diff options
Diffstat (limited to 'libc/bionic/logd_write.c')
| -rw-r--r-- | libc/bionic/logd_write.c | 47 |
1 files changed, 32 insertions, 15 deletions
diff --git a/libc/bionic/logd_write.c b/libc/bionic/logd_write.c index 63dfd596b..2bc39fa4f 100644 --- a/libc/bionic/logd_write.c +++ b/libc/bionic/logd_write.c @@ -48,6 +48,16 @@ #include <pthread.h> +/* IMPORTANT IMPORTANT IMPORTANT: TECHNICAL NOTE + * + * Some of the functions below can be called when our malloc() implementation + * has detected that the heap is corrupted, or even from a signal handler. + * + * These functions should *not* use a function that allocates heap memory + * or is not signal-safe. Using direct system calls is acceptable, and we + * also assume that pthread_mutex_lock/unlock can be used too. + */ + #define LOG_BUF_SIZE 1024 typedef enum { @@ -77,9 +87,10 @@ static log_channel_t log_channels[LOG_ID_MAX] = { { __write_to_log_init, -1, "/dev/"LOGGER_LOG_RADIO } }; +/* Important: see technical note at start of source file */ static int __write_to_log_null(log_id_t log_id, struct iovec *vec) { - /* + /* * ALTERED behaviour from previous version * always returns successful result */ @@ -97,23 +108,21 @@ static int __write_to_log_null(log_id_t log_id, struct iovec *vec) * it's supposed, that log_id contains valid id always. * this check must be performed in higher level functions */ +/* Important: see technical note at start of source file */ static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec) { - ssize_t ret; - - do { - ret = writev(log_channels[log_id].fd, vec, 3); - } while ((ret < 0) && (errno == EINTR)); - - return ret; + return TEMP_FAILURE_RETRY( writev(log_channels[log_id].fd, vec, 3) ); } +/* Important: see technical note at start of source file */ static int __write_to_log_init(log_id_t log_id, struct iovec *vec) { if ((LOG_ID_NONE < log_id) && (log_id < LOG_ID_MAX)) { + int fd; + pthread_mutex_lock(&log_init_lock); - int fd = open(log_channels[log_id].path, O_WRONLY); + fd = TEMP_FAILURE_RETRY(open(log_channels[log_id].path, O_WRONLY)); log_channels[log_id].logger = (fd < 0) ? __write_to_log_null : __write_to_log_kernel; @@ -130,7 +139,9 @@ static int __write_to_log_init(log_id_t log_id, struct iovec *vec) return -1; } -static int __android_log_write(int prio, const char *tag, const char *msg) +/* Important: see technical note at start of source file */ +__LIBC_HIDDEN__ +int __libc_android_log_write(int prio, const char *tag, const char *msg) { struct iovec vec[3]; log_id_t log_id = LOG_ID_MAIN; @@ -151,7 +162,11 @@ static int __android_log_write(int prio, const char *tag, const char *msg) return log_channels[log_id].logger(log_id, vec); } - +/* The functions below are not designed to be called from a heap panic + * function or from a signal handler. As such, they are free to use complex + * C library functions like vsnprintf() + */ +__LIBC_HIDDEN__ int __libc_android_log_vprint(int prio, const char *tag, const char *fmt, va_list ap) { @@ -159,9 +174,10 @@ int __libc_android_log_vprint(int prio, const char *tag, const char *fmt, vsnprintf(buf, LOG_BUF_SIZE, fmt, ap); - return __android_log_write(prio, tag, buf); + return __libc_android_log_write(prio, tag, buf); } +__LIBC_HIDDEN__ int __libc_android_log_print(int prio, const char *tag, const char *fmt, ...) { va_list ap; @@ -171,20 +187,21 @@ int __libc_android_log_print(int prio, const char *tag, const char *fmt, ...) vsnprintf(buf, LOG_BUF_SIZE, fmt, ap); va_end(ap); - return __android_log_write(prio, tag, buf); + return __libc_android_log_write(prio, tag, buf); } +__LIBC_HIDDEN__ int __libc_android_log_assert(const char *cond, const char *tag, const char *fmt, ...) { va_list ap; - char buf[LOG_BUF_SIZE]; + char buf[LOG_BUF_SIZE]; va_start(ap, fmt); vsnprintf(buf, LOG_BUF_SIZE, fmt, ap); va_end(ap); - __android_log_write(ANDROID_LOG_FATAL, tag, buf); + __libc_android_log_write(ANDROID_LOG_FATAL, tag, buf); exit(1); |