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/*******************************************************************/
/* slibtool: a skinny libtool implementation, written in C */
/* Copyright (C) 2016--2021 SysDeer Technologies, LLC */
/* Released under the Standard MIT License; see COPYING.SLIBTOOL. */
/*******************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <unistd.h>
#include "slibtool_driver_impl.h"
#include "slibtool_errinfo_impl.h"
#include "slibtool_symlink_impl.h"
#include "slibtool_readlink_impl.h"
#define SLBT_DEV_NULL_FLAGS (SLBT_DRIVER_ALL_STATIC \
| SLBT_DRIVER_DISABLE_SHARED \
| SLBT_DRIVER_DISABLE_STATIC)
int slbt_create_symlink(
const struct slbt_driver_ctx * dctx,
struct slbt_exec_ctx * ectx,
const char * target,
const char * lnkname,
uint32_t options)
{
int fdcwd;
int fliteral;
int fwrapper;
int fdevnull;
char ** oargv;
const char * slash;
char * ln[5];
char * dotdot;
char tmplnk [PATH_MAX];
char lnkarg [PATH_MAX];
char alnkarg[PATH_MAX];
char atarget[PATH_MAX];
char * suffix = 0;
/* options */
fliteral = (options & SLBT_SYMLINK_LITERAL);
fwrapper = (options & SLBT_SYMLINK_WRAPPER);
fdevnull = (options & SLBT_SYMLINK_DEVNULL);
/* symlink is a placeholder? */
if (fliteral && fdevnull) {
slash = target;
} else if ((dctx->cctx->drvflags & SLBT_DEV_NULL_FLAGS)
&& !strcmp(target,"/dev/null")) {
slash = target;
suffix = ".disabled";
/* target is an absolute path? */
} else if (fliteral) {
slash = target;
/* symlink target contains a dirname? */
} else if ((slash = strrchr(target,'/'))) {
slash++;
/* symlink target is a basename */
} else {
slash = target;
}
/* .la wrapper? */
dotdot = fwrapper ? "../" : "";
/* atarget */
if ((size_t)snprintf(atarget,sizeof(atarget),"%s%s",
dotdot,slash) >= sizeof(atarget))
return SLBT_BUFFER_ERROR(dctx);
/* tmplnk */
if ((size_t)snprintf(tmplnk,sizeof(tmplnk),"%s.symlink.tmp",
lnkname) >= sizeof(tmplnk))
return SLBT_BUFFER_ERROR(dctx);
/* placeholder? */
if (suffix) {
sprintf(alnkarg,"%s%s",lnkname,suffix);
lnkname = alnkarg;
}
/* lnkarg */
strcpy(lnkarg,lnkname);
/* ln argv (fake) */
ln[0] = "ln";
ln[1] = "-s";
ln[2] = atarget;
ln[3] = lnkarg;
ln[4] = 0;
oargv = ectx->argv;
ectx->argv = ln;
/* step output */
if (!(dctx->cctx->drvflags & SLBT_DRIVER_SILENT)) {
if (dctx->cctx->mode == SLBT_MODE_LINK) {
if (slbt_output_link(dctx,ectx)) {
ectx->argv = oargv;
return SLBT_NESTED_ERROR(dctx);
}
} else {
if (slbt_output_install(dctx,ectx)) {
ectx->argv = oargv;
return SLBT_NESTED_ERROR(dctx);
}
}
}
/* restore execution context */
ectx->argv = oargv;
/* fdcwd */
fdcwd = slbt_driver_fdcwd(dctx);
/* create symlink */
if (symlinkat(atarget,fdcwd,tmplnk))
return SLBT_SYSTEM_ERROR(dctx,tmplnk);
return renameat(fdcwd,tmplnk,fdcwd,lnkname)
? SLBT_SYSTEM_ERROR(dctx,lnkname)
: 0;
}
int slbt_symlink_is_a_placeholder(int fdcwd, char * lnkpath)
{
size_t len;
char slink [PATH_MAX];
char target[PATH_MAX];
const char suffix[] = ".disabled";
if ((sizeof(slink)-sizeof(suffix)) < (len=strlen(lnkpath)))
return 0;
memcpy(slink,lnkpath,len);
memcpy(&slink[len],suffix,sizeof(suffix));
return (!slbt_readlinkat(fdcwd,slink,target,sizeof(target)))
&& (!strcmp(target,"/dev/null"));
}
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