Add ln

6 files changed, 140 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 7376893..c022798 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,7 @@ src/include/shh-portable-utils/config.h
 /dirname
 /false
 /link
+/ln
 /tee
 /true
 /uname
diff --git a/package/deps.mak b/package/deps.mak
index fa96b0a..5e42f73 100644
--- a/package/deps.mak
+++ b/package/deps.mak
@@ -12,6 +12,7 @@ src/shh-portable-utils/cut.o src/shh-portable-utils/cut.lo: src/shh-portable-uti
 src/shh-portable-utils/dirname.o src/shh-portable-utils/dirname.lo: src/shh-portable-utils/dirname.c
 src/shh-portable-utils/false.o src/shh-portable-utils/false.lo: src/shh-portable-utils/false.c
 src/shh-portable-utils/link.o src/shh-portable-utils/link.lo: src/shh-portable-utils/link.c
+src/shh-portable-utils/ln.o src/shh-portable-utils/ln.lo: src/shh-portable-utils/ln.c
 src/shh-portable-utils/shhgetln.o src/shh-portable-utils/shhgetln.lo: src/shh-portable-utils/shhgetln.c src/shh-portable-utils/shhfuncs.h
 src/shh-portable-utils/tee.o src/shh-portable-utils/tee.lo: src/shh-portable-utils/tee.c
 src/shh-portable-utils/true.o src/shh-portable-utils/true.lo: src/shh-portable-utils/true.c
@@ -36,6 +37,8 @@ false: EXTRA_LIBS :=
 false: src/shh-portable-utils/false.o
 link: EXTRA_LIBS := -lskarnet
 link: src/shh-portable-utils/link.o
+ln: EXTRA_LIBS := -lskarnet
+ln: src/shh-portable-utils/ln.o
 tee: EXTRA_LIBS := -lskarnet
 tee: src/shh-portable-utils/tee.o
 true: EXTRA_LIBS :=
diff --git a/package/modes b/package/modes
index 0b9026f..3cabd5f 100644
--- a/package/modes
+++ b/package/modes
@@ -7,6 +7,7 @@ cut			0755
 dirname     0755
 false		0755
 link        0755
+ln          0755
 tee         0755
 true		0755
 uniq		0755
diff --git a/package/targets.mak b/package/targets.mak
index b4e7c08..237cfb4 100644
--- a/package/targets.mak
+++ b/package/targets.mak
@@ -8,6 +8,7 @@ cut \
 dirname \
 false \
 link \
+ln \
 tee \
 true \
 uname \
diff --git a/src/shh-portable-utils/deps-exe/ln b/src/shh-portable-utils/deps-exe/ln
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/shh-portable-utils/deps-exe/ln
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/shh-portable-utils/ln.c b/src/shh-portable-utils/ln.c
new file mode 100644
index 0000000..54d34f6
--- /dev/null
+++ b/src/shh-portable-utils/ln.c
@@ -0,0 +1,133 @@
+#include <string.h>
+#include <errno.h>
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <skalibs/strerr2.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/stralloc.h>
+
+#define USAGE "ln [-fs] [-L|-P] source_file target_file |  ln [-fs] [-L|-P] source_file... target_dir"
+
+int make_link(char const*, char const*, int, int, int);
+
+int main(int argc, char const *const *argv)
+{
+    struct stat st;
+    int result;
+    int failure = 0;
+    int create_symlink = 0;
+    int force_unlink = 0;
+    int flag = 0;
+    stralloc s = STRALLOC_ZERO;
+    subgetopt l = SUBGETOPT_ZERO;
+
+    PROG = "ln";
+
+    for (;;) {
+        int opt = subgetopt_r(argc, argv, "fsLP", &l);
+        if (opt == -1)
+            break;
+        switch (opt) {
+            case 'f':
+                force_unlink = 1;
+                break;
+            case 's':
+                create_symlink = 1;
+                break;
+            case 'L':
+                flag = AT_SYMLINK_FOLLOW;
+                break;
+            case 'P':
+                flag = 0;
+                break;
+            default:
+                strerr_dieusage(100, USAGE);
+        }
+    }
+    argc -= l.ind;
+    argv += l.ind;
+
+    if (argc < 2)
+        strerr_dieusage(100, USAGE);
+
+    result = lstat(argv[argc - 1], &st);
+    if (result == -1 && errno != ENOENT) {
+        strerr_diefu2sys(111, "lstat ", argv[argc - 1]);
+    }
+
+    if (result == -1 || (!S_ISDIR(st.st_mode))) {
+        if (argc != 2)
+            strerr_dieusage(100, USAGE);
+        if (!S_ISDIR(st.st_mode)) {
+            failure = failure || make_link(argv[0], argv[1], create_symlink,
+                                           force_unlink, flag);
+        }
+        return failure ? 111 : 0;
+    }
+
+    for (size_t i = 0; i < argc - 1; i++) {
+        s.len = 0;
+        if (!stralloc_cats(&s, argv[argc - 1])) {
+            strerr_warnwu2sys("Build target filename for ", argv[i]);
+            failure = 1;
+            continue;
+        }
+        if (!stralloc_append(&s, '/'))  {
+            strerr_warnwu2sys("Build target filename for ", argv[i]);
+            failure = 1;
+            continue;
+        }
+        if (!sabasename(&s, argv[i], strlen(argv[i]))) {
+            strerr_warnwu2sys("Build target filename for ", argv[i]);
+            failure = 1;
+            continue;
+        }
+        if (!stralloc_0(&s)) {
+            strerr_warnwu2sys("Build target filename for ", argv[i]);
+            failure = 1;
+            continue;
+        }
+
+        failure = failure || make_link(argv[i], s.s, create_symlink,
+                                       force_unlink, flag);
+    }
+
+    return failure ? 111 : 0;
+}
+
+int make_link(char const *src, char const *target, int create_symlink,
+              int force_unlink, int flag)
+{
+    int result;
+    if (create_symlink)
+        result = symlink(src, target);
+    else
+        result = linkat(AT_FDCWD, src, AT_FDCWD, target, flag);
+
+    if (result == -1) {
+        if (!force_unlink || errno != EEXIST) {
+            strerr_warnwu4sys("create link ", target, " to ", src);
+            return 1;
+        }
+        if (unlink(target) == -1) {
+            strerr_warnwu2sys("remove ", target);
+            return 1;
+        }
+
+        if (create_symlink)
+            result = symlink(src, target);
+        else
+            result = linkat(AT_FDCWD, src, AT_FDCWD, target, flag);
+
+        if (result == -1) {
+            strerr_warnwu4sys("create link ", target, " to ", src);
+            return 1;
+        }
+    }
+    return 0;
+}