sed: fix very obscure case of escaped newline in sed command

(needed for uclibc build, btw). Add testcase for it.

2 files changed, 33 insertions, 12 deletions

diff --git a/editors/sed.c b/editors/sed.c
index c434eee1b..f7f22f750 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -1175,21 +1175,38 @@ restart:
 }
 
 /* It is possible to have a command line argument with embedded
-   newlines.  This counts as multiple command lines. */
+ * newlines.  This counts as multiple command lines.
+ * However, newline can be escaped: 's/e/z\<newline>z/'
+ * We check for this.
+ */
 
 static void add_cmd_block(char *cmdstr)
 {
-        int go = 1;
-        char *temp = xstrdup(cmdstr), *temp2 = temp;
-
-        while (go) {
-                int len = strcspn(temp2, "\n");
-                if (!temp2[len]) go = 0;
-                else temp2[len] = 0;
-                add_cmd(temp2);
-                temp2 += len+1;
-        }
-        free(temp);
+        char *sv, *eol;
+
+        cmdstr = sv = xstrdup(cmdstr);
+        do {
+                eol = strchr(cmdstr, '\n');
+ next:
+                if (eol) {
+                        /* Count preceding slashes */
+                        int slashes = 0;
+                        char *sl = eol;
+
+                        while (sl != cmdstr && *--sl == '\\')
+                                slashes++;
+                        /* Odd number of preceding slashes - newline is escaped */
+                        if (slashes & 1) {
+                                strcpy(eol-1, eol);
+                                eol = strchr(eol, '\n');
+                                goto next;
+                        }
+                        *eol = '\0';
+                }
+                add_cmd(cmdstr);
+                cmdstr = eol + 1;
+        } while (eol);
+        free(sv);
 }
 
 static void add_cmds_link(llist_t *opt_e)
diff --git a/testsuite/sed.tests b/testsuite/sed.tests
index 9576b6c4b..a054de6d7 100755
--- a/testsuite/sed.tests
+++ b/testsuite/sed.tests
@@ -146,6 +146,10 @@ rm outputw
 testing "sed trailing NUL" \
         "sed 's/i/z/' input -" \
         "a\0b\0\nc" "a\0b\0" "c"
+testing "sed escaped newline in command" \
+        "sed 's/a/z\\
+z/' input" \
+        "z\nz" "a" ""
 
 # Test end-of-file matching behavior