feat(userspace/coreutils): add alias command

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Userspace/coreutils/src/alias.c

@@ -0,0 +1,225 @@
+/*
+	This file is part of Fennix Core Utilities.
+
+	Fennix Core Utilities is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Core Utilities is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Core Utilities. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+typedef struct alias_t
+{
+	char *name;
+	char *value;
+	struct alias_t *next;
+} alias_t;
+
+alias_t *aliases = NULL;
+
+void FreeAliases()
+{
+	alias_t *current = aliases;
+	while (current != NULL)
+	{
+		alias_t *next = current->next;
+		free(current->name);
+		free(current->value);
+		free(current);
+		current = next;
+	}
+	aliases = NULL;
+}
+
+alias_t *FindAlias(const char *name)
+{
+	alias_t *current = aliases;
+	while (current != NULL)
+	{
+		if (strcmp(current->name, name) == 0)
+			return current;
+		current = current->next;
+	}
+	return NULL;
+}
+
+void AddAlias(const char *name, const char *value)
+{
+	alias_t *existing = FindAlias(name);
+	if (existing)
+	{
+		free(existing->value);
+		existing->value = strdup(value);
+		return;
+	}
+
+	alias_t *new_alias = malloc(sizeof(alias_t));
+	new_alias->name = strdup(name);
+	new_alias->value = strdup(value);
+	new_alias->next = aliases;
+	aliases = new_alias;
+}
+
+int ReadAliases(const char *filename)
+{
+	FILE *file = fopen(filename, "r");
+	if (!file)
+		return -1;
+
+	char *line = NULL;
+	size_t len = 0;
+	ssize_t read;
+
+	while ((read = getline(&line, &len, file)) != -1)
+	{
+		if (line[read - 1] == '\n')
+			line[read - 1] = '\0';
+
+		char *eq = strchr(line, '=');
+		if (!eq)
+			continue;
+		*eq = '\0';
+
+		AddAlias(line, eq + 1);
+	}
+
+	free(line);
+	fclose(file);
+	return 0;
+}
+
+int WriteAliases(const char *filename)
+{
+	FILE *file = fopen(filename, "w");
+	if (!file)
+	{
+		perror("Error writing aliases");
+		return -1;
+	}
+
+	alias_t *current = aliases;
+	while (current)
+	{
+		fprintf(file, "%s=%s\n", current->name, current->value);
+		current = current->next;
+	}
+
+	fclose(file);
+	return 0;
+}
+
+char *QuoteValue(const char *value)
+{
+	size_t quotes = 0;
+	for (const char *p = value; *p; p++)
+	{
+		if (*p == '\'')
+			quotes++;
+	}
+
+	char *quoted = malloc(strlen(value) + quotes * 4 + 3);
+	if (!quoted)
+		return NULL;
+
+	char *dest = quoted;
+	*dest++ = '\'';
+	for (const char *p = value; *p; p++)
+	{
+		if (*p == '\'')
+		{
+			strcpy(dest, "'\\''");
+			dest += 4;
+		}
+		else
+			*dest++ = *p;
+	}
+	*dest++ = '\'';
+	*dest = '\0';
+	return quoted;
+}
+
+int main(int argc, char *argv[])
+{
+	const char *home = getenv("HOME");
+	if (!home)
+	{
+		fprintf(stderr, "alias: HOME not set\n");
+		return 2;
+	}
+
+	char path[1024];
+	snprintf(path, sizeof(path), "%s/.aliases", home);
+
+	if (ReadAliases(path) == -1 && errno != ENOENT)
+	{
+		perror("Error reading aliases");
+		return 2;
+	}
+
+	int status = 0;
+	if (argc == 1)
+	{
+		alias_t *current = aliases;
+		while (current)
+		{
+			char *q = QuoteValue(current->value);
+			printf("alias %s=%s\n", current->name, q);
+			free(q);
+			current = current->next;
+		}
+	}
+	else
+	{
+		for (int i = 1; i < argc; i++)
+		{
+			char *arg = argv[i];
+			char *eq = strchr(arg, '=');
+
+			if (eq)
+			{
+				*eq = '\0';
+				char *name = arg;
+				char *value = eq + 1;
+				AddAlias(name, value);
+
+				char *q = QuoteValue(value);
+				printf("alias %s=%s\n", name, q);
+				free(q);
+			}
+			else
+			{
+				alias_t *a = FindAlias(arg);
+				if (a)
+				{
+					char *q = QuoteValue(a->value);
+					printf("alias %s=%s\n", a->name, q);
+					free(q);
+				}
+				else
+				{
+					fprintf(stderr, "alias: %s: not found\n", arg);
+					status = 1;
+				}
+			}
+		}
+	}
+
+	if (WriteAliases(path) == -1)
+		status = 1;
+	FreeAliases();
+	return status;
+}