userspace: Add `test` utility

This commit is contained in:
Bananymous 2025-06-08 23:56:39 +03:00
parent 6f74f3c386
commit 30d5d85d1d
2 changed files with 261 additions and 0 deletions

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@ -0,0 +1,14 @@
set(SOURCES
main.cpp
)
add_executable(test ${SOURCES})
banan_link_library(test ban)
install(TARGETS test OPTIONAL)
install(CODE "
if (EXISTS ${CMAKE_INSTALL_BINDIR}/test)
file(COPY_FILE ${CMAKE_INSTALL_BINDIR}/test ${CMAKE_INSTALL_BINDIR}/[ ONLY_IF_DIFFERENT)
endif()
")

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#include <BAN/Optional.h>
#include <BAN/Span.h>
#include <BAN/StringView.h>
#include <libgen.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
const char* argv0 = nullptr;
[[noreturn]] void exit_on_error(const char* format, ...)
{
fprintf(stderr, "%s: ", argv0);
va_list args;
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
exit(2);
__builtin_unreachable();
}
long long parse_integer(const char* string)
{
errno = 0;
char* endptr;
long long value = strtoll(string, &endptr, 0);
if (*endptr == '\0' && errno == 0)
return value;
exit_on_error("integer expression expected, got %s\n", string);
}
bool check_file_mode(const char* pathname, mode_t mask, mode_t mode)
{
const auto func = (mode == S_IFLNK) ? lstat : stat;
struct stat st;
if (func(pathname, &st) == -1)
return false;
return (st.st_mode & mask) == mode;
}
bool check_file_not_empty(const char* pathname)
{
struct stat st;
if (stat(pathname, &st) == -1)
return false;
return st.st_size > 0;
}
BAN::Optional<bool> evaluate_file_op(BAN::Span<const char*>& args)
{
struct FileOp
{
char name;
bool (*func)(const char*);
};
constexpr FileOp file_ops[] {
{ 'b', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFBLK); } },
{ 'c', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFCHR); } },
{ 'd', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFDIR); } },
{ 'e', [](auto* s) { return check_file_mode(s, 0, 0 ); } },
{ 'f', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFREG); } },
{ 'g', [](auto* s) { return check_file_mode(s, S_ISGID, S_ISGID); } },
{ 'h', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFLNK); } },
{ 'L', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFLNK); } },
{ 'p', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFIFO); } },
{ 'S', [](auto* s) { return check_file_mode(s, S_IFMT, S_IFSOCK); } },
{ 'u', [](auto* s) { return check_file_mode(s, S_ISUID, S_ISUID); } },
{ 's', [](auto* s) { return check_file_not_empty(s); } },
{ 'r', [](auto* s) { return access(s, R_OK) == 0; } },
{ 'w', [](auto* s) { return access(s, W_OK) == 0; } },
{ 'x', [](auto* s) { return access(s, X_OK) == 0; } },
};
if (args.size() < 2)
return {};
if (args[0][0] != '-' || args[0][1] == '\0' || args[0][2] != '\0')
return {};
for (const auto& file_op : file_ops)
{
if (args[0][1] != file_op.name)
continue;
const char* pathname = args[1];
args = args.slice(2);
return file_op.func(pathname);
}
return {};
}
BAN::Optional<bool> evaluate_string_op(BAN::Span<const char*>& args)
{
if (args.size() < 3)
return {};
if (args[1] != "="_sv && args[1] != "!="_sv)
return {};
const bool result = (args[1] == "="_sv) == (strcmp(args[0], args[2]) == 0);
args = args.slice(3);
return result;
}
BAN::Optional<bool> evaluate_numeric_op(BAN::Span<const char*>& args)
{
if (args.size() < 3)
return {};
struct NumericOp
{
BAN::StringView name;
bool (*func)(long long, long long);
};
constexpr NumericOp numeric_ops[] {
{ "-eq", [](auto val1, auto val2) { return val1 == val2; } },
{ "-ne", [](auto val1, auto val2) { return val1 != val2; } },
{ "-gt", [](auto val1, auto val2) { return val1 > val2; } },
{ "-ge", [](auto val1, auto val2) { return val1 >= val2; } },
{ "-lt", [](auto val1, auto val2) { return val1 < val2; } },
{ "-le", [](auto val1, auto val2) { return val1 <= val2; } },
};
for (const auto& numeric_op : numeric_ops)
{
if (args[1] != numeric_op.name)
continue;
auto val1 = parse_integer(args[0]);
auto val2 = parse_integer(args[2]);
args = args.slice(3);
return numeric_op.func(val1, val2);
}
return {};
}
bool evaluate(BAN::Span<const char*>& args);
bool evaluate_expression(BAN::Span<const char*>& args)
{
if (args.empty())
return false;
if (args.size() == 1 || args[1] == "-o"_sv || args[1] == "-a"_sv)
{
const bool result = (args[0] != ""_sv);
args = args.slice(1);
return result;
}
// the string comparison binary primaries '=' and "!=" shall have a higher
// precedence than any unary primary
if (auto result = evaluate_string_op(args); result.has_value())
return false;
if (args[0] == "!"_sv)
{
args = args.slice(1);
return !evaluate_expression(args);
}
if (args[0] == "-z"_sv || args[0] == "-n"_sv)
{
const bool want_empty = (args[0] == "-z"_sv);
const bool is_empty = (args[1] == ""_sv);
args = args.slice(2);
return want_empty == is_empty;
}
if (args[0] == "-t"_sv)
{
auto value = parse_integer(args[1]);
args = args.slice(2);
if (value < 0 || value > INT_MAX)
return false;
return isatty(value);
}
if (auto result = evaluate_file_op(args); result.has_value())
return result.value();
if (auto result = evaluate_numeric_op(args); result.has_value())
return result.value();
if (args[0] == "("_sv)
{
args = args.slice(1);
const bool value = evaluate(args);
if (args.empty() || args[0] != ")"_sv)
exit_on_error("missing ')'\n");
args = args.slice(1);
return value;
}
const bool result = args[0] != ""_sv;
args = args.slice(1);
return result;
}
bool evaluate(BAN::Span<const char*>& args)
{
bool value = evaluate_expression(args);
while (!args.empty())
{
// NOTE: POSIX says -a has higher precedence than -o, but other
// implementations just do it as left associative.
// Even linux man page says: 'Binary -a and -o are ambiguous.'
if (args[0] != "-o"_sv && args[0] != "-a"_sv)
break;
const bool op_and = (args[0] == "-a"_sv);
args = args.slice(1);
const bool rhs = evaluate_expression(args);
value = op_and ? (value && rhs) : (value || rhs);
}
return value;
}
int main(int argc, const char** argv)
{
argv0 = argv[0];
char argv0_copy[PATH_MAX];
strcpy(argv0_copy, argv0);
if (strcmp(basename(argv0_copy), "[") == 0)
{
if (strcmp(argv[argc - 1], "]") != 0)
exit_on_error("missing ']'\n");
argc--;
}
auto args = BAN::Span(argv + 1, argc - 1);
const bool result = evaluate(args);
if (!args.empty())
exit_on_error("parse error near '%s'\n", args[0]);
return result ? 0 : 1;
}