From 9140b4b1656e28fd8763ebe53a22a2004feeff1a Mon Sep 17 00:00:00 2001
From: Sebastian <sebastian@sebsite.pw>
Date: Sun, 03 Oct 2021 14:23:41 -0400
Subject: [PATCH] Check for and abort on failed memory allocations

This commit adds checks for memory allocation failures (i.e. malloc or
calloc returns NULL), and cleanly exits the program in such a scenario.
This removes several null-deference bugs.

Signed-off-by: Sebastian <sebastian@sebsite.pw>

---
 include/util.h |  2 ++
 src/main.c     |  6 +++---
 src/string.c   | 17 ++++++-----------
 src/util.c     | 18 ++++++++++++++++++

diff --git a/include/util.h b/include/util.h
index fe50986736a4108788fa34ceee6fb21698bb2292..018bbe64510fc6e304219000c4f115271fb3d357 100644
--- a/include/util.h
+++ b/include/util.h
@@ -25,5 +25,7 @@ uint32_t parser_getch(struct parser *parser);
 void parser_pushch(struct parser *parser, uint32_t ch);
 void parser_pushstr(struct parser *parser, const char *str);
 int roff_macro(struct parser *p, char *cmd, ...);
+void *xcalloc(size_t n, size_t s);
+void *xrealloc(void *p, size_t s);
 
 #endif
diff --git a/src/main.c b/src/main.c
index d90681df2495877ffc19f7ce671a27004e4c5f6c..f11706ab1f17bcaa0952ea0ef1b56013cebfb774 100644
--- a/src/main.c
+++ b/src/main.c
@@ -493,12 +493,12 @@ 		case '\n':
 			goto commit_table;
 		case '|':
 			prevrow = currow;
-			currow = calloc(1, sizeof(struct table_row));
+			currow = xcalloc(1, sizeof(struct table_row));
 			if (prevrow) {
 				// TODO: Verify the number of columns match
 				prevrow->next = currow;
 			}
-			curcell = calloc(1, sizeof(struct table_cell));
+			curcell = xcalloc(1, sizeof(struct table_cell));
 			currow->cell = curcell;
 			column = 0;
 			if (!table) {
@@ -511,7 +511,7 @@ 				parser_fatal(p, "Cannot start a column without "
 						"starting a row first");
 			} else {
 				struct table_cell *prev = curcell;
-				curcell = calloc(1, sizeof(struct table_cell));
+				curcell = xcalloc(1, sizeof(struct table_cell));
 				if (prev) {
 					prev->next = curcell;
 				}
diff --git a/src/string.c b/src/string.c
index 0d1f38f53f8e08c0c89306adf3501c8f7c505fd8..2fbacbe3804c556267bb1feaf6a5d08c58db47be 100644
--- a/src/string.c
+++ b/src/string.c
@@ -2,22 +2,19 @@ #include <stdlib.h>
 #include <stdint.h>
 #include "str.h"
 #include "unicode.h"
+#include "util.h"
 
-static int ensure_capacity(struct str *str, size_t len) {
+static void ensure_capacity(struct str *str, size_t len) {
 	if (len + 1 >= str->size) {
-		char *new = realloc(str->str, str->size * 2);
-		if (!new) {
-			return 0;
-		}
+		char *new = xrealloc(str->str, str->size * 2);
 		str->str = new;
 		str->size *= 2;
 	}
-	return 1;
 }
 
 struct str *str_create() {
-	struct str *str = calloc(1, sizeof(struct str));
-	str->str = malloc(16);
+	struct str *str = xcalloc(1, sizeof(struct str));
+	str->str = xcalloc(16, 1);
 	str->size = 16;
 	str->len = 0;
 	str->str[0] = '\0';
@@ -35,9 +32,7 @@ 	int size = utf8_chsize(ch);
 	if (size <= 0) {
 		return -1;
 	}
-	if (!ensure_capacity(str, str->len + size)) {
-		return -1;
-	}
+	ensure_capacity(str, str->len + size);
 	utf8_encode(&str->str[str->len], ch);
 	str->len += size;
 	str->str[str->len] = '\0';
diff --git a/src/util.c b/src/util.c
index ec55abbe07ca9c08cc0ce7c80034e04729bca31e..15f592895ebc1e085b092e3302482da5c7bf08d2 100644
--- a/src/util.c
+++ b/src/util.c
@@ -69,3 +69,21 @@ 	va_end(ap);
 	fputc('\n', f);
 	return l + 1;
 }
+
+void *xcalloc(size_t n, size_t s) {
+	void *p = calloc(n, s);
+	if (!p) {
+		fputs("Out of memory\n", stderr);
+		abort();
+	}
+	return p;
+}
+
+void *xrealloc(void *p, size_t s) {
+	void *ret = realloc(p, s);
+	if (!ret) {
+		fputs("Out of memory\n", stderr);
+		abort();
+	}
+	return ret;
+}

-- 
2.48.1