From 3a4dd7dd423023b35d501bdad966f13e18703cef Mon Sep 17 00:00:00 2001
From: pankunull <panku_null@proton.me>
Date: Sat, 30 Aug 2025 20:15:59 +0200
Subject: The program got out of hand, I'm doing stuff it doesn't need. Good
 exercise!

---
 Makefile     |  16 +++
 src/chproc.c | 322 ++++++++++++++++++++++++++++++++++++++++++++---------------
 2 files changed, 255 insertions(+), 83 deletions(-)

diff --git a/Makefile b/Makefile
index af3c7f7..23a3caa 100644
--- a/Makefile
+++ b/Makefile
@@ -6,6 +6,10 @@ CFLAGS = -Wall -O2
 SRC_DIR = src
 BIN_DIR = bin
 
+# Installation directory
+PREFIX ?= /usr/local
+BINDIR ?= $(PREFIX)/bin
+
 # Source and target names
 TARGET = chproc
 SRC = $(SRC_DIR)/$(TARGET).c
@@ -57,6 +61,18 @@ define run_test
 	fi
 endef
 
+# Install
+install: $(BIN)
+	@echo "Installing $(TARGET) to $(BINDIR)"
+	mkdir -p $(BINDIR)
+	cp -v $(BIN) $(BINDIR)/
+
+# Uninstall
+uninstall:
+	@echo "Removing $(TARGET) from $(BINDIR)"
+	rm -v -f $(BINDIR)/$(TARGET)
+
+# Test
 test: $(BIN)
 	$(call run_test,$(TARGET),no args)
 	$(call run_test,$(TARGET),$(ARG))
diff --git a/src/chproc.c b/src/chproc.c
index 46876a5..b4ebee9 100644
--- a/src/chproc.c
+++ b/src/chproc.c
@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * chproc.c - simple process checker
+ * chproc.c - simple process manager
  *
- * Iterate over /proc and print PIDs of processes matching the given name.
+ * Features: list and kill.
  */
 
 #include <stdio.h>
@@ -20,52 +20,96 @@
 #include <stdbool.h>
 
 #define PROGRAM_NAME "chproc"
+#define PROGRAM_VERSION "0.1"
 
-struct options {
-	int list;
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+#define DIR_PROC "/proc"
+
+
+struct flag_options {
+	int name;
 	int all;
 	int kill;
+	int help;
+	int version;
+};
+
+
+struct data_options {
 	char *process_name;
 	char *process_pid;
 };
 
 
-static void options_init(struct options *x)
-{
-	x->list = false;
-	x->all	= false;
-	x->kill = false;
-	x->process_pid = NULL;
-	x->process_name = NULL;
-}
+struct options {
+	struct flag_options flags;
+	struct data_options data;
+};
+
+
+struct flag_handler {
+	int *flag;
+	int id;
+};
 
 
-static void usage(void)
+enum flag_index {
+	F_NAME,
+	F_ALL,
+	F_KILL,
+	F_HELP,
+	F_VERSION
+};
+
+
+static int usage(void)
 {
 	fprintf(stderr,
 		"Usage: %s <option> [process_name, pid]\n"
-		" -l, --list <name>	list all pid for that process\n"
+		" -n, --name <name>	list all pid for that process\n"
 		" -a, --all		list all processes\n"
-		" -k, --kill <PID>	kill a proces give then PID\n"
+		" -k, --kill <PID>	kill a process give then PID\n"
+		" -h, --help		show this help\n"
+		" -v, --version		show version\n"
 		, PROGRAM_NAME);
+
+	return 2;
 }
 
 
+struct process_info {
+	pid_t pid;
+	char name[256];
+};
 
-static int process_list(DIR *dir,
-		const char *proc_name,
-		struct options *x)
+
+struct process_info *get_process_list(size_t *count)
 {
+	DIR *dir;
+	struct dirent *entry;
+	struct process_info *list;
+	size_t capacity;
+	size_t n;
+	long pid;
 	char path[PATH_MAX];
+	FILE *f;
 	char buffer[256];
 	char *endptr;
-	FILE *f;
-	int count;
-	long pid;
-	struct dirent *entry;
 	size_t len;
+	struct process_info *tmp;
+
+	dir = opendir(DIR_PROC);
+
+	capacity = 128;
+	n = 0;
+	list = malloc(capacity * (sizeof(*list)));
+
+	if (!list) {
+		closedir(dir);
+		return NULL;
+	}
 
-	count = 0;
 
 	while ((entry = readdir(dir)) != NULL) {
 		/* skip "." and ".." */
@@ -74,21 +118,17 @@ static int process_list(DIR *dir,
 		if (strcmp(entry->d_name, "..") == 0)
 			continue;
 
-
 		pid = strtol(entry->d_name, &endptr, 10);
 
-		if (*endptr != '\0') /* not a pure number */
+		/* not a pure number */
+		if (*endptr != '\0')
 			continue;
 
 		snprintf(path, sizeof(path), "/proc/%ld/comm", pid);
-
 		f = fopen(path, "r");
 
-		if (!f) {
-			fprintf(stderr, "Failed to open %s: %s\n",
-				path, strerror(errno));
+		if (!f)
 			continue;
-		}
 
 		if (!(fgets(buffer, sizeof(buffer), f)))
 			continue;
@@ -98,39 +138,83 @@ static int process_list(DIR *dir,
 		if (len > 0 && buffer[len-1] == '\n')
 			buffer[len-1] = '\0';
 
-		/* flag instead of re-writing a function */
-		if (x->list) {
-			if (strcmp(buffer, proc_name) == 0) {
-				printf("%s - %s\n", entry->d_name, buffer);
-				++count;
+		list[n].pid = (pid_t)pid;
+		strncpy(list[n].name, buffer, sizeof(list[n].name));
+		list[n].name[sizeof(list[n].name) - 1] = '\0';
+		n++;
+
+		/* Resize array if needed */
+		if (n >= capacity) {
+			capacity *= 2;
+			tmp = realloc(list, capacity * sizeof(*list));
+
+			if (!tmp) {
+				free(list);
+				fclose(f);
+				closedir(dir);
+				return NULL;
 			}
-		} else {
-			printf("%s - %s\n", entry->d_name, buffer);
-			++count;
+			list = tmp;
 		}
+
+
 		fclose(f);
 	}
 
 	closedir(dir);
 
-	if (count == 0)
-		return 1;
-	else
-		return 0;
+	*count = n;
+	return list;
 }
 
 
-static int process_kill(const char *process_id)
+static int process_get_all(struct process_info *list,
+			size_t count)
+{
+	size_t i;
+
+	for (i = 0; i < count; i++) {
+		printf("%d - %s\n",
+			list[i].pid, list[i].name);
+	}
+
+	return 0;
+}
+
+
+static int process_get_name(char *pname,
+				struct options *x,
+				struct process_info *list,
+				size_t count)
+{
+	char *proc_name;
+	size_t i;
+
+	proc_name = pname;
+
+
+	for (i = 0; i < count; i++) {
+		if (x->flags.name && strcmp(list[i].name, proc_name) == 0) {
+			printf("%d - %s\n", list[i].pid, list[i].name);
+			++count;
+		}
+	}
+	return 0;
+}
+
+
+static int process_get_kill(const char *process_id)
 {
 	pid_t pid;
 
-	if (atoi(process_id) < 1) {
+	pid = (pid_t) atoi(process_id);
+
+	if (pid < 1) {
 		fprintf(stderr, "'%s': not a pid or valid job\n", process_id);
 		usage();
 		return 1;
 	}
 
-	pid = (pid_t) atoi(process_id);
 
 	if (kill(pid, SIGTERM) == -1) {
 		perror("kill failed");
@@ -142,66 +226,138 @@ static int process_kill(const char *process_id)
 }
 
 
-int main(int argc, char *argv[])
+int proc_check(void)
+{
+	DIR *dir;
+
+	/* /proc/ must exist */
+	dir = opendir(DIR_PROC);
+
+	if (dir == NULL) {
+		fprintf(stderr, "/proc/ not found.\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+
+int parse_args(int argc, char *argv[],
+		struct options *x)
 {
 	int opt;
-	DIR *dir_proc;
 
-	struct options x;
+	memset(x, 0, sizeof(*x));
 
 	struct option long_options[] = {
-		{"list", required_argument, 0, 'l'},
-		{"all", no_argument, 0, 'a'},
-		{"kill", required_argument, 0, 'k'},
+		{"name",	required_argument,	0, 'n'},
+		{"all",		no_argument,		0, 'a'},
+		{"kill",	required_argument,	0, 'k'},
+		{"help",	no_argument,		0, 'h'},
+		{"version",	no_argument,		0, 'v'},
 		{0, 0, 0, 0}
 	};
 
-	options_init(&x);
 
-	/* /proc/ must to exist */
-	dir_proc = opendir("/proc");
-	if (dir_proc == NULL) {
-		fprintf(stderr, "/proc/ not found.\n");
-		return EXIT_FAILURE;
+	if (argc < 2)
+		return 2;
+
+	while ((opt = getopt_long(argc,
+				argv, "n:ak:",
+				long_options, NULL)) != -1) {
+		switch (opt) {
+		case 'n':
+			x->flags.name = true;
+			x->data.process_name = optarg;
+		break;
+		case 'a':
+			x->flags.all = true;
+		break;
+		case 'k':
+			x->flags.kill = true;
+			x->data.process_pid = optarg;
+		break;
+		case 'h':
+			x->flags.help = true;
+		break;
+		case 'v':
+			x->flags.version = true;
+		break;
+		default:
+			return 2;
+		}
 	}
 
-	if (argc < 2) {
+	return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+	struct options x = {0};
+	int ret;
+	size_t count;
+	struct process_info *procs;
+	struct flag_handler handlers[] = {
+		{ &x.flags.name, F_NAME },
+		{ &x.flags.all, F_ALL },
+		{ &x.flags.kill, F_KILL },
+		{ &x.flags.help, F_HELP },
+		{ &x.flags.version, F_VERSION },
+	};
+	size_t i;
+	size_t n_flags;
+
+	ret = parse_args(argc, argv, &x);
+
+	if (proc_check() != 0)
+		return 1;
+
+	if (ret != 0) {
 		usage();
-		return 2;
+		return ret;
 	}
 
-	while ((opt = getopt_long(argc, argv, "l:k:a",
-		long_options, NULL)) != -1) {
-		switch (opt) {
-		case 'l':
-			x.list = true;
-			x.process_name = optarg;
+	procs = get_process_list(&count);
+
+	if (!procs) {
+		fprintf(stderr, "Failed to read process list\n");
+		return 1;
+	}
+
+
+	n_flags = ARRAY_SIZE(handlers);
+
+	for (i = 0; i < n_flags; i++) {
+		if (*(handlers[i].flag)) {
+			switch (handlers[i].id) {
+			case F_NAME:
+				if (process_get_name(x.data.process_name,
+						&x, procs, count) == 1)
+					return 1;
 			break;
-		case 'a':
-			x.all = true;
+			case F_ALL:
+				if (process_get_all(procs, count) == 1)
+					return 1;
 			break;
-		case 'k':
-			x.kill = true;
-			x.process_pid = optarg;
+			case F_KILL:
+				if (process_get_kill(x.data.process_pid) == 1)
+					return 1;
 			break;
-		default:
-			fprintf(stderr,
-				"Unknow option.\n");
-			usage();
-			exit(2);
+			case F_HELP:
+				usage();
+				return 2;
+			case F_VERSION:
+				printf("%s: %s\n", PROGRAM_NAME,
+						PROGRAM_VERSION);
+				return 0;
+			}
 		}
 	}
 
-	if (x.list || x.all)
-		if (process_list(dir_proc, x.process_name, &x) == 1)
-			return 1;
 
-	if (x.kill)
-		if (process_kill(x.process_pid) == 1)
-			return 1;
+	free(procs);
 
 	return 0;
 }
 
-
-
-- 
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