diff options
Diffstat (limited to 'drivers/staging/android/logger.c')
| -rw-r--r-- | drivers/staging/android/logger.c | 442 |
1 files changed, 340 insertions, 102 deletions
diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index ffc2d043dd8..2772e01b37f 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -17,6 +17,8 @@ * GNU General Public License for more details. */ +#define pr_fmt(fmt) "logger: " fmt + #include <linux/sched.h> #include <linux/module.h> #include <linux/fs.h> @@ -25,42 +27,68 @@ #include <linux/poll.h> #include <linux/slab.h> #include <linux/time.h> +#include <linux/vmalloc.h> +#include <linux/aio.h> #include "logger.h" #include <asm/ioctls.h> -/* +/** * struct logger_log - represents a specific log, such as 'main' or 'radio' + * @buffer: The actual ring buffer + * @misc: The "misc" device representing the log + * @wq: The wait queue for @readers + * @readers: This log's readers + * @mutex: The mutex that protects the @buffer + * @w_off: The current write head offset + * @head: The head, or location that readers start reading at. + * @size: The size of the log + * @logs: The list of log channels * * This structure lives from module insertion until module removal, so it does * not need additional reference counting. The structure is protected by the * mutex 'mutex'. */ struct logger_log { - unsigned char *buffer;/* the ring buffer itself */ - struct miscdevice misc; /* misc device representing the log */ - wait_queue_head_t wq; /* wait queue for readers */ - struct list_head readers; /* this log's readers */ - struct mutex mutex; /* mutex protecting buffer */ - size_t w_off; /* current write head offset */ - size_t head; /* new readers start here */ - size_t size; /* size of the log */ + unsigned char *buffer; + struct miscdevice misc; + wait_queue_head_t wq; + struct list_head readers; + struct mutex mutex; + size_t w_off; + size_t head; + size_t size; + struct list_head logs; }; -/* +static LIST_HEAD(log_list); + + +/** * struct logger_reader - a logging device open for reading + * @log: The associated log + * @list: The associated entry in @logger_log's list + * @r_off: The current read head offset. + * @r_all: Reader can read all entries + * @r_ver: Reader ABI version * * This object lives from open to release, so we don't need additional * reference counting. The structure is protected by log->mutex. */ struct logger_reader { - struct logger_log *log; /* associated log */ - struct list_head list; /* entry in logger_log's list */ - size_t r_off; /* current read head offset */ + struct logger_log *log; + struct list_head list; + size_t r_off; + bool r_all; + int r_ver; }; /* logger_offset - returns index 'n' into the log via (optimized) modulus */ -#define logger_offset(n) ((n) & (log->size - 1)) +static size_t logger_offset(struct logger_log *log, size_t n) +{ + return n & (log->size - 1); +} + /* * file_get_log - Given a file structure, return the associated log @@ -80,31 +108,83 @@ static inline struct logger_log *file_get_log(struct file *file) { if (file->f_mode & FMODE_READ) { struct logger_reader *reader = file->private_data; + return reader->log; } else return file->private_data; } /* - * get_entry_len - Grabs the length of the payload of the next entry starting - * from 'off'. + * get_entry_header - returns a pointer to the logger_entry header within + * 'log' starting at offset 'off'. A temporary logger_entry 'scratch' must + * be provided. Typically the return value will be a pointer within + * 'logger->buf'. However, a pointer to 'scratch' may be returned if + * the log entry spans the end and beginning of the circular buffer. + */ +static struct logger_entry *get_entry_header(struct logger_log *log, + size_t off, struct logger_entry *scratch) +{ + size_t len = min(sizeof(struct logger_entry), log->size - off); + + if (len != sizeof(struct logger_entry)) { + memcpy(((void *) scratch), log->buffer + off, len); + memcpy(((void *) scratch) + len, log->buffer, + sizeof(struct logger_entry) - len); + return scratch; + } + + return (struct logger_entry *) (log->buffer + off); +} + +/* + * get_entry_msg_len - Grabs the length of the message of the entry + * starting from from 'off'. + * + * An entry length is 2 bytes (16 bits) in host endian order. + * In the log, the length does not include the size of the log entry structure. + * This function returns the size including the log entry structure. * * Caller needs to hold log->mutex. */ -static __u32 get_entry_len(struct logger_log *log, size_t off) +static __u32 get_entry_msg_len(struct logger_log *log, size_t off) { - __u16 val; + struct logger_entry scratch; + struct logger_entry *entry; - switch (log->size - off) { - case 1: - memcpy(&val, log->buffer + off, 1); - memcpy(((char *) &val) + 1, log->buffer, 1); - break; - default: - memcpy(&val, log->buffer + off, 2); + entry = get_entry_header(log, off, &scratch); + return entry->len; +} + +static size_t get_user_hdr_len(int ver) +{ + if (ver < 2) + return sizeof(struct user_logger_entry_compat); + else + return sizeof(struct logger_entry); +} + +static ssize_t copy_header_to_user(int ver, struct logger_entry *entry, + char __user *buf) +{ + void *hdr; + size_t hdr_len; + struct user_logger_entry_compat v1; + + if (ver < 2) { + v1.len = entry->len; + v1.__pad = 0; + v1.pid = entry->pid; + v1.tid = entry->tid; + v1.sec = entry->sec; + v1.nsec = entry->nsec; + hdr = &v1; + hdr_len = sizeof(struct user_logger_entry_compat); + } else { + hdr = entry; + hdr_len = sizeof(struct logger_entry); } - return sizeof(struct logger_entry) + val; + return copy_to_user(buf, hdr, hdr_len); } /* @@ -118,15 +198,31 @@ static ssize_t do_read_log_to_user(struct logger_log *log, char __user *buf, size_t count) { + struct logger_entry scratch; + struct logger_entry *entry; size_t len; + size_t msg_start; + + /* + * First, copy the header to userspace, using the version of + * the header requested + */ + entry = get_entry_header(log, reader->r_off, &scratch); + if (copy_header_to_user(reader->r_ver, entry, buf)) + return -EFAULT; + + count -= get_user_hdr_len(reader->r_ver); + buf += get_user_hdr_len(reader->r_ver); + msg_start = logger_offset(log, + reader->r_off + sizeof(struct logger_entry)); /* - * We read from the log in two disjoint operations. First, we read from - * the current read head offset up to 'count' bytes or to the end of + * We read from the msg in two disjoint operations. First, we read from + * the current msg head offset up to 'count' bytes or to the end of * the log, whichever comes first. */ - len = min(count, log->size - reader->r_off); - if (copy_to_user(buf, log->buffer + reader->r_off, len)) + len = min(count, log->size - msg_start); + if (copy_to_user(buf, log->buffer + msg_start, len)) return -EFAULT; /* @@ -137,9 +233,34 @@ static ssize_t do_read_log_to_user(struct logger_log *log, if (copy_to_user(buf + len, log->buffer, count - len)) return -EFAULT; - reader->r_off = logger_offset(reader->r_off + count); + reader->r_off = logger_offset(log, reader->r_off + + sizeof(struct logger_entry) + count); - return count; + return count + get_user_hdr_len(reader->r_ver); +} + +/* + * get_next_entry_by_uid - Starting at 'off', returns an offset into + * 'log->buffer' which contains the first entry readable by 'euid' + */ +static size_t get_next_entry_by_uid(struct logger_log *log, + size_t off, kuid_t euid) +{ + while (off != log->w_off) { + struct logger_entry *entry; + struct logger_entry scratch; + size_t next_len; + + entry = get_entry_header(log, off, &scratch); + + if (uid_eq(entry->euid, euid)) + return off; + + next_len = sizeof(struct logger_entry) + entry->len; + off = logger_offset(log, off + next_len); + } + + return off; } /* @@ -151,7 +272,7 @@ static ssize_t do_read_log_to_user(struct logger_log *log, * - If there are no log entries to read, blocks until log is written to * - Atomically reads exactly one log entry * - * Optimal read size is LOGGER_ENTRY_MAX_LEN. Will set errno to EINVAL if read + * Will set errno to EINVAL if read * buffer is insufficient to hold next entry. */ static ssize_t logger_read(struct file *file, char __user *buf, @@ -164,9 +285,10 @@ static ssize_t logger_read(struct file *file, char __user *buf, start: while (1) { + mutex_lock(&log->mutex); + prepare_to_wait(&log->wq, &wait, TASK_INTERRUPTIBLE); - mutex_lock(&log->mutex); ret = (log->w_off == reader->r_off); mutex_unlock(&log->mutex); if (!ret) @@ -191,6 +313,10 @@ start: mutex_lock(&log->mutex); + if (!reader->r_all) + reader->r_off = get_next_entry_by_uid(log, + reader->r_off, current_euid()); + /* is there still something to read or did we race? */ if (unlikely(log->w_off == reader->r_off)) { mutex_unlock(&log->mutex); @@ -198,7 +324,8 @@ start: } /* get the size of the next entry */ - ret = get_entry_len(log, reader->r_off); + ret = get_user_hdr_len(reader->r_ver) + + get_entry_msg_len(log, reader->r_off); if (count < ret) { ret = -EINVAL; goto out; @@ -224,8 +351,9 @@ static size_t get_next_entry(struct logger_log *log, size_t off, size_t len) size_t count = 0; do { - size_t nr = get_entry_len(log, off); - off = logger_offset(off + nr); + size_t nr = sizeof(struct logger_entry) + + get_entry_msg_len(log, off); + off = logger_offset(log, off + nr); count += nr; } while (count < len); @@ -233,16 +361,28 @@ static size_t get_next_entry(struct logger_log *log, size_t off, size_t len) } /* - * clock_interval - is a < c < b in mod-space? Put another way, does the line - * from a to b cross c? + * is_between - is a < c < b, accounting for wrapping of a, b, and c + * positions in the buffer + * + * That is, if a<b, check for c between a and b + * and if a>b, check for c outside (not between) a and b + * + * |------- a xxxxxxxx b --------| + * c^ + * + * |xxxxx b --------- a xxxxxxxxx| + * c^ + * or c^ */ -static inline int clock_interval(size_t a, size_t b, size_t c) +static inline int is_between(size_t a, size_t b, size_t c) { - if (b < a) { - if (a < c || b >= c) + if (a < b) { + /* is c between a and b? */ + if (a < c && c <= b) return 1; } else { - if (a < c && b >= c) + /* is c outside of b through a? */ + if (c <= b || a < c) return 1; } @@ -260,14 +400,14 @@ static inline int clock_interval(size_t a, size_t b, size_t c) static void fix_up_readers(struct logger_log *log, size_t len) { size_t old = log->w_off; - size_t new = logger_offset(old + len); + size_t new = logger_offset(log, old + len); struct logger_reader *reader; - if (clock_interval(old, new, log->head)) + if (is_between(old, new, log->head)) log->head = get_next_entry(log, log->head, len); list_for_each_entry(reader, &log->readers, list) - if (clock_interval(old, new, reader->r_off)) + if (is_between(old, new, reader->r_off)) reader->r_off = get_next_entry(log, reader->r_off, len); } @@ -286,7 +426,7 @@ static void do_write_log(struct logger_log *log, const void *buf, size_t count) if (count != len) memcpy(log->buffer, buf + len, count - len); - log->w_off = logger_offset(log->w_off + count); + log->w_off = logger_offset(log, log->w_off + count); } @@ -309,9 +449,15 @@ static ssize_t do_write_log_from_user(struct logger_log *log, if (count != len) if (copy_from_user(log->buffer, buf + len, count - len)) + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ return -EFAULT; - log->w_off = logger_offset(log->w_off + count); + log->w_off = logger_offset(log, log->w_off + count); return count; } @@ -321,11 +467,11 @@ static ssize_t do_write_log_from_user(struct logger_log *log, * writev(), and aio_write(). Writes are our fast path, and we try to optimize * them above all else. */ -ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, +static ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t ppos) { struct logger_log *log = file_get_log(iocb->ki_filp); - size_t orig = log->w_off; + size_t orig; struct logger_entry header; struct timespec now; ssize_t ret = 0; @@ -336,7 +482,9 @@ ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, header.tid = current->pid; header.sec = now.tv_sec; header.nsec = now.tv_nsec; - header.len = min_t(size_t, iocb->ki_left, LOGGER_ENTRY_MAX_PAYLOAD); + header.euid = current_euid(); + header.len = min_t(size_t, iocb->ki_nbytes, LOGGER_ENTRY_MAX_PAYLOAD); + header.hdr_size = sizeof(struct logger_entry); /* null writes succeed, return zero */ if (unlikely(!header.len)) @@ -344,6 +492,8 @@ ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, mutex_lock(&log->mutex); + orig = log->w_off; + /* * Fix up any readers, pulling them forward to the first readable * entry after (what will be) the new write offset. We do this now @@ -381,7 +531,15 @@ ssize_t logger_aio_write(struct kiocb *iocb, const struct iovec *iov, return ret; } -static struct logger_log *get_log_from_minor(int); +static struct logger_log *get_log_from_minor(int minor) +{ + struct logger_log *log; + + list_for_each_entry(log, &log_list, logs) + if (log->misc.minor == minor) + return log; + return NULL; +} /* * logger_open - the log's open() file operation @@ -409,6 +567,10 @@ static int logger_open(struct inode *inode, struct file *file) return -ENOMEM; reader->log = log; + reader->r_ver = 1; + reader->r_all = in_egroup_p(inode->i_gid) || + capable(CAP_SYSLOG); + INIT_LIST_HEAD(&reader->list); mutex_lock(&log->mutex); @@ -432,7 +594,12 @@ static int logger_release(struct inode *ignored, struct file *file) { if (file->f_mode & FMODE_READ) { struct logger_reader *reader = file->private_data; + struct logger_log *log = reader->log; + + mutex_lock(&log->mutex); list_del(&reader->list); + mutex_unlock(&log->mutex); + kfree(reader); } @@ -463,6 +630,10 @@ static unsigned int logger_poll(struct file *file, poll_table *wait) poll_wait(file, &log->wq, wait); mutex_lock(&log->mutex); + if (!reader->r_all) + reader->r_off = get_next_entry_by_uid(log, + reader->r_off, current_euid()); + if (log->w_off != reader->r_off) ret |= POLLIN | POLLRDNORM; mutex_unlock(&log->mutex); @@ -470,11 +641,26 @@ static unsigned int logger_poll(struct file *file, poll_table *wait) return ret; } +static long logger_set_version(struct logger_reader *reader, void __user *arg) +{ + int version; + + if (copy_from_user(&version, arg, sizeof(int))) + return -EFAULT; + + if ((version < 1) || (version > 2)) + return -EINVAL; + + reader->r_ver = version; + return 0; +} + static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct logger_log *log = file_get_log(file); struct logger_reader *reader; - long ret = -ENOTTY; + long ret = -EINVAL; + void __user *argp = (void __user *) arg; mutex_lock(&log->mutex); @@ -499,8 +685,14 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg) break; } reader = file->private_data; + + if (!reader->r_all) + reader->r_off = get_next_entry_by_uid(log, + reader->r_off, current_euid()); + if (log->w_off != reader->r_off) - ret = get_entry_len(log, reader->r_off); + ret = get_user_hdr_len(reader->r_ver) + + get_entry_msg_len(log, reader->r_off); else ret = 0; break; @@ -509,11 +701,32 @@ static long logger_ioctl(struct file *file, unsigned int cmd, unsigned long arg) ret = -EBADF; break; } + if (!(in_egroup_p(file_inode(file)->i_gid) || + capable(CAP_SYSLOG))) { + ret = -EPERM; + break; + } list_for_each_entry(reader, &log->readers, list) reader->r_off = log->w_off; log->head = log->w_off; ret = 0; break; + case LOGGER_GET_VERSION: + if (!(file->f_mode & FMODE_READ)) { + ret = -EBADF; + break; + } + reader = file->private_data; + ret = reader->r_ver; + break; + case LOGGER_SET_VERSION: + if (!(file->f_mode & FMODE_READ)) { + ret = -EBADF; + break; + } + reader = file->private_data; + ret = logger_set_version(reader, argp); + break; } mutex_unlock(&log->mutex); @@ -533,84 +746,109 @@ static const struct file_operations logger_fops = { }; /* - * Defines a log structure with name 'NAME' and a size of 'SIZE' bytes, which - * must be a power of two, greater than LOGGER_ENTRY_MAX_LEN, and less than - * LONG_MAX minus LOGGER_ENTRY_MAX_LEN. + * Log size must must be a power of two, and greater than + * (LOGGER_ENTRY_MAX_PAYLOAD + sizeof(struct logger_entry)). */ -#define DEFINE_LOGGER_DEVICE(VAR, NAME, SIZE) \ -static unsigned char _buf_ ## VAR[SIZE]; \ -static struct logger_log VAR = { \ - .buffer = _buf_ ## VAR, \ - .misc = { \ - .minor = MISC_DYNAMIC_MINOR, \ - .name = NAME, \ - .fops = &logger_fops, \ - .parent = NULL, \ - }, \ - .wq = __WAIT_QUEUE_HEAD_INITIALIZER(VAR .wq), \ - .readers = LIST_HEAD_INIT(VAR .readers), \ - .mutex = __MUTEX_INITIALIZER(VAR .mutex), \ - .w_off = 0, \ - .head = 0, \ - .size = SIZE, \ -}; +static int __init create_log(char *log_name, int size) +{ + int ret = 0; + struct logger_log *log; + unsigned char *buffer; -DEFINE_LOGGER_DEVICE(log_main, LOGGER_LOG_MAIN, 256*1024) -DEFINE_LOGGER_DEVICE(log_events, LOGGER_LOG_EVENTS, 256*1024) -DEFINE_LOGGER_DEVICE(log_radio, LOGGER_LOG_RADIO, 256*1024) -DEFINE_LOGGER_DEVICE(log_system, LOGGER_LOG_SYSTEM, 256*1024) + buffer = vmalloc(size); + if (buffer == NULL) + return -ENOMEM; -static struct logger_log *get_log_from_minor(int minor) -{ - if (log_main.misc.minor == minor) - return &log_main; - if (log_events.misc.minor == minor) - return &log_events; - if (log_radio.misc.minor == minor) - return &log_radio; - if (log_system.misc.minor == minor) - return &log_system; - return NULL; -} + log = kzalloc(sizeof(struct logger_log), GFP_KERNEL); + if (log == NULL) { + ret = -ENOMEM; + goto out_free_buffer; + } + log->buffer = buffer; -static int __init init_log(struct logger_log *log) -{ - int ret; + log->misc.minor = MISC_DYNAMIC_MINOR; + log->misc.name = kstrdup(log_name, GFP_KERNEL); + if (log->misc.name == NULL) { + ret = -ENOMEM; + goto out_free_log; + } + log->misc.fops = &logger_fops; + log->misc.parent = NULL; + + init_waitqueue_head(&log->wq); + INIT_LIST_HEAD(&log->readers); + mutex_init(&log->mutex); + log->w_off = 0; + log->head = 0; + log->size = size; + + INIT_LIST_HEAD(&log->logs); + list_add_tail(&log->logs, &log_list); + + /* finally, initialize the misc device for this log */ ret = misc_register(&log->misc); if (unlikely(ret)) { - printk(KERN_ERR "logger: failed to register misc " - "device for log '%s'!\n", log->misc.name); - return ret; + pr_err("failed to register misc device for log '%s'!\n", + log->misc.name); + goto out_free_log; } - printk(KERN_INFO "logger: created %luK log '%s'\n", - (unsigned long) log->size >> 10, log->misc.name); + pr_info("created %luK log '%s'\n", + (unsigned long) log->size >> 10, log->misc.name); return 0; + +out_free_log: + kfree(log); + +out_free_buffer: + vfree(buffer); + return ret; } static int __init logger_init(void) { int ret; - ret = init_log(&log_main); + ret = create_log(LOGGER_LOG_MAIN, 256*1024); if (unlikely(ret)) goto out; - ret = init_log(&log_events); + ret = create_log(LOGGER_LOG_EVENTS, 256*1024); if (unlikely(ret)) goto out; - ret = init_log(&log_radio); + ret = create_log(LOGGER_LOG_RADIO, 256*1024); if (unlikely(ret)) goto out; - ret = init_log(&log_system); + ret = create_log(LOGGER_LOG_SYSTEM, 256*1024); if (unlikely(ret)) goto out; out: return ret; } + +static void __exit logger_exit(void) +{ + struct logger_log *current_log, *next_log; + + list_for_each_entry_safe(current_log, next_log, &log_list, logs) { + /* we have to delete all the entry inside log_list */ + misc_deregister(¤t_log->misc); + vfree(current_log->buffer); + kfree(current_log->misc.name); + list_del(¤t_log->logs); + kfree(current_log); + } +} + + device_initcall(logger_init); +module_exit(logger_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Robert Love, <rlove@google.com>"); +MODULE_DESCRIPTION("Android Logger"); |
