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Refactor and audit which(1)

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Use the *at functions instead of building paths manually. We do
still have path-building in recurse() and other areas, but the
long-term goal is to rid most interfaces of that for practical
and security reasons.
In this case, it's more or less trivial.

Also, refactor the manpage to be more consistent with the others.

BUGFIX: Return exit status 3 on error.
This commit is contained in:
FRIGN
2015-04-27 20:01:30 +02:00
committed by sin
parent 035e14c516
commit b333176b8c
3 changed files with 65 additions and 47 deletions
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69
which.c
View File

@@ -1,5 +1,7 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
@@ -14,30 +16,34 @@ static int aflag;
static int
which(const char *path, const char *name)
{
char file[PATH_MAX], *p, *s, *ptr;
size_t len;
char *ptr, *p;
size_t i, len;
struct stat st;
int found = 0;
int dirfd, found = 0;
p = ptr = estrdup(path);
for (s = p; (s = strsep(&p, ":")); ) {
if (!s[0])
s = ".";
len = strlen(s);
if (snprintf(file, sizeof(file), "%s%s%s",
s,
len > 0 && s[len - 1] != '/' ? "/" : "",
name) >= sizeof(file))
eprintf("path too long\n");
if (stat(file, &st) == 0 && S_ISREG(st.st_mode) &&
access(file, X_OK) == 0) {
found = 1;
puts(file);
if (!aflag)
break;
ptr = p = enstrdup(3, path);
len = strlen(p);
for (i = 0; i < len + 1; i++) {
if (ptr[i] != ':' && ptr[i] != '\0')
continue;
ptr[i] = '\0';
if ((dirfd = open(p, O_RDONLY, 0)) >= 0) {
if (!fstatat(dirfd, name, &st, 0) &&
S_ISREG(st.st_mode) &&
!faccessat(dirfd, name, X_OK, 0)) {
found = 1;
fputs(p, stdout);
if (i && ptr[i - 1] != '/')
fputc('/', stdout);
puts(name);
if (!aflag) {
close(dirfd);
break;
}
}
close(dirfd);
}
p = ptr + i + 1;
}
free(ptr);
@@ -47,14 +53,14 @@ which(const char *path, const char *name)
static void
usage(void)
{
eprintf("usage: %s [-a] name...\n", argv0);
eprintf("usage: %s [-a] name ...\n", argv0);
}
int
main(int argc, char *argv[])
{
char *path;
int i, found;
int found = 0, foundall = 1;
ARGBEGIN {
case 'a':
@@ -68,13 +74,16 @@ main(int argc, char *argv[])
usage();
if (!(path = getenv("PATH")))
eprintf("$PATH not set\n");
enprintf(3, "$PATH is not set\n");
for (i = 0, found = 0; i < argc; i++) {
if (which(path, argv[i]))
found++;
else
weprintf("%s: Command not found.\n", argv[i]);
for (; *argv; argc--, argv++) {
if (which(path, *argv)) {
found = 1;
} else {
weprintf("%s: command not found.\n", *argv);
foundall = 0;
}
}
return !found ? 2 : found == argc ? 0 : 1;
return found ? foundall ? 0 : 1 : 2;
}