tree-wide: assorted fixes/workarounds for supporting musl (#39687)

src/basic/build-path.c

@@ -34,11 +34,11 @@ static int get_runpath_from_dynamic(const ElfW(Dyn) *d, ElfW(Addr) bias, const c
                         break;
 
                 case DT_STRTAB:
-                        /* On MIPS and RISC-V DT_STRTAB records an offset, not a valid address, so it has to be adjusted
-                         * using the bias calculated earlier. */
+                        /* On MIPS, RISC-V, or with musl, DT_STRTAB records an offset, not a valid address,
+                         * so it has to be adjusted using the bias calculated earlier. */
                         if (d->d_un.d_val != 0)
                                 strtab = (const char *) ((uintptr_t) d->d_un.d_val
-#if defined(__mips__) || defined(__riscv)
+#if defined(__mips__) || defined(__riscv) || !defined(__GLIBC__)
                                          + bias
 #endif
                                 );

src/basic/format-util.h

@@ -39,12 +39,18 @@ assert_cc(sizeof(gid_t) == sizeof(uint32_t));
 #  error Unknown timex member size
 #endif
 
-#if SIZEOF_RLIM_T == 8
-#  define RLIM_FMT "%" PRIu64
-#elif SIZEOF_RLIM_T == 4
-#  define RLIM_FMT "%" PRIu32
+#ifdef __GLIBC__
+#  if SIZEOF_RLIM_T == 8
+#    define RLIM_FMT "%" PRIu64
+#  elif SIZEOF_RLIM_T == 4
+#    define RLIM_FMT "%" PRIu32
+#  else
+#    error Unknown rlim_t size
+#  endif
 #else
-#  error Unknown rlim_t size
+/* Assume musl, and it unconditionally uses unsigned long long. */
+assert_cc(SIZEOF_RLIM_T == 8);
+#  define RLIM_FMT "%llu"
 #endif
 
 #if SIZEOF_DEV_T == 8

src/basic/hostname-util.c

@@ -94,8 +94,8 @@ bool hostname_is_valid(const char *s, ValidHostnameFlags flags) {
         if (hyphen)
                 return false;
 
-        if (p-s > HOST_NAME_MAX) /* Note that HOST_NAME_MAX is 64 on Linux, but DNS allows domain names up to
-                                  * 255 characters */
+        /* Note that host name max is 64 on Linux, but DNS allows domain names up to 255 characters. */
+        if (p - s > (ssize_t) LINUX_HOST_NAME_MAX)
                 return false;
 
         return true;
@@ -107,7 +107,7 @@ char* hostname_cleanup(char *s) {
 
         assert(s);
 
-        for (p = s, d = s, dot = hyphen = true; *p && d - s < HOST_NAME_MAX; p++)
+        for (p = s, d = s, dot = hyphen = true; *p && d - s < (ssize_t) LINUX_HOST_NAME_MAX; p++)
                 if (*p == '.') {
                         if (dot || hyphen)
                                 continue;

src/basic/hostname-util.h

@@ -4,6 +4,9 @@
 #include "basic-forward.h"
 #include "strv.h"
 
+/* HOST_NAME_MAX should be 64 on linux, but musl uses the one by POSIX (255). */
+#define LINUX_HOST_NAME_MAX CONST_MIN((size_t) HOST_NAME_MAX, (size_t) 64)
+
 char* get_default_hostname_raw(void);
 
 bool valid_ldh_char(char c) _const_;