hal: check strstr() results before dereferencing them

[wjames111]

hal_identify() and hal_temperature_read() search text read from kernel
files (/proc/cmdline for LX_MEM=, /sys/devices/soc0/machine for SSC,
the msys TEMP_R node for "Temperature ") and use the result without
checking it. When a node is missing, empty or worded differently,
strstr() returns NULL and divinus segfaults during identification, or
on GET /api/status in the temperature case.

Only use each value when the read succeeded and the match was found,
and make sure the SSC match is long enough for the three characters
copied out of it.

Built for infinity6e (SSC338Q). We've been running this fix on SSC338Q units.

[qodo-free-for-open-source-projects]

PR Summary by Qodo

Guard HAL parsing against missing kernel text

🐞 Bug fix 🕐 Less than 10 minutes

AI Description

• Prevent crashes when kernel files are empty or omit expected memory, board, or temperature text.
• Require enough board text before copying the package identifier.

Diagram

graph TD
  K["Kernel text files"] --> R{"Read succeeded?"} -->|yes| M{"Token found?"} -->|yes| B{"SSC token?"} -->|yes| L{"Length at least 7?"} -->|yes| P["Update HAL values"]
  B -->|no| P
  R -->|no| D["Keep defaults"]
  M -->|no| D
  L -->|no| D

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High-Level Assessment

Keep the localized guards: they address the three crash paths without changing HAL detection or temperature behavior for valid input. A shared parser would add abstraction for three distinct formats without a clear benefit.

Files changed (1) +16 / -9

Bug fix (1) +16 / -9

support.cGuard kernel-text matches before HAL parsing +16/-9

Guard kernel-text matches before HAL parsing

• Checks that reads succeed and expected tokens are present before parsing LX_MEM and temperature values. Copies the SSC package identifier only when the match contains all required characters, leaving initialized or previously recorded values unchanged otherwise.

src/hal/support.c

[qodo-free-for-open-source-projects]

Code Review by Qodo

🐞 Bugs (1) 📘 Rule violations (0) 📎 Requirement gaps (0) 🎨 UX issues (0) 🔗 Cross-repo conflicts (0) 📜 Skill insights (0)

1. Status shows stale temperatures 🐞 Bug ≡ Correctness

Description

hal_temperature_read() leaves lastReadTemp unchanged when the new parsed guard rejects a line,
even though it has already advanced lastMillisTemp. If TEMP_R stops containing Temperature 
after a successful reading, /api/status and the temperature overlay keep displaying the old value
until a valid reading returns.

Code

src/hal/support.c[R349-350]

+                if (parsed)
+                    lastReadTemp = strtof(parsed + 12, &remain);

Evidence

The timestamp is set before the file is read, while the added guard skips the only assignment to
lastReadTemp when the marker is absent. Both output paths format the returned cached value without
checking whether this refresh succeeded.

src/hal/support.c[332-352]
src/server.c[1559-1570]
src/region.c[86-94]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
A missing temperature marker leaves the previous reading cached and visible as current.
## Fix Focus Areas
- src/hal/support.c[332-352]
- src/server.c[1559-1570]
- src/region.c[86-94]
## Recommended Fix
On an unsuccessful temperature read or parse, invalidate the cached value rather than retaining the previous reading. Have status and overlay formatting display an unavailable value when no valid temperature exists; only mark a reading fresh after a successful parse.

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

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[qodo-free-for-open-source-projects]

1. Status shows stale temperatures 🐞 Bug ≡ Correctness

hal_temperature_read() leaves lastReadTemp unchanged when the new parsed guard rejects a line,
even though it has already advanced lastMillisTemp. If TEMP_R stops containing Temperature 
after a successful reading, /api/status and the temperature overlay keep displaying the old value
until a valid reading returns.

Agent Prompt

## Issue description
A missing temperature marker leaves the previous reading cached and visible as current.

## Fix Focus Areas
- src/hal/support.c[332-352]
- src/server.c[1559-1570]
- src/region.c[86-94]

## Recommended Fix
On an unsuccessful temperature read or parse, invalidate the cached value rather than retaining the previous reading. Have status and overlay formatting display an unavailable value when no valid temperature exists; only mark a reading fresh after a successful parse.

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

[wberube]

Thank you very much for your contribution!