline int libxl__key_value_list_is_empty(const libxl_key_value_list > *pkvl) > { > return !libxl_key_value_list_length(pkvl); > } > > -int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl); > +int libxl__cpuid_policy_is_empty(const libxl_cpuid_policy_list *pl); > > /* Portability note: a proper flock(2) implementation is required */ > typedef struct { > @@ -4821,12 +4821,12 @@ void* libxl__device_list(libxl__gc *gc, const > libxl__device_type *dt, > void libxl__device_list_free(const libxl__device_type *dt, > void *list, int num); > > -static inline bool libxl__timer_mode_is_default(libxl_timer_mode *tm) > +static inline bool libxl__timer_mode_is_default(const libxl_timer_mode *tm) > { > return *tm == LIBXL_TIMER_MODE_DEFAULT; > } > > -static inline bool libxl__string_is_default(char **s) > +static inline bool libxl__string_is_default(char *const *s) > { > return *s == NULL; > } > diff --git a/tools/libs/light/libxl_json.c b/tools/libs/light/libxl_json.c > index 9b8ef2cab9..88e81f9905 100644 > --- a/tools/libs/light/libxl_json.c > +++ b/tools/libs/light/libxl_json.c > @@ -95,7 +95,7 @@ yajl_gen_status libxl__yajl_gen_enum(yajl_gen hand, const > char *str) > * YAJL generators for builtin libxl types. > */ > yajl_gen_status libxl_defbool_gen_json(yajl_gen hand, > - libxl_defbool *db) > + const libxl_defbool *db) > { > return libxl__yajl_gen_asciiz(hand, libxl_defbool_to_string(*db)); > } > @@ -137,7 +137,7 @@ int libxl__bool_parse_json(libxl__gc *gc, const > libxl__json_object *o, > } > > yajl_gen_status libxl_uuid_gen_json(yajl_gen hand, > - libxl_uuid *uuid) > + const libxl_uuid *uuid) > { > char buf[LIBXL_UUID_FMTLEN+1]; > snprintf(buf, sizeof(buf), LIBXL_UUID_FMT, LIBXL_UUID_BYTES((*uuid))); > @@ -154,7 +154,7 @@ int libxl__uuid_parse_json(libxl__gc *gc, const > libxl__json_object *o, > } > > yajl_gen_status libxl_bitmap_gen_json(yajl_gen hand, > - libxl_bitmap *bitmap) > + const libxl_bitmap *bitmap) > { > yajl_gen_status s; > int i; > @@ -208,7 +208,7 @@ int libxl__bitmap_parse_json(libxl__gc *gc, const > libxl__json_object *o, > } > > yajl_gen_status libxl_key_value_list_gen_json(yajl_gen hand, > - libxl_key_value_list *pkvl) > + const libxl_key_value_list > *pkvl) > { > libxl_key_value_list kvl = *pkvl; > yajl_gen_status s; > @@ -269,7 +269,8 @@ int libxl__key_value_list_parse_json(libxl__gc *gc, const > libxl__json_object *o, > return 0; > } > > -yajl_gen_status libxl_string_list_gen_json(yajl_gen hand, libxl_string_list > *pl) > +yajl_gen_status libxl_string_list_gen_json(yajl_gen hand, > + const libxl_string_list *pl) > { > libxl_string_list l = *pl; > yajl_gen_status s; > @@ -322,7 +323,7 @@ int libxl__string_list_parse_json(libxl__gc *gc, const > libxl__json_object *o, > return 0; > } > > -yajl_gen_status libxl_mac_gen_json(yajl_gen hand, libxl_mac *mac) > +yajl_gen_status libxl_mac_gen_json(yajl_gen hand, const libxl_mac *mac) > { > char buf[LIBXL_MAC_FMTLEN+1]; > snprintf(buf, sizeof(buf), LIBXL_MAC_FMT, LIBXL_MAC_BYTES((*mac))); > @@ -339,7 +340,7 @@ int libxl__mac_parse_json(libxl__gc *gc, const > libxl__json_object *o, > } > > yajl_gen_status libxl_hwcap_gen_json(yajl_gen hand, > - libxl_hwcap *p) > + const libxl_hwcap *p) > { > yajl_gen_status s; > int i; > @@ -377,7 +378,8 @@ int libxl__hwcap_parse_json(libxl__gc *gc, const > libxl__json_object *o, > return 0; > } > > -yajl_gen_status libxl_ms_vm_genid_gen_json(yajl_gen hand, libxl_ms_vm_genid > *p) > +yajl_gen_status libxl_ms_vm_genid_gen_json(yajl_gen hand, > + const libxl_ms_vm_genid *p) > { > yajl_gen_status s; > int i; > diff --git a/tools/libs/light/libxl_nocpuid.c > b/tools/libs/light/libxl_nocpuid.c > index 0630959e76..f40a004e95 100644 > --- a/tools/libs/light/libxl_nocpuid.c > +++ b/tools/libs/light/libxl_nocpuid.c > @@ -14,7 +14,7 @@ > > #include "libxl_internal.h" > > -int libxl__cpuid_policy_is_empty(libxl_cpuid_policy_list *pl) > +int libxl__cpuid_policy_is_empty(const libxl_cpuid_policy_list *pl) > { > return 1; > } > @@ -41,7 +41,7 @@ int libxl__cpuid_legacy(libxl_ctx *ctx, uint32_t domid, > bool restore, > } > > yajl_gen_status libxl_cpuid_policy_list_gen_json(yajl_gen hand, > - libxl_cpuid_policy_list *pcpuid) > + const libxl_cpuid_policy_list *pcpuid) > { > return 0; > } > -- > 2.30.2 > >

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