Use perror to output error messages when reading files (#318)

Use wabt_snprintf instead of unsafe sprintf

2 files changed, 13 insertions, 7 deletions

diff --git a/src/binary-writer.cc b/src/binary-writer.cc
index 2117c8e5..172fc9fc 100644
--- a/src/binary-writer.cc
+++ b/src/binary-writer.cc
@@ -626,8 +626,8 @@ static void write_global_header(Context* ctx, const WabtGlobal* global) {
 
 static void write_reloc_section(Context* ctx, RelocSection* reloc_section) {
   char section_name[128];
-  sprintf(section_name, "%s.%s", WABT_BINARY_SECTION_RELOC,
-          reloc_section->name);
+  wabt_snprintf(section_name, sizeof(section_name), "%s.%s",
+                WABT_BINARY_SECTION_RELOC, reloc_section->name);
   begin_custom_section(ctx, section_name, LEB_SECTION_SIZE_GUESS);
   wabt_write_u32_leb128(&ctx->stream, reloc_section->section_code,
                         "reloc section type");
diff --git a/src/common.cc b/src/common.cc
index f2ab97d7..830a17ac 100644
--- a/src/common.cc
+++ b/src/common.cc
@@ -20,10 +20,13 @@
 #include <stdio.h>
 #include <stdint.h>
 #include <string.h>
+#include <limits.h>
 
 #if COMPILER_IS_MSVC
 #include <fcntl.h>
 #include <io.h>
+#include <stdlib.h>
+#define PATH_MAX _MAX_PATH
 #endif
 
 WabtOpcodeInfo g_wabt_opcode_info[WABT_NUM_OPCODES];
@@ -120,29 +123,32 @@ WabtResult wabt_read_file(const char* filename,
                           size_t* out_size) {
   FILE* infile = fopen(filename, "rb");
   if (!infile) {
-    fprintf(stderr, "unable to read file: %s\n", filename);
+    const char* format = "unable to read file %s";
+    char msg[PATH_MAX + sizeof(format)];
+    wabt_snprintf(msg, sizeof(msg), format, filename);
+    perror(msg);
     return WABT_ERROR;
   }
 
   if (fseek(infile, 0, SEEK_END) < 0) {
-    fprintf(stderr, "fseek to end failed.\n");
+    perror("fseek to end failed");
     return WABT_ERROR;
   }
 
   long size = ftell(infile);
   if (size < 0) {
-    fprintf(stderr, "ftell failed.\n");
+    perror("ftell failed");
     return WABT_ERROR;
   }
 
   if (fseek(infile, 0, SEEK_SET) < 0) {
-    fprintf(stderr, "fseek to beginning failed.\n");
+    perror("fseek to beginning failed");
     return WABT_ERROR;
   }
 
   void* data = wabt_alloc(size);
   if (size != 0 && fread(data, size, 1, infile) != 1) {
-    fprintf(stderr, "fread failed.\n");
+    perror("fread failed");
     return WABT_ERROR;
   }