utils-std

commit: 5ebd5d747ab67436708a92e87cbe1b2b42411c6f
parent 37883f2036135bd68cebd5ed1d31d3c4b834f88c
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Tue, 12 Mar 2024 00:56:50 +0100

cmd/chmod: new

Diffstat:
M
Makefile
4
++++
A
cmd/chmod.c
170
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 174 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -76,3 +76,7 @@ test-lib/strtodur: test-lib/strtodur.c lib/strtodur.c Makefile
 cmd/df: cmd/df.c lib/humanize.c Makefile
 	rm -f ${<:=.gcov} ${@:=.gcda} ${@:=.gcno}
 	$(CC) -std=c99 $(CFLAGS) -o $@ cmd/df.c lib/humanize.c $(LDFLAGS) $(LDSTATIC)
+
+cmd/chmod: cmd/chmod.c lib/mode.c Makefile
+	rm -f ${<:=.gcov} ${@:=.gcda} ${@:=.gcno}
+	$(CC) -std=c99 $(CFLAGS) -o $@ cmd/chmod.c lib/mode.c $(LDFLAGS) $(LDSTATIC)
diff --git a/cmd/chmod.c b/cmd/chmod.c
@@ -0,0 +1,170 @@
+// utils-std: Collection of commonly available Unix tools
+// SPDX-FileCopyrightText: 2017-2022 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
+// SPDX-License-Identifier: MPL-2.0
+
+#define _POSIX_C_SOURCE 200809L
+
+#include "../lib/mode.h"
+
+#include <dirent.h> // fdopendir, readdir, closedir
+#include <errno.h>
+#include <fcntl.h>  // AT_FDCWD
+#include <limits.h> // PATH_MAX
+#include <stdbool.h>
+#include <stdio.h>    // fprintf
+#include <string.h>   // strerror
+#include <sys/stat.h> // chmod, fstatat, S_ISDIR
+#include <unistd.h>   // getopt
+
+static int
+do_fchmodat(int fd, char *fdname, char *mode_arg, char *path, bool recursive)
+{
+	struct stat stats;
+	int err = 0;
+
+	if(fstatat(fd, path, &stats, AT_SYMLINK_NOFOLLOW) != 0)
+	{
+		fprintf(
+		    stderr, "chmod: Failed getting status for '%s/%s': %s\n", fdname, path, strerror(errno));
+		return 1;
+	}
+
+	const char *errstr = NULL;
+	mode_t mode        = new_mode(mode_arg, stats.st_mode, &errstr);
+	if(errstr != NULL)
+	{
+		fprintf(stderr, "chmod: Failed parsing '%s': %s\n", mode_arg, errstr);
+		return 1;
+	}
+
+	if(fchmodat(fd, path, mode, 0) != 0)
+	{
+		fprintf(stderr,
+		        "chmod: Failed setting permissions to 0%6o for '%s/%s': %s\n",
+		        mode,
+		        fdname,
+		        path,
+		        strerror(errno));
+		return 1;
+	}
+
+	if(recursive && S_ISDIR(stats.st_mode))
+	{
+		int dir = openat(fd, path, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+		if(dir == -1)
+		{
+			fprintf(
+			    stderr, "chmod: Couldn't open '%s/%s' as directory: %s\n", fdname, path, strerror(errno));
+			return 1;
+		}
+
+		DIR *dirp = fdopendir(dir);
+		if(dirp == NULL)
+		{
+			fprintf(stderr, "chmod: Couldn't get DIR entry for opened '%s/%s': %s\n", fdname, path, strerror(errno));
+			return 1;
+		}
+
+		while(true)
+		{
+			struct dirent *dp = readdir(dirp);
+			if(dp == NULL)
+			{
+				if(errno == 0) break;
+
+				fprintf(stderr, "chmod: Failed reading directory '%s/%s': %s\n", fdname, path, strerror(errno));
+				closedir(dirp);
+				return 1;
+			}
+
+			if(strcmp(dp->d_name, ".") == 0) continue;
+			if(strcmp(dp->d_name, "..") == 0) continue;
+
+			char destdir[PATH_MAX] = "";
+			if(snprintf(destdir, PATH_MAX, "%s/%s", fdname, path) < 0)
+			{
+				fprintf(stderr, "chmod: Couldn't concatenate '%s' into parent '%s', skipping to next entry: %s", fdname, path, strerror(errno));
+				err++;
+				continue;
+			}
+
+			// No depth counter for now, unlikely to be a problem
+			int ret = do_fchmodat(dir, destdir, mode_arg, dp->d_name, true);
+			if(ret != 0) return ret;
+		}
+
+		// fdopendir allocates memory for DIR, needs closedir
+		if(closedir(dirp) != 0)
+		{
+			fprintf(stderr, "chmod: Deallocating directory entry for '%s/%s' failed: %s\n", fdname, path, strerror(errno));
+			return 1;
+		}
+	}
+
+	return err;
+}
+
+static void
+usage()
+{
+	fprintf(stderr, "Usage: chmod [-R] <mode> <file ...>\n");
+}
+
+int
+main(int argc, char *argv[])
+{
+	bool opt_R = false;
+	int c      = -1;
+
+	while((c = getopt(argc, argv, ":R")) != -1)
+	{
+		switch(c)
+		{
+		case 'R':
+			opt_R = true;
+			break;
+		case ':':
+			fprintf(stderr, "chmod: Error: Missing operand for option: '-%c'\n", optopt);
+			usage();
+			return 1;
+		case '?':
+			switch(optopt)
+			{
+			case 'r':
+			case 'w':
+			case 'x':
+			case 'u':
+			case 'g':
+			case 'o':
+			case 'a':
+				fprintf(stderr,
+				        "chmod: Portability Warning: Pass -- before a mode with a leading dash(-) to "
+				        "separate it from options");
+				optind--;
+				goto getopt_out;
+
+			default:
+				fprintf(stderr, "chmod: Error: Unrecognised option: '-%c'\n", optopt);
+				usage();
+				return 1;
+			}
+		}
+	}
+getopt_out:
+
+	argc -= optind;
+	argv += optind;
+
+	if(argc < 2)
+	{
+		fprintf(stderr, "chmod: Expects >=2 arguments, %d given\n", argc);
+		usage();
+		return 1;
+	}
+
+	for(int i = 1; i < argc; i++)
+	{
+		int ret = do_fchmodat(AT_FDCWD, ".", argv[0], argv[i], opt_R);
+		if(ret != 0) return ret;
+	}
+}