Finish initial implementation

Makefile

@@ -1,7 +1,7 @@
 CC=gcc
-CFLAGS=-Wall -Wextra -Wpedantic -std=c23 -D_POSIX_C_SOURCE=200112L -O2
+CFLAGS=-Wall -Wextra -Wpedantic -std=c23 -D_POSIX_C_SOURCE=200809L -pthread -O2
 CFLAGS+=-Og -g -fsanitize=address,undefined
-SRCS=main.c threadpool.c util.c
+SRCS=main.c threadpool.c util.c server.c http.c
 
 OBJS=$(SRCS:%.c=bin/%.o)
 
@@ -10,9 +10,10 @@ all: httpserver
 httpserver: $(OBJS)
 	$(CC) $(CFLAGS) -o $@ $^
 
-bin/%.o: src/%.c
+# Auto-rebuild if Makefile changes
+bin/%.o: src/%.c Makefile
 	@mkdir -p bin/deps/
-	$(CC) $(CFLAGS) -MD -MF $(patsubst src/%.c,bin/deps/%.d,$^) -c -o $@ $^
+	$(CC) $(CFLAGS) -MD -MF $(patsubst src/%.c,bin/deps/%.d,$<) -c -o $@ $<
 
 include $(SRCS:%.c/bin/deps/%.d)
 

src/http.c

@@ -0,0 +1,236 @@
+#include "http.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static const char *EMPTY_STRING = "";
+
+HTTPHeaderList *http_header_list_push(HTTPHeaderList *list, const char *key,
+                                      const char *value) {
+    HTTPHeaderList *new = malloc(sizeof(HTTPHeaderList));
+    if (!new) {
+        return NULL;
+    }
+    new->key_length = strlen(key);
+    new->key = malloc(new->key_length + 1);
+    if (!new->key) {
+        free(new);
+        return NULL;
+    }
+    memcpy(new->key, key, new->key_length + 1);
+    new->value_length = strlen(value);
+    new->value = malloc(new->value_length + 1);
+    if (!new->value) {
+        free(new->key);
+        free(new);
+        return NULL;
+    }
+    memcpy(new->value, value, new->value_length + 1);
+    new->next = list;
+    return new;
+}
+
+void free_http_header_list(HTTPHeaderList *list) {
+    while (list) {
+        HTTPHeaderList *next = list->next;
+        free(list->key);
+        free(list->value);
+        free(list);
+        list = next;
+    }
+}
+
+const char *http_header_list_search(HTTPHeaderList *list, const char *key,
+                                    const char *def) {
+    while (list) {
+        if (strcmp(list->key, key) == 0) {
+            return list->value;
+        }
+        list = list->next;
+    }
+    return def;
+}
+
+#define MAX_REQUEST_LENGTH      16384
+#define MAX_METHOD_LENGTH       16
+#define MAX_URI_LENGTH          256
+#define MAX_VERSION_LENGTH      3
+#define MAX_HEADER_KEY_LENGTH   2048
+#define MAX_HEADER_VALUE_LENGTH 2048
+
+#define RETURN_IF_READ_ERROR(s)  \
+    if (ferror((s))) {           \
+        return HRPR_READ_FAILED; \
+    }
+
+// if an error occured, req->uri is not allocated
+static HTTPRequestParseResult parse_method_uri_line(FILE *stream,
+                                                    size_t *restrict bytes_read,
+                                                    HTTPRequest *restrict req) {
+    // allow for some leeway in passing incorrect methods
+    char method[MAX_METHOD_LENGTH + 1];
+    char uri[MAX_URI_LENGTH + 1];
+    char version_str[MAX_VERSION_LENGTH + 1];
+    char whitespace[4];
+    ssize_t signed_bytes_read;
+#define S1(s) #s
+#define S(s)  S1(s)
+    int nconv = fscanf(
+        stream,
+        // clang-format off
+        "%" S(MAX_METHOD_LENGTH) "[A-Z]"
+        "%c"
+        "%" S(MAX_URI_LENGTH) "[^ \n\r]"
+        "%c"
+        "HTTP/%" S(MAX_VERSION_LENGTH) "[0-9.]"
+        "%c%c"
+        "%zn",
+        // clang-format on
+        method, &whitespace[0], uri, &whitespace[1], version_str,
+        &whitespace[2], &whitespace[3], &signed_bytes_read);
+#undef S
+    *bytes_read = signed_bytes_read;
+    RETURN_IF_READ_ERROR(stream);
+    if (nconv != 7 || memcmp(whitespace, "  \r\n", 4) != 0) {
+        return HRPR_BAD_FORMAT;
+    }
+    req->method = strdup(method);
+    if (!req->method) {
+        return HRPR_NO_MEM;
+    }
+    req->uri = strdup(uri);
+    if (!req->uri) {
+        return HRPR_NO_MEM;
+    }
+    req->path = req->uri;
+    while (*req->path == '/') {
+        ++req->path;
+    }
+    return strcmp(version_str, "1.1") == 0 ? HRPR_OK : HRPR_BAD_VERSION;
+}
+
+// return true if there are more headers and no error occurred, false otherwise
+// this will *not* free LIST if an error occurs
+static bool next_header(FILE *stream, size_t *restrict bytes_read,
+                        HTTPRequestParseResult *restrict res,
+                        HTTPHeaderList *restrict *restrict list) {
+    char c = fgetc(stream);
+    RETURN_IF_READ_ERROR(stream);
+    if (c == '\r') {
+        c = fgetc(stream);
+        RETURN_IF_READ_ERROR(stream);
+        if (c != '\n') {
+            *res = HRPR_BAD_FORMAT;
+            return false;
+        }
+        *bytes_read = 2;
+        *res = HRPR_OK;
+        return false;
+    }
+    ungetc(c, stream);
+    char key[MAX_HEADER_KEY_LENGTH + 1];
+    char value[MAX_HEADER_VALUE_LENGTH + 1];
+    char whitespace[3];
+    ssize_t signed_bytes_read;
+#define S1(s) #s
+#define S(s)  S1(s)
+    int nconv =
+        fscanf(stream,
+               // clang-format off
+               "%" S(MAX_HEADER_KEY_LENGTH) "[a-zA-Z0-9.-]"
+               ":%c"
+               "%" S(MAX_HEADER_VALUE_LENGTH) "[ -~]"
+               "%c%c"
+               "%zn",
+               // clang-format on
+               key, &whitespace[0], value, &whitespace[1], &whitespace[2],
+               &signed_bytes_read);
+#undef S
+    *bytes_read = signed_bytes_read;
+    RETURN_IF_READ_ERROR(stream);
+    if (nconv != 5 || memcmp(whitespace, " \r\n", 3) != 0) {
+        return HRPR_BAD_FORMAT;
+    }
+    *list = http_header_list_push(*list, key, value);
+    if (!*list) {
+        *res = HRPR_NO_MEM;
+        return false;
+    }
+    return true;
+}
+
+HTTPRequestParseResult parse_http_request(FILE *stream,
+                                          HTTPRequest *restrict out) {
+    out->uri = EMPTY_STRING;
+    out->path = EMPTY_STRING;
+    out->method = EMPTY_STRING;
+    size_t total_bytes;
+    HTTPRequestParseResult res;
+    if ((res = parse_method_uri_line(stream, &total_bytes, out)) != HRPR_OK) {
+        return res;
+    }
+    out->headers = NULL;
+    size_t bytes_read;
+    while (next_header(stream, &bytes_read, &res, &out->headers)) {
+        if ((total_bytes += bytes_read) > MAX_REQUEST_LENGTH) {
+            res = HRPR_BAD_FORMAT;
+            break;
+        }
+    }
+    return res;
+}
+
+void free_http_request(HTTPRequest *restrict req) {
+    if (req->method != EMPTY_STRING) {
+        free((char *) req->method);
+    }
+    if (req->uri != EMPTY_STRING) {
+        free((char *) req->uri);
+    }
+    free_http_header_list(req->headers);
+}
+
+const char *status_code_to_message(int status, size_t *restrict length) {
+    static const struct {
+        int code;
+        const char *msg;
+        size_t size;
+    } CODES[] = {
+#define P(s, m) {s, m, sizeof(m) - 1}
+        P(200, "OK"),
+        P(201, "Created"),
+        P(400, "Bad Request"),
+        P(403, "Forbidden"),
+        P(404, "Not Found"),
+        P(500, "Internal Server Error"),
+        P(501, "Not Implemented"),
+        P(505, "Version Not Supported"),
+#undef P
+    };
+    static const size_t NCODES = sizeof(CODES) / sizeof(CODES[0]);
+    for (size_t i = 0; i < NCODES; ++i) {
+        if (status == CODES[i].code) {
+            if (length) {
+                *length = CODES[i].size;
+            }
+            return CODES[i].msg;
+        }
+    }
+    return NULL;
+}
+
+void format_http_response(FILE *stream, HTTPResponse *restrict resp) {
+    assert(status_code_to_message(resp->status, NULL));
+    fprintf(stream, "HTTP/1.1 %d %s\r\n", resp->status,
+            status_code_to_message(resp->status, NULL));
+    fprintf(stream, "Content-Length: %zu\r\n", resp->body_length);
+    for (HTTPHeaderList *h = resp->headers; h; h = h->next) {
+        fwrite(h->key, 1, h->key_length, stream);
+        fwrite(": ", 1, 2, stream);
+        fwrite(h->value, 1, h->value_length, stream);
+        fwrite("\r\n", 1, 2, stream);
+    }
+    fwrite("\r\n", 1, 2, stream);
+}

src/http.h

@@ -0,0 +1,57 @@
+#ifndef INCLUDED_HTTP_H
+#define INCLUDED_HTTP_H
+
+#include <stddef.h>
+#include <stdio.h>
+
+typedef struct _HTTPHeaderList HTTPHeaderList;
+
+struct _HTTPHeaderList {
+    char *key;
+    size_t key_length;
+    char *value;
+    size_t value_length;
+    HTTPHeaderList *next;
+};
+
+HTTPHeaderList *http_header_list_push(HTTPHeaderList *list, const char *key,
+                                      const char *value);
+
+void free_http_header_list(HTTPHeaderList *list);
+
+const char *http_header_list_search(HTTPHeaderList *list, const char *key,
+                                    const char *def);
+
+typedef enum {
+    HRPR_OK,
+    HRPR_NO_MEM,
+    HRPR_BAD_VERSION,
+    HRPR_BAD_FORMAT,
+    HRPR_READ_FAILED,
+} HTTPRequestParseResult;
+
+typedef struct {
+    const char *method;
+    const char *uri;
+    // relative (shares memory with uri)
+    const char *path;
+
+    HTTPHeaderList *headers;
+} HTTPRequest;
+
+HTTPRequestParseResult parse_http_request(FILE *stream,
+                                          HTTPRequest *restrict out);
+
+void free_http_request(HTTPRequest *restrict req);
+
+typedef struct {
+    int status;
+    HTTPHeaderList *headers;
+    size_t body_length;
+} HTTPResponse;
+
+const char *status_code_to_message(int status, size_t *restrict length);
+
+void format_http_response(FILE *stream, HTTPResponse *restrict resp);
+
+#endif

src/main.c

@@ -1,17 +1,25 @@
+#include "http.h"
+#include "server.h"
+#include "threadpool.h"
 #include "util.h"
 
 #include <ctype.h>
 #include <errno.h>
-#include <limits.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 typedef struct {
     bool opt_error;
     bool help_flag;
-    int port;
-    int parallelism;
+    uint32_t port;
+    size_t parallelism;
+    const char *address;
 } GlobalFlags;
 
 static const GlobalFlags DEFAULT_FLAGS = {
@@ -19,18 +27,24 @@ static const GlobalFlags DEFAULT_FLAGS = {
     .help_flag = false,
     .port = 0,
     .parallelism = 1,
+    .address = "127.0.0.1",
 };
 
 // Return false on failure, true on success
-static bool parse_int(const char *str, int min, int max, int *output) {
+static bool parse_uint(const char *str, uintmax_t min, uintmax_t max,
+                       uintmax_t *output) {
+    if (isspace(*str) || *str == '+' || *str == '-') {
+        log_error("malformed number: \"%s\"", str);
+        return false;
+    }
     errno = 0;
     char *endptr;
-    long conv = strtol(str, &endptr, 10);
+    uintmax_t conv = strtoumax(str, &endptr, 10);
     if (!*str || *endptr) {
         log_error("malformed number: \"%s\"", str);
         return false;
-    } else if (((conv == LONG_MIN || conv == LONG_MAX) && errno == ERANGE)
-               || conv < min || conv > max) {
+    } else if ((conv == UINTMAX_MAX && errno == ERANGE) || conv < min
+               || conv > max) {
         log_error("out of range: %s", str);
         return false;
     }
@@ -38,31 +52,36 @@ static bool parse_int(const char *str, int min, int max, int *output) {
     return true;
 }
 
-void parse_cli_options(int argc, const char **argv, GlobalFlags *flags) {
-    constexpr unsigned long MAX_PARALLELISM = INT_MAX;
-    constexpr unsigned long MAX_PORT = 65535;
+static void parse_cli_options(int argc, const char **argv, GlobalFlags *flags) {
+    constexpr size_t MAX_PARALLELISM = SIZE_MAX;
+    constexpr uint32_t MAX_PORT = 65535;
     opterr = false;
     int c;
     char pretty_flag[8];
-    while ((c = getopt(argc, (char *const *) argv, "hp:")) >= 0) {
+    while ((c = getopt(argc, (char *const *) argv, ":ha:p:")) >= 0) {
         if (isprint(c)) {
-            snprintf(pretty_flag, sizeof(pretty_flag), "%c", c);
+            snprintf(pretty_flag, sizeof(pretty_flag), "%c", optopt);
         } else {
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-truncation"
             // `c` is actually in the range [0,255], and so will be at most 2
             // hex digits
-            snprintf(pretty_flag, sizeof(pretty_flag), "0x%02x", c);
+            snprintf(pretty_flag, sizeof(pretty_flag), "0x%02x", optopt);
 #pragma GCC diagnostic pop
         }
         switch (c) {
         case 'h':
             flags->help_flag = true;
             return;
-        case 'p':
-            if (!parse_int(optarg, 1, MAX_PARALLELISM, &flags->parallelism)) {
+        case 'p': {
+            uintmax_t conv;
+            if (!parse_uint(optarg, 1, MAX_PARALLELISM, &conv)) {
                 flags->opt_error = true;
             }
+            flags->parallelism = conv;
+        } break;
+        case 'a':
+            flags->address = optarg;
             break;
         case ':':
             flags->opt_error = true;
@@ -74,28 +93,242 @@ void parse_cli_options(int argc, const char **argv, GlobalFlags *flags) {
             break;
         }
     }
-    if (optind == argc) {
+    uintmax_t port_conv;
+    if (flags->opt_error) {
+        return;
+    } else if (optind == argc) {
         flags->opt_error = true;
         log_error("no port provided");
     } else if (optind != argc - 1) {
         flags->opt_error = true;
         log_error("extra positional arguments after port");
-    } else if (!parse_int(argv[optind], 1, MAX_PORT, &flags->port)) {
+    } else if (!parse_uint(argv[optind], 1, MAX_PORT, &port_conv)) {
         flags->opt_error = true;
+    } else {
+        flags->port = port_conv;
     }
 }
 
-void print_help(FILE *file) {
-    fprintf(file, "usage: httpserver [-h] [-p PARALLELISM] <PORT>\n");
+static void print_help(FILE *file) {
+    fprintf(file,
+            "usage: httpserver [-h] [-a ADDRESS] [-p PARALLELISM] <PORT>\n");
     fprintf(file, " -h  print this message, then exit\n");
     fprintf(
         file,
         " -p  use PARALLELISM threads for processing requests (default: 1)\n");
+    fprintf(file, " -a  bind to ADDRESS (default: 127.0.0.1)\n");
+}
+
+constexpr int WORKER_BLOCKED_SIGNALS[] = {SIGTERM, SIGINT, SIGHUP};
+constexpr size_t N_WORKER_BLOCKED_SIGNALS =
+    sizeof(WORKER_BLOCKED_SIGNALS) / sizeof(int);
+static bool shutdown_flag = false;
+
+static void signal_handler(int signal) {
+    if (shutdown_flag) {
+        _exit(signal == SIGTERM ? 0 : EXIT_FAILURE);
+    }
+    shutdown_flag = true;
+}
+
+static void setup_signals() {
+    struct sigaction act = {
+        .sa_handler = signal_handler,
+        .sa_flags = 0,
+    };
+    sigemptyset(&act.sa_mask);
+    for (size_t i = 0; i < N_WORKER_BLOCKED_SIGNALS; ++i) {
+        if (sigaction(WORKER_BLOCKED_SIGNALS[i], &act, NULL) < 0) {
+            log_errno("sigaction");
+            exit(EXIT_FAILURE);
+        }
+    }
+}
+
+static int parse_result_to_status(HTTPRequestParseResult res) {
+    switch (res) {
+    case HRPR_OK:
+        return 200;
+    case HRPR_NO_MEM:
+    case HRPR_READ_FAILED:
+        return 500;
+    case HRPR_BAD_VERSION:
+        return 505;
+    case HRPR_BAD_FORMAT:
+        return 400;
+    default:
+        abort();
+    }
+}
+
+static void send_simple_response(FILE *stream, int status) {
+    size_t status_msg_len;
+    const char *status_msg = status_code_to_message(status, &status_msg_len);
+    HTTPResponse resp = {
+        .status = status,
+        .headers = NULL,
+        .body_length = status_msg_len + 1,
+    };
+    format_http_response(stream, &resp);
+    fwrite(status_msg, 1, status_msg_len, stream);
+    fputc('\n', stream);
+}
+
+static void write_audit_log_entry(HTTPRequest *restrict req, int status) {
+    fprintf(stderr, "%s,%s,%d,%s\n", req->method, req->uri, status,
+            http_header_list_search(req->headers, "Request-ID", "0"));
+}
+
+static void handle_get_request(FILE *conn, HTTPRequest *restrict req) {
+    int status = 200;
+    struct stat statbuf;
+    flockfile(stderr);
+    FILE *file_handle = fopen(req->path, "r");
+    if (!file_handle) {
+        if (errno == ENOENT) {
+            status = 404;
+        } else if (errno == EACCES) {
+            status = 403;
+        } else {
+            status = 500;
+        }
+    }
+    if (file_handle && fstat(fileno(file_handle), &statbuf) < 0) {
+        status = errno == EACCES ? 403 : 500;
+    }
+    write_audit_log_entry(req, status);
+    funlockfile(stderr);
+    if (status != 200) {
+        if (file_handle) {
+            fclose(file_handle);
+        }
+        send_simple_response(conn, status);
+        return;
+    }
+    HTTPResponse resp = {
+        .status = 200,
+        .headers = NULL,
+        .body_length = statbuf.st_size,
+    };
+    format_http_response(conn, &resp);
+    char read_buf[4096];
+    while (!feof(file_handle)) {
+        if (ferror(file_handle)) {
+            // can't really do anything about it here, just break
+            break;
+        }
+        size_t count = fread(read_buf, 1, sizeof(read_buf), file_handle);
+        if (count) {
+            fwrite(read_buf, 1, count, conn);
+        }
+    }
+    fclose(file_handle);
+}
+
+static ssize_t get_content_length(HTTPRequest *restrict req) {
+    const char *text =
+        http_header_list_search(req->headers, "Content-Length", NULL);
+    if (!text) {
+        return 0;
+    } else if (isspace(*text) || *text == '-' || *text == '+') {
+        return -1;
+    }
+    char *endptr;
+    uintmax_t conv = strtoumax(text, &endptr, 10);
+    if (*endptr || (conv == UINTMAX_MAX && errno == ERANGE)
+        || conv > SIZE_MAX) {
+        return -1;
+    }
+    return conv;
+}
+
+static void handle_put_request(FILE *conn, HTTPRequest *restrict req) {
+    ssize_t content_length = get_content_length(req);
+    if (content_length < 0) {
+        write_audit_log_entry(req, 400);
+        send_simple_response(conn, 400);
+        fclose(conn);
+        return;
+    }
+    char temp_file[] = "temp_fileXXXXXX";
+    int temp_fd = mkstemp(temp_file);
+    if (temp_fd < 0) {
+        write_audit_log_entry(req, 500);
+        send_simple_response(conn, 500);
+        return;
+    }
+    char read_buff[4096];
+    while (content_length) {
+        ssize_t read_size = fread(read_buff, 1,
+                                  (size_t) content_length < sizeof(read_buff)
+                                      ? (size_t) content_length
+                                      : sizeof(read_buff),
+                                  conn);
+        if (ferror(conn) || write(temp_fd, read_buff, read_size) < 0) {
+            write_audit_log_entry(req, 500);
+            send_simple_response(conn, 500);
+            close(temp_fd);
+            unlink(temp_file);
+            return;
+        }
+        content_length -= read_size;
+    }
+    close(temp_fd);
+    int status;
+    bool need_unlink = true;
+    flockfile(stderr);
+    int creat_fd = open(req->path, O_RDONLY | O_CREAT | O_EXCL, 0644);
+    if (creat_fd < 0 && errno == EEXIST) {
+        // file existed
+        status = 200;
+    } else if (creat_fd <= 0) {
+        // actual error
+        status = errno == EACCES ? 403 : 500;
+        goto write_status_and_unlock;
+    } else {
+        // created the file
+        status = 201;
+        close(creat_fd);
+    }
+    if (rename(temp_file, req->path) < 0) {
+        status = errno == EACCES ? 403 : 500;
+        goto write_status_and_unlock;
+    }
+    need_unlink = false;
+write_status_and_unlock:
+    write_audit_log_entry(req, status);
+    funlockfile(stderr);
+    send_simple_response(conn, status);
+    if (need_unlink) {
+        unlink(temp_file);
+    }
+}
+
+static void handle_connection(void *arg) {
+    FILE *conn = arg;
+    HTTPRequest req;
+    HTTPRequestParseResult res = parse_http_request(conn, &req);
+    if (res != HRPR_OK) {
+        int status = parse_result_to_status(res);
+        write_audit_log_entry(&req, status);
+        send_simple_response(conn, status);
+    } else if (strchr(req.path, '/')) {
+        write_audit_log_entry(&req, 400);
+        send_simple_response(conn, 400);
+    } else if (strcmp(req.method, "GET") == 0) {
+        handle_get_request(conn, &req);
+    } else if (strcmp(req.method, "PUT") == 0) {
+        handle_put_request(conn, &req);
+    } else {
+        write_audit_log_entry(&req, 501);
+        send_simple_response(conn, 501);
+    }
+    free_http_request(&req);
+    fclose(conn);
 }
 
 int main(int argc, const char **argv) {
     setenv("POSIXLY_CORRECT", "1", true);
-    set_exec_name(argv[0]);
     GlobalFlags flags = DEFAULT_FLAGS;
     parse_cli_options(argc, argv, &flags);
     if (flags.help_flag) {
@@ -104,7 +337,39 @@ int main(int argc, const char **argv) {
     } else if (flags.opt_error) {
         return EXIT_FAILURE;
     }
-    printf("Port: %d\n", flags.port);
-    printf("Parallelism: %d\n", flags.parallelism);
+    sigset_t worker_block_set;
+    sigemptyset(&worker_block_set);
+    for (size_t i = 0; i < N_WORKER_BLOCKED_SIGNALS; ++i) {
+        sigaddset(&worker_block_set, WORKER_BLOCKED_SIGNALS[i]);
+    }
+    Server *server = make_server(flags.address, flags.port);
+    if (!server) {
+        return EXIT_FAILURE;
+    }
+    ThreadPool *pool = make_thread_pool(flags.parallelism, worker_block_set);
+    if (!pool) {
+        destroy_server(server);
+        return EXIT_FAILURE;
+    }
+    setup_signals();
+    while (true) {
+        int conn_fd = server_accept(server);
+        if (shutdown_flag) {
+            if (conn_fd >= 0) {
+                close(conn_fd);
+            }
+            break;
+        } else if (conn_fd < 0) {
+            continue;
+        }
+        FILE *conn = fdopen(conn_fd, "w+");
+        if (!conn) {
+            close(conn_fd);
+            continue;
+        }
+        thread_pool_enqueue(pool, handle_connection, conn);
+    }
+    destroy_thread_pool(pool);
+    destroy_server(server);
     return 0;
 }

src/server.c

@@ -0,0 +1,61 @@
+#include "server.h"
+
+#include "util.h"
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+struct _Server {
+    int socket;
+};
+
+Server *make_server(const char *text_addr, uint32_t port) {
+    struct sockaddr_in addr = {
+        .sin_family = AF_INET,
+        .sin_port = htons(port),
+    };
+    if (inet_pton(AF_INET, text_addr, &addr.sin_addr) != 1) {
+        log_error("bad IPv4 address: \"%s\"", text_addr);
+        return NULL;
+    }
+    Server *server = malloc_safe(sizeof(Server));
+    server->socket = socket(AF_INET, SOCK_STREAM, 0);
+    if (server->socket < 0) {
+        log_errno("socket");
+        free(server);
+        return NULL;
+    }
+    int on = 1;
+    if (setsockopt(server->socket, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))
+        < 0) {
+        log_errno("setsockopt SO_REUSEADDR");
+        close(server->socket);
+        free(server);
+        return NULL;
+    }
+    if (bind(server->socket, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+        log_errno("bind");
+        close(server->socket);
+        free(server);
+        return NULL;
+    }
+    if (listen(server->socket, SERVER_BACKLOG) < 0) {
+        log_errno("listen");
+        close(server->socket);
+        free(server);
+        return NULL;
+    }
+    return server;
+}
+
+void destroy_server(Server *server) {
+    close(server->socket);
+    free(server);
+}
+
+int server_accept(Server *server) {
+    return accept(server->socket, NULL, NULL);
+}

src/server.h

@@ -0,0 +1,18 @@
+#ifndef INCLUDED_SERVER_H
+#define INCLUDED_SERVER_H
+
+#include <inttypes.h>
+#include <stddef.h>
+
+constexpr int SERVER_BACKLOG = 32;
+
+typedef struct _Server Server;
+
+Server *make_server(const char *text_addr, uint32_t port);
+
+void destroy_server(Server *server);
+
+// same return value as accept(2)
+int server_accept(Server *server);
+
+#endif

src/threadpool.c

@@ -1,7 +1,9 @@
 #include "threadpool.h"
 
+#include "util.h"
+
+#include <pthread.h>
 #include <stdlib.h>
-#include <threads.h>
 
 struct thread_pool_queue {
     Task task;
@@ -10,17 +12,96 @@ struct thread_pool_queue {
 };
 
 struct _ThreadPool {
+    bool running;
     size_t nthreads;
-    thrd_t *threads;
+    sigset_t thread_sig_mask;
+    pthread_t *threads;
 
+    pthread_cond_t queue_cnd;
+    pthread_mutex_t queue_mtx;
     struct thread_pool_queue *queue;
 };
 
-ThreadPool *make_thread_pool(int parallelism) {
-    ThreadPool *pool = malloc(sizeof(ThreadPool));
-    pool->nthreads = parallelism;
+// return false if we need to stop
+static bool get_task(ThreadPool *pool, Task *task, void **task_arg) {
+    pthread_mutex_lock(&pool->queue_mtx);
+    if (!pool->running) {
+        pthread_mutex_unlock(&pool->queue_mtx);
+        return false;
+    }
+    while (true) {
+        pthread_cond_wait(&pool->queue_cnd, &pool->queue_mtx);
+        if (!pool->running) {
+            pthread_mutex_unlock(&pool->queue_mtx);
+            return false;
+        }
+        struct thread_pool_queue *ent = pool->queue;
+        if (ent) {
+            pool->queue = pool->queue->next;
+            pthread_mutex_unlock(&pool->queue_mtx);
+            *task = ent->task;
+            *task_arg = ent->arg;
+            free(ent);
+            return true;
+        }
+    }
+    abort();
 }
 
-void destroy_thread_pool(ThreadPool *pool) {}
+static void *pool_thread_function(void *arg) {
+    ThreadPool *pool = arg;
+    pthread_sigmask(SIG_SETMASK, &pool->thread_sig_mask, NULL);
+    Task task;
+    void *task_arg;
+    while (get_task(pool, &task, &task_arg)) {
+        task(task_arg);
+    }
+    return NULL;
+}
 
-void thread_pool_enqueue(Task task, void *arg) {}
+ThreadPool *make_thread_pool(size_t parallelism, sigset_t sig_mask) {
+    ThreadPool *pool = malloc_safe(sizeof(ThreadPool));
+    pthread_mutex_init(&pool->queue_mtx, NULL);
+    pthread_cond_init(&pool->queue_cnd, NULL);
+    pool->running = true;
+    pool->queue = NULL;
+    pool->nthreads = parallelism;
+    pool->thread_sig_mask = sig_mask;
+    pool->threads = malloc_safe(sizeof(pthread_t) * parallelism);
+    // create don't race with any received signals
+    sigset_t sset_full;
+    sigfillset(&sset_full);
+    sigset_t sset_save;
+    pthread_sigmask(SIG_SETMASK, &sset_full, &sset_save);
+    for (size_t i = 0; i < parallelism; ++i) {
+        pthread_create(&pool->threads[i], NULL, &pool_thread_function, pool);
+    }
+    pthread_sigmask(SIG_SETMASK, &sset_save, NULL);
+    return pool;
+}
+
+void destroy_thread_pool(ThreadPool *pool) {
+    pthread_mutex_lock(&pool->queue_mtx);
+    pool->running = false;
+    pthread_cond_broadcast(&pool->queue_cnd);
+    pthread_mutex_unlock(&pool->queue_mtx);
+    for (size_t i = 0; i < pool->nthreads; ++i) {
+        pthread_join(pool->threads[i], NULL);
+    }
+    free(pool->threads);
+    pthread_mutex_destroy(&pool->queue_mtx);
+    pthread_cond_destroy(&pool->queue_cnd);
+    free(pool);
+}
+
+void thread_pool_enqueue(ThreadPool *pool, Task task, void *arg) {
+    pthread_mutex_lock(&pool->queue_mtx);
+    struct thread_pool_queue *new =
+        malloc_safe(sizeof(struct thread_pool_queue));
+    new->task = task;
+    new->arg = arg;
+    new->next = pool->queue;
+    pool->queue = new;
+    pthread_cond_signal(&pool->queue_cnd);
+    pthread_mutex_unlock(&pool->queue_mtx);
+}

src/threadpool.h

@@ -1,13 +1,16 @@
 #ifndef INCLUDED_THREAD_POOL_H
 #define INCLUDED_THREAD_POOL_H
 
+#include <signal.h> // IWYU pragma: keep
+#include <stddef.h>
+
 typedef struct _ThreadPool ThreadPool;
 typedef void (*Task)(void *);
 
-ThreadPool *make_thread_pool(int parallelism);
+ThreadPool *make_thread_pool(size_t parallelism, sigset_t sig_mask);
 
 void destroy_thread_pool(ThreadPool *pool);
 
-void thread_pool_enqueue(Task task, void *arg);
+void thread_pool_enqueue(ThreadPool *pool, Task task, void *arg);
 
 #endif

src/util.c

@@ -1,35 +1,54 @@
 #include "util.h"
 
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
-#define DEFAULT_EXEC_NAME "httpserver"
-
-const char *EXEC_NAME = DEFAULT_EXEC_NAME;
-static bool need_free_out_of_memory_msg = false;
-NO_SANITIZE
-static const char *out_of_memory_msg =
-    DEFAULT_EXEC_NAME ": error: out of memory\n";
-
-void set_exec_name(const char *argv0) {
-    const char *slash = strrchr(argv0, '/');
-    if (!slash) {
-        EXEC_NAME = argv0;
-    } else {
-        EXEC_NAME = slash + 1;
-    }
-    if (need_free_out_of_memory_msg) {
-        free((char *) out_of_memory_msg);
+void *realloc_safe(void *oldptr, size_t size) {
+    static const char OOM_MSG[] = "fatal: out of memory\n";
+    void *ptr = realloc(oldptr, size);
+    if (size && !ptr) {
+        fwrite(OOM_MSG, 1, sizeof(OOM_MSG) - 1, stderr);
+        abort();
     }
+    return ptr;
 }
 
-void log_error(const char *fmt, ...) {
-    fprintf(stderr, "%s: error: ", EXEC_NAME);
+void *malloc_safe(size_t size) {
+    return realloc_safe(NULL, size);
+}
+
+// asprintf is not POSIX
+int alloc_sprintf(char *restrict *restrict out, const char *restrict fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    va_list args2;
+    va_copy(args2, args);
+    int need = vsnprintf(NULL, 0, fmt, args2);
+    va_end(args2);
+    *out = realloc_safe(*out, need + 1);
+    int written = vsnprintf(*out, need + 1, fmt, args);
+    va_end(args);
+    return written;
+}
+
+void log_error(const char *restrict fmt, ...) {
+    time_t cur_time = time(NULL);
+    struct tm tm;
+    localtime_r(&cur_time, &tm);
+    char time_str[32];
+    strftime(time_str, sizeof(time_str), "%c", &tm);
+    fprintf(stderr, "[%s] error: ", time_str);
     va_list args;
     va_start(args, fmt);
     vfprintf(stderr, fmt, args);
     va_end(args);
     fputc('\n', stderr);
 }
+
+void log_errno(const char *detail) {
+    log_error("%s: %s", detail, strerror(errno));
+}

src/util.h

@@ -1,23 +1,23 @@
 #ifndef INCLUDED_UTIL_H
 #define INCLUDED_UTIL_H
 
+#include <stddef.h>
+
 #if __has_attribute(format)
 #    define PRINTF_LIKE(i, j) __attribute__((format(printf, i, j)))
 #else
 #    define PRINTF_LIKE(i, j)
 #endif
 
-#if __has_attribute(no_sanitize_address)
-#    define NO_SANITIZE __attribute__((no_sanitize_address))
-#else
-#    define NO_SANITIZE
-#endif
+void *realloc_safe(void *oldptr, size_t size);
+void *malloc_safe(size_t size);
 
-extern const char *EXEC_NAME;
-
-void set_exec_name(const char *argv0);
+// asprintf is not POSIX
+PRINTF_LIKE(2, 3)
+int alloc_sprintf(char *restrict *restrict out, const char *restrict fmt, ...);
 
 PRINTF_LIKE(1, 2)
-void log_error(const char *fmt, ...);
+void log_error(const char *restrict fmt, ...);
+void log_errno(const char *detail);
 
 #endif