1 /* 2 * GLIB Compatibility Functions 3 * 4 * Copyright IBM, Corp. 2013 5 * 6 * Authors: 7 * Anthony Liguori <aliguori@us.ibm.com> 8 * Michael Tokarev <mjt@tls.msk.ru> 9 * Paolo Bonzini <pbonzini@redhat.com> 10 * 11 * This work is licensed under the terms of the GNU GPL, version 2 or later. 12 * See the COPYING file in the top-level directory. 13 * 14 */ 15 16 #ifndef QEMU_GLIB_COMPAT_H 17 #define QEMU_GLIB_COMPAT_H 18 19 /* Ask for warnings for anything that was marked deprecated in 20 * the defined version, or before. It is a candidate for rewrite. 21 */ 22 #define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_56 23 24 /* Ask for warnings if code tries to use function that did not 25 * exist in the defined version. These risk breaking builds 26 */ 27 #define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_56 28 29 #pragma GCC diagnostic push 30 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" 31 32 #include <glib.h> 33 #if defined(G_OS_UNIX) 34 #include <glib-unix.h> 35 #include <sys/types.h> 36 #include <pwd.h> 37 #endif 38 39 /* 40 * Note that because of the GLIB_VERSION_MAX_ALLOWED constant above, allowing 41 * use of functions from newer GLib via this compat header needs a little 42 * trickery to prevent warnings being emitted. 43 * 44 * Consider a function from newer glib-X.Y that we want to use 45 * 46 * int g_foo(const char *wibble) 47 * 48 * We must define a static inline function with the same signature that does 49 * what we need, but with a "_compat" suffix e.g. 50 * 51 * static inline void g_foo_compat(const char *wibble) 52 * { 53 * #if GLIB_CHECK_VERSION(X, Y, 0) 54 * g_foo(wibble) 55 * #else 56 * g_something_equivalent_in_older_glib(wibble); 57 * #endif 58 * } 59 * 60 * The #pragma at the top of this file turns off -Wdeprecated-declarations, 61 * ensuring this wrapper function impl doesn't trigger the compiler warning 62 * about using too new glib APIs. Finally we can do 63 * 64 * #define g_foo(a) g_foo_compat(a) 65 * 66 * So now the code elsewhere in QEMU, which *does* have the 67 * -Wdeprecated-declarations warning active, can call g_foo(...) as normal, 68 * without generating warnings. 69 */ 70 71 /* 72 * g_memdup2_qemu: 73 * @mem: (nullable): the memory to copy. 74 * @byte_size: the number of bytes to copy. 75 * 76 * Allocates @byte_size bytes of memory, and copies @byte_size bytes into it 77 * from @mem. If @mem is %NULL it returns %NULL. 78 * 79 * This replaces g_memdup(), which was prone to integer overflows when 80 * converting the argument from a #gsize to a #guint. 81 * 82 * This static inline version is a backport of the new public API from 83 * GLib 2.68, kept internal to GLib for backport to older stable releases. 84 * See https://gitlab.gnome.org/GNOME/glib/-/issues/2319. 85 * 86 * Returns: (nullable): a pointer to the newly-allocated copy of the memory, 87 * or %NULL if @mem is %NULL. 88 */ 89 static inline gpointer g_memdup2_qemu(gconstpointer mem, gsize byte_size) 90 { 91 #if GLIB_CHECK_VERSION(2, 68, 0) 92 return g_memdup2(mem, byte_size); 93 #else 94 gpointer new_mem; 95 96 if (mem && byte_size != 0) { 97 new_mem = g_malloc(byte_size); 98 memcpy(new_mem, mem, byte_size); 99 } else { 100 new_mem = NULL; 101 } 102 103 return new_mem; 104 #endif 105 } 106 #define g_memdup2(m, s) g_memdup2_qemu(m, s) 107 108 #if defined(G_OS_UNIX) 109 /* 110 * Note: The fallback implementation is not MT-safe, and it returns a copy of 111 * the libc passwd (must be g_free() after use) but not the content. Because of 112 * these important differences the caller must be aware of, it's not #define for 113 * GLib API substitution. 114 */ 115 static inline struct passwd * 116 g_unix_get_passwd_entry_qemu(const gchar *user_name, GError **error) 117 { 118 #if GLIB_CHECK_VERSION(2, 64, 0) 119 return g_unix_get_passwd_entry(user_name, error); 120 #else 121 struct passwd *p = getpwnam(user_name); 122 if (!p) { 123 g_set_error_literal(error, G_UNIX_ERROR, 0, g_strerror(errno)); 124 return NULL; 125 } 126 return (struct passwd *)g_memdup(p, sizeof(*p)); 127 #endif 128 } 129 #endif /* G_OS_UNIX */ 130 131 static inline bool 132 qemu_g_test_slow(void) 133 { 134 static int cached = -1; 135 if (cached == -1) { 136 cached = g_test_slow() || getenv("G_TEST_SLOW") != NULL; 137 } 138 return cached; 139 } 140 141 #undef g_test_slow 142 #undef g_test_thorough 143 #undef g_test_quick 144 #define g_test_slow() qemu_g_test_slow() 145 #define g_test_thorough() qemu_g_test_slow() 146 #define g_test_quick() (!qemu_g_test_slow()) 147 148 #pragma GCC diagnostic pop 149 150 #ifndef G_NORETURN 151 #define G_NORETURN G_GNUC_NORETURN 152 #endif 153 154 #endif 155