Squash commits for public release

libs/libc/stdlib/env.c

@@ -0,0 +1,115 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void free_var(const char* string)
+{
+    // TODO: Implement me!
+}
+
+char* getenv(const char* name)
+{
+    size_t len = strlen(name);
+    for (int i = 0; environ[i]; i++) {
+        const char* envv = environ[i];
+        char* eqpos = strchr(envv, '=');
+        if (!eqpos) {
+            continue;
+        }
+        size_t curlen = (size_t)(eqpos - envv);
+        if (curlen == len && strncmp(name, envv, len) == 0) {
+            return (char*)&envv[len + 1];
+        }
+    }
+
+    return NULL;
+}
+
+int setenv(const char* name, const char* value, int overwrite)
+{
+    if (!overwrite && getenv(name)) {
+        return 0;
+    }
+
+    int name_len = strlen(name);
+    int value_len = strlen(value);
+    int len = name_len + 1 + value_len;
+    char* string = (char*)malloc(len + 1);
+    strncpy(string, name, name_len);
+    string[name_len] = '=';
+    strncpy(&string[name_len + 1], value, value_len);
+    string[len] = '\0';
+    return putenv(string);
+}
+
+int putenv(char* string)
+{
+    char* pos = strchr(string, '=');
+    if (!pos) {
+        return unsetenv(string);
+    }
+
+    size_t len = (size_t)(pos - string);
+    int env_i = 0;
+    for (; environ[env_i]; env_i++) {
+        const char* envv = environ[env_i];
+        char* eqpos = strchr(envv, '=');
+        if (!eqpos) {
+            continue;
+        }
+        size_t curlen = (size_t)(eqpos - envv);
+        if (len != curlen) {
+            continue;
+        }
+
+        if (strncmp(string, envv, len) == 0) {
+            free_var(envv);
+            environ[env_i] = string;
+            return 0;
+        }
+    }
+
+    char** new_environ = (char**)malloc(sizeof(char*) * (env_i + 2));
+    for (int i = 0; i < env_i; i++) {
+        new_environ[i] = environ[i];
+    }
+    new_environ[env_i] = string;
+    new_environ[env_i + 1] = NULL;
+
+    extern int __environ_malloced;
+    if (__environ_malloced) {
+        free(environ);
+    }
+    environ = new_environ;
+    __environ_malloced = 1;
+    return 0;
+}
+
+int unsetenv(const char* name)
+{
+    size_t len = strlen(name);
+    int env_i = 0;
+    int remove_pos = 0;
+    const char* remove_env = NULL;
+    for (; environ[env_i]; env_i++) {
+        const char* envv = environ[env_i];
+        char* eqpos = strchr(envv, '=');
+        if (!eqpos) {
+            continue;
+        }
+        size_t curlen = (size_t)(eqpos - envv);
+        if (len != curlen) {
+            continue;
+        }
+
+        if (strncmp(name, envv, len) == 0) {
+            remove_pos = env_i;
+            remove_env = envv;
+        }
+    }
+
+    size_t move_len = ((env_i - 1) - remove_pos) * sizeof(char*);
+    memmove(&environ[remove_pos], &environ[remove_pos + 1], move_len);
+    free_var(remove_env);
+    return 0;
+}