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#include <unistd.h>
#include "alloc.h"
#include "error.h"
#include "stralloc.h"
#include "str.h"
#include "byte.h"
#include "env.h"
#include "pathexec.h"
/**
@file pathexec.c
@author djb
@source ucspi-tcp, ucspi-ssl
@brief populate environment after fork
*/
static stralloc plus;
static stralloc tmp;
int pathexec_env(const char *s,const char *t)
{
if (!s) return 1;
if (!stralloc_copys(&tmp,s)) return 0;
if (t) {
if (!stralloc_cats(&tmp,"=")) return 0;
if (!stralloc_cats(&tmp,t)) return 0;
}
if (!stralloc_0(&tmp)) return 0;
return stralloc_cat(&plus,&tmp);
}
int pathexec_multienv(stralloc *sa)
{
if (!sa) return 1;
return stralloc_cat(&plus,sa);
}
void pathexec(char * const *argv)
{
char **e;
unsigned int elen;
unsigned int i;
unsigned int j;
unsigned int split;
unsigned int t;
if (!stralloc_cats(&plus,"")) return;
elen = 0;
for (i = 0; environ[i]; ++i)
++elen;
for (i = 0; i < plus.len; ++i)
if (!plus.s[i])
++elen;
e = (char **) alloc((elen + 1) * sizeof(char *));
if (!e) return;
elen = 0;
for (i = 0; environ[i]; ++i)
e[elen++] = environ[i];
j = 0;
for (i = 0; i < plus.len; ++i)
if (!plus.s[i]) {
split = str_chr(plus.s + j,'=');
for (t = 0; t < elen; ++t)
if (byte_equal(plus.s + j,split,e[t]))
if (e[t][split] == '=') {
--elen;
e[t] = e[elen];
break;
}
if (plus.s[j + split])
e[elen++] = plus.s + j;
j = i + 1;
}
e[elen] = 0;
pathexec_run(*argv,argv,e);
alloc_free(e);
}
void pathexec_run(const char *file,char *const *argv,char *const *envp)
{
char *path;
unsigned int split;
int savederrno;
if (file[str_chr(file,'/')]) {
execve(file,argv,envp);
return;
}
path = env_get("PATH");
if (!path) path = "/bin:/usr/bin";
savederrno = 0;
for (;;) {
split = str_chr(path,':');
if (!stralloc_copyb(&tmp,path,split)) return;
if (!split)
if (!stralloc_cats(&tmp,".")) return;
if (!stralloc_cats(&tmp,"/")) return;
if (!stralloc_cats(&tmp,file)) return;
if (!stralloc_0(&tmp)) return;
execve(tmp.s,argv,envp);
if (errno != ENOENT) {
savederrno = errno;
if ((errno != EACCES) && (errno != EPERM) && (errno != EISDIR)) return;
}
if (!path[split]) {
if (savederrno) errno = savederrno;
return;
}
path += split;
path += 1;
}
}
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