Re: git: f80babf906b7 - main - kern_sysctl: Make name2oid() non-destructive to the name
Date: Sat, 23 Sep 2023 16:26:52 UTC
Good job ! > On Sep 24, 2023, at 12:23 AM, Alexander Motin <mav@FreeBSD.org> wrote: > > The branch main has been updated by mav: > > URL: https://cgit.FreeBSD.org/src/commit/?id=f80babf906b7be51b2a031ef26525893c7bf4e31 > > commit f80babf906b7be51b2a031ef26525893c7bf4e31 > Author: Alexander Motin <mav@FreeBSD.org> > AuthorDate: 2023-09-23 16:13:46 +0000 > Commit: Alexander Motin <mav@FreeBSD.org> > CommitDate: 2023-09-23 16:13:46 +0000 > > kern_sysctl: Make name2oid() non-destructive to the name > > It is not the first time I see it panicking while trying to modify > const memory. Lets make it safer and easier to use. While there, > mark few functions using it also const. > > MFC after: 10 days > --- > sys/kern/kern_sysctl.c | 34 +++++++++++++++++++++++++++------- > 1 file changed, 27 insertions(+), 7 deletions(-) > > diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c > index 780eb6099b07..a4bfe8e21aed 100644 > --- a/sys/kern/kern_sysctl.c > +++ b/sys/kern/kern_sysctl.c > @@ -127,7 +127,7 @@ static int sysctl_remove_oid_locked(struct sysctl_oid *oidp, int del, > int recurse); > static int sysctl_old_kernel(struct sysctl_req *, const void *, size_t); > static int sysctl_new_kernel(struct sysctl_req *, void *, size_t); > -static int name2oid(char *, int *, int *, struct sysctl_oid **); > +static int name2oid(const char *, int *, int *, struct sysctl_oid **); > > static struct sysctl_oid * > sysctl_find_oidname(const char *name, struct sysctl_oid_list *list) > @@ -143,6 +143,21 @@ sysctl_find_oidname(const char *name, struct sysctl_oid_list *list) > return (NULL); > } > > +static struct sysctl_oid * > +sysctl_find_oidnamelen(const char *name, size_t len, > + struct sysctl_oid_list *list) > +{ > + struct sysctl_oid *oidp; > + > + SYSCTL_ASSERT_LOCKED(); > + SYSCTL_FOREACH(oidp, list) { > + if (strncmp(oidp->oid_name, name, len) == 0 && > + oidp->oid_name[len] == '\0') > + return (oidp); > + } > + return (NULL); > +} > + > /* > * Initialization of the MIB tree. > * > @@ -978,7 +993,7 @@ SYSINIT(sysctl, SI_SUB_KMEM, SI_ORDER_FIRST, sysctl_register_all, NULL); > > #ifdef VIMAGE > static void > -sysctl_setenv_vnet(void *arg __unused, char *name) > +sysctl_setenv_vnet(void *arg __unused, const char *name) > { > struct sysctl_oid *oidp; > int oid[CTL_MAXNAME]; > @@ -1001,7 +1016,7 @@ out: > } > > static void > -sysctl_unsetenv_vnet(void *arg __unused, char *name) > +sysctl_unsetenv_vnet(void *arg __unused, const char *name) > { > struct sysctl_oid *oidp; > int oid[CTL_MAXNAME]; > @@ -1419,21 +1434,26 @@ static SYSCTL_NODE(_sysctl, CTL_SYSCTL_NEXTNOSKIP, nextnoskip, CTLFLAG_RD | > CTLFLAG_MPSAFE | CTLFLAG_CAPRD, sysctl_sysctl_next, ""); > > static int > -name2oid(char *name, int *oid, int *len, struct sysctl_oid **oidpp) > +name2oid(const char *name, int *oid, int *len, struct sysctl_oid **oidpp) > { > struct sysctl_oid *oidp; > struct sysctl_oid_list *lsp = &sysctl__children; > + const char *n; > > SYSCTL_ASSERT_LOCKED(); > > for (*len = 0; *len < CTL_MAXNAME;) { > - oidp = sysctl_find_oidname(strsep(&name, "."), lsp); > + n = strchrnul(name, '.'); > + oidp = sysctl_find_oidnamelen(name, n - name, lsp); > if (oidp == NULL) > return (ENOENT); > *oid++ = oidp->oid_number; > (*len)++; > > - if (name == NULL || *name == '\0') { > + name = n; > + if (*name == '.') > + name++; > + if (*name == '\0') { > if (oidpp) > *oidpp = oidp; > return (0); > @@ -2999,7 +3019,7 @@ db_show_sysctl_all(int *oid, size_t len, int flags) > * Show a sysctl by its user facing string > */ > static int > -db_sysctlbyname(char *name, int flags) > +db_sysctlbyname(const char *name, int flags) > { > struct sysctl_oid *oidp; > int oid[CTL_MAXNAME];