Reformat code

.clang-format

@@ -0,0 +1,16 @@
+BasedOnStyle: LLVM
+IndentWidth: 8
+TabWidth: 8
+UseTab: Always
+BreakBeforeBraces: Linux
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: InlineOnly
+ColumnLimit: 80
+AlignConsecutiveDeclarations: false
+AlignConsecutiveAssignments: false
+AlignEscapedNewlines: Left
+AlignOperands: false
+IndentCaseLabels: false
+SpaceBeforeParens: ControlStatements
+

README.md

@@ -9,6 +9,7 @@ Welcome! This is a collection of chapter summaries from the book **Linux System
 - [Chapter 3 – Buffered I/O](chp3/README.md)
 - [Chapter 4 – Advanced File I/O](chp4/README.md)
 - [Chapter 5 - Process Management](chp5/README.md)
+- [Chapter 6 - Advanced Process Management](chp6/README.md)
 - [Exercises](exercises/README.md)
 
 > Each file contains an English summary of the chapter's key concepts.

chp1/syscalls/example1.c

@@ -2,7 +2,8 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	int fd = open("test.txt", O_CREAT | O_RDWR);
 	// close(fd);
 	return EXIT_SUCCESS;

chp2/fopenflags.c

@@ -1,7 +1,7 @@
-#include <stdio.h>
-#include <fcntl.h>
-#include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
 
 int main(void)
 {

chp2/fopenmode.c

@@ -1,12 +1,13 @@
-#include <stdio.h>
-#include <fcntl.h>
-#include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
 
 int main(void)
 {
 	int fd;
-	fd = open("test.txt", O_CREAT | O_EXCL, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
+	fd = open("test.txt", O_CREAT | O_EXCL,
+		  S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
 	if (fd == -1)
 		perror("open");
 	close(fd);

chp2/fpread.c

@@ -6,7 +6,8 @@
 #define _XOPEN_SOURCE 500
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	printf("Try to open file read.txt\n");
 	int fd = open("read.txt", O_RDONLY);
 	if (fd == -1) {
@@ -22,7 +23,8 @@ int main(void) {
 		return -1;
 	}
 
-  // cannot rewind cursor at the start file because pread use "bytes_read_total" for position
+	// cannot rewind cursor at the start file because pread use
+	// "bytes_read_total" for position
 
 	printf("File size of %d bytes\n", len);
 
@@ -32,9 +34,12 @@ int main(void) {
 
 	size_t bytes_read_total = 0;
 	ssize_t ret;
-  while (bytes_read_total < len && (ret = pread(fd, buf, len - bytes_read_total, bytes_read_total)) != -1) {
+	while (bytes_read_total < len &&
+	       (ret = pread(fd, buf, len - bytes_read_total,
+			    bytes_read_total)) != -1) {
 		if (ret == -1) {
-      if (errno == EINTR) continue;
+			if (errno == EINTR)
+				continue;
 			perror("Failed to read read.txt");
 			break;
 		}

chp2/fread.c

@@ -5,7 +5,8 @@
 #include <string.h>
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	printf("Try to open file read.txt\n");
 	int fd = open("read.txt", O_RDONLY);
 	if (fd == -1) {
@@ -31,9 +32,12 @@ int main(void) {
 
 	size_t bytes_read_total = 0;
 	ssize_t ret;
-  while (bytes_read_total < len && (ret = read(fd, buf + bytes_read_total, len - bytes_read_total)) != 0) {
+	while (bytes_read_total < len &&
+	       (ret = read(fd, buf + bytes_read_total,
+			   len - bytes_read_total)) != 0) {
 		if (ret == -1) {
-      if (errno == EINTR) continue;
+			if (errno == EINTR)
+				continue;
 			perror("Failed to read read.txt");
 			break;
 		}

chp2/ftruncate.c

@@ -1,7 +1,8 @@
-#include <unistd.h>
 #include <stdio.h>
+#include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	int ret;
 
 	ret = truncate("./pirate.txt", 45);

chp2/poll.c

@@ -1,10 +1,11 @@
+#include <poll.h>
 #include <stdio.h>
 #include <unistd.h>
-#include <poll.h>
 
 #define TIMEOUT 5 /* poll timeout, in seconds */
 
-int main(void) {
+int main(void)
+{
 	struct pollfd fds[2];
 	int ret;
 

chp2/select.c

@@ -6,7 +6,8 @@
 #define TIMEOUT 5
 #define BUF_LEN 1024
 
-int main(void) {
+int main(void)
+{
 	struct timeval tv;
 	fd_set readfds;
 	int ret;
@@ -20,13 +21,7 @@ int main(void) {
 	tv.tv_usec = 0;
 
 	/* All right, now block! */
-	ret = select(
-		STDIN_FILENO + 1,
-		&readfds,
-		NULL,
-		NULL,
-		&tv
-	);
+	ret = select(STDIN_FILENO + 1, &readfds, NULL, NULL, &tv);
 	if (ret == -1) {
 		perror("select");
 		return 1;
@@ -42,7 +37,7 @@ int main(void) {
 	 * nonzero, but we will humor ourselves.)
 	 */
 	if (FD_ISSET(STDIN_FILENO, &readfds)) {
-		char buf[BUF_LEN+1];
+		char buf[BUF_LEN + 1];
 		int len;
 
 		/* guaranteed to not block */

chp2/select_regular_files.c

@@ -1,11 +1,11 @@
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <errno.h>
 #include <string.h>
-#include <sys/time.h>
 #include <sys/select.h>
+#include <sys/time.h>
+#include <unistd.h>
 
 #define FILE_NUMBER 3
 #define FILENAME_MAX_LEN 10
@@ -15,7 +15,8 @@
 int create_tmp_file(char *filename);
 void cleanup(char *filenames[]);
 
-int main(void) {
+int main(void)
+{
 	int exit_code = 0;
 	char *filename_template = "test%d.txt";
 	char *filenames[FILE_NUMBER] = {NULL};
@@ -23,22 +24,25 @@ int main(void) {
 
 	// Create a bunch of number ephemeral files
 	for (int i = 0; i < FILE_NUMBER; i++) {
-		char *filename = (char *)malloc(FILENAME_MAX_LEN*sizeof(char)); 
+		char *filename =
+		    (char *)malloc(FILENAME_MAX_LEN * sizeof(char));
 		if (!filename) {
 			perror("malloc failed");
 			exit_code = -1;
 			goto exit;
 		}
-		snprintf(filename, FILENAME_MAX_LEN, filename_template, i+1);
+		snprintf(filename, FILENAME_MAX_LEN, filename_template, i + 1);
 		filenames[i] = filename;
 		printf("Opening file %s...\n", filename);
 		fds[i] = create_tmp_file(filename);
 		if (fds[i] == -1) {
-			fprintf(stderr, "Error to open file %s: %s\n", filename, strerror(errno));
+			fprintf(stderr, "Error to open file %s: %s\n", filename,
+				strerror(errno));
 			exit_code = -1;
 			goto exit;
 		}
-		printf("Open file %s with file descriptor %d\n", filename, fds[i]);
+		printf("Open file %s with file descriptor %d\n", filename,
+		       fds[i]);
 
 		// write something in the files
 		dprintf(fds[i], "Hello I am %s\n", filename);
@@ -50,21 +54,17 @@ int main(void) {
 		FD_SET(fds[i], &readfds);
 	}
 
-	struct timeval *timeout = (struct timeval *)malloc(sizeof(struct timeval));
+	struct timeval *timeout =
+	    (struct timeval *)malloc(sizeof(struct timeval));
 	timeout->tv_sec = TIMEOUT;
 	timeout->tv_usec = 0;
 
-	/* This function do not work with regular files because for the operating system,
-	 * a regular file is ready always.
-         * This example is wrong the best way to use select() is with socket, pipe or other channel types.
+	/* This function do not work with regular files because for the
+	 * operating system, a regular file is ready always. This example is
+	 * wrong the best way to use select() is with socket, pipe or other
+	 * channel types.
 	 */
-	int ret = select(
-		FILE_NUMBER + 1,
-		&readfds,
-		NULL,
-		NULL,
-		timeout
-	);
+	int ret = select(FILE_NUMBER + 1, &readfds, NULL, NULL, timeout);
 
 	if (ret == -1) {
 		fprintf(stderr, "Error to select: %s\n", strerror(errno));
@@ -79,10 +79,11 @@ int main(void) {
 	for (int i = 0; i < FILE_NUMBER; i++) {
 		int fd = fds[i];
 		if (FD_ISSET(fd, &readfds)) {
-			char buf[BUF_LEN+1];
+			char buf[BUF_LEN + 1];
 			int len = read(fd, buf, BUF_LEN);
 			if (len == -1) {
-				fprintf(stderr, "Error reading file %s: %s\n", filenames[i], strerror(errno));
+				fprintf(stderr, "Error reading file %s: %s\n",
+					filenames[i], strerror(errno));
 				exit_code = 1;
 				goto exit;
 			}
@@ -99,7 +100,8 @@ exit:
 		int fd = fds[i];
 		printf("Close file with file descriptor %d\n", fd);
 		if (close(fd) == -1) {
-			fprintf(stderr, "Error to close file %d: %s\n", fd, strerror(errno));
+			fprintf(stderr, "Error to close file %d: %s\n", fd,
+				strerror(errno));
 		}
 	}
 
@@ -112,7 +114,8 @@ exit:
 	return exit_code;
 }
 
-int create_tmp_file(char *filename) {
+int create_tmp_file(char *filename)
+{
 	int fd = open(filename, O_CREAT | O_EXCL | O_RDWR, 0644);
 	if (fd == -1) {
 		return -1;
@@ -120,11 +123,13 @@ int create_tmp_file(char *filename) {
 	return fd;
 }
 
-void cleanup(char *filenames[]) {
+void cleanup(char *filenames[])
+{
 	for (int j = 0; j < FILE_NUMBER; j++) {
 		if (filenames[j] != NULL) {
 			if (remove(filenames[j]) == -1)
-				fprintf(stderr, "Failed to remove %s: %s\n", filenames[j], strerror(errno));
+				fprintf(stderr, "Failed to remove %s: %s\n",
+					filenames[j], strerror(errno));
 			free(filenames[j]);
 			filenames[j] = NULL;
 		}

chp3/binarydata.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 
-int main(void) {
+int main(void)
+{
 	FILE *in, *out;
 	struct pirate {
 		char name[100];		/* real name */
@@ -35,6 +36,7 @@ int main(void) {
 		perror("fclose");
 		return 1;
 	}
-    printf("name=\"%s\" booty=%lu beard_len=%u\n", p.name, p.booty, p.beard_len);
+	printf("name=\"%s\" booty=%lu beard_len=%u\n", p.name, p.booty,
+	       p.beard_len);
 	return 0;
 }

chp3/input.c

@@ -1,7 +1,8 @@
-#include<stdio.h>
 #include <limits.h>
+#include <stdio.h>
 
-int main(void) {
+int main(void)
+{
 	printf("Limit buffer size is %u bytes.\n", LINE_MAX);
 	printf("Buffer size is %u bytes.\n", BUFSIZ);
 }

chp4/blocks.c

@@ -1,10 +1,10 @@
+#include <fcntl.h>
+#include <linux/fs.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <fcntl.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <sys/ioctl.h>
-#include <linux/fs.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 /* get_block - for the file associated with the given fd, returns
  * the physical block mapping to logical_block
@@ -22,7 +22,8 @@ int get_nr_blocks(int fd);
  */
 void print_blocks(int fd);
 
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 	if (argc < 2) {
 		fprintf(stderr, "usage: %s <file>\n", argv[0]);
 		return 1;
@@ -38,7 +39,8 @@ int main(int argc, char *argv[]) {
 	return 0;
 }
 
-int get_block(int fd, int logical_block) {
+int get_block(int fd, int logical_block)
+{
 	int ret = ioctl(fd, FIBMAP, &logical_block);
 	if (ret < 0) {
 		perror("ioctl");
@@ -47,7 +49,8 @@ int get_block(int fd, int logical_block) {
 	return logical_block;
 }
 
-int get_nr_blocks(int fd) {
+int get_nr_blocks(int fd)
+{
 	struct stat buf;
 	int ret = fstat(fd, &buf);
 	if (ret < 0) {
@@ -57,7 +60,8 @@ int get_nr_blocks(int fd) {
 	return buf.st_blocks;
 }
 
-void print_blocks(int fd) {
+void print_blocks(int fd)
+{
 	int nr_blocks = get_nr_blocks(fd);
 	if (nr_blocks < 0) {
 		fprintf(stderr, "get_nr_blocks failed!\n");
@@ -79,7 +83,8 @@ void print_blocks(int fd) {
 			fprintf(stderr, "get_block failed!\n");
 			return;
 		}
-        if (!phys_block) continue;
+		if (!phys_block)
+			continue;
 
 		printf("(%u, %u) ", i, phys_block);
 	}

chp4/inode.c

@@ -1,15 +1,16 @@
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <fcntl.h>
-#include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 
 /* get_inode - returns the inode of the file associated
  * with the given file descriptor, or -1 on failure.
  */
 int get_inode(int fd);
 
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 	if (argc < 2) {
 		fprintf(stderr, "usage: %s <file>\n", argv[0]);
 		return 1;
@@ -27,7 +28,8 @@ int main(int argc, char *argv[]) {
 	return 0;
 }
 
-int get_inode(int fd) {
+int get_inode(int fd)
+{
 	struct stat buf;
 
 	int ret = fstat(fd, &buf);

chp4/mmap.c

@@ -1,11 +1,12 @@
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
-#include <unistd.h>
+#include <stdio.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
 
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 
 	if (argc < 2) {
 		fprintf(stderr, "usage: %s <file>\n", argv[0]);

chp4/readv.c

@@ -1,11 +1,12 @@
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	char foo[48], bar[51], baz[49];
 	int fd = open("buccaneer.txt", O_RDONLY);
 	if (fd == -1) {

chp4/writev.c

@@ -1,19 +1,18 @@
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
+#include <stdio.h>
 #include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	struct iovec iov[3];
 
-    char *buf[] = {
-        "The term buccaneer comes from the word boucan.\n",
+	char *buf[] = {"The term buccaneer comes from the word boucan.\n",
 		       "A boucan is a wooden frame used for cooking meet.\n",
-        "Buccaneer is the West Indies name for a pirate.\n"
-    };
+		       "Buccaneer is the West Indies name for a pirate.\n"};
 
 	int fd = open("buccaneer.txt", O_WRONLY | O_CREAT | O_TRUNC);
 	if (fd == -1) {

chp5/atexit.c

@@ -1,12 +1,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void out(void) {
+void out(void)
+{
 	printf("atexit() succeeded!\n");
 }
 
-
-int main(void) {
+int main(void)
+{
 	if (atexit(out)) {
 		fprintf(stderr, "atexit() failed\n");
 		return 1;

chp5/daemon.c

@@ -1,13 +1,14 @@
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <stdlib.h>
-#include <stdio.h>
 #include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 #include <unistd.h>
 
 #define NR_OPEN 1048576
 
-int main(void) {
+int main(void)
+{
 	// create new process
 	pid_t pid = fork();
 	if (pid == -1) {
@@ -18,10 +19,12 @@ int main(void) {
 	}
 
 	// create a new session and process group
-    if (setsid() == -1) return -1;
+	if (setsid() == -1)
+		return -1;
 
 	// set the working directory to the root directory
-    if (chdir("/") == -1) return -1;
+	if (chdir("/") == -1)
+		return -1;
 
 	// close all open files--NR_OPEN is overkill, but works
 	for (int i = 0; i < NR_OPEN; i++) {

chp5/session.c

@@ -2,7 +2,8 @@
 #define _XOPEN_SOURCE 500
 #include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	printf("My session id=%d\n", getsid(0));
 	printf("My process group id=%d\n", getpgid(0));
 	return 0;

chp5/system.c

@@ -1,9 +1,9 @@
 #include <stdio.h>
 #define _XOPEN_SOURCE
 #include <stdlib.h>
-#include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
 /* my_system - synchronously spawns and waits for the command
  * "/bin/sh -c <cmd>".
@@ -13,7 +13,8 @@
  */
 int my_system(const char *);
 
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 	if (argc < 2) {
 		fprintf(stderr, "usage: %s <command>", argv[0]);
 		return EXIT_FAILURE;
@@ -38,7 +39,8 @@ int main(int argc, char *argv[]) {
 	return status;
 }
 
-int my_system(const char *cmd) {
+int my_system(const char *cmd)
+{
 	pid_t pid = fork();
 	if (pid == -1) {
 		return -1;

chp5/wait.c

@@ -1,9 +1,10 @@
-#include <unistd.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
-int main(void) {
+int main(void)
+{
 	if (!fork())
 		return 1;
 
@@ -16,10 +17,12 @@ int main(void) {
 	printf("pid=%d\n", pid);
 
 	if (WIFEXITED(status))
-        printf("Normal termination with exit status=%d\n", WEXITSTATUS(status));
+		printf("Normal termination with exit status=%d\n",
+		       WEXITSTATUS(status));
 
 	if (WIFSIGNALED(status))
-        printf("Killed by signal=%d%s\n", WTERMSIG(status), WCOREDUMP(status) ? " (dumped core)" : "");
+		printf("Killed by signal=%d%s\n", WTERMSIG(status),
+		       WCOREDUMP(status) ? " (dumped core)" : "");
 
 	if (WIFSTOPPED(status))
 		printf("Stopped by signal=%d\n", WSTOPSIG(status));

chp6/README.md

@@ -0,0 +1,52 @@
+# 📘 Chapter 6 – Advanced Process Management (Summary)
+**From _Linux System Programming_ by Robert Love, 2nd Ed.**
+
+---
+
+## 🔄 Process Scheduling
+- The kernel scheduler selects **runnable processes** (those not blocked on I/O, etc.).
+- Goals: **maximize CPU utilization**, minimize wait time, and ensure fairness :contentReference[oaicite:1]{index=1}.
+- Covers **preemptive scheduling**, **timeslices**, and the Linux **Completely Fair Scheduler (CFS)**.
+- Explains **processor affinity** and CPU sets: binding processes to specific CPUs for cache performance :contentReference[oaicite:2]{index=2}.
+
+## 🧭 Yielding the Processor
+- `sched_yield()` lets a running process give up the CPU voluntarily.
+- Useful in busy-wait loops or when expecting immediate CPU from others :contentReference[oaicite:3]{index=3}.
+
+## 🎚️ Priorities & Nice Values
+- Processes can adjust their priority using **`nice()`**, where lower nice = higher priority.
+- Real-time scheduling policies (`SCHED_FIFO`, `SCHED_RR`) grant stronger priority guarantees for time-sensitive tasks :contentReference[oaicite:4]{index=4}.
+
+## 🧠 Processor Affinity
+- **Get/set CPU affinity** with `sched_getaffinity()` and `sched_setaffinity()`.
+- Ensures cache affinity, reducing context-switch overhead :contentReference[oaicite:5]{index=5}.
+
+## ⏱️ Real-Time Scheduling
+- Differences between **hard** and **soft real-time** systems.
+- Configurable policies: `SCHED_FIFO`, `SCHED_RR`, with real-time priority range 0–99 :contentReference[oaicite:6]{index=6}.
+- Care needed: real-time tasks can lead to starvation of normal tasks.
+
+## 🔒 Resource Limits
+- Kernel enforces per-process limits via `setrlimit()`/`getrlimit()`:
+  - CPU usage (`RLIMIT_CPU`)
+  - File sizes (`RLIMIT_FSIZE`)
+  - Number of open files, memory, etc. :contentReference[oaicite:7]{index=7}.
+- Helps contain rogue or misbehaving processes, essential for robustness.
+
+---
+
+## ✅ Why It Matters
+Advanced control over process scheduling, priorities, affinity, and resource limits is critical for writing:
+- Real-time or latency-sensitive applications
+- High-performance servers that benefit from core binding
+- Robust daemons that avoid resource exhaustion
+
+This chapter equips systems programmers with the tools to finely tune how tasks interact with the kernel scheduler and manage system impact.
+
+---
+
+## 📚 References
+- *Linux System Programming*, 2nd Ed. — Robert Love  
+- `man 2 sched_setscheduler`, `man 2 setrlimit`, `man 2 sched_getaffinity`  
+- Wikipedia: [Completely Fair Scheduler](https://en.wikipedia.org/wiki/Completely_Fair_Scheduler) :contentReference[oaicite:8]{index=8}
+

exercises/mycp/main.c

@@ -1,13 +1,13 @@
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <fcntl.h>
-#include <errno.h>
 
 #define BUFF_LEN 4096
 
-
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 	// Check number of arguments
 	if (argc < 3) {
 		fprintf(stderr, "Usage: %s SOURCE DEST\n", argv[0]);
@@ -25,7 +25,8 @@ int main(int argc, char *argv[]) {
 		return EXIT_FAILURE;
 	}
 
-    // Open destination file in write mode, if exists trunc file otherwise create a new file
+	// Open destination file in write mode, if exists trunc file otherwise
+	// create a new file
 	int dstfd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 	if (dstfd == -1) {
 		perror("Failed open destination file");
@@ -41,7 +42,8 @@ int main(int argc, char *argv[]) {
 	while ((read_bytes = read(srcfd, buff, BUFF_LEN)) != 0) {
 		if (read_bytes == -1) {
 			// There is an error for reading source file
-            if (errno == EINTR) continue;
+			if (errno == EINTR)
+				continue;
 			perror("Failed to read source file");
 			exit_code = EXIT_FAILURE;
 			break;

exercises/tree/main.c

@@ -1,8 +1,9 @@
+#include "tree.h"
 #include <stdio.h>
 #include <stdlib.h>
-#include "tree.h"
 
-int main(int argc, char *argv[]) {
+int main(int argc, char *argv[])
+{
 	const char *path = (argc > 1) ? argv[1] : ".";
 
 	if (print_tree(path, 0) == -1) {
@@ -12,4 +13,3 @@ int main(int argc, char *argv[]) {
 
 	return EXIT_SUCCESS;
 }
-

exercises/tree/tree.c

@@ -1,27 +1,32 @@
+#include "tree.h"
+#include <dirent.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <dirent.h>
 #include <sys/stat.h>
 #include <unistd.h>
-#include "tree.h"
 
-int print_tree(const char *path, int depth) {
+int print_tree(const char *path, int depth)
+{
 	DIR *dir = opendir(path);
-    if (!dir) return -1;
+	if (!dir)
+		return -1;
 
 	struct dirent *entry;
 	while ((entry = readdir(dir)) != NULL) {
 		// Skip . and ..
-        if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+		if (strcmp(entry->d_name, ".") == 0 ||
+		    strcmp(entry->d_name, "..") == 0)
 			continue;
 
-        for (int i = 0; i < depth; i++) printf("  ");
+		for (int i = 0; i < depth; i++)
+			printf("  ");
 		printf("|-- %s\n", entry->d_name);
 
 		// Construct full path
 		char full_path[4096];
-        snprintf(full_path, sizeof(full_path), "%s/%s", path, entry->d_name);
+		snprintf(full_path, sizeof(full_path), "%s/%s", path,
+			 entry->d_name);
 
 		struct stat st;
 		if (stat(full_path, &st) == 0 && S_ISDIR(st.st_mode)) {
@@ -32,4 +37,3 @@ int print_tree(const char *path, int depth) {
 	closedir(dir);
 	return 0;
 }
-

exercises/tree/tree.h

@@ -4,4 +4,3 @@
 int print_tree(const char *path, int depth);
 
 #endif
-