podman-remote: Cannot build if context directory is symlink

[tnk4on]

Description

When building with podman-remote, an error occurs if the context directory is symlink.

Steps to reproduce the issue:

If the context directory is symlink.

# tree
.
├── test
│   └── Containerfile
└── test2 -> test/

2 directories, 1 file

# cd test2; pwd
/root/build-test/test2
# podman -r build -t test2 .
Error: stat /var/tmp/libpod_builder630693276/build/root/build-test/test2/Containerfile: no such file or directory

If the context directory is a real directory.

# cd ../test; pwd
/root/build-test/test
# podman -r build -t test .
STEP 1/2: FROM registry.access.redhat.com/ubi8/ubi
STEP 2/2: RUN uname -a
Linux b20a3e8238f9 5.14.18-300.fc35.x86_64 containers/buildah#1 SMP Fri Nov 12 16:43:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
COMMIT test
--> 88f8a6e2a4a
Successfully tagged localhost/test:latest
88f8a6e2a4ad0b6f24db25431dffb828a8c1c5fa81ac5aa760e1ce4d3e58b176

Additional notes:
I reproduced the same error on macOS remote client(v3.4.2 and latest main branch).
This error will block the execution of "Clone Repository in Container Volume" in VS Code on macOS. It works fine when using Docker.

Output of podman version if reporting a podman build issue:

# podman -r version
Client:
Version:      4.0.0-dev
API Version:  4.0.0-dev
Go Version:   go1.16.8
Git Commit:   93138541f3119b81c170e5ce904a8c4e6cece842
Built:        Thu Nov 25 03:56:42 2021
OS/Arch:      linux/amd64

Server:
Version:      4.0.0-dev
API Version:  4.0.0-dev
Go Version:   go1.16.8
Git Commit:   93138541f3119b81c170e5ce904a8c4e6cece842
Built:        Thu Nov 25 03:56:42 2021
OS/Arch:      linux/amd64

Output of cat /etc/*release:

# cat /etc/*release
Fedora release 35 (Thirty Five)
NAME="Fedora Linux"
VERSION="35 (Server Edition)"
ID=fedora
VERSION_ID=35
VERSION_CODENAME=""
PLATFORM_ID="platform:f35"
PRETTY_NAME="Fedora Linux 35 (Server Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:35"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f35/system-administrators-guide/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=35
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=35
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Server Edition"
VARIANT_ID=server
Fedora release 35 (Thirty Five)
Fedora release 35 (Thirty Five)

Output of uname -a:

# uname -a
Linux fedora-1 5.14.18-300.fc35.x86_64 containers/buildah#1 SMP Fri Nov 12 16:43:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf:

# cat /etc/containers/storage.conf
# This file is is the configuration file for all tools
# that use the containers/storage library.
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver, Must be set for proper operation.
driver = "overlay"

# Temporary storage location
runroot = "/run/containers/storage"

# Primary Read/Write location of container storage
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
]

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partitioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = "false"

# Inodes is used to set a maximum inodes of the container image.
# inodes = ""

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
#mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev,metacopy=on"

# Set to skip a PRIVATE bind mount on the storage home directory.
# skip_mount_home = "false"

# Size is used to set a maximum size of the container image.
# size = ""

# ForceMask specifies the permissions mask that is used for new files and
# directories.
#
# The values "shared" and "private" are accepted.
# Octal permission masks are also accepted.
#
#  "": No value specified.
#     All files/directories, get set with the permissions identified within the
#     image.
#  "private": it is equivalent to 0700.
#     All files/directories get set with 0700 permissions.  The owner has rwx
#     access to the files. No other users on the system can access the files.
#     This setting could be used with networked based homedirs.
#  "shared": it is equivalent to 0755.
#     The owner has rwx access to the files and everyone else can read, access
#     and execute them. This setting is useful for sharing containers storage
#     with other users.  For instance have a storage owned by root but shared
#     to rootless users as an additional store.
#     NOTE:  All files within the image are made readable and executable by any
#     user on the system. Even /etc/shadow within your image is now readable by
#     any user.
#
#   OCTAL: Users can experiment with other OCTAL Permissions.
#
#  Note: The force_mask Flag is an experimental feature, it could change in the
#  future.  When "force_mask" is set the original permission mask is stored in
#  the "user.containers.override_stat" xattr and the "mount_program" option must
#  be specified. Mount programs like "/usr/bin/fuse-overlayfs" present the
#  extended attribute permissions to processes within containers rather then the
#  "force_mask"  permissions.
#
# force_mask = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# metadata_size is used to set the `pvcreate --metadatasize` options when
# creating thin devices. Default is 128k
# metadata_size = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0"

[flouthoc]

@tnk4on I don't think this a buildah issue it seems to be failing at very early level hence moving it to podman. I don't have a remote setup but sharing --log-level=debug could be helpful.

[Luap99]

I think this already fixed in the main branch, see #11732

[tnk4on]

@flouthoc Thank you for moving the issue!
The debug log is below.

# podman --log-level debug -r build -t test2 .
INFO[0000] podman filtering at log level debug
DEBU[0000] Called build.PersistentPreRunE(podman --log-level debug -r build -t test2 .)
DEBU[0000] SSH Ident Key "/root/.ssh/id_ecdsa" SHA256:7DMAeeupk5yNBFP/DOVVtKFKn21/uJwLBTZht9JjWz4 ecdsa-sha2-nistp256
DEBU[0000] DoRequest Method: GET URI: http://d/v4.0.0/libpod/_ping
DEBU[0000] SSH Ident Key "/root/.ssh/id_ecdsa" SHA256:7DMAeeupk5yNBFP/DOVVtKFKn21/uJwLBTZht9JjWz4 ecdsa-sha2-nistp256
DEBU[0000] DoRequest Method: GET URI: http://d/v4.0.0/libpod/_ping
DEBU[0000] Loading registries configuration "/etc/containers/registries.conf"
DEBU[0000] Loading registries configuration "/etc/containers/registries.conf.d/000-shortnames.conf"
DEBU[0000] DoRequest Method: POST URI: http://d/v4.0.0/libpod/build
Error: stat /var/tmp/libpod_builder150168969/build/root/build-test/test2/Containerfile: no such file or directory

[tnk4on]

@Luap99 Thanks for the information on the related issue.
As far as I've tried on my macOS, this issue doesn't seem to be fixed...

[Luap99]

The path is slightly different between your error and the old one:
/var/tmp/libpod_builder150168969/build/root/build-test/test2/Containerfile while the old one was /var/tmp/libpod_builder324688225/build/Dockerfile. I guess the problem is the extra root/build-test/test2 in the path.

[tnk4on]

Sorry for the confusion.
The debug log was re-fetched from the newly created Podman environment. It is reproducible.

[Luap99]

No I am saying your path is different from the one in the old issue #11732, you have a extra root/build-test/test2 in there

Can you try with the full path to the directory, e.g. podman -r build -t test2 /path/to/link

[tnk4on]

OK, I understand. I was able to build it by specifying the path.

# podman -r build -t test2 /root/build-test/test2
STEP 1/2: FROM registry.access.redhat.com/ubi8/ubi
STEP 2/2: RUN uname -a
Linux b20a3e8238f9 5.14.18-300.fc35.x86_64 #1 SMP Fri Nov 12 16:43:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
COMMIT test2
--> a27bd92387e
Successfully tagged localhost/test2:latest
a27bd92387e278cbf840d9c7c3e4af69eda5cca00573c9d1e49441d50e12d83c

The Linux version of podman-remote seems to be fine.
Only if the server side has files in the same path as the client side.

[tnk4on]

On macOS, the error continues.

$ sw_vers
ProductName:	macOS
ProductVersion:	11.6.1
BuildVersion:	20G224

$ ls -l /tmp
lrwxr-xr-x@ 1 root  wheel  11  1  1  2020 /tmp -> private/tmp
$ tree /tmp/test
/tmp/test
└── Containerfile

0 directories, 1 file

$ podman version
Client:
Version:      4.0.0-dev
API Version:  4.0.0-dev
Go Version:   go1.17.2
Git Commit:   ed83ef2517ba4d6a0c7659206fe3a2faa0bdf547
Built:        Tue Nov 23 04:29:35 2021
OS/Arch:      darwin/amd64

Server:
Version:      4.0.0-dev
API Version:  4.0.0-dev
Go Version:   go1.16.8
Git Commit:   7324d94648a9987b0de2dc95cf1b6fbc20592532
Built:        Fri Nov 26 02:13:03 2021
OS/Arch:      linux/amd64

$ podman build -t from-mac /tmp/test/
Error: stat /var/tmp/libpod_builder009900604/build/tmp/test/Containerfile: no such file or directory

$ podman build -t from-mac /private/tmp/test/
STEP 1/2: FROM registry.access.redhat.com/ubi8/ubi
STEP 2/2: RUN uname -a
Linux b20a3e8238f9 5.14.18-300.fc35.x86_64 #1 SMP Fri Nov 12 16:43:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
COMMIT from-mac
--> 5b99ea27313
Successfully tagged localhost/from-mac:latest
5b99ea27313b9ab2f8af67e89e5a4cb482114dcced6df6b15c33b463ecf63e7c

[tnk4on]

The following code solved the problem. This works not only for macOS, but also for podman-remote on Linux

$ git diff pkg/bindings/images/build.go
diff --git a/pkg/bindings/images/build.go b/pkg/bindings/images/build.go
index 3b0bebe9f..6e636aa7c 100644
--- a/pkg/bindings/images/build.go
+++ b/pkg/bindings/images/build.go
@@ -345,6 +345,13 @@ func Build(ctx context.Context, containerFiles []string, options entities.BuildO
                        }
                        c = tmpFile.Name()
                }
+
+               cfDir := filepath.Dir(c)
+               if absDir, err := filepath.EvalSymlinks(cfDir); err == nil {
+                       name := filepath.ToSlash(strings.TrimPrefix(c, cfDir+string(filepath.Separator)))
+                       c = filepath.Join(absDir,name)
+               }
+
                containerfile, err := filepath.Abs(c)
                if err != nil {
                        logrus.Errorf("Cannot find absolute path of %v: %v", c, err)