libbacktrace: support short read

	* read.c (backtrace_get_view): Support short read.

diff --git a/libbacktrace/ChangeLog b/libbacktrace/ChangeLog
index 277d7c01ff32367da57a68c1b3bd5ee9f00300e9..4b4f574fc754fc8c694c79fc5d24e282ef00232b 100644 (file)
--- a/libbacktrace/ChangeLog
+++ b/libbacktrace/ChangeLog
@@ -1,3 +1,7 @@
+2020-05-09  Ian Lance Taylor  <iant@golang.org>
+
+       * read.c (backtrace_get_view): Support short read.
+
 2020-05-09  Ian Lance Taylor  <iant@golang.org>
 
        * elf.c (elf_add): If debug sections are very large or far apart,

diff --git a/libbacktrace/read.c b/libbacktrace/read.c
index 57e4701bbeb9b2fbaeeb2d824a4ac5919b8503cd..1a6052bf61396e3786dd7810854f462635cadea2 100644 (file)
--- a/libbacktrace/read.c
+++ b/libbacktrace/read.c
@@ -50,7 +50,8 @@ backtrace_get_view (struct backtrace_state *state, int descriptor,
                    backtrace_error_callback error_callback,
                    void *data, struct backtrace_view *view)
 {
-  ssize_t got;
+  uint64_t got;
+  ssize_t r;
 
   if ((uint64_t) (size_t) size != size)
     {
@@ -70,15 +71,22 @@ backtrace_get_view (struct backtrace_state *state, int descriptor,
   view->data = view->base;
   view->len = size;
 
-  got = read (descriptor, view->base, size);
-  if (got < 0)
+  got = 0;
+  while (got < size)
     {
-      error_callback (data, "read", errno);
-      free (view->base);
-      return 0;
+      r = read (descriptor, view->base, size - got);
+      if (r < 0)
+       {
+         error_callback (data, "read", errno);
+         free (view->base);
+         return 0;
+       }
+      if (r == 0)
+       break;
+      got += (uint64_t) r;
     }
 
-  if ((size_t) got < size)
+  if (got < size)
     {
       error_callback (data, "file too short", 0);
       free (view->base);