Add basic tools

meson.build

@@ -26,6 +26,11 @@ c_compiler = meson.get_compiler('c')
 # We require a compiler that supports the GNU C dialect.
 assert(c_compiler.has_define('__GNUC__'))
 
+if get_option('tools_only')
+    subdir('tools')
+    subdir_done()
+endif
+
 add_project_arguments(
     '-Wno-unused',
     '-Wno-unused-parameter',

meson.options

@@ -5,6 +5,13 @@ option(
     description: 'Only install headers',
 )
 
+option(
+    'tools_only',
+    type: 'boolean',
+    value: false,
+    description: 'Only build userspace tools',
+)
+
 option(
     'config_path',
     type: 'string',

toolchain/aarch64.cross-file

@@ -0,0 +1,19 @@
+[binaries]
+c = 'clang'
+cpp = 'clang++'
+ar = 'llvm-ar'
+strip = 'llvm-strip'
+objcopy = 'llvm-objcopy'
+ld = 'ld.lld'
+
+[built-in options]
+c_args = ['-target', 'aarch64-unknown-none']
+cpp_args = ['-target', 'aarch64-unknown-none']
+c_link_args = ['--target=aarch64-unknown-linux-gnu', '-fuse-ld=lld']
+cpp_link_args = ['--target=aarch64-unknown-linux-gnu', '-fuse-ld=lld']
+
+[host_machine]
+system = 'linux'
+cpu_family = 'aarch64'
+cpu = 'aarch64'
+endian = 'little'

toolchain/riscv64.cross-file

@@ -0,0 +1,19 @@
+[binaries]
+c = 'clang'
+cpp = 'clang++'
+ar = 'llvm-ar'
+strip = 'llvm-strip'
+objcopy = 'llvm-objcopy'
+ld = 'ld.lld'
+
+[built-in options]
+c_args = ['-target', 'riscv64-unknown-none']
+cpp_args = ['-target', 'riscv64-unknown-none']
+c_link_args = ['--target=riscv64-unknown-linux-gnu', '-fuse-ld=lld']
+cpp_link_args = ['--target=riscv64-unknown-linux-gnu', '-fuse-ld=lld']
+
+[host_machine]
+system = 'linux'
+cpu_family = 'riscv64'
+cpu = 'riscv64'
+endian = 'little'

toolchain/x86_64.cross-file

@@ -0,0 +1,19 @@
+[binaries]
+c = 'clang'
+cpp = 'clang++'
+ar = 'llvm-ar'
+strip = 'llvm-strip'
+objcopy = 'llvm-objcopy'
+ld = 'ld.lld'
+
+[built-in options]
+c_args = ['-target', 'x86_64-unknown-none']
+cpp_args = ['-target', 'x86_64-unknown-none']
+c_link_args = ['--target=x86_64-unknown-linux-gnu', '-fuse-ld=lld']
+cpp_link_args = ['--target=x86_64-unknown-linux-gnu', '-fuse-ld=lld']
+
+[host_machine]
+system = 'linux'
+cpu_family = 'x86_64'
+cpu = 'x86_64'
+endian = 'little'

tools/console.c

@@ -0,0 +1,42 @@
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+int main(int argc, char** argv) {
+    if (argc < 3) {
+        fprintf(stderr, "usage: %s <tty> <command> [args...]\n", argv[0]);
+        return 2;
+    }
+
+    const char* tty = argv[1];
+
+    if (setsid() < 0 && getpid() != getsid(0)) {
+        perror("setsid");
+        return 1;
+    }
+
+    int fd = open(tty, O_RDWR);
+    if (fd < 0) {
+        perror(tty);
+        return 1;
+    }
+
+    if (ioctl(fd, TIOCSCTTY, 0) != 0)
+        perror("TIOCSCTTY");
+
+    if (dup2(fd, STDIN_FILENO) < 0 || dup2(fd, STDOUT_FILENO) < 0 || dup2(fd, STDERR_FILENO) < 0) {
+        perror("dup2");
+        return 1;
+    }
+
+    if (fd > STDERR_FILENO)
+        close(fd);
+
+    execvp(argv[2], &argv[2]);
+    perror(argv[2]);
+    return 1;
+}

tools/devd.c

@@ -0,0 +1,180 @@
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#define DEVCTL_PATH "/dev/devctl"
+#define SOCKET_PATH "/var/run/devd.pipe"
+#define MAX_CLIENTS 32
+#define DEVCTL_BUF  4096
+#define LINE_BUF    1024
+
+static int clients[MAX_CLIENTS];
+static int nclients = 0;
+
+// Accumulates a partial line read from /dev/devctl across reads.
+static char line[LINE_BUF];
+static size_t line_len = 0;
+
+static void add_client(int fd) {
+    if (nclients >= MAX_CLIENTS) {
+        close(fd);
+        return;
+    }
+    clients[nclients++] = fd;
+}
+
+static void remove_client(int idx) {
+    close(clients[idx]);
+    clients[idx] = clients[--nclients];
+}
+
+// Broadcast a single notification line (including its trailing newline).
+static void broadcast(const char* buf, size_t len) {
+    for (int i = 0; i < nclients;) {
+        ssize_t off = 0;
+        int dead = 0;
+        while (off < (ssize_t)len) {
+            ssize_t n = write(clients[i], buf + off, len - off);
+            if (n < 0) {
+                if (errno == EINTR)
+                    continue;
+                dead = 1;
+                break;
+            }
+            off += n;
+        }
+        if (dead)
+            remove_client(i);
+        else
+            i++;
+    }
+}
+
+// Feed raw bytes from /dev/devctl.
+static void feed(const char* data, size_t len) {
+    for (size_t i = 0; i < len; i++) {
+        char c = data[i];
+        if (line_len < sizeof(line) - 1)
+            line[line_len++] = c;
+        if (c == '\n') {
+            broadcast(line, line_len);
+            line_len = 0;
+        }
+    }
+    // Drop an overlong line that never terminated, to avoid wedging.
+    if (line_len >= sizeof(line) - 1)
+        line_len = 0;
+}
+
+static int open_devctl(void) {
+    int fd = open(DEVCTL_PATH, O_RDONLY | O_CLOEXEC);
+    if (fd < 0)
+        perror("devd: open " DEVCTL_PATH);
+    return fd;
+}
+
+static int make_listener(void) {
+    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (fd < 0) {
+        perror("devd: socket");
+        return -1;
+    }
+
+    struct sockaddr_un addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    strncpy(addr.sun_path, SOCKET_PATH, sizeof(addr.sun_path) - 1);
+
+    unlink(SOCKET_PATH);
+    if (bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
+        perror("devd: bind " SOCKET_PATH);
+        close(fd);
+        return -1;
+    }
+    chmod(SOCKET_PATH, 0666);
+
+    if (listen(fd, 8) < 0) {
+        perror("devd: listen");
+        close(fd);
+        return -1;
+    }
+    return fd;
+}
+
+int main(void) {
+    // A client going away must not kill us.
+    signal(SIGPIPE, SIG_IGN);
+
+    int devctl = open_devctl();
+    if (devctl < 0)
+        return 1;
+
+    int listener = make_listener();
+    if (listener < 0)
+        return 1;
+
+    printf("devd: listening on %s, forwarding from %s\n", SOCKET_PATH, DEVCTL_PATH);
+    fflush(stdout);
+
+    for (;;) {
+        struct pollfd pfds[2 + MAX_CLIENTS];
+        pfds[0].fd = devctl;
+        pfds[0].events = POLLIN;
+        pfds[1].fd = listener;
+        pfds[1].events = POLLIN;
+        for (int i = 0; i < nclients; i++) {
+            pfds[2 + i].fd = clients[i];
+            pfds[2 + i].events = 0; // Only watch for hangup.
+        }
+
+        int n = poll(pfds, 2 + nclients, -1);
+        if (n < 0) {
+            if (errno == EINTR)
+                continue;
+            perror("devd: poll");
+            break;
+        }
+
+        // New notifications from the kernel.
+        if (pfds[0].revents & POLLIN) {
+            char buf[DEVCTL_BUF];
+            ssize_t r = read(devctl, buf, sizeof(buf));
+            if (r > 0) {
+                feed(buf, (size_t)r);
+            } else if (r == 0 || (r < 0 && errno != EINTR && errno != EAGAIN)) {
+                fprintf(stderr, "devd: %s closed, exiting\n", DEVCTL_PATH);
+                break;
+            }
+        }
+
+        // New client connections.
+        if (pfds[1].revents & POLLIN) {
+            int c = accept(listener, NULL, NULL);
+            if (c >= 0) {
+                fcntl(c, F_SETFD, FD_CLOEXEC);
+                add_client(c);
+            }
+        }
+
+        // Reap clients that hung up.
+        for (int i = nclients - 1; i >= 0; i--) {
+            if (pfds[2 + i].revents & (POLLHUP | POLLERR | POLLNVAL))
+                remove_client(i);
+        }
+    }
+
+    close(devctl);
+    close(listener);
+    unlink(SOCKET_PATH);
+    return 1;
+}

tools/insertmod.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/module.h>
+
+int main(int argc, char** argv) {
+    if (argc < 2) {
+        fprintf(stderr, "usage: %s <module-path> [cmdline]\n", argv[0]);
+        return 2;
+    }
+
+    const char* path = argv[1];
+    const char* cmdline = argc >= 3 ? argv[2] : NULL;
+
+    if (insertmod(path, cmdline) != 0) {
+        perror("insertmod");
+        return 1;
+    }
+
+    return 0;
+}

tools/kmsg.c

@@ -0,0 +1,283 @@
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+constexpr size_t LINE_MAX_LEN = 8192;
+
+static const char* const level_names[] = {
+    "emerg",
+    "alert",
+    "crit",
+    "err",
+    "warn",
+    "notice",
+    "info",
+    "debug",
+};
+
+#define COLOR_RESET  "\033[0m"
+#define COLOR_TIME   "\033[32m"
+#define COLOR_SUBSYS "\033[33m"
+
+static const char* const level_colors[] = {
+    "\033[7;31m",
+    "\033[7;31m",
+    "\033[1;31m",
+    "\033[31m",
+    "\033[1m",
+    "",
+    "",
+    "",
+};
+
+struct options {
+    bool follow;
+    bool raw;
+    bool decode;
+    bool color;
+    unsigned int level_mask;
+};
+
+static int hex_value(char c) {
+    if (c >= '0' && c <= '9')
+        return c - '0';
+    if (c >= 'a' && c <= 'f')
+        return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F')
+        return c - 'A' + 10;
+    return -1;
+}
+
+static size_t unescape(const char* in, size_t len, char* out) {
+    size_t n = 0;
+    for (size_t i = 0; i < len; i++) {
+        if (in[i] == '\\' && i + 3 < len && in[i + 1] == 'x') {
+            const int hi = hex_value(in[i + 2]);
+            const int lo = hex_value(in[i + 3]);
+            if (hi >= 0 && lo >= 0) {
+                out[n++] = (char)(hi << 4 | lo);
+                i += 3;
+                continue;
+            }
+        }
+        out[n++] = in[i];
+    }
+    return n;
+}
+
+static const char* find_caller(char* header) {
+    char* save;
+    for (char* field = strtok_r(header, ",", &save); field; field = strtok_r(nullptr, ",", &save)) {
+        if (!strncmp(field, "caller=", 7))
+            return field + 7;
+    }
+    return nullptr;
+}
+
+static size_t subsystem_len(const char* text, size_t len) {
+    for (size_t i = 0; i + 1 < len; i++) {
+        if (text[i] == ':' && (text[i + 1] == ' ' || text[i + 1] == '\t'))
+            return i + 1;
+    }
+    return 0;
+}
+
+static void print_record(const struct options* opts, char* record, size_t len) {
+    if (opts->raw) {
+        printf("%.*s\n", (int)len, record);
+        return;
+    }
+
+    char* msg = memchr(record, ';', len);
+    if (!msg)
+        return;
+    *msg++ = '\0';
+
+    unsigned int prio;
+    uint64_t seq;
+    uint64_t usec;
+    if (sscanf(record, "%u,%" SCNu64 ",%" SCNu64, &prio, &seq, &usec) != 3)
+        return;
+
+    const unsigned int level = prio & 7;
+    if (!(opts->level_mask & (1u << level)))
+        return;
+
+    const char* caller = find_caller(record);
+
+    static char text[LINE_MAX_LEN];
+    const size_t text_len = unescape(msg, len - (size_t)(msg - record), text);
+
+    if (opts->decode)
+        printf("%-6s: ", level_names[level]);
+
+    if (opts->color)
+        printf(COLOR_TIME);
+    printf("[%5" PRIu64 ".%06" PRIu64 "]", usec / 1'000'000, usec % 1'000'000);
+    if (opts->color)
+        printf(COLOR_RESET);
+    putchar(' ');
+
+    if (caller)
+        printf("[%6s] ", caller);
+
+    const char* text_pos = text;
+    size_t remaining = text_len;
+    const size_t subsys = subsystem_len(text, text_len);
+    if (subsys) {
+        if (opts->color)
+            printf(COLOR_SUBSYS "%.*s" COLOR_RESET, (int)subsys, text);
+        else
+            printf("%.*s", (int)subsys, text);
+        text_pos += subsys;
+        remaining -= subsys;
+    }
+
+    const char* color = opts->color ? level_colors[level] : "";
+    if (*color)
+        printf("%s%.*s" COLOR_RESET "\n", color, (int)remaining, text_pos);
+    else
+        printf("%.*s\n", (int)remaining, text_pos);
+}
+
+static int parse_levels(const char* list, unsigned int* mask) {
+    char* copy = strdup(list);
+    if (!copy)
+        return -1;
+
+    *mask = 0;
+    char* save;
+    for (char* tok = strtok_r(copy, ",", &save); tok; tok = strtok_r(nullptr, ",", &save)) {
+        bool found = false;
+        for (unsigned int i = 0; i < 8; i++) {
+            if (!strcmp(tok, level_names[i])) {
+                *mask |= 1u << i;
+                found = true;
+                break;
+            }
+        }
+        if (!found) {
+            fprintf(stderr, "kmsg: unknown level '%s'\n", tok);
+            free(copy);
+            return -1;
+        }
+    }
+    free(copy);
+    return 0;
+}
+
+static void usage(const char* prog) {
+    fprintf(
+        stderr,
+        "usage: %s [-w] [-r] [-x] [-l level[,level...]] [--color=auto|always|never]\n"
+        "  -w, --follow     wait for new messages\n"
+        "  -r, --raw        print raw /dev/kmsg records\n"
+        "  -x, --decode     show the log level of each message\n"
+        "  -l, --level      only show the given levels (emerg,alert,crit,err,warn,notice,info,debug)\n"
+        "  -L, --color      colorize output (auto, always, never)\n",
+        prog
+    );
+}
+
+int main(int argc, char** argv) {
+    struct options opts = {
+        .level_mask = 0xFF,
+    };
+    int color_mode = -1;
+
+    static const struct option long_opts[] = {
+        {"follow", no_argument, nullptr, 'w'},
+        {"raw", no_argument, nullptr, 'r'},
+        {"decode", no_argument, nullptr, 'x'},
+        {"level", required_argument, nullptr, 'l'},
+        {"color", optional_argument, nullptr, 'L'},
+        {"help", no_argument, nullptr, 'h'},
+        {},
+    };
+
+    int c;
+    while ((c = getopt_long(argc, argv, "wrxl:L::h", long_opts, nullptr)) != -1) {
+        switch (c) {
+        case 'w':
+            opts.follow = true;
+            break;
+        case 'r':
+            opts.raw = true;
+            break;
+        case 'x':
+            opts.decode = true;
+            break;
+        case 'l':
+            if (parse_levels(optarg, &opts.level_mask))
+                return 1;
+            break;
+        case 'L':
+            if (!optarg || !strcmp(optarg, "always"))
+                color_mode = 1;
+            else if (!strcmp(optarg, "never"))
+                color_mode = 0;
+            else if (!strcmp(optarg, "auto"))
+                color_mode = -1;
+            else {
+                usage(argv[0]);
+                return 1;
+            }
+            break;
+        case 'h':
+            usage(argv[0]);
+            return 0;
+        default:
+            usage(argv[0]);
+            return 1;
+        }
+    }
+
+    opts.color = color_mode < 0 ? isatty(STDOUT_FILENO) : color_mode;
+
+    const int fd = open("/dev/kmsg", O_RDONLY | (opts.follow ? 0 : O_NONBLOCK));
+    if (fd < 0) {
+        perror("kmsg: /dev/kmsg");
+        return 1;
+    }
+
+    static char record[LINE_MAX_LEN];
+    while (true) {
+        const ssize_t n = read(fd, record, sizeof(record) - 1);
+        if (n < 0) {
+            if (errno == EINTR)
+                continue;
+            if (errno == EPIPE)
+                continue;
+            if (errno == EAGAIN)
+                break;
+            perror("kmsg: read");
+            close(fd);
+            return 1;
+        }
+        if (n == 0)
+            break;
+        record[n] = '\0';
+        for (char* line = record; line < record + n;) {
+            char* end = memchr(line, '\n', (size_t)(record + n - line));
+            if (!end)
+                end = record + n;
+            *end = '\0';
+            if (*line != ' ')
+                print_record(&opts, line, (size_t)(end - line));
+            line = end + 1;
+        }
+        if (opts.follow)
+            fflush(stdout);
+    }
+
+    close(fd);
+    return 0;
+}

tools/meson.build

@@ -0,0 +1,6 @@
+executable('console', 'console.c', install: true)
+executable('devd', 'devd.c', install: true)
+executable('insertmod', 'insertmod.c', install: true)
+executable('kmsg', 'kmsg.c', install: true)
+executable('mount', 'mount.c', install: true)
+executable('umount', 'umount.c', install: true)

tools/mount.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <string.h>
+#include <sys/mount.h>
+
+int main(int argc, char** argv) {
+    if (argc < 3) {
+        fprintf(stderr, "usage: %s <fstype> <target> [source]\n", argv[0]);
+        return 2;
+    }
+
+    const char* fstype = argv[1];
+    const char* target = argv[2];
+    const char* source = argc >= 4 ? argv[3] : NULL;
+
+    if (mount(fstype, target, 0, (void*)source) != 0) {
+        perror("mount");
+        return 1;
+    }
+
+    return 0;
+}

tools/umount.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <sys/mount.h>
+
+int main(int argc, char** argv) {
+    if (argc < 2) {
+        fprintf(stderr, "usage: %s <target>\n", argv[0]);
+        return 2;
+    }
+
+    if (unmount(argv[1], 0) != 0) {
+        perror("umount");
+        return 1;
+    }
+
+    return 0;
+}