overwrites it. This actually showed up when running under an old
kernel when free() called the madvise() stub which set errno, causing
getcwd() to return EOPNOTSUPP instead of ERANGE.
because it's potentially dangerous (think: symlink races). Move
realpath() back to it's original location, and remove getcwd_physical()
by renaming it back to getcwd() and zapping the original getcwd wrapper.
Noticed by: bde
getcwd() has two off-by-one bugs in FreeBSD-2.0:
1. getcwd(buf, size) fails when the size is just large enough.
2. getcwd(buf + 1, 1) incorrectly succeeds when the current directory
is "/". buf[0] and buf[2] are clobbered.
(I modified Bruce's original patch to return the proper error code
[ERANGE] in the case of #2, but otherwise... -DG)
This program demonstrates the bug:
---
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
int main(void)
{
char buf[5];
int errors;
errors = 0;
if (chdir("/tmp") != 0) {
perror("chdir");
abort();
}
if (getcwd(buf, 5) == NULL) {
perror("oops, getcwd failed for buffer size = size required");
++errors;
}
if (chdir("/") != 0) {
perror("chdir");
abort();
}
buf[0] = 0;
buf[2] = 1;
if (getcwd(buf + 1, 1) != NULL) {
fprintf(stderr,
"oops, getcwd succeeded for buffer size = one too small\n");
++errors;
}
if (buf[0] != 0) {
fprintf(stderr,
"oops, getcwd scribbled on memory before start of buffer\n");
++errors;
}
if (buf[2] != 1) {
fprintf(stderr,
"oops, getcwd scribbled on memory after end of buffer\n");
++errors;
}
exit(errors == 0 ? 0 : 1);
}
