Fix: prevent uninitialized use of elf_file

[babeltrace.git] / lib / so-info.c

diff --git a/lib/so-info.c b/lib/so-info.c
index 404425dcf0ba7e98808427f8a4ea28ed9392d367..3a603b8f1561f0b2c52cb8e2b5765a559b9501b3 100644 (file)
--- a/lib/so-info.c
+++ b/lib/so-info.c
@@ -40,6 +40,7 @@
 #include <babeltrace/so-info.h>
 #include <babeltrace/crc32.h>
 #include <babeltrace/babeltrace-internal.h>
+#include <babeltrace/utils.h>
 
 /*
  * An address printed in hex is at most 20 bytes (16 for 64-bits +
@@ -64,10 +65,9 @@ int so_info_init(void)
 
 BT_HIDDEN
 struct so_info *so_info_create(const char *path, uint64_t low_addr,
-               uint64_t memsz)
+               uint64_t memsz, bool is_pic)
 {
        struct so_info *so = NULL;
-       GElf_Ehdr *ehdr = NULL;
 
        if (!path) {
                goto error;
@@ -83,46 +83,14 @@ struct so_info *so_info_create(const char *path, uint64_t low_addr,
                goto error;
        }
 
-       so->elf_fd = open(path, O_RDONLY);
-       if (so->elf_fd < 0) {
-               fprintf(stderr, "Failed to open %s\n", path);
-               goto error;
-       }
-
-       so->elf_file = elf_begin(so->elf_fd, ELF_C_READ, NULL);
-       if (!so->elf_file) {
-               fprintf(stderr, "elf_begin failed: %s\n", elf_errmsg(-1));
-               goto error;
-       }
-
-       if (elf_kind(so->elf_file) != ELF_K_ELF) {
-               fprintf(stderr, "Error: %s is not an ELF object\n",
-                               so->elf_path);
-               goto error;
-       }
-
-       ehdr = g_new0(GElf_Ehdr, 1);
-       if (!ehdr) {
-               goto error;
-       }
-
-       if (!gelf_getehdr(so->elf_file, ehdr)) {
-               fprintf(stderr, "Error: couldn't get ehdr for %s\n",
-                               so->elf_path);
-               goto error;
-       }
-
-       /* Position independent code has an e_type value of ET_DYN. */
-       so->is_pic = ehdr->e_type == ET_DYN;
+       so->is_pic = is_pic;
        so->memsz = memsz;
        so->low_addr = low_addr;
        so->high_addr = so->low_addr + so->memsz;
 
-       g_free(ehdr);
        return so;
 
 error:
-       g_free(ehdr);
        so_info_destroy(so);
        return NULL;
 }
@@ -149,6 +117,7 @@ void so_info_destroy(struct so_info *so)
        g_free(so);
 }
 
+
 BT_HIDDEN
 int so_info_set_build_id(struct so_info *so, uint8_t *build_id,
                size_t build_id_len)
@@ -512,6 +481,51 @@ end:
        return ret;
 }
 
+/**
+ * Initialize the ELF file for a given executable.
+ *
+ * @param so   so_info instance
+ * @returns    0 on success, -1 on failure
+ */
+static
+int so_info_set_elf_file(struct so_info *so)
+{
+       int elf_fd;
+       Elf *elf_file = NULL;
+
+       if (!so) {
+               goto error;
+       }
+
+       elf_fd = open(so->elf_path, O_RDONLY);
+       if (elf_fd < 0) {
+               fprintf(stderr, "Failed to open %s\n", so->elf_path);
+               goto error;
+       }
+
+       elf_file = elf_begin(elf_fd, ELF_C_READ, NULL);
+       if (!elf_file) {
+               fprintf(stderr, "elf_begin failed: %s\n", elf_errmsg(-1));
+               goto error;
+       }
+
+       if (elf_kind(elf_file) != ELF_K_ELF) {
+               fprintf(stderr, "Error: %s is not an ELF object\n",
+                               so->elf_path);
+               goto error;
+       }
+
+       so->elf_fd = elf_fd;
+       so->elf_file = elf_file;
+       return 0;
+
+error:
+       close(elf_fd);
+       elf_end(elf_file);
+       return -1;
+}
+
+
 BT_HIDDEN
 void source_location_destroy(struct source_location *src_loc)
 {
@@ -659,6 +673,15 @@ int so_info_lookup_elf_function_name(struct so_info *so, uint64_t addr,
        char *_func_name = NULL;
        char offset_str[ADDR_STR_LEN];
 
+       /* Set ELF file if it hasn't been accessed yet. */
+       if (!so->elf_file) {
+               ret = so_info_set_elf_file(so);
+               if (ret) {
+                       /* Failed to set ELF file. */
+                       goto error;
+               }
+       }
+
        scn = elf_nextscn(so->elf_file, scn);
        if (!scn) {
                goto error;
@@ -826,11 +849,12 @@ error:
 }
 
 BT_HIDDEN
-int so_info_lookup_function_name(struct so_info *so, uint64_t addr,
+int so_info_lookup_function_name(struct so_info *so, uint64_t ip,
                char **func_name)
 {
        int ret = 0;
        char *_func_name = NULL;
+       uint64_t relative_addr;
 
        if (!so || !func_name) {
                goto error;
@@ -845,32 +869,46 @@ int so_info_lookup_function_name(struct so_info *so, uint64_t addr,
                }
        }
 
-       if (!so_info_has_address(so, addr)) {
+       if (!so_info_has_address(so, ip)) {
                goto error;
        }
 
+       relative_addr = ip - so->low_addr;
        /*
         * Addresses in ELF and DWARF are relative to base address for
         * PIC, so make the address argument relative too if needed.
         */
-       if (so->is_pic) {
-               addr -= so->low_addr;
-       }
-
        if (so->is_elf_only) {
-               ret = so_info_lookup_elf_function_name(so, addr, &_func_name);
+               ret = so_info_lookup_elf_function_name(so,
+                               so->is_pic ? relative_addr : ip,
+                               &_func_name);
        } else {
-               ret = so_info_lookup_dwarf_function_name(so, addr, &_func_name);
+               ret = so_info_lookup_dwarf_function_name(so,
+                               so->is_pic ? relative_addr : ip,
+                               &_func_name);
        }
 
        if (ret) {
                goto error;
        }
 
-       if (_func_name) {
-               *func_name = _func_name;
+       if (!_func_name) {
+               /*
+                * Can't map to a function; fallback to a generic output of the
+                * form binary+/@address.
+                *
+                * FIXME check position independence flag.
+                */
+               const char *binary_name = get_filename_from_path(so->elf_path);
+
+               ret = asprintf(&_func_name, "%s+%#0" PRIx64, binary_name,
+                               relative_addr);
+               if (!_func_name) {
+                       goto error;
+               }
        }
 
+       *func_name = _func_name;
        return 0;
 
 error: