| Message ID | 1245998284.6278.99.camel@localhost (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Ram Pai schrieb: > Problem: It is impossible to feed filenames with the character colon because > qemu interprets such names as a protocol. For example a filename scsi:0, is > interpreted as a protocol by name "scsi". > > This patch allows user to espace colon characters. For example the above > filename can now be expressed either as 'scsi\:0' or as file:scsi:0 > > anything following the "file:" tag is interpreted verbatim. However if "file:" > tag is omitted then any colon characters in the string must be escaped using > backslash. > > Here are couple of examples: > > scsi\:0\:abc is a local file scsi:0:abc > http\://myweb is a local file by name http://myweb > file:scsi:0:abc is a local file scsi:0:abc > file:http://myweb is a local file by name http://myweb > > Changelog w.r.t to iteration 1: > 1) removes flexibility added to nbd semantics eg -- nbd:\::9999 > 2) introduce the "file:" protocol to indicate local file > > NOTE: no code changes are needed to handle commas in a filename. As > always a comma has to be escaped by a preceding comma. > > > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > ----------------------------------------------------------------------- > > block.c | 16 ++++++---------- > block/raw-posix.c | 30 +++++++++++++++++++++++------- > cutils.c | 26 ++++++++++++++++++++++++++ > qemu-common.h | 1 + > 4 files changed, 56 insertions(+), 17 deletions(-) Okay, so some points beforehand: This is a change that should be made in upstream qemu, not qemu-kvm. So you should base your patch on qemu, it currently doesn't apply cleanly there. Also, please take a look at the CODING_STYLE file. Whitespace and braces are the points I noticed, maybe there are more. > diff --git a/block.c b/block.c > index aca5a6d..0064e22 100644 > --- a/block.c > +++ b/block.c > @@ -225,22 +225,18 @@ static BlockDriver *find_protocol(const char *filename) > { > BlockDriver *drv1; > char protocol[128]; > - int len; > - const char *p; > + const char *f; > + int len = strnlen(filename, 128); > > #ifdef _WIN32 > if (is_windows_drive(filename) || > is_windows_drive_prefix(filename)) > return bdrv_find_format("raw"); > #endif > - p = strchr(filename, ':'); > - if (!p) > - return bdrv_find_format("raw"); > - len = p - filename; > - if (len > sizeof(protocol) - 1) > - len = sizeof(protocol) - 1; > - memcpy(protocol, filename, len); > - protocol[len] = '\0'; > + f = fill_token(protocol, len, filename, ':'); > + if (*f != ':' || !strcmp(protocol, "file")) > + return bdrv_find_format("raw"); There is no reason to special-case "file:". You should just set bdrv_raw.protocol_name = "file" and let the generic code handle it. > + > for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) { > if (drv1->protocol_name && > !strcmp(drv1->protocol_name, protocol)) > diff --git a/block/raw-posix.c b/block/raw-posix.c > index 41bfa37..03d6581 100644 > --- a/block/raw-posix.c > +++ b/block/raw-posix.c > @@ -124,6 +124,22 @@ static int fd_open(BlockDriverState *bs); > static int cdrom_reopen(BlockDriverState *bs); > #endif > > +static int _open(const char *filename, int flags, ...) > +{ > + char myfile[PATH_MAX]; > + const char *f; > + va_list ap; > + va_start(ap, flags); > + > + if (!strstart(filename, "file:", &f)) { > + fill_token(myfile, PATH_MAX, filename, '\0'); > + return open(myfile, flags, ap); > + } else { > + return open(f, flags, ap); > + } > +} Passing ap to open doesn't look quite right to me... > + > + > static int raw_open_common(BlockDriverState *bs, const char *filename, > int flags) > { > @@ -151,7 +167,7 @@ static int raw_open_common(BlockDriverState *bs, const char *filename, > s->open_flags |= O_DSYNC; > > s->fd = -1; > - fd = open(filename, s->open_flags, 0644); > + fd = _open(filename, s->open_flags, 0644); > if (fd < 0) { > ret = -errno; > if (ret == -EROFS) > @@ -844,7 +860,7 @@ static int raw_create(const char *filename, QEMUOptionParameter *options) > options++; > } > > - fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, > + fd = _open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, > 0644); > if (fd < 0) > return -EIO; > @@ -985,7 +1001,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags) > if ( bsdPath[ 0 ] != '\0' ) { > strcat(bsdPath,"s0"); > /* some CDs don't have a partition 0 */ > - fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE); > + fd = _open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE); > if (fd < 0) { > bsdPath[strlen(bsdPath)-1] = '1'; > } else { > @@ -1037,7 +1053,7 @@ static int fd_open(BlockDriverState *bs) > #endif > return -EIO; > } > - s->fd = open(bs->filename, s->open_flags & ~O_NONBLOCK); > + s->fd = _open(bs->filename, s->open_flags & ~O_NONBLOCK); > if (s->fd < 0) { > s->fd_error_time = qemu_get_clock(rt_clock); > s->fd_got_error = 1; > @@ -1133,7 +1149,7 @@ static int hdev_create(const char *filename, QEMUOptionParameter *options) > options++; > } > > - fd = open(filename, O_WRONLY | O_BINARY); > + fd = _open(filename, O_WRONLY | O_BINARY); > if (fd < 0) > return -EIO; > > @@ -1239,7 +1255,7 @@ static int floppy_eject(BlockDriverState *bs, int eject_flag) > close(s->fd); > s->fd = -1; > } > - fd = open(bs->filename, s->open_flags | O_NONBLOCK); > + fd = _open(bs->filename, s->open_flags | O_NONBLOCK); > if (fd >= 0) { > if (ioctl(fd, FDEJECT, 0) < 0) > perror("FDEJECT"); > @@ -1399,7 +1415,7 @@ static int cdrom_reopen(BlockDriverState *bs) > */ > if (s->fd >= 0) > close(s->fd); > - fd = open(bs->filename, s->open_flags, 0644); > + fd = _open(bs->filename, s->open_flags, 0644); > if (fd < 0) { > s->fd = -1; > return -EIO; I don't like this, honestly. Is there no chance to do the unescaping at one central place instead of n - 1 place and forgetting the nth one? > diff --git a/cutils.c b/cutils.c > index 6ea0c49..f6d5bf5 100644 > --- a/cutils.c > +++ b/cutils.c > @@ -24,6 +24,32 @@ > #include "qemu-common.h" > #include "host-utils.h" > > +/* > + * fill buffer 'buff' with the contents of the string 'str' delimited by > + * the character 'c'. If delimiter not found in 'len' bytes of the string > + * assume '\0' as the default delimiter. > + * Return pointer to the delimiting character > + */ > +const char *fill_token(char *buf, int len, const char *str, char c) > +{ > + const char *p=str; > + char *q=buf; > + > + while (p < str+len) { > + if (*p == c) > + break; > + if (*p == '\\' ) { > + p++; > + if (*p == '\0') > + break; > + } > + *q++ = *p++; > + } > + *q='\0'; If we left the while loop because len is exhausted, this is a buffer overflow. In the other case, you will read beyond the end of str because you only check for \0 after a backslash (actually, your code doesn't, but future callers will as it is highly unusual for a string function to ignore \0). > + return p; > +} > + > + > void pstrcpy(char *buf, int buf_size, const char *str) > { > int c; > diff --git a/qemu-common.h b/qemu-common.h > index 2dcb224..8916502 100644 > --- a/qemu-common.h > +++ b/qemu-common.h > @@ -104,6 +104,7 @@ void qemu_get_timedate(struct tm *tm, int offset); > int qemu_timedate_diff(struct tm *tm); > > /* cutils.c */ > +const char *fill_token(char *buf, int buf_size, const char *str, char); > void pstrcpy(char *buf, int buf_size, const char *str); > char *pstrcat(char *buf, int buf_size, const char *s); > int strstart(const char *str, const char *val, const char **ptr); > > Kevin -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/block.c b/block.c index aca5a6d..0064e22 100644 --- a/block.c +++ b/block.c @@ -225,22 +225,18 @@ static BlockDriver *find_protocol(const char *filename) { BlockDriver *drv1; char protocol[128]; - int len; - const char *p; + const char *f; + int len = strnlen(filename, 128); #ifdef _WIN32 if (is_windows_drive(filename) || is_windows_drive_prefix(filename)) return bdrv_find_format("raw"); #endif - p = strchr(filename, ':'); - if (!p) - return bdrv_find_format("raw"); - len = p - filename; - if (len > sizeof(protocol) - 1) - len = sizeof(protocol) - 1; - memcpy(protocol, filename, len); - protocol[len] = '\0'; + f = fill_token(protocol, len, filename, ':'); + if (*f != ':' || !strcmp(protocol, "file")) + return bdrv_find_format("raw"); + for(drv1 = first_drv; drv1 != NULL; drv1 = drv1->next) { if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) diff --git a/block/raw-posix.c b/block/raw-posix.c index 41bfa37..03d6581 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -124,6 +124,22 @@ static int fd_open(BlockDriverState *bs); static int cdrom_reopen(BlockDriverState *bs); #endif +static int _open(const char *filename, int flags, ...) +{ + char myfile[PATH_MAX]; + const char *f; + va_list ap; + va_start(ap, flags); + + if (!strstart(filename, "file:", &f)) { + fill_token(myfile, PATH_MAX, filename, '\0'); + return open(myfile, flags, ap); + } else { + return open(f, flags, ap); + } +} + + static int raw_open_common(BlockDriverState *bs, const char *filename, int flags) { @@ -151,7 +167,7 @@ static int raw_open_common(BlockDriverState *bs, const char *filename, s->open_flags |= O_DSYNC; s->fd = -1; - fd = open(filename, s->open_flags, 0644); + fd = _open(filename, s->open_flags, 0644); if (fd < 0) { ret = -errno; if (ret == -EROFS) @@ -844,7 +860,7 @@ static int raw_create(const char *filename, QEMUOptionParameter *options) options++; } - fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, + fd = _open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); if (fd < 0) return -EIO; @@ -985,7 +1001,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags) if ( bsdPath[ 0 ] != '\0' ) { strcat(bsdPath,"s0"); /* some CDs don't have a partition 0 */ - fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE); + fd = _open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE); if (fd < 0) { bsdPath[strlen(bsdPath)-1] = '1'; } else { @@ -1037,7 +1053,7 @@ static int fd_open(BlockDriverState *bs) #endif return -EIO; } - s->fd = open(bs->filename, s->open_flags & ~O_NONBLOCK); + s->fd = _open(bs->filename, s->open_flags & ~O_NONBLOCK); if (s->fd < 0) { s->fd_error_time = qemu_get_clock(rt_clock); s->fd_got_error = 1; @@ -1133,7 +1149,7 @@ static int hdev_create(const char *filename, QEMUOptionParameter *options) options++; } - fd = open(filename, O_WRONLY | O_BINARY); + fd = _open(filename, O_WRONLY | O_BINARY); if (fd < 0) return -EIO; @@ -1239,7 +1255,7 @@ static int floppy_eject(BlockDriverState *bs, int eject_flag) close(s->fd); s->fd = -1; } - fd = open(bs->filename, s->open_flags | O_NONBLOCK); + fd = _open(bs->filename, s->open_flags | O_NONBLOCK); if (fd >= 0) { if (ioctl(fd, FDEJECT, 0) < 0) perror("FDEJECT"); @@ -1399,7 +1415,7 @@ static int cdrom_reopen(BlockDriverState *bs) */ if (s->fd >= 0) close(s->fd); - fd = open(bs->filename, s->open_flags, 0644); + fd = _open(bs->filename, s->open_flags, 0644); if (fd < 0) { s->fd = -1; return -EIO; diff --git a/cutils.c b/cutils.c index 6ea0c49..f6d5bf5 100644 --- a/cutils.c +++ b/cutils.c @@ -24,6 +24,32 @@ #include "qemu-common.h" #include "host-utils.h" +/* + * fill buffer 'buff' with the contents of the string 'str' delimited by + * the character 'c'. If delimiter not found in 'len' bytes of the string + * assume '\0' as the default delimiter. + * Return pointer to the delimiting character + */ +const char *fill_token(char *buf, int len, const char *str, char c) +{ + const char *p=str; + char *q=buf; + + while (p < str+len) { + if (*p == c) + break; + if (*p == '\\' ) { + p++; + if (*p == '\0') + break; + } + *q++ = *p++; + } + *q='\0'; + return p; +} + + void pstrcpy(char *buf, int buf_size, const char *str) { int c; diff --git a/qemu-common.h b/qemu-common.h index 2dcb224..8916502 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -104,6 +104,7 @@ void qemu_get_timedate(struct tm *tm, int offset); int qemu_timedate_diff(struct tm *tm); /* cutils.c */ +const char *fill_token(char *buf, int buf_size, const char *str, char); void pstrcpy(char *buf, int buf_size, const char *str); char *pstrcat(char *buf, int buf_size, const char *s); int strstart(const char *str, const char *val, const char **ptr);
Problem: It is impossible to feed filenames with the character colon because qemu interprets such names as a protocol. For example a filename scsi:0, is interpreted as a protocol by name "scsi". This patch allows user to espace colon characters. For example the above filename can now be expressed either as 'scsi\:0' or as file:scsi:0 anything following the "file:" tag is interpreted verbatim. However if "file:" tag is omitted then any colon characters in the string must be escaped using backslash. Here are couple of examples: scsi\:0\:abc is a local file scsi:0:abc http\://myweb is a local file by name http://myweb file:scsi:0:abc is a local file scsi:0:abc file:http://myweb is a local file by name http://myweb Changelog w.r.t to iteration 1: 1) removes flexibility added to nbd semantics eg -- nbd:\::9999 2) introduce the "file:" protocol to indicate local file NOTE: no code changes are needed to handle commas in a filename. As always a comma has to be escaped by a preceding comma. Signed-off-by: Ram Pai <linuxram@us.ibm.com> ----------------------------------------------------------------------- block.c | 16 ++++++---------- block/raw-posix.c | 30 +++++++++++++++++++++++------- cutils.c | 26 ++++++++++++++++++++++++++ qemu-common.h | 1 + 4 files changed, 56 insertions(+), 17 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html