#define roundup(x,n) (((x) + ((n) - 1)) & ~((n) - 1)) /* n is power of 2 */
#define min(x,y) (((x) < (y)) ? (x) : (y))
+/* Report a fatal error and exit. */
+static _Noreturn void
+unexec_error (char const *msg)
+{
+ perror (msg);
+ exit (1);
+}
+
+/* Do an lseek and check the result. */
+static void
+check_lseek (int fd, off_t offset, int whence)
+{
+ if (lseek (fd, offset, whence) < 0)
+ unexec_error ("Cannot lseek");
+}
+
/* Save current data space in the file, update header. */
static void
{
/* Write the entire data space out to the file */
if (write (file, auxhdr->exec_dmem, size) != size)
- { perror ("Can't save new data space"); exit (1); }
+ unexec_error ("Can't save new data space");
/* Update the header to reflect the new data size */
auxhdr->exec_dsize = size;
update (auxhdr->exec_dfile);
/* Do for each subspace dictionary entry */
- lseek (file, hdr->subspace_location, 0);
+ check_lseek (file, hdr->subspace_location, 0);
for (i = 0; i < hdr->subspace_total; i++)
{
- if (read (file, &subspace, sizeof (subspace)) != sizeof (subspace))
- { perror ("Can't read subspace record"); exit (1); }
+ ptrdiff_t subspace_size = sizeof subspace;
+ if (read (file, &subspace, subspace_size) != subspace_size)
+ unexec_error ("Can't read subspace record");
/* If subspace has a file location, update it */
if (subspace.initialization_length > 0
&& subspace.file_loc_init_value > location)
{
subspace.file_loc_init_value += offset;
- lseek (file, -sizeof (subspace), 1);
- if (write (file, &subspace, sizeof (subspace)) != sizeof (subspace))
- { perror ("Can't update subspace record"); exit (1); }
+ check_lseek (file, -subspace_size, 1);
+ if (write (file, &subspace, subspace_size) != subspace_size)
+ unexec_error ("Can't update subspace record");
}
}
{
/* Read the header in */
- lseek (file, 0, 0);
+ check_lseek (file, 0, 0);
if (read (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
- { perror ("Couldn't read header from a.out file"); exit (1); }
+ unexec_error ("Couldn't read header from a.out file");
if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC
&& hdr->a_magic != DEMAND_MAGIC)
exit (1);
}
- lseek (file, hdr->aux_header_location, 0);
+ check_lseek (file, hdr->aux_header_location, 0);
if (read (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
- {
- perror ("Couldn't read auxiliary header from a.out file");
- exit (1);
- }
+ unexec_error ("Couldn't read auxiliary header from a.out file");
}
/* Write out the header records into an a.out file. */
hdr->checksum = calculate_checksum (hdr);
/* Write the header back into the a.out file */
- lseek (file, 0, 0);
+ check_lseek (file, 0, 0);
if (write (file, hdr, sizeof (*hdr)) != sizeof (*hdr))
- { perror ("Couldn't write header to a.out file"); exit (1); }
- lseek (file, hdr->aux_header_location, 0);
+ unexec_error ("Couldn't write header to a.out file");
+ check_lseek (file, hdr->aux_header_location, 0);
if (write (file, auxhdr, sizeof (*auxhdr)) != sizeof (*auxhdr))
- { perror ("Couldn't write auxiliary header to a.out file"); exit (1); }
+ unexec_error ("Couldn't write auxiliary header to a.out file");
}
/* Calculate the checksum of a SOM header record. */
{
len = min (size, sizeof (buffer));
if (read (old, buffer, len) != len)
- { perror ("Read failure on a.out file"); exit (1); }
+ unexec_error ("Read failure on a.out file");
if (write (new, buffer, len) != len)
- { perror ("Write failure in a.out file"); exit (1); }
+ unexec_error ("Write failure in a.out file");
}
}
if (write (new, buffer, len) != len) break;
if (len != 0)
- { perror ("Unable to copy the rest of the file"); exit (1); }
+ unexec_error ("Unable to copy the rest of the file");
}
#ifdef DEBUG
it is still executing. If problems occur, everything is still
intact. NOT implemented. */
- /* Open the input and output a.out files */
+ /* Open the input and output a.out files. */
old = emacs_open (old_name, O_RDONLY, 0);
if (old < 0)
- { perror (old_name); exit (1); }
+ unexec_error (old_name);
new = emacs_open (new_name, O_CREAT | O_RDWR | O_TRUNC, 0777);
if (new < 0)
- { perror (new_name); exit (1); }
+ unexec_error (new_name);
- /* Read the old headers */
+ /* Read the old headers. */
read_header (old, &hdr, &auxhdr);
brk_on_dump = (long) sbrk (0);
- /* Decide how large the new and old data areas are */
+ /* Decide how large the new and old data areas are. */
old_size = auxhdr.exec_dsize;
/* I suspect these two statements are separate
to avoid a compiler bug in hpux version 8. */
i = (long) sbrk (0);
new_size = i - auxhdr.exec_dmem;
- /* Copy the old file to the new, up to the data space */
- lseek (old, 0, 0);
+ /* Copy the old file to the new, up to the data space. */
+ check_lseek (old, 0, 0);
copy_file (old, new, auxhdr.exec_dfile);
- /* Skip the old data segment and write a new one */
- lseek (old, old_size, 1);
+ /* Skip the old data segment and write a new one. */
+ check_lseek (old, old_size, 1);
save_data_space (new, &hdr, &auxhdr, new_size);
- /* Copy the rest of the file */
+ /* Copy the rest of the file. */
copy_rest (old, new);
- /* Update file pointers since we probably changed size of data area */
+ /* Update file pointers since we probably changed size of data area. */
update_file_ptrs (new, &hdr, &auxhdr, auxhdr.exec_dfile, new_size-old_size);
- /* Save the modified header */
+ /* Save the modified header. */
write_header (new, &hdr, &auxhdr);
- /* Close the binary file */
+ /* Close the binary file. */
emacs_close (old);
emacs_close (new);
}
HCoop / bpt / emacs.git / blobdiff