From 2f4cc13cdde6bd79356513085fc85d97ebd7c76a Mon Sep 17 00:00:00 2001
From: Charles Cabergs <me@cacharle.xyz>
Date: Sun, 9 Aug 2020 19:29:02 +0200
Subject: Added chown [WIP]

---
 chown.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 193 insertions(+)
 create mode 100644 chown.c

(limited to 'chown.c')

diff --git a/chown.c b/chown.c
new file mode 100644
index 0000000..d273afd
--- /dev/null
+++ b/chown.c
@@ -0,0 +1,193 @@
+#define _POSIX_C_SOURCE 200809L
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdarg.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <limits.h>
+#include <dirent.h>
+#include <errno.h>
+#include <ctype.h>
+
+typedef enum
+{
+	RMODE_FOLLOW_ROOT,
+	RMODE_FOLLOW_ALL,
+	RMODE_NO_FOLLOW,
+}	t_recursive_mode;
+
+typedef enum
+{
+	VLEVEL_CHANGE,
+	VLEVEL_QUIET,
+	VLEVEL_VERBOSE,
+}	t_verbose_level;
+
+static t_verbose_level  g_verbosity      = VLEVEL_QUIET;
+static bool             g_follow_link    = true;
+static bool             g_recursive      = false;
+static t_recursive_mode g_recursive_mode = RMODE_NO_FOLLOW;
+static char             *g_name          = "chown";
+static uid_t            g_user_id        = -1;
+static gid_t            g_group_id       = -1;
+
+void	verror_log(const char *format, va_list ap)
+{
+	fprintf(stderr, "%s: ", g_name);
+	vfprintf(stderr, format, ap);
+	fputc('\n', stderr);
+}
+
+void	error_log(const char *format, ...)
+{
+	va_list	ap;
+
+	va_start(ap, format);
+	verror_log(format, ap);
+	va_end(ap);
+}
+
+void	fatal(const char *format, ...)
+{
+	va_list	ap;
+
+	va_start(ap, format);
+	verror_log(format, ap);
+	va_end(ap);
+	exit(EXIT_FAILURE);
+}
+
+bool parse_id(char *id_str, id_t *id_ptr, bool group)
+{
+	char *end;
+
+	if (isdigit(*id_str))
+	{
+		errno = 0;
+		long tmp = strtol(id_str, &end, 10);
+		if (errno != 0 || tmp > UINT_MAX || *end != '\0')
+			return false;
+		*id_ptr = (id_t)tmp;
+	}
+	else
+	{
+		struct passwd *pw = getpwnam(id_str);
+		if (pw == NULL)
+			return false;
+		if (group)
+			*id_ptr = pw->pw_gid;
+		else
+			*id_ptr = pw->pw_uid;
+	}
+	return true;
+}
+
+bool file_chown(char *path, bool root)
+{
+	char		recursive_path[PATH_MAX + 1] = {'\0'};
+	struct stat	statbuf;
+
+
+	if (stat(path, &statbuf) == -1)
+	{
+		error_log("cannot access '%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	errno = 0;
+	if ((!g_recursive && g_follow_link)
+		|| (g_recursive && (g_recursive_mode == RMODE_FOLLOW_ALL
+			|| (root && g_recursive_mode == RMODE_FOLLOW_ROOT))))
+		chown(path, g_user_id, g_group_id);
+	else
+		lchown(path, g_user_id, g_group_id);
+	if (errno != 0)
+	{
+		error_log("changing ownership of '%s': %s", path, strerror(errno));
+		return false;
+	}
+
+	if (g_recursive)
+	{
+		errno = 0;
+		DIR *directory = opendir(path);
+
+		if (directory == NULL && errno == ENOTDIR)
+			return true;
+		if (directory == NULL)
+		{
+			error_log("cannot access '%s': %s", path, strerror(errno));
+			return false;
+		}
+
+		strcpy(recursive_path, path);
+		if (path[strlen(path) - 1] != '/')
+			strcat(recursive_path, "/");
+
+		struct dirent *entry;
+		while ((entry = readdir(directory)) != NULL)
+		{
+			if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+				continue;
+			strcat(recursive_path, entry->d_name);
+			file_chown(recursive_path, false);
+			strrchr(recursive_path, '/')[1] = '\0';
+		}
+		closedir(directory);
+	}
+	return true;
+}
+
+/*
+**
+** TODO
+** don't change group/user if not asked
+** change group to login group is trailling : after user in cmd
+**
+*/
+
+int main(int argc, char **argv)
+{
+	int option;
+
+	while ((option = getopt(argc, argv, "cfvhRHLP")) != -1)
+	{
+		switch (option)
+		{
+			case 'c': g_verbosity      = VLEVEL_CHANGE;     break;
+			case 'f': g_verbosity      = VLEVEL_QUIET;      break;
+			case 'v': g_verbosity      = VLEVEL_VERBOSE;    break;
+			case 'h': g_follow_link    = false;             break;
+			case 'R': g_recursive      = true;              break;
+			case 'H': g_recursive_mode = RMODE_FOLLOW_ROOT; break;
+			case 'L': g_recursive_mode = RMODE_FOLLOW_ALL;  break;
+			case 'P': g_recursive_mode = RMODE_NO_FOLLOW;   break;
+		}
+	}
+
+	if (argc - optind == 0)
+		fatal("missing operand");
+	if (argc - optind == 1)
+		fatal("missing operand after '%s'", argv[optind]);
+
+	char *user_str = argv[optind];
+	char *group_str = strchr(argv[optind], ':');
+	if (group_str != NULL)
+	{
+		*group_str = '\0';
+		group_str++;
+	}
+
+	if (!parse_id(user_str, &g_user_id, false))
+		fatal("invalid user '%s'", user_str);
+	if (group_str != NULL && !parse_id(group_str, &g_group_id, true))
+		fatal("invalid group '%s:%s'", user_str, group_str);
+
+	for (optind++; optind < argc; optind++)
+		file_chown(argv[optind], true);
+
+	return EXIT_SUCCESS;
+}
-- 
cgit