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modinfo: fix module parsing with kernel >= 2.6.37

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display() function returns the length of the value we are displaying + 1.
As a consequence, if we have field=value\0field=value\0field=value in the
binary, then the second occurence will be skipped as ptr will miss the first
character of the following field.

Example trying to list aliases from ixgbe.ko on a 3.2 kernel.

- In the module we have:
alias=pci:v00008086d00001560sv*sd*bc*sc*i*\0
alias=pci:v00008086d0000154Asv*sd*bc*sc*i*\0
alias=pci:v00008086d00001557sv*sd*bc*sc*i*\0
alias=pci:v00008086d0000154Fsv*sd*bc*sc*i*\0
alias=pci:v00008086d0000154Dsv*sd*bc*sc*i*\0
...

- Using modinfo -F alias ixgbe returns:
alias:          pci:v00008086d00001560sv*sd*bc*sc*i*
alias:          pci:v00008086d00001557sv*sd*bc*sc*i*
alias:          pci:v00008086d0000154Dsv*sd*bc*sc*i*
...

This problem appeared with kernel commit "modules: no need to align .modinfo
strings" b6472776816af1ed52848c93d26e3edb3b17adab in 2.6.37.

Fix this by not trusting display() return value but increment ptr by strlen(ptr)
(the same way as depmod.c does).

Signed-off-by: David Marchand <david.marchand@6wind.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
David Marchand 2014-07-03 12:24:55 +02:00 committed by Denys Vlasenko
parent 03e17bfa8d
commit 7d16964c3e
1 changed files with 4 additions and 3 deletions
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7
modutils/modinfo.c
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@ -34,14 +34,14 @@ struct modinfo_env {
int tags; int tags;
}; };
static int display(const char *data, const char *pattern, int flag) static void display(const char *data, const char *pattern, int flag)
{ {
if (flag) { if (flag) {
int n = printf("%s:", pattern); int n = printf("%s:", pattern);
while (n++ < 16) while (n++ < 16)
bb_putchar(' '); bb_putchar(' ');
} }
return printf("%s%c", data, (option_mask32 & OPT_0) ? '\0' : '\n'); printf("%s%c", data, (option_mask32 & OPT_0) ? '\0' : '\n');
} }
static void modinfo(const char *path, const char *version, static void modinfo(const char *path, const char *version,
@ -104,7 +104,8 @@ static void modinfo(const char *path, const char *version,
/* field prefixes are 0x80 or 0x00 */ /* field prefixes are 0x80 or 0x00 */
if ((ptr[-1] & 0x7F) == '\0') { if ((ptr[-1] & 0x7F) == '\0') {
ptr += length + 1; ptr += length + 1;
ptr += display(ptr, pattern, (1<<j) != tags); display(ptr, pattern, (1<<j) != tags);
ptr += strlen(ptr);
} }
} }
++ptr; ++ptr;