coreutils

logname: Add POSIX logname

Diffstat

4 files changed, 62 insertions, 3 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9832ae3..aae602b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,6 +16,7 @@ ADD_EXECUTABLE(dirname  ${CMAKE_SOURCE_DIR}/src/dirname.c)
 ADD_EXECUTABLE(echo     ${CMAKE_SOURCE_DIR}/src/echo.c)
 ADD_EXECUTABLE(false    ${CMAKE_SOURCE_DIR}/src/false.c)
 ADD_EXECUTABLE(link     ${CMAKE_SOURCE_DIR}/src/link.c)
+ADD_EXECUTABLE(logname  ${CMAKE_SOURCE_DIR}/src/logname.c)
 ADD_EXECUTABLE(mkdir    ${CMAKE_SOURCE_DIR}/src/mkdir.c)
 ADD_EXECUTABLE(rmdir    ${CMAKE_SOURCE_DIR}/src/rmdir.c)
 ADD_EXECUTABLE(tee      ${CMAKE_SOURCE_DIR}/src/tee.c)
diff --git a/README.md b/README.md
index e913ffd..496bfca 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,9 @@
-# OMKOV Core Utilities
+# OMKOV coreutils
 
 > OMKOV implementations of core software utilities
 
-OMKOV Core Utilities (coreutils) implements many basic software utilities
-commonly found on UNIX-like systems.
+OMKOV coreutils implements many basic software utilities commonly found on
+UNIX-like systems.
 
 ## Utilities
 
@@ -15,6 +15,7 @@ commonly found on UNIX-like systems.
 | echo             | Write arguments to standard output       | POSIX    |
 | false            | Return false value                       | POSIX    |
 | link             | Create a link to a file                  | POSIX    |
+| logname          | Return the user's login name             | POSIX    |
 | mkdir            | Make directories                         | POSIX    |
 | rmdir            | Remove directories                       | POSIX    |
 | tee              | Duplicate standard input                 | POSIX    |
diff --git a/man/logname.1 b/man/logname.1
new file mode 100644
index 0000000..91b23bb
--- /dev/null
+++ b/man/logname.1
@@ -0,0 +1,24 @@
+.TH LOGNAME 1 2020-06-26 "OMKOV coreutils" "General Commands Manual"
+.SH NAME
+logname \(em return the user's login name
+.SH SYNOPSYS
+\fBlogname\fR
+.SH DESCRIPTION
+Print the user's login name to standard output.
+.SH EXIT STATUS
+The following exit values will be returned:
+.TP
+\ 0
+Successful completion.
+.TP
+>0
+An error occurred.
+.SH STANDARDS
+The \fIlogname\fR utility is compliant with the IEEE Std 1003.2-1992 ("POSIX.2")
+specification.
+.SH COPYRIGHT
+.nf
+Copyright (C) 2020, Jakob Wakeling
+All rights reserved.
+OMKOV Public Domain Licence (https://www.omkov.net/OLPD)
+.fi
diff --git a/src/logname.c b/src/logname.c
new file mode 100644
index 0000000..ed4f2cb
--- /dev/null
+++ b/src/logname.c
@@ -0,0 +1,33 @@
+// logname.c, version 1.0.0
+// OMKOV coreutils implementation of POSIX logname
+// Copyright (C) 2020, Jakob Wakeling
+// All rights reserved.
+
+/*
+OMKOV Public Domain Licence, version 1.0
+
+Permission is hereby granted to deal with this software and its associated
+documentation files without restriction.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT
+HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE.
+*/
+
+#include "error.h"
+
+#include <unistd.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+int main(int argc, char *argv[]) { (void)argc;
+	register char *login = getlogin();
+	if (!login) { error(1, "%s: %s", argv[0], serrno); }
+	else { fputs(login, stdout); fputc('\n', stdout); }
+	return 0;
+}