C Lecture - 1

Mon, 01 Jan 0001 00:00:00 +0000

Author: Zed A. Shaw

All content comes from Zed’s Lecture Repository and Libraries Repository. All credit goes to Zed.

Exercise 0 Installing Software#

The Plan

Install software on your system.
Test that it works right.

Linux Install

On Debian/Ubuntu use:

$ sudo apt-get install build-essential

On RedHat/CentOS:

$ sudo yum groupinstall development-tools

Linux Testing

Test that your C compiler works with:

$ cc --version

OSX Install

Install XCode, this will take a while.

C Lecture - 2

Mon, 01 Jan 0001 00:00:00 +0000

Author: Zed A. Shaw

All content comes from Zed’s Lecture Repository and Libraries Repository. All credit goes to Zed.

Exercise 32 Double Linked Lists#

The Plan

Learn about your very first data structure:

Double Linked Lists

Creating A liblcthw Project

We’ll need a project for the rest of the book called liblcthw.

Algorithms and Data Structures

A big step in going from amateur to professional is learning about data structures and algorithms.

C Lecture - 3

Mon, 01 Jan 0001 00:00:00 +0000

Author: Zed A. Shaw

All content comes from Zed’s Lecture Repository and Libraries Repository. All credit goes to Zed.

Exercise 41 Project devpkg#

.\ex41\devpkg

.\ex41\devpkg\commands.c

#include <apr_uri.h>
#include <apr_fnmatch.h>
#include <unistd.h>

#include "commands.h"
#include "dbg.h"
#include "bstrlib.h"
#include "db.h"
#include "shell.h"

int Command_depends(apr_pool_t * p, const char *path)
{
 FILE *in = NULL;
 bstring line = NULL;

 in = fopen(path, "r");
 check(in != NULL, "Failed to open downloaded depends: %s", path);

 for (line = bgets((bNgetc) fgetc, in, '\n');
 line != NULL; 
 line = bgets((bNgetc) fgetc, in, '\n')) 
 {
 btrimws(line);
 log_info("Processing depends: %s", bdata(line));
 int rc = Command_install(p, bdata(line), NULL, NULL, NULL);
 check(rc == 0, "Failed to install: %s", bdata(line));
 bdestroy(line);
 }

 fclose(in);
 return 0;

error:
 if (line) bdestroy(line);
 if (in) fclose(in);
 return -1;
}

int Command_fetch(apr_pool_t * p, const char *url, int fetch_only)
{
 apr_uri_t info = {.port = 0 };
 int rc = 0;
 const char *depends_file = NULL;
 apr_status_t rv = apr_uri_parse(p, url, &info);

 check(rv == APR_SUCCESS, "Failed to parse URL: %s", url);

 if (apr_fnmatch(GIT_PAT, info.path, 0) == APR_SUCCESS) {
 rc = Shell_exec(GIT_SH, "URL", url, NULL);
 check(rc == 0, "git failed.");
 } else if (apr_fnmatch(DEPEND_PAT, info.path, 0) == APR_SUCCESS) {
 check(!fetch_only, "No point in fetching a DEPENDS file.");

 if (info.scheme) {
 depends_file = DEPENDS_PATH;
 rc = Shell_exec(CURL_SH, "URL", url, "TARGET", depends_file,
 NULL);
 check(rc == 0, "Curl failed.");
 } else {
 depends_file = info.path;
 }

 // recursively process the devpkg list
 log_info("Building according to DEPENDS: %s", url);
 rv = Command_depends(p, depends_file);
 check(rv == 0, "Failed to process the DEPENDS: %s", url);

 // this indicates that nothing needs to be done
 return 0;

 } else if (apr_fnmatch(TAR_GZ_PAT, info.path, 0) == APR_SUCCESS) {
 if (info.scheme) {
 rc = Shell_exec(CURL_SH,
 "URL", url, "TARGET", TAR_GZ_SRC, NULL);
 check(rc == 0, "Failed to curl source: %s", url);
 }

 rv = apr_dir_make_recursive(BUILD_DIR,
 APR_UREAD | APR_UWRITE |
 APR_UEXECUTE, p);
 check(rv == APR_SUCCESS, "Failed to make directory %s",
 BUILD_DIR);

 rc = Shell_exec(TAR_SH, "FILE", TAR_GZ_SRC, NULL);
 check(rc == 0, "Failed to untar %s", TAR_GZ_SRC);
 } else if (apr_fnmatch(TAR_BZ2_PAT, info.path, 0) == APR_SUCCESS) {
 if (info.scheme) {
 rc = Shell_exec(CURL_SH, "URL", url, "TARGET", TAR_BZ2_SRC,
 NULL);
 check(rc == 0, "Curl failed.");
 }

 apr_status_t rc = apr_dir_make_recursive(BUILD_DIR,
 APR_UREAD | APR_UWRITE
 | APR_UEXECUTE, p);

 check(rc == 0, "Failed to make directory %s", BUILD_DIR);
 rc = Shell_exec(TAR_SH, "FILE", TAR_BZ2_SRC, NULL);
 check(rc == 0, "Failed to untar %s", TAR_BZ2_SRC);
 } else {
 sentinel("Don't now how to handle %s", url);
 }

 // indicates that an install needs to actually run
 return 1;
error:
 return -1;
}

int Command_build(apr_pool_t * p, const char *url,
 const char *configure_opts, const char *make_opts,
 const char *install_opts)
{
 int rc = 0;

 check(access(BUILD_DIR, X_OK | R_OK | W_OK) == 0,
 "Build directory doesn't exist: %s", BUILD_DIR);

 // actually do an install
 if (access(CONFIG_SCRIPT, X_OK) == 0) {
 log_info("Has a configure script, running it.");
 rc = Shell_exec(CONFIGURE_SH, "OPTS", configure_opts, NULL);
 check(rc == 0, "Failed to configure.");
 }

 rc = Shell_exec(MAKE_SH, "OPTS", make_opts, NULL);
 check(rc == 0, "Failed to build.");

 rc = Shell_exec(INSTALL_SH,
 "TARGET", install_opts ? install_opts : "install",
 NULL);
 check(rc == 0, "Failed to install.");

 rc = Shell_exec(CLEANUP_SH, NULL);
 check(rc == 0, "Failed to cleanup after build.");

 rc = DB_update(url);
 check(rc == 0, "Failed to add this package to the database.");

 return 0;

error:
 return -1;
}

int Command_install(apr_pool_t * p, const char *url,
 const char *configure_opts, const char *make_opts,
 const char *install_opts)
{
 int rc = 0;
 check(Shell_exec(CLEANUP_SH, NULL) == 0,
 "Failed to cleanup before building.");

 rc = DB_find(url);
 check(rc != -1, "Error checking the install database.");

 if (rc == 1) {
 log_info("Package %s already installed.", url);
 return 0;
 }

 rc = Command_fetch(p, url, 0);

 if (rc == 1) {
 rc = Command_build(p, url, configure_opts, make_opts,
 install_opts);
 check(rc == 0, "Failed to build: %s", url);
 } else if (rc == 0) {
 // no install needed
 log_info("Depends successfully installed: %s", url);
 } else {
 // had an error
 sentinel("Install failed: %s", url);
 }

 Shell_exec(CLEANUP_SH, NULL);
 return 0;

error:
 Shell_exec(CLEANUP_SH, NULL);
 return -1;
}

.\ex41\devpkg\commands.h

C Lecture - 4

Mon, 01 Jan 0001 00:00:00 +0000

Author: Zed A. Shaw

All content comes from Zed’s Lecture Repository and Libraries Repository. All credit goes to Zed.

Exercise 48a A Simple Network Server:#

Project Description

The Plan

Start your first long running project:

statserve

The Purpose

You’ll get the project started and get a minimum first hack going.

The Requirements

Create a simple network server that accepts a connection on port 7899 from netclient or the nc command, and echoes back anything you type.
You’ll need to learn how to bind a port, listen on the socket, and answer it. Use your research skills to study how this is done and attempt to implement it yourself.

The Requirements

C on My Notes

C Lecture - 1

Exercise 0 Installing Software#

C Lecture - 2

Exercise 32 Double Linked Lists#

C Lecture - 3

Exercise 41 Project devpkg#

C Lecture - 4

Exercise 48a A Simple Network Server:#