diff options
Diffstat (limited to 'vmcore-dmesg/vmcore-dmesg.c')
| -rw-r--r-- | vmcore-dmesg/vmcore-dmesg.c | 227 |
1 files changed, 221 insertions, 6 deletions
diff --git a/vmcore-dmesg/vmcore-dmesg.c b/vmcore-dmesg/vmcore-dmesg.c index 2e692de0..ff35740c 100644 --- a/vmcore-dmesg/vmcore-dmesg.c +++ b/vmcore-dmesg/vmcore-dmesg.c @@ -15,6 +15,7 @@ #include <fcntl.h> #include <elf.h> #include <stdbool.h> +#include <inttypes.h> /* The 32bit and 64bit note headers make it clear we don't care */ typedef Elf32_Nhdr Elf_Nhdr; @@ -29,6 +30,18 @@ static loff_t log_end_vaddr; static loff_t log_buf_len_vaddr; static loff_t logged_chars_vaddr; +/* record format logs */ +static loff_t log_first_idx_vaddr; +static loff_t log_next_idx_vaddr; + +/* struct log size */ +static uint64_t log_sz; + +/* struct log field offsets */ +static uint64_t log_offset_ts_nsec = UINT64_MAX; +static uint16_t log_offset_len = UINT16_MAX; +static uint16_t log_offset_text_len = UINT16_MAX; + #if __BYTE_ORDER == __LITTLE_ENDIAN #define ELFDATANATIVE ELFDATA2LSB #elif __BYTE_ORDER == __BIG_ENDIAN @@ -240,6 +253,8 @@ static void scan_vmcoreinfo(char *start, size_t size) SYMBOL(log_end), SYMBOL(log_buf_len), SYMBOL(logged_chars), + SYMBOL(log_first_idx), + SYMBOL(log_next_idx), }; for (pos = start; pos <= last; pos = eol + 1) { @@ -291,6 +306,20 @@ static void scan_vmcoreinfo(char *start, size_t size) *symbol[i].vaddr = vaddr; } + /* Check for "SIZE(log)=" */ + if (memcmp("SIZE(log)=", pos, 10) == 0) + log_sz = strtoull(pos + 10, NULL, 10); + + /* Check for struct log field offsets */ + if (memcmp("OFFSET(log.ts_nsec)=", pos, 20) == 0) + log_offset_ts_nsec = strtoull(pos + 20, NULL, 10); + + if (memcmp("OFFSET(log.len)=", pos, 16) == 0) + log_offset_len = strtoul(pos + 16, NULL, 10); + + if (memcmp("OFFSET(log.text_len)=", pos, 21) == 0) + log_offset_text_len = strtoul(pos + 21, NULL, 10); + if (last_line) break; } @@ -400,7 +429,19 @@ static int32_t read_file_s32(int fd, uint64_t addr) return read_file_u32(fd, addr); } -static void dump_dmesg(int fd) +static void write_to_stdout(char *buf, unsigned int nr) +{ + ssize_t ret; + + ret = write(STDOUT_FILENO, buf, nr); + if (ret != nr) { + fprintf(stderr, "Failed to write out the dmesg log buffer!:" + " %s\n", strerror(errno)); + exit(54); + } +} + +static void dump_dmesg_legacy(int fd) { uint64_t log_buf, log_buf_offset; unsigned log_end, logged_chars, log_end_wrapped; @@ -455,12 +496,186 @@ static void dump_dmesg(int fd) strerror(errno)); exit(53); } - ret = write(STDOUT_FILENO, buf + (log_buf_len - logged_chars), logged_chars); - if (ret != logged_chars) { - fprintf(stderr, "Failed to write out the dmesg log buffer!: %s\n", - strerror(errno)); - exit(54); + + write_to_stdout(buf + (log_buf_len - logged_chars), logged_chars); +} + +static inline uint16_t struct_val_u16(char *ptr, unsigned int offset) +{ + return(file16_to_cpu(*(uint16_t *)(ptr + offset))); +} + +static inline uint32_t struct_val_u32(char *ptr, unsigned int offset) +{ + return(file32_to_cpu(*(uint32_t *)(ptr + offset))); +} + +static inline uint32_t struct_val_u64(char *ptr, unsigned int offset) +{ + return(file64_to_cpu(*(uint64_t *)(ptr + offset))); +} + +/* human readable text of the record */ +static char *log_text(char *msg) +{ + return msg + log_sz; +} + +/* get record by index; idx must point to valid msg */ +static char *log_from_idx(char *log_buf, uint32_t idx) +{ + char *msg = log_buf + idx; + + /* + * A length == 0 record is the end of buffer marker. Wrap around and + * read the message at the start of the buffer. + */ + if (!struct_val_u16(msg, log_offset_len)) + return log_buf; + return msg; +} + +/* get next record; idx must point to valid msg */ +static uint32_t log_next(char *log_buf, uint32_t idx) +{ + char *msg = log_buf + idx; + uint16_t len; + + /* length == 0 indicates the end of the buffer; wrap */ + /* + * A length == 0 record is the end of buffer marker. Wrap around and + * read the message at the start of the buffer as *this* one, and + * return the one after that. + */ + len = struct_val_u16(msg, log_offset_len); + if (!len) { + msg = log_buf; + return struct_val_u16(msg, log_offset_len); + } + return idx + len; +} + +/* Read headers of log records and dump accordingly */ +static void dump_dmesg_structured(int fd) +{ +#define OUT_BUF_SIZE 4096 + uint64_t log_buf, log_buf_offset, ts_nsec; + uint32_t log_first_idx, log_next_idx, current_idx, len = 0, i; + int log_buf_len; + char *buf, out_buf[OUT_BUF_SIZE]; + ssize_t ret; + char *msg; + uint16_t text_len; + imaxdiv_t imaxdiv_sec, imaxdiv_usec; + + if (!log_buf_vaddr) { + fprintf(stderr, "Missing the log_buf symbol\n"); + exit(60); } + + if (!log_buf_len_vaddr) { + fprintf(stderr, "Missing the log_bug_len symbol\n"); + exit(61); + } + + if (!log_first_idx_vaddr) { + fprintf(stderr, "Missing the log_first_idx symbol\n"); + exit(62); + } + + if (!log_next_idx_vaddr) { + fprintf(stderr, "Missing the log_next_idx symbol\n"); + exit(63); + } + + if (!log_sz) { + fprintf(stderr, "Missing the struct log size export\n"); + exit(64); + } + + if (log_offset_ts_nsec == UINT64_MAX) { + fprintf(stderr, "Missing the log.ts_nsec offset export\n"); + exit(65); + } + + if (log_offset_len == UINT16_MAX) { + fprintf(stderr, "Missing the log.len offset export\n"); + exit(66); + } + + if (log_offset_text_len == UINT16_MAX) { + fprintf(stderr, "Missing the log.text_len offset export\n"); + exit(67); + } + + log_buf = read_file_pointer(fd, vaddr_to_offset(log_buf_vaddr)); + log_buf_len = read_file_s32(fd, vaddr_to_offset(log_buf_len_vaddr)); + + log_first_idx = read_file_u32(fd, vaddr_to_offset(log_first_idx_vaddr)); + log_next_idx = read_file_u32(fd, vaddr_to_offset(log_next_idx_vaddr)); + + log_buf_offset = vaddr_to_offset(log_buf); + + buf = calloc(1, log_buf_len); + if (!buf) { + fprintf(stderr, "Failed to malloc %d bytes for the logbuf:" + " %s\n", log_buf_len, strerror(errno)); + exit(64); + } + + ret = pread(fd, buf, log_buf_len, log_buf_offset); + if (ret != log_buf_len) { + fprintf(stderr, "Failed to read log buffer of size %d bytes:" + " %s\n", log_buf_len, strerror(errno)); + exit(65); + } + + /* Parse records and write out data at standard output */ + + current_idx = log_first_idx; + len = 0; + while (current_idx != log_next_idx) { + msg = log_from_idx(buf, current_idx); + ts_nsec = struct_val_u64(msg, log_offset_ts_nsec); + imaxdiv_sec = imaxdiv(ts_nsec, 1000000000); + imaxdiv_usec = imaxdiv(imaxdiv_sec.rem, 1000); + + len += sprintf(out_buf + len, "[%5llu.%06llu] ", + (long long unsigned int)imaxdiv_sec.quot, + (long long unsigned int)imaxdiv_usec.quot); + + /* escape non-printable characters */ + text_len = struct_val_u16(msg, log_offset_text_len); + for (i = 0; i < text_len; i++) { + unsigned char c = log_text(msg)[i]; + + if (c < ' ' || c >= 128) + len += sprintf(out_buf + len, "\\x%02x", c); + else + out_buf[len++] = c; + + if (len >= OUT_BUF_SIZE - 16) { + write_to_stdout(out_buf, len); + len = 0; + } + } + + out_buf[len++] = '\n'; + + /* Move to next record */ + current_idx = log_next(buf, current_idx); + } + + if (len) + write_to_stdout(out_buf, len); +} + +static void dump_dmesg(int fd) +{ + if (log_first_idx_vaddr) + dump_dmesg_structured(fd); + else + dump_dmesg_legacy(fd); } int main(int argc, char **argv) |