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Improve system call support

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This commit is contained in:
Justine Tunney 2021-08-25 21:35:58 -07:00
parent 63b867bd2f
commit 3085ac7837
65 changed files with 900 additions and 544 deletions
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47
libc/x/xreadlinkat.c Normal file
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2021 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/mem/mem.h"
#include "libc/sysv/errfuns.h"
#include "libc/x/x.h"
/**
* Reads symbolic link.
*
* @return nul-terminated string, or null w/ errno
* @see readlinkat()
*/
char *xreadlinkat(int dirfd, const char *path) {
ssize_t rc;
size_t n, c;
char *p, *q;
c = PAGESIZE;
p = xmalloc(c);
if ((rc = readlinkat(dirfd, path, p, c)) != -1) {
if ((n = rc) < c) {
p[n] = 0;
if ((q = realloc(p, n + 1))) p = q;
return p;
} else {
enametoolong();
}
}
free(p);
return 0;
}