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virPCIVPDReadVPDBytes: Refactor error handling

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Each caller was checking that the function read as many bytes as it
expected. Move the check inside virPCIVPDReadVPDBytes and make it report
a proper error rather than just a combination of VIR_DEBUG inside the
function and a random VIR_INFO in the caller.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This commit is contained in:
Peter Krempa 2024-01-29 23:33:07 +01:00
parent e1dc851e7c
commit c15a495902
1 changed files with 38 additions and 35 deletions
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73
src/util/virpcivpd.c
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@ -361,34 +361,40 @@ virPCIVPDResourceUpdateKeyword(virPCIVPDResource *res,
* @offset: The offset at which bytes need to be read.
* @csum: A pointer to a byte containing the current checksum value. Mutated by this function.
*
* Returns: the number of VPD bytes read from the specified file descriptor. The csum value is
* Returns 0 if exactly @count bytes were read from @vpdFileFd. The csum value is
* also modified as bytes are read. If an error occurs while reading data from the VPD file
* descriptor, it is reported and -1 is returned to the caller. If EOF is occurred, 0 is returned
* to the caller.
* descriptor, it is reported and -1 is returned to the caller.
*/
static size_t
virPCIVPDReadVPDBytes(int vpdFileFd, uint8_t *buf, size_t count, off_t offset, uint8_t *csum)
static int
virPCIVPDReadVPDBytes(int vpdFileFd,
uint8_t *buf,
size_t count,
off_t offset,
uint8_t *csum)
{
ssize_t numRead = pread(vpdFileFd, buf, count, offset);
if (numRead == -1) {
VIR_DEBUG("Unable to read %zu bytes at offset %zd from fd: %d",
count, (ssize_t)offset, vpdFileFd);
} else if (numRead) {
/*
* Update the checksum for every byte read. Per the PCI(e) specs
* the checksum is correct if the sum of all bytes in VPD from
* VPD address 0 up to and including the VPD-R RV field's first
* data byte is zero.
*/
while (count--) {
*csum += *buf;
buf++;
}
if (numRead != count) {
virReportError(VIR_ERR_OPERATION_FAILED, "%s",
_("failed to read the PCI VPD data"));
return -1;
}
return numRead;
/*
* Update the checksum for every byte read. Per the PCI(e) specs
* the checksum is correct if the sum of all bytes in VPD from
* VPD address 0 up to and including the VPD-R RV field's first
* data byte is zero.
*/
while (count--) {
*csum += *buf;
buf++;
}
return 0;
}
/**
* virPCIVPDParseVPDLargeResourceFields:
* @vpdFileFd: A file descriptor associated with a file containing PCI device VPD.
@ -423,12 +429,9 @@ virPCIVPDParseVPDLargeResourceFields(int vpdFileFd, uint16_t resPos, uint16_t re
g_autofree char *fieldValue = NULL;
/* Keyword resources consist of keywords (2 ASCII bytes per the spec) and 1-byte length. */
if (virPCIVPDReadVPDBytes(vpdFileFd, buf, 3, fieldPos, csum) != 3) {
/* Invalid field encountered which means the resource itself is invalid too. Report
* That VPD has invalid format and bail. */
VIR_INFO("Could not read a resource field header - VPD has invalid format");
if (virPCIVPDReadVPDBytes(vpdFileFd, buf, 3, fieldPos, csum) < 0)
return false;
}
fieldDataLen = buf[2];
/* Change the position to the field's data portion skipping the keyword and length bytes. */
fieldPos += 3;
@ -474,10 +477,10 @@ virPCIVPDParseVPDLargeResourceFields(int vpdFileFd, uint16_t resPos, uint16_t re
VIR_INFO("A field data length violates the resource length boundary.");
return false;
}
if (virPCIVPDReadVPDBytes(vpdFileFd, buf, bytesToRead, fieldPos, csum) != bytesToRead) {
VIR_INFO("Could not parse a resource field data - VPD has invalid format");
if (virPCIVPDReadVPDBytes(vpdFileFd, buf, bytesToRead, fieldPos, csum) < 0)
return false;
}
/* Advance the position to the first byte of the next field. */
fieldPos += fieldDataLen;
@ -566,10 +569,9 @@ virPCIVPDParseVPDLargeResourceString(int vpdFileFd, uint16_t resPos,
/* The resource value is not NULL-terminated so add one more byte. */
g_autofree char *buf = g_malloc0(resDataLen + 1);
if (virPCIVPDReadVPDBytes(vpdFileFd, (uint8_t *)buf, resDataLen, resPos, csum) != resDataLen) {
VIR_INFO("Could not read a part of a resource - VPD has invalid format");
if (virPCIVPDReadVPDBytes(vpdFileFd, (uint8_t *)buf, resDataLen, resPos, csum) < 0)
return false;
}
resValue = g_strdup(g_strstrip(buf));
if (!virPCIVPDResourceIsValidTextValue(resValue)) {
VIR_INFO("The string resource has invalid characters in its value");
@ -610,8 +612,8 @@ virPCIVPDParse(int vpdFileFd)
while (resPos <= PCI_VPD_ADDR_MASK) {
/* Read the resource data type tag. */
if (virPCIVPDReadVPDBytes(vpdFileFd, &tag, 1, resPos, &csum) != 1)
break;
if (virPCIVPDReadVPDBytes(vpdFileFd, &tag, 1, resPos, &csum) < 0)
return NULL;
/* 0x80 == 0b10000000 - the large resource data type flag. */
if (tag & PCI_VPD_LARGE_RESOURCE_FLAG) {
@ -620,9 +622,10 @@ virPCIVPDParse(int vpdFileFd)
* where the end tag should be. */
break;
}
/* Read the two length bytes of the large resource record. */
if (virPCIVPDReadVPDBytes(vpdFileFd, headerBuf, 2, resPos + 1, &csum) != 2)
break;
if (virPCIVPDReadVPDBytes(vpdFileFd, headerBuf, 2, resPos + 1, &csum) < 0)
return NULL;
resDataLen = headerBuf[0] + (headerBuf[1] << 8);
/* Change the position to the byte following the tag and length bytes. */