cap_fileargs: add fileargs_lstat service
Add fileargs_lstat function to cap_fileargs casper service to be able to lstat files while in capability mode. It can only lstat files given in fileargs_init. Submitted by: Bora Özarslan <borako.ozarslan@gmail.com> Reviewed by: oshogbo, cem (partial) MFC after: 3 weeks Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D19548
This commit is contained in:
Ed Maste
parent
fc07a84f80
commit
7b558caee3
@ -24,7 +24,7 @@
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 12, 2018
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.Dd April 17, 2019
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.Dt CAP_FILEARGS 3
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.Os
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.Sh NAME
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@ -33,6 +33,7 @@
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.Nm fileargs_init ,
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.Nm fileargs_initnv ,
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.Nm fileargs_free ,
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.Nm fileargs_lstat ,
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.Nm fileargs_open ,
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.Nm fileargs_fopen
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.Nd "library for handling files in capability mode"
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@ -43,9 +44,9 @@
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.In libcasper.h
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.In casper/cap_fileargs.h
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.Ft "fileargs_t *"
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.Fn fileargs_init "int argc" "char *argv[]" "int flags" "mode_t mode" "cap_rights_t *rightsp"
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.Fn fileargs_init "int argc" "char *argv[]" "int flags" "mode_t mode" "cap_rights_t *rightsp" "int operations"
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.Ft "fileargs_t *"
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.Fn fileargs_cinit "cap_channel_t *cas" "int argc" "char *argv[]" "int flags" "mode_t mode" "cap_rights_t *rightsp"
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.Fn fileargs_cinit "cap_channel_t *cas" "int argc" "char *argv[]" "int flags" "mode_t mode" "cap_rights_t *rightsp" "int operations"
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.Ft "fileargs_t *"
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.Fn fileargs_cinitnv "cap_channel_t *cas" "nvlist_t *limits"
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.Ft "fileargs_t *"
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@ -53,6 +54,8 @@
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.Ft "void"
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.Fn fileargs_free "fileargs_t *fa"
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.Ft "int"
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.Fn fileargs_lstat "fileargs_t *fa" "const char *path" "struct stat *sb"
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.Ft "int"
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.Fn fileargs_open "fileargs_t *fa" "const char *name"
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.Ft "FILE *"
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.Fn fileargs_fopen "fileargs_t *fa" "const char *name" "const char *mode"
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@ -97,6 +100,22 @@ The
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argument contains a list of the capability rights which file should be limited to.
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For more details of the capability rights see
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.Xr cap_rights_init 3 .
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The
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.Fa operations
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argument limits the operations that are available using
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.Nm system.fileargs .
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.Fa operations
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is a combination of:
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.Bl -ohang -offset indent
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.It FA_OPEN
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Allow
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.Fn fileargs_open
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and
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.Fn fileargs_fopen .
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.It FA_LSTAT
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Allow
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.Fn fileargs_lstat .
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.El
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.Pp
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The function
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.Fn fileargs_cinit
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@ -126,6 +145,11 @@ The function handle
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.Dv NULL
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argument.
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.Pp
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The function
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.Fn fileargs_lstat
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is equivalent to
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.Xr lstat 2 .
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.Pp
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The functions
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.Fn fileargs_open
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and
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@ -165,6 +189,15 @@ must contain the
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The
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.Va mode
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argument tells which what mode file should be created.
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.It operations (NV_TYPE_NUMBER)
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The
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.Va operations
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limits the usable operations for
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.Fa system.fileargs .
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The possible values are explained as
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.Va operations
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argument with
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.Fn fileargs_init .
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.El
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.Pp
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The
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@ -201,7 +234,7 @@ argv += optind;
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/* Create capability to the system.fileargs service. */
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fa = fileargs_init(argc, argv, O_RDONLY, 0,
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cap_rights_init(&rights, CAP_READ));
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cap_rights_init(&rights, CAP_READ), FA_OPEN);
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if (fa == NULL)
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err(1, "unable to open system.fileargs service");
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@ -222,6 +255,7 @@ fileargs_free(fa);
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.Ed
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.Sh SEE ALSO
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.Xr cap_enter 2 ,
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.Xr lstat 2 ,
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.Xr open 2 ,
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.Xr cap_rights_init 3 ,
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.Xr err 3 ,
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@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/cnv.h>
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#include <sys/dnv.h>
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#include <sys/nv.h>
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#include <sys/stat.h>
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#include <assert.h>
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#include <errno.h>
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@ -59,7 +60,36 @@ struct fileargs {
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};
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static int
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fileargs_get_cache(fileargs_t *fa, const char *name)
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fileargs_get_lstat_cache(fileargs_t *fa, const char *name, struct stat *sb)
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{
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const nvlist_t *nvl;
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size_t size;
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const void *buf;
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assert(fa != NULL);
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assert(fa->fa_magic == FILEARGS_MAGIC);
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assert(name != NULL);
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if (fa->fa_cache == NULL)
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return (-1);
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nvl = dnvlist_get_nvlist(fa->fa_cache, name, NULL);
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if (nvl == NULL)
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return (-1);
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if (!nvlist_exists_binary(nvl, "stat")) {
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return (-1);
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}
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buf = nvlist_get_binary(nvl, "stat", &size);
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assert(size == sizeof(*sb));
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memcpy(sb, buf, size);
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return (0);
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}
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static int
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fileargs_get_fd_cache(fileargs_t *fa, const char *name)
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{
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int fd;
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const nvlist_t *nvl;
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@ -80,6 +110,12 @@ fileargs_get_cache(fileargs_t *fa, const char *name)
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return (-1);
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tnvl = nvlist_take_nvlist(fa->fa_cache, name);
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if (!nvlist_exists_descriptor(tnvl, "fd")) {
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nvlist_destroy(tnvl);
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return (-1);
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}
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fd = nvlist_take_descriptor(tnvl, "fd");
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nvlist_destroy(tnvl);
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@ -102,7 +138,7 @@ fileargs_set_cache(fileargs_t *fa, nvlist_t *nvl)
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}
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static nvlist_t*
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fileargs_fetch(fileargs_t *fa, const char *name)
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fileargs_fetch(fileargs_t *fa, const char *name, const char *cmd)
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{
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nvlist_t *nvl;
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int serrno;
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@ -111,7 +147,7 @@ fileargs_fetch(fileargs_t *fa, const char *name)
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assert(name != NULL);
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nvl = nvlist_create(NV_FLAG_NO_UNIQUE);
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nvlist_add_string(nvl, "cmd", "open");
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nvlist_add_string(nvl, "cmd", cmd);
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nvlist_add_string(nvl, "name", name);
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nvl = cap_xfer_nvlist(fa->fa_chann, nvl);
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@ -130,7 +166,7 @@ fileargs_fetch(fileargs_t *fa, const char *name)
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static nvlist_t *
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fileargs_create_limit(int argc, const char * const *argv, int flags,
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mode_t mode, cap_rights_t *rightsp)
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mode_t mode, cap_rights_t *rightsp, int operations)
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{
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nvlist_t *limits;
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int i;
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@ -140,6 +176,7 @@ fileargs_create_limit(int argc, const char * const *argv, int flags,
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return (NULL);
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nvlist_add_number(limits, "flags", flags);
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nvlist_add_number(limits, "operations", operations);
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if (rightsp != NULL) {
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nvlist_add_binary(limits, "cap_rights", rightsp,
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sizeof(*rightsp));
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@ -172,7 +209,7 @@ fileargs_create(cap_channel_t *chan, int fdflags)
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fileargs_t *
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fileargs_init(int argc, char *argv[], int flags, mode_t mode,
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cap_rights_t *rightsp)
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cap_rights_t *rightsp, int operations)
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{
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nvlist_t *limits;
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@ -181,7 +218,7 @@ fileargs_init(int argc, char *argv[], int flags, mode_t mode,
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}
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limits = fileargs_create_limit(argc, (const char * const *)argv, flags,
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mode, rightsp);
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mode, rightsp, operations);
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if (limits == NULL)
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return (NULL);
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@ -190,7 +227,7 @@ fileargs_init(int argc, char *argv[], int flags, mode_t mode,
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fileargs_t *
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fileargs_cinit(cap_channel_t *cas, int argc, char *argv[], int flags,
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mode_t mode, cap_rights_t *rightsp)
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mode_t mode, cap_rights_t *rightsp, int operations)
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{
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nvlist_t *limits;
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@ -199,7 +236,7 @@ fileargs_cinit(cap_channel_t *cas, int argc, char *argv[], int flags,
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}
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limits = fileargs_create_limit(argc, (const char * const *)argv, flags,
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mode, rightsp);
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mode, rightsp, operations);
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if (limits == NULL)
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return (NULL);
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@ -234,7 +271,7 @@ fileargs_cinitnv(cap_channel_t *cas, nvlist_t *limits)
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cap_channel_t *chann;
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fileargs_t *fa;
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int serrno, ret;
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int flags;
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int flags, operations;
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assert(cas != NULL);
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@ -252,6 +289,7 @@ fileargs_cinitnv(cap_channel_t *cas, nvlist_t *limits)
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}
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flags = nvlist_get_number(limits, "flags");
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operations = nvlist_get_number(limits, "operations");
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/* Limits are consumed no need to free them. */
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ret = cap_limit_set(chann, limits);
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@ -291,11 +329,11 @@ fileargs_open(fileargs_t *fa, const char *name)
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return (-1);
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}
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fd = fileargs_get_cache(fa, name);
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fd = fileargs_get_fd_cache(fa, name);
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if (fd != -1)
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return (fd);
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nvl = fileargs_fetch(fa, name);
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nvl = fileargs_fetch(fa, name, "open");
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if (nvl == NULL)
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return (-1);
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@ -322,6 +360,53 @@ fileargs_fopen(fileargs_t *fa, const char *name, const char *mode)
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return (fdopen(fd, mode));
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}
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int
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fileargs_lstat(fileargs_t *fa, const char *name, struct stat *sb)
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{
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nvlist_t *nvl;
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const void *buf;
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size_t size;
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char *cmd;
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assert(fa != NULL);
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assert(fa->fa_magic == FILEARGS_MAGIC);
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if (name == NULL) {
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errno = EINVAL;
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return (-1);
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}
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if (sb == NULL) {
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errno = EFAULT;
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return (-1);
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}
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if (fa->fa_chann == NULL) {
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errno = ENOTCAPABLE;
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return (-1);
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}
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if (fileargs_get_lstat_cache(fa, name, sb) != -1)
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return (0);
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nvl = fileargs_fetch(fa, name, "lstat");
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if (nvl == NULL)
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return (-1);
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buf = nvlist_get_binary(nvl, "stat", &size);
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assert(size == sizeof(*sb));
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memcpy(sb, buf, size);
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cmd = nvlist_take_string(nvl, "cmd");
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if (strcmp(cmd, "cache") == 0)
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fileargs_set_cache(fa, nvl);
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else
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nvlist_destroy(nvl);
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free(cmd);
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return (0);
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}
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void
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fileargs_free(fileargs_t *fa)
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{
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@ -348,6 +433,7 @@ static void *cacheposition;
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static bool allcached;
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static const cap_rights_t *caprightsp;
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static int capflags;
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static int allowed_operations;
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static mode_t capmode;
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static int
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@ -382,6 +468,7 @@ fileargs_add_cache(nvlist_t *nvlout, const nvlist_t *limits,
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void *cookie;
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nvlist_t *new;
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const char *fname;
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struct stat sb;
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if ((capflags & O_CREAT) != 0) {
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allcached = true;
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@ -409,14 +496,25 @@ fileargs_add_cache(nvlist_t *nvlout, const nvlist_t *limits,
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continue;
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}
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fd = open_file(fname);
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if (fd < 0) {
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i--;
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continue;
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new = nvlist_create(NV_FLAG_NO_UNIQUE);
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if ((allowed_operations & FA_OPEN) != 0) {
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fd = open_file(fname);
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if (fd < 0) {
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i--;
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nvlist_destroy(new);
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continue;
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}
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nvlist_move_descriptor(new, "fd", fd);
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}
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if ((allowed_operations & FA_LSTAT) != 0) {
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if (lstat(fname, &sb) < 0) {
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i--;
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nvlist_destroy(new);
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continue;
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}
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nvlist_add_binary(new, "stat", &sb, sizeof(sb));
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}
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new = nvlist_create(NV_FLAG_NO_UNIQUE);
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nvlist_move_descriptor(new, "fd", fd);
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nvlist_add_nvlist(nvlout, fname, new);
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}
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cacheposition = cookie;
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@ -424,10 +522,13 @@ fileargs_add_cache(nvlist_t *nvlout, const nvlist_t *limits,
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}
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static bool
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fileargs_allowed(const nvlist_t *limits, const nvlist_t *request)
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fileargs_allowed(const nvlist_t *limits, const nvlist_t *request, int operation)
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{
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const char *name;
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if ((allowed_operations & operation) == 0)
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return (false);
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name = dnvlist_get_string(request, "name", NULL);
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if (name == NULL)
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return (false);
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@ -450,6 +551,7 @@ fileargs_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits)
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return (ENOTCAPABLE);
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capflags = (int)dnvlist_get_number(newlimits, "flags", 0);
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allowed_operations = (int)dnvlist_get_number(newlimits, "operations", 0);
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if ((capflags & O_CREAT) != 0)
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capmode = (mode_t)nvlist_get_number(newlimits, "mode");
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else
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@ -460,6 +562,37 @@ fileargs_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits)
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return (0);
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}
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static int
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fileargs_command_lstat(const nvlist_t *limits, nvlist_t *nvlin,
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nvlist_t *nvlout)
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{
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int stat;
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const char *name;
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struct stat sb;
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if (limits == NULL)
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return (ENOTCAPABLE);
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if (!fileargs_allowed(limits, nvlin, FA_LSTAT))
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return (ENOTCAPABLE);
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name = nvlist_get_string(nvlin, "name");
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stat = lstat(name, &sb);
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if (stat < 0)
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return (errno);
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if (!allcached && (lastname == NULL ||
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strcmp(name, lastname) == 0)) {
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nvlist_add_string(nvlout, "cmd", "cache");
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fileargs_add_cache(nvlout, limits, name);
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} else {
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nvlist_add_string(nvlout, "cmd", "lstat");
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}
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nvlist_add_binary(nvlout, "stat", &sb, sizeof(sb));
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return (0);
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}
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static int
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fileargs_command_open(const nvlist_t *limits, nvlist_t *nvlin,
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nvlist_t *nvlout)
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@ -470,7 +603,7 @@ fileargs_command_open(const nvlist_t *limits, nvlist_t *nvlin,
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if (limits == NULL)
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return (ENOTCAPABLE);
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if (!fileargs_allowed(limits, nvlin))
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if (!fileargs_allowed(limits, nvlin, FA_OPEN))
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return (ENOTCAPABLE);
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name = nvlist_get_string(nvlin, "name");
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@ -498,6 +631,9 @@ fileargs_command(const char *cmd, const nvlist_t *limits,
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if (strcmp(cmd, "open") == 0)
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return (fileargs_command_open(limits, nvlin, nvlout));
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if (strcmp(cmd, "lstat") == 0)
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return (fileargs_command_lstat(limits, nvlin, nvlout));
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return (EINVAL);
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}
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@ -36,16 +36,21 @@
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#include <stdbool.h>
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#define FA_OPEN 1
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#define FA_LSTAT 2
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#ifdef WITH_CASPER
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struct fileargs;
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typedef struct fileargs fileargs_t;
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struct stat;
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fileargs_t *fileargs_init(int argc, char *argv[], int flags, mode_t mode,
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cap_rights_t *rightsp);
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cap_rights_t *rightsp, int operations);
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fileargs_t *fileargs_cinit(cap_channel_t *cas, int argc, char *argv[],
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int flags, mode_t mode, cap_rights_t *rightsp);
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int flags, mode_t mode, cap_rights_t *rightsp, int operations);
|
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fileargs_t *fileargs_initnv(nvlist_t *limits);
|
||||
fileargs_t *fileargs_cinitnv(cap_channel_t *cas, nvlist_t *limits);
|
||||
int fileargs_lstat(fileargs_t *fa, const char *name, struct stat *sb);
|
||||
int fileargs_open(fileargs_t *fa, const char *name);
|
||||
void fileargs_free(fileargs_t *fa);
|
||||
FILE *fileargs_fopen(fileargs_t *fa, const char *name, const char *mode);
|
||||
@ -57,7 +62,7 @@ typedef struct fileargs {
|
||||
|
||||
static inline fileargs_t *
|
||||
fileargs_init(int argc __unused, char *argv[] __unused, int flags, mode_t mode,
|
||||
cap_rights_t *rightsp __unused) {
|
||||
cap_rights_t *rightsp __unused, int operations __unused) {
|
||||
fileargs_t *fa;
|
||||
|
||||
fa = malloc(sizeof(*fa));
|
||||
@ -71,10 +76,10 @@ fileargs_init(int argc __unused, char *argv[] __unused, int flags, mode_t mode,
|
||||
|
||||
static inline fileargs_t *
|
||||
fileargs_cinit(cap_channel_t *cas __unused, int argc, char *argv[], int flags,
|
||||
mode_t mode, cap_rights_t *rightsp)
|
||||
mode_t mode, cap_rights_t *rightsp, int operations)
|
||||
{
|
||||
|
||||
return (fileargs_init(argc, argv, flags, mode, rightsp));
|
||||
return (fileargs_init(argc, argv, flags, mode, rightsp, operations));
|
||||
}
|
||||
|
||||
static inline fileargs_t *
|
||||
@ -85,7 +90,8 @@ fileargs_initnv(nvlist_t *limits)
|
||||
fa = fileargs_init(0, NULL,
|
||||
nvlist_get_number(limits, "flags"),
|
||||
dnvlist_get_number(limits, "mode", 0),
|
||||
NULL);
|
||||
NULL,
|
||||
nvlist_get_number(limits, "operations"));
|
||||
nvlist_destroy(limits);
|
||||
|
||||
return (fa);
|
||||
@ -98,6 +104,8 @@ fileargs_cinitnv(cap_channel_t *cas __unused, nvlist_t *limits)
|
||||
return (fileargs_initnv(limits));
|
||||
}
|
||||
|
||||
#define fileargs_lstat(fa, name, sb) \
|
||||
lstat(name, sb)
|
||||
#define fileargs_open(fa, name) \
|
||||
open(name, fa->fa_flags, fa->fa_mode)
|
||||
#define fileargs_fopen(fa, name, mode) \
|
||||
|
||||
Loading…
Reference in New Issue
Block a user