semihosting: add semihosting_basedir command

This command allows users to set base working directory for the
semihosting I/O operations.Default is the current OpenOCD directory.

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: I80c5979e4c96d66cccdd12cc6fcd5f353e5c6b4d
Reviewed-on: https://review.openocd.org/c/openocd/+/6888
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

doc/openocd.texi

@@ -9624,6 +9624,12 @@ is valid during the run of the event handlers and is accessible with this
 command.
 @end deffn
 
+@deffn {Command} {arm semihosting_basedir} [dir]
+@cindex ARM semihosting
+Set the base directory for semihosting I/O, either an absolute path or a path relative to OpenOCD working directory.
+Use "." for the current directory.
+@end deffn
+
 @section ARMv4 and ARMv5 Architecture
 @cindex ARMv4
 @cindex ARMv5

src/target/semihosting_common.c

@@ -159,6 +159,7 @@ int semihosting_common_init(struct target *target, void *setup,
 	semihosting->result = -1;
 	semihosting->sys_errno = -1;
 	semihosting->cmdline = NULL;
+	semihosting->basedir = NULL;
 
 	/* If possible, update it in setup(). */
 	semihosting->setup_time = clock();
@@ -870,17 +871,21 @@ int semihosting_common(struct target *target)
 					semihosting->sys_errno = EINVAL;
 					break;
 				}
-				uint8_t *fn = malloc(len+1);
+				size_t basedir_len = semihosting->basedir ? strlen(semihosting->basedir) : 0;
+				uint8_t *fn = malloc(basedir_len + len + 2);
 				if (!fn) {
 					semihosting->result = -1;
 					semihosting->sys_errno = ENOMEM;
 				} else {
-					retval = target_read_memory(target, addr, 1, len, fn);
+					strncpy((char *)fn, semihosting->basedir, basedir_len);
+					if (fn[basedir_len - 1] != '/')
+						fn[basedir_len++] = '/';
+					retval = target_read_memory(target, addr, 1, len, fn + basedir_len);
 					if (retval != ERROR_OK) {
 						free(fn);
 						return retval;
 					}
-					fn[len] = 0;
+					fn[basedir_len + len] = 0;
 					/* TODO: implement the :semihosting-features special file.
 					 * */
 					if (semihosting->is_fileio) {
@@ -2025,6 +2030,44 @@ COMMAND_HANDLER(handle_common_semihosting_read_user_param_command)
 	return ERROR_OK;
 }
 
+COMMAND_HANDLER(handle_common_semihosting_basedir_command)
+{
+	struct target *target = get_current_target(CMD_CTX);
+
+	if (CMD_ARGC > 1)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	if (!target) {
+		LOG_ERROR("No target selected");
+		return ERROR_FAIL;
+	}
+
+	struct semihosting *semihosting = target->semihosting;
+	if (!semihosting) {
+		command_print(CMD, "semihosting not supported for current target");
+		return ERROR_FAIL;
+	}
+
+	if (!semihosting->is_active) {
+		command_print(CMD, "semihosting not yet enabled for current target");
+		return ERROR_FAIL;
+	}
+
+	if (CMD_ARGC > 0) {
+		free(semihosting->basedir);
+		semihosting->basedir = strdup(CMD_ARGV[0]);
+		if (!semihosting->basedir) {
+			command_print(CMD, "semihosting failed to allocate memory for basedir!");
+			return ERROR_FAIL;
+		}
+	}
+
+	command_print(CMD, "semihosting base dir: %s",
+		semihosting->basedir ? semihosting->basedir : "");
+
+	return ERROR_OK;
+}
+
 const struct command_registration semihosting_common_handlers[] = {
 	{
 		.name = "semihosting",
@@ -2068,5 +2111,12 @@ const struct command_registration semihosting_common_handlers[] = {
 		.usage = "",
 		.help = "read parameters in semihosting-user-cmd-0x10X callbacks",
 	},
+	{
+		.name = "semihosting_basedir",
+		.handler = handle_common_semihosting_basedir_command,
+		.mode = COMMAND_EXEC,
+		.usage = "[dir]",
+		.help = "set the base directory for semihosting I/O operations",
+	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/semihosting_common.h

@@ -176,6 +176,9 @@ struct semihosting {
 	/** The current time when 'execution starts' */
 	clock_t setup_time;
 
+	/** Base directory for semihosting I/O operations. */
+	char *basedir;
+
 	int (*setup)(struct target *target, int enable);
 	int (*post_result)(struct target *target);
 };

src/target/target.c

@@ -57,6 +57,7 @@
 #include "transport/transport.h"
 #include "arm_cti.h"
 #include "smp.h"
+#include "semihosting_common.h"
 
 /* default halt wait timeout (ms) */
 #define DEFAULT_HALT_TIMEOUT 5000
@@ -2258,6 +2259,8 @@ static void target_destroy(struct target *target)
 	if (target->type->deinit_target)
 		target->type->deinit_target(target);
 
+	if (target->semihosting)
+		free(target->semihosting->basedir);
 	free(target->semihosting);
 
 	jtag_unregister_event_callback(jtag_enable_callback, target);