[PATCH] fwts_iasl_interface.c: ensure we read in all of stdout (LP: #1200426)

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Redirecting stdout to a file when running the syntaxcheck test results
in no failures.  We need to ensure we fflush on stdout to flush the
IASL output on stdout down the pipe to the reading parent process.

This patch also ensures we check for NULL on realloc.  Also fixes
an incorrect stdout fd check on pipefds[0] and removes an unnecessary
close on pipefds[1] on the child process.

Took the opportunity to do some white space cleanup and a general tidy
up of the code too.  Must of had a bad day when I originally wrote
this code.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 src/acpica/source/compiler/fwts_iasl_interface.c | 64 +++++++++++++++---------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/src/acpica/source/compiler/fwts_iasl_interface.c b/src/acpica/source/compiler/fwts_iasl_interface.c
index 84670e4..206e0c8 100644
--- a/src/acpica/source/compiler/fwts_iasl_interface.c
+++ b/src/acpica/source/compiler/fwts_iasl_interface.c
@@ -33,7 +33,7 @@ static void init_asl_core(void)
 
 	AcpiDbgLevel = 0;
 
-	for (i=0; i<ASL_NUM_FILES; i++) {
+	for (i = 0; i < ASL_NUM_FILES; i++) {
 		Gbl_Files[i].Handle = NULL;
 		Gbl_Files[i].Filename = NULL;
 	}
@@ -64,8 +64,8 @@ int fwts_iasl_disassemble_aml(const char *aml, const char *outputfile)
 
 		/* Setup ACPICA disassembler globals */
 		Gbl_DisasmFlag = TRUE;
-        	Gbl_DoCompile = FALSE;
-        	Gbl_OutputFilenamePrefix = (char*)outputfile;
+		Gbl_DoCompile = FALSE;
+		Gbl_OutputFilenamePrefix = (char*)outputfile;
 		Gbl_UseDefaultAmlFilename = FALSE;
 
 		/* Throw away noisy errors */
@@ -76,7 +76,7 @@ int fwts_iasl_disassemble_aml(const char *aml, const char *outputfile)
 		break;
 	default:
 		/* Parent */
-		waitpid(pid, &status, WUNTRACED | WCONTINUED);
+		(void)waitpid(pid, &status, WUNTRACED | WCONTINUED);
 	}
 
 	return 0;
@@ -84,13 +84,14 @@ int fwts_iasl_disassemble_aml(const char *aml, const char *outputfile)
 
 int fwts_iasl_assemble_aml(const char *source, char **output)
 {
-	int pipefds[2];
+	int 	pipefds[2];
+	int	status;
+	int 	ret = 0;
+	size_t	len = 0;
+	ssize_t	n;
 	pid_t	pid;
 	char    *data = NULL;
 	char	buffer[8192];
-	int	n;
-	int 	len = 0;
-	int	status;
 
 	if (pipe(pipefds) < 0)
 		return -1;
@@ -98,46 +99,61 @@ int fwts_iasl_assemble_aml(const char *source, char **output)
 	pid = fork();
 	switch (pid) {
 	case -1:
-		close(pipefds[0]);
-		close(pipefds[1]);
+		(void)close(pipefds[0]);
+		(void)close(pipefds[1]);
 		return -1;
 	case 0:
 		/* Child */
 		init_asl_core();
 
-		if (pipefds[0] != STDOUT_FILENO) {
-			dup2(pipefds[1], STDOUT_FILENO);
-			close(pipefds[1]);
+		/* stdout to be redirected down the writer end of pipe */
+		if (pipefds[1] != STDOUT_FILENO) {
+			if (dup2(pipefds[1], STDOUT_FILENO) < 0) {
+				_exit(EXIT_FAILURE);
+			}
 		}
-		close(pipefds[0]);
+		/* Close reader end */
+		(void)close(pipefds[0]);
 
 		/* Setup ACPICA compiler globals */
 		Gbl_DisasmFlag = FALSE;
-        	Gbl_DoCompile = TRUE;
+		Gbl_DoCompile = TRUE;
 		Gbl_PreprocessFlag = TRUE;
-        	Gbl_UseDefaultAmlFilename = FALSE;
-        	Gbl_OutputFilenamePrefix = (char*)source;
+		Gbl_UseDefaultAmlFilename = FALSE;
+		Gbl_OutputFilenamePrefix = (char*)source;
 
-		status = AslDoOnePathname((char*)source, AslDoOneFile);
+		(void)AslDoOnePathname((char*)source, AslDoOneFile);
 
-		close(pipefds[1]);
+		/*
+		 * We need to flush buffered I/O on IASL stdout
+		 * before we exit
+		 */
+		fflush(stdout);
 
 		_exit(0);
 		break;
 	default:
 		/* Parent */
-		close(pipefds[1]);
 
+		/* Close writer end */
+		(void)close(pipefds[1]);
+
+		/* Gather output from IASL */
 		while ((n = read(pipefds[0], buffer, sizeof(buffer))) > 0) {
 			data = realloc(data, len + n + 1);
+			if (data == NULL) {
+				ret = -1;
+				break;
+			}
 			memcpy(data + len, buffer, n);
 			len += n;
-			data[len] = 0;
+			data[len] = '\0';
 		}
-		waitpid(pid, &status, WUNTRACED | WCONTINUED);
-		close(pipefds[0]);
+		(void)waitpid(pid, &status, WUNTRACED | WCONTINUED);
+		(void)close(pipefds[0]);
+		break;
 	}
 
 	*output = data;
-	return 0;
+	return ret;
 }
-- 
1.8.1.2