[PATCH 0/9] Add library mode to source builtin

[Matheus Afonso Martins Moreira]

Bash scripts can be tricky to get right so reusing proven solutions
as shell script libraries is of immense value. However, the existing
shell script sourcing mechanisms are suboptimal for this task.

The source builtin uses the PATH variable for resolving file names
which means they would have to be placed alongside normal executables
which could cause false positives: executables and commands might be
accidentally sourced instead, causing hard to debug problems.

This could be fixed by overriding PATH so that it contains
only library directories but this interferes with the normal
execution of the sourced scripts: they are no longer able to
run commands normally because the commands are not in the PATH.
This is an undesirable and ultimately unnecessary limitation.

This patch set adds a special operating mode to the existing source
builtin to make it behave in the desired way. When source is passed
the options --library or -l, it will search for files in the
directories given by the BASH_LIBRARIES_PATH environment variable,
and only in those directories. The PATH will not be modified.

A build time configurable default value is defined which includes
the user's home directory in addition to system directories,
enabling users to easily develop their own scripting systems.
This forms the basis of a rudimentary module loading system.

In order to support this feature, existing code was refactored
so as to be more functional and parameterized. Bash's existing
facilities were reused as much as possible.

Signed-off-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>

Matheus Afonso Martins Moreira (9):
  builtins: extract file content executor function
  findcmd: parameterize path variable in functions
  findcmd: define the user library finder function
  bashgetopt: define long option shortener function
  builtins/source: refactor file searching function
  builtins/source: define library search function
  builtins/source: add the -l|--library options
  builtins/source: search libraries in library mode
  variables: define default BASH_LIBRARIES_PATH

 builtins/bashgetopt.c |  24 +++++++
 builtins/bashgetopt.h |   7 ++
 builtins/common.c     |  64 ++++++++++++++++++
 builtins/common.h     |   1 +
 builtins/source.def   | 153 ++++++++++++++++++++----------------------
 config-top.h          |   7 ++
 findcmd.c             |  37 ++++++----
 findcmd.h             |   1 +
 variables.c           |   1 +
 9 files changed, 203 insertions(+), 92 deletions(-)

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2.44.0