/* * Commands to do_syslog: * * 0 -- Close the log. Currently a NOP. * 1 -- Open the log. Currently a NOP. * 2 -- Read from the log. * 3 -- Read all messages remaining in the ring buffer. * 4 -- Read and clear all messages remaining in the ring buffer * 5 -- Clear ring buffer. * 6 -- Disable printk's to console * 7 -- Enable printk's to console * 8 -- Set level of messages printed to console * 9 -- Return number of unread characters in the log buffer * 10 -- Return size of the log buffer */ int do_syslog(int type, char __user * buf, int len) { unsigned long i, j, limit, count; int do_clear = 0; char c; int error = 0; error = security_syslog(type); if (error) return error; switch (type) { case 0: /* Close log */ break; case 1: /* Open log */ break; case 2: /* Read from log */ error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } error = wait_event_interruptible(log_wait, (log_start - log_end)); if (error) goto out; i = 0; spin_lock_irq(&logbuf_lock); while (!error && (log_start != log_end) && i < len) { c = LOG_BUF(log_start); log_start++; spin_unlock_irq(&logbuf_lock); error = __put_user(c,buf); buf++; i++; cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); if (!error) error = i; break; case 4: /* Read/clear last kernel messages */ do_clear = 1; /* FALL THRU */ case 3: /* Read last kernel messages */ error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } count = len; if (count > log_buf_len) count = log_buf_len; spin_lock_irq(&logbuf_lock); if (count > logged_chars) count = logged_chars; if (do_clear) logged_chars = 0; limit = log_end; /* * __put_user() could sleep, and while we sleep * printk() could overwrite the messages * we try to copy to user space. Therefore * the messages are copied in reverse. <manfreds> */ for(i = 0; i < count && !error; i++) { j = limit-1-i; if (j + log_buf_len < log_end) break; c = LOG_BUF(j); spin_unlock_irq(&logbuf_lock); error = __put_user(c,&buf[count-1-i]); cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); if (error) break; error = i; if(i != count) { int offset = count-error; /* buffer overflow during copy, correct user buffer. */ for(i=0;i<error;i++) { if (__get_user(c,&buf[i+offset]) || __put_user(c,&buf[i])) { error = -EFAULT; break; } cond_resched(); } } break; case 5: /* Clear ring buffer */ logged_chars = 0; break; case 6: /* Disable logging to console */ console_loglevel = minimum_console_loglevel; break; case 7: /* Enable logging to console */ console_loglevel = default_console_loglevel; break; case 8: /* Set level of messages printed to console */ error = -EINVAL; if (len < 1 || len > 8) goto out; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; error = 0; break; case 9: /* Number of chars in the log buffer */ error = log_end - log_start; break; case 10: /* Size of the log buffer */ error = log_buf_len; break; default: error = -EINVAL; break; } out: return error; }
int do_syslog(int type, char __user *buf, int len, bool from_file) { unsigned i, j, limit, count; int do_clear = 0; char c; int error; error = check_syslog_permissions(type, from_file); if (error) goto out; error = security_syslog(type); if (error) return error; switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ break; case SYSLOG_ACTION_OPEN: /* Open log */ break; case SYSLOG_ACTION_READ: /* Read from log */ error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } error = wait_event_interruptible(log_wait, (log_start - log_end)); if (error) goto out; i = 0; spin_lock_irq(&logbuf_lock); while (!error && (log_start != log_end) && i < len) { c = LOG_BUF(log_start); log_start++; spin_unlock_irq(&logbuf_lock); error = __put_user(c,buf); buf++; i++; cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); if (!error) error = i; break; /* Read/clear last kernel messages */ case SYSLOG_ACTION_READ_CLEAR: do_clear = 1; /* FALL THRU */ /* Read last kernel messages */ case SYSLOG_ACTION_READ_ALL: error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } count = len; if (count > log_buf_len) count = log_buf_len; spin_lock_irq(&logbuf_lock); if (count > logged_chars) count = logged_chars; if (do_clear) logged_chars = 0; limit = log_end; /* * __put_user() could sleep, and while we sleep * printk() could overwrite the messages * we try to copy to user space. Therefore * the messages are copied in reverse. <manfreds> */ for (i = 0; i < count && !error; i++) { j = limit-1-i; if (j + log_buf_len < log_end) break; c = LOG_BUF(j); spin_unlock_irq(&logbuf_lock); error = __put_user(c,&buf[count-1-i]); cond_resched(); spin_lock_irq(&logbuf_lock); } spin_unlock_irq(&logbuf_lock); if (error) break; error = i; if (i != count) { int offset = count-error; /* buffer overflow during copy, correct user buffer. */ for (i = 0; i < error; i++) { if (__get_user(c,&buf[i+offset]) || __put_user(c,&buf[i])) { error = -EFAULT; break; } cond_resched(); } } break; /* Clear ring buffer */ case SYSLOG_ACTION_CLEAR: logged_chars = 0; break; /* Disable logging to console */ case SYSLOG_ACTION_CONSOLE_OFF: if (saved_console_loglevel == -1) saved_console_loglevel = console_loglevel; console_loglevel = minimum_console_loglevel; break; /* Enable logging to console */ case SYSLOG_ACTION_CONSOLE_ON: if (saved_console_loglevel != -1) { console_loglevel = saved_console_loglevel; saved_console_loglevel = -1; } break; /* Set level of messages printed to console */ case SYSLOG_ACTION_CONSOLE_LEVEL: error = -EINVAL; if (len < 1 || len > 8) goto out; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; /* Implicitly re-enable logging to console */ saved_console_loglevel = -1; error = 0; break; /* Number of chars in the log buffer */ case SYSLOG_ACTION_SIZE_UNREAD: error = log_end - log_start; break; /* Size of the log buffer */ case SYSLOG_ACTION_SIZE_BUFFER: error = log_buf_len; break; default: error = -EINVAL; break; } out: return error; }
int do_syslog(int type, char __user *buf, int len, bool from_file) { unsigned i, j, limit, count; int do_clear = 0; char c; int error; error = check_syslog_permissions(type, from_file); if (error) goto out; error = security_syslog(type); if (error) return error; switch (type) { case SYSLOG_ACTION_CLOSE: break; case SYSLOG_ACTION_OPEN: break; case SYSLOG_ACTION_READ: error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } error = wait_event_interruptible(log_wait, (log_start - log_end)); if (error) goto out; i = 0; raw_spin_lock_irq(&logbuf_lock); while (!error && (log_start != log_end) && i < len) { c = LOG_BUF(log_start); log_start++; raw_spin_unlock_irq(&logbuf_lock); error = __put_user(c,buf); buf++; i++; cond_resched(); raw_spin_lock_irq(&logbuf_lock); } raw_spin_unlock_irq(&logbuf_lock); if (!error) error = i; break; case SYSLOG_ACTION_READ_CLEAR: do_clear = 1; case SYSLOG_ACTION_READ_ALL: error = -EINVAL; if (!buf || len < 0) goto out; error = 0; if (!len) goto out; if (!access_ok(VERIFY_WRITE, buf, len)) { error = -EFAULT; goto out; } count = len; if (count > log_buf_len) count = log_buf_len; raw_spin_lock_irq(&logbuf_lock); if (count > logged_chars) count = logged_chars; if (do_clear) logged_chars = 0; limit = log_end; for (i = 0; i < count && !error; i++) { j = limit-1-i; if (j + log_buf_len < log_end) break; c = LOG_BUF(j); raw_spin_unlock_irq(&logbuf_lock); error = __put_user(c,&buf[count-1-i]); cond_resched(); raw_spin_lock_irq(&logbuf_lock); } raw_spin_unlock_irq(&logbuf_lock); if (error) break; error = i; if (i != count) { int offset = count-error; for (i = 0; i < error; i++) { if (__get_user(c,&buf[i+offset]) || __put_user(c,&buf[i])) { error = -EFAULT; break; } cond_resched(); } } break; case SYSLOG_ACTION_CLEAR: logged_chars = 0; break; case SYSLOG_ACTION_CONSOLE_OFF: if (saved_console_loglevel == -1) saved_console_loglevel = console_loglevel; console_loglevel = minimum_console_loglevel; break; case SYSLOG_ACTION_CONSOLE_ON: if (saved_console_loglevel != -1) { console_loglevel = saved_console_loglevel; saved_console_loglevel = -1; } break; case SYSLOG_ACTION_CONSOLE_LEVEL: error = -EINVAL; if (len < 1 || len > 8) goto out; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; saved_console_loglevel = -1; error = 0; break; case SYSLOG_ACTION_SIZE_UNREAD: error = log_end - log_start; break; case SYSLOG_ACTION_SIZE_BUFFER: error = log_buf_len; break; default: error = -EINVAL; break; } out: return error; }