psh/du: implement 'du' command

Implements tool that estimates file space usage

JIRA: RTOS-745

psh/Makefile

@@ -19,9 +19,9 @@ LOCAL_CFLAGS += -DPSH_SYSEXECWL='"$(PSH_SYSEXECWL)"'
 LOCAL_LDFLAGS := -z stack-size=4096 -z noexecstack
 
 # TODO: search for dirs?
-PSH_ALLCOMMANDS := bind cat cd cp date dd df dmesg echo edit exec hm ifconfig kill \
-ln ls mem mkdir mount nc nslookup ntpclient perf ping pm printenv ps pwd reboot rm \
-rmdir runfile sync sysexec top touch tty umount uptime wget
+PSH_ALLCOMMANDS := bind cat cd cp date dd df du dmesg echo edit exec hm ifconfig \
+kill ln ls mem mkdir mount nc nslookup ntpclient perf ping pm printenv ps pwd reboot \
+rm rmdir runfile sync sysexec top touch tty umount uptime wget
 PSH_COMMANDS ?= $(PSH_ALLCOMMANDS)
 PSH_INTERNAL_APPLETS := pshapp help $(filter $(PSH_ALLCOMMANDS), $(PSH_COMMANDS))
 

psh/du/du.c

@@ -0,0 +1,309 @@
+/*
+ * Phoenix-RTOS
+ *
+ * du - estimates file space usage
+ *
+ * Copyright 2024 Phoenix Systems
+ * Author: Gerard Swiderski
+ *
+ * This file is part of Phoenix-RTOS.
+ *
+ * %LICENSE%
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>   /* memset */
+#include <unistd.h>   /* getopt */
+#include <limits.h>   /* PATH_MAX */
+#include <dirent.h>   /* readdir */
+#include <sys/stat.h> /* lstat */
+
+#include "../psh.h"
+
+#define ALREADY_MAX 64
+#define LEVELS_MAX  64
+
+
+struct already {
+	struct already *next;
+	nlink_t nlink;
+	ino_t inum;
+	int dev;
+};
+
+
+static struct {
+	struct already *already[ALREADY_MAX];
+	char dent[PATH_MAX];
+	/* options */
+	int levels;
+	int8_t ki;
+	bool silent;
+	bool all;
+	bool tot;
+	bool crosschk;
+} du_common;
+
+
+/*
+ * makePath - make the pathname from the directory name, and the directory entry,
+ * placing it in out. If this would overflow return 0, otherwise length of path.
+ */
+static size_t makePath(size_t dlen, const char *f)
+{
+	char *cp = &du_common.dent[dlen];
+	size_t length = strlen(f);
+
+	if ((dlen + length) > (sizeof(du_common.dent) - 2u)) {
+		return 0;
+	}
+
+	if ((dlen != 0u) && (*(cp - 1) != '/')) {
+		*(cp++) = '/';
+	}
+
+	while (length-- != 0u) {
+		*(cp++) = *(f++);
+	}
+	*cp = '\0';
+
+	return cp - du_common.dent;
+}
+
+
+/*
+ * isDone - have we encountered (dev, inum) before? Returns 1 for yes, 0 for no
+ * and remembers (dev, inum, nlink).
+ */
+static int isDone(dev_t dev, ino_t inum, nlink_t nlink)
+{
+	struct already *ap;
+	struct already **pap = &du_common.already[(int)inum % ALREADY_MAX];
+
+	for (;;) {
+		ap = *pap;
+		if (ap == NULL) {
+			break;
+		}
+
+		if ((ap->inum == inum) && (ap->dev == dev)) {
+			ap->nlink--;
+			if (ap->nlink == (nlink_t)0) {
+				*pap = ap->next;
+				free(ap);
+			}
+			return 1;
+		}
+
+		pap = &ap->next;
+	}
+
+	ap = (struct already *)malloc(sizeof(*ap));
+	if (ap == NULL) {
+		fprintf(stderr, "du: Out of memory\n");
+		return -1;
+	}
+
+	ap->next = NULL;
+	ap->inum = inum;
+	ap->dev = dev;
+	ap->nlink = nlink - 1;
+	*pap = ap;
+
+	return 0;
+}
+
+
+static void freeAlreadyList(void)
+{
+	for (int i = 0; i < ALREADY_MAX; ++i) {
+		struct already *list = du_common.already[i];
+		while (list != NULL) {
+			struct already *temp = list;
+			list = list->next;
+			free(temp);
+		}
+	}
+}
+
+
+static size_t roundPrefix(size_t v)
+{
+	switch (du_common.ki) {
+		case 1: return (v + (size_t)999) / (size_t)1000;  /* kilo */
+		case 2: return (v + (size_t)1023) / (size_t)1024; /* Kibi */
+		default: break;
+	}
+	return v;
+}
+
+
+/*
+ * doDirectory - process the directory.
+ * Return the size (in bytes) of the directory and its descendants.
+ */
+static size_t doDirectory(size_t startPos, int curLevel, dev_t dev)
+{
+	DIR *dp;
+	bool maybePrint;
+	struct stat stbuf;
+	size_t total = 0;
+	struct dirent *entry;
+	char *d = du_common.dent;
+
+	if (lstat(d, &stbuf) < 0) {
+		fprintf(stderr, "du: %s: %s\n", d, strerror(errno));
+		return (size_t)0;
+	}
+
+	if ((stbuf.st_dev != dev) && (dev != 0) && (du_common.crosschk)) {
+		return (size_t)0;
+	}
+
+	if (stbuf.st_size > (off_t)0) {
+		total = (size_t)stbuf.st_size;
+	}
+
+	switch (stbuf.st_mode & S_IFMT) {
+		case S_IFDIR:
+			/*
+			 * Directories should not be linked except to "." and "..", so this
+			 * directory should not already have been done.
+			 */
+			maybePrint = !du_common.silent;
+			dp = opendir(d);
+			if (dp == NULL) {
+				break;
+			}
+
+			for (;;) {
+				du_common.dent[startPos] = '\0';
+				entry = readdir(dp);
+				if (entry == NULL) {
+					break;
+				}
+
+				if (!((entry->d_name[0] == '.') && ((entry->d_name[1] == '\0') || ((entry->d_name[1] == '.') && (entry->d_name[2] == '\0'))))) {
+					const size_t nextPos = makePath(startPos, entry->d_name);
+					if (nextPos > 0u) {
+						total += doDirectory(nextPos, curLevel - 1, stbuf.st_dev);
+					}
+				}
+			}
+
+			closedir(dp);
+			break;
+
+		case S_IFBLK:
+		case S_IFCHR:
+			/* st_size for special files is not related to blocks used. */
+			total = (size_t)0;
+			/* fall-through */
+
+		default:
+			if ((stbuf.st_nlink > (nlink_t)1) && (isDone(stbuf.st_dev, stbuf.st_ino, stbuf.st_nlink) != 0)) {
+				return (size_t)0;
+			}
+			maybePrint = du_common.all;
+			break;
+	}
+
+
+	if ((curLevel >= du_common.levels) || ((maybePrint) && (curLevel >= 0))) {
+		printf("%zu\t%s\n", roundPrefix(total), d);
+	}
+
+	return total;
+}
+
+
+static void psh_du_info(void)
+{
+	printf("estimates file space usage");
+}
+
+
+static void psh_du_usage(void)
+{
+	fprintf(stderr, "Usage: du [-acsxkK] [-d depth] [startdir]\n");
+}
+
+
+static int psh_du(int argc, char **argv)
+{
+	int opt;
+	size_t total = 0;
+	const char *startdir = ".";
+
+	memset(&du_common, 0, sizeof(du_common));
+	du_common.levels = LEVELS_MAX;
+
+	for (;;) {
+		opt = getopt(argc, argv, "acsxd:kK");
+		if (opt < 0) {
+			break;
+		}
+
+		switch (opt) {
+			case 'a':
+				du_common.all = 1;
+				break;
+
+			case 'c':
+				du_common.tot = 1;
+				break;
+
+			case 's':
+				du_common.silent = 1;
+				break;
+
+			case 'x':
+				du_common.crosschk = 1;
+				break;
+
+			case 'd':
+				du_common.levels = atoi(optarg);
+				break;
+
+			case 'k':
+				du_common.ki = 1; /* kilo */
+				break;
+
+			case 'K':
+				du_common.ki = 2; /* kibi */
+				break;
+
+			default:
+				psh_du_usage();
+				return EXIT_FAILURE;
+		}
+	}
+
+	do {
+		if (optind < argc) {
+			startdir = argv[optind++];
+		}
+		const size_t startPos = makePath(0, startdir);
+		if (startPos > 0u) {
+			total += doDirectory(startPos, du_common.levels, 0);
+		}
+	} while (optind < argc);
+
+	freeAlreadyList();
+
+	if (du_common.tot) {
+		printf("%zu\ttotal\n", roundPrefix(total));
+	}
+
+	return EXIT_SUCCESS;
+}
+
+
+static void __attribute__((constructor)) du_registerapp(void)
+{
+	static psh_appentry_t app = { .name = "du", .run = psh_du, .info = psh_du_info };
+	psh_registerapp(&app);
+}