Add primitive config file parsing support

[log-plotter] / config.c

diff --git a/config.c b/config.c
new file mode 100644 (file)
index 0000000..54f672e
--- /dev/null
+++ b/config.c
@@ -0,0 +1,135 @@
+#include <stdio.h>
+#include <glob.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "config.h"
+#include "trace.h"
+
+static int parse_config_line(char *line, char **variable, char **value)
+{
+#define SKIP_UNTIL(_str, _cond)                \
+       while (*_str && (_cond))        \
+               _str++;
+
+       SKIP_UNTIL(line, isspace(*line));
+
+       /* Skip comments */
+       if (*line == '#')
+               return -1;
+
+       /* The actual variable name begins here */
+       *variable = line;
+
+       /* Find where the variable name ends */
+       SKIP_UNTIL(line, !isspace(*line) && *line != '=');
+
+       if (*line == '=') {
+               *line = '\0';
+               line++;
+               goto value_start;
+       }
+
+       /* If we encounter line end already, the line can't be valid */
+       if (!*line)
+               return -1;
+
+       /* Terminate the variable name */
+       *line = '\0';
+       line++;
+        
+       /* Find the equal sign */
+       SKIP_UNTIL(line, *line != '=');
+
+       if (*line != '=')
+               return -1;
+       line++;
+
+       SKIP_UNTIL(line, isspace(*line));
+
+value_start:
+       *value = line;
+
+       SKIP_UNTIL(line, *line != '\n' && *line != '#');
+       *line = 0;
+
+       return 0;
+}
+
+static int store_variable_value_to_plotter_config(const char *variable,
+                                               const char *value,
+                                               struct plotter_config *cfg)
+{
+#define TEST_STR_STORE_STR_RETURN(_cfg, _variable, _str, _value)       \
+       if (!strcmp(_variable, #_str) && !cfg->_str) {                  \
+               cfg->_str = strdup(_value);                             \
+               return 0;                                               \
+       }
+
+#define TEST_STR_STORE_INT_RETURN(_cfg, _variable, _str, _value)       \
+       if (!strcmp(_variable, #_str)) {                                \
+               cfg->_str = atoi(_value);                               \
+               return 0;                                               \
+       }
+
+       TEST_STR_STORE_STR_RETURN(cfg, variable, charger_name, value);
+       TEST_STR_STORE_STR_RETURN(cfg, variable, plotter_scripts_dir, value);
+       TEST_STR_STORE_STR_RETURN(cfg, variable, images_output_dir, value);
+       TEST_STR_STORE_STR_RETURN(cfg, variable, device_path, value);
+       TEST_STR_STORE_STR_RETURN(cfg, variable, log_path, value);
+       TEST_STR_STORE_INT_RETURN(cfg, variable, baudrate, value);
+
+       return -1;
+}
+
+static int read_config_file(FILE *file, struct plotter_config *cfg)
+{
+       char line[1024];
+       char *variable, *value;
+
+       while (fgets(line, sizeof(line), file)) {
+               if (parse_config_line(line, &variable, &value))
+                       continue;
+
+               if (!store_variable_value_to_plotter_config(variable, value,
+                                                               cfg))
+                       continue;
+
+               pr_debug("Discarding unsupported config variable %s\n",
+                       variable);
+       }
+
+       return 0;
+}
+
+int populate_config_data_from_file(const char *path,
+                               struct plotter_config *cfg)
+{
+       glob_t globbuf;
+       FILE *file;
+       int ret;
+
+       ret = glob(path, GLOB_TILDE, NULL, &globbuf);
+       if (ret)
+               return -1;
+
+       if (globbuf.gl_pathc == 0) {
+               pr_debug("No config file foud from path %s\n", path);
+               return -1;
+       }
+
+       if (globbuf.gl_pathc > 1) {
+               pr_warn("Found multiple config files from path %s, using the first one\n",
+                       path);
+       }
+
+       file = fopen(globbuf.gl_pathv[0], "r");
+       if (!file) {
+               pr_err("Failed to open config file %s: %m\n",
+                       globbuf.gl_pathv[0]);
+               return -1;
+       }
+
+       return read_config_file(file, cfg);
+}