BUILD: tools: unbreak resolve_sym_name() on non-GNU platforms

resolve_sym_name() doesn't build when USE_DL is set on non-GNU platforms
because "Elf(W)" isn't defined. Since it's only used for dladdr1(), let's
refactor all this so that we can completely ifdef out that part on other
platforms. Now we have a separate function to perform the call depending
on the platform and it only returns the size when available.

(cherry picked from commit 9133e48f2a6fa9deccfe02798dcb2f2abd26ed9e)
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/src/standard.c b/src/standard.c
index 4c1bcd6..e950ca1 100644 (file)
--- a/src/standard.c
+++ b/src/standard.c
@@ -4343,6 +4343,27 @@ void debug_hexdump(FILE *out, const char *pfx, const char *buf,
        }
 }
 
+#ifdef USE_DL
+/* calls dladdr() or dladdr1() on <addr> and <dli>. If dladdr1 is available,
+ * also returns the symbol size in <size>, otherwise returns 0 there.
+ */
+static int dladdr_and_size(const void *addr, Dl_info *dli, size_t *size)
+{
+       int ret;
+#ifdef __USE_GNU // most detailed one
+       const ElfW(Sym) *sym;
+
+       ret = dladdr1(addr, dli, (void **)&sym, RTLD_DL_SYMENT);
+       if (ret)
+               *size = sym ? sym->st_size : 0;
+#else
+       ret = dladdr(addr, dli);
+       *size = 0;
+#endif
+       return ret;
+}
+#endif
+
 /* Tries to append to buffer <buf> some indications about the symbol at address
  * <addr> using the following form:
  *   lib:+0xoffset              (unresolvable address from lib's base)
@@ -4386,7 +4407,7 @@ void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
 
 #ifdef USE_DL
        Dl_info dli, dli_main;
-       const ElfW(Sym) *sym;
+       size_t size;
        const char *fname, *p;
 #endif
        int i;
@@ -4403,14 +4424,8 @@ void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
 
 #ifdef USE_DL
        /* Now let's try to be smarter */
-#ifdef __USE_GNU // most detailed one
-       if (!dladdr1(addr, &dli, (void **)&sym, RTLD_DL_SYMENT))
-               goto unknown;
-#else
-       if (!dladdr(addr, &dli))
+       if (!dladdr_and_size(addr, &dli, &size))
                goto unknown;
-       sym = NULL;
-#endif
 
        /* 1. prefix the library name if it's not the same object as the one
         * that contains the main function. The name is picked between last '/'
@@ -4437,8 +4452,8 @@ void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
                chunk_appendf(buf, "%s", dli.dli_sname);
                if (addr != dli.dli_saddr) {
                        chunk_appendf(buf, "+%#lx", (long)(addr - dli.dli_saddr));
-                       if (sym)
-                               chunk_appendf(buf, "/%#lx", (long)sym->st_size);
+                       if (size)
+                               chunk_appendf(buf, "/%#lx", (long)size);
                }
                return dli.dli_saddr;
        }