Refactor offset string printing out of ELF and DWARF lookups

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/lib/so-info.c b/lib/so-info.c
index eca53cfbd79694898becae3bff00f953205eb33e..6998fbfbf0328700c1bd8ce925a62c2b38e1dfd2 100644 (file)
--- a/lib/so-info.c
+++ b/lib/so-info.c
@@ -536,6 +536,56 @@ void source_location_destroy(struct source_location *src_loc)
        free(src_loc->filename);
        g_free(src_loc);
 }
+/**
+ * Append a string representation of an address offset to an existing
+ * string.
+ *
+ * On success, the out parameter `result` will contain the base string
+ * followed by the offset string of the form "+0x1234". On failure,
+ * `result` remains unchanged.
+ *
+ * @param base_str     The string to which to append an offset string
+ * @param low_addr     The lower virtual memory address, the base from
+ *                     which the offset is computed
+ * @param high_addr    The higher virtual memory address
+ * @param result       Out parameter, the base string followed by the
+ *                     offset string
+ * @returns            0 on success, -1 on failure
+ */
+static
+int so_info_append_offset_str(const char *base_str, uint64_t low_addr,
+                               uint64_t high_addr, char **result)
+{
+       int ret;
+       uint64_t offset;
+       char *_result = NULL;
+       char offset_str[ADDR_STR_LEN];
+
+       if (!base_str || !result) {
+               goto error;
+       }
+
+       offset = high_addr - low_addr;
+
+       _result = malloc(strlen(base_str) + ADDR_STR_LEN);
+       if (!_result) {
+               goto error;
+       }
+
+       ret = snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64, offset);
+       if (ret < 0) {
+               goto error;
+       }
+       strcpy(_result, base_str);
+       strcat(_result, offset_str);
+       *result = _result;
+
+       return 0;
+
+error:
+       free(_result);
+       return -1;
+}
 
 /**
  * Try to find the symbol closest to an address within a given ELF
@@ -670,8 +720,6 @@ int so_info_lookup_elf_function_name(struct so_info *so, uint64_t addr,
        GElf_Sym *sym = NULL;
        GElf_Shdr *shdr = NULL;
        char *sym_name = NULL;
-       char *_func_name = NULL;
-       char offset_str[ADDR_STR_LEN];
 
        /* Set ELF file if it hasn't been accessed yet. */
        if (!so->elf_file) {
@@ -704,16 +752,11 @@ int so_info_lookup_elf_function_name(struct so_info *so, uint64_t addr,
                        goto error;
                }
 
-               snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64,
-                               addr - sym->st_value);
-               _func_name = malloc(strlen(sym_name) + ADDR_STR_LEN);
-               if (!_func_name) {
+               ret = so_info_append_offset_str(sym_name, sym->st_value, addr,
+                                               func_name);
+               if (ret) {
                        goto error;
                }
-
-               strcpy(_func_name, sym_name);
-               strcat(_func_name, offset_str);
-               *func_name = _func_name;
        }
 
        g_free(shdr);
@@ -723,7 +766,6 @@ int so_info_lookup_elf_function_name(struct so_info *so, uint64_t addr,
 error:
        g_free(shdr);
        g_free(sym);
-       free(_func_name);
        return -1;
 }
 
@@ -745,10 +787,6 @@ int so_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
                char **func_name)
 {
        int ret = 0, found = 0;
-       uint64_t low_addr = 0;
-       char *die_name = NULL;
-       char *_func_name = NULL;
-       char offset_str[ADDR_STR_LEN];
        struct bt_dwarf_die *die = NULL;
 
        if (!cu || !func_name) {
@@ -781,6 +819,9 @@ int so_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
        }
 
        if (found) {
+               uint64_t low_addr = 0;
+               char *die_name = NULL;
+
                ret = bt_dwarf_die_get_name(die, &die_name);
                if (ret) {
                        goto error;
@@ -791,17 +832,11 @@ int so_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
                        goto error;
                }
 
-               snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64,
-                               addr - low_addr);
-               _func_name = malloc(strlen(die_name) + ADDR_STR_LEN);
-               if (!_func_name) {
+               ret = so_info_append_offset_str(die_name, low_addr, addr,
+                                               func_name);
+               if (ret) {
                        goto error;
                }
-
-               strcpy(_func_name, die_name);
-               strcat(_func_name, offset_str);
-
-               *func_name = _func_name;
        }
 
        bt_dwarf_die_destroy(die);