log_file.c

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#include <kernel/log/log_file.h>
 
#include <kernel/fs/file.h>
#include <kernel/fs/sysfs.h>
#include <kernel/log/log.h>
#include <kernel/log/log_screen.h>
#include <kernel/log/panic.h>
#include <kernel/utils/ring.h>
 
#include <stdlib.h>
 
static lock_t lock = LOCK_CREATE;
 
static char workingBuffer[LOG_FILE_MAX_BUFFER] = {0};
static char buffer[LOG_FILE_MAX_BUFFER] = {0};
static ring_t ring = RING_CREATE(buffer, sizeof(buffer));
static dentry_t* file = NULL;
 
static uint64_t log_file_op_read(file_t* file, void* buffer, uint64_t count, uint64_t* offset)
{
    (void)file; // Unused
 
    LOCK_SCOPE(&lock);
    uint64_t result = ring_read_at(&ring, *offset, buffer, count);
    *offset += result;
    return result;
}
 
static uint64_t log_file_op_write(file_t* file, const void* buffer, uint64_t count, uint64_t* offset)
{
    (void)file; // Unused
 
    if (count == 0 || buffer == NULL || offset == NULL)
    {
        return 0;
    }
 
    if (count > MAX_PATH)
    {
        errno = EINVAL;
        return ERR;
    }
 
    char string[MAX_PATH];
    memcpy(string, buffer, count);
    string[count] = '\0';
 
    LOG_USER("%s", string);
    *offset += count;
    return count;
}
 
static file_ops_t logFileOps = {
    .read = log_file_op_read,
    .write = log_file_op_write,
};
 
void log_file_expose(void)
{
    file = sysfs_file_new(NULL, "klog", NULL, &logFileOps, NULL);
    if (file == NULL)
    {
        panic(NULL, "failed to create klog sysfs file");
    }
}
 
static void log_file_advance_fake_cursor(char chr, uint64_t* lineLength, uint64_t* lineCount)
{
    if (chr == '\n')
    {
        (*lineCount)++;
        *lineLength = 0;
    }
    else if (*lineLength >= log_screen_get_width())
    {
        (*lineCount)++;
        *lineLength = SCREEN_WRAP_INDENT;
    }
    else
    {
        (*lineLength)++;
    }
}
 
void log_file_flush_to_screen(void)
{
    LOCK_SCOPE(&lock);
    log_screen_clear();
 
    uint64_t lineLength = 0;
    uint64_t lineCount = 0;
    for (uint64_t i = 0; i < ring_data_length(&ring); i++)
    {
        uint8_t chr;
        ring_get_byte(&ring, i, &chr);
 
        log_file_advance_fake_cursor(chr, &lineLength, &lineCount);
    }
 
    uint64_t totalLines = lineCount;
    uint64_t linesThatFit = log_screen_get_height();
 
    lineLength = 0;
    lineCount = 0;
 
    uint64_t i = 0;
    for (; i < ring_data_length(&ring) && lineCount < totalLines - linesThatFit; i++)
    {
        uint8_t chr;
        ring_get_byte(&ring, i, &chr);
 
        log_file_advance_fake_cursor(chr, &lineLength, &lineCount);
    }
 
    for (; i < ring_data_length(&ring);)
    {
        uint64_t toRead = MIN(ring_data_length(&ring) - i, sizeof(workingBuffer));
        ring_read_at(&ring, i, workingBuffer, toRead);
        i += toRead;
 
        log_screen_write(workingBuffer, toRead);
    }
}
 
void log_file_write(const char* string, uint64_t length)
{
    if (string == NULL || length == 0)
    {
        return;
    }
 
    LOCK_SCOPE(&lock);
    ring_write(&ring, string, length);
}