[Accel-config] [PATCH] accel-config: Fix a read buffer length bug

Generic function used to read a string attribute was using a buffer of
max length 64. Attributes like op_cap exceeds that size. Change read
buffer length to 4k. Also removed a redundant memory allocation.

Signed-off-by: Ramesh Thomas <ramesh.thomas(a)intel.com>
---
 accfg/lib/libaccfg.c    | 24 +++++++-----------------
 accfg/libaccel_config.h |  2 +-
 2 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/accfg/lib/libaccfg.c b/accfg/lib/libaccfg.c
index 9cdd8f8..e6c6055 100644
--- a/accfg/lib/libaccfg.c
+++ b/accfg/lib/libaccfg.c
@@ -197,7 +197,7 @@ static int accfg_set_param(struct accfg_ctx *ctx, int dfd, char *name,
 static long accfg_get_param_long(struct accfg_ctx *ctx, int dfd, char *name)
 {
 	int fd = openat(dfd, name, O_RDONLY);
-	char buf[MAX_PARAM_LEN + 1];
+	char buf[MAX_PARAM_LEN];
 	int n;
 	const char *p;
 
@@ -210,7 +210,7 @@ static long accfg_get_param_long(struct accfg_ctx *ctx, int dfd, char *name)
 	if (fd == -1)
 		return -errno;
 
-	n = read(fd, buf, MAX_PARAM_LEN);
+	n = read(fd, buf, MAX_PARAM_LEN - 1);
 	close(fd);
 	if (n <= 0)
 		return -ENXIO;
@@ -226,13 +226,13 @@ static uint64_t accfg_get_param_unsigned_llong(
 		struct accfg_ctx *ctx, int dfd, char *name)
 {
 	int fd = openat(dfd, name, O_RDONLY);
-	char buf[MAX_PARAM_LEN + 1];
+	char buf[MAX_PARAM_LEN];
 	int n;
 
 	if (fd == -1)
 		return -errno;
 
-	n = read(fd, buf, MAX_PARAM_LEN);
+	n = read(fd, buf, MAX_PARAM_LEN - 1);
 	close(fd);
 	if (n <= 0)
 		return -ENXIO;
@@ -247,13 +247,13 @@ static uint64_t accfg_get_param_unsigned_llong(
 static char *accfg_get_param_str(struct accfg_ctx *ctx, int dfd, char *name)
 {
 	int fd = openat(dfd, name, O_RDONLY);
-	char buf[MAX_PARAM_LEN + 1];
+	char buf[MAX_PARAM_LEN];
 	int n;
 
 	if (fd == -1)
 		return NULL;
 
-	n = read(fd, buf, MAX_PARAM_LEN);
+	n = read(fd, buf, MAX_PARAM_LEN - 1);
 	close(fd);
 	if (n <= 0)
 		return NULL;
@@ -618,21 +618,13 @@ static void *add_device(void *parent, int id, const char *ctl_base,
 {
 	struct accfg_ctx *ctx = parent;
 	struct accfg_device *device;
-	char *path;
 	int dfd;
 	int rc;
 	char *p;
 
-	path = calloc(1, strlen(ctl_base) + MAX_PARAM_LEN);
-	if (!path) {
-		err(ctx, "%s: allocation of path failed\n", __func__);
-		return NULL;
-	}
-
 	dfd = open(ctl_base, O_PATH);
 	if (dfd == -1) {
 		err(ctx, "%s open failed: %s\n", __func__, strerror(errno));
-		free(path);
 		return NULL;
 	}
 
@@ -702,7 +694,7 @@ static void *add_device(void *parent, int id, const char *ctl_base,
 	device->mdev_path = p;
 
 	device->device_buf = calloc(1, strlen(device->device_path) +
-			MAX_PARAM_LEN);
+			MAX_BUF_LEN);
 	if (!device->device_buf) {
 		err(ctx, "allocation of device buffer failed\n");
 		goto err_read;
@@ -720,7 +712,6 @@ static void *add_device(void *parent, int id, const char *ctl_base,
 		goto err_dev_path;
 
 	list_add_tail(&ctx->devices, &device->list);
-	free(path);
 
 	return device;
 
@@ -730,7 +721,6 @@ err_read:
 	free(device->mdev_path);
 	free(device);
 err_device:
-	free(path);
 	return NULL;
 }
 
diff --git a/accfg/libaccel_config.h b/accfg/libaccel_config.h
index 8e7a74e..9e952a7 100644
--- a/accfg/libaccel_config.h
+++ b/accfg/libaccel_config.h
@@ -22,7 +22,7 @@ extern "C" {
 
 #define MAX_DEV_LEN 64
 #define MAX_BUF_LEN 128
-#define MAX_PARAM_LEN 64
+#define MAX_PARAM_LEN 4096
 #define TRAFFIC_CLASS_LIMIT 8
 #define WQ_PRIORITY_LIMIT 15
 #define UUID_ZERO "00000000-0000-0000-0000-000000000000"
-- 
2.34.1