[Revised to handle PR 21283.]
POSIX says:
On some implementations, if buf is a null pointer, getcwd() may obtain
size bytes of memory using malloc(). In this case, the pointer returned
by getcwd() may be used as the argument in a subsequent call to free().
Invoking getcwd() with buf as a null pointer is not recommended in
conforming applications.
This produces an error building GCC with --enable-werror-always:
../../../fixincludes/fixincl.c: In function ‘process’:
../../../fixincludes/fixincl.c:1356:7: error: argument 1 is null but
the corresponding size argument 2 value is 4096 [-Werror=nonnull]
And, at least we've been leaking memory even if getcwd() supports this
non-standard extension.
And, MAXPATHLEN may be not unavailable on certain platform. PATH_MAX is
POSIX, but getcwd() may produce a path with length larger than it. So it's
suggested by POSIX [1] to call getcwd() with progressively larger buffers
until it does not give an [ERANGE] error.
[1]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/getcwd.html
fixincludes/ChangeLog:
PR other/21823
PR bootstrap/80047
* fixincl.c (process): Allocate and deallocate the buffer for
getcwd() progressively.
---
fixincludes/fixincl.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/fixincludes/fixincl.c b/fixincludes/fixincl.c
index 6dba2f6e830..1580c67efec 100644
--- a/fixincludes/fixincl.c
+++ b/fixincludes/fixincl.c
@@ -1353,9 +1353,18 @@ process (void)
if (access (pz_curr_file, R_OK) != 0)
{
int erno = errno;
+ char *buf = NULL;
+ const char *cwd = NULL;
+ for (size_t size = 256; !cwd; size += size)
+ {
+ buf = xrealloc (buf, size);
+ cwd = getcwd (buf, size);
+ if (!cwd && errno != ERANGE)
+ cwd = "the working directory";
+ }
fprintf (stderr, "Cannot access %s from %s\n\terror %d (%s)\n",
- pz_curr_file, getcwd ((char *) NULL, MAXPATHLEN),
- erno, xstrerror (erno));
+ pz_curr_file, cwd, erno, xstrerror (erno));
+ free (buf);
return;
}
--
2.33.1
