Re: [Qemu-devel] [PATCH] v6 revamp acpitable parsing and allow to specify complete (headerful) table

[TeLeMan <geleman@gmail.com>]

On Thu, May 12, 2011 at 10:44 PM, Michael Tokarev <mjt@tls.msk.ru> wrote:
> This patch almost rewrites acpi_table_add() function
> (but still leaves it using old get_param_value() interface).
> The result is that it's now possible to specify whole table
> (together with a header) in an external file, instead of just
> data portion, with a new file= parameter, but at the same time
> it's still possible to specify header fields as before.
>
> Now with the checkpatch.pl formatting fixes, thanks to
> Stefan Hajnoczi for suggestions, with changes from
> Isaku Yamahata, and with my further refinements.
>
> v5: rediffed against current qemu/master.
> v6: fix one "} else {" coding style defect
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  hw/acpi.c       |  291 ++++++++++++++++++++++++++++++++-----------------------
>  qemu-options.hx |    7 +-
>  2 files changed, 174 insertions(+), 124 deletions(-)
>
> diff --git a/hw/acpi.c b/hw/acpi.c
> index ad40fb4..b8cd866 100644
> --- a/hw/acpi.c
> +++ b/hw/acpi.c
> @@ -22,17 +22,29 @@
>
>  struct acpi_table_header
>  {
> -    char signature [4];    /* ACPI signature (4 ASCII characters) */
> +    uint16_t _length;         /* our length, not actual part of the hdr */
> +                              /* XXX why we have 2 length fields here? */
> +    char sig[4];              /* ACPI signature (4 ASCII characters) */
>      uint32_t length;          /* Length of table, in bytes, including header */
>      uint8_t revision;         /* ACPI Specification minor version # */
>      uint8_t checksum;         /* To make sum of entire table == 0 */
> -    char oem_id [6];       /* OEM identification */
> -    char oem_table_id [8]; /* OEM table identification */
> +    char oem_id[6];           /* OEM identification */
> +    char oem_table_id[8];     /* OEM table identification */
>      uint32_t oem_revision;    /* OEM revision number */
> -    char asl_compiler_id [4]; /* ASL compiler vendor ID */
> +    char asl_compiler_id[4];  /* ASL compiler vendor ID */
>      uint32_t asl_compiler_revision; /* ASL compiler revision number */
>  } __attribute__((packed));
>
> +#define ACPI_TABLE_HDR_SIZE sizeof(struct acpi_table_header)
> +#define ACPI_TABLE_PFX_SIZE sizeof(uint16_t)  /* size of the extra prefix */
> +
> +static const char dfl_hdr[ACPI_TABLE_HDR_SIZE] =
> +    "\0\0"                   /* fake _length (2) */
> +    "QEMU\0\0\0\0\1\0"       /* sig (4), len(4), revno (1), csum (1) */
> +    "QEMUQEQEMUQEMU\1\0\0\0" /* OEM id (6), table (8), revno (4) */
> +    "QEMU\1\0\0\0"           /* ASL compiler ID (4), version (4) */
> +    ;
> +
>  char *acpi_tables;
>  size_t acpi_tables_len;
>
> @@ -45,158 +57,191 @@ static int acpi_checksum(const uint8_t *data, int len)
>      return (-sum) & 0xff;
>  }
>
> +/* like strncpy() but zero-fills the tail of destination */
> +static void strzcpy(char *dst, const char *src, size_t size)
> +{
> +    size_t len = strlen(src);
> +    if (len >= size) {
> +        len = size;
> +    } else {
> +      memset(dst + len, 0, size - len);
> +    }
> +    memcpy(dst, src, len);
> +}
> +
> +/* XXX fixme: this function uses obsolete argument parsing interface */
>  int acpi_table_add(const char *t)
>  {
> -    static const char *dfl_id = "QEMUQEMU";
>      char buf[1024], *p, *f;
> -    struct acpi_table_header acpi_hdr;
>      unsigned long val;
> -    uint32_t length;
> -    struct acpi_table_header *acpi_hdr_p;
> -    size_t off;
> +    size_t len, start, allen;
> +    bool has_header;
> +    int changed;
> +    int r;
> +    struct acpi_table_header hdr;
> +
> +    r = 0;
> +    r |= get_param_value(buf, sizeof(buf), "data", t) ? 1 : 0;
> +    r |= get_param_value(buf, sizeof(buf), "file", t) ? 2 : 0;
> +    switch (r) {
> +    case 0:
> +        buf[0] = '\0';
> +    case 1:
> +        has_header = false;
> +        break;
> +    case 2:
> +        has_header = true;
> +        break;
> +    default:
> +        fprintf(stderr, "acpitable: both data and file are specified\n");
> +        return -1;
> +    }
>
> -    memset(&acpi_hdr, 0, sizeof(acpi_hdr));
> -
> -    if (get_param_value(buf, sizeof(buf), "sig", t)) {
> -        strncpy(acpi_hdr.signature, buf, 4);
> +    if (!acpi_tables) {
> +        allen = sizeof(uint16_t);
> +        acpi_tables = qemu_mallocz(allen);
>      } else {
> -        strncpy(acpi_hdr.signature, dfl_id, 4);
> +        allen = acpi_tables_len;
> +    }
> +
> +    start = allen;
> +    acpi_tables = qemu_realloc(acpi_tables, start + ACPI_TABLE_HDR_SIZE);
> +    allen += has_header ? ACPI_TABLE_PFX_SIZE : ACPI_TABLE_HDR_SIZE;
> +
> +    /* now read in the data files, reallocating buffer as needed */
> +
> +    for (f = strtok(buf, ":"); f; f = strtok(NULL, ":")) {
> +        int fd = open(f, O_RDONLY);

The acpi table is the binary file, so it should be opened by O_RDONLY
| O_BINARY.

> +
> +        if (fd < 0) {
> +            fprintf(stderr, "can't open file %s: %s\n", f, strerror(errno));
> +            return -1;
> +        }
> +
> +        for (;;) {
> +            char data[8192];
> +            r = read(fd, data, sizeof(data));
> +            if (r == 0) {
> +                break;
> +            } else if (r > 0) {
> +                acpi_tables = qemu_realloc(acpi_tables, allen + r);
> +                memcpy(acpi_tables + allen, data, r);
> +                allen += r;
> +            } else if (errno != EINTR) {
> +                fprintf(stderr, "can't read file %s: %s\n",
> +                        f, strerror(errno));
> +                close(fd);
> +                return -1;
> +            }
> +        }
> +
> +        close(fd);
> +    }
> +
> +    /* now fill in the header fields */
> +
> +    f = acpi_tables + start;   /* start of the table */
> +    changed = 0;
> +
> +    /* copy the header to temp place to align the fields */
> +    memcpy(&hdr, has_header ? f : dfl_hdr, ACPI_TABLE_HDR_SIZE);
> +
> +    /* length of the table minus our prefix */
> +    len = allen - start - ACPI_TABLE_PFX_SIZE;
> +
> +    hdr._length = cpu_to_le16(len);
> +
> +    if (get_param_value(buf, sizeof(buf), "sig", t)) {
> +        strzcpy(hdr.sig, buf, sizeof(hdr.sig));
> +        ++changed;
>      }
> +
> +    /* length of the table including header, in bytes */
> +    if (has_header) {
> +        /* check if actual length is correct */
> +        val = le32_to_cpu(hdr.length);
> +        if (val != len) {
> +            fprintf(stderr,
> +                "warning: acpitable has wrong length,"
> +                " header says %lu, actual size %u bytes\n",
> +                val, len);
> +            ++changed;
> +        }
> +    }
> +    /* we may avoid putting length here if has_header is true */
> +    hdr.length = cpu_to_le32(len);
> +
>      if (get_param_value(buf, sizeof(buf), "rev", t)) {
> -        val = strtoul(buf, &p, 10);
> -        if (val > 255 || *p != '\0')
> -            goto out;
> -    } else {
> -        val = 1;
> +        val = strtoul(buf, &p, 0);
> +        if (val > 255 || *p) {
> +            fprintf(stderr, "acpitable: \"rev=%s\" is invalid\n", buf);
> +            return -1;
> +        }
> +        hdr.revision = (uint8_t)val;
> +        ++changed;
>      }
> -    acpi_hdr.revision = (int8_t)val;
>
>      if (get_param_value(buf, sizeof(buf), "oem_id", t)) {
> -        strncpy(acpi_hdr.oem_id, buf, 6);
> -    } else {
> -        strncpy(acpi_hdr.oem_id, dfl_id, 6);
> +        strzcpy(hdr.oem_id, buf, sizeof(hdr.oem_id));
> +        ++changed;
>      }
>
>      if (get_param_value(buf, sizeof(buf), "oem_table_id", t)) {
> -        strncpy(acpi_hdr.oem_table_id, buf, 8);
> -    } else {
> -        strncpy(acpi_hdr.oem_table_id, dfl_id, 8);
> +        strzcpy(hdr.oem_table_id, buf, sizeof(hdr.oem_table_id));
> +        ++changed;
>      }
>
>      if (get_param_value(buf, sizeof(buf), "oem_rev", t)) {
> -        val = strtol(buf, &p, 10);
> -        if(*p != '\0')
> -            goto out;
> -    } else {
> -        val = 1;
> +        val = strtol(buf, &p, 0);
> +        if (*p) {
> +            fprintf(stderr, "acpitable: \"oem_rev=%s\" is invalid\n", buf);
> +            return -1;
> +        }
> +        hdr.oem_revision = cpu_to_le32(val);
> +        ++changed;
>      }
> -    acpi_hdr.oem_revision = cpu_to_le32(val);
>
>      if (get_param_value(buf, sizeof(buf), "asl_compiler_id", t)) {
> -        strncpy(acpi_hdr.asl_compiler_id, buf, 4);
> -    } else {
> -        strncpy(acpi_hdr.asl_compiler_id, dfl_id, 4);
> +        strzcpy(hdr.asl_compiler_id, buf, sizeof(hdr.asl_compiler_id));
> +        ++changed;
>      }
>
>      if (get_param_value(buf, sizeof(buf), "asl_compiler_rev", t)) {
> -        val = strtol(buf, &p, 10);
> -        if(*p != '\0')
> -            goto out;
> -    } else {
> -        val = 1;
> -    }
> -    acpi_hdr.asl_compiler_revision = cpu_to_le32(val);
> -
> -    if (!get_param_value(buf, sizeof(buf), "data", t)) {
> -         buf[0] = '\0';
> -    }
> -
> -    length = sizeof(acpi_hdr);
> -
> -    f = buf;
> -    while (buf[0]) {
> -        struct stat s;
> -        char *n = strchr(f, ':');
> -        if (n)
> -            *n = '\0';
> -        if(stat(f, &s) < 0) {
> -            fprintf(stderr, "Can't stat file '%s': %s\n", f, strerror(errno));
> -            goto out;
> +        val = strtol(buf, &p, 0);
> +        if (*p) {
> +            fprintf(stderr, "acpitable: \"%s=%s\" is invalid\n",
> +                    "asl_compiler_rev", buf);
> +            return -1;
>          }
> -        length += s.st_size;
> -        if (!n)
> -            break;
> -        *n = ':';
> -        f = n + 1;
> +        hdr.asl_compiler_revision = cpu_to_le32(val);
> +        ++changed;
>      }
>
> -    if (!acpi_tables) {
> -        acpi_tables_len = sizeof(uint16_t);
> -        acpi_tables = qemu_mallocz(acpi_tables_len);
> +    if (!has_header && !changed) {
> +        fprintf(stderr, "warning: acpitable: no table headers are specified\n");
>      }
> -    acpi_tables = qemu_realloc(acpi_tables,
> -                               acpi_tables_len + sizeof(uint16_t) + length);
> -    p = acpi_tables + acpi_tables_len;
> -    acpi_tables_len += sizeof(uint16_t) + length;
> -
> -    *(uint16_t*)p = cpu_to_le32(length);
> -    p += sizeof(uint16_t);
> -    memcpy(p, &acpi_hdr, sizeof(acpi_hdr));
> -    off = sizeof(acpi_hdr);
> -
> -    f = buf;
> -    while (buf[0]) {
> -        struct stat s;
> -        int fd;
> -        char *n = strchr(f, ':');
> -        if (n)
> -            *n = '\0';
> -        fd = open(f, O_RDONLY);
> -
> -        if(fd < 0)
> -            goto out;
> -        if(fstat(fd, &s) < 0) {
> -            close(fd);
> -            goto out;
> -        }
>
> -        /* off < length is necessary because file size can be changed
> -           under our foot */
> -        while(s.st_size && off < length) {
> -            int r;
> -            r = read(fd, p + off, s.st_size);
> -            if (r > 0) {
> -                off += r;
> -                s.st_size -= r;
> -            } else if ((r < 0 && errno != EINTR) || r == 0) {
> -                close(fd);
> -                goto out;
> -            }
> -        }
>
> -        close(fd);
> -        if (!n)
> -            break;
> -        f = n + 1;
> -    }
> -    if (off < length) {
> -        /* don't pass random value in process to guest */
> -        memset(p + off, 0, length - off);
> +    /* now calculate checksum of the table, complete with the header */
> +    /* we may as well leave checksum intact if has_header is true */
> +    /* alternatively there may be a way to set cksum to a given value */
> +    hdr.checksum = 0;    /* for checksum calculation */
> +
> +    /* put header back */
> +    memcpy(f, &hdr, sizeof(hdr));
> +
> +    if (changed || !has_header || 1) {
> +        ((struct acpi_table_header *)f)->checksum =
> +            acpi_checksum((uint8_t *)f + ACPI_TABLE_PFX_SIZE, len);
>      }
>
> -    acpi_hdr_p = (struct acpi_table_header*)p;
> -    acpi_hdr_p->length = cpu_to_le32(length);
> -    acpi_hdr_p->checksum = acpi_checksum((uint8_t*)p, length);
>      /* increase number of tables */
> -    (*(uint16_t*)acpi_tables) =
> -           cpu_to_le32(le32_to_cpu(*(uint16_t*)acpi_tables) + 1);
> +    (*(uint16_t *)acpi_tables) =
> +        cpu_to_le32(le32_to_cpu(*(uint16_t *)acpi_tables) + 1);
> +
> +    acpi_tables_len = allen;
>      return 0;
> -out:
> -    if (acpi_tables) {
> -        qemu_free(acpi_tables);
> -        acpi_tables = NULL;
> -    }
> -    return -1;
> +
>  }
>
>  /* ACPI PM1a EVT */
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 82e085a..e639d5a 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1014,12 +1014,17 @@ Enable virtio balloon device (default), optionally with PCI address
>  ETEXI
>
>  DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
> -    "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]\n"
> +    "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]\n"
>      "                ACPI table description\n", QEMU_ARCH_I386)
>  STEXI
>  @item -acpitable [sig=@var{str}][,rev=@var{n}][,oem_id=@var{str}][,oem_table_id=@var{str}][,oem_rev=@var{n}] [,asl_compiler_id=@var{str}][,asl_compiler_rev=@var{n}][,data=@var{file1}[:@var{file2}]...]
>  @findex -acpitable
>  Add ACPI table with specified header fields and context from specified files.
> +For file=, take whole ACPI table from the specified files, including all
> +ACPI headers (possible overridden by other options).
> +For data=, only data
> +portion of the table is used, all header information is specified in the
> +command line.
>  ETEXI
>
>  DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
> --
> 1.7.2.5
>
>