psuedo: Add tracking of linked files for fds

Where files are link()'d and one is unlink()'d, pseudo's fd mappings
can become confused. Add a patch to try and improve this for the common
usecases we see.

(From OE-Core rev: 09da51d69e1ead6dc7b41034f1dee05e1c98078b)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 9ce621fa2099608ca0ccbb8420b31d71cdd7b00e)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 156 insertions, 0 deletions

diff --git a/meta/recipes-devtools/pseudo/files/track_link_fds.patch b/meta/recipes-devtools/pseudo/files/track_link_fds.patch
new file mode 100644
index 0000000000..a3a9eb3f23
--- /dev/null
+++ b/meta/recipes-devtools/pseudo/files/track_link_fds.patch
@@ -0,0 +1,155 @@
+Consider what happens if a program does:
+
+fd = fopen("A")
+link("A", "B")
+unlink("A")
+fchown(fd)
+
+Assuming we can't use the database, in order to handle this correctly, 
+we need to change the open fd to point at B when A us unlinked.
+
+Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
+Upstream-Status: Pending
+
+Index: git/ports/unix/guts/linkat.c
+===================================================================
+--- git.orig/ports/unix/guts/linkat.c
++++ git/ports/unix/guts/linkat.c
+@@ -116,6 +116,7 @@
+         * if the thing linked is a symlink.
+         */
+        pseudo_client_op(OP_LINK, 0, -1, -1, newpath, &buf);
++       pseudo_client_linked_paths(oldpath, newpath);
+ 
+        errno = save_errno;
+ 
+Index: git/pseudo_client.c
+===================================================================
+--- git.orig/pseudo_client.c
++++ git/pseudo_client.c
+@@ -70,6 +70,8 @@ int pseudo_umask = 022;
+ 
+ static char **fd_paths = NULL;
+ static int nfds = 0;
++static char **linked_fd_paths = NULL;
++static int linked_nfds = 0;
+ static const char **passwd_paths = NULL;
+ static int npasswd_paths = 0;
+ #ifdef PSEUDO_PROFILING
+@@ -889,39 +891,70 @@ fd_path(int fd) {
+ }
+ 
+ static void
+-pseudo_client_path(int fd, const char *path) {
++pseudo_client_path_set(int fd, const char *path, char ***patharray, int *len) {
+        if (fd < 0)
+                return;
+ 
+-       if (fd >= nfds) {
++       if (fd >= *len) {
+                int i;
+                pseudo_debug(PDBGF_CLIENT, "expanding fds from %d to %d\n",
+-                       nfds, fd + 1);
+-               fd_paths = realloc(fd_paths, (fd + 1) * sizeof(char *));
+-               for (i = nfds; i < fd + 1; ++i)
+-                       fd_paths[i] = 0;
+-               nfds = fd + 1;
++                       *len, fd + 1);
++               (*patharray) = realloc((*patharray), (fd + 1) * sizeof(char *));
++               for (i = *len; i < fd + 1; ++i)
++                       (*patharray)[i] = 0;
++               *len = fd + 1;
+        } else {
+-               if (fd_paths[fd]) {
++               if ((*patharray)[fd]) {
+                        pseudo_debug(PDBGF_CLIENT, "reopening fd %d [%s] -- didn't see close\n",
+-                               fd, fd_paths[fd]);
++                               fd, (*patharray)[fd]);
+                }
+                /* yes, it is safe to free null pointers. yay for C89 */
+-               free(fd_paths[fd]);
+-               fd_paths[fd] = 0;
++               free((*patharray)[fd]);
++               (*patharray)[fd] = 0;
+        }
+        if (path) {
+-               fd_paths[fd] = strdup(path);
++               (*patharray)[fd] = strdup(path);
++       }
++}
++
++static void
++pseudo_client_path(int fd, const char *path) {
++       pseudo_client_path_set(fd, path, &fd_paths, &nfds);
++}
++
++void
++pseudo_client_linked_paths(const char *oldpath, const char *newpath) {
++       int fd;
++       for (fd = 3; fd < nfds; ++fd) {
++               if (fd_paths[fd] && !strcmp(oldpath, fd_paths[fd])) {
++                       pseudo_client_path_set(fd, newpath, &linked_fd_paths, &linked_nfds);
++               }
+        }
+ }
+ 
+ static void
++pseudo_client_unlinked_path(const char *path) {
++       int fd;
++       for (fd = 0; fd < linked_nfds; ++fd) {
++               if (linked_fd_paths[fd] && fd_paths[fd] && !strcmp(path, fd_paths[fd])) {
++                       pseudo_client_path(fd, linked_fd_paths[fd]);
++               }
++       }
++}
++
++
++static void
+ pseudo_client_close(int fd) {
+        if (fd < 0 || fd >= nfds)
+                return;
+ 
+        free(fd_paths[fd]);
+        fd_paths[fd] = 0;
++
++       if (fd < linked_nfds) {
++               free(linked_fd_paths[fd]);
++               linked_fd_paths[fd] = 0;
++       }
+ }
+ 
+ /* spawn server */
+@@ -1860,6 +1893,12 @@ pseudo_client_op(pseudo_op_t op, int acc
+                        dirfd);
+                pseudo_client_path(dirfd, fd_path(fd));
+                break;
++       case OP_UNLINK:
++       case OP_DID_UNLINK:
++               if (path)
++                       pseudo_client_unlinked_path(path);
++               do_request = 1;
++               break;
+        /* operations for which we should use the magic uid/gid */
+        case OP_CHMOD:
+        case OP_CREAT:
+@@ -1882,8 +1921,6 @@ pseudo_client_op(pseudo_op_t op, int acc
+        case OP_LINK:
+        case OP_RENAME:
+        case OP_STAT:
+-       case OP_UNLINK:
+-       case OP_DID_UNLINK:
+        case OP_CANCEL_UNLINK:
+        case OP_MAY_UNLINK:
+        case OP_GET_XATTR:
+Index: git/pseudo_client.h
+===================================================================
+--- git.orig/pseudo_client.h
++++ git/pseudo_client.h
+@@ -9,6 +9,7 @@
+ extern pseudo_msg_t *pseudo_client_op(pseudo_op_t op, int access, int fd, int dirfd, const char *path, const PSEUDO_STATBUF *buf, ...);
+ extern int pseudo_client_ignore_path(const char *path);
+ extern int pseudo_client_ignore_fd(int fd);
++extern void pseudo_client_linked_paths(const char *oldpath, const char *newpath);
+ #if PSEUDO_STATBUF_64
+ #define base_lstat real_lstat64
+ #define base_fstat real_fstat64
diff --git a/meta/recipes-devtools/pseudo/pseudo_git.bb b/meta/recipes-devtools/pseudo/pseudo_git.bb
index 56c9b4e232..a5e79ec9a5 100644
--- a/meta/recipes-devtools/pseudo/pseudo_git.bb
+++ b/meta/recipes-devtools/pseudo/pseudo_git.bb
@@ -5,6 +5,7 @@ SRC_URI = "git://git.yoctoproject.org/pseudo;branch=oe-core \
            file://delete_mismatches.patch \
            file://add_ignore_paths.patch \
            file://abort_on_mismatch.patch \
+           file://track_link_fds.patch \
            file://fallback-passwd \
            file://fallback-group \
            "