/**************************************************************************** * drivers/syslog/syslog_intbuffer.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include "syslog.h" #ifdef CONFIG_SYSLOG_INTBUFFER /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #if CONFIG_SYSLOG_INTBUFSIZE > 65535 # undef CONFIG_SYSLOG_INTBUFSIZE # define CONFIG_SYSLOG_INTBUFSIZE 65535 #endif /**************************************************************************** * Private Types ****************************************************************************/ /* This structure encapsulates the interrupt buffer state */ struct g_syslog_intbuffer_s { volatile uint16_t si_inndx; volatile uint16_t si_outndx; uint8_t si_buffer[CONFIG_SYSLOG_INTBUFSIZE]; }; /**************************************************************************** * Private Data ****************************************************************************/ static struct g_syslog_intbuffer_s g_syslog_intbuffer; /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Name: syslog_remove_intbuffer * * Description: * Extract any characters that may have been added to the interrupt buffer * to the SYSLOG device. * * Input Parameters: * None * * Returned Value: * On success, the extracted character is returned. EOF is returned if * the interrupt buffer is empty. * * Assumptions: * Interrupts may or may not be disabled. * ****************************************************************************/ int syslog_remove_intbuffer(void) { irqstate_t flags; uint32_t outndx; int ret = EOF; /* Extraction of the character and adjustment of the circular buffer * indices must be performed in a critical section to protect from * concurrent modification from interrupt handlers. */ flags = enter_critical_section(); /* Check if the interrupt buffer is empty */ outndx = (uint32_t)g_syslog_intbuffer.si_outndx; if (outndx != (uint32_t)g_syslog_intbuffer.si_inndx) { /* Not empty.. Take the next character from the interrupt buffer */ ret = g_syslog_intbuffer.si_buffer[outndx]; /* Increment the OUT index, handling wrap-around */ if (++outndx >= CONFIG_SYSLOG_INTBUFSIZE) { outndx -= CONFIG_SYSLOG_INTBUFSIZE; } g_syslog_intbuffer.si_outndx = (uint16_t)outndx; } leave_critical_section(flags); /* Now we can send the extracted character to the SYSLOG device */ return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: syslog_add_intbuffer * * Description: * Add one more character to the interrupt buffer. In the event of * buffer overflowed, the character will be dropped. The indication * "[truncated]\n" will be appended to the end of the interrupt buffer. * * Input Parameters: * ch - The character to add to the interrupt buffer (must be positive). * * Returned Value: * Zero success, the character is echoed back to the caller. A negated * errno value is returned on any failure. * * Assumptions: * - Called either from (1) interrupt handling logic with interrupts * disabled or from an IDLE thread with interrupts enabled. * - Requires caution because there may be an interrupted execution of * syslog_flush_intbuffer(): Only the outndx can be modified. * ****************************************************************************/ int syslog_add_intbuffer(int ch) { irqstate_t flags; uint32_t inndx; uint32_t outndx; uint32_t endndx; unsigned int inuse; int ret = OK; int i; /* Disable concurrent modification from interrupt handling logic */ flags = enter_critical_section(); /* How much space is left in the intbuffer? */ inndx = (uint32_t)g_syslog_intbuffer.si_inndx; outndx = (uint32_t)g_syslog_intbuffer.si_outndx; endndx = inndx; if (endndx < outndx) { endndx += CONFIG_SYSLOG_INTBUFSIZE; } inuse = (unsigned int)(endndx - outndx); /* Is there space for another character */ if (inuse == CONFIG_SYSLOG_INTBUFSIZE - 1) { int oldch = syslog_remove_intbuffer(); for (i = 0; i < CONFIG_SYSLOG_MAX_CHANNELS; i++) { if (g_syslog_channel[i] == NULL) { break; } #ifdef CONFIG_SYSLOG_IOCTL if (g_syslog_channel[i]->sc_disable) { continue; } #endif /* Select which putc function to use for this flush */ if (g_syslog_channel[i]->sc_ops->sc_force) { g_syslog_channel[i]->sc_ops->sc_force( g_syslog_channel[i], oldch); } } ret = -ENOSPC; } /* Copy one character */ g_syslog_intbuffer.si_buffer[inndx] = (uint8_t)ch; /* Increment the IN index, handling wrap-around */ if (++inndx >= CONFIG_SYSLOG_INTBUFSIZE) { inndx -= CONFIG_SYSLOG_INTBUFSIZE; } g_syslog_intbuffer.si_inndx = (uint16_t)inndx; leave_critical_section(flags); return ret; } /**************************************************************************** * Name: syslog_flush_intbuffer * * Description: * Flush any characters that may have been added to the interrupt buffer * to the SYSLOG device. * * Input Parameters: * force - Use the force() method of the channel vs. the putc() method. * * Returned Value: * On success, the character is echoed back to the caller. A negated * errno value is returned on any failure. * * Assumptions: * Interrupts may or may not be disabled. * ****************************************************************************/ int syslog_flush_intbuffer(bool force) { syslog_putc_t putfunc; irqstate_t flags; int ch; int i; /* This logic is performed with the scheduler disabled to protect from * concurrent modification by other tasks. */ flags = enter_critical_section(); do { /* Transfer one character to time. This is inefficient, but is * done in this way to: (1) Deal with concurrent modification of * the interrupt buffer from interrupt activity, (2) Avoid keeper * interrupts disabled for a long time, and (3) to handler * wrap-around of the circular buffer indices. */ ch = syslog_remove_intbuffer(); for (i = 0; i < CONFIG_SYSLOG_MAX_CHANNELS; i++) { if ((g_syslog_channel[i] == NULL) || (ch == EOF)) { break; } #ifdef CONFIG_SYSLOG_IOCTL if (g_syslog_channel[i]->sc_disable) { continue; } #endif /* Select which putc function to use for this flush */ putfunc = force ? g_syslog_channel[i]->sc_ops->sc_force : g_syslog_channel[i]->sc_ops->sc_putc; putfunc(g_syslog_channel[i], ch); } } while (ch != EOF); leave_critical_section(flags); return ch; } #endif /* CONFIG_SYSLOG_INTBUFFER */