On Tue, 15 Dec 2015 22:44:14 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> Here's v2.
>
Here's v3. My tests found a bug in the code where I used snprintf()
when I should have used sprintf().
-- Steve
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 91705ef30402..80be4ce4ad9f 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, 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();
@@ -203,29 +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);
}
- if (sb.st_nlink != 1) {
- /* file is hard-linked, break the hard link */
- close(fd_map);
- if (unlink(fname) < 0) {
+ 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) {
+ 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_CREAT, sb.st_mode);
+ if (fd_map < 0) {
perror(fname);
fail_file();
}
- fd_map = open(fname, O_RDWR | O_CREAT, sb.st_mode);
- if (fd_map < 0) {
+ 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();
}
- uwrite(fd_map, addr, sb.st_size);
}
- return addr;
+
}
/* w8rev, w8nat, ...: Handle endianness. */
@@ -332,7 +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;
@@ -455,6 +526,7 @@ do_file(char const *const fname)
}
} /* end switch */
+ write_file(fname);
cleanup();
}
@@ -507,11 +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 */
+ sprintf("%s: failed\n", file);
++n_error;
break;
case SJ_SUCCEED: /* premature success */
--
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