git: 3728c4d31495 - stable/13 - diff: fix incorrectly displaying files as duplicates

[Baptiste Daroussin]

The branch stable/13 has been updated by bapt:

URL: https://cgit.FreeBSD.org/src/commit/?id=3728c4d3149553967532a97254737bdb2cd92417

commit 3728c4d3149553967532a97254737bdb2cd92417
Author:     Jamie Landeg-Jones <jamie at catflap.org>
AuthorDate: 2021-01-25 17:42:26 +0000
Commit:     Baptiste Daroussin <bapt at FreeBSD.org>
CommitDate: 2021-02-01 13:05:25 +0000

    diff: fix incorrectly displaying files as duplicates
    
    When diff hits certain access errors, function diffreg() shows the error
    message, and then returns to the calling function, which calls
    print_status() with the return value.
    
    However, in these cases, the return value isn't changed from the initial
    default value of D_SAME.
    
    Normally, print_status() with a value of D_SAME does nothing, so this
    works out ok, however, if the "-s" flag is set, a message is displayed
    showing identicality:
    
    case D_SAME:
                    if (sflag)
                            printf("Files %s%s and %s%s are identical\n",                                                                                                       path1, entry, path2, entry);
                    break;
    
    This then produces such results as:
    
    % diff  -s /COPYRIGHT /var/run/rpcbind.sock
    diff: /var/run/rpcbind.sock: Operation not supported
    Files /COPYRIGHT and /var/run/rpcbind.sock are identical
    
    % diff  -s /COPYRIGHT /etc/master.passwd
    diff: /etc/master.passwd: Permission denied
    Files /COPYRIGHT and /etc/master.passwd are identical
    
    Create a D_ERROR status which is returned in such cases, and
    print_status() then deals with that status seperately from D_SAME
    
    PR:             252614
    MFC after:      1 week
    
    (cherry picked from commit fefb3c46a80fdde6f307e73a2b5b5aed806df1ce)
---
 usr.bin/diff/diff.c    | 2 ++
 usr.bin/diff/diff.h    | 1 +
 usr.bin/diff/diffreg.c | 5 +++++
 3 files changed, 8 insertions(+)

diff --git a/usr.bin/diff/diff.c b/usr.bin/diff/diff.c
index 0e46b96f9667..1bad6226f49d 100644
--- a/usr.bin/diff/diff.c
+++ b/usr.bin/diff/diff.c
@@ -511,6 +511,8 @@ print_status(int val, char *path1, char *path2, const char *entry)
 		printf("File %s%s is not a regular file or directory and was skipped\n",
 		    path2, entry);
 		break;
+	case D_ERROR:
+		break;
 	}
 }
 
diff --git a/usr.bin/diff/diff.h b/usr.bin/diff/diff.h
index 30387610fc19..1974b5cc08d6 100644
--- a/usr.bin/diff/diff.h
+++ b/usr.bin/diff/diff.h
@@ -83,6 +83,7 @@
 #define	D_MISMATCH2	4	/* path1 was a file, path2 a dir */
 #define	D_SKIPPED1	5	/* path1 was a special file */
 #define	D_SKIPPED2	6	/* path2 was a special file */
+#define	D_ERROR		7	/* A file access error occurred */
 
 struct excludes {
 	char *pattern;
diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c
index 7d2b20b43def..4e887ab27c7b 100644
--- a/usr.bin/diff/diffreg.c
+++ b/usr.bin/diff/diffreg.c
@@ -299,6 +299,7 @@ diffreg(char *file1, char *file2, int flags, int capsicum)
 			if ((f1 = opentemp(file1)) == NULL ||
 			    fstat(fileno(f1), &stb1) == -1) {
 				warn("%s", file1);
+				rval = D_ERROR;
 				status |= 2;
 				goto closem;
 			}
@@ -309,6 +310,7 @@ diffreg(char *file1, char *file2, int flags, int capsicum)
 	}
 	if (f1 == NULL) {
 		warn("%s", file1);
+		rval = D_ERROR;
 		status |= 2;
 		goto closem;
 	}
@@ -320,6 +322,7 @@ diffreg(char *file1, char *file2, int flags, int capsicum)
 			if ((f2 = opentemp(file2)) == NULL ||
 			    fstat(fileno(f2), &stb2) == -1) {
 				warn("%s", file2);
+				rval = D_ERROR;
 				status |= 2;
 				goto closem;
 			}
@@ -330,6 +333,7 @@ diffreg(char *file1, char *file2, int flags, int capsicum)
 	}
 	if (f2 == NULL) {
 		warn("%s", file2);
+		rval = D_ERROR;
 		status |= 2;
 		goto closem;
 	}
@@ -365,6 +369,7 @@ diffreg(char *file1, char *file2, int flags, int capsicum)
 		break;
 	default:
 		/* error */
+		rval = D_ERROR;
 		status |= 2;
 		goto closem;
 	}