| Message ID | 20230203091809.14478-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Mini-OS: ad minimal 9pfs support | expand |
Juergen Gross, le ven. 03 févr. 2023 10:18:04 +0100, a ecrit: > Add the concept of mount points to Mini-OS. A mount point is a path > associated with a device pointer and an open() callback. A mount point > can be either a file (e.g. "/dev/mem") or a directory ("/var/log"). > > This allows to replace the special casing in the generic open() > handling with a generic mount point handling. > > Prepare the open() callbacks to support creating new files by adding a > mode parameter. > > Additionally add a close() prototype to include/lib.h, as it is missing > today. > > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Thanks! > --- > include/lib.h | 9 ++++++ > lib/sys.c | 80 +++++++++++++++++++++++++++++++++++++++------------ > 2 files changed, 70 insertions(+), 19 deletions(-) > > diff --git a/include/lib.h b/include/lib.h > index bec99646..36d94ec4 100644 > --- a/include/lib.h > +++ b/include/lib.h > @@ -187,6 +187,13 @@ struct file_ops { > bool (*select_wr)(struct file *file); > }; > > +struct mount_point { > + const char *path; > + int (*open)(struct mount_point *mnt, const char *pathname, int flags, > + mode_t mode); > + void *dev; > +}; > + > unsigned int alloc_file_type(const struct file_ops *ops); > > off_t lseek_default(struct file *file, off_t offset, int whence); > @@ -198,6 +205,8 @@ int alloc_fd(unsigned int type); > void close_all_files(void); > extern struct thread *main_thread; > void sparse(unsigned long data, size_t size); > + > +int close(int fd); > #endif > > #endif /* _LIB_H_ */ > diff --git a/lib/sys.c b/lib/sys.c > index 8f8a3de2..1475c621 100644 > --- a/lib/sys.c > +++ b/lib/sys.c > @@ -263,11 +263,6 @@ char *getcwd(char *buf, size_t size) > return buf; > } > > -#define LOG_PATH "/var/log/" > -#define SAVE_PATH "/var/lib/xen" > -#define SAVE_CONSOLE 1 > -#define RESTORE_CONSOLE 2 > - > int mkdir(const char *pathname, mode_t mode) > { > errno = EIO; > @@ -286,18 +281,30 @@ int posix_openpt(int flags) > return fd; > } > > +static int open_pt(struct mount_point *mnt, const char *pathname, int flags, > + mode_t mode) > +{ > + return posix_openpt(flags); > +} > + > int open_savefile(const char *path, int save) > { > int fd; > char nodename[64]; > > - snprintf(nodename, sizeof(nodename), "device/console/%d", save ? SAVE_CONSOLE : RESTORE_CONSOLE); > + snprintf(nodename, sizeof(nodename), "device/console/%d", save ? 1 : 2); > > fd = open_consfront(nodename); > printk("fd(%d) = open_savefile\n", fd); > > return fd; > } > + > +static int open_save(struct mount_point *mnt, const char *pathname, int flags, > + mode_t mode) > +{ > + return open_savefile(pathname, flags & O_WRONLY); > +} > #else > int posix_openpt(int flags) > { > @@ -311,24 +318,59 @@ int open_savefile(const char *path, int save) > } > #endif > > -int open(const char *pathname, int flags, ...) > +static int open_log(struct mount_point *mnt, const char *pathname, int flags, > + mode_t mode) > { > int fd; > + > /* Ugly, but fine. */ > - if (!strncmp(pathname,LOG_PATH,strlen(LOG_PATH))) { > - fd = alloc_fd(FTYPE_CONSOLE); > - printk("open(%s) -> %d\n", pathname, fd); > - return fd; > + fd = alloc_fd(FTYPE_CONSOLE); > + printk("open(%s) -> %d\n", pathname, fd); > + return fd; > +} > + > +static int open_mem(struct mount_point *mnt, const char *pathname, int flags, > + mode_t mode) > +{ > + int fd; > + > + fd = alloc_fd(FTYPE_MEM); > + printk("open(%s) -> %d\n", pathname, fd); > + return fd; > +} > + > +static struct mount_point mount_points[] = { > + { .path = "/var/log", .open = open_log, .dev = NULL }, > + { .path = "/dev/mem", .open = open_mem, .dev = NULL }, > +#ifdef CONFIG_CONSFRONT > + { .path = "/dev/ptmx", .open = open_pt, .dev = NULL }, > + { .path = "/var/lib/xen", .open = open_save, .dev = NULL }, > +#endif > +}; > + > +int open(const char *pathname, int flags, ...) > +{ > + unsigned int m, mlen; > + struct mount_point *mnt; > + mode_t mode = 0; > + va_list ap; > + > + if ( flags & O_CREAT ) > + { > + va_start(ap, flags); > + mode = va_arg(ap, mode_t); > + va_end(ap); > } > - if (!strncmp(pathname, "/dev/mem", strlen("/dev/mem"))) { > - fd = alloc_fd(FTYPE_MEM); > - printk("open(/dev/mem) -> %d\n", fd); > - return fd; > + > + for ( m = 0; m < ARRAY_SIZE(mount_points); m++ ) > + { > + mnt = mount_points + m; > + mlen = strlen(mnt->path); > + if ( !strncmp(pathname, mnt->path, mlen) && > + (pathname[mlen] == '/' || pathname[mlen] == 0) ) > + return mnt->open(mnt, pathname, flags, mode); > } > - if (!strncmp(pathname, "/dev/ptmx", strlen("/dev/ptmx"))) > - return posix_openpt(flags); > - if (!strncmp(pathname,SAVE_PATH,strlen(SAVE_PATH))) > - return open_savefile(pathname, flags & O_WRONLY); > + > errno = EIO; > return -1; > } > -- > 2.35.3 >
Juergen Gross, le ven. 03 févr. 2023 10:18:04 +0100, a ecrit: > +int open(const char *pathname, int flags, ...) > +{ > + unsigned int m, mlen; > + struct mount_point *mnt; > + mode_t mode = 0; > + va_list ap; > + > + if ( flags & O_CREAT ) > + { > + va_start(ap, flags); > + mode = va_arg(ap, mode_t); > + va_end(ap); > } > - if (!strncmp(pathname, "/dev/mem", strlen("/dev/mem"))) { > - fd = alloc_fd(FTYPE_MEM); > - printk("open(/dev/mem) -> %d\n", fd); > - return fd; > + > + for ( m = 0; m < ARRAY_SIZE(mount_points); m++ ) > + { > + mnt = mount_points + m; > + mlen = strlen(mnt->path); > + if ( !strncmp(pathname, mnt->path, mlen) && > + (pathname[mlen] == '/' || pathname[mlen] == 0) ) > + return mnt->open(mnt, pathname, flags, mode); Thinking about it more: don't we want to pass pathname+mlen? So that the open function doesn't have to care where it's mounted. Samuel
On 05.02.23 13:45, Samuel Thibault wrote: > Juergen Gross, le ven. 03 févr. 2023 10:18:04 +0100, a ecrit: >> +int open(const char *pathname, int flags, ...) >> +{ >> + unsigned int m, mlen; >> + struct mount_point *mnt; >> + mode_t mode = 0; >> + va_list ap; >> + >> + if ( flags & O_CREAT ) >> + { >> + va_start(ap, flags); >> + mode = va_arg(ap, mode_t); >> + va_end(ap); >> } >> - if (!strncmp(pathname, "/dev/mem", strlen("/dev/mem"))) { >> - fd = alloc_fd(FTYPE_MEM); >> - printk("open(/dev/mem) -> %d\n", fd); >> - return fd; >> + >> + for ( m = 0; m < ARRAY_SIZE(mount_points); m++ ) >> + { >> + mnt = mount_points + m; >> + mlen = strlen(mnt->path); >> + if ( !strncmp(pathname, mnt->path, mlen) && >> + (pathname[mlen] == '/' || pathname[mlen] == 0) ) >> + return mnt->open(mnt, pathname, flags, mode); > > Thinking about it more: don't we want to pass pathname+mlen? > > So that the open function doesn't have to care where it's mounted. I think both variants have their pros and cons. As the open functions have the mount point available via the mnt parameter I can change it. Juergen
diff --git a/include/lib.h b/include/lib.h index bec99646..36d94ec4 100644 --- a/include/lib.h +++ b/include/lib.h @@ -187,6 +187,13 @@ struct file_ops { bool (*select_wr)(struct file *file); }; +struct mount_point { + const char *path; + int (*open)(struct mount_point *mnt, const char *pathname, int flags, + mode_t mode); + void *dev; +}; + unsigned int alloc_file_type(const struct file_ops *ops); off_t lseek_default(struct file *file, off_t offset, int whence); @@ -198,6 +205,8 @@ int alloc_fd(unsigned int type); void close_all_files(void); extern struct thread *main_thread; void sparse(unsigned long data, size_t size); + +int close(int fd); #endif #endif /* _LIB_H_ */ diff --git a/lib/sys.c b/lib/sys.c index 8f8a3de2..1475c621 100644 --- a/lib/sys.c +++ b/lib/sys.c @@ -263,11 +263,6 @@ char *getcwd(char *buf, size_t size) return buf; } -#define LOG_PATH "/var/log/" -#define SAVE_PATH "/var/lib/xen" -#define SAVE_CONSOLE 1 -#define RESTORE_CONSOLE 2 - int mkdir(const char *pathname, mode_t mode) { errno = EIO; @@ -286,18 +281,30 @@ int posix_openpt(int flags) return fd; } +static int open_pt(struct mount_point *mnt, const char *pathname, int flags, + mode_t mode) +{ + return posix_openpt(flags); +} + int open_savefile(const char *path, int save) { int fd; char nodename[64]; - snprintf(nodename, sizeof(nodename), "device/console/%d", save ? SAVE_CONSOLE : RESTORE_CONSOLE); + snprintf(nodename, sizeof(nodename), "device/console/%d", save ? 1 : 2); fd = open_consfront(nodename); printk("fd(%d) = open_savefile\n", fd); return fd; } + +static int open_save(struct mount_point *mnt, const char *pathname, int flags, + mode_t mode) +{ + return open_savefile(pathname, flags & O_WRONLY); +} #else int posix_openpt(int flags) { @@ -311,24 +318,59 @@ int open_savefile(const char *path, int save) } #endif -int open(const char *pathname, int flags, ...) +static int open_log(struct mount_point *mnt, const char *pathname, int flags, + mode_t mode) { int fd; + /* Ugly, but fine. */ - if (!strncmp(pathname,LOG_PATH,strlen(LOG_PATH))) { - fd = alloc_fd(FTYPE_CONSOLE); - printk("open(%s) -> %d\n", pathname, fd); - return fd; + fd = alloc_fd(FTYPE_CONSOLE); + printk("open(%s) -> %d\n", pathname, fd); + return fd; +} + +static int open_mem(struct mount_point *mnt, const char *pathname, int flags, + mode_t mode) +{ + int fd; + + fd = alloc_fd(FTYPE_MEM); + printk("open(%s) -> %d\n", pathname, fd); + return fd; +} + +static struct mount_point mount_points[] = { + { .path = "/var/log", .open = open_log, .dev = NULL }, + { .path = "/dev/mem", .open = open_mem, .dev = NULL }, +#ifdef CONFIG_CONSFRONT + { .path = "/dev/ptmx", .open = open_pt, .dev = NULL }, + { .path = "/var/lib/xen", .open = open_save, .dev = NULL }, +#endif +}; + +int open(const char *pathname, int flags, ...) +{ + unsigned int m, mlen; + struct mount_point *mnt; + mode_t mode = 0; + va_list ap; + + if ( flags & O_CREAT ) + { + va_start(ap, flags); + mode = va_arg(ap, mode_t); + va_end(ap); } - if (!strncmp(pathname, "/dev/mem", strlen("/dev/mem"))) { - fd = alloc_fd(FTYPE_MEM); - printk("open(/dev/mem) -> %d\n", fd); - return fd; + + for ( m = 0; m < ARRAY_SIZE(mount_points); m++ ) + { + mnt = mount_points + m; + mlen = strlen(mnt->path); + if ( !strncmp(pathname, mnt->path, mlen) && + (pathname[mlen] == '/' || pathname[mlen] == 0) ) + return mnt->open(mnt, pathname, flags, mode); } - if (!strncmp(pathname, "/dev/ptmx", strlen("/dev/ptmx"))) - return posix_openpt(flags); - if (!strncmp(pathname,SAVE_PATH,strlen(SAVE_PATH))) - return open_savefile(pathname, flags & O_WRONLY); + errno = EIO; return -1; }
Add the concept of mount points to Mini-OS. A mount point is a path associated with a device pointer and an open() callback. A mount point can be either a file (e.g. "/dev/mem") or a directory ("/var/log"). This allows to replace the special casing in the generic open() handling with a generic mount point handling. Prepare the open() callbacks to support creating new files by adding a mode parameter. Additionally add a close() prototype to include/lib.h, as it is missing today. Signed-off-by: Juergen Gross <jgross@suse.com> --- include/lib.h | 9 ++++++ lib/sys.c | 80 +++++++++++++++++++++++++++++++++++++++------------ 2 files changed, 70 insertions(+), 19 deletions(-)