diff --git a/utils/.gitignore b/utils/.gitignore
index f21119ee..a3934a5a 100644
--- a/utils/.gitignore
+++ b/utils/.gitignore
@@ -25,3 +25,4 @@ tail
type
mkdir
rmdir
+which
diff --git a/utils/Makefile b/utils/Makefile
index e9e6d5d1..4dec77da 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -41,6 +41,7 @@ tail \
type \
mkdir \
rmdir \
+which \
INSTALLBINARIES:=$(addprefix $(DESTDIR)$(BINDIR)/,$(BINARIES))
diff --git a/utils/which.cpp b/utils/which.cpp
new file mode 100755
index 00000000..e9020300
--- /dev/null
+++ b/utils/which.cpp
@@ -0,0 +1,169 @@
+/*******************************************************************************
+
+ Copyright(C) Jonas 'Sortie' Termansen 2012.
+
+ This program is free software: you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the Free
+ Software Foundation, either version 3 of the License, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ You should have received a copy of the GNU General Public License along with
+ this program. If not, see .
+
+ which.cpp
+ Locate a program in the PATH.
+
+*******************************************************************************/
+
+#include
+#include
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#if !defined(VERSIONSTR)
+#define VERSIONSTR "unknown version"
+#endif
+
+bool Which(const char* cmd, const char* path, bool all)
+{
+ if ( strchr(cmd, '/') )
+ {
+ struct stat st;
+ if ( stat(path, &st) )
+ {
+ printf("%s\n", cmd);
+ return true;
+ }
+ return false;
+ }
+
+ // Sortix doesn't support that the empty string means current directory.
+ bool found = false;
+ char* dirname = NULL;
+ while ( *path )
+ {
+ if ( dirname ) { free(dirname); dirname = NULL; }
+ size_t len = strcspn(path, ":");
+ if ( !len ) { path++; continue; }
+ dirname = (char*) malloc((len+1) * sizeof(char));
+ if ( !dirname )
+ error(1, errno, "malloc");
+ memcpy(dirname, path, len * sizeof(char));
+ dirname[len] = '\0';
+ path += len + 1;
+ int dirfd = open(dirname, O_RDONLY | O_DIRECTORY);
+ if ( dirfd < 0 )
+ {
+ if ( errno == EACCES )
+ error(1, errno, "%s", dirname);
+ // TODO: May be a security concern to continue;
+ if ( errno == ENOENT )
+ continue;
+ continue;
+ }
+ struct stat st;
+ int ret = fstatat(dirfd, cmd, &st, 0);
+ if ( ret != 0 )
+ continue;
+ printf("%s/%s\n", dirname, cmd);
+ found = true;
+ if ( !all )
+ break;
+ }
+ free(dirname);
+ return found;
+}
+
+void Usage(FILE* fp, const char* argv0)
+{
+ fprintf(fp, "Usage: %s [-a] FILENAME...\n", argv0);
+ fprintf(fp, "Locate a program in the PATH.\n");
+}
+
+void Help(FILE* fp, const char* argv0)
+{
+ Usage(fp, argv0);
+}
+
+void Version(FILE* fp, const char* argv0)
+{
+ fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+ fprintf(fp, "License GPLv3+: GNU GPL version 3 or later .\n");
+ fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+ fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+ const char* argv0 = argv[0];
+ bool all = false;
+ for ( int i = 1; i < argc; i++ )
+ {
+ const char* arg = argv[i];
+ if ( arg[0] != '-' )
+ continue;
+ argv[i] = NULL;
+ if ( !strcmp(arg, "--") )
+ break;
+ if ( arg[1] != '-' )
+ for ( size_t i = 1; arg[i]; i++ )
+ switch ( arg[i] )
+ {
+ case 'a': all = true; break;
+ default:
+ fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, arg[i]);
+ Usage(stderr, argv0);
+ exit(1);
+ }
+ else if ( !strcmp(arg, "--help") ) { Help(stdout, argv0); exit(0); }
+ else if ( !strcmp(arg, "--usage") ) { Usage(stdout, argv0); exit(0); }
+ else if ( !strcmp(arg, "--version") ) { Version(stdout, argv0); exit(0); }
+ else
+ {
+ fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+ Usage(stderr, argv0);
+ exit(1);
+ }
+ }
+
+ int num_args = 0;
+ for ( int i = 1; i < argc; i++ )
+ if ( argv[i] )
+ num_args++;
+
+ if ( !num_args )
+ {
+ fprintf(stderr, "%s: missing operand\n", argv0);
+ exit(1);
+ }
+
+ const char* path = getenv("PATH");
+ if ( !path )
+ {
+ fprintf(stderr, "%s: PATH variable is not set\n", argv0);
+ exit(1);
+ }
+
+ bool success = true;
+ for ( int i = 1; i < argc; i++ )
+ {
+ const char* arg = argv[i];
+ if ( !arg )
+ continue;
+ if ( !Which(arg, path, all) )
+ success = false;
+ }
+
+ return success ? 0 : 1;
+}