diff options
Diffstat (limited to 'scripts/recordmcount.c')
| -rw-r--r-- | scripts/recordmcount.c | 137 |
1 files changed, 113 insertions, 24 deletions
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index 698768bdc581..e167592793a7 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -48,12 +48,17 @@ static int fd_map; /* File descriptor for file being modified. */ static int mmap_failed; /* Boolean flag. */ -static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ static char gpfx; /* prefix for global symbol name (sometimes '_') */ static struct stat sb; /* Remember .st_size, etc. */ static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */ static const char *altmcount; /* alternate mcount symbol name */ static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */ +static void *file_map; /* pointer of the mapped file */ +static void *file_end; /* pointer to the end of the mapped file */ +static int file_updated; /* flag to state file was changed */ +static void *file_ptr; /* current file pointer location */ +static void *file_append; /* added to the end of the file */ +static size_t file_append_size; /* how much is added to end of file */ /* setjmp() return values */ enum { @@ -67,10 +72,14 @@ static void cleanup(void) { if (!mmap_failed) - munmap(ehdr_curr, sb.st_size); + munmap(file_map, sb.st_size); else - free(ehdr_curr); - close(fd_map); + free(file_map); + file_map = NULL; + free(file_append); + file_append = NULL; + file_append_size = 0; + file_updated = 0; } static void __attribute__((noreturn)) @@ -92,12 +101,22 @@ succeed_file(void) static off_t ulseek(int const fd, off_t const offset, int const whence) { - off_t const w = lseek(fd, offset, whence); - if (w == (off_t)-1) { - perror("lseek"); + switch (whence) { + case SEEK_SET: + file_ptr = file_map + offset; + break; + case SEEK_CUR: + file_ptr += offset; + break; + case SEEK_END: + file_ptr = file_map + (sb.st_size - offset); + break; + } + if (file_ptr < file_map) { + fprintf(stderr, "lseek: seek before file\n"); fail_file(); } - return w; + return file_ptr - file_map; } static size_t @@ -114,12 +133,38 @@ uread(int const fd, void *const buf, size_t const count) static size_t uwrite(int const fd, void const *const buf, size_t const count) { - size_t const n = write(fd, buf, count); - if (n != count) { - perror("write"); - fail_file(); + size_t cnt = count; + off_t idx = 0; + + file_updated = 1; + + if (file_ptr + count >= file_end) { + off_t aoffset = (file_ptr + count) - file_end; + + if (aoffset > file_append_size) { + file_append = realloc(file_append, aoffset); + file_append_size = aoffset; + } + if (!file_append) { + perror("write"); + fail_file(); + } + if (file_ptr < file_end) { + cnt = file_end - file_ptr; + } else { + cnt = 0; + idx = aoffset - count; + } } - return n; + + if (cnt) + memcpy(file_ptr, buf, cnt); + + if (cnt < count) + memcpy(file_append + idx, buf + cnt, count - cnt); + + file_ptr += count; + return count; } static void * @@ -192,9 +237,7 @@ static int make_nop_arm64(void *map, size_t const offset) */ static void *mmap_file(char const *fname) { - void *addr; - - fd_map = open(fname, O_RDWR); + fd_map = open(fname, O_RDONLY); if (fd_map < 0 || fstat(fd_map, &sb) < 0) { perror(fname); fail_file(); @@ -203,15 +246,58 @@ static void *mmap_file(char const *fname) fprintf(stderr, "not a regular file: %s\n", fname); fail_file(); } - addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, - fd_map, 0); + file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, + fd_map, 0); mmap_failed = 0; - if (addr == MAP_FAILED) { + if (file_map == MAP_FAILED) { mmap_failed = 1; - addr = umalloc(sb.st_size); - uread(fd_map, addr, sb.st_size); + file_map = umalloc(sb.st_size); + uread(fd_map, file_map, sb.st_size); + } + close(fd_map); + + file_end = file_map + sb.st_size; + + return file_map; +} + +static void write_file(const char *fname) +{ + char tmp_file[strlen(fname) + 4]; + size_t n; + + if (!file_updated) + return; + + sprintf(tmp_file, "%s.rc", fname); + + /* + * After reading the entire file into memory, delete it + * and write it back, to prevent weird side effects of modifying + * an object file in place. + */ + fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode); + if (fd_map < 0) { + perror(fname); + fail_file(); + } + n = write(fd_map, file_map, sb.st_size); + if (n != sb.st_size) { + perror("write"); + fail_file(); + } + if (file_append_size) { + n = write(fd_map, file_append, file_append_size); + if (n != file_append_size) { + perror("write"); + fail_file(); + } + } + close(fd_map); + if (rename(tmp_file, fname) < 0) { + perror(fname); + fail_file(); } - return addr; } /* w8rev, w8nat, ...: Handle endianness. */ @@ -318,7 +404,6 @@ do_file(char const *const fname) Elf32_Ehdr *const ehdr = mmap_file(fname); unsigned int reltype = 0; - ehdr_curr = ehdr; w = w4nat; w2 = w2nat; w8 = w8nat; @@ -441,6 +526,7 @@ do_file(char const *const fname) } } /* end switch */ + write_file(fname); cleanup(); } @@ -493,11 +579,14 @@ main(int argc, char *argv[]) case SJ_SETJMP: /* normal sequence */ /* Avoid problems if early cleanup() */ fd_map = -1; - ehdr_curr = NULL; mmap_failed = 1; + file_map = NULL; + file_ptr = NULL; + file_updated = 0; do_file(file); break; case SJ_FAIL: /* error in do_file or below */ + fprintf(stderr, "%s: failed\n", file); ++n_error; break; case SJ_SUCCEED: /* premature success */ |