malloc: simplify nasm_malloc code, add nasm_strcatn()

Simplify the nasm_malloc() code by moving the pointer check into a
common subroutine.

We can now issue a filename error even for failures like malloc().

Add support for the gcc sentinel attribute (verify that a list ends
with NULL).

Add a handful of safe_alloc attributes.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

aclocal.m4

@@ -106,10 +106,11 @@ AC_DEFUN(PA_FUNC_ATTRIBUTE,
 AC_INCLUDES_DEFAULT
 extern ifelse([$3],[],[void *],[$3])  __attribute__(($1$2))
   bar(ifelse([$4],[],[int],[$4]));
-void *foo(void);
-void *foo(void)
+ifelse([$3],[],[void *],[$3]) foo(void);
+ifelse([$3],[],[void *],[$3]) foo(void)
 {
-	return bar(ifelse([$5],[],[1],[$5]));
+	ifelse([$3],[void],[],[return])
+		bar(ifelse([$5],[],[1],[$5]));
 }
  ])],
  [AC_MSG_RESULT([yes])

configure.ac

@@ -220,6 +220,7 @@ PA_FUNC_ATTRIBUTE(noreturn)
 PA_FUNC_ATTRIBUTE(returns_nonnull)
 PA_FUNC_ATTRIBUTE(malloc)
 PA_FUNC_ATTRIBUTE(alloc_size, (1))
+PA_FUNC_ATTRIBUTE(sentinel,,, [const char *, ...], ["a","b",NULL])
 PA_FUNC_ATTRIBUTE(format, [(printf,1,2)], int, [const char *, ...], ["%d",1])
 PA_FUNC_ATTRIBUTE(const)
 PA_FUNC_ATTRIBUTE(pure)

include/compiler.h

@@ -264,7 +264,7 @@ size_t strnlen(const char *s, size_t maxlen);
 #ifdef HAVE_FUNC_ATTRIBUTE_MALLOC
 # define safe_alloc never_null __attribute__((malloc))
 #else
-# define safe_alloc
+# define safe_alloc never_null
 #endif
 
 #ifdef HAVE_FUNC_ATTRIBUTE_ALLOC_SIZE
@@ -277,6 +277,12 @@ size_t strnlen(const char *s, size_t maxlen);
 # define safe_realloc(s) never_null
 #endif
 
+#ifdef HAVE_FUNC_ATTRIBUTE_SENTINEL
+# define end_with_null __attribute__((sentinel))
+#else
+# define end_with_null
+#endif
+
 /*
  * How to tell the compiler that a function doesn't return
  */

include/nasmlib.h

@@ -79,6 +79,8 @@ void * safe_realloc(2) nasm_realloc(void *, size_t);
 void nasm_free(void *);
 char * safe_alloc nasm_strdup(const char *);
 char * safe_alloc nasm_strndup(const char *, size_t);
+char * safe_alloc nasm_strcat(const char *one, const char *two);
+char * safe_alloc end_with_null nasm_strcatn(const char *one, ...);
 
 /* Assert the argument is a pointer without evaluating it */
 #define nasm_assert_pointer(p) ((void)sizeof(*(p)))
@@ -282,8 +284,6 @@ void src_set(int32_t line, const char *filename);
  */
 int32_t src_get(int32_t *xline, const char **xname);
 
-char *nasm_strcat(const char *one, const char *two);
-
 char *nasm_skip_spaces(const char *p);
 char *nasm_skip_word(const char *p);
 char *nasm_zap_spaces_fwd(char *p);

nasmlib/malloc.c

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------- *
- *   
- *   Copyright 1996-2016 The NASM Authors - All Rights Reserved
+ *
+ *   Copyright 1996-2018 The NASM Authors - All Rights Reserved
  *   See the file AUTHORS included with the NASM distribution for
  *   the specific copyright holders.
  *
@@ -14,7 +14,7 @@
  *     copyright notice, this list of conditions and the following
  *     disclaimer in the documentation and/or other materials provided
  *     with the distribution.
- *     
+ *
  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
@@ -42,33 +42,36 @@
 #include "nasmlib.h"
 #include "error.h"
 
+static no_return nasm_alloc_failed(void)
+{
+    nasm_fatal(0, "out of memory");
+}
+
+static inline void *validate_ptr(void *p)
+{
+    if (unlikely(!p))
+        nasm_alloc_failed();
+    return p;
+}
+
 void *nasm_malloc(size_t size)
 {
-    void *p = malloc(size);
-    if (!p)
-        nasm_fatal(ERR_NOFILE, "out of memory");
-    return p;
+    return validate_ptr(malloc(size));
 }
 
 void *nasm_calloc(size_t size, size_t nelem)
 {
-    void *p = calloc(size, nelem);
-    if (!p)
-        nasm_fatal(ERR_NOFILE, "out of memory");
-    return p;
+    return validate_ptr(calloc(size, nelem));
 }
 
 void *nasm_zalloc(size_t size)
 {
-    return nasm_calloc(size, 1);
+    return validate_ptr(calloc(1, size));
 }
 
 void *nasm_realloc(void *q, size_t size)
 {
-    void *p = q ? realloc(q, size) : malloc(size);
-    if (!p)
-        nasm_fatal(ERR_NOFILE, "out of memory");
-    return p;
+    return validate_ptr(q ? realloc(q, size) : malloc(size));
 }
 
 void nasm_free(void *q)
@@ -106,3 +109,55 @@ char *nasm_strcat(const char *one, const char *two)
     memcpy(rslt + l1, two, l2+1);
     return rslt;
 }
+
+char *nasm_strcatn(const char *str1, ...)
+{
+    va_list ap;
+    char *rslt;                 /* Output buffer */
+    size_t s;                   /* Total buffer size */
+    size_t n;                   /* Number of arguments */
+    size_t *ltbl;               /* Table of lengths */
+    size_t l, *lp;              /* Length for current argument */
+    const char *p;              /* Currently examined argument */
+    char *q;                    /* Output pointer */
+
+    n = 0;                      /* No strings encountered yet */
+    p = str1;
+    va_start(ap, str1);
+    while (p) {
+        n++;
+        p = va_arg(ap, const char *);
+    }
+    va_end(ap);
+
+    ltbl = nasm_malloc(n * sizeof(size_t));
+
+    s = 1;                      /* Space for final NULL */
+    p = str1;
+    lp = ltbl;
+    va_start(ap, str1);
+    while (p) {
+        *lp++ = l = strlen(p);
+        s += l;
+        p = va_arg(ap, const char *);
+    }
+    va_end(ap);
+
+    q = rslt = nasm_malloc(s);
+
+    p = str1;
+    lp = ltbl;
+    va_start(ap, str1);
+    while (p) {
+        l = *lp++;
+        memcpy(q, p, l);
+        q += l;
+        p = va_arg(ap, const char *);
+    }
+    va_end(ap);
+    *q = '\0';
+
+    nasm_free(ltbl);
+
+    return rslt;
+}