Patchwork [1/4] Introduce strtosz() library function to convert a string to a byte count.

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Submitter Jes Sorensen
Date Oct. 13, 2010, 8:48 a.m.
Message ID <1286959730-924-2-git-send-email-Jes.Sorensen@redhat.com>
Download mbox | patch
Permalink /patch/67681/
State New
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Comments

Jes Sorensen - Oct. 13, 2010, 8:48 a.m.
From: Jes Sorensen <Jes.Sorensen@redhat.com>

strtosz() returns -1 on error. It now supports human unit formats in
eg. 1.0G, with better error handling.

The following suffixes are supported:
B/b = bytes
K/k = KB
M/m = MB
G/g = GB
T/t = TB

This patch changes -numa and -m input to use strtosz().

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 cutils.c      |   79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu-common.h |    1 +
 vl.c          |   31 +++++++---------------
 3 files changed, 90 insertions(+), 21 deletions(-)
Markus Armbruster - Oct. 13, 2010, 1:28 p.m.
Jes.Sorensen@redhat.com writes:

> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>
> strtosz() returns -1 on error. It now supports human unit formats in
> eg. 1.0G, with better error handling.
>
> The following suffixes are supported:
> B/b = bytes
> K/k = KB
> M/m = MB
> G/g = GB
> T/t = TB
>
> This patch changes -numa and -m input to use strtosz().
>
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  cutils.c      |   79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qemu-common.h |    1 +
>  vl.c          |   31 +++++++---------------
>  3 files changed, 90 insertions(+), 21 deletions(-)
>
> diff --git a/cutils.c b/cutils.c
> index 5883737..4bb459d 100644
> --- a/cutils.c
> +++ b/cutils.c
> @@ -23,6 +23,7 @@
>   */
>  #include "qemu-common.h"
>  #include "host-utils.h"
> +#include <math.h>
>  
>  void pstrcpy(char *buf, int buf_size, const char *str)
>  {
> @@ -283,3 +284,81 @@ int fcntl_setfl(int fd, int flag)
>  }
>  #endif
>  
> +/*
> + * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
> + * M/m for MB, G/g for GB or T/t for TB. Default without any postfix
> + * is MB. End pointer will be returned in *end, if not NULL.
> + * Return -1 on error.
> + */
> +ssize_t strtosz(const char *nptr, char **end)
> +{
> +    ssize_t retval = -1;
> +    char *endptr, c;
> +    int mul_required = 0;
> +    double val, mul, integral, fraction;
> +
> +    errno = 0;
> +    val = strtod(nptr, &endptr);
> +    if (isnan(val) || endptr == nptr || errno != 0 || val < 0 ||
> +        val >= HUGE_VAL) {
> +        goto fail;
> +    }
> +    integral = modf(val, &fraction);
> +    if (integral != 0) {
> +        mul_required = 1;
> +    }
> +    /*
> +     * Any whitespace character is fine for terminating the number,
> +     * in addition we accept ',' to handle strings where the size is
> +     * part of a multi token argument. Otherwise check that the suffix
> +     * is just one character.
> +     */
> +    c = *endptr++;

Uh-oh...

> +    if (isspace(c) || c == '\0' || c == ',') {
> +        c = 0;
> +    } else if (!isspace(*endptr) && *endptr != 0) {
> +        goto fail;
> +    }
> +    switch (c) {
> +    case 'B':
> +    case 'b':
> +        mul = 1;
> +        if (mul_required) {
> +            goto fail;
> +        }
> +        break;
> +    case 'K':
> +    case 'k':
> +        mul = 1 << 10;
> +        break;
> +    case 0:
> +        if (mul_required) {
> +            goto fail;
> +        }
> +    case 'M':
> +    case 'm':
> +        mul = 1ULL << 20;
> +        break;
> +    case 'G':
> +    case 'g':
> +        mul = 1ULL << 30;
> +        break;
> +    case 'T':
> +    case 't':
> +        mul = 1ULL << 40;
> +        break;
> +    default:
> +        goto fail;
> +    }

I'm afraid strtosz("1.0x", &end) makes end point behind the 'x' instead
of to the 'x'.

Solution: increment endptr when the unit character is consumed,
i.e. after the switch.  Finish consuming the unit character before
checking the suffix.

> +    if (val * mul >= ~(size_t)0) {
> +        goto fail;
> +    }
> +    retval = (val * mul);
> +
> +fail:
> +    if (end) {
> +        *end = endptr;
> +    }
> +
> +    return retval;
> +}
[...]

Patch

diff --git a/cutils.c b/cutils.c
index 5883737..4bb459d 100644
--- a/cutils.c
+++ b/cutils.c
@@ -23,6 +23,7 @@ 
  */
 #include "qemu-common.h"
 #include "host-utils.h"
+#include <math.h>
 
 void pstrcpy(char *buf, int buf_size, const char *str)
 {
@@ -283,3 +284,81 @@  int fcntl_setfl(int fd, int flag)
 }
 #endif
 
+/*
+ * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
+ * M/m for MB, G/g for GB or T/t for TB. Default without any postfix
+ * is MB. End pointer will be returned in *end, if not NULL.
+ * Return -1 on error.
+ */
+ssize_t strtosz(const char *nptr, char **end)
+{
+    ssize_t retval = -1;
+    char *endptr, c;
+    int mul_required = 0;
+    double val, mul, integral, fraction;
+
+    errno = 0;
+    val = strtod(nptr, &endptr);
+    if (isnan(val) || endptr == nptr || errno != 0 || val < 0 ||
+        val >= HUGE_VAL) {
+        goto fail;
+    }
+    integral = modf(val, &fraction);
+    if (integral != 0) {
+        mul_required = 1;
+    }
+    /*
+     * Any whitespace character is fine for terminating the number,
+     * in addition we accept ',' to handle strings where the size is
+     * part of a multi token argument. Otherwise check that the suffix
+     * is just one character.
+     */
+    c = *endptr++;
+    if (isspace(c) || c == '\0' || c == ',') {
+        c = 0;
+    } else if (!isspace(*endptr) && *endptr != 0) {
+        goto fail;
+    }
+    switch (c) {
+    case 'B':
+    case 'b':
+        mul = 1;
+        if (mul_required) {
+            goto fail;
+        }
+        break;
+    case 'K':
+    case 'k':
+        mul = 1 << 10;
+        break;
+    case 0:
+        if (mul_required) {
+            goto fail;
+        }
+    case 'M':
+    case 'm':
+        mul = 1ULL << 20;
+        break;
+    case 'G':
+    case 'g':
+        mul = 1ULL << 30;
+        break;
+    case 'T':
+    case 't':
+        mul = 1ULL << 40;
+        break;
+    default:
+        goto fail;
+    }
+    if (val * mul >= ~(size_t)0) {
+        goto fail;
+    }
+    retval = (val * mul);
+
+fail:
+    if (end) {
+        *end = endptr;
+    }
+
+    return retval;
+}
diff --git a/qemu-common.h b/qemu-common.h
index 81aafa0..0a062d4 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -153,6 +153,7 @@  time_t mktimegm(struct tm *tm);
 int qemu_fls(int i);
 int qemu_fdatasync(int fd);
 int fcntl_setfl(int fd, int flag);
+ssize_t strtosz(const char *nptr, char **end);
 
 /* path.c */
 void init_paths(const char *prefix);
diff --git a/vl.c b/vl.c
index df414ef..6043fa2 100644
--- a/vl.c
+++ b/vl.c
@@ -734,16 +734,13 @@  static void numa_add(const char *optarg)
         if (get_param_value(option, 128, "mem", optarg) == 0) {
             node_mem[nodenr] = 0;
         } else {
-            value = strtoull(option, &endptr, 0);
-            switch (*endptr) {
-            case 0: case 'M': case 'm':
-                value <<= 20;
-                break;
-            case 'G': case 'g':
-                value <<= 30;
-                break;
+            ssize_t sval;
+            sval = strtosz(option, NULL);
+            if (sval < 0) {
+                fprintf(stderr, "qemu: invalid numa mem size: %s\n", optarg);
+                exit(1);
             }
-            node_mem[nodenr] = value;
+            node_mem[nodenr] = sval;
         }
         if (get_param_value(option, 128, "cpus", optarg) == 0) {
             node_cpumask[nodenr] = 0;
@@ -2163,18 +2160,10 @@  int main(int argc, char **argv, char **envp)
                 exit(0);
                 break;
             case QEMU_OPTION_m: {
-                uint64_t value;
-                char *ptr;
+                ssize_t value;
 
-                value = strtoul(optarg, &ptr, 10);
-                switch (*ptr) {
-                case 0: case 'M': case 'm':
-                    value <<= 20;
-                    break;
-                case 'G': case 'g':
-                    value <<= 30;
-                    break;
-                default:
+                value = strtosz(optarg, NULL);
+                if (value < 0) {
                     fprintf(stderr, "qemu: invalid ram size: %s\n", optarg);
                     exit(1);
                 }