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jehanne/sys/src/lib/c/9sys/access.c

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libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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/*
libc: rewrite access()
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* This file is part of Jehanne.
*
libposix: add access
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* Copyright (C) 2016-2017 Giacomo Tesio <giacomo@tesio.it>
libc: rewrite access()
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*
* Jehanne is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* Jehanne 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Jehanne. If not, see <http://www.gnu.org/licenses/>.
libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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*/
#include <u.h>
#include <libc.h>
int
libc: introduce "jehanne_" namespace With this commit all functions declared in libc.h have been renamed with the "jehanne_" prefix. This is done for several reason: - it removes conflicts during symbol resolution when linking standard C libraries like newlib or musl - it allows programs depending on a standard C library to directly link to a library depending on our non standard libc (eg libsec). To ease transiction two files are provided: - sys/include/lib9.h that can be included instead of <libc.h> to use the old names (via a simple set of macros) - sys/src/lib/c/lib9.c that can be compiled with a program where the macro provided by lib9.h are too dumb (see for example rc or grep). In the kernel port/lib.h has been modified accordingly and some of the functions it directly provides has been renamed too (eg malloc in qmalloc.c and print in devcons.c).
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jehanne_access(const char *name, int mode)
libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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{
int fd;
libposix: add access
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Dir *db;
kernel&all: create() syscall only sends Tcreate In Plan9 the create syscall fallback on a open(OTRUNC) if the path provided already exists. This is actually a common requirement as most programs (editors, cat...) simply requires that a file is there and is empty, and doesn't care overwriting existing contents (note that this is particularily sensible with something like fossil). In Jehanne the application is responsible of actually handle this "file exists" error but libc provides ocreate() to mimic the Plan9 behaviour. Note that ocreate introduce a subtle race too: the path is walked several times if the file exists, thus it could misbehave on concurrent namespace changes. However I guess this is not going to happen often enough to care now. NOTE we will probably address this rare race too, with a more drammatic change to syscalls: a new walk() syscall that will provide an unopen fd.
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static char omode[] = {
libc: rewrite access()
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OSTAT,
kernel&all: create() syscall only sends Tcreate In Plan9 the create syscall fallback on a open(OTRUNC) if the path provided already exists. This is actually a common requirement as most programs (editors, cat...) simply requires that a file is there and is empty, and doesn't care overwriting existing contents (note that this is particularily sensible with something like fossil). In Jehanne the application is responsible of actually handle this "file exists" error but libc provides ocreate() to mimic the Plan9 behaviour. Note that ocreate introduce a subtle race too: the path is walked several times if the file exists, thus it could misbehave on concurrent namespace changes. However I guess this is not going to happen often enough to care now. NOTE we will probably address this rare race too, with a more drammatic change to syscalls: a new walk() syscall that will provide an unopen fd.
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OEXEC,
OWRITE,
ORDWR,
OREAD,
libc: rewrite access()
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OEXEC, /* 5=4+1 READ|EXEC, EXEC is enough */
kernel&all: create() syscall only sends Tcreate In Plan9 the create syscall fallback on a open(OTRUNC) if the path provided already exists. This is actually a common requirement as most programs (editors, cat...) simply requires that a file is there and is empty, and doesn't care overwriting existing contents (note that this is particularily sensible with something like fossil). In Jehanne the application is responsible of actually handle this "file exists" error but libc provides ocreate() to mimic the Plan9 behaviour. Note that ocreate introduce a subtle race too: the path is walked several times if the file exists, thus it could misbehave on concurrent namespace changes. However I guess this is not going to happen often enough to care now. NOTE we will probably address this rare race too, with a more drammatic change to syscalls: a new walk() syscall that will provide an unopen fd.
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ORDWR,
libc: rewrite access()
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ORDWR /* 7=4+2+1 READ|WRITE|EXEC, ignore EXEC */
kernel&all: create() syscall only sends Tcreate In Plan9 the create syscall fallback on a open(OTRUNC) if the path provided already exists. This is actually a common requirement as most programs (editors, cat...) simply requires that a file is there and is empty, and doesn't care overwriting existing contents (note that this is particularily sensible with something like fossil). In Jehanne the application is responsible of actually handle this "file exists" error but libc provides ocreate() to mimic the Plan9 behaviour. Note that ocreate introduce a subtle race too: the path is walked several times if the file exists, thus it could misbehave on concurrent namespace changes. However I guess this is not going to happen often enough to care now. NOTE we will probably address this rare race too, with a more drammatic change to syscalls: a new walk() syscall that will provide an unopen fd.
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};
libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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libc: rewrite access()
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fd = open(name, omode[mode&AMASK]);
libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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if(fd >= 0){
close(fd);
return 0;
}
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db = jehanne_dirstat(name);
if(db != nil){
fd = db->mode & omode[mode&AMASK];
jehanne_free(db);
if(fd)
return 0;
}
libc: initial import from Harvey Note that libc is what distinguish "native" software from "non-native" in Jehanne: further C libraries can be ported to Jehanne, but this libc will remain the main building block of the system. Also note that a few files have not been ported from Harvey: - 9sys/pushtls.c - port/rijndael.c - port/rijndael.tbl - port/sha2.c Pushtls.c depends on libmp and libsec so libc is not the appropriate place for it. The other three will be moved to libsec.
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return -1;
}