Read fru header into struct and check for errors

Author: aneeshdurg

fru_reader.c

@@ -4,28 +4,42 @@
 #include "fru_reader.h"
 #include "fatal.h"
 
-void safe_read(int fd, void *buffer, size_t length) {
+static void safe_read(int fd, void *buffer, size_t length) {
 	size_t total_bytes_read = 0;
 	while (total_bytes_read != length) {
 		ssize_t bytes_read = read(
 			fd, buffer + total_bytes_read, length - total_bytes_read);
 		if (bytes_read == -1)
 			fatal("Error reading file");
+		if (bytes_read == 0)
+			fatal("Reached end of file");
 
 		total_bytes_read += bytes_read;
 	}
 }
 
+fru_t *read_fru_header(int fd) {
+	fru_t *fru = malloc(sizeof(fru_t));
+	if (!fru)
+		return NULL;
+	safe_read(fd, fru, sizeof(fru_t));
+	return fru;
+}
+
 /**
  * Allocate and read a fru_chassis_area_t from a file descriptor
  */
 fru_chassis_area_t *read_fru_chassis_area(int fd) {
 	size_t base_len = sizeof(fru_chassis_area_t);
 	fru_chassis_area_t *area = malloc(base_len);
+	if (!area)
+		return NULL;
 	safe_read(fd, area, base_len);
 	size_t data_len = 8 * area->blocks;
-	area = realloc(area, base_len + data_len);
-	safe_read(fd, &area->data, data_len);
+	area = realloc(area, data_len);
+	if (!area)
+		return NULL;
+	safe_read(fd, &area->data, data_len - base_len);
 
 	return area;
 }
@@ -36,10 +50,14 @@ fru_chassis_area_t *read_fru_chassis_area(int fd) {
 fru_board_area_t *read_fru_board_area(int fd) {
 	size_t base_len = sizeof(fru_board_area_t);
 	fru_board_area_t *area = malloc(base_len);
+	if (!area)
+		return NULL;
 	safe_read(fd, area, base_len);
 	size_t data_len = 8 * area->blocks;
-	area = realloc(area, base_len + data_len);
-	safe_read(fd, &area->data, data_len);
+	area = realloc(area, data_len);
+	if (!area)
+		return NULL;
+	safe_read(fd, &area->data, data_len - base_len);
 
 	return area;
 }
@@ -50,10 +68,14 @@ fru_board_area_t *read_fru_board_area(int fd) {
 fru_product_area_t *read_fru_product_area(int fd) {
 	size_t base_len = sizeof(fru_product_area_t);
 	fru_product_area_t *area = malloc(base_len);
+	if (!area)
+		return NULL;
 	safe_read(fd, area, base_len);
 	size_t data_len = 8 * area->blocks;
-	area = realloc(area, base_len + data_len);
-	safe_read(fd, &area->data, data_len);
+	area = realloc(area, data_len);
+	if (!area)
+		return NULL;
+	safe_read(fd, &area->data, data_len - base_len);
 
 	return area;
 }

fru_reader.h

@@ -1,4 +1,5 @@
 #include "fru.h"
+fru_t *read_fru_header(int fd);
 fru_chassis_area_t *read_fru_chassis_area(int fd);
 fru_board_area_t *read_fru_board_area(int fd);
 fru_product_area_t *read_fru_product_area(int fd);

frugen.c

@@ -476,57 +476,53 @@ int main(int argc, char *argv[])
 						fatal("Failed to open file: %s", strerror(errno));
 					}
 
-					char common_header[8];
-					safe_read(fd, common_header, 8);
-
-					// Common Header Format Version = common_header[0]
-					// Internal Use Area Starting Offset = common_header[1]
-					uint16_t chassis_start_offset = 8 * common_header[2];
-					uint16_t board_start_offset = 8 * common_header[3];
-					uint16_t product_start_offset = 8 * common_header[4];
-					// MultiRecord Area Starting Offset = 8 * common_header[5]
-					// Padding = common_header[6] = 0
-					// Checksum = common_header[7]
-
-					// For the above offsets, an offset of 0 is valid and implies
-					// that the field is not present.
-
-					bool data_has_chassis = chassis_start_offset != 0;
-					bool data_has_board = board_start_offset != 0;
-					bool data_has_product = product_start_offset != 0;
-
-					if (data_has_chassis) {
-                        lseek(fd, chassis_start_offset, SEEK_SET);
-                        fru_chassis_area_t *chassis_raw =
-                            read_fru_chassis_area(fd);
-                        bool success = fru_decode_chassis_info(
-                            chassis_raw, &chassis);
-                        if (!success)
-                            fatal("Failed to decode chassis!");
-                        free(chassis_raw);
-
+					fru_t *raw_fru = read_fru_header(fd);
+					if (!raw_fru)
+						fatal("Failed to read fru header");
+
+					if (raw_fru->chassis != 0) {
+						if (lseek(fd, 8 * raw_fru->chassis, SEEK_SET) < 0)
+							fatal("Failed to seek");
+
+						fru_chassis_area_t *chassis_raw =
+							read_fru_chassis_area(fd);
+						bool success = fru_decode_chassis_info(
+							chassis_raw, &chassis);
+						if (!success)
+							fatal("Failed to decode chassis");
+
+						free(chassis_raw);
 						has_chassis = true;
 					}
-					if (data_has_board) {
-						lseek(fd, board_start_offset, SEEK_SET);
+					if (raw_fru->board != 0) {
+						if(lseek(fd, 8 * raw_fru->board, SEEK_SET) < 0)
+							fatal("Failed to seek");
 
 						fru_board_area_t *board_raw = read_fru_board_area(fd);
 						bool success = fru_decode_board_info(board_raw, &board);
+						if (!success)
+							fatal("Failed to decode board");
 
+						free(board_raw);
 						has_board = true;
 						has_bdate = true;
 					}
-					if (data_has_product) {
-						lseek(fd, product_start_offset, SEEK_SET);
+					if (raw_fru->product != 0) {
+						if (lseek(fd, 8 * raw_fru->product, SEEK_SET) < 0)
+							fatal("Failed to seek");
 
 						fru_product_area_t *product_raw =
 							read_fru_product_area(fd);
 						bool success =
 							fru_decode_product_info(product_raw, &product);
+						if (!success)
+							fatal("Failed to decode product");
 
+						free(product_raw);
 						has_product = true;
 					}
 
+					free(raw_fru);
 					close(fd);
 				}
 				else {