X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Fdinit-log.cc;h=43062f0f15a400ca938c7d188be6b9f9d5dcc28b;hb=100650949c81204d8d52002e028aa8858a406bce;hp=8e031e7fa57b378e4ab04f71a12b91d87268f80d;hpb=20a52bc5344dd7b2fe6e3d40a050746fc49290c4;p=oweals%2Fdinit.git

diff --git a/src/dinit-log.cc b/src/dinit-log.cc
index 8e031e7..43062f0 100644
--- a/src/dinit-log.cc
+++ b/src/dinit-log.cc
@@ -1,68 +1,433 @@
 #include <iostream>
+#include <algorithm>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/syslog.h>
+#include <sys/uio.h>
+
+#include "dasynq.h"
+
+#include "service.h"
 #include "dinit-log.h"
+#include "cpbuffer.h"
+
+extern EventLoop_t eventLoop;
+
+static bool log_current_line[2];  // Whether the current line is being logged (for console, main log)
+LogLevel log_level[2] = { LogLevel::WARN, LogLevel::WARN };
+
+static ServiceSet *service_set = nullptr;  // Reference to service set
+
+namespace {
+class BufferedLogStream : public EventLoop_t::FdWatcher
+{
+    private:
+
+    // Outgoing:
+    bool partway = false;     // if we are partway throught output of a log message
+    bool discarded = false;   // if we have discarded a message
+    bool release = true;      // if we should inhibit output and release console
+
+    // A "special message" is not stored in the circular buffer; instead
+    // it is delivered from an external buffer not managed by BufferedLogger.
+    bool special = false;      // currently outputting special message?
+    char *special_buf; // buffer containing special message
+    int msg_index;     // index into special message
+
+    CPBuffer<4096> log_buffer;
+    
+    public:
+    
+    // Incoming:
+    int current_index = 0;    // current/next incoming message index
+
+    int fd = -1;
+
+    void init(int fd)
+    {
+        this->fd = fd;
+        release = false;
+    }
+    
+    Rearm gotEvent(EventLoop_t *loop, int fd, int flags) noexcept override;
+
+    // Check whether the console can be released.
+    void flushForRelease();
+    void release_console();
+    bool is_release_set() { return release; }
+    
+    // Commit a log message
+    void commit_msg()
+    {
+        bool was_first = current_index == 0;
+        current_index = log_buffer.get_length();
+        if (was_first && ! release) {
+            setEnabled(&eventLoop, true);
+        }
+    }
+    
+    void rollback_msg()
+    {
+        log_buffer.trim_to(current_index);
+    }
+    
+    int get_free()
+    {
+        return log_buffer.get_free();
+    }
+    
+    void append(const char *s, size_t len)
+    {
+        log_buffer.append(s, len);
+    }
+};
+}
+
+// Two log streams:
+// (One for main log, one for console)
+static BufferedLogStream log_stream[2];
+
+constexpr static int DLOG_MAIN = 0; // main log facility
+constexpr static int DLOG_CONS = 1; // console
+
+void BufferedLogStream::release_console()
+{
+    if (release) {
+        int flags = fcntl(1, F_GETFL, 0);
+        fcntl(1, F_SETFL, flags & ~O_NONBLOCK);
+        service_set->pullConsoleQueue();
+    }
+}
+
+void BufferedLogStream::flushForRelease()
+{
+    release = true;
+    
+    // Try to flush any messages that are currently buffered. (Console is non-blocking
+    // so it will fail gracefully).
+    if (gotEvent(&eventLoop, fd, OUT_EVENTS) == Rearm::DISARM) {
+        // Console has already been released at this point.
+        setEnabled(&eventLoop, false);
+    }
+    // gotEvent didn't want to disarm, so must be partway through a message; will
+    // release when it's finished.
+}
+
+Rearm BufferedLogStream::gotEvent(EventLoop_t *loop, int fd, int flags) noexcept
+{
+    auto &log_stream = *this;
+    
+    if ((! partway) && log_stream.special) {
+        char * start = log_stream.special_buf + log_stream.msg_index;
+        char * end = std::find(log_stream.special_buf + log_stream.msg_index, (char *)nullptr, '\n');
+        int r = write(fd, start, end - start + 1);
+        if (r >= 0) {
+            if (start + r > end) {
+                // All written: go on to next message in queue
+                log_stream.special = false;
+                log_stream.partway = false;
+                log_stream.msg_index = 0;
+                
+                if (release) {
+                    release_console();
+                    return Rearm::DISARM;
+                }
+            }
+            else {
+                log_stream.msg_index += r;
+                return Rearm::REARM;
+            }
+        }
+        else if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
+            return Rearm::REMOVE;
+        }
+        return Rearm::REARM;
+    }
+    else {
+        // Writing from the regular circular buffer
+        
+        // TODO issue special message if we have discarded a log message
+        
+        if (current_index == 0) {
+            release_console();
+            return Rearm::DISARM;
+        }
+        
+        // We try to find a complete line (terminated by '\n') in the buffer, and write it
+        // out. Since it may span the circular buffer end, it may consist of two distinct spans,
+        // and so we use writev to write them atomically.
+        
+        struct iovec logiov[2];
+        
+        char *ptr = log_buffer.get_ptr(0);
+        int len = log_buffer.get_contiguous_length(ptr);
+        char *creptr = ptr + len;  // contiguous region end
+        char *eptr = std::find(ptr, creptr, '\n');
+        
+        bool will_complete = false;  // will complete this message?
+        if (eptr != creptr) {
+            eptr++;  // include '\n'
+            will_complete = true;
+        }
+
+        len = eptr - ptr;
+        
+        logiov[0].iov_base = ptr;
+        logiov[0].iov_len = len;
+        int iovs_to_write = 1;
+        
+        // Do we need the second span?
+        if (! will_complete && len != log_buffer.get_length()) {
+            ptr = log_buffer.get_buf_base();
+            creptr = static_cast<char *>(logiov[1].iov_base) + log_buffer.get_length() - len;
+            eptr = std::find(ptr, creptr, '\n');
+            if (eptr != creptr) {
+                eptr++; // include '\n'
+                // It should not ever be the case that we do not now have a complete message
+                will_complete = true;
+            }
+            logiov[1].iov_base = ptr;
+            logiov[1].iov_len = eptr - ptr;
+            len += logiov[1].iov_len;
+            iovs_to_write = 2;
+        }
+        
+        ssize_t r = writev(fd, logiov, iovs_to_write);
+
+        if (r >= 0) {
+            bool complete = (r == len) && will_complete;
+            log_stream.log_buffer.consume(len);
+            log_stream.partway = ! complete;
+            if (complete) {
+                log_stream.current_index -= len;
+                if (log_stream.current_index == 0 || release) {
+                    // No more messages buffered / stop logging to console:
+                    release_console();
+                    return Rearm::DISARM;
+                }
+            }
+        }
+        else if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
+            return Rearm::REMOVE;
+        }
+    }
+    
+    // We've written something by the time we get here. We could fall through to below, but
+    // let's give other events a chance to be processed by returning now.
+    return Rearm::REARM;
+}
+
+// Initialise the logging subsystem
+// Potentially throws std::bad_alloc or std::system_error
+void init_log(ServiceSet *sset)
+{
+    service_set = sset;
+    log_stream[DLOG_CONS].registerWith(&eventLoop, STDOUT_FILENO, OUT_EVENTS); // TODO register in disabled state
+    enable_console_log(true);
+}
+
+// Set up the main log to output to the given file descriptor.
+// Potentially throws std::bad_alloc or std::system_error
+void setup_main_log(int fd)
+{
+    log_stream[DLOG_MAIN].init(fd);
+    log_stream[DLOG_MAIN].registerWith(&eventLoop, fd, OUT_EVENTS);
+}
+
+bool is_log_flushed() noexcept
+{
+    return log_stream[DLOG_CONS].current_index == 0;
+}
 
-LogLevel log_level = LogLevel::WARN;
-bool log_to_console = true;    // whether we should output log messages to console
-bool log_current_line;
+// Enable or disable console logging. If disabled, console logging will be disabled on the
+// completion of output of the current message (if any), at which point the first service record
+// queued in the service set will acquire the console.
+void enable_console_log(bool enable) noexcept
+{
+    bool log_to_console = ! log_stream[DLOG_CONS].is_release_set();
+    if (enable && ! log_to_console) {
+        // Console is fd 1 - stdout
+        // Set non-blocking IO:
+        int flags = fcntl(1, F_GETFL, 0);
+        fcntl(1, F_SETFL, flags | O_NONBLOCK);
+        // Activate watcher:
+        log_stream[DLOG_CONS].init(STDOUT_FILENO);
+        log_stream[DLOG_CONS].setEnabled(&eventLoop, true);
+    }
+    else if (! enable && log_to_console) {
+        log_stream[DLOG_CONS].flushForRelease();
+    }
+}
+
+
+// Variadic method to calculate the sum of string lengths:
+static int sum_length(const char *arg) noexcept
+{
+    return std::strlen(arg);
+}
+
+template <typename ... T> static int sum_length(const char * first, T ... args) noexcept
+{
+    return sum_length(first) + sum_length(args...);
+}
+
+// Variadic method to append strings to a buffer:
+static void append(BufferedLogStream &buf, const char *s)
+{
+    buf.append(s, std::strlen(s));
+}
+
+template <typename ... T> static void append(BufferedLogStream &buf, const char *u, T ... t)
+{
+    append(buf, u);
+    append(buf, t...);
+}
+
+static int log_level_to_syslog_level(LogLevel l)
+{
+    switch (l) {
+    case LogLevel::DEBUG:
+        return LOG_DEBUG;
+    case LogLevel::INFO:
+        return LOG_INFO;
+    case LogLevel::WARN:
+        return LOG_WARNING;
+    case LogLevel::ERROR:
+        return LOG_ERR;
+    default: ;
+    }
+    
+    return LOG_CRIT;
+}
+
+// Variadic method to log a sequence of strings as a single message to a particular facility:
+template <typename ... T> static void push_to_log(int idx, T ... args) noexcept
+{
+    if (! log_current_line[idx]) return;
+    int amount = sum_length(args...);
+    if (log_stream[idx].get_free() >= amount) {
+        append(log_stream[idx], args...);
+        log_stream[idx].commit_msg();
+    }
+    else {
+        // TODO mark a discarded message
+    }
+}
+
+// Variadic method to potentially log a sequence of strings as a single message with the given log level:
+template <typename ... T> static void do_log(LogLevel lvl, T ... args) noexcept
+{
+    log_current_line[DLOG_CONS] = lvl >= log_level[DLOG_CONS];
+    log_current_line[DLOG_MAIN] = lvl >= log_level[DLOG_MAIN];
+    push_to_log(DLOG_CONS, args...);
+    
+    if (log_current_line[DLOG_MAIN]) {
+        char svcbuf[10];
+        snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | log_level_to_syslog_level(lvl));
+        
+        push_to_log(DLOG_MAIN, svcbuf, args...);
+    }
+}
+
+template <typename ... T> static void do_log_cons(T ... args) noexcept
+{
+    log_current_line[DLOG_CONS] = true;
+    log_current_line[DLOG_MAIN] = false;
+    push_to_log(DLOG_CONS, args...);
+}
+
+// Log to the main facility at NOTICE level
+template <typename ... T> static void do_log_main(T ... args) noexcept
+{
+    log_current_line[DLOG_CONS] = false;
+    log_current_line[DLOG_MAIN] = true;
+    
+    char svcbuf[10];
+    snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | LOG_NOTICE);
+    
+    push_to_log(DLOG_MAIN, svcbuf, args...);
+}
 
-// Log a message
+// Log a message. A newline will be appended.
 void log(LogLevel lvl, const char *msg) noexcept
 {
-    if (lvl >= log_level) {
-        if (log_to_console) {
-            std::cout << "dinit: " << msg << std::endl;
+    do_log(lvl, "dinit: ", msg, "\n");
+}
+
+// Log part of a message. A series of calls to do_log_part must be followed by a call to do_log_commit.
+template <typename T> static void do_log_part(int idx, T arg) noexcept
+{
+    if (log_current_line[idx]) {
+        int amount = sum_length(arg);
+        if (log_stream[idx].get_free() >= amount) {
+            append(log_stream[idx], arg);
+        }
+        else {
+            log_stream[idx].rollback_msg();
+            log_current_line[idx] = false;
+            // TODO mark discarded message
         }
     }
 }
 
+// Commit a message that was issued as a series of parts (via do_log_part).
+static void do_log_commit(int idx) noexcept
+{
+    if (log_current_line[idx]) {
+        log_stream[idx].commit_msg();
+    }
+}
+
 // Log a multi-part message beginning
 void logMsgBegin(LogLevel lvl, const char *msg) noexcept
 {
-    log_current_line = lvl >= log_level;
-    if (log_current_line) {
-        if (log_to_console) {
-            std::cout << "dinit: " << msg;
-        }
+    log_current_line[DLOG_CONS] = lvl >= log_level[DLOG_CONS];
+    log_current_line[DLOG_MAIN] = lvl >= log_level[DLOG_MAIN];
+
+    if (log_current_line[DLOG_MAIN]) {
+        char svcbuf[10];
+        snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | log_level_to_syslog_level(lvl));
+        do_log_part(DLOG_MAIN, svcbuf);
+    }
+
+    for (int i = 0; i < 2; i++) {
+        do_log_part(i, "dinit: ");
+        do_log_part(i, msg);
     }
 }
 
 // Continue a multi-part log message
 void logMsgPart(const char *msg) noexcept
 {
-    if (log_current_line) {
-        if (log_to_console) {
-            std::cout << msg;
-        }
-    }
+    do_log_part(DLOG_CONS, msg);
+    do_log_part(DLOG_MAIN, msg);
 }
 
 // Complete a multi-part log message
 void logMsgEnd(const char *msg) noexcept
 {
-    if (log_current_line) {
-        if (log_to_console) {
-            std::cout << msg << std::endl;
-        }
+    for (int i = 0; i < 2; i++) {
+        do_log_part(i, msg);
+        do_log_part(i, "\n");
+        do_log_commit(i);
     }
 }
 
 void logServiceStarted(const char *service_name) noexcept
 {
-    if (log_to_console) {
-        std::cout << "[  OK  ] " << service_name << std::endl;
-    }
+    do_log_cons("[  OK  ] ", service_name, "\n");
+    do_log_main("dinit: service ", service_name, " started.\n");
 }
 
 void logServiceFailed(const char *service_name) noexcept
 {
-    if (log_to_console) {
-        std::cout << "[FAILED] " << service_name << std::endl;
-    }
+    do_log_cons("[FAILED] ", service_name, "\n");
+    do_log_main("dinit: service ", service_name, " failed to start.\n");
 }
 
 void logServiceStopped(const char *service_name) noexcept
 {
-    if (log_to_console) {
-        std::cout << "[STOPPED] " << service_name << std::endl;
-    }
+    do_log_cons("[STOPPD] ", service_name, "\n");
+    do_log_main("dinit: service ", service_name, " stopped.\n");
 }