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/* ISC license. */
#include <skalibs/sysdeps.h>
#ifdef SKALIBS_HASLINKAT
#include <skalibs/nonposix.h>
#endif
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <skalibs/posixplz.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr.h>
#include <skalibs/stralloc.h>
#include <skalibs/djbunix.h>
#include <skalibs/skamisc.h>
#define USAGE "s6-ln [ -n ] [ -s ] [ -f ] [ -L ] [ -P ] src... dest"
#define LN_SUFFIX ":s6-ln:XXXXXX"
#ifdef SKALIBS_HASLINKAT
static int linknoderef (char const *old, char const *new)
{
return linkat(AT_FDCWD, old, AT_FDCWD, new, 0) ;
}
static int linkderef (char const *old, char const *new)
{
return linkat(AT_FDCWD, old, AT_FDCWD, new, AT_SYMLINK_FOLLOW) ;
}
#else /* can't implement SUSv4, default to link */
# define linknoderef link
# define linkderef link
#endif
static int ln_doit (char const *old, char const *new, link_func_ref mylink, int force)
{
if ((*mylink)(old, new) == -1)
{
if (!force || errno != EEXIST)
{
strerr_warnwu5sys("make a link", " from ", new, " to ", old) ;
return 1 ;
}
{
size_t newlen = strlen(new) ;
char fn[newlen + sizeof(LN_SUFFIX)] ;
memcpy(fn, new, newlen) ;
memcpy(fn + newlen, LN_SUFFIX, sizeof(LN_SUFFIX)) ;
if (mklinktemp(old, fn, mylink) == -1)
{
strerr_warnwu3sys("make a link", " to ", old) ;
return 1 ;
}
if (rename(fn, new) == -1)
{
unlink_void(fn) ;
strerr_warnwu2sys("atomically replace ", new) ;
return 1 ;
}
/* if old == new, rename() didn't remove fn */
unlink_void(fn) ;
}
}
return 0 ;
}
int main (int argc, char const *const *argv)
{
link_func_ref mylink = &link ; /* default to system behaviour */
int force = 0 ;
int nodir = 0 ;
PROG = "s6-ln" ;
{
subgetopt l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "nsfLP", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'n' : nodir = 1 ; break ;
case 's': mylink = &symlink ; break ;
case 'f': force = 1 ; break ;
case 'L': if (mylink != &symlink) mylink = &linkderef ; break ;
case 'P': if (mylink != &symlink) mylink = &linknoderef ; break ;
default : strerr_dieusage(100, USAGE) ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (argc < 2) strerr_dieusage(100, USAGE) ;
if (argc > 2)
{
stralloc sa = STRALLOC_ZERO ;
unsigned int i = 0 ;
int e = 0 ;
size_t base ;
if (!stralloc_cats(&sa, argv[argc-1]) || !stralloc_catb(&sa, "/", 1))
strerr_diefu1sys(111, "stralloc_cats") ;
base = sa.len ;
for (; i < (unsigned int)(argc-1) ; i++)
{
sa.len = base ;
if (!sabasename(&sa, argv[i], strlen(argv[i])))
{
strerr_warnwu1sys("sabasename") ;
e++ ;
continue ;
}
if (!stralloc_0(&sa))
{
strerr_warnwu1sys("stralloc_0") ;
e++ ;
continue ;
}
e += ln_doit(argv[i], sa.s, mylink, force) ;
}
return e ;
}
{
struct stat st ;
if (nodir ? lstat(argv[1], &st) : stat(argv[1], &st) < 0)
{
if (errno != ENOENT) strerr_diefu2sys(111, "stat ", argv[1]) ;
return ln_doit(argv[0], argv[1], mylink, force) ;
}
if (!S_ISDIR(st.st_mode))
return ln_doit(argv[0], argv[1], mylink, force) ;
}
{
stralloc sa = STRALLOC_ZERO ;
if (!stralloc_cats(&sa, argv[1])
|| !stralloc_catb(&sa, "/", 1)
|| !sabasename(&sa, argv[0], strlen(argv[0]))
|| !stralloc_0(&sa))
strerr_diefu1sys(111, "stralloc_catb") ;
return ln_doit(argv[0], sa.s, mylink, force) ;
}
}
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