Fix: Time-of-check time-of-use filesystem race condition

[brustolin]

Fixes https://github.com/getsentry/sentry-cocoa/security/code-scanning/6

To fix the TOCTOU race condition, we should avoid using stat and open separately. Instead, we can use the open function with the O_RDONLY flag to open the file directly and then use fstat to get the file status. This ensures that the file we are operating on is the same file we checked, as both operations are performed on the file descriptor.

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1244.00 ms	1265.75 ms	21.75 ms
Size	21.90 KiB	709.17 KiB	687.26 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
e80771f	1208.41 ms	1233.94 ms	25.53 ms
1ce939e	1216.79 ms	1242.38 ms	25.59 ms
86b89b9	1237.28 ms	1256.27 ms	18.99 ms
fb53d97	1226.08 ms	1245.12 ms	19.04 ms
5de0a56	1214.49 ms	1235.56 ms	21.07 ms
3a6495e	1227.61 ms	1239.22 ms	11.60 ms
3297d6e	1203.79 ms	1218.76 ms	14.97 ms
ca91a5c	1234.53 ms	1249.86 ms	15.33 ms
4d5eb78	1197.86 ms	1215.73 ms	17.88 ms
feba2be	1246.67 ms	1254.64 ms	7.97 ms

App size

Revision	Plain	With Sentry	Diff
e80771f	21.58 KiB	697.69 KiB	676.10 KiB
1ce939e	22.85 KiB	412.98 KiB	390.13 KiB
86b89b9	21.58 KiB	638.25 KiB	616.66 KiB
fb53d97	20.76 KiB	425.81 KiB	405.04 KiB
5de0a56	20.76 KiB	432.87 KiB	412.11 KiB
3a6495e	21.58 KiB	422.66 KiB	401.08 KiB
3297d6e	21.58 KiB	418.45 KiB	396.86 KiB
ca91a5c	22.84 KiB	403.19 KiB	380.34 KiB
4d5eb78	21.58 KiB	418.74 KiB	397.16 KiB
feba2be	20.76 KiB	414.45 KiB	393.69 KiB

Previous results on branch: fix-TOCTOU-filesystem-race-condition

Startup times

Revision	Plain	With Sentry	Diff
214bed9	1211.96 ms	1235.48 ms	23.52 ms

App size

Revision	Plain	With Sentry	Diff
214bed9	21.90 KiB	709.00 KiB	687.10 KiB

[philipphofmann]

LGTM, but I think we should still ask somebody from the native team to have a look.

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 91.797%. Comparing base (2095ae0) to head (df9c421).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...SentryCrash/Recording/Tools/SentryCrashFileUtils.c	60.000%	2 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #4473       +/-   ##
=============================================
- Coverage   91.803%   91.797%   -0.007%     
=============================================
  Files          611       611               
  Lines        68300     68294        -6     
  Branches     24529     24511       -18     
=============================================
- Hits         62702     62692       -10     
- Misses        5507      5509        +2     
- Partials        91        93        +2     

Files with missing lines	Coverage Δ
...SentryCrash/Recording/Tools/SentryCrashFileUtils.c	85.882% <60.000%> (ø)

... and 10 files with indirect coverage changes

---

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[JoshuaMoelans]

lgtm!