Set errno in alloc functions and add further tests

src/header/stdlib/mod.rs

@@ -78,11 +78,15 @@ pub extern "C" fn abs(i: c_int) -> c_int {
 
 #[no_mangle]
 pub unsafe extern "C" fn aligned_alloc(alignment: size_t, size: size_t) -> *mut c_void {
-    if size % alignment != 0 {
-        return ptr::null_mut();
+    if size % alignment == 0 {
+        /* The size-is-multiple-of-alignment requirement is the only
+         * difference between aligned_alloc() and memalign(). */
+        memalign(alignment, size)
+    }
+    else {
+        platform::errno = errno::EINVAL;
+        ptr::null_mut()
     }
-
-    memalign(alignment, size)
 }
 
 #[no_mangle]
@@ -190,13 +194,19 @@ pub unsafe extern "C" fn calloc(nelem: size_t, elsize: size_t) -> *mut c_void {
     let size_result = nelem.checked_mul(elsize);
     match size_result {
         Some(size) => {
+            /* If allocation fails here, errno setting will be handled
+             * by malloc() */
             let ptr = malloc(size);
             if !ptr.is_null() {
                 intrinsics::write_bytes(ptr as *mut u8, 0, size);
             }
             ptr
+        },
+        None => {
+            // For overflowing multiplication, we have to set errno here
+            platform::errno = errno::ENOMEM;
+            ptr::null_mut()
         }
-        None => core::ptr::null_mut(),
     }
 }
 
@@ -403,12 +413,29 @@ pub extern "C" fn lrand48() -> c_long {
 
 #[no_mangle]
 pub unsafe extern "C" fn malloc(size: size_t) -> *mut c_void {
-    platform::alloc(size)
+    let ptr = platform::alloc(size);
+    if ptr.is_null() {
+        platform::errno = errno::ENOMEM;
+    }
+    ptr
 }
 
 #[no_mangle]
 pub unsafe extern "C" fn memalign(alignment: size_t, size: size_t) -> *mut c_void {
-    platform::alloc_align(size, alignment)
+    /* Check if alignment is a (positive) power of two. The second
+     * expression will never underflow, due to Rust's lazy boolean
+     * operators. */
+    if alignment > 0 && (alignment & (alignment - 1)) == 0 {
+        let ptr = platform::alloc_align(size, alignment);
+        if ptr.is_null() {
+            platform::errno = errno::ENOMEM;
+        }
+        ptr
+    }
+    else {
+        platform::errno = errno::EINVAL;
+        ptr::null_mut()
+    }
 }
 
 #[no_mangle]
@@ -613,7 +640,11 @@ pub extern "C" fn random() -> c_long {
 
 #[no_mangle]
 pub unsafe extern "C" fn realloc(ptr: *mut c_void, size: size_t) -> *mut c_void {
-    platform::realloc(ptr, size)
+    let ptr = platform::realloc(ptr, size);
+    if ptr.is_null() {
+        platform::errno = errno::ENOMEM;
+    }
+    ptr
 }
 
 #[no_mangle]

tests/stdlib/alloc.c

@@ -1,34 +1,129 @@
 #include <malloc.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stddef.h> /* for size_t */
 #include <stdint.h> /* for SIZE_MAX */
 
 #include "test_helpers.h"
 
 int main(void) {
-    char * ptr = (char *)malloc(256);
-    printf("malloc %p\n", ptr);
+    size_t sample_alloc_size = 256;
+    size_t sample_realloc_size = sample_alloc_size + 1;
+    
+    /* ensure values are mapped to variables */
+    size_t max_size = SIZE_MAX;
+    size_t aligned_alloc_alignment = 128;
+    size_t aligned_alloc_goodsize = 256;
+    size_t aligned_alloc_badsize = 257;
+    
     int i;
-    for(i = 0; i < 256; i++) {
-        ptr[i] = (char)i;
+    
+    errno = 0;
+    char * ptr_malloc = (char *)malloc(sample_alloc_size);
+    int malloc_errno = errno;
+    printf("malloc                : %p, errno: %d = %s\n",
+        ptr_malloc, malloc_errno, strerror(malloc_errno));
+    for(i = 0; i < sample_alloc_size; i++) {
+        ptr_malloc[i] = (char)i;
     }
-    free(ptr);
-
-    char * ptrc = (char *)calloc(256, 1);
-    printf("calloc %p\n", ptrc);
-    for(i = 0; i < 256; i++) {
-        ptrc[i] = (char)i;
+    free(ptr_malloc);
+    
+    errno = 0;
+    char * ptr_malloc_maxsize = (char *)malloc(max_size);
+    int malloc_maxsize_errno = errno;
+    printf("malloc (SIZE_MAX)     : %p, errno: %d = %s\n",
+        ptr_malloc_maxsize, malloc_maxsize_errno,
+        strerror(malloc_maxsize_errno));
+    free(ptr_malloc_maxsize);
+    
+    errno = 0;
+    char * ptr_calloc = (char *)calloc(sample_alloc_size, 1);
+    int calloc_errno = errno;
+    printf("calloc                : %p, errno: %d = %s\n", ptr_calloc,
+        calloc_errno, strerror(calloc_errno));
+    for(i = 0; i < sample_alloc_size; i++) {
+        ptr_calloc[i] = (char)i;
     }
-    free(ptrc);
-
-    char * ptrco = (char *)calloc(SIZE_MAX, SIZE_MAX);
-    printf("calloc (overflowing) %p\n", ptrco);
-    free(ptrco); /* clean up correctly even if overflow is not handled */
-
-    char * ptra = (char *)memalign(256, 256);
-    printf("memalign %p\n", ptra);
-    for(i = 0; i < 256; i++) {
-        ptra[i] = (char)i;
+    free(ptr_calloc);
+    
+    errno = 0;
+    char * ptr_calloc_overflow = (char *)calloc(max_size, max_size);
+    int calloc_overflow_errno = errno;
+    printf("calloc (overflowing)  : %p, errno: %d = %s\n",
+        ptr_calloc_overflow, calloc_overflow_errno,
+        strerror(calloc_overflow_errno));
+    free(ptr_calloc_overflow); /* clean up correctly even if overflow is not handled */
+    
+    char * ptr_realloc = (char *)malloc(sample_alloc_size);
+    errno = 0;
+    ptr_realloc = (char *)realloc(ptr_realloc, sample_realloc_size);
+    int realloc_errno = errno;
+    printf("realloc               : %p, errno: %d = %s\n",
+        ptr_realloc, realloc_errno, strerror(realloc_errno));
+    for(i = 0; i < sample_realloc_size; i++) {
+        ptr_realloc[i] = (char)i;
+    }
+    free(ptr_realloc);
+    
+    char * ptr_realloc_maxsize = (char *)malloc(sample_alloc_size);
+    errno = 0;
+    ptr_realloc_maxsize = (char *)realloc(ptr_realloc_maxsize, max_size);
+    int realloc_maxsize_errno = errno;
+    printf("realloc (SIZE_MAX)    : %p, errno: %d = %s\n",
+        ptr_realloc_maxsize, realloc_maxsize_errno,
+        strerror(realloc_maxsize_errno));
+    free(ptr_realloc_maxsize);
+    
+    errno = 0;
+    char * ptr_memalign = (char *)memalign(256, sample_alloc_size);
+    int memalign_errno = errno;
+    printf("memalign              : %p, errno: %d = %s\n", ptr_memalign,
+        memalign_errno, strerror(memalign_errno));
+    for(i = 0; i < sample_alloc_size; i++) {
+        ptr_memalign[i] = (char)i;
     }
-    free(ptra);
+    free(ptr_memalign);
+    
+    errno = 0;
+    char * ptr_memalign_maxsize = (char *)memalign(256, max_size);
+    int memalign_maxsize_errno = errno;
+    printf("memalign (SIZE_MAX)   : %p, errno: %d = %s\n",
+        ptr_memalign_maxsize, memalign_maxsize_errno,
+        strerror(memalign_maxsize_errno));
+    free(ptr_memalign_maxsize);
+    
+    errno = 0;
+    char * ptr_memalign_align0 = (char *)memalign(0, sample_alloc_size);
+    int memalign_align0_errno = errno;
+    printf("memalign (alignment 0): %p, errno: %d = %s\n",
+        ptr_memalign_align0, memalign_align0_errno,
+        strerror(memalign_align0_errno));
+    free(ptr_memalign_align0);
+    
+    errno = 0;
+    char * ptr_memalign_align3 = (char *)memalign(3, sample_alloc_size);
+    int memalign_align3_errno = errno;
+    printf("memalign (alignment 3): %p, errno: %d = %s\n",
+        ptr_memalign_align3, memalign_align3_errno,
+        strerror(memalign_align3_errno));
+    free(ptr_memalign_align3);
+    
+    errno = 0;
+    char * ptr_aligned_alloc_goodsize = (char *)aligned_alloc(aligned_alloc_alignment, aligned_alloc_goodsize);
+    int aligned_alloc_goodsize_errno = errno;
+    printf("aligned_alloc (size %% alignment == 0):\n");
+    printf("                        %p, errno: %d = %s\n",
+        ptr_aligned_alloc_goodsize, aligned_alloc_goodsize_errno,
+        strerror(aligned_alloc_goodsize_errno));
+    free(ptr_aligned_alloc_goodsize);
+    
+    errno = 0;
+    char * ptr_aligned_alloc_badsize = (char *)aligned_alloc(aligned_alloc_alignment, aligned_alloc_badsize);
+    int aligned_alloc_badsize_errno = errno;
+    printf("aligned_alloc (size %% alignment != 0):\n");
+    printf("                        %p, errno: %d = %s\n",
+        ptr_aligned_alloc_badsize, aligned_alloc_badsize_errno,
+        strerror(aligned_alloc_badsize_errno));
+    free(ptr_aligned_alloc_badsize);
 }