Ticket #2818: 20081011-dladdr.diff

src/system/libroot/posix/dlfcn.c

@@ -72 +72 @@
 }
 
 
+int
+dladdr(void *addr, Dl_info *info)
+{
+    char        curSymName[NAME_MAX];
+    static char     symName[NAME_MAX];
+    static char     imageName[MAXPATHLEN];
+    void    *symLocation;
+    int32   cookie;
+    int32   symType, symNameLength;
+    uint32  symIndex;
+    image_info  imageInfo;
+
+    if(info == NULL)
+        return 0;
+
+    imageName[0] = '\0';
+    symName[0] = '\0';
+    info->dli_fname = imageName;
+    info->dli_saddr = NULL;
+    info->dli_sname = symName;
+
+    cookie = 0;
+    while (get_next_image_info(0, &cookie, &imageInfo) == B_OK) {
+        // check if the image holds the symbol
+        if( (addr_t) addr >= (addr_t)imageInfo.text
+            && (addr_t) addr < (addr_t)imageInfo.text + imageInfo.text_size)  {
+            strncpy(imageName, imageInfo.name, MAXPATHLEN);
+            imageName[MAXPATHLEN-1] = '\0';
+            info->dli_fbase = imageInfo.text;
+            symIndex = 0;
+            symNameLength = NAME_MAX;
+
+            while(get_nth_image_symbol(imageInfo.id,
+                symIndex, curSymName, &symNameLength,
+                &symType, &symLocation) == B_OK) {
+                // check if symbol is the nearest until now
+                if(symType == B_SYMBOL_TYPE_TEXT
+                    && symLocation <= addr
+                    && symLocation >= info->dli_saddr) {
+                    strncpy(symName, curSymName, NAME_MAX);
+                    symName[NAME_MAX-1] = '\0';
+                    info->dli_saddr = symLocation;
+
+                    // stop here if exact match 
+                    if(info->dli_saddr == addr)
+                        return 1;
+                }
+                symIndex++;
+                symNameLength = NAME_MAX;
+            }
+            break;
+        }
+
+    }
+
+    if(info->dli_saddr != NULL)
+        return 1;
+    else
+        return 0;
+}
+
+
 // __libc_dl*** wrappers
 // We use a mixed glibc / bsd libc, and glibc wants these
 void *__libc_dlopen(const char *name);

headers/posix/dlfcn.h

@@ -17 +17 @@
 extern "C" {
 #endif
 
+/* This is a gnu extension for the dladdr function */
+typedef struct 
+{
+   const char *dli_fname;  /* Filename of defining object */
+   void *dli_fbase;        /* Load address of that object */
+   const char *dli_sname;  /* Name of nearest lower symbol */
+   void *dli_saddr;        /* Exact value of nearest symbol */
+} Dl_info;
+
 extern int  dlclose(void *image);
 extern char *dlerror(void);
 extern void *dlopen(const char *path, int mode);
 extern void *dlsym(void *image, const char *symbolName);
+extern int  dladdr(void *addr, Dl_info *info);
 
 #ifdef __cplusplus
 }