dlt_common: Execute system command using execvp

Add function dlt_execute_command() to execute system command using
execvp.

Signed-off-by: KHANH LUONG HONG DUY <khanh.luonghongduy@vn.bosch.com>

2 files changed, 63 insertions, 0 deletions

diff --git a/include/dlt/dlt_common.h b/include/dlt/dlt_common.h
index 71b9c10..aa10796 100644
--- a/include/dlt/dlt_common.h
+++ b/include/dlt/dlt_common.h
@@ -1618,6 +1618,14 @@ void dlt_getloginfo_conv_ascii_to_id(char *rp, int *rp_count, char *wp, int len)
  */
 void dlt_hex_ascii_to_binary(const char *ptr, uint8_t *binary, int *size);
 
+/**
+ * Helper function to execute the execvp function in a new child process.
+ * @param filename file path to store the stdout of command (NULL if not required)
+ * @param command execution command followed by arguments with NULL-termination
+ * @return negative value if there was an error
+ */
+int dlt_execute_command(char *filename, char *command, ...);
+
 #   ifdef __cplusplus
 }
 #   endif
diff --git a/src/shared/dlt_common.c b/src/shared/dlt_common.c
index d545fe0..bc4d5e5 100644
--- a/src/shared/dlt_common.c
+++ b/src/shared/dlt_common.c
@@ -32,9 +32,11 @@
 #include <limits.h>   /* for NAME_MAX */
 #include <inttypes.h> /* for PRI formatting macro */
 #include <stdarg.h>
+#include <err.h>
 
 #include <errno.h>
 #include <sys/stat.h> /* for mkdir() */
+#include <sys/wait.h>
 
 #include "dlt_user_shared.h"
 #include "dlt_common.h"
@@ -4063,3 +4065,56 @@ DltReturnValue dlt_file_quick_parsing(DltFile *file, const char *filename,
     fclose(output);
     return ret;
 }
+
+
+int dlt_execute_command(char *filename, char *command, ...){
+    va_list val;
+    int argc;
+    char ** args = NULL;
+    int ret = 0;
+
+    if (command == NULL)
+        return -1;
+
+    /* Determine number of variadic arguments */
+    va_start(val, command);
+    for (argc = 2; va_arg(val, char *) != NULL;  argc++);
+    va_end(val);
+
+    /* Allocate args, put references to command */
+    args = (char **) malloc(argc * sizeof(char*));
+    args[0] = command;
+
+    va_start(val, command);
+    for (int i = 0; args[i] != NULL; i++)
+        args[i+1] = va_arg(val, char *);
+    va_end(val);
+
+    /* Run command in child process */
+    pid_t pid = fork();
+    if (pid == 0) { /* child process */
+
+        /* Redirect output if required */
+        if (filename != NULL) {
+            int fd = open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+            if (fd < 0)
+                err(-1, "%s failed on open()", __func__);
+
+            if (dup2(fd, STDOUT_FILENO) == -1) {
+                close(fd);
+                err(-1, "%s failed on dup2()", __func__);
+            }
+            close(fd);
+        }
+
+        /* Run command */
+        execvp(command, (char **)args);
+    }
+    else if (pid == -1) /* error in fork */
+        ret = -1;
+    else /* parent */
+        wait(&ret);
+
+    free(args);
+    return ret;
+}