Unnamed repository; edit this file 'description' to name the repository.
Log | Files | Refs | README | LICENSE

commit 0a82586794a2180e89150e11cd3b9f123fa78c31
Author: Anton Kling <>
Date:   Fri, 24 Dec 2021 00:06:06 +0100

first commit

ACOPYING | 661+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
AMakefile | 10++++++++++
AREADME | 42++++++++++++++++++++++++++++++++++++++++++
Ahttp.c | 394+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 1107 insertions(+), 0 deletions(-)

diff --git a/COPYING b/COPYING @@ -0,0 +1,661 @@ + GNU AFFERO GENERAL PUBLIC LICENSE + Version 3, 19 November 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU Affero General Public License is a free, copyleft license for +software and other kinds of works, specifically designed to ensure +cooperation with the community in the case of network server software. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +our General Public Licenses are intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + + Developers that use our General Public Licenses protect your rights +with two steps: (1) assert copyright on the software, and (2) offer +you this License which gives you legal permission to copy, distribute +and/or modify the software. + + A secondary benefit of defending all users' freedom is that +improvements made in alternate versions of the program, if they +receive widespread use, become available for other developers to +incorporate. Many developers of free software are heartened and +encouraged by the resulting cooperation. However, in the case of +software used on network servers, this result may fail to come about. +The GNU General Public License permits making a modified version and +letting the public access it on a server without ever releasing its +source code to the public. + + The GNU Affero General Public License is designed specifically to +ensure that, in such cases, the modified source code becomes available +to the community. It requires the operator of a network server to +provide the source code of the modified version running there to the +users of that server. Therefore, public use of a modified version, on +a publicly accessible server, gives the public access to the source +code of the modified version. + + An older license, called the Affero General Public License and +published by Affero, was designed to accomplish similar goals. This is +a different license, not a version of the Affero GPL, but Affero has +released a new version of the Affero GPL which permits relicensing under +this license. + + The precise terms and conditions for copying, distribution and +modification follow. + + TERMS AND CONDITIONS + + 0. Definitions. + + "This License" refers to version 3 of the GNU Affero General Public License. + + "Copyright" also means copyright-like laws that apply to other kinds of +works, such as semiconductor masks. + + "The Program" refers to any copyrightable work licensed under this +License. Each licensee is addressed as "you". "Licensees" and +"recipients" may be individuals or organizations. + + To "modify" a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of an +exact copy. The resulting work is called a "modified version" of the +earlier work or a work "based on" the earlier work. + + A "covered work" means either the unmodified Program or a work based +on the Program. + + To "propagate" a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + + To "convey" a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user through +a computer network, with no transfer of a copy, is not conveying. + + An interactive user interface displays "Appropriate Legal Notices" +to the extent that it includes a convenient and prominently visible +feature that (1) displays an appropriate copyright notice, and (2) +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + + 1. Source Code. + + The "source code" for a work means the preferred form of the work +for making modifications to it. "Object code" means any non-source +form of a work. + + A "Standard Interface" means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + + The "System Libraries" of an executable work include anything, other +than the work as a whole, that (a) is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and (b) serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +"Major Component", in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + + The "Corresponding Source" for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + + The Corresponding Source need not include anything that users +can regenerate automatically from other parts of the Corresponding +Source. + + The Corresponding Source for a work in source code form is that +same work. + + 2. Basic Permissions. + + All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + + You may make, run and propagate covered works that you do not +convey, without conditions so long as your license otherwise remains +in force. You may convey covered works to others for the sole purpose +of having them make modifications exclusively for you, or provide you +with facilities for running those works, provided that you comply with +the terms of this License in conveying all material for which you do +not control copyright. Those thus making or running the covered works +for you must do so exclusively on your behalf, under your direction +and control, on terms that prohibit them from making any copies of +your copyrighted material outside their relationship with you. + + Conveying under any other circumstances is permitted solely under +the conditions stated below. Sublicensing is not allowed; section 10 +makes it unnecessary. + + 3. Protecting Users' Legal Rights From Anti-Circumvention Law. + + No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + + When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such circumvention +is effected by exercising rights under this License with respect to +the covered work, and you disclaim any intention to limit operation or +modification of the work as a means of enforcing, against the work's +users, your or third parties' legal rights to forbid circumvention of +technological measures. + + 4. Conveying Verbatim Copies. + + You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + + You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + + 5. Conveying Modified Source Versions. + + You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these conditions: + + a) The work must carry prominent notices stating that you modified + it, and giving a relevant date. + + b) The work must carry prominent notices stating that it is + released under this License and any conditions added under section + 7. This requirement modifies the requirement in section 4 to + "keep intact all notices". + + c) You must license the entire work, as a whole, under this + License to anyone who comes into possession of a copy. This + License will therefore apply, along with any applicable section 7 + additional terms, to the whole of the work, and all its parts, + regardless of how they are packaged. This License gives no + permission to license the work in any other way, but it does not + invalidate such permission if you have separately received it. + + d) If the work has interactive user interfaces, each must display + Appropriate Legal Notices; however, if the Program has interactive + interfaces that do not display Appropriate Legal Notices, your + work need not make them do so. + + A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +"aggregate" if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + + 6. Conveying Non-Source Forms. + + You may convey a covered work in object code form under the terms +of sections 4 and 5, provided that you also convey the +machine-readable Corresponding Source under the terms of this License, +in one of these ways: + + a) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by the + Corresponding Source fixed on a durable physical medium + customarily used for software interchange. + + b) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by a + written offer, valid for at least three years and valid for as + long as you offer spare parts or customer support for that product + model, to give anyone who possesses the object code either (1) a + copy of the Corresponding Source for all the software in the + product that is covered by this License, on a durable physical + medium customarily used for software interchange, for a price no + more than your reasonable cost of physically performing this + conveying of source, or (2) access to copy the + Corresponding Source from a network server at no charge. + + c) Convey individual copies of the object code with a copy of the + written offer to provide the Corresponding Source. This + alternative is allowed only occasionally and noncommercially, and + only if you received the object code with such an offer, in accord + with subsection 6b. + + d) Convey the object code by offering access from a designated + place (gratis or for a charge), and offer equivalent access to the + Corresponding Source in the same way through the same place at no + further charge. You need not require recipients to copy the + Corresponding Source along with the object code. If the place to + copy the object code is a network server, the Corresponding Source + may be on a different server (operated by you or a third party) + that supports equivalent copying facilities, provided you maintain + clear directions next to the object code saying where to find the + Corresponding Source. Regardless of what server hosts the + Corresponding Source, you remain obligated to ensure that it is + available for as long as needed to satisfy these requirements. + + e) Convey the object code using peer-to-peer transmission, provided + you inform other peers where the object code and Corresponding + Source of the work are being offered to the general public at no + charge under subsection 6d. + + A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + + A "User Product" is either (1) a "consumer product", which means any +tangible personal property which is normally used for personal, family, +or household purposes, or (2) anything designed or sold for incorporation +into a dwelling. In determining whether a product is a consumer product, +doubtful cases shall be resolved in favor of coverage. For a particular +product received by a particular user, "normally used" refers to a +typical or common use of that class of product, regardless of the status +of the particular user or of the way in which the particular user +actually uses, or expects or is expected to use, the product. A product +is a consumer product regardless of whether the product has substantial +commercial, industrial or non-consumer uses, unless such uses represent +the only significant mode of use of the product. + + "Installation Information" for a User Product means any methods, +procedures, authorization keys, or other information required to install +and execute modified versions of a covered work in that User Product from +a modified version of its Corresponding Source. The information must +suffice to ensure that the continued functioning of the modified object +code is in no case prevented or interfered with solely because +modification has been made. + + If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + + The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or updates +for a work that has been modified or installed by the recipient, or for +the User Product in which it has been modified or installed. Access to a +network may be denied when the modification itself materially and +adversely affects the operation of the network or violates the rules and +protocols for communication across the network. + + Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + + 7. Additional Terms. + + "Additional permissions" are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + + When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + + Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders of +that material) supplement the terms of this License with terms: + + a) Disclaiming warranty or limiting liability differently from the + terms of sections 15 and 16 of this License; or + + b) Requiring preservation of specified reasonable legal notices or + author attributions in that material or in the Appropriate Legal + Notices displayed by works containing it; or + + c) Prohibiting misrepresentation of the origin of that material, or + requiring that modified versions of such material be marked in + reasonable ways as different from the original version; or + + d) Limiting the use for publicity purposes of names of licensors or + authors of the material; or + + e) Declining to grant rights under trademark law for use of some + trade names, trademarks, or service marks; or + + f) Requiring indemnification of licensors and authors of that + material by anyone who conveys the material (or modified versions of + it) with contractual assumptions of liability to the recipient, for + any liability that these contractual assumptions directly impose on + those licensors and authors. + + All other non-permissive additional terms are considered "further +restrictions" within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + + If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + + Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; +the above requirements apply either way. + + 8. Termination. + + You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + + However, if you cease all violation of this License, then your +license from a particular copyright holder is reinstated (a) +provisionally, unless and until the copyright holder explicitly and +finally terminates your license, and (b) permanently, if the copyright +holder fails to notify you of the violation by some reasonable means +prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + + Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + + 9. Acceptance Not Required for Having Copies. + + You are not required to accept this License in order to receive or +run a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + + 10. Automatic Licensing of Downstream Recipients. + + Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + + An "entity transaction" is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + + You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + + 11. Patents. + + A "contributor" is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's "contributor version". + + A contributor's "essential patent claims" are all patent claims +owned or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, "control" includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + + Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + + In the following three paragraphs, a "patent license" is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To "grant" such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + + If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either (1) cause the Corresponding Source to be so +available, or (2) arrange to deprive yourself of the benefit of the +patent license for this particular work, or (3) arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. "Knowingly relying" means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + + If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + + A patent license is "discriminatory" if it does not include within +the scope of its coverage, prohibits the exercise of, or is +conditioned on the non-exercise of one or more of the rights that are +specifically granted under this License. You may not convey a covered +work if you are a party to an arrangement with a third party that is +in the business of distributing software, under which you make payment +to the third party based on the extent of your activity of conveying +the work, and under which the third party grants, to any of the +parties who would receive the covered work from you, a discriminatory +patent license (a) in connection with copies of the covered work +conveyed by you (or copies made from those copies), or (b) primarily +for and in connection with specific products or compilations that +contain the covered work, unless you entered into that arrangement, +or that patent license was granted, prior to 28 March 2007. + + Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + + 12. No Surrender of Others' Freedom. + + If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you may +not convey it at all. For example, if you agree to terms that obligate you +to collect a royalty for further conveying from those to whom you convey +the Program, the only way you could satisfy both those terms and this +License would be to refrain entirely from conveying the Program. + + 13. Remote Network Interaction; Use with the GNU General Public License. + + Notwithstanding any other provision of this License, if you modify the +Program, your modified version must prominently offer all users +interacting with it remotely through a computer network (if your version +supports such interaction) an opportunity to receive the Corresponding +Source of your version by providing access to the Corresponding Source +from a network server at no charge, through some standard or customary +means of facilitating copying of software. This Corresponding Source +shall include the Corresponding Source for any work covered by version 3 +of the GNU General Public License that is incorporated pursuant to the +following paragraph. + + Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the work with which it is combined will remain governed by version +3 of the GNU General Public License. + + 14. Revised Versions of this License. + + The Free Software Foundation may publish revised and/or new versions of +the GNU Affero General Public License from time to time. Such new versions +will be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + + Each version is given a distinguishing version number. If the +Program specifies that a certain numbered version of the GNU Affero General +Public License "or any later version" applies to it, you have the +option of following the terms and conditions either of that numbered +version or of any later version published by the Free Software +Foundation. If the Program does not specify a version number of the +GNU Affero General Public License, you may choose any version ever published +by the Free Software Foundation. + + If the Program specifies that a proxy can decide which future +versions of the GNU Affero General Public License can be used, that proxy's +public statement of acceptance of a version permanently authorizes you +to choose that version for the Program. + + Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + + 15. Disclaimer of Warranty. + + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF +ALL NECESSARY SERVICING, REPAIR OR CORRECTION. + + 16. Limitation of Liability. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGES. + + 17. Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + <one line to give the program's name and a brief idea of what it does.> + Copyright (C) <year> <name of author> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with this program. If not, see <>. + +Also add information on how to contact you by electronic and paper mail. + + If your software can interact with users remotely through a computer +network, you should also make sure that it provides a way for users to +get its source. For example, if your program is a web application, its +interface could display a "Source" link that leads users to an archive +of the code. There are many ways you could offer source, and different +solutions will be better for different programs; see section 13 for the +specific requirements. + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU AGPL, see +<>. diff --git a/Makefile b/Makefile @@ -0,0 +1,10 @@ +CFLAGS=-Wall -pedantic -Werror -Wimplicit-fallthrough +CC=musl-clang + +http: http.c + $(CC) $(CFLAGS) $^ -o $@ + sudo chown root:root $@ + sudo chmod u+s $@ + +clean: + rm http diff --git a/README b/README @@ -0,0 +1,42 @@ +smol-http +========= +A simple http server supporting GET requests. + +Usage +----- + +Clone this respository and compile the software. + + git clone + cd smol_http + make + +The appplications default values can be configured via changing the values in +the http.c file and recompilling the application. + +It is also possible to change values using the command line arguments + + -p port + + -d root directory + +Security +-------- + +The application is a seteuid binary and shall not be ran as root but instead +should be ran as a low privlege user that the application will later drop +privleges to. + +License +------- + +This program is licensed under Affero GNU Public License Version 3. This may +require you to in ceratin circumstances provide the source code of the +application. Make sure you are following the license. See COPYING for more +information. + +One conceivable way of complying with the AGPL should no changes be made would +be to simply link to this git repo and the commit the code is on. If changes +are made then providing a diff file along with the git repo link should be good +enough. Though this is paragraph does not trump anything stated in COPYING nor +add any additional legal restrictions towards you using the software. diff --git a/http.c b/http.c @@ -0,0 +1,394 @@ +/* +Copyright © 2021 Anton Kling <> + +This program is free software: you can redistribute it and/or modify +it under the terms of the GNU Affero General Public License as +published by the Free Software Foundation, either version 3 of the +License, or (at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU Affero General Public License for more details. + +You should have received a copy of the GNU Affero General Public License +along with this program. If not, see <>. +*/ +#include <arpa/inet.h> +#include <assert.h> +#include <dirent.h> +#include <errno.h> +#include <fcntl.h> +#include <getopt.h> +#include <netdb.h> +#include <pwd.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <unistd.h> + +// Should xxx.html not exist these will be supplied instead. +#define DEFAULT_404_SITE "404 - Not Found\0" +#define DEFAULT_400_SITE "400 - Bad Request\0" + +// Default port should -p not be supplied. +#define DEFAULT_PORT 1337 + +// Default directory should -d not be supplied. +#define WEBSITE_ROOT "./site/" + +#define MAX_BUFFER 4096 // Size of the read buffer + +#ifndef PATH_MAX +#define _PATH_MAX 4096 +#else +#define _PATH_MAX PATH_MAX +#endif + +#define COND_PERROR_EXP(condition, function_name, expression)\ + if(condition){perror(function_name);expression;} + +#define HAS_PLEDGE (__OpenBSD__ | __SerenityOS__) +#define HAS_UNVEIL (__OpenBSD__ | __SerenityOS__) + +#if HAS_PLEDGE +#define PLEDGE(promise, exec) COND_PERROR_EXP(-1 == pledge(promise, exec), "pledge", exit(1)) +#else +#define PLEDGE(promise, exec) ; +#endif + +#if HAS_ENVEIL +#define UNVEIL(path, permissions) COND_PERROR_EXP(-1 == unveil(path, permissions), "unveil", exit(1)) +#else +#define UNVEIL(path, permissions) ; +#endif + +#define ASSERT_NOT_REACHED assert(0) + +#define COPYRIGHT_STATEMENT "\ +This program is licensed under Affero GNU Public License Version 3.\n\ +See for more information.\n\ +THIS PROGRAM COMES WITHOUT ANY WARRANTY; without even the implied\n\ +warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE." + +static const struct +{ + char *ext; + char *type; +} mimes[] = { + { "xml", "application/xml; charset=utf-8" }, + { "xhtml", "application/xhtml+xml; charset=utf-8" }, + { "html", "text/html; charset=utf-8" }, + { "htm", "text/html; charset=utf-8" }, + { "css", "text/css; charset=utf-8" }, + { "txt", "text/plain; charset=utf-8" }, + { "md", "text/plain; charset=utf-8" }, + { "c", "text/plain; charset=utf-8" }, + { "h", "text/plain; charset=utf-8" }, + { "gz", "application/x-gtar" }, + { "tar", "application/tar" }, + { "pdf", "application/x-pdf" }, + { "png", "image/png" }, + { "gif", "image/gif" }, + { "jpeg", "image/jpg" }, + { "jpg", "image/jpg" }, + { "iso", "application/x-iso9660-image" }, + { "webp", "image/webp" }, + { "svg", "image/svg+xml; charset=utf-8" }, + { "flac", "audio/flac" }, + { "mp3", "audio/mpeg" }, + { "ogg", "audio/ogg" }, + { "mp4", "video/mp4" }, + { "ogv", "video/ogg" }, + { "webm", "video/webm" }, +}; + +int chroot(const char *path); + +const char * const get_mime(const char * file) +{ + for(;*file && *file++ != '.';); + for(size_t i = 0;i < sizeof(mimes)/sizeof(mimes[0])-1;i++) + if(0 == strcmp(mimes[i].ext, file)) + return mimes[i].type; + + return "application/octet-stream"; +} + +const char * const get_status_code(uint16_t code) +{ + switch(code) + { +case 400: + return "400 Bad Request"; +case 404: + return "404 File Not Found"; +case 200: default: + return "200 OK"; + } +} + +void connection_handler(int socket_desc) +{ + PLEDGE("stdio rpath", ""); + char recv_buffer[MAX_BUFFER]; + int status_code = 200; + + // We can ignore SIGPIPE as we already have checks + // that would deal with this. + COND_PERROR_EXP(SIG_ERR == signal(SIGPIPE, SIG_IGN), "signal", goto cleanup); + + ssize_t recv_size; + COND_PERROR_EXP(-1 == (recv_size = recv(socket_desc, + recv_buffer, MAX_BUFFER-1, 0)), "recv", goto cleanup); + // Null terminate the request. + recv_buffer[recv_size] = 0; + + char * filename = recv_buffer; + // Get to the second argument in the buffer. + for(;*filename && *filename++ != ' ';); + + // If we had only one argument then just provide 400.html. + if(!(*filename)) + { + filename = "/400.html"; + status_code = 400; + goto skip_filename_parse; + } + + int enter_directory = 0; + uint16_t i; + for(i = 0;filename[i] && + filename[i] != ' ' && + filename[i] != '\n' && + filename[i] != '\r';i++); + + filename[i] = 0; + + struct stat statbuf; + if(-1 == stat(filename, &statbuf)) + { + if(ENOENT == errno) + goto not_found; + goto cleanup; + } + if(S_ISDIR(statbuf.st_mode)) + { + enter_directory = 1; + chdir(filename); + filename = "index.html"; + } + + int fd; + char * const_site_content; +skip_filename_parse: +redo: + const_site_content = NULL; + if(-1 == (fd = open(filename, O_RDONLY))) + { + if(1 == enter_directory) + { + enter_directory = 2; + goto write; + } + + if(400 == status_code) + { + const_site_content = DEFAULT_400_SITE; + goto write; + } + + if(0 == strcmp(filename, "/404.html") && 404 == status_code) + { + const_site_content = DEFAULT_404_SITE; + goto write; + } + +not_found: + filename = "/404.html"; + status_code = 404; + goto redo; + } + +write: + if(0 > dprintf(socket_desc, "HTTP/1.0 %s\r\nContent-Type: %s\r\nServer: smol_http\r\n\r\n", get_status_code(status_code), get_mime(filename))) + { + puts("dprintf error"); + goto cleanup; + } + + if(const_site_content) + { + PLEDGE("stdio", NULL); + COND_PERROR_EXP(-1 == write(socket_desc, const_site_content, strlen(const_site_content)), "write", /*NOP*/); + goto cleanup; + } + + // Should ./index.html be unable to be read we create a + // directory listing. + if(2 == enter_directory) + { + // Get the directory contents and provide that to the client. + DIR *d; + COND_PERROR_EXP(NULL == (d = opendir(".")), "opendir", goto cleanup); + + char current_path[_PATH_MAX]; + char back_path[_PATH_MAX]; + COND_PERROR_EXP(!realpath(".", current_path), "realpath", goto directory_cleanup) + COND_PERROR_EXP(!realpath("..", back_path), "realpath", goto directory_cleanup) + if(0 > dprintf(socket_desc, "Index of %s/<br><a href='%s'>./</a><br><a href='%s'>../</a><br>", + current_path, current_path, back_path)) + { + puts("dprintf error"); + goto directory_cleanup; + } + for(struct dirent * dir;(dir = readdir(d));) + { + if(0 == strcmp(dir->d_name, ".") || 0 == strcmp(dir->d_name, "..")) + continue; + + char tmp_path[_PATH_MAX]; + COND_PERROR_EXP(!realpath(dir->d_name, tmp_path), "realpath", break); + if(0 > dprintf(socket_desc, "<a href='%s'>%s%s</a><br>", tmp_path, dir->d_name, (DT_DIR == dir->d_type)?"/":"")) + { + puts("dprintf error"); + break; + } + } +directory_cleanup: + closedir(d); + goto cleanup; + } + PLEDGE("stdio", NULL); + + char rwbuf[4096]; + for(int l;0 != (l = read(fd, rwbuf, sizeof(rwbuf)));) + { + COND_PERROR_EXP(-1 == l, "read", break); + COND_PERROR_EXP(-1 == write(socket_desc, rwbuf, l), "write", break); + } + + close(fd); +cleanup: + PLEDGE("", NULL); + close(socket_desc); +} + +int drop_root_privleges(void) +{ + COND_PERROR_EXP(0 != seteuid(getuid()), "seteuid", return 0); + COND_PERROR_EXP(0 != setegid(getgid()), "setegid", return 0); + if(0 == geteuid()) + { + fprintf(stderr, + "Error: Program can not be ran by a root user.\n"); + return 0; + } + return 1; +} + +int init_server(short port, const char * website_root) +{ + int socket_desc, new_socket; + struct sockaddr_in server; + struct sockaddr client; + socklen_t c; + + UNVEIL(website_root, "r"); + UNVEIL(NULL, NULL); // Disable usage of unveil()(this will also be + // done by our pledge() call) + // Enter a chroot jail ASAP. + COND_PERROR_EXP(0 != chroot(website_root), "chroot", return 1); + PLEDGE("stdio inet rpath exec id proc", ""); + + // I am unsure if chdir("/") even can fail. + // But I will keep this check here just in case. + COND_PERROR_EXP(0 != chdir("/"), "chdir", return 1); + + COND_PERROR_EXP(-1 == (socket_desc = + socket(AF_INET, SOCK_STREAM, 0)), "socket", return 1); + + server.sin_family = AF_INET; + server.sin_addr.s_addr = INADDR_ANY; + server.sin_port = htons(port); + + COND_PERROR_EXP(0 > bind(socket_desc,(struct sockaddr*)&server, + sizeof(server)), "bind", return 1); + + // Everything that requires root privleges is done, + // we can now drop privleges. + if(!drop_root_privleges()) + { + fprintf(stderr, + "Unable to drop privleges.\n"); + return 1; + } + + PLEDGE("stdio inet rpath exec proc", NULL); + + COND_PERROR_EXP(0 != listen(socket_desc, 3), "listen", return 1); + + c = sizeof(struct sockaddr_in); + for(;(new_socket = accept(socket_desc, &client, &c));) + { + COND_PERROR_EXP(-1 == new_socket, "accept", continue); + + // Create a child and handle the connection + pid_t pid; + COND_PERROR_EXP(-1 == (pid = fork()), "fork", continue); + if(0 != pid) // We are the parent. + { + close(new_socket); + continue; + } + // We are the child. + connection_handler(new_socket); + close(socket_desc); + _exit(0); + } + close(socket_desc); + return 0; +} + +void usage(const char * const str) +{ + fprintf(stderr, + "Usage: %s [-p PORT] -h(Print this message)\n", str); + puts("---"); + puts(COPYRIGHT_STATEMENT); +} + +int main(int argc, char ** argv) +{ + if(0 != geteuid()) + { + fprintf(stderr, + "Error: Program does not have root privleges."); + return 1; + } + + short port = DEFAULT_PORT; + char * website_root = WEBSITE_ROOT; + for(int ch;-1 != (ch = getopt(argc, argv, "p:d:h"));) + switch((char)ch) + { + case 'p': + if(0 == (port = atoi(optarg))) + { + usage(argv[0]); + return 0; + } + break; + case 'd': + website_root = optarg; + break; + case '?': case ':': case 'h': + usage(argv[0]); + return 0; + } + + return init_server(port, website_root); +}