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_48 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_48 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 "_qemu" suffix e.g. 50 * 51 * static inline void g_foo_qemu(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_qemu(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 #if defined(_WIN32) && !GLIB_CHECK_VERSION(2, 50, 0) 72 /* 73 * g_poll has a problem on Windows when using 74 * timeouts < 10ms, so use wrapper. 75 */ 76 #define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout) 77 gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout); 78 #endif 79 80 #if defined(G_OS_UNIX) 81 /* 82 * Note: The fallback implementation is not MT-safe, and it returns a copy of 83 * the libc passwd (must be g_free() after use) but not the content. Because of 84 * these important differences the caller must be aware of, it's not #define for 85 * GLib API substitution. 86 */ 87 static inline struct passwd * 88 g_unix_get_passwd_entry_qemu(const gchar *user_name, GError **error) 89 { 90 #if GLIB_CHECK_VERSION(2, 64, 0) 91 return g_unix_get_passwd_entry(user_name, error); 92 #else 93 struct passwd *p = getpwnam(user_name); 94 if (!p) { 95 g_set_error_literal(error, G_UNIX_ERROR, 0, g_strerror(errno)); 96 return NULL; 97 } 98 return (struct passwd *)g_memdup(p, sizeof(*p)); 99 #endif 100 } 101 #endif /* G_OS_UNIX */ 102 103 #pragma GCC diagnostic pop 104 105 #endif 106