Merge pull request #20676 from gogsbread/sysctl-minimize-sideeffect

sysctl: minimize side effects when running `systemd-sysctl`

meson.build

@@ -707,8 +707,30 @@ else
         conf.set('DEFAULT_HIERARCHY', 'CGROUP_UNIFIED_ALL')
 endif
 
+extra_net_naming_schemes = []
+extra_net_naming_map = []
+foreach scheme: get_option('extra-net-naming-schemes').split(',')
+        if scheme != ''
+                name = scheme.split('=')[0]
+                value = scheme.split('=')[1]
+                NAME = name.underscorify().to_upper()
+                VALUE = []
+                foreach field: value.split('+')
+                        VALUE += 'NAMING_' + field.underscorify().to_upper()
+                endforeach
+                extra_net_naming_schemes += 'NAMING_@0@ = @1@,'.format(NAME, '|'.join(VALUE))
+                extra_net_naming_map += '{ "@0@", NAMING_@1@ },'.format(name, NAME)
+        endif
+endforeach
+conf.set('EXTRA_NET_NAMING_SCHEMES', ' '.join(extra_net_naming_schemes))
+conf.set('EXTRA_NET_NAMING_MAP', ' '.join(extra_net_naming_map))
+
 default_net_naming_scheme = get_option('default-net-naming-scheme')
 conf.set_quoted('DEFAULT_NET_NAMING_SCHEME', default_net_naming_scheme)
+if default_net_naming_scheme != 'latest'
+        conf.set('_DEFAULT_NET_NAMING_SCHEME_TEST',
+                 'NAMING_' + default_net_naming_scheme.underscorify().to_upper())
+endif
 
 time_epoch = get_option('time-epoch')
 if time_epoch == -1

meson_options.txt

@@ -200,8 +200,9 @@ option('fallback-hostname', type : 'string', value : 'localhost',
 option('default-hierarchy', type : 'combo',
        choices : ['legacy', 'hybrid', 'unified'], value : 'unified',
        description : 'default cgroup hierarchy')
-option('default-net-naming-scheme', type : 'combo',
+option('extra-net-naming-schemes', type : 'string',
-       choices : ['latest', 'v238', 'v239', 'v240', 'v241', 'v243', 'v245', 'v247', 'v249'],
+       description : 'comma-separated list of extra net.naming-scheme= definitions')
+option('default-net-naming-scheme', type : 'string', value : 'latest',
        description : 'default net.naming-scheme= value')
 option('status-unit-format-default', type : 'combo',
        choices : ['description', 'name', 'combined'],

src/basic/fileio.c

@@ -148,6 +148,30 @@ int write_string_stream_ts(
                         return -EBADF;
         }
 
+        if (flags & WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL) {
+                _cleanup_free_ char *t = NULL;
+
+                /* If value to be written is same as that of the existing value, then suppress the write. */
+
+                if (fd < 0) {
+                        fd = fileno(f);
+                        if (fd < 0)
+                                return -EBADF;
+                }
+
+                /* Read an additional byte to detect cases where the prefix matches but the rest
+                 * doesn't. Also, 0 returned by read_virtual_file_fd() means the read was truncated and
+                 * it won't be equal to the new value. */
+                if (read_virtual_file_fd(fd, strlen(line)+1, &t, NULL) > 0 &&
+                    streq_skip_trailing_chars(line, t, NEWLINE)) {
+                        log_debug("No change in value '%s', supressing write", line);
+                        return 0;
+                }
+
+                if (lseek(fd, 0, SEEK_SET) < 0)
+                        return -errno;
+        }
+
         needs_nl = !(flags & WRITE_STRING_FILE_AVOID_NEWLINE) && !endswith(line, "\n");
 
         if (needs_nl && (flags & WRITE_STRING_FILE_DISABLE_BUFFER)) {
@@ -263,10 +287,11 @@ int write_string_file_ts(
                 assert(!ts);
 
         /* We manually build our own version of fopen(..., "we") that works without O_CREAT and with O_NOFOLLOW if needed. */
-        fd = open(fn, O_WRONLY|O_CLOEXEC|O_NOCTTY |
+        fd = open(fn, O_CLOEXEC|O_NOCTTY |
                   (FLAGS_SET(flags, WRITE_STRING_FILE_NOFOLLOW) ? O_NOFOLLOW : 0) |
                   (FLAGS_SET(flags, WRITE_STRING_FILE_CREATE) ? O_CREAT : 0) |
-                  (FLAGS_SET(flags, WRITE_STRING_FILE_TRUNCATE) ? O_TRUNC : 0),
+                  (FLAGS_SET(flags, WRITE_STRING_FILE_TRUNCATE) ? O_TRUNC : 0) |
+                  (FLAGS_SET(flags, WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL) ? O_RDWR : O_WRONLY),
                   (FLAGS_SET(flags, WRITE_STRING_FILE_MODE_0600) ? 0600 : 0666));
         if (fd < 0) {
                 r = -errno;
@@ -375,9 +400,8 @@ int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
         return 1;
 }
 
-int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
+int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size) {
         _cleanup_free_ char *buf = NULL;
-        _cleanup_close_ int fd = -1;
         size_t n, size;
         int n_retries;
         bool truncated = false;
@@ -395,10 +419,7 @@ int read_virtual_file(const char *filename, size_t max_size, char **ret_contents
          * contents* may be returned. (Though the read is still done using one syscall.) Returns 0 on
          * partial success, 1 if untruncated contents were read. */
 
-        fd = open(filename, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+        assert(fd >= 0);
-        if (fd < 0)
-                return -errno;
-
         assert(max_size <= READ_VIRTUAL_BYTES_MAX || max_size == SIZE_MAX);
 
         /* Limit the number of attempts to read the number of bytes returned by fstat(). */
@@ -434,8 +455,8 @@ int read_virtual_file(const char *filename, size_t max_size, char **ret_contents
 
                         n_retries--;
                 } else if (n_retries > 1) {
-                        /* Files in /proc are generally smaller than the page size so let's start with a page size
+                        /* Files in /proc are generally smaller than the page size so let's start with
-                         * buffer from malloc and only use the max buffer on the final try. */
+                         * a page size buffer from malloc and only use the max buffer on the final try. */
                         size = MIN3(page_size() - 1, READ_VIRTUAL_BYTES_MAX, max_size);
                         n_retries = 1;
                 } else {
@@ -524,6 +545,18 @@ int read_virtual_file(const char *filename, size_t max_size, char **ret_contents
         return !truncated;
 }
 
+int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size) {
+        _cleanup_close_ int fd = -1;
+
+        assert(filename);
+
+        fd = open(filename, O_RDONLY | O_NOCTTY | O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        return read_virtual_file_fd(fd, max_size, ret_contents, ret_size);
+}
+
 int read_full_stream_full(
                 FILE *f,
                 const char *filename,

src/basic/fileio.h

@@ -26,6 +26,7 @@ typedef enum {
         WRITE_STRING_FILE_NOFOLLOW                   = 1 << 8,
         WRITE_STRING_FILE_MKDIR_0755                 = 1 << 9,
         WRITE_STRING_FILE_MODE_0600                  = 1 << 10,
+        WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL = 1 << 11,
 
         /* And before you wonder, why write_string_file_atomic_label_ts() is a separate function instead of just one
            more flag here: it's about linking: we don't want to pull -lselinux into all users of write_string_file()
@@ -67,6 +68,7 @@ static inline int read_full_file(const char *filename, char **ret_contents, size
         return read_full_file_full(AT_FDCWD, filename, UINT64_MAX, SIZE_MAX, 0, NULL, ret_contents, ret_size);
 }
 
+int read_virtual_file_fd(int fd, size_t max_size, char **ret_contents, size_t *ret_size);
 int read_virtual_file(const char *filename, size_t max_size, char **ret_contents, size_t *ret_size);
 static inline int read_full_virtual_file(const char *filename, char **ret_contents, size_t *ret_size) {
         return read_virtual_file(filename, SIZE_MAX, ret_contents, ret_size);

src/basic/format-util.c

@@ -3,23 +3,43 @@
 #include "format-util.h"
 #include "memory-util.h"
 #include "stdio-util.h"
+#include "strxcpyx.h"
+
+assert_cc(STRLEN("%") + DECIMAL_STR_MAX(int) <= IF_NAMESIZE);
+int format_ifname_full(int ifindex, FormatIfnameFlag flag, char buf[static IF_NAMESIZE]) {
+        if (ifindex <= 0)
+                return -EINVAL;
 
-assert_cc(DECIMAL_STR_MAX(int) + 1 <= IF_NAMESIZE + 1);
-char *format_ifname_full(int ifindex, char buf[static IF_NAMESIZE + 1], FormatIfnameFlag flag) {
-        /* Buffer is always cleared */
-        memzero(buf, IF_NAMESIZE + 1);
         if (if_indextoname(ifindex, buf))
-                return buf;
+                return 0;
 
         if (!FLAGS_SET(flag, FORMAT_IFNAME_IFINDEX))
-                return NULL;
+                return -errno;
 
         if (FLAGS_SET(flag, FORMAT_IFNAME_IFINDEX_WITH_PERCENT))
-                assert(snprintf_ok(buf, IF_NAMESIZE + 1, "%%%d", ifindex));
+                assert(snprintf_ok(buf, IF_NAMESIZE, "%%%d", ifindex));
         else
-                assert(snprintf_ok(buf, IF_NAMESIZE + 1, "%d", ifindex));
+                assert(snprintf_ok(buf, IF_NAMESIZE, "%d", ifindex));
 
-        return buf;
+        return 0;
+}
+
+int format_ifname_full_alloc(int ifindex, FormatIfnameFlag flag, char **ret) {
+        char buf[IF_NAMESIZE], *copy;
+        int r;
+
+        assert(ret);
+
+        r = format_ifname_full(ifindex, flag, buf);
+        if (r < 0)
+                return r;
+
+        copy = strdup(buf);
+        if (!copy)
+                return -ENOMEM;
+
+        *ret = copy;
+        return 0;
 }
 
 char *format_bytes_full(char *buf, size_t l, uint64_t t, FormatBytesFlag flag) {

src/basic/format-util.h

@@ -61,10 +61,23 @@ typedef enum {
         FORMAT_IFNAME_IFINDEX_WITH_PERCENT = (1 << 1) | FORMAT_IFNAME_IFINDEX,
 } FormatIfnameFlag;
 
-char *format_ifname_full(int ifindex, char buf[static IF_NAMESIZE + 1], FormatIfnameFlag flag);
+int format_ifname_full(int ifindex, FormatIfnameFlag flag, char buf[static IF_NAMESIZE]);
-static inline char *format_ifname(int ifindex, char buf[static IF_NAMESIZE + 1]) {
+int format_ifname_full_alloc(int ifindex, FormatIfnameFlag flag, char **ret);
-        return format_ifname_full(ifindex, buf, 0);
+
+static inline int format_ifname(int ifindex, char buf[static IF_NAMESIZE]) {
+        return format_ifname_full(ifindex, 0, buf);
 }
+static inline int format_ifname_alloc(int ifindex, char **ret) {
+        return format_ifname_full_alloc(ifindex, 0, ret);
+}
+
+static inline char *_format_ifname_full(int ifindex, FormatIfnameFlag flag, char buf[static IF_NAMESIZE]) {
+        (void) format_ifname_full(ifindex, flag, buf);
+        return buf;
+}
+
+#define FORMAT_IFNAME_FULL(index, flag) _format_ifname_full(index, flag, (char[IF_NAMESIZE]){})
+#define FORMAT_IFNAME(index) _format_ifname_full(index, 0, (char[IF_NAMESIZE]){})
 
 typedef enum {
         FORMAT_BYTES_USE_IEC     = 1 << 0,

src/basic/socket-util.c

@@ -455,23 +455,23 @@ int sockaddr_pretty(
                         if (r < 0)
                                 return -ENOMEM;
                 } else {
-                        char a[INET6_ADDRSTRLEN], ifname[IF_NAMESIZE + 1];
+                        char a[INET6_ADDRSTRLEN];
 
                         inet_ntop(AF_INET6, &sa->in6.sin6_addr, a, sizeof(a));
-                        if (sa->in6.sin6_scope_id != 0)
-                                format_ifname_full(sa->in6.sin6_scope_id, ifname, FORMAT_IFNAME_IFINDEX);
 
                         if (include_port) {
-                                r = asprintf(&p,
+                                if (asprintf(&p,
                                              "[%s]:%u%s%s",
                                              a,
                                              be16toh(sa->in6.sin6_port),
                                              sa->in6.sin6_scope_id != 0 ? "%" : "",
-                                             sa->in6.sin6_scope_id != 0 ? ifname : "");
+                                             FORMAT_IFNAME_FULL(sa->in6.sin6_scope_id, FORMAT_IFNAME_IFINDEX)) < 0)
-                                if (r < 0)
                                         return -ENOMEM;
                         } else {
-                                p = sa->in6.sin6_scope_id != 0 ? strjoin(a, "%", ifname) : strdup(a);
+                                if (sa->in6.sin6_scope_id != 0)
+                                        p = strjoin(a, "%", FORMAT_IFNAME_FULL(sa->in6.sin6_scope_id, FORMAT_IFNAME_IFINDEX));
+                                else
+                                        p = strdup(a);
                                 if (!p)
                                         return -ENOMEM;
                         }
@@ -1233,7 +1233,7 @@ int socket_bind_to_ifname(int fd, const char *ifname) {
 }
 
 int socket_bind_to_ifindex(int fd, int ifindex) {
-        char ifname[IF_NAMESIZE + 1];
+        char ifname[IF_NAMESIZE];
         int r;
 
         assert(fd >= 0);
@@ -1251,8 +1251,9 @@ int socket_bind_to_ifindex(int fd, int ifindex) {
                 return r;
 
         /* Fall back to SO_BINDTODEVICE on kernels < 5.0 which didn't have SO_BINDTOIFINDEX */
-        if (!format_ifname(ifindex, ifname))
+        r = format_ifname(ifindex, ifname);
-                return -errno;
+        if (r < 0)
+                return r;
 
         return socket_bind_to_ifname(fd, ifname);
 }

src/basic/string-util.c

@@ -1146,3 +1146,19 @@ int string_contains_word_strv(const char *string, const char *separators, char *
                 *ret_word = found;
         return !!found;
 }
+
+bool streq_skip_trailing_chars(const char *s1, const char *s2, const char *ok) {
+        if (!s1 && !s2)
+                return true;
+        if (!s1 || !s2)
+                return false;
+
+        if (!ok)
+                ok = WHITESPACE;
+
+        for (; *s1 && *s2; s1++, s2++)
+                if (*s1 != *s2)
+                        break;
+
+        return in_charset(s1, ok) && in_charset(s2, ok);
+}

src/basic/string-util.h

@@ -226,3 +226,5 @@ int string_contains_word_strv(const char *string, const char *separators, char *
 static inline int string_contains_word(const char *string, const char *separators, const char *word) {
         return string_contains_word_strv(string, separators, STRV_MAKE(word), NULL);
 }
+
+bool streq_skip_trailing_chars(const char *s1, const char *s2, const char *ok);

src/basic/sysctl-util.c

@@ -58,7 +58,7 @@ int sysctl_write(const char *property, const char *value) {
 
         log_debug("Setting '%s' to '%s'", p, value);
 
-        return write_string_file(p, value, WRITE_STRING_FILE_VERIFY_ON_FAILURE | WRITE_STRING_FILE_DISABLE_BUFFER);
+        return write_string_file(p, value, WRITE_STRING_FILE_VERIFY_ON_FAILURE | WRITE_STRING_FILE_DISABLE_BUFFER | WRITE_STRING_FILE_SUPPRESS_REDUNDANT_VIRTUAL);
 }
 
 int sysctl_writef(const char *property, const char *format, ...) {

src/core/scope.c

@@ -52,7 +52,7 @@ static void scope_done(Unit *u) {
         s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
 }
 
-static int scope_running_timeout(Scope *s) {
+static usec_t scope_running_timeout(Scope *s) {
         usec_t delta = 0;
 
         assert(s);

src/core/service.c

@@ -515,7 +515,7 @@ static void service_remove_fd_store(Service *s, const char *name) {
         }
 }
 
-static int service_running_timeout(Service *s) {
+static usec_t service_running_timeout(Service *s) {
         usec_t delta = 0;
 
         assert(s);

src/libsystemd-network/dhcp-internal.h

@@ -12,7 +12,7 @@
 #include "sd-dhcp-client.h"
 
 #include "dhcp-protocol.h"
-#include "log-link.h"
+#include "network-common.h"
 #include "socket-util.h"
 
 typedef struct sd_dhcp_option {
@@ -75,10 +75,10 @@ void dhcp_client_set_test_mode(sd_dhcp_client *client, bool test_mode);
 #define log_dhcp_client_errno(client, error, fmt, ...)          \
         log_interface_prefix_full_errno(                        \
                 "DHCPv4 client: ",                              \
-                sd_dhcp_client_get_ifname(client),              \
+                sd_dhcp_client, client,                         \
                 error, fmt, ##__VA_ARGS__)
 #define log_dhcp_client(client, fmt, ...)                       \
         log_interface_prefix_full_errno_zerook(                 \
                 "DHCPv4 client: ",                              \
-                sd_dhcp_client_get_ifname(client),              \
+                sd_dhcp_client, client,                         \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/dhcp-server-internal.h

@@ -9,8 +9,8 @@
 #include "sd-event.h"
 
 #include "dhcp-internal.h"
+#include "network-common.h"
 #include "ordered-set.h"
-#include "log-link.h"
 #include "time-util.h"
 
 typedef enum DHCPRawOption {
@@ -112,10 +112,10 @@ int client_id_compare_func(const DHCPClientId *a, const DHCPClientId *b);
 #define log_dhcp_server_errno(server, error, fmt, ...)          \
         log_interface_prefix_full_errno(                        \
                 "DHCPv4 server: ",                              \
-                sd_dhcp_server_get_ifname(server),              \
+                sd_dhcp_server, server,                         \
                 error, fmt, ##__VA_ARGS__)
 #define log_dhcp_server(server, fmt, ...)                       \
         log_interface_prefix_full_errno_zerook(                 \
                 "DHCPv4 server: ",                              \
-                sd_dhcp_server_get_ifname(server),              \
+                sd_dhcp_server, server,                         \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/dhcp6-internal.h

@@ -13,8 +13,8 @@
 
 #include "hashmap.h"
 #include "list.h"
-#include "log-link.h"
 #include "macro.h"
+#include "network-common.h"
 #include "sparse-endian.h"
 
 typedef struct sd_dhcp6_option {
@@ -125,10 +125,10 @@ void dhcp6_client_set_test_mode(sd_dhcp6_client *client, bool test_mode);
 #define log_dhcp6_client_errno(client, error, fmt, ...)         \
         log_interface_prefix_full_errno(                        \
                 "DHCPv6 client: ",                              \
-                sd_dhcp6_client_get_ifname(client),             \
+                sd_dhcp6_client, client,                        \
                 error, fmt, ##__VA_ARGS__)
 #define log_dhcp6_client(client, fmt, ...)                      \
         log_interface_prefix_full_errno_zerook(                 \
                 "DHCPv6 client: ",                              \
-                sd_dhcp6_client_get_ifname(client),             \
+                sd_dhcp6_client, client,                        \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/lldp-rx-internal.h

@@ -5,7 +5,7 @@
 #include "sd-lldp-rx.h"
 
 #include "hashmap.h"
-#include "log-link.h"
+#include "network-common.h"
 #include "prioq.h"
 
 struct sd_lldp_rx {
@@ -39,10 +39,10 @@ sd_lldp_rx_event_t lldp_rx_event_from_string(const char *s) _pure_;
 #define log_lldp_rx_errno(lldp_rx, error, fmt, ...)     \
         log_interface_prefix_full_errno(                \
                 "LLDP Rx: ",                            \
-                sd_lldp_rx_get_ifname(lldp_rx),         \
+                sd_lldp_rx, lldp_rx,                    \
                 error, fmt, ##__VA_ARGS__)
 #define log_lldp_rx(lldp_rx, fmt, ...)                  \
         log_interface_prefix_full_errno_zerook(         \
                 "LLDP Rx: ",                            \
-                sd_lldp_rx_get_ifname(lldp_rx),         \
+                sd_lldp_rx, lldp_rx,                    \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/ndisc-internal.h

@@ -7,7 +7,7 @@
 
 #include "sd-ndisc.h"
 
-#include "log-link.h"
+#include "network-common.h"
 #include "time-util.h"
 
 #define NDISC_ROUTER_SOLICITATION_INTERVAL (4U * USEC_PER_SEC)
@@ -44,10 +44,10 @@ sd_ndisc_event_t ndisc_event_from_string(const char *s) _pure_;
 #define log_ndisc_errno(ndisc, error, fmt, ...)         \
         log_interface_prefix_full_errno(                \
                 "NDISC: ",                              \
-                sd_ndisc_get_ifname(ndisc),             \
+                sd_ndisc, ndisc,                        \
                 error, fmt, ##__VA_ARGS__)
 #define log_ndisc(ndisc, fmt, ...)                      \
         log_interface_prefix_full_errno_zerook(         \
                 "NDISC: ",                              \
-                sd_ndisc_get_ifname(ndisc),             \
+                sd_ndisc, ndisc,                        \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/network-common.c

@@ -2,23 +2,14 @@
 
 #include "format-util.h"
 #include "network-common.h"
-#include "string-util.h"
-
-const char *get_ifname(int ifindex, char **ifname) {
-        char buf[IF_NAMESIZE + 1];
 
+int get_ifname(int ifindex, char **ifname) {
         assert(ifname);
 
         /* This sets ifname only when it is not set yet. */
 
         if (*ifname)
-                return *ifname;
+                return 0;
 
-        if (ifindex <= 0)
+        return format_ifname_alloc(ifindex, ifname);
-                return NULL;
-
-        if (!format_ifname(ifindex, buf))
-                return NULL;
-
-        return *ifname = strdup(buf);
 }

src/libsystemd-network/network-common.h

@@ -1,4 +1,28 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-const char *get_ifname(int ifindex, char **ifname);
+#include "log-link.h"
+
+#define log_interface_prefix_full_errno_zerook(prefix, type, val, error, fmt, ...) \
+        ({                                                              \
+                int _e = (error);                                       \
+                if (DEBUG_LOGGING) {                                    \
+                        const char *_n = NULL;                          \
+                                                                        \
+                        (void) type##_get_ifname(val, &_n);             \
+                        log_interface_full_errno_zerook(                \
+                                _n, LOG_DEBUG, _e, prefix fmt,          \
+                                ##__VA_ARGS__);                         \
+                }                                                       \
+                -ERRNO_VALUE(_e);                                       \
+        })
+
+#define log_interface_prefix_full_errno(prefix, type, val, error, fmt, ...) \
+        ({                                                              \
+                int _error = (error);                                   \
+                ASSERT_NON_ZERO(_error);                                \
+                log_interface_prefix_full_errno_zerook(                 \
+                        prefix, type, val, _error, fmt, ##__VA_ARGS__); \
+        })
+
+int get_ifname(int ifindex, char **ifname);

src/libsystemd-network/radv-internal.h

@@ -7,8 +7,8 @@
 
 #include "sd-radv.h"
 
-#include "log-link.h"
 #include "list.h"
+#include "network-common.h"
 #include "sparse-endian.h"
 
 assert_cc(SD_RADV_DEFAULT_MIN_TIMEOUT_USEC <= SD_RADV_DEFAULT_MAX_TIMEOUT_USEC);
@@ -128,10 +128,10 @@ struct sd_radv_route_prefix {
 #define log_radv_errno(radv, error, fmt, ...)           \
         log_interface_prefix_full_errno(                \
                 "RADV: ",                               \
-                sd_radv_get_ifname(radv),               \
+                sd_radv, radv,                          \
                 error, fmt, ##__VA_ARGS__)
 #define log_radv(radv, fmt, ...)                        \
         log_interface_prefix_full_errno_zerook(         \
                 "RADV: ",                               \
-                sd_radv_get_ifname(radv),               \
+                sd_radv, radv,                          \
                 0, fmt, ##__VA_ARGS__)

src/libsystemd-network/sd-dhcp-client.c

@@ -297,11 +297,19 @@ int sd_dhcp_client_set_ifname(sd_dhcp_client *client, const char *ifname) {
         return free_and_strdup(&client->ifname, ifname);
 }
 
-const char *sd_dhcp_client_get_ifname(sd_dhcp_client *client) {
+int sd_dhcp_client_get_ifname(sd_dhcp_client *client, const char **ret) {
-        if (!client)
+        int r;
-                return NULL;
 
-        return get_ifname(client->ifindex, &client->ifname);
+        assert_return(client, -EINVAL);
+
+        r = get_ifname(client->ifindex, &client->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = client->ifname;
+
+        return 0;
 }
 
 int sd_dhcp_client_set_mac(

src/libsystemd-network/sd-dhcp-server.c

@@ -230,11 +230,19 @@ int sd_dhcp_server_set_ifname(sd_dhcp_server *server, const char *ifname) {
         return free_and_strdup(&server->ifname, ifname);
 }
 
-const char *sd_dhcp_server_get_ifname(sd_dhcp_server *server) {
+int sd_dhcp_server_get_ifname(sd_dhcp_server *server, const char **ret) {
-        if (!server)
+        int r;
-                return NULL;
 
-        return get_ifname(server->ifindex, &server->ifname);
+        assert_return(server, -EINVAL);
+
+        r = get_ifname(server->ifindex, &server->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = server->ifname;
+
+        return 0;
 }
 
 int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int64_t priority) {

src/libsystemd-network/sd-dhcp6-client.c

@@ -179,11 +179,19 @@ int sd_dhcp6_client_set_ifname(sd_dhcp6_client *client, const char *ifname) {
         return free_and_strdup(&client->ifname, ifname);
 }
 
-const char *sd_dhcp6_client_get_ifname(sd_dhcp6_client *client) {
+int sd_dhcp6_client_get_ifname(sd_dhcp6_client *client, const char **ret) {
-        if (!client)
+        int r;
-                return NULL;
 
-        return get_ifname(client->ifindex, &client->ifname);
+        assert_return(client, -EINVAL);
+
+        r = get_ifname(client->ifindex, &client->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = client->ifname;
+
+        return 0;
 }
 
 int sd_dhcp6_client_set_local_address(

src/libsystemd-network/sd-ipv4acd.c

@@ -17,7 +17,6 @@
 #include "event-util.h"
 #include "fd-util.h"
 #include "in-addr-util.h"
-#include "log-link.h"
 #include "memory-util.h"
 #include "network-common.h"
 #include "random-util.h"
@@ -81,12 +80,12 @@ struct sd_ipv4acd {
 #define log_ipv4acd_errno(acd, error, fmt, ...)         \
         log_interface_prefix_full_errno(                \
                 "IPv4ACD: ",                            \
-                sd_ipv4acd_get_ifname(acd),             \
+                sd_ipv4acd, acd,                        \
                 error, fmt, ##__VA_ARGS__)
 #define log_ipv4acd(acd, fmt, ...)                      \
         log_interface_prefix_full_errno_zerook(         \
                 "IPv4ACD: ",                            \
-                sd_ipv4acd_get_ifname(acd),             \
+                sd_ipv4acd, acd,                        \
                 0, fmt, ##__VA_ARGS__)
 
 static const char * const ipv4acd_state_table[_IPV4ACD_STATE_MAX] = {
@@ -445,11 +444,19 @@ int sd_ipv4acd_set_ifname(sd_ipv4acd *acd, const char *ifname) {
         return free_and_strdup(&acd->ifname, ifname);
 }
 
-const char *sd_ipv4acd_get_ifname(sd_ipv4acd *acd) {
+int sd_ipv4acd_get_ifname(sd_ipv4acd *acd, const char **ret) {
-        if (!acd)
+        int r;
-                return NULL;
 
-        return get_ifname(acd->ifindex, &acd->ifname);
+        assert_return(acd, -EINVAL);
+
+        r = get_ifname(acd->ifindex, &acd->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = acd->ifname;
+
+        return 0;
 }
 
 int sd_ipv4acd_set_mac(sd_ipv4acd *acd, const struct ether_addr *addr) {

src/libsystemd-network/sd-ipv4ll.c

@@ -15,7 +15,7 @@
 #include "alloc-util.h"
 #include "ether-addr-util.h"
 #include "in-addr-util.h"
-#include "log-link.h"
+#include "network-common.h"
 #include "random-util.h"
 #include "siphash24.h"
 #include "sparse-endian.h"
@@ -55,12 +55,12 @@ struct sd_ipv4ll {
 #define log_ipv4ll_errno(ll, error, fmt, ...)           \
         log_interface_prefix_full_errno(                \
                 "IPv4LL: ",                             \
-                sd_ipv4ll_get_ifname(ll),               \
+                sd_ipv4ll, ll,                          \
                 error, fmt, ##__VA_ARGS__)
 #define log_ipv4ll(ll, fmt, ...)                        \
         log_interface_prefix_full_errno_zerook(         \
                 "IPv4LL: ",                             \
-                sd_ipv4ll_get_ifname(ll),               \
+                sd_ipv4ll, ll,                          \
                 0, fmt, ##__VA_ARGS__)
 
 static void ipv4ll_on_acd(sd_ipv4acd *acd, int event, void *userdata);
@@ -133,11 +133,10 @@ int sd_ipv4ll_set_ifname(sd_ipv4ll *ll, const char *ifname) {
         return sd_ipv4acd_set_ifname(ll->acd, ifname);
 }
 
-const char *sd_ipv4ll_get_ifname(sd_ipv4ll *ll) {
+int sd_ipv4ll_get_ifname(sd_ipv4ll *ll, const char **ret) {
-        if (!ll)
+        assert_return(ll, -EINVAL);
-                return NULL;
 
-        return sd_ipv4acd_get_ifname(ll->acd);
+        return sd_ipv4acd_get_ifname(ll->acd, ret);
 }
 
 int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {

src/libsystemd-network/sd-lldp-rx.c

@@ -359,11 +359,19 @@ int sd_lldp_rx_set_ifname(sd_lldp_rx *lldp_rx, const char *ifname) {
         return free_and_strdup(&lldp_rx->ifname, ifname);
 }
 
-const char *sd_lldp_rx_get_ifname(sd_lldp_rx *lldp_rx) {
+int sd_lldp_rx_get_ifname(sd_lldp_rx *lldp_rx, const char **ret) {
-        if (!lldp_rx)
+        int r;
-                return NULL;
 
-        return get_ifname(lldp_rx->ifindex, &lldp_rx->ifname);
+        assert_return(lldp_rx, -EINVAL);
+
+        r = get_ifname(lldp_rx->ifindex, &lldp_rx->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = lldp_rx->ifname;
+
+        return 0;
 }
 
 static sd_lldp_rx *lldp_rx_free(sd_lldp_rx *lldp_rx) {

src/libsystemd-network/sd-lldp-tx.c

@@ -12,7 +12,6 @@
 #include "ether-addr-util.h"
 #include "fd-util.h"
 #include "hostname-util.h"
-#include "log-link.h"
 #include "network-common.h"
 #include "random-util.h"
 #include "socket-util.h"
@@ -70,12 +69,12 @@ struct sd_lldp_tx {
 #define log_lldp_tx_errno(lldp_tx, error, fmt, ...)     \
         log_interface_prefix_full_errno(                \
                 "LLDP Tx: ",                            \
-                sd_lldp_tx_get_ifname(lldp_tx),         \
+                sd_lldp_tx, lldp_tx,                    \
                 error, fmt, ##__VA_ARGS__)
 #define log_lldp_tx(lldp_tx, fmt, ...)                  \
         log_interface_prefix_full_errno_zerook(         \
                 "LLDP Tx: ",                            \
-                sd_lldp_tx_get_ifname(lldp_tx),         \
+                sd_lldp_tx, lldp_tx,                    \
                 0, fmt, ##__VA_ARGS__)
 
 static sd_lldp_tx *lldp_tx_free(sd_lldp_tx *lldp_tx) {
@@ -131,11 +130,19 @@ int sd_lldp_tx_set_ifname(sd_lldp_tx *lldp_tx, const char *ifname) {
         return free_and_strdup(&lldp_tx->ifname, ifname);
 }
 
-const char *sd_lldp_tx_get_ifname(sd_lldp_tx *lldp_tx) {
+int sd_lldp_tx_get_ifname(sd_lldp_tx *lldp_tx, const char **ret) {
-        if (!lldp_tx)
+        int r;
-                return NULL;
 
-        return get_ifname(lldp_tx->ifindex, &lldp_tx->ifname);
+        assert_return(lldp_tx, -EINVAL);
+
+        r = get_ifname(lldp_tx->ifindex, &lldp_tx->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = lldp_tx->ifname;
+
+        return 0;
 }
 
 int sd_lldp_tx_set_multicast_mode(sd_lldp_tx *lldp_tx, sd_lldp_multicast_mode_t mode) {
@@ -222,7 +229,7 @@ static size_t lldp_tx_calculate_maximum_packet_size(sd_lldp_tx *lldp_tx, const c
                 /* Chassis ID */
                 2 + 1 + (SD_ID128_STRING_MAX - 1) +
                 /* Port ID */
-                2 + 1 + strlen_ptr(sd_lldp_tx_get_ifname(lldp_tx)) +
+                2 + 1 + strlen_ptr(lldp_tx->ifname) +
                 /* Port description */
                 2 + strlen_ptr(lldp_tx->port_description) +
                 /* System name */
@@ -334,6 +341,11 @@ static int lldp_tx_create_packet(sd_lldp_tx *lldp_tx, size_t *ret_packet_size, u
         assert(ret_packet_size);
         assert(ret_packet);
 
+        /* If ifname is not set yet, set ifname from ifindex. */
+        r = sd_lldp_tx_get_ifname(lldp_tx, NULL);
+        if (r < 0)
+                return r;
+
         r = sd_id128_get_machine(&machine_id);
         if (r < 0)
                 return r;
@@ -365,7 +377,7 @@ static int lldp_tx_create_packet(sd_lldp_tx *lldp_tx, size_t *ret_packet_size, u
 
         r = packet_append_prefixed_string(packet, packet_size, &offset, SD_LLDP_TYPE_PORT_ID,
                                           1, (const uint8_t[]) { SD_LLDP_PORT_SUBTYPE_INTERFACE_NAME },
-                                          sd_lldp_tx_get_ifname(lldp_tx));
+                                          lldp_tx->ifname);
         if (r < 0)
                 return r;
 

src/libsystemd-network/sd-ndisc.c

@@ -74,11 +74,19 @@ int sd_ndisc_set_ifname(sd_ndisc *nd, const char *ifname) {
         return free_and_strdup(&nd->ifname, ifname);
 }
 
-const char *sd_ndisc_get_ifname(sd_ndisc *nd) {
+int sd_ndisc_get_ifname(sd_ndisc *nd, const char **ret) {
-        if (!nd)
+        int r;
-                return NULL;
 
-        return get_ifname(nd->ifindex, &nd->ifname);
+        assert_return(nd, -EINVAL);
+
+        r = get_ifname(nd->ifindex, &nd->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = nd->ifname;
+
+        return 0;
 }
 
 _public_ int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) {

src/libsystemd-network/sd-radv.c

@@ -438,11 +438,19 @@ int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
         return free_and_strdup(&ra->ifname, ifname);
 }
 
-const char *sd_radv_get_ifname(sd_radv *ra) {
+int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
-        if (!ra)
+        int r;
-                return NULL;
 
-        return get_ifname(ra->ifindex, &ra->ifname);
+        assert_return(ra, -EINVAL);
+
+        r = get_ifname(ra->ifindex, &ra->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = ra->ifname;
+
+        return 0;
 }
 
 _public_ int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {

src/libsystemd/sd-device/sd-device.c

@@ -284,12 +284,12 @@ _public_ int sd_device_new_from_ifname(sd_device **ret, const char *ifname) {
 }
 
 _public_ int sd_device_new_from_ifindex(sd_device **ret, int ifindex) {
-        char ifname[IF_NAMESIZE + 1];
+        char ifname[IF_NAMESIZE];
 
         assert_return(ret, -EINVAL);
         assert_return(ifindex > 0, -EINVAL);
 
-        if (!format_ifname(ifindex, ifname))
+        if (format_ifname(ifindex, ifname) < 0)
                 return -ENODEV;
 
         return device_new_from_main_ifname(ret, ifname);

src/libsystemd/sd-netlink/netlink-util.c

@@ -12,7 +12,7 @@
 int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {
         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         _cleanup_strv_free_ char **alternative_names = NULL;
-        char old_name[IF_NAMESIZE + 1] = {};
+        char old_name[IF_NAMESIZE] = {};
         int r;
 
         assert(rtnl);
@@ -33,7 +33,9 @@ int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {
                         return log_debug_errno(r, "Failed to remove '%s' from alternative names on network interface %i: %m",
                                                name, ifindex);
 
-                format_ifname(ifindex, old_name);
+                r = format_ifname(ifindex, old_name);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to get current name of network interface %i: %m", ifindex);
         }
 
         r = sd_rtnl_message_new_link(*rtnl, &message, RTM_SETLINK, ifindex);

src/machine/machinectl.c

@@ -557,9 +557,9 @@ static void print_machine_status_info(sd_bus *bus, MachineStatusInfo *i) {
                 fputs("\t   Iface:", stdout);
 
                 for (size_t c = 0; c < i->n_netif; c++) {
-                        char name[IF_NAMESIZE+1];
+                        char name[IF_NAMESIZE];
 
-                        if (format_ifname(i->netif[c], name)) {
+                        if (format_ifname(i->netif[c], name) >= 0) {
                                 fputc(' ', stdout);
                                 fputs(name, stdout);
 

src/network/networkctl.c

@@ -1044,7 +1044,6 @@ static int dump_gateways(
 
         for (int i = 0; i < n; i++) {
                 _cleanup_free_ char *gateway = NULL, *description = NULL;
-                char name[IF_NAMESIZE+1];
 
                 r = in_addr_to_string(local[i].family, &local[i].address, &gateway);
                 if (r < 0)
@@ -1063,7 +1062,7 @@ static int dump_gateways(
                 r = strv_extendf(&buf, "%s%s%s",
                                  gateway,
                                  ifindex <= 0 ? " on " : "",
-                                 ifindex <= 0 ? format_ifname_full(local[i].ifindex, name, FORMAT_IFNAME_IFINDEX_WITH_PERCENT) : "");
+                                 ifindex <= 0 ? FORMAT_IFNAME_FULL(local[i].ifindex, FORMAT_IFNAME_IFINDEX_WITH_PERCENT) : "");
                 if (r < 0)
                         return log_oom();
         }
@@ -1094,7 +1093,6 @@ static int dump_addresses(
 
         for (int i = 0; i < n; i++) {
                 _cleanup_free_ char *pretty = NULL;
-                char name[IF_NAMESIZE+1];
 
                 r = in_addr_to_string(local[i].family, &local[i].address, &pretty);
                 if (r < 0)
@@ -1118,7 +1116,7 @@ static int dump_addresses(
                 r = strv_extendf(&buf, "%s%s%s",
                                  pretty,
                                  ifindex <= 0 ? " on " : "",
-                                 ifindex <= 0 ? format_ifname_full(local[i].ifindex, name, FORMAT_IFNAME_IFINDEX_WITH_PERCENT) : "");
+                                 ifindex <= 0 ? FORMAT_IFNAME_FULL(local[i].ifindex, FORMAT_IFNAME_IFINDEX_WITH_PERCENT) : "");
                 if (r < 0)
                         return log_oom();
         }
@@ -2682,12 +2680,9 @@ static int link_up_down(int argc, char *argv[], void *userdata) {
         SET_FOREACH(p, indexes) {
                 index = PTR_TO_INT(p);
                 r = link_up_down_send_message(rtnl, argv[0], index);
-                if (r < 0) {
+                if (r < 0)
-                        char ifname[IF_NAMESIZE + 1];
-
                         return log_error_errno(r, "Failed to bring %s interface %s: %m",
-                                               argv[0], format_ifname_full(index, ifname, FORMAT_IFNAME_IFINDEX));
+                                               argv[0], FORMAT_IFNAME_FULL(index, FORMAT_IFNAME_IFINDEX));
-                }
         }
 
         return r;
@@ -2720,12 +2715,9 @@ static int link_delete(int argc, char *argv[], void *userdata) {
         SET_FOREACH(p, indexes) {
                 index = PTR_TO_INT(p);
                 r = link_delete_send_message(rtnl, index);
-                if (r < 0) {
+                if (r < 0)
-                        char ifname[IF_NAMESIZE + 1];
-
                         return log_error_errno(r, "Failed to delete interface %s: %m",
-                                               format_ifname_full(index, ifname, FORMAT_IFNAME_IFINDEX));
+                                               FORMAT_IFNAME_FULL(index, FORMAT_IFNAME_IFINDEX));
-                }
         }
 
         return r;
@@ -2844,12 +2836,9 @@ static int verb_reconfigure(int argc, char *argv[], void *userdata) {
         SET_FOREACH(p, indexes) {
                 index = PTR_TO_INT(p);
                 r = bus_call_method(bus, bus_network_mgr, "ReconfigureLink", &error, NULL, "i", index);
-                if (r < 0) {
+                if (r < 0)
-                        char ifname[IF_NAMESIZE + 1];
-
                         return log_error_errno(r, "Failed to reconfigure network interface %s: %m",
-                                               format_ifname_full(index, ifname, FORMAT_IFNAME_IFINDEX));
+                                               FORMAT_IFNAME_FULL(index, FORMAT_IFNAME_IFINDEX));
-                }
         }
 
         return 0;

src/network/networkd-link.c

@@ -2212,7 +2212,7 @@ static int link_update_alternative_names(Link *link, sd_netlink_message *message
 }
 
 static int link_update_name(Link *link, sd_netlink_message *message) {
-        char ifname_from_index[IF_NAMESIZE + 1];
+        char ifname_from_index[IF_NAMESIZE];
         const char *ifname;
         int r;
 
@@ -2229,8 +2229,9 @@ static int link_update_name(Link *link, sd_netlink_message *message) {
         if (streq(ifname, link->ifname))
                 return 0;
 
-        if (!format_ifname(link->ifindex, ifname_from_index))
+        r = format_ifname(link->ifindex, ifname_from_index);
-                return log_link_debug_errno(link, SYNTHETIC_ERRNO(ENXIO), "Could not get interface name for index %i.", link->ifindex);
+        if (r < 0)
+                return log_link_debug_errno(link, r, "Could not get interface name for index %i.", link->ifindex);
 
         if (!streq(ifname, ifname_from_index)) {
                 log_link_debug(link, "New interface name '%s' received from the kernel does not correspond "

src/resolve/resolvectl.c

@@ -187,14 +187,16 @@ static void print_source(uint64_t flags, usec_t rtt) {
 }
 
 static void print_ifindex_comment(int printed_so_far, int ifindex) {
-        char ifname[IF_NAMESIZE + 1];
+        char ifname[IF_NAMESIZE];
+        int r;
 
         if (ifindex <= 0)
                 return;
 
-        if (!format_ifname(ifindex, ifname))
+        r = format_ifname(ifindex, ifname);
-                log_warning_errno(errno, "Failed to resolve interface name for index %i, ignoring: %m", ifindex);
+        if (r < 0)
-        else
+                return (void) log_warning_errno(r, "Failed to resolve interface name for index %i, ignoring: %m", ifindex);
+
         printf("%*s%s-- link: %s%s",
                60 > printed_so_far ? 60 - printed_so_far : 0, " ", /* Align comment to the 60th column */
                ansi_grey(), ifname, ansi_normal());
@@ -1555,15 +1557,16 @@ static int status_ifindex(sd_bus *bus, int ifindex, const char *name, StatusMode
         _cleanup_(link_info_clear) LinkInfo link_info = {};
         _cleanup_(table_unrefp) Table *table = NULL;
         _cleanup_free_ char *p = NULL;
-        char ifi[DECIMAL_STR_MAX(int)], ifname[IF_NAMESIZE + 1] = "";
+        char ifi[DECIMAL_STR_MAX(int)], ifname[IF_NAMESIZE];
         int r;
 
         assert(bus);
         assert(ifindex > 0);
 
         if (!name) {
-                if (!format_ifname(ifindex, ifname))
+                r = format_ifname(ifindex, ifname);
-                        return log_error_errno(errno, "Failed to resolve interface name for %i: %m", ifindex);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to resolve interface name for %i: %m", ifindex);
 
                 name = ifname;
         }

src/resolve/resolved-dns-cache.c

@@ -504,7 +504,6 @@ static int dns_cache_put_positive(
 
         if (DEBUG_LOGGING) {
                 _cleanup_free_ char *t = NULL;
-                char ifname[IF_NAMESIZE + 1];
 
                 (void) in_addr_to_string(i->owner_family, &i->owner_address, &t);
 
@@ -514,7 +513,7 @@ static int dns_cache_put_positive(
                           i->shared_owner ? " shared" : "",
                           dns_resource_key_to_string(i->key, key_str, sizeof key_str),
                           (i->until - timestamp) / USEC_PER_SEC,
-                          i->ifindex == 0 ? "*" : strna(format_ifname(i->ifindex, ifname)),
+                          i->ifindex == 0 ? "*" : FORMAT_IFNAME(i->ifindex),
                           af_to_name_short(i->owner_family),
                           strna(t));
         }

src/shared/format-table.c

@@ -1665,16 +1665,9 @@ static const char *table_data_format(Table *t, TableData *d, bool avoid_uppercas
 
         case TABLE_IFINDEX: {
                 _cleanup_free_ char *p = NULL;
-                char name[IF_NAMESIZE + 1];
 
-                if (format_ifname(d->ifindex, name)) {
+                if (format_ifname_full_alloc(d->ifindex, FORMAT_IFNAME_IFINDEX, &p) < 0)
-                        p = strdup(name);
-                        if (!p)
                         return NULL;
-                } else {
-                        if (asprintf(&p, "%i" , d->ifindex) < 0)
-                                return NULL;
-                }
 
                 d->formatted = TAKE_PTR(p);
                 break;

src/shared/log-link.h

@@ -17,24 +17,6 @@
                 log_interface_full_errno_zerook(ifname, level, _error, __VA_ARGS__); \
         })
 
-#define log_interface_prefix_full_errno_zerook(prefix, ifname_expr, error, fmt, ...) \
-        ({                                                              \
-                int _e = (error);                                       \
-                if (DEBUG_LOGGING)                                      \
-                        log_interface_full_errno_zerook(                \
-                                ifname_expr,                            \
-                                LOG_DEBUG, _e, prefix fmt,              \
-                                ##__VA_ARGS__);                         \
-                -ERRNO_VALUE(_e);                                       \
-        })
-
-#define log_interface_prefix_full_errno(prefix, ifname_expr, error, fmt, ...) \
-        ({                                                              \
-                int _error = (error);                                   \
-                ASSERT_NON_ZERO(_error);                                \
-                log_interface_prefix_full_errno_zerook(prefix, ifname_expr, _error, fmt, ##__VA_ARGS__); \
-        })
-
 /*
  * The following macros append INTERFACE= to the message.
  * The macros require a struct named 'Link' which contains 'char *ifname':

src/shared/netif-naming-scheme.c

@@ -5,6 +5,13 @@
 #include "proc-cmdline.h"
 #include "string-util.h"
 
+#ifdef _DEFAULT_NET_NAMING_SCHEME_TEST
+/* The primary purpose of this check is to verify that _DEFAULT_NET_NAMING_SCHEME_TEST
+ * is a valid identifier. If an invalid name is given during configuration, this will
+ * fail with a name error. */
+assert_cc(_DEFAULT_NET_NAMING_SCHEME_TEST >= 0);
+#endif
+
 static const NamingScheme naming_schemes[] = {
         { "v238", NAMING_V238 },
         { "v239", NAMING_V239 },
@@ -15,19 +22,22 @@ static const NamingScheme naming_schemes[] = {
         { "v247", NAMING_V247 },
         { "v249", NAMING_V249 },
         /* … add more schemes here, as the logic to name devices is updated … */
-        /* also remember to update the list of options in meson_options.txt */
+
+        EXTRA_NET_NAMING_MAP
 };
 
-static const NamingScheme* naming_scheme_from_name(const char *name) {
+const NamingScheme* naming_scheme_from_name(const char *name) {
-        size_t i;
+        /* "latest" may either be defined explicitly by the extra map, in which case we we will find it in
+         * the table like any other name. After iterating through the table, we check for "latest" again,
+         * which means that if not mapped explicitly, it maps to the last defined entry, whatever that is. */
+
+        for (size_t i = 0; i < ELEMENTSOF(naming_schemes); i++)
+                if (streq(naming_schemes[i].name, name))
+                        return naming_schemes + i;
 
         if (streq(name, "latest"))
                 return naming_schemes + ELEMENTSOF(naming_schemes) - 1;
 
-        for (i = 0; i < ELEMENTSOF(naming_schemes); i++)
-                if (streq(naming_schemes[i].name, name))
-                        return naming_schemes + i;
-
         return NULL;
 }
 

src/shared/netif-naming-scheme.h

@@ -46,6 +46,8 @@ typedef enum NamingSchemeFlags {
         NAMING_V247 = NAMING_V245 | NAMING_BRIDGE_NO_SLOT,
         NAMING_V249 = NAMING_V247 | NAMING_SLOT_FUNCTION_ID | NAMING_16BIT_INDEX | NAMING_REPLACE_STRICTLY,
 
+        EXTRA_NET_NAMING_SCHEMES
+
         _NAMING_SCHEME_FLAGS_INVALID = -EINVAL,
 } NamingSchemeFlags;
 
@@ -54,6 +56,7 @@ typedef struct NamingScheme {
         NamingSchemeFlags flags;
 } NamingScheme;
 
+const NamingScheme* naming_scheme_from_name(const char *name);
 const NamingScheme* naming_scheme(void);
 
 static inline bool naming_scheme_has(NamingSchemeFlags flags) {

src/systemd/sd-dhcp-client.h

@@ -135,7 +135,7 @@ int sd_dhcp_client_set_ifindex(
 int sd_dhcp_client_set_ifname(
                 sd_dhcp_client *client,
                 const char *interface_name);
-const char *sd_dhcp_client_get_ifname(sd_dhcp_client *client);
+int sd_dhcp_client_get_ifname(sd_dhcp_client *client, const char **ret);
 int sd_dhcp_client_set_mac(
                 sd_dhcp_client *client,
                 const uint8_t *addr,

src/systemd/sd-dhcp-server.h

@@ -38,7 +38,7 @@ enum {
 int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex);
 
 int sd_dhcp_server_set_ifname(sd_dhcp_server *server, const char *ifname);
-const char *sd_dhcp_server_get_ifname(sd_dhcp_server *server);
+int sd_dhcp_server_get_ifname(sd_dhcp_server *server, const char **ret);
 
 sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server);
 sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server);

src/systemd/sd-dhcp6-client.h

@@ -94,7 +94,7 @@ int sd_dhcp6_client_set_ifindex(
 int sd_dhcp6_client_set_ifname(
                 sd_dhcp6_client *client,
                 const char *interface_name);
-const char * sd_dhcp6_client_get_ifname(sd_dhcp6_client *client);
+int sd_dhcp6_client_get_ifname(sd_dhcp6_client *client, const char **ret);
 int sd_dhcp6_client_set_local_address(
                 sd_dhcp6_client *client,
                 const struct in6_addr *local_address);

src/systemd/sd-ipv4acd.h

@@ -47,7 +47,7 @@ int sd_ipv4acd_set_mac(sd_ipv4acd *acd, const struct ether_addr *addr);
 int sd_ipv4acd_set_ifindex(sd_ipv4acd *acd, int interface_index);
 int sd_ipv4acd_get_ifindex(sd_ipv4acd *acd);
 int sd_ipv4acd_set_ifname(sd_ipv4acd *acd, const char *interface_name);
-const char *sd_ipv4acd_get_ifname(sd_ipv4acd *acd);
+int sd_ipv4acd_get_ifname(sd_ipv4acd *acd, const char **ret);
 int sd_ipv4acd_set_address(sd_ipv4acd *acd, const struct in_addr *address);
 int sd_ipv4acd_is_running(sd_ipv4acd *acd);
 int sd_ipv4acd_start(sd_ipv4acd *acd, bool reset_conflicts);

src/systemd/sd-ipv4ll.h

@@ -47,7 +47,7 @@ int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr);
 int sd_ipv4ll_set_ifindex(sd_ipv4ll *ll, int interface_index);
 int sd_ipv4ll_get_ifindex(sd_ipv4ll *ll);
 int sd_ipv4ll_set_ifname(sd_ipv4ll *ll, const char *interface_name);
-const char *sd_ipv4ll_get_ifname(sd_ipv4ll *ll);
+int sd_ipv4ll_get_ifname(sd_ipv4ll *ll, const char **ret);
 int sd_ipv4ll_set_address(sd_ipv4ll *ll, const struct in_addr *address);
 int sd_ipv4ll_set_address_seed(sd_ipv4ll *ll, uint64_t seed);
 int sd_ipv4ll_is_running(sd_ipv4ll *ll);

src/systemd/sd-lldp-rx.h

@@ -59,7 +59,7 @@ sd_event *sd_lldp_rx_get_event(sd_lldp_rx *lldp_rx);
 int sd_lldp_rx_set_callback(sd_lldp_rx *lldp_rx, sd_lldp_rx_callback_t cb, void *userdata);
 int sd_lldp_rx_set_ifindex(sd_lldp_rx *lldp_rx, int ifindex);
 int sd_lldp_rx_set_ifname(sd_lldp_rx *lldp_rx, const char *ifname);
-const char *sd_lldp_rx_get_ifname(sd_lldp_rx *lldp_rx);
+int sd_lldp_rx_get_ifname(sd_lldp_rx *lldp_rx, const char **ret);
 
 /* Controls how much and what to store in the neighbors database */
 int sd_lldp_rx_set_neighbors_max(sd_lldp_rx *lldp_rx, uint64_t n);

src/systemd/sd-lldp-tx.h

@@ -54,7 +54,7 @@ sd_event *sd_lldp_tx_get_event(sd_lldp_tx *lldp_tx);
 
 int sd_lldp_tx_set_ifindex(sd_lldp_tx *lldp_tx, int ifindex);
 int sd_lldp_tx_set_ifname(sd_lldp_tx *lldp_tx, const char *ifname);
-const char *sd_lldp_tx_get_ifname(sd_lldp_tx *lldp_tx);
+int sd_lldp_tx_get_ifname(sd_lldp_tx *lldp_tx, const char **ret);
 
 int sd_lldp_tx_set_multicast_mode(sd_lldp_tx *lldp_tx, sd_lldp_multicast_mode_t mode);
 int sd_lldp_tx_set_hwaddr(sd_lldp_tx *lldp_tx, const struct ether_addr *hwaddr);

src/systemd/sd-ndisc.h

@@ -79,7 +79,7 @@ sd_event *sd_ndisc_get_event(sd_ndisc *nd);
 int sd_ndisc_set_callback(sd_ndisc *nd, sd_ndisc_callback_t cb, void *userdata);
 int sd_ndisc_set_ifindex(sd_ndisc *nd, int interface_index);
 int sd_ndisc_set_ifname(sd_ndisc *nd, const char *interface_name);
-const char *sd_ndisc_get_ifname(sd_ndisc *nd);
+int sd_ndisc_get_ifname(sd_ndisc *nd, const char **ret);
 int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr);
 
 int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *ret);

src/systemd/sd-radv.h

@@ -54,7 +54,7 @@ int sd_radv_is_running(sd_radv *ra);
 
 int sd_radv_set_ifindex(sd_radv *ra, int interface_index);
 int sd_radv_set_ifname(sd_radv *ra, const char *interface_name);
-const char *sd_radv_get_ifname(sd_radv *ra);
+int sd_radv_get_ifname(sd_radv *ra, const char **ret);
 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr);
 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu);
 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit);

src/test/meson.build

@@ -429,6 +429,8 @@ tests += [
 
         [['src/test/test-firewall-util.c']],
 
+        [['src/test/test-net-naming-scheme.c']],
+
         [['src/test/test-netlink-manual.c'],
          [],
          [libkmod],

src/test/test-net-naming-scheme.c

@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "netif-naming-scheme.h"
+#include "string-util.h"
+#include "tests.h"
+
+static void test_default_net_naming_scheme(void) {
+        log_info("/* %s */", __func__);
+
+        const NamingScheme *n;
+        assert_se(n = naming_scheme_from_name(DEFAULT_NET_NAMING_SCHEME));
+        log_info("default → %s", n->name);
+}
+
+static void test_naming_scheme_conversions(void) {
+        log_info("/* %s */", __func__);
+
+        const NamingScheme *n;
+        assert_se(n = naming_scheme_from_name("latest"));
+        log_info("latest → %s", n->name);
+
+        assert_se(n = naming_scheme_from_name("v238"));
+        assert_se(streq(n->name, "v238"));
+}
+
+int main(int argc, char **argv) {
+        test_setup_logging(LOG_INFO);
+
+        test_default_net_naming_scheme();
+        test_naming_scheme_conversions();
+}

src/test/test-nss-hosts.c

@@ -41,14 +41,12 @@ static const char* af_to_string(int family, char *buf, size_t buf_len) {
 }
 
 static int print_gaih_addrtuples(const struct gaih_addrtuple *tuples) {
-        int n = 0;
+        int r, n = 0;
 
         for (const struct gaih_addrtuple *it = tuples; it; it = it->next) {
                 _cleanup_free_ char *a = NULL;
                 union in_addr_union u;
-                int r;
                 char family_name[DECIMAL_STR_MAX(int)];
-                char ifname[IF_NAMESIZE + 1];
 
                 memcpy(&u, it->addr, 16);
                 r = in_addr_to_string(it->family, &u, &a);
@@ -56,20 +54,12 @@ static int print_gaih_addrtuples(const struct gaih_addrtuple *tuples) {
                 if (r == -EAFNOSUPPORT)
                         assert_se(a = hexmem(it->addr, 16));
 
-                if (it->scopeid == 0)
+                log_info("        \"%s\" %s %s %s",
-                        goto numerical_index;
-
-                if (!format_ifname(it->scopeid, ifname)) {
-                        log_warning_errno(errno, "if_indextoname(%d) failed: %m", it->scopeid);
-                numerical_index:
-                        xsprintf(ifname, "%i", it->scopeid);
-                };
-
-                log_info("        \"%s\" %s %s %%%s",
                          it->name,
                          af_to_string(it->family, family_name, sizeof family_name),
                          a,
-                         ifname);
+                         FORMAT_IFNAME_FULL(it->scopeid, FORMAT_IFNAME_IFINDEX_WITH_PERCENT));
+
                 n++;
         }
         return n;

src/test/test-string-util.c

@@ -1000,6 +1000,33 @@ static void test_strextendf(void) {
         assert_se(streq(p, "<77>,<99>,<                                                                              88>,<00001234>"));
 }
 
+static void test_streq_skip_trailing_chars(void) {
+        log_info("/* %s */", __func__);
+
+        /* NULL is WHITESPACE by default*/
+        assert_se(streq_skip_trailing_chars("foo bar", "foo bar", NULL));
+        assert_se(streq_skip_trailing_chars("foo", "foo", NULL));
+        assert_se(streq_skip_trailing_chars("foo bar      ", "foo bar", NULL));
+        assert_se(streq_skip_trailing_chars("foo bar", "foo bar\t\t", NULL));
+        assert_se(streq_skip_trailing_chars("foo bar  ", "foo bar\t\t", NULL));
+        assert_se(streq_skip_trailing_chars("foo\nbar", "foo\nbar", NULL));
+        assert_se(streq_skip_trailing_chars("\t\tfoo bar", "\t\tfoo bar", NULL));
+        assert_se(streq_skip_trailing_chars(" foo bar\t", " foo bar\n", NULL));
+
+        assert_se(!streq_skip_trailing_chars("foobar", "foo bar", NULL));
+        assert_se(!streq_skip_trailing_chars("foo\nbar", "foo\tbar", NULL));
+        assert_se(!streq_skip_trailing_chars("\t\nfoo bar", "\t foo bar", NULL));
+
+        assert_se(streq_skip_trailing_chars("foo bar      ", "foo bar", WHITESPACE));
+        assert_se(!streq_skip_trailing_chars("foo bar      ", "foo bar", NEWLINE));
+
+        assert_se(streq_skip_trailing_chars(NULL, NULL, NULL));
+        assert_se(streq_skip_trailing_chars("", "", NULL));
+        assert_se(!streq_skip_trailing_chars(NULL, "foo bar", NULL));
+        assert_se(!streq_skip_trailing_chars("foo", NULL, NULL));
+        assert_se(!streq_skip_trailing_chars("", "f", NULL));
+}
+
 int main(int argc, char *argv[]) {
         test_setup_logging(LOG_DEBUG);
 
@@ -1039,6 +1066,7 @@ int main(int argc, char *argv[]) {
         test_string_contains_word();
         test_strverscmp_improved();
         test_strextendf();
+        test_streq_skip_trailing_chars();
 
         return 0;
 }