config: add a new ‘environment’ section

This section allows the user to define custom environment variables to
be set in the child process:

  [environment]
  name=value

config.c

@@ -2200,6 +2200,29 @@ err:
     return false;
 }
 
+static bool
+parse_section_environment(struct context *ctx)
+{
+    struct config *conf = ctx->conf;
+    const char *key = ctx->key;
+    const char *value = ctx->value;
+
+    tll_foreach(conf->env_vars, it) {
+        if (strcmp(it->item.name, key) == 0) {
+            free(it->item.value);
+            it->item.value = xstrdup(value);
+            return true;
+        }
+    }
+
+    struct env_var var = {
+        .name = xstrdup(key),
+        .value = xstrdup(value),
+    };
+    tll_push_back(conf->env_vars, var);
+    return true;
+}
+
 static bool
 parse_section_tweak(struct context *ctx)
 {
@@ -2403,6 +2426,7 @@ enum section {
     SECTION_URL_BINDINGS,
     SECTION_MOUSE_BINDINGS,
     SECTION_TEXT_BINDINGS,
+    SECTION_ENVIRONMENT,
     SECTION_TWEAK,
     SECTION_COUNT,
 };
@@ -2427,6 +2451,7 @@ static const struct {
     [SECTION_URL_BINDINGS] =    {&parse_section_url_bindings, "url-bindings"},
     [SECTION_MOUSE_BINDINGS] =  {&parse_section_mouse_bindings, "mouse-bindings"},
     [SECTION_TEXT_BINDINGS] =   {&parse_section_text_bindings, "text-bindings"},
+    [SECTION_ENVIRONMENT] =     {&parse_section_environment, "environment"},
     [SECTION_TWEAK] =           {&parse_section_tweak, "tweak"},
 };
 
@@ -2867,6 +2892,7 @@ config_load(struct config *conf, const char *conf_path,
             .sixel = true,
         },
 
+        .env_vars = tll_init(),
         .notifications = tll_init(),
     };
 
@@ -3147,6 +3173,14 @@ config_clone(const struct config *old)
     key_binding_list_clone(&conf->bindings.url, &old->bindings.url);
     key_binding_list_clone(&conf->bindings.mouse, &old->bindings.mouse);
 
+    tll_foreach(old->env_vars, it) {
+        struct env_var copy = {
+            .name = xstrdup(it->item.name),
+            .value = xstrdup(it->item.value),
+        };
+        tll_push_back(conf->env_vars, copy);
+    }
+
     conf->notifications.length = 0;
     conf->notifications.head = conf->notifications.tail = 0;
     tll_foreach(old->notifications, it) {
@@ -3207,6 +3241,12 @@ config_free(struct config *conf)
     free_key_binding_list(&conf->bindings.url);
     free_key_binding_list(&conf->bindings.mouse);
 
+    tll_foreach(conf->env_vars, it) {
+        free(it->item.name);
+        free(it->item.value);
+        tll_remove(conf->env_vars, it);
+    }
+
     user_notifications_free(&conf->notifications);
 }
 

config.h

@@ -104,6 +104,12 @@ struct config_spawn_template {
     struct argv argv;
 };
 
+struct env_var {
+    char *name;
+    char *value;
+};
+typedef tll(struct env_var) env_var_list_t;
+
 struct config {
     char *term;
     char *shell;
@@ -296,6 +302,8 @@ struct config {
     struct config_spawn_template notify;
     bool notify_focus_inhibit;
 
+    env_var_list_t env_vars;
+
     struct {
         enum fcft_scaling_filter fcft_filter;
         bool overflowing_glyphs;

foot.ini

@@ -33,6 +33,9 @@
 # selection-target=primary
 # workers=<number of logical CPUs>
 
+[environment]
+# name=value
+
 [bell]
 # urgent=no
 # notify=no

slave.c

@@ -305,8 +305,9 @@ err:
 
 pid_t
 slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
-            char *const *envp, const char *term_env, const char *conf_shell,
+            char *const *envp, const env_var_list_t *extra_env_vars,
-            bool login_shell, const user_notifications_t *notifications)
+            const char *term_env, const char *conf_shell, bool login_shell,
+            const user_notifications_t *notifications)
 {
     int fork_pipe[2];
     if (pipe2(fork_pipe, O_CLOEXEC) < 0) {
@@ -356,6 +357,11 @@ slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
         setenv("TERMINFO", FOOT_TERMINFO_PATH, 1);
 #endif
 
+        if (extra_env_vars != NULL) {
+            tll_foreach(*extra_env_vars, it)
+                setenv(it->item.name, it->item.value, 1);
+        }
+
         char **_shell_argv = NULL;
         char **shell_argv = NULL;
 

slave.h

@@ -3,9 +3,11 @@
 
 #include <sys/types.h>
 
+#include "config.h"
 #include "user-notification.h"
 
 pid_t slave_spawn(
     int ptmx, int argc, const char *cwd, char *const *argv, char *const *envp,
-    const char *term_env, const char *conf_shell, bool login_shell,
+    const env_var_list_t *extra_env_vars, const char *term_env,
+    const char *conf_shell, bool login_shell,
     const user_notifications_t *notifications);

terminal.c

@@ -1248,7 +1248,7 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
 
     /* Start the slave/client */
     if ((term->slave = slave_spawn(
-             term->ptmx, argc, term->cwd, argv, envp,
+             term->ptmx, argc, term->cwd, argv, envp, &conf->env_vars,
              conf->term, conf->shell, conf->login_shell,
              &conf->notifications)) == -1)
     {