Avoid needless dynamic memory allocation

Do not use a dynamically allocated buffer to store the structure
used to pass random bytes to the kernel. The maximum size is
known in advance, so we can use a buffer allocated on the stack.

We can thus get rid of the xmalloc wrapper, which was only used
for that allocation.

lib/Makefile.am

@@ -1,5 +1,5 @@
 noinst_LIBRARIES = libscdrand.a
 
-libscdrand_a_SOURCES = err.compat.h compat.h xmem.c xmem.h
+libscdrand_a_SOURCES = err.compat.h compat.h
 
 libscdrand_a_LIBADD = $(LIBOBJS)

lib/xmem.c

@@ -1,114 +0,0 @@
-/*
- * xmem - Incenp.org Notch Library: die-on-error memory functions
- * Copyright (C) 2011 Damien Goutte-Gattat
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include <xmem.h>
-#include <stdio.h>
-#include <string.h>
-#include <err.h>
-
-void (*xmem_error)(const char *, unsigned int) = NULL;
-
-#define mem_error(f, l)                         \
-    do {                                        \
-        if ( xmem_error )                       \
-            (*xmem_error)((f), (l));            \
-        err(EXIT_FAILURE, "%s, %d", (f), (l));  \
-    } while ( 0 )
-
-void *
-do_malloc(size_t s, const char *file, unsigned int line)
-{
-    void *p;
-
-    if ( ! (p = malloc(s)) && s )
-        mem_error(file, line);
-
-    return p;
-}
-
-void *
-do_calloc(size_t n, size_t s, const char *file, unsigned int line)
-{
-    void *p;
-
-    if ( ! (p = calloc(n, s)) && n && s )
-        mem_error(file, line);
-
-    return p;
-}
-
-void *
-do_realloc(void *p, size_t s, const char *file, unsigned int line)
-{
-    void *np;
-
-    if ( ! (np = realloc(p, s)) && s )
-        mem_error(file, line);
-
-    return np;
-}
-
-char *
-do_strdup(const char *s, const char *file, unsigned int line)
-{
-    char *dup;
-
-    if ( ! (dup = strdup(s)) && s )
-        mem_error(file, line);
-
-    return dup;
-}
-
-int
-do_asprintf(char          **s,
-            const char     *fmt,
-            const char     *file,
-            unsigned int    line,
-            ...)
-{
-    int ret;
-    va_list ap;
-
-    va_start(ap, line);
-    ret = vasprintf(s, fmt, ap);
-    va_end(ap);
-
-    if ( ret == -1 )
-        mem_error(file, line);
-
-    return ret;
-}
-
-int
-do_vasprintf(char         **s,
-             const char    *fmt,
-             const char    *file,
-             unsigned int   line,
-             va_list        ap)
-{
-    int ret;
-
-    if ( (ret = vasprintf(s, fmt, ap)) == -1 )
-        mem_error(file, line);
-
-    return ret;
-}

lib/xmem.h

@@ -1,60 +0,0 @@
-/*
- * xmem - Incenp.org Notch Library: die-on-error memory functions
- * Copyright (C) 2011 Damien Goutte-Gattat
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef ICP20110203_XMEM_H
-#define ICP20110203_XMEM_H
-
-#include <stdlib.h>
-#include <stdarg.h>
-
-#ifdef __cpluscplus
-extern "C" {
-#endif
-
-extern void (*xmem_error)(const char *, unsigned int);
-
-void *
-do_malloc(size_t, const char *, unsigned int);
-
-void *
-do_calloc(size_t, size_t, const char *, unsigned int);
-
-void *
-do_realloc(void *, size_t, const char *, unsigned int);
-
-char *
-do_strdup(const char *, const char *, unsigned int);
-
-int
-do_asprintf(char **, const char *, const char *, unsigned int, ...);
-
-int
-do_vasprintf(char **, const char *, const char *, unsigned int, va_list);
-
-#define xmalloc(s)          do_malloc(s,       __FILE__, __LINE__)
-#define xcalloc(n,s)        do_calloc(n, s,    __FILE__, __LINE__)
-#define xrealloc(p,s)       do_realloc(p, s,   __FILE__, __LINE__)
-#define xstrdup(s)          do_strdup(s,       __FILE__, __LINE__)
-#define xasprintf(s,f,...)  do_asprintf(s, f,  __FILE__, __LINE__, __VA_ARGS__)
-#define xvasprintf(s,f,v)   do_vasprintf(s, f, __FILE__, __LINE__, v)
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* !ICP20110203_XMEM_H */

src/scdrand.c

@@ -37,7 +37,6 @@
 
 #include <gcrypt.h>
 
-#include "xmem.h"
 #include "gpg-util.h"
 
 #define MAX_RANDOM_BYTES        256
@@ -206,18 +205,19 @@ start_privileged_process(unsigned factor)
 
     if ( (pid = fork()) == 0 ) {
         int random_fd, n;
-        char buffer[MAX_RANDOM_BYTES];
+        char buffer[sizeof(struct rand_pool_info) + MAX_RANDOM_BYTES], *ptr;
         struct rand_pool_info *rpi;
 
+        rpi = (struct rand_pool_info *)buffer;
+        ptr = (char *) &(rpi->buf[0]);
+
         close(fd[1]);
 
         if ( (random_fd = open("/dev/random", O_RDONLY)) == -1 )
             err(EXIT_FAILURE, "Cannot open /dev/random");
 
-        rpi = xmalloc(sizeof(struct rand_pool_info) + MAX_RANDOM_BYTES);
-
         while ( 1 ) {
-            n = read(fd[0], buffer, sizeof(buffer));
+            n = read(fd[0], ptr, MAX_RANDOM_BYTES);
 
             if ( n == -1 )
                 err(EXIT_FAILURE, "Cannot read from pipe");
@@ -227,7 +227,6 @@ start_privileged_process(unsigned factor)
 
             rpi->entropy_count = n * factor;
             rpi->buf_size = n;
-            memcpy(&(rpi->buf[0]), buffer, n);
 
             if ( ioctl(random_fd, RNDADDENTROPY, rpi) == -1 )
                 warn("Cannot add entropy");