[pypy-commit] pypy default: introduce read_exactly as proposed by njs, handles EINTR

[plan_rich]

Author: Richard Plangger <planri...@gmail.com>
Branch: 
Changeset: r91526:9a792fd023fd
Date: 2017-06-05 10:00 -0400
http://bitbucket.org/pypy/pypy/changeset/9a792fd023fd/

Log:    introduce read_exactly as proposed by njs, handles EINTR

diff --git a/rpython/rlib/rvmprof/src/shared/symboltable.c 
b/rpython/rlib/rvmprof/src/shared/symboltable.c
--- a/rpython/rlib/rvmprof/src/shared/symboltable.c
+++ b/rpython/rlib/rvmprof/src/shared/symboltable.c
@@ -207,7 +207,9 @@
 }
 #endif
 
+static
 struct backtrace_state * bstate = NULL;
+
 int vmp_resolve_addr(void * addr, char * name, int name_len, int * lineno, 
char * srcfile, int srcfile_len) {
 #ifdef __APPLE__
     Dl_info dlinfo;
@@ -303,10 +305,34 @@
     lseek(fileno, pos_before, SEEK_SET);
 }
 
+static
+int cannot_read_profile = 0;
+
+ssize_t read_exactly(int fileno, void * buf, ssize_t size) {
+    assert(size >= 0 && "size parameter must be positive");
+
+    ssize_t r = 0;
+    if ((r = read(fileno, buf, (size_t)size)) == size) {
+        return r;
+    }
+
+    if (r == -1) {
+        if (errno == EINTR) {
+            if ((r = read(fileno, buf, (size_t)size)) == size) {
+                return r;
+            }
+        }
+    }
+
+    fprintf(stderr, "unhandled error in read_exactly. cannot proceed! could 
not read %d bytes", size);
+    cannot_read_profile = 1;
+    return -1;
+}
+
 int _skip_string(int fileno)
 {
     long chars;
-    ssize_t count = read(fileno, &chars, sizeof(long));
+    ssize_t count = read_exactly(fileno, &chars, sizeof(long));
     //LOG("reading string of %d chars\n", chars);
     if (count <= 0) {
         return 1;
@@ -319,7 +345,7 @@
 int _skip_header(int fileno, int * version, int * flags)
 {
     unsigned char r[4];
-    (void)read(fileno, r, 4);
+    (void)read_exactly(fileno, r, 4);
     unsigned char count = r[3];
     *version = (r[0] & 0xff) << 8 | (r[1] & 0xff);
     *flags = r[2];
@@ -330,14 +356,14 @@
 long _read_word(int fileno)
 {
     long w;
-    (void)read(fileno, &w, WORD_SIZE);
+    (void)read_exactly(fileno, &w, WORD_SIZE);
     return w;
 }
 
 void * _read_addr(int fileno)
 {
     void * a;
-    (void)read(fileno, &a, ADDR_SIZE);
+    (void)read_exactly(fileno, &a, ADDR_SIZE);
     return a;
 }
 
@@ -378,7 +404,11 @@
     lseek(fileno, 5*WORD_SIZE, SEEK_SET);
 
     while (1) {
-        count = read(fileno, &marker, 1);
+        if (cannot_read_profile == 1) {
+            cannot_read_profile = 0;
+            break;
+        }
+        count = read_exactly(fileno, &marker, 1);
         if (count <= 0) {
             break;
         }
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