Merge 413f6e0f56 into af3baf174a

Adds VA_MACRO_HELPER() which allows calling another macro with temporary
variables, unique tokens, and/or existing variables protected from side
effects.

Also adds various other helper macros for dealing with variadic args, such as
VA_GROUP(), VA_IF(), VA_FIRST(), etc.

src/basic/fs-util.c

@@ -1131,6 +1131,8 @@ int xopenat_full(int dir_fd, const char *path, int open_flags, XOpenFlags xopen_
          *   • If O_CREAT is used with XO_LABEL, any created file will be immediately relabelled.
          *
          *   • If the path is specified NULL or empty, behaves like fd_reopen().
+         *
+         *   • If XO_NOCOW is specified will turn on the NOCOW btrfs flag on the file, if available.
          */
 
         if (isempty(path)) {

src/fundamental/macro-fundamental.h

@@ -90,8 +90,8 @@
 #  define _fallthrough_
 #endif
 
-#define XSTRINGIFY(x) #x
+#define XSTRINGIFY(...) #__VA_ARGS__
-#define STRINGIFY(x) XSTRINGIFY(x)
+#define STRINGIFY(...) XSTRINGIFY(__VA_ARGS__)
 
 #ifndef __COVERITY__
 #  define VOID_0 ((void)0)

src/fundamental/variadic-fundamental.h

@@ -0,0 +1,555 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/* This contains macros that all help simplify the use of macros with variadic args. Also provided is a macro
+ * 'helper' that helps provide some commonly used things, such as a unique variable name or temporary
+ * variable.
+ *
+ * Since the C preprocessor does not allow recursive macros, none of these macros may be used to call
+ * themselves, even indirectly (except by using a "trick"; e.g. see __VA_WRAP_RECURSE() below). If you get a
+ * compiler error complaining about "implicit declaration of function" for any of the macros here, it is most
+ * likely due to an attempt to use the macro recursively.
+ *
+ * Some macros operate based on if there are 'any variadic args' or 'no variadic args'; this distinction is
+ * based on the use of __VA_OPT__(). The description 'any variadic args' means __VA_OPT__() evaluates to its
+ * content, and 'no variadic args' means __VA_OPT__() evaluates to nothing. Note that whitespace is not a
+ * preprocessor token, so a single whitespace-only arg is the same as no args. For example these calls all
+ * evaluate to 2:
+ *   VA_IF_ELSE(1,2)
+ *   VA_IF_ELSE(1,2,)
+ *   VA_IF_ELSE(1,2, )
+ *   #define NONE
+ *   VA_IF_ELSE(1,2,NONE)
+ *   VA_IF_ELSE(1,2, NONE)
+ * However, this call evaluates to 1:
+ *   VA_IF_ELSE(1,2,,)
+ */
+
+/* Wraps variadic args in a single group. This can be passed to macros that will then expand the group into
+ * all its variadic args. */
+#define VA_GROUP(...) __VA_ARGS__
+
+/* Evaluates to 'x' if any variadic args, otherwise 'y'. */
+#define VA_IF_ELSE(x, y, ...) _VA_IF_ELSE_MACRO(__VA_ARGS__)(_VA_IF_ELSE_GROUP(x), _VA_IF_ELSE_GROUP(y))
+#define _VA_IF_ELSE_GROUP(...) __VA_ARGS__
+#define _VA_IF_ELSE_MACRO(...) __VA_IF_ELSE_MACRO(__VA_OPT__(1))
+#define __VA_IF_ELSE_MACRO(o) _VA_IF_ELSE ## o
+#define _VA_IF_ELSE1(x, y) x
+#define _VA_IF_ELSE(x, y) y
+
+/* Evaluates to nothing if no variadic args, otherwise 'x'. */
+#define VA_IF(x, ...) VA_IF_ELSE(_VA_IF_GROUP(x), /*false*/, __VA_ARGS__)
+#define _VA_IF_GROUP(...) __VA_ARGS__
+
+/* Same as VA_IF() but negates the condition. */
+#define VA_IF_NOT(x, ...) VA_IF_ELSE(/*true*/, _VA_IF_NOT_GROUP(x), __VA_ARGS__)
+#define _VA_IF_NOT_GROUP(...) __VA_ARGS__
+
+/* Evaluates to token 1 if no variadic args, otherwise nothing. */
+#define VA_NOT(...) VA_IF_NOT(1, __VA_ARGS__)
+
+/* Evaluates to the first variadic arg, otherwise nothing. */
+#define VA_FIRST(...) VA_IF(_VA_FIRST(__VA_ARGS__), __VA_ARGS__)
+#define _VA_FIRST(x, ...) x
+
+/* Evaluates to the rest of the variadic args, after the first, otherwise nothing. */
+#define VA_REST(...) VA_IF(_VA_REST(__VA_ARGS__), __VA_ARGS__)
+#define _VA_REST(x, ...) __VA_ARGS__
+
+/* Evaluates to token , if any variadic args, otherwise nothing. */
+#define VA_COMMA(...) __VA_OPT__(,)
+
+/* Evaluates to token 1 if both args are non-empty (ignoring whitespace), otherwise evaluates to nothing. */
+#define VA_AND(x, y) VA_NOT(VA_NOT(x) VA_NOT(y))
+
+/* Evaluates to token 1 if either arg is non-empty (ignoring whitespace), otherwise evaluates to nothing. */
+#define VA_OR(x, y) VA_IF(1, x y)
+
+/* Evaluates to nothing. */
+#define VA_NOOP(...)
+
+/* Similar to VA_GROUP(), but encloses the variadic args in (), so they are not expanded when passed to other
+ * macros. Unlike VA_GROUP(), this requires the final macro that actually uses the group contents to ungroup it
+ * using VA_UNPGROUP(), or to handle the () directly. */
+#define VA_PGROUP(...) (__VA_ARGS__)
+
+/* Converts a group of args protected with () into a normal VA_GROUP(). 'x' must be a pgroup, i.e. (...). */
+#define VA_UNPGROUP(x) VA_GROUP x
+
+/* Similar to VA_FIRST(), but x is a pgroup. Evaluates to the first arg if present, otherwise nothing. */
+#define VA_PGROUP_FIRST(x) VA_FIRST(VA_UNPGROUP(x))
+
+/* Similar to VA_REST(), but x is a pgroup. Evaluates to a pgroup of the args after the first. If there are
+ * no more args after the first, evaluates to an empty pgroup. */
+#define VA_PGROUP_REST(x) VA_PGROUP(VA_REST(VA_UNPGROUP(x)))
+
+/* Evaluates to token 1 if pgroup is empty, otherwise nothing. */
+#define VA_PGROUP_EMPTY(x) VA_IF_NOT(1, VA_UNPGROUP(x))
+
+/* Similar to VA_PGROUP_EMPTY() but negates the condition. */
+#define VA_PGROUP_NOT_EMPTY(x) VA_NOT(VA_PGROUP_EMPTY(x))
+
+/* Evaluates to 'macro' called with the expanded variadic args. */
+#define VA_MACRO(macro, ...) macro(__VA_ARGS__)
+
+/* Evaluates to x(__VA_ARGS__) if t is non-empty, otherwise y(__VA_ARGS__). */
+#define VA_MACRO_IF_ELSE(x, y, t, ...) VA_IF_ELSE(x, y, t)(__VA_ARGS__)
+
+/* Evaluates to m(__VA_ARGS__) if t is non-empty, otherwise nothing. */
+#define VA_MACRO_IF(m, t, ...) VA_MACRO_IF_ELSE(m, VA_NOOP, t, __VA_ARGS__)
+
+/* Evaluates to m(__VA_ARGS__) if t is empty, otherwise nothing. */
+#define VA_MACRO_IF_NOT(m, t, ...) VA_MACRO_IF_ELSE(VA_NOOP, m, t, __VA_ARGS__)
+
+/* Same as VA_MACRO() but takes a pgroup, which is unpgrouped before passing to the macro. */
+#define VA_MACRO_PGROUP(macro, pgroup) VA_MACRO(macro, VA_UNPGROUP(pgroup))
+
+/* Expands to 'macro' for each variadic arg, which will be called with:
+ *   1) the provided 'context'
+ *   2) a hex iteration number (starting at 0x0001)
+ *   3) the variadic arg
+ *   4...) the rest of the variadic args
+ *
+ * Each expansion of 'macro', except for the last, will be followed by 'separator' called with the same
+ * parameters as 'macro'.
+ *
+ * If there are no variadic args, this evaluates to 'zero' called with the single arg 'context'.
+ *
+ * If there are too many variadic args, this evaluates to 'toomany' called with the single arg 'context'.
+ *
+ * The 'macro', 'separator', 'zero', and 'toomany' parameters must be callable macros. The VA_WRAP_*() macros
+ * below may be used. The 'context' parameter may be anything and is not directly called (except by the
+ * VA_WRAP_*_CONTEXT() below). */
+#define VA_WRAP(macro, separator, context, zero, toomany, ...)          \
+        __VA_WRAP_RECURSE(macro, separator, context, zero, toomany, __VA_ARGS__)
+
+/* These can be used for the VA_WRAP() 'macro' parameter. */
+#define VA_WRAP_MACRO_CONTEXT(c, i, v, ...) c
+#define VA_WRAP_MACRO_INDEX(c, i, v, ...) i
+#define VA_WRAP_MACRO_LAST(c, i, v, ...) VA_IF_NOT(v, __VA_ARGS__)
+#define VA_WRAP_MACRO_LAST_INDEX(c, i, v, ...) VA_IF_NOT(i, __VA_ARGS__)
+#define VA_WRAP_MACRO_NONE(c, i, v, ...)
+#define VA_WRAP_MACRO_VALUE(c, i, v, ...) v
+
+/* These can be used for the VA_WRAP() 'separator' parameter. */
+#define VA_WRAP_SEPARATOR_AND(c, i, v, ...) &&
+#define VA_WRAP_SEPARATOR_COMMA(c, i, v, ...) ,
+#define VA_WRAP_SEPARATOR_COMMA_IF_PREV(c, i, v, ...) VA_COMMA(v)
+#define VA_WRAP_SEPARATOR_CONTEXT(c, i, v, ...) c
+#define VA_WRAP_SEPARATOR_INDEX(c, i, v, ...) i
+#define VA_WRAP_SEPARATOR_NONE(c, i, v, ...)
+#define VA_WRAP_SEPARATOR_SEMICOLON(c, i, v, ...) ;
+
+/* This can be used for the VA_WRAP() 'context' parameter. It is strictly to help with code readability, and
+ * is not required. */
+#define VA_WRAP_CONTEXT_NONE
+
+/* These can be used for the VA_WRAP() 'zero' parameter. */
+#define VA_WRAP_ZERO_0(c) 0
+#define VA_WRAP_ZERO_0x0000(c) 0x0000
+#define VA_WRAP_ZERO_CONTEXT(c) c
+#define VA_WRAP_ZERO_ERROR(c) _Pragma("GCC error \"Zero variadic args.\"")
+#define VA_WRAP_ZERO_FALSE(c) false
+#define VA_WRAP_ZERO_NONE(c)
+#define VA_WRAP_ZERO_TRUE(c) true
+#define VA_WRAP_ZERO_VOID_0(c) VOID_0
+
+/* These can be used for the VA_WRAP() 'toomany' parameter. */
+#define VA_WRAP_TOOMANY_CONTEXT(c) c
+#define VA_WRAP_TOOMANY_ERROR(c) _Pragma("GCC error \"Too many variadic args.\"")
+#define VA_WRAP_TOOMANY_FALSE(c) false
+#define VA_WRAP_TOOMANY_NONE(c)
+#define VA_WRAP_TOOMANY_TRUE(c) true
+
+/* Simple version of VA_WRAP(); each variadic arg is wrapped by the provided macro, separated by commas. No
+ * context is used. Zero args evaluates to nothing. Toomany args results in error. */
+#define VA_MACRO_FOREACH(macro, ...)            \
+        VA_WRAP(macro,                          \
+                VA_WRAP_SEPARATOR_COMMA,        \
+                VA_WRAP_CONTEXT_NONE,           \
+                VA_WRAP_ZERO_NONE,              \
+                VA_WRAP_TOOMANY_ERROR,          \
+                __VA_ARGS__)
+
+/* Expands to list of variadic args, with any "empty" (whitespace only) args removed. This processes the list
+ * twice, to remove a trailing comma if needed. */
+#define VA_FILTER(...)                                          \
+        VA_MACRO(VA_WRAP,                                       \
+                 VA_WRAP_MACRO_VALUE,                           \
+                 VA_WRAP_SEPARATOR_COMMA_IF_PREV,               \
+                 VA_WRAP_CONTEXT_NONE,                          \
+                 VA_WRAP_ZERO_NONE,                             \
+                 VA_WRAP_TOOMANY_ERROR,                         \
+                 VA_WRAP(VA_WRAP_MACRO_VALUE,                   \
+                         VA_WRAP_SEPARATOR_COMMA_IF_PREV,       \
+                         VA_WRAP_CONTEXT_NONE,                  \
+                         VA_WRAP_ZERO_NONE,                     \
+                         VA_WRAP_TOOMANY_ERROR,                 \
+                         __VA_ARGS__))
+
+/* Evaluates to the number of variadic args. */
+#define VA_NARGS(...)                                                   \
+        VA_WRAP(VA_WRAP_MACRO_LAST_INDEX,                               \
+                VA_WRAP_SEPARATOR_NONE,                                 \
+                VA_WRAP_CONTEXT_NONE,                                   \
+                VA_WRAP_ZERO_0x0000,                                    \
+                VA_WRAP_TOOMANY_ERROR,                                  \
+                __VA_ARGS__)
+
+/* Evaluates to the last variadic arg. If there are no variadic args, evaluates to nothing. */
+#define VA_LAST(...)                                                    \
+        VA_WRAP(VA_WRAP_MACRO_LAST,                                     \
+                VA_WRAP_SEPARATOR_NONE,                                 \
+                VA_WRAP_CONTEXT_NONE,                                   \
+                VA_WRAP_ZERO_NONE,                                      \
+                VA_WRAP_TOOMANY_ERROR,                                  \
+                __VA_ARGS__)
+
+#define _VA_DECLARATIONS(macro, name, ...)      \
+        VA_WRAP(macro,                          \
+                VA_WRAP_SEPARATOR_SEMICOLON,    \
+                name,                           \
+                VA_WRAP_ZERO_NONE,              \
+                VA_WRAP_TOOMANY_ERROR,          \
+                __VA_ARGS__)
+
+#define _VA_DECLARATION_TOKEN(x, y) __VA_DECLARATION_TOKEN(x, y)
+#define __VA_DECLARATION_TOKEN(x, y) x ## _ ## y
+
+/* Evaluates to a variable declaration for each variadic arg. Each variadic arg must be a type. Each variable
+ * name is the concatenation of 'name', '_', and the variadic arg index (as a hex number). */
+#define VA_DECLARATIONS(name, ...)                              \
+        _VA_DECLARATIONS(_VA_DECLARATION, name, __VA_ARGS__)
+#define _VA_DECLARATION(c, i, v, ...)           \
+        v _VA_DECLARATION_TOKEN(c, i)
+
+/* Same as VA_DECLARATIONS(), but the variadic args must be variables (or constants). Each declaration
+ * uses __auto_type and is initialized to its corresponding variadic arg. */
+#define VA_INITIALIZED_DECLARATIONS(name, ...)                          \
+        _VA_DECLARATIONS(_VA_INITIALIZED_DECLARATION, name, __VA_ARGS__)
+#define _VA_INITIALIZED_DECLARATION(c, i, v, ...)               \
+        _VA_DECLARATION(c, i, __auto_type, __VA_ARGS__) = (v)
+
+/* Same as VA_INITIALIZED_DECLARATIONS(), but the temp variable is declared with const. */
+#define VA_CONST_INITIALIZED_DECLARATIONS(name, ...)                    \
+        _VA_DECLARATIONS(_VA_CONST_INITIALIZED_DECLARATION, name, __VA_ARGS__)
+#define _VA_CONST_INITIALIZED_DECLARATION(c, i, v, ...)                 \
+        const _VA_INITIALIZED_DECLARATION(c, i, v, __VA_ARGS__)
+
+/* Evaluates to a comma-separated list of tokens by concatenating 'name' and a literal '_' with each variadic
+ * arg index. This will produce the same tokens as the variable names generated by VA_DECLARATIONS(). Note
+ * this does not actually evaluate any of the variadic args. */
+#define VA_TOKENS(name, ...)                                            \
+        VA_WRAP(_VA_TOKEN,                                              \
+                VA_WRAP_SEPARATOR_COMMA,                                \
+                name,                                                   \
+                VA_WRAP_ZERO_NONE,                                      \
+                VA_WRAP_TOOMANY_ERROR,                                  \
+                __VA_ARGS__)
+#define _VA_TOKEN(c, i, v, ...) _VA_DECLARATION_TOKEN(c, i)
+
+/* Evaluates to a comma-separated list of unique tokens using UNIQ_T() for each variadic arg. This is similar
+ * to VA_TOKENS() but uses UNIQ_T() to generate the tokens. */
+#define VA_UNIQ(...)                                                    \
+        VA_WRAP(_VA_UNIQ,                                               \
+                VA_WRAP_SEPARATOR_COMMA,                                \
+                UNIQ,                                                   \
+                VA_WRAP_ZERO_NONE,                                      \
+                VA_WRAP_TOOMANY_ERROR,                                  \
+                __VA_ARGS__)
+#define _VA_UNIQ(c, i, v, ...) UNIQ_T(v, c)
+
+/* This is similar to VA_FILTER(), but we can't use VA_FILTER() because macros can't be used recursively, and
+ * this is called from inside a VA_WRAP() (which VA_FILTER() relies on). */
+#define __VMH_GROUPS(g1, g2, g3, g4, g5)        \
+        g1 VA_IF(VA_COMMA(g1), g2 g3 g4 g5)     \
+        g2 VA_IF(VA_COMMA(g2), g3 g4 g5)        \
+        g3 VA_IF(VA_COMMA(g3), g4 g5)           \
+        g4 VA_IF(VA_COMMA(g4), g5)              \
+        g5
+
+#define __VMH_TOKEN(x, u) __va_macro_helper ## x ## u
+#define __VMH_STATEMENT_EXPRESSION(macro, u, uniq, var, varinit, varconst, direct) \
+        ({                                                              \
+                VA_DECLARATIONS(                  __VMH_TOKEN(_var_,      u), var); \
+                VA_INITIALIZED_DECLARATIONS(      __VMH_TOKEN(_varinit_,  u), varinit); \
+                VA_CONST_INITIALIZED_DECLARATIONS(__VMH_TOKEN(_varconst_, u), varconst); \
+                VA_MACRO(macro,                                         \
+                         __VMH_GROUPS(VA_UNIQ(uniq),                    \
+                                      VA_TOKENS(__VMH_TOKEN(_var_,      u), var), \
+                                      VA_TOKENS(__VMH_TOKEN(_varinit_,  u), varinit), \
+                                      VA_TOKENS(__VMH_TOKEN(_varconst_, u), varconst), \
+                                      VA_GROUP(direct)));               \
+        })
+
+#define __VMH_EXPRESSION(macro, u, uniq, var, varinit, varconst, direct) \
+        VA_MACRO(macro,                                                 \
+                 __VMH_GROUPS(VA_UNIQ(uniq), VA_GROUP(direct),,,))
+
+/* Calls 'macro' with a set of args based on the provided arg groups, in the order shown. Multiple args may
+ * be provided to each group by using VA_GROUP().
+ *
+ * Each arg in the 'uniq' group provides a unique token, named based on the arg token, to the macro in
+ * place of the arg. This is equivalent to UNIQ_T() for each arg.
+ *
+ * Each arg in the 'var' group provides a temporary variable of the specified type to the macro in place of
+ * the arg. All args in this group must be types.
+ *
+ * The 'varinit' group is similar to the 'var' group, but each arg must be a variable or constant, and each
+ * temporary variable is initialized to the value of the provided arg. The macro may use these args without
+ * any concern for side effects.
+ *
+ * The 'varconst' group is similar to the 'varinit' group, but the temporary variables are also marked as
+ * const. The macro should not modify args in this group.
+ *
+ * Each arg in the 'direct' group is provided directly to the macro. */
+#define VA_MACRO_HELPER(macro, uniq, var, varinit, varconst, direct)    \
+        VA_IF_ELSE(__VMH_STATEMENT_EXPRESSION,                          \
+                   __VMH_EXPRESSION,                                    \
+                   var varinit varconst)(macro,                         \
+                                         UNIQ,                          \
+                                         VA_GROUP(uniq),                \
+                                         VA_GROUP(var),                 \
+                                         VA_GROUP(varinit),             \
+                                         VA_GROUP(varconst),            \
+                                         VA_GROUP(direct))
+
+/* Same as VA_MACRO_HELPER() but only with 'uniq' group; all variadic args are put in 'direct' group. */
+#define VA_MACRO_UNIQ(macro, uniq, ...)                                 \
+        VA_MACRO_HELPER(macro,                                          \
+                        VA_GROUP(uniq),                                 \
+                        /* var=      */,                                \
+                        /* varinit=  */,                                \
+                        /* varconst= */,                                \
+                        VA_GROUP(__VA_ARGS__))
+
+/* Same as VA_MACRO_HELPER() but only with 'var' group; all variadic args are put in 'direct' group. */
+#define VA_MACRO_VAR(macro, var, ...)                                   \
+        VA_MACRO_HELPER(macro,                                          \
+                        /* uniq=     */,                                \
+                        VA_GROUP(var),                                  \
+                        /* varinit=  */,                                \
+                        /* varconst= */,                                \
+                        VA_GROUP(__VA_ARGS__))
+
+/* Same as VA_MACRO_HELPER() but only with 'varinit' group; all variadic args are put in 'direct' group. */
+#define VA_MACRO_VARINIT(macro, varinit, ...)                           \
+        VA_MACRO_HELPER(macro,                                          \
+                        /* uniq=     */,                                \
+                        /* var=      */,                                \
+                        VA_GROUP(varinit),                              \
+                        /* varconst= */,                                \
+                        VA_GROUP(__VA_ARGS__))
+
+/* Same as VA_MACRO_HELPER() but only with 'varconst' group; all variadic args are put in 'direct' group. */
+#define VA_MACRO_VARCONST(macro, varconst, ...)                         \
+        VA_MACRO_HELPER(macro,                                          \
+                        /* uniq=    */,                                 \
+                        /* var=     */,                                 \
+                        /* varinit= */,                                 \
+                        VA_GROUP(varconst),                             \
+                        VA_GROUP(__VA_ARGS__))
+
+/* Macros below are complex, internal-use-only macros and should not be used directly. They are used by the
+ * macros above. */
+
+/* Integer increment at the preprocessor stage; each macro evaluates to the next integer. Overflow is not
+ * handled; f wraps to 0. */
+#define __VAI0 1
+#define __VAI1 2
+#define __VAI2 3
+#define __VAI3 4
+#define __VAI4 5
+#define __VAI5 6
+#define __VAI6 7
+#define __VAI7 8
+#define __VAI8 9
+#define __VAI9 a
+#define __VAIa b
+#define __VAIb c
+#define __VAIc d
+#define __VAId e
+#define __VAIe f
+#define __VAIf 0
+
+/* Integer increment carryover; all macros evaluate to 0 except f, which evaluates to 1. */
+#define __VAC0 0
+#define __VAC1 0
+#define __VAC2 0
+#define __VAC3 0
+#define __VAC4 0
+#define __VAC5 0
+#define __VAC6 0
+#define __VAC7 0
+#define __VAC8 0
+#define __VAC9 0
+#define __VACa 0
+#define __VACb 0
+#define __VACc 0
+#define __VACd 0
+#define __VACe 0
+#define __VACf 1
+
+/* Increment x based on carryover c. Requires x to be single hex digit (0-f) and carryover to be 0-1.
+ * Evaluates to 0 if x == f and c == 1, otherwise x+1 if c == 1, otherwise x. */
+#define ___VAI(x, c) ____VAI(x, c)
+#define ____VAI(x, c) ____VAI ## c(x)
+#define ____VAI0(x) x
+#define ____VAI1(x) __VAI ## x
+
+/* Carryover of x based on carryover c. Requires x to be single hex digit (0-f) and carryover to be
+ * 0-1. Evaluates to 1 if x is f and c is 1, otherwise 0. */
+#define ___VAC(x, c) ____VAC(x, c)
+#define ____VAC(x, c) ____VAC ## c(x)
+#define ____VAC0(x) 0
+#define ____VAC1(x) __VAC ## x
+
+/* Carryover of multiple digits. Each calculates the carryover of its digit, with 1 being the least
+ * significant digit, and 4 being the most significant digit. */
+#define ___VAC1(x1)             ___VAC(x1, 1)
+#define ___VAC2(x2, x1)         ___VAC(x2, ___VAC1(x1))
+#define ___VAC3(x3, x2, x1)     ___VAC(x3, ___VAC2(x2, x1))
+#define ___VAC4(x4, x3, x2, x1) ___VAC(x4, ___VAC3(x3, x2, x1))
+
+/* Increment with carryover across all digits. Each evaluate to their digit incremented if there is carryover
+ * from previous digits. */
+#define ___VAI1(x1)             ___VAI(x1, 1)
+#define ___VAI2(x2, x1)         ___VAI(x2, ___VAC1(x1))
+#define ___VAI3(x3, x2, x1)     ___VAI(x3, ___VAC2(x2, x1))
+#define ___VAI4(x4, x3, x2, x1) ___VAI(x4, ___VAC3(x3, x2, x1))
+
+/* Detect overflow. If all digits are f, this causes preprocessor error, otherwise this evaluates to
+ * nothing. */
+#define ___VAIO(x4, x3, x2, x1) ____VAIO(___VAC4(x4, x3, x2, x1))
+#define ____VAIO(c) _____VAIO(c)
+#define _____VAIO(c) ______VAIO ## c()
+#define ______VAIO0()
+#define ______VAIO1() _Pragma("GCC error \"VA increment overflow\"")
+
+/* Increment a 4-digit hex number. Requires pgroup to be a 4-digit hex number pgroup, e.g. (0,1,2,3)
+ * represents 0x0123. Evaluates to a 4-digit hex number pgroup that has been incremented by 1. On overflow, a
+ * preprocessor error is generated. */
+#define __VAINC4(pgroup) ___VAINC4 pgroup
+#define ___VAINC4(x4, x3, x2, x1)               \
+        ___VAIO(x4, x3, x2, x1)                 \
+        (___VAI4(x4, x3, x2, x1),               \
+         ___VAI3(x3, x2, x1),                   \
+         ___VAI2(x2, x1),                       \
+         ___VAI1(x1))
+
+/* Convert a 4-digit hex number pgroup to a standard hex number. Requires pgroup to be a 4-digit hex number
+ * pgroup. Evaluates to a standard hex number for the pgroup, e.g. (a,b,c,d) evalutes to 0xabcd. */
+#define __VANUM4(pgroup) ___VANUM4 pgroup
+#define ___VANUM4(x4, x3, x2, x1) 0x ## x4 ## x3 ## x2 ## x1
+
+/* Nested repeated evaluations. This is what controls when the 'toomany' VA_WRAP() parameter is evaluated. */
+#define __VA_EVAL_0x0002(...) __VA_ARGS__
+#define __VA_EVAL_0x0004(...) __VA_EVAL_0x0002(__VA_EVAL_0x0002(__VA_ARGS__))
+#define __VA_EVAL_0x0008(...) __VA_EVAL_0x0004(__VA_EVAL_0x0004(__VA_ARGS__))
+#define __VA_EVAL_0x0010(...) __VA_EVAL_0x0008(__VA_EVAL_0x0008(__VA_ARGS__))
+#define __VA_EVAL_0x0020(...) __VA_EVAL_0x0010(__VA_EVAL_0x0010(__VA_ARGS__))
+#define __VA_EVAL_0x0040(...) __VA_EVAL_0x0020(__VA_EVAL_0x0020(__VA_ARGS__))
+#define __VA_EVAL_0x0080(...) __VA_EVAL_0x0040(__VA_EVAL_0x0040(__VA_ARGS__))
+#define __VA_EVAL_0x0100(...) __VA_EVAL_0x0080(__VA_EVAL_0x0080(__VA_ARGS__))
+#define __VA_EVAL_0x0200(...) __VA_EVAL_0x0100(__VA_EVAL_0x0100(__VA_ARGS__))
+
+/* This should match the list of macros above. */
+#define __VA_EVAL_STEPS (0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080, 0x0100, 0x0200)
+
+/* Determine which __VA_EVAL_0x* macro to use for the given variadic args. This is a quick evaluation for the
+ * preprocessor and avoids unnecessary reevaluations for complex macro expansions. Evaluates to the smallest
+ * (least evaluations) __VA_EVAL_0x* macro token that can handle the number of provided variadic args. */
+#define __VA_EVAL_MACRO(...) __VA_EVAL_MACRO_CHECK_EACH(__VA_EVAL_STEPS, __VA_ARGS__)
+
+/* Re-evaluates for each step. If __VA_EVAL_STEPS is increased this may need to be increased. */
+#define __VA_EVAL_MACRO_CHECK_EACH(steps, ...) __VA_EVAL_MACRO_EVAL16(__VA_EVAL_MACRO_CHECK(steps, __VA_ARGS__))
+#define __VA_EVAL_MACRO_EVAL02(...) __VA_ARGS__
+#define __VA_EVAL_MACRO_EVAL04(...) __VA_EVAL_MACRO_EVAL02(__VA_EVAL_MACRO_EVAL02(__VA_ARGS__))
+#define __VA_EVAL_MACRO_EVAL08(...) __VA_EVAL_MACRO_EVAL04(__VA_EVAL_MACRO_EVAL04(__VA_ARGS__))
+#define __VA_EVAL_MACRO_EVAL16(...) __VA_EVAL_MACRO_EVAL08(__VA_EVAL_MACRO_EVAL08(__VA_ARGS__))
+
+/* Evaluates to the first __VA_EVAL_0x* macro name that can handle all the variadic args. If there are too
+ * many variadic args for the largest macro to handle, evaluates to nothing. Note this uses the same
+ * preprocessor recursion "trick" as __VA_WRAP_RECURSE() below. */
+#define __VA_EVAL_MACRO_CHECK(steps, ...)                               \
+        ___VA_EVAL_MACRO_CHECK                                          \
+        VA_PGROUP(__VA_EVAL_MACRO_MORE(VA_PGROUP_FIRST(steps), __VA_ARGS__))(steps, __VA_ARGS__)
+
+/* 'x' is the evaluation of __VA_EVAL_MACRO_MORE(); if it is empty, this evaluates to __VA_EVAL_MACRO_OK,
+ * otherwise the tested __VA_EVAL_0x* macro cannot handle all the variadic args, and this evaluates to
+ * __VA_EVAL_MACRO_NEXT. */
+#define ___VA_EVAL_MACRO_CHECK(x) VA_IF_ELSE(__VA_EVAL_MACRO_NEXT, __VA_EVAL_MACRO_OK, x)
+
+/* Move on to testing the next step (i.e. next 0x* value). */
+#define __VA_EVAL_MACRO_NEXT(steps, ...) ___VA_EVAL_MACRO_NEXT(VA_PGROUP_REST(steps), __VA_ARGS__)
+
+/* Test the next step value. If there are no more steps, evaluate to nothing. */
+#define ___VA_EVAL_MACRO_NEXT(steps, ...)                               \
+        VA_MACRO_IF(__VA_EVAL_MACRO_CHECK, VA_PGROUP_NOT_EMPTY(steps), steps, __VA_ARGS__)
+
+/* The first value of 'steps' is acceptable, so evaluate to the corresponding __VA_EVAL_* macro name. */
+#define __VA_EVAL_MACRO_OK(steps, ...) ___VA_EVAL_MACRO_OK(VA_PGROUP_FIRST(steps))
+#define ___VA_EVAL_MACRO_OK(n) ____VA_EVAL_MACRO_OK(n)
+#define ____VA_EVAL_MACRO_OK(n) __VA_EVAL_ ## n
+
+/* Bug in Centos Stream 8 gcc preprocessor doesn't correctly handle __VA_OPT__(); work around it. Once Centos
+ * Stream 8 is no longer supported, this can be dropped. */
+#define __CENTOS_STREAM_8_NONE
+#define __CENTOS_STREAM_8_BUG_CHECK() ___CENTOS_STREAM_8_BUG_CHECK(__CENTOS_STREAM_8_NONE)
+#define ___CENTOS_STREAM_8_BUG_CHECK(...) __VA_OPT__(1)
+#define __VA_EVAL_MACRO_MORE_IF_ONCE(...) __VA_OPT__(1)
+#define __VA_EVAL_MACRO_MORE_IF_TWICE(...) __VA_EVAL_MACRO_MORE_IF_ONCE(__VA_ARGS__)
+#define __VA_EVAL_MACRO_MORE_IF_MACRO()                 \
+        VA_IF_ELSE(__VA_EVAL_MACRO_MORE_IF_TWICE,       \
+                   __VA_EVAL_MACRO_MORE_IF_ONCE,        \
+                   __CENTOS_STREAM_8_BUG_CHECK())
+#define __VA_EVAL_MACRO_MORE_IF() __VA_EVAL_MACRO_MORE_IF_MACRO()
+
+/* Test if the __VA_EVAL_0x* macro for hex number 'n' can handle all the variadic args. Evaluates to 1 if
+ * there are remaining (unhandled) variadic args after all evaluations, otherwise nothing. */
+#define __VA_EVAL_MACRO_MORE(n, ...)                                    \
+        __VA_EVAL_MACRO_MORE_IF()(__VA_EVAL_MACRO_MORE_N(n)(__VA_OPT__(___VA_EVAL_MACRO_MORE(__VA_ARGS__))))
+#define __VA_EVAL_MACRO_MORE_N(n) __VA_EVAL_ ## n
+#define ___VA_EVAL_MACRO_MORE(v, ...) __VA_OPT__(___VA_EVAL_MACRO_MORE_NEXT VA_PGROUP()(__VA_ARGS__))
+#define ___VA_EVAL_MACRO_MORE_NEXT() ___VA_EVAL_MACRO_MORE
+
+/* Recursive macro evaluation. This is intended for use by VA_WRAP() above. This performs the actions
+ * described by VA_WRAP() for each variadic arg.
+ *
+ * This "trick" inspired by:
+ *   https://www.scs.stanford.edu/~dm/blog/va-opt.html
+ *   https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,-tips,-and-idioms
+ *
+ * This determines the number of re-evaluations required for the provided number of variadic args, then calls
+ * the appropriate __VA_EVAL_0x*() macro with ___VA_WRAP_RECURSE(), providing the initial index of 0x0001. */
+#define __VA_WRAP_RECURSE(macro, separator, context, zero, toomany, ...) \
+        VA_IF_ELSE(__VA_WRAP_RECURSE_NONZERO,                           \
+                   __VA_WRAP_RECURSE_ZERO,                              \
+                   __VA_ARGS__)(macro, separator, context, zero, toomany, __VA_ARGS__)
+#define __VA_WRAP_RECURSE_ZERO(macro, separator, context, zero, toomany, ...) zero(context)
+#define __VA_WRAP_RECURSE_NONZERO(macro, separator, context, zero, toomany, ...) \
+        __VA_WRAP_RECURSE_CHECK_TOOMANY(__VA_EVAL_MACRO(__VA_ARGS__),   \
+                                        macro, separator, context, toomany, __VA_ARGS__)
+#define __VA_WRAP_RECURSE_CHECK_TOOMANY(evalmacro, macro, separator, context, toomany, ...) \
+        VA_IF_ELSE(__VA_WRAP_RECURSE_EVAL,                              \
+                   __VA_WRAP_RECURSE_TOOMANY,                           \
+                   evalmacro)(evalmacro, macro, separator, context, toomany, __VA_ARGS__)
+#define __VA_WRAP_RECURSE_TOOMANY(evalmacro, macro, separator, context, toomany, ...) toomany(context)
+#define __VA_WRAP_RECURSE_EVAL(evalmacro, macro, separator, context, toomany, ...) \
+        evalmacro(___VA_WRAP_RECURSE(macro,                             \
+                                     separator,                         \
+                                     context,                           \
+                                     (0,0,0,1),                         \
+                                     __VA_ARGS__))
+
+/* This is the "trick" macro, which evaluates to the current variadic arg 'value' wrapped by 'macro', and
+ * then (if there are remaining variadic args) followed by 'separator' followed by the "trick"; which is
+ * ___VA_WRAP_NEXT token and VA_PGROUP(). On the next re-evaluation, this (indirectly) evaluates recursively
+ * to ___VA_WRAP_RECURSE(). */
+#define ___VA_WRAP_RECURSE(macro, separator, context, index, value, ...) \
+        ___VA_WRAP_RECURSE_CALL(macro,                                  \
+                                VA_IF_ELSE(separator, VA_NOOP, __VA_ARGS__), \
+                                VA_GROUP(context, __VANUM4(index), value, __VA_ARGS__)) \
+        __VA_OPT__(___VA_WRAP_NEXT VA_PGROUP()(macro, separator, context, __VAINC4(index), __VA_ARGS__))
+#define ___VA_WRAP_RECURSE_CALL(macro, separator, args) macro(args)separator(args)
+#define ___VA_WRAP_NEXT() ___VA_WRAP_RECURSE

src/test/meson.build

@@ -186,6 +186,7 @@ simple_tests += files(
         'test-user-record.c',
         'test-user-util.c',
         'test-utf8.c',
+        'test-variadic.c',
         'test-verbs.c',
         'test-vpick.c',
         'test-web-util.c',

src/test/test-variadic.c

@@ -0,0 +1,726 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stddef.h>
+
+#include "log.h"
+#include "string-util.h"
+#include "tests.h"
+#include "variadic-fundamental.h"
+
+#define _MACRO_LOG(...) ({ log_info("%s", #__VA_ARGS__); 0; })
+#define MACRO_LOG(...) _MACRO_LOG(__VA_ARGS__)
+
+#define NONE
+#define MACRO_NONE()
+#define MACRO_IGNORE(...)
+
+#define MACRO1(x, ...) (x)
+#define MACRO2(x1, x2, ...) (x2)
+#define MACRO_SUM12(x1, x2, ...) (x1 + x2)
+
+#define MACRO_3ARG_SUM(x1, x2, x3) x1 + x2 + x3
+#define MACRO_4ARG_SUM(x1, x2, x3, x4) x1 + x2 + x3 + x4
+
+#define MACRO_VARG_1(x1, ...) x1
+#define MACRO_VARG_2(x1, ...) MACRO_VARG_1(__VA_ARGS__)
+#define MACRO_VARG_3(x1, ...) MACRO_VARG_2(__VA_ARGS__)
+#define MACRO_VARG_4(x1, ...) MACRO_VARG_3(__VA_ARGS__)
+
+#define MACRO_GROUP_VARG_1(x) MACRO_VARG_1(x)
+#define MACRO_GROUP_VARG_2(x) MACRO_VARG_2(x)
+#define MACRO_GROUP_VARG_3(x) MACRO_VARG_3(x)
+#define MACRO_GROUP_VARG_4(x) MACRO_VARG_4(x)
+
+#define MACRO_GROUP_3ARG_SUM(x) MACRO_3ARG_SUM(x)
+#define MACRO_GROUP_4ARG_SUM(x) MACRO_4ARG_SUM(x)
+
+#define MACRO_2GROUP_4ARG_3ARG_SUM(g1, g2) MACRO_4ARG_SUM(g1) + MACRO_3ARG_SUM(g2)
+#define MACRO_2GROUP_VARG_3ARG_G2A2(g1, g2) MACRO_VARG_2(g2)
+#define MACRO_2GROUP_4ARG_VARG_SUM_G1A4_G2A3(g1, g2) MACRO_VARG_4(g1) + MACRO_VARG_3(g2)
+
+TEST(va_group) {
+        assert_se(MACRO_GROUP_VARG_4(VA_GROUP(1,2,3,4)) == 4);
+        assert_se(MACRO_GROUP_VARG_1(VA_GROUP(5,10,20)) == 5);
+        assert_se(MACRO_GROUP_3ARG_SUM(VA_GROUP(1, 1000, -2)) == 999);
+        assert_se(MACRO_GROUP_4ARG_SUM(VA_GROUP(1, 1, 1, 2)) == 5);
+        assert_se(MACRO_2GROUP_4ARG_3ARG_SUM(VA_GROUP(5,6,7,8), VA_GROUP(1,1,1)) == 29);
+        assert_se(MACRO_2GROUP_VARG_3ARG_G2A2(VA_GROUP(1,2,3,4,5,6,7,8,9), VA_GROUP(3,2,1)) == 2);
+        assert_se(MACRO_2GROUP_4ARG_VARG_SUM_G1A4_G2A3(VA_GROUP(4,3,2,1), VA_GROUP(9,8,7,6,5,4)) == 8);
+}
+
+#define V1() 1
+#define V2() 2
+
+#define VI6E7(x) VA_IF_ELSE(6, 7, x)
+#define VI8E9(x) VA_IF_ELSE(8, 9, x)
+
+TEST(va_if_else) {
+        assert_se(VA_IF_ELSE(1,2) == 2);
+        assert_se(VA_IF_ELSE(1,2,) == 2);
+        assert_se(VA_IF_ELSE(1,2, ) == 2);
+        assert_se(VA_IF_ELSE(1,2,NONE) == 2);
+        assert_se(VA_IF_ELSE(1,2, NONE) == 2);
+        assert_se(VA_IF_ELSE(1,2,,) == 1);
+        assert_se(VA_IF_ELSE(1, 2, ) == 2);
+        assert_se(VA_IF_ELSE(1, 2,NONE ) == 2);
+        assert_se(VA_IF_ELSE(1, 2, 1) == 1);
+        assert_se(VA_IF_ELSE(1, 2,  "no") == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF(1, )) == 2);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF(1, 1) ) == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_NOT(1, )) == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_NOT(1, 2)) == 2);
+        assert_se(VA_IF_ELSE(1, 2, VA_NOT()) == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_NOT(1)) == 2);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_ELSE(100, 200, )) == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_ELSE(100, 200, 1)) == 1);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_ELSE(100, , )) == 2);
+        assert_se(VA_IF_ELSE(1, 2, VA_IF_ELSE(, 4 , )) == 1);
+        assert_se(VA_IF_ELSE(V1, V2, 1)() == 1);
+        assert_se(VA_IF_ELSE(V1, V2, )() == 2);
+        assert_se(VA_IF_ELSE(VI6E7, VI8E9, )(1) == 8);
+        assert_se(VA_IF_ELSE(VI6E7, VI8E9, 0)(1) == 6);
+        assert_se(VA_IF_ELSE(VI6E7, VI8E9, )() == 9);
+        assert_se(VA_IF_ELSE(VI6E7, VI8E9, 55)() == 7);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4,  ), VA_IF_ELSE(5, 6,  ),  ) == 6);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4,  ), VA_IF_ELSE(5, 6,  ), 1) == 4);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4,  ), VA_IF_ELSE(5, 6, 1),  ) == 5);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4,  ), VA_IF_ELSE(5, 6, 1), 1) == 4);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4, 1), VA_IF_ELSE(5, 6,  ),  ) == 6);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4, 1), VA_IF_ELSE(5, 6,  ), 1) == 3);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4, 1), VA_IF_ELSE(5, 6, 1),  ) == 5);
+        assert_se(VA_IF_ELSE(VA_IF_ELSE(3, 4, 1), VA_IF_ELSE(5, 6, 1), 1) == 3);
+}
+
+TEST(va_if) {
+        assert_se(VA_IF(123,1) == 123);
+        assert_se(VA_IF(1+,1) 0 == 1);
+        assert_se(VA_IF(1+,0) 0 == 1);
+        assert_se(VA_IF(1+,) 0 == 0);
+        assert_se(VA_IF(1+,  )0 == 0);
+        assert_se(VA_IF(1+, VA_IF(2+, VA_IF(3+, 4))) 0 == 1);
+        assert_se(VA_IF(1+, VA_IF(2+, VA_IF(3+, ))) 0 == 0);
+        assert_se(VA_IF(1+, VA_IF(, VA_IF(3+, 4))) 0 == 0);
+        assert_se(streq(VA_IF("hi", VA_IF(x,1)) "", "hi"));
+        assert_se(!streq(VA_IF("hi", VA_IF(x,NONE)) "", "hi"));
+}
+
+TEST(va_if_not) {
+        assert_se(VA_IF_NOT(123,) == 123);
+        assert_se(VA_IF_NOT(1+,1) 0 == 0);
+        assert_se(VA_IF_NOT(1+,0) 0 == 0);
+        assert_se(VA_IF_NOT(1+,) 0 == 1);
+        assert_se(VA_IF_NOT(1+,  )0 == 1);
+        assert_se(VA_IF_NOT(1+, VA_IF_NOT(2+, VA_IF_NOT(3+, 4))) 0 == 0);
+        assert_se(VA_IF_NOT(1+, VA_IF_NOT(2+, VA_IF_NOT(3+, ))) 0 == 1);
+        assert_se(VA_IF_NOT(1+, VA_IF_NOT(, VA_IF_NOT(3+, 4))) 0 == 1);
+        assert_se(!streq(VA_IF_NOT("hi", 1) "", "hi"));
+        assert_se(streq(VA_IF_NOT("hi", NONE) "", "hi"));
+}
+
+TEST(va_not) {
+        assert_se(streq(STRINGIFY(VA_NOT()), "1"));
+        assert_se(streq(STRINGIFY(VA_NOT(  )), "1"));
+        assert_se(streq(STRINGIFY(VA_NOT(1)), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(0)), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(1,2,3)), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(,1,)), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(,1)), ""));
+        assert_se(streq(STRINGIFY(VA_NOT("")), ""));
+        assert_se(streq(STRINGIFY(VA_NOT("hi")), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT())), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT(2))), "1"));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT("hi"))), "1"));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT(VA_NOT(2)))), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT(2),VA_NOT(3))), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT(),VA_NOT(3))), ""));
+        assert_se(streq(STRINGIFY(VA_NOT(VA_NOT(2),VA_NOT())), ""));
+}
+
+TEST(va_first) {
+        assert_se(VA_FIRST(1,2,3) == 1);
+        assert_se(VA_FIRST(1+,2+) 0 == 1);
+        assert_se(VA_FIRST(1+) 0 == 1);
+        assert_se(VA_FIRST() 0 == 0);
+        assert_se(streq(STRINGIFY(VA_FIRST()), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST( )), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST(,)), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST(NONE)), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST( NONE )), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST( NONE, )), ""));
+        assert_se(streq(STRINGIFY(VA_FIRST( NONE,1,3 )), ""));
+}
+
+TEST(va_rest) {
+        assert_se(VA_REST(1,3) == 3);
+        assert_se(VA_REST(1+,2+) 0 == 2);
+        assert_se(VA_REST(1+) 0 == 0);
+        assert_se(VA_REST() 0 == 0);
+        assert_se(streq(STRINGIFY(VA_REST(NONE,1)), "1"));
+        assert_se(streq(STRINGIFY(VA_REST(1,NONE,1)), ",1"));
+        assert_se(streq(STRINGIFY(VA_REST(1,NONE)), ""));
+
+        assert_se(VA_FIRST(VA_REST(1,2,3,4,5)) == 2);
+
+        int ia[] = { VA_REST(1,2,3,4,5) };
+        assert_se(ELEMENTSOF(ia) == 4);
+        assert_se(ia[0] == 2);
+        assert_se(ia[1] == 3);
+        assert_se(ia[2] == 4);
+        assert_se(ia[3] == 5);
+}
+
+TEST(va_comma) {
+        assert_se(streq("0 , 1, 2", STRINGIFY(0 VA_COMMA(0) 1, 2)));
+        assert_se(streq("0 , 1, 2", STRINGIFY(0 VA_COMMA(1) 1, 2)));
+        assert_se(streq("0 1, 2", STRINGIFY(0 VA_COMMA() 1, 2)));
+}
+
+TEST(va_and) {
+        assert_se(streq(STRINGIFY(VA_AND(1,2)), "1"));
+        assert_se(streq(STRINGIFY(VA_AND(,2)), ""));
+        assert_se(streq(STRINGIFY(VA_AND(1,)), ""));
+        assert_se(streq(STRINGIFY(VA_AND(,)), ""));
+        assert_se(streq(STRINGIFY(VA_AND(  ,  )), ""));
+        assert_se(streq(STRINGIFY(VA_AND(1  ,  )), ""));
+        assert_se(streq(STRINGIFY(VA_AND(  , 2 )), ""));
+        assert_se(streq(STRINGIFY(VA_AND(  1  , 2 )), "1"));
+        assert_se(streq(STRINGIFY(VA_AND("hi",2)), "1"));
+        assert_se(streq(STRINGIFY(VA_AND(1,"hi")), "1"));
+        assert_se(streq(STRINGIFY(VA_AND("hi","hi")), "1"));
+        assert_se(streq(STRINGIFY(VA_AND(VA_AND(1,2),2)), "1"));
+        assert_se(streq(STRINGIFY(VA_AND(VA_AND(1,),2)), ""));
+        assert_se(streq(STRINGIFY(VA_AND(VA_AND(1,2),)), ""));
+        assert_se(streq(STRINGIFY(VA_AND( VA_AND(  , 1 )  ,  VA_AND(  ,  )  )), ""));
+        assert_se(streq(STRINGIFY(VA_AND( VA_AND(  ,  )  ,  VA_AND(  ,  )  )), ""));
+}
+
+TEST(va_or) {
+        assert_se(streq(STRINGIFY(VA_OR(1,2)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(,2)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(1,)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(,)), ""));
+        assert_se(streq(STRINGIFY(VA_OR("hi",2)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(1,"hi")), "1"));
+        assert_se(streq(STRINGIFY(VA_OR("hi","hi")), "1"));
+        assert_se(streq(STRINGIFY(VA_OR("hi",)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(,"hi")), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(  ,  )), ""));
+        assert_se(streq(STRINGIFY(VA_OR(VA_OR(1,),)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(VA_OR(,),)), ""));
+        assert_se(streq(STRINGIFY(VA_OR(VA_OR(,),2)), "1"));
+        assert_se(streq(STRINGIFY(VA_OR(  VA_OR(1,)  ,  )), "1"));
+        assert_se(streq(STRINGIFY(VA_OR( VA_OR(  , 1 )  ,  VA_OR(  ,  )  )), "1"));
+        assert_se(streq(STRINGIFY(VA_OR( VA_OR(  ,  )  ,  VA_OR(  ,  )  )), ""));
+}
+
+TEST(va_macro) {
+        assert_se(VA_MACRO(MACRO1, 3,2,1) == 3);
+        assert_se(VA_MACRO(MACRO1, 4) == 4);
+        assert_se(VA_MACRO(MACRO2, 4,5) == 5);
+        assert_se(streq(VA_MACRO(MACRO2, 4,"hi"), "hi"));
+}
+
+#define VA_NARGS_MAX_LESS_1                                             \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,010,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,020,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,030,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,040,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,050,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,060,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,070,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,080,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,090,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0a0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0b0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0c0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0d0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0e0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,0f0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,100,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,110,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,120,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,130,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,140,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,150,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,160,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,170,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,180,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,190,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1a0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1b0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1c0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1d0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1e0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,1f0,                              \
+        1,2,3,4,5,6,7,8,9,a,b,c,d,e,  1ff
+
+#define TEST_EQ_STR(expected, result) assert_se(streq(expected, STRINGIFY(result)))
+
+#define XvX(c, i, v, ...) X v X
+
+TEST(va_macro_foreach) {
+        TEST_EQ_STR("", VA_MACRO_FOREACH(XvX));
+        TEST_EQ_STR("", VA_MACRO_FOREACH(XvX,));
+        TEST_EQ_STR("", VA_MACRO_FOREACH(XvX, ));
+        TEST_EQ_STR("X 1 X", VA_MACRO_FOREACH(XvX, 1));
+        TEST_EQ_STR("X 1 X, X 2 X", VA_MACRO_FOREACH(XvX, 1, 2));
+        TEST_EQ_STR("X hi X", VA_MACRO_FOREACH(XvX, hi));
+        TEST_EQ_STR("X one X, X two X, X three X", VA_MACRO_FOREACH(XvX, one, two, three));
+        TEST_EQ_STR("X 1 X, X 2 X, X X, X 4 X, X 5 X", VA_MACRO_FOREACH(XvX, 1, 2, , 4, 5));
+        TEST_EQ_STR("X X, X 2 X, X 3 X, X 4 X, X 5 X", VA_MACRO_FOREACH(XvX, , 2, 3, 4, 5));
+
+        /* Note that if the final arg is empty (or only whitespace), it is not included. */
+        TEST_EQ_STR("X 1 X", VA_MACRO_FOREACH(XvX, 1,));
+        TEST_EQ_STR("X X, X 1 X", VA_MACRO_FOREACH(XvX, ,1));
+        TEST_EQ_STR("X 1 X", VA_MACRO_FOREACH(XvX, 1, ));
+        TEST_EQ_STR("X X, X 1 X", VA_MACRO_FOREACH(XvX,,1));
+        TEST_EQ_STR("X X, X 1 X", VA_MACRO_FOREACH(XvX,,1,));
+        TEST_EQ_STR("X X, X 1 X", VA_MACRO_FOREACH(XvX,,1, ));
+        TEST_EQ_STR("X X, X X, X X, X X", VA_MACRO_FOREACH(XvX, , , , , ));
+        TEST_EQ_STR("X X, X X, X X, X X, X 1 X", VA_MACRO_FOREACH(XvX, , , , , 1));
+        TEST_EQ_STR("X X, X X, X X, X X, X 1 X", VA_MACRO_FOREACH(XvX, , , , ,1));
+        TEST_EQ_STR("X X, X X, X X, X X", VA_MACRO_FOREACH(XvX,,,,,));
+        TEST_EQ_STR("X X, X X, X X, X X, X 1 X", VA_MACRO_FOREACH(XvX,,,,,1));
+        TEST_EQ_STR("X X, X X, X X, X X, X 1 X", VA_MACRO_FOREACH(XvX,,,,, 1));
+}
+
+TEST(va_filter) {
+        TEST_EQ_STR("0, 1, 2, 3, hi, later", VA_FILTER(0, 1, 2, 3, , , , hi, later, ));
+        TEST_EQ_STR("", VA_FILTER(, , , , ,));
+        TEST_EQ_STR("5", VA_FILTER(, , , , ,5));
+        TEST_EQ_STR("4, 5", VA_FILTER(4, , , , ,5));
+        TEST_EQ_STR("6, 7", VA_FILTER(, 6, 7, , ,));
+        TEST_EQ_STR("\"one\", \"two\"", VA_FILTER(, "one", ,"two" , ,));
+}
+
+#define TEST_NARGS(expect, expect_token, ...)                           \
+        ({                                                              \
+                assert_se(VA_NARGS(__VA_ARGS__) == expect);             \
+                assert_se(streq(STRINGIFY(expect_token), STRINGIFY(VA_NARGS(__VA_ARGS__)))); \
+                assert_se(__builtin_constant_p(VA_NARGS(__VA_ARGS__))); \
+        })
+
+TEST(va_nargs) {
+        _unused_ int i = 0;
+        _unused_ const char *hi = "hello";
+
+        TEST_NARGS(0, 0x0000);
+        TEST_NARGS(0, 0x0000,);
+        TEST_NARGS(0, 0x0000, );
+        TEST_NARGS(1, 0x0001, 1);
+        TEST_NARGS(1, 0x0001, "hello");
+        TEST_NARGS(1, 0x0001, "hello");
+        TEST_NARGS(1, 0x0001, i);
+        TEST_NARGS(1, 0x0001, i++);
+        TEST_NARGS(2, 0x0002, i, hi);
+        TEST_NARGS(16, 0x0010, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
+}
+
+TEST(va_last) {
+        _unused_ int i = 0;
+        _unused_ const char *hi = "hello";
+
+        assert_se(streq(STRINGIFY(VA_LAST()), ""));
+        assert_se(VA_LAST(1,2,10) == 10);
+        assert_se(streq(VA_LAST("hi", "there"), "there"));
+        assert_se(VA_LAST(1,2,i++) == 0);
+        assert_se(i == 1);
+        assert_se(VA_LAST(1,2,++i) == 2);
+        assert_se(i == 2);
+        assert_se(VA_LAST(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) == 15);
+        assert_se(VA_LAST(VA_NARGS_MAX_LESS_1,123) == 123);
+}
+
+TEST(va_declarations) {
+        int i = 999;
+        VA_DECLARATIONS(test_decl, int, char*, uint64_t, typeof(i));
+
+        test_decl_0x0001 = 10;
+        test_decl_0x0002 = (char*)"hello";
+        test_decl_0x0003 = 0xffff000000000001;
+        test_decl_0x0004 = 8;
+        assert_se(test_decl_0x0001 == 10);
+        assert_se(__builtin_types_compatible_p(typeof(test_decl_0x0001), int));
+        assert_se(streq(test_decl_0x0002, "hello"));
+        assert_se(__builtin_types_compatible_p(typeof(test_decl_0x0002), char*));
+        assert_se(test_decl_0x0003 == 0xffff000000000001);
+        assert_se(__builtin_types_compatible_p(typeof(test_decl_0x0003), uint64_t));
+        assert_se(test_decl_0x0004 == 8);
+        assert_se(__builtin_types_compatible_p(typeof(test_decl_0x0004), int));
+
+        VA_DECLARATIONS();
+
+        VA_INITIALIZED_DECLARATIONS(test_i, test_decl_0x0003, test_decl_0x0004, i, test_decl_0x0002, test_decl_0x0001, i);
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0001), uint64_t));
+        assert_se(test_i_0x0001 == 0xffff000000000001);
+        test_i_0x0001--;
+        assert_se(test_i_0x0001 == 0xffff000000000000);
+        assert_se(test_decl_0x0003 == 0xffff000000000001);
+        test_decl_0x0003 = 0xffff;
+        assert_se(test_i_0x0001 == 0xffff000000000000);
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0002), int));
+        assert_se(test_i_0x0002 == 8);
+        test_i_0x0002--;
+        assert_se(test_i_0x0002 == 7);
+        assert_se(test_decl_0x0004 == 8);
+        test_decl_0x0004 = 50;
+        assert_se(test_i_0x0002 == 7);
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0003), int));
+        assert_se(test_i_0x0003 == 999);
+        test_i_0x0003--;
+        assert_se(test_i_0x0003 == 998);
+        assert_se(i == 999);
+        i = 333;
+        assert_se(test_i_0x0003 == 998);
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0004), char*));
+        assert_se(streq(test_i_0x0004, "hello"));
+        assert_se(streq(test_i_0x0004, test_decl_0x0002));
+        test_i_0x0004 = NULL;
+        assert_se(test_i_0x0004 == NULL);
+        assert_se(streq(test_decl_0x0002, "hello"));
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0005), int));
+        assert_se(test_i_0x0005 == 10);
+        test_i_0x0005--;
+        assert_se(test_i_0x0005 == 9);
+        assert_se(test_decl_0x0001 == 10);
+        test_decl_0x0001 = 44;
+        assert_se(test_i_0x0005 == 9);
+
+        assert_se(__builtin_types_compatible_p(typeof(test_i_0x0006), int));
+        assert_se(test_i_0x0006 == 999);
+        test_i_0x0006--;
+        assert_se(test_i_0x0006 == 998);
+        assert_se(i == 333);
+        i = 222;
+        assert_se(test_i_0x0006 == 998);
+
+        VA_INITIALIZED_DECLARATIONS();
+}
+
+#define TEST_TOKENS(equal1, equal2, equal3, equal4,                     \
+                    expect1, expect2, expect3, expect4,                 \
+                    v1, v2, v3, v4)                                     \
+        ({                                                              \
+                assert_se((expect1 == v1) == equal1);                   \
+                assert_se((expect2 == v2) == equal2);                   \
+                assert_se((expect3 == v3) == equal3);                   \
+                assert_se((expect4 == v4) == equal4);                   \
+        })
+
+TEST(va_tokens) {
+        int i1 = 10, i2 = 100, i3 = 50, i4 = 99;
+
+        VA_INITIALIZED_DECLARATIONS(test_i_, i1, i2, i3, i4);
+
+        VA_MACRO(TEST_TOKENS, true, true, true, true, i1, i2, i3, i4, VA_TOKENS(test_i_, i1, i2, i3, i4));
+        VA_MACRO(TEST_TOKENS, true, true, true, true, 10, 100, i3, 99, VA_TOKENS(test_i_, i1, i2, i3, i4));
+
+        /* VA_TOKENS() doesn't actually use the variadic args, the tokens are based on index */
+        VA_MACRO(TEST_TOKENS, true, true, true, true, i1, i2, i3, i4, VA_TOKENS(test_i_, x, x, x, x));
+
+        VA_MACRO(TEST_TOKENS, true, false, true, false, i1, i4, i3, 1234, VA_TOKENS(test_i_, i1, i2, i3, i4));
+}
+
+#define TEST_UNIQ(x, y, z)                      \
+        _unused_ int x = 10;                    \
+        _unused_ const char *y = "hi";          \
+        _unused_ uint64_t z = 0xffff;
+
+TEST(va_uniq) {
+        int x = 20;
+        const char *y = "still me";
+        uint64_t z = 0xf;
+
+        VA_MACRO(TEST_UNIQ, VA_UNIQ(first, second, third));
+
+        assert_se(x == 20);
+        assert_se(streq(y, "still me"));
+        assert_se(z == 0xf);
+}
+
+#define TEST_MACRO_SWAP(tmp, x, y)              \
+        ({                                      \
+                tmp = x;                        \
+                x = y;                          \
+                y = tmp;                        \
+        })
+
+#define TEST_MACRO_ALL(u1, u2, v1, v2, vi1, vi2, vc1, vc2, d1, d2)      \
+        ({                                                              \
+                int u1 = 100;                                           \
+                char *u2 = (char*)"u2";                                 \
+                assert_se(u1 == 100);                                   \
+                assert_se(streq(u2, "u2"));                             \
+                                                                        \
+                v1 = d1;                                                \
+                v2 = d2;                                                \
+                assert_se(v1 == 30);                                    \
+                assert_se(streq(v2, "d2"));                             \
+                v1++;                                                   \
+                v2++;                                                   \
+                assert_se(v1 == 31);                                    \
+                assert_se(streq(v2, "2"));                              \
+                                                                        \
+                assert_se(vi1 == 10);                                   \
+                assert_se(streq(vi2, "vi2"));                           \
+                vi1++;                                                  \
+                vi2++;                                                  \
+                assert_se(vi1 == 11);                                   \
+                assert_se(streq(vi2, "i2"));                            \
+                                                                        \
+                assert_se(vc1 == 20);                                   \
+                assert_se(streq(vc2, "vc2"));                           \
+                                                                        \
+                assert_se(d1 == 30);                                    \
+                assert_se(streq(d2, "d2"));                             \
+                                                                        \
+                d1 = u1;                                                \
+                d2 = u2;                                                \
+                assert_se(d1 == 100);                                   \
+                assert_se(streq(d2, "u2"));                             \
+                                                                        \
+                d1 + 1000;                                              \
+        })
+
+TEST(va_macro_helper) {
+        int i1, i2;
+
+        i1 = 10;
+        i2 = 20;
+        VA_MACRO_HELPER(TEST_MACRO_SWAP,
+                        /*uniq*/,
+                        int,
+                        /*varinit*/,
+                        /*varconst*/,
+                        VA_GROUP(i1, i2));
+        assert_se(i1 == 20);
+        assert_se(i2 == 10);
+
+        int vi1 = 10, vc1 = 20, d1 = 30;
+        char *vi2 = (char*)"vi2", *vc2 = (char*)"vc2", *d2 = (char*)"d2";
+        int all = VA_MACRO_HELPER(TEST_MACRO_ALL,
+                                  VA_GROUP(u1, u2),
+                                  VA_GROUP(int, char*),
+                                  VA_GROUP(vi1, vi2),
+                                  VA_GROUP(vc1, vc2),
+                                  VA_GROUP(d1, d2));
+        assert_se(all == 1100);
+        assert_se(vi1 == 10);
+        assert_se(streq(vi2, "vi2"));
+        assert_se(vc1 == 20);
+        assert_se(streq(vc2, "vc2"));
+        assert_se(d1 == 100);
+        assert_se(streq(d2, "u2"));
+}
+
+#define TEST_UNIQ_INT_X(_x)                     \
+        ({                                      \
+                int _x = 5;                     \
+                _x++;                           \
+        })
+
+#define TEST_UNIQ_INT_X_Y_Z(x, y, z, v, ...)            \
+        ({                                              \
+                int x = v;                              \
+                int y = VA_IF_ELSE(VA_FIRST(__VA_ARGS__), 100, __VA_ARGS__); \
+                int z = VA_IF_ELSE(VA_FIRST(VA_REST(__VA_ARGS__)), 2000, VA_REST(__VA_ARGS__)); \
+                x + y + z;                              \
+        })
+
+TEST(va_macro_uniq) {
+        int x = 1, _x = 2;
+
+        int y = VA_MACRO_UNIQ(TEST_UNIQ_INT_X, _x);
+        assert_se(x == 1);
+        assert_se(_x == 2);
+        assert_se(y == 5);
+
+        int z = VA_MACRO_UNIQ(TEST_UNIQ_INT_X_Y_Z, VA_GROUP(x, y, z), x);
+        assert_se(x == 1);
+        assert_se(_x == 2);
+        assert_se(y == 5);
+        assert_se(z == 2101);
+
+        _x = VA_MACRO_UNIQ(TEST_UNIQ_INT_X_Y_Z, VA_GROUP(1, 2, z), 99);
+        assert_se(x == 1);
+        assert_se(_x == 2199);
+        assert_se(y == 5);
+        assert_se(z == 2101);
+
+        z = VA_MACRO_UNIQ(TEST_UNIQ_INT_X_Y_Z, VA_GROUP(_X, _Y, _Z), 5, 20);
+        assert_se(x == 1);
+        assert_se(_x == 2199);
+        assert_se(y == 5);
+        assert_se(z == 2025);
+
+        z = VA_MACRO_UNIQ(TEST_UNIQ_INT_X_Y_Z, VA_GROUP(_X, _Y, _Z), 7, 70, 5000);
+        assert_se(x == 1);
+        assert_se(_x == 2199);
+        assert_se(y == 5);
+        assert_se(z == 5077);
+}
+
+#define TEST_MACRO_INT_CHARP(x1, x2)                                    \
+        ({                                                              \
+                assert_se(__builtin_types_compatible_p(typeof(x1), int)); \
+                assert_se(__builtin_types_compatible_p(typeof(x2), char*)); \
+        })
+
+typedef struct { int a; } structabc;
+
+#define TEST_MACRO_INTP_STRUCTABC_INT(x1, x2, x3)                       \
+        ({                                                              \
+                assert_se(__builtin_types_compatible_p(typeof(x1), int*)); \
+                assert_se(__builtin_types_compatible_p(typeof(x2), structabc)); \
+                assert_se(__builtin_types_compatible_p(typeof(x3), int)); \
+        })
+
+#define TEST_MACRO_INT_TMP1(x)                  \
+        ({                                      \
+                x = 7;                          \
+                x++;                            \
+        })
+
+TEST(va_macro_var) {
+        int j = VA_MACRO_VAR(TEST_MACRO_INT_TMP1, int);
+        assert_se(j == 7);
+
+        assert_se(VA_MACRO_VAR(TEST_MACRO_INT_TMP1, int) == 7);
+
+        VA_MACRO_VAR(TEST_MACRO_INT_CHARP, VA_GROUP(int, char*));
+        VA_MACRO_VAR(TEST_MACRO_INTP_STRUCTABC_INT, VA_GROUP(int*, structabc, int));
+}
+
+#define MACRO_USE_TWICE_1L2_OR_B0(x1, x2)               \
+        ({                                              \
+                (x1 < x2) || (x1 == 0 && x2 == 0);      \
+        })
+
+#define MACRO_INT_USE_ARGS1_EVAL1(x1)                   \
+        ({                                              \
+                _unused_ int x = x1;                    \
+                x1;                                     \
+        })
+
+#define MACRO_INT_USE_ARGS2_EVAL1(x1,x2)                \
+        ({                                              \
+                _unused_ int x = x1 + x2;               \
+                x1;                                     \
+        })
+
+#define MACRO_INT_USE_ARGS2_EVAL2(x1,x2)                \
+        ({                                              \
+                _unused_ int x = x1 + x2;               \
+                x2;                                     \
+        })
+
+#define MACRO_INT_USE_ARGS6_EVAL1(x1,x2,x3,x4,x5,x6)            \
+        ({                                                      \
+                _unused_ int x = x1 + x2 + x3 + x4 + x5 + x6;   \
+                x1;                                             \
+        })
+
+#define MACRO_INT_USE_ARGS6_EVAL4(x1,x2,x3,x4,x5,x6)            \
+        ({                                                      \
+                _unused_ int x = x1 + x2 + x3 + x4 + x5 + x6;   \
+                x4;                                             \
+        })
+
+TEST(va_macro_varinit) {
+        _unused_ int i = 1, j = 0, k = 5678;
+
+        assert_se(VA_MACRO_VARINIT(MACRO_INT_USE_ARGS1_EVAL1, 1) == 1);
+        assert_se(VA_MACRO_VARINIT(MACRO_INT_USE_ARGS2_EVAL1, VA_GROUP(1, 10)) == 1);
+        assert_se(VA_MACRO_VARINIT(MACRO_INT_USE_ARGS2_EVAL2, VA_GROUP(1, 10)) == 10);
+        assert_se(VA_MACRO_VARINIT(MACRO_INT_USE_ARGS6_EVAL1, VA_GROUP(100, 1000, 1, 0, 20, -80)) == 100);
+        assert_se(VA_MACRO_VARINIT(MACRO_INT_USE_ARGS6_EVAL4, VA_GROUP(-9,i,1,k,3,4)) == 5678);
+        assert_se(VA_MACRO_VARINIT(MACRO_SUM12, VA_GROUP(1,10)) == 11);
+        assert_se(VA_MACRO_VARINIT(MACRO_SUM12, VA_GROUP(10,k)) == 5688);
+
+        i = 1234;
+        assert_se(VA_MACRO_VARINIT(MACRO1, i) == 1234);
+        assert_se(VA_MACRO_VARINIT(MACRO1, 1234) == i);
+
+        i = 10;
+        j = 20;
+        assert_se(VA_MACRO_VARINIT(MACRO_USE_TWICE_1L2_OR_B0, VA_GROUP(i++, j--)) == 1);
+        assert_se(i == 11);
+        assert_se(j == 19);
+
+        assert_se(VA_MACRO_VARINIT(MACRO_USE_TWICE_1L2_OR_B0, VA_GROUP(j + 5, j + 10)) == 1);
+        assert_se(i == 11);
+        assert_se(j == 19);
+
+        i = 10;
+        j = 0;
+        assert_se(VA_MACRO_VARINIT(MACRO_USE_TWICE_1L2_OR_B0, VA_GROUP(i - 10, j)) == 1);
+        assert_se(i == 10);
+        assert_se(j == 0);
+
+        assert_se(VA_MACRO_VARINIT(MACRO_USE_TWICE_1L2_OR_B0, VA_GROUP(i, j--)) == 0);
+        assert_se(i == 10);
+        assert_se(j == -1);
+}
+
+TEST(va_macro_varconst) {
+        _unused_ int i = 1, j = 0, k = 4444;
+
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS1_EVAL1, 1) == 1);
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS2_EVAL2, VA_GROUP(1, 10)) == 10);
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS6_EVAL4, VA_GROUP(0,i,1,k,3,4)) == 4444);
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS6_EVAL1, VA_GROUP(i,2,2,3,4,k)) == 1);
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS6_EVAL1, VA_GROUP(1000,2,3,4,k,0)) == 1000);
+        assert_se(VA_MACRO_VARCONST(MACRO_SUM12, VA_GROUP(1,10)) == 11);
+        assert_se(VA_MACRO_VARCONST(MACRO_SUM12, VA_GROUP(k,1)) == 4445);
+
+        i = 1234;
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS1_EVAL1, i) == 1234);
+        assert_se(VA_MACRO_VARCONST(MACRO_INT_USE_ARGS1_EVAL1, 1234) == i);
+}
+
+TEST(va_toomany) {
+        /* Test assumes largest __VA_EVAL_0x*() macro is 0x0200. */
+        assert_se(VA_NARGS(VA_NARGS_MAX_LESS_1) == 0x1ff);
+        assert_se(VA_NARGS(VA_NARGS_MAX_LESS_1,1) == 0x200);
+
+        assert_se(VA_WRAP(VA_WRAP_MACRO_LAST,
+                          VA_WRAP_SEPARATOR_NONE,
+                          -1,
+                          VA_WRAP_ZERO_NONE,
+                          VA_WRAP_TOOMANY_CONTEXT,
+                          VA_NARGS_MAX_LESS_1, -2) == -2);
+        assert_se(VA_WRAP(VA_WRAP_MACRO_LAST,
+                          VA_WRAP_SEPARATOR_NONE,
+                          -1,
+                          VA_WRAP_ZERO_NONE,
+                          VA_WRAP_TOOMANY_CONTEXT,
+                          VA_NARGS_MAX_LESS_1, -2, -3) == -1);
+}
+
+TEST(va_number) {
+        assert_se(___VANUM4(4,3,2,1) == 0x4321);
+        assert_se(___VANUM4(f,f,f,f) == 0xffff);
+        assert_se(___VANUM4(0,0,0,0) == 0);
+        assert_se(___VANUM4(0,0,0,1) == 1);
+        assert_se(___VANUM4(0,1,0,0) == 0x100);
+        assert_se(___VANUM4(1,0,0,1) == 0x1001);
+        assert_se(__VANUM4((1,0,0,1)) == 0x1001);
+}
+
+TEST(va_inc) {
+        assert_se(__VANUM4(__VAINC4((1,2,3,4))) == 0x1235);
+        assert_se(__VANUM4(__VAINC4((0,0,0,0))) == 1);
+        assert_se(__VANUM4(__VAINC4((0,0,0,1))) == 2);
+        assert_se(__VANUM4(__VAINC4((1,0,0,0))) == 0x1001);
+        assert_se(__VANUM4(__VAINC4((f,f,f,e))) == 0xffff);
+        assert_se(__VANUM4(__VAINC4((e,f,f,e))) == 0xefff);
+        assert_se(__VANUM4(__VAINC4((e,f,e,f))) == 0xeff0);
+        assert_se(__VANUM4(__VAINC4((d,f,f,f))) == 0xe000);
+}
+
+DEFINE_TEST_MAIN(LOG_INFO);

test/units/TEST-07-PID1.private-pids.sh

@@ -132,10 +132,12 @@ testcase_unpriv() {
         return 0
     fi
 
-    # The kernel has a restriction for unprivileged user namespaces where they cannot mount a less restrictive
+    # IMPORTANT: For /proc/ to be remounted in pid namespace within an unprivileged user namespace, there needs to
-    # instance of /proc/. So if /proc/ is masked (e.g. /proc/kmsg is over-mounted with tmpfs as systemd-nspawn does),
+    # be at least 1 unmasked procfs mount in ANY directory. Otherwise, if /proc/ is masked (e.g. /proc/scsi is
-    # then mounting a new /proc/ will fail and we will still see the host's /proc/. Thus, to allow tests to run in
+    # over-mounted with tmpfs), then mounting a new /proc/ will fail.
-    # a VM or nspawn, we mount a new proc on a temporary directory with no masking to bypass this kernel restriction.
+    #
+    # Thus, to guarantee PrivatePIDs=yes tests for unprivileged users pass, we mount a new procfs on a temporary
+    # directory with no masking. This will guarantee an unprivileged user can mount a new /proc/ successfully.
     mkdir -p /tmp/TEST-07-PID1-private-pids-proc
     mount -t proc proc /tmp/TEST-07-PID1-private-pids-proc
 
@@ -146,7 +148,16 @@ testcase_unpriv() {
     umount /tmp/TEST-07-PID1-private-pids-proc
     rm -rf /tmp/TEST-07-PID1-private-pids-proc
 
-    # Now verify the behavior with masking - units should fail as PrivatePIDs=yes has no graceful fallback.
+    # Now we will mask /proc/ by mounting tmpfs over /proc/scsi. This will guarantee that mounting /proc/ will fail
+    # for unprivileged users when using PrivatePIDs=yes. Now units should fail as PrivatePIDs=yes has no graceful
+    # fallback.
+    #
+    # Note some kernels do not have /proc/scsi so we verify the directory exists prior to running the test.
+    if [ ! -d /proc/scsi ]; then
+        echo "/proc/scsi does not exist, skipping unprivileged PrivatePIDs=yes test with masked /proc/"
+        return 0
+    fi
+
     if [[ "$HAS_EXISTING_SCSI_MOUNT" == "no" ]]; then
         mount -t tmpfs tmpfs /proc/scsi
     fi